Patent Publication Number: US-11039829-B2

Title: Apparatus and method for minimally invasive suturing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of priority to and is a continuation of U.S. patent application Ser. No. 15/661,463, filed Jul. 27, 2017, now U.S. Pat. No. 10,292,698. 
     This patent application is related to U.S. patent application Ser. No. 15/265,650, filed Sep. 14, 2016, which is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 14/796,642, filed Jul. 10, 2015, now U.S. Pat. No. 9,474,523, which is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 14/472,090, filed Aug. 28, 2014, now U.S. Pat. No. 9,451,948, which is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 13/361,444 filed Jan. 30, 2012, now U.S. Pat. No. 8,821,519, which is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 12/592,174, filed on Nov. 20, 2009, now U.S. Pat. No. 8,123,764, which is a continuation-in-part of and claims the benefit of priority to U.S. patent application Ser. No. 11/231,135, filed Sep. 20, 2005, now U.S. Pat. No. 7,862,572, which in turn claims the benefit of priority to U.S. Provisional Application Ser. No. 60/611,362, filed Sep. 20, 2004. 
     This patent application is also related to International Application No. PCT/US2008/06674 filed May 23, 2008, which in turn claims the benefit of priority to U.S. Provisional Application Ser. No. 60/939,887, filed May 24, 2007. This patent application is also related to U.S. patent application Ser. No. 12/175,442, filed Jul. 17, 2008, and U.S. Provisional Application Ser. No. 61/200,180, filed Nov. 25, 2008. 
     Each of the aforementioned patent applications is incorporated by reference herein in its entirety for any purpose whatsoever. 
    
    
     FIELD 
     The embodiments disclosed herein relate to a medical device for suturing tissue, and more particularly to a device for the manipulation and control of a suturing needle during minimally invasive suturing, methods for making such a device and methods for using such a device for suturing tissue. 
     BACKGROUND 
     Minimally invasive surgery (MIS) has allowed physicians to carry out many surgical procedures with less pain and disability than conventional, open surgery. Unlike conventional open surgery, where the surgical site is readily accessible through a large incision, enabling the surgeon to easily visualize and manipulate both tissue and instruments, MIS requires the surgeon to operate remotely by inserting and manipulating instruments through small punctures (“keyhole surgery”) or through natural orifices, including for example the vagina, the esophagus, or the anus. 
     In MIS, a small puncture is typically made in the body. Medical instruments are then inserted through a cannula. A cannula has a small inside diameter, typically 5-10 millimeters (mm), and sometimes up to 20 millimeters (mm) or more. A number of such cannulas may be inserted into the body for any given operation. Minimally invasive surgical instruments are necessarily smaller, and are also generally longer and therefore are more difficult to manipulate with precision. 
     Perhaps the most problematic surgical task in MIS is suturing. Suturing requires coordinated manipulation with both hands of small needles and sutures that are difficult to visualize (particularly when only indirect, two-dimensional video imaging is available) as well as the several instruments (including needle-drivers and pick-up forceps) ordinarily used to suture by hand. In an environment characterized by limited space, limited visualization, and limited mobility, many surgeons find minimally invasive suturing by hand an extremely difficult, often virtually impossible, surgical task. 
     In the preferred method of suturing by hand, a grasping forceps (“needle driver”) is held by the surgeon and is used to grip a curved needle near the needle&#39;s tail. Pronation of the surgeon&#39;s wrist drives the needle into the tissue. When the point of the curved needle emerges from the tissue, the surgeon releases the needle from the grip of the needle driver and grasps the point with another forceps (“pick-ups”). The surgeon then pulls the curved needle by the needle point, preferably in a circular path following the arc of the needle&#39;s curvature to follow the most atraumatic path through the tissue, until the entire length of the needle has exited the tissue. Each time a stitch is placed, the curved needle is thus driven around in a complete circular arc. Individual (interrupted) stitches are placed by tying off the suture following placement of each stitch. Running (continuous) stitches are placed by repeatedly driving the curved needle in a complete circular arc repeatedly until the desired length of suture and number of stitches has been placed. In order to place additional interrupted or continuous stitches, the surgeon must let go of the point of the needle and re-grasp the needle near the needle&#39;s tail. 
     In the manual suturing technique described above, the direct handling of the needle can result in accidental needle pricks through a surgeon or nurse&#39;s gloves, posing a potential risk of infection for the surgeon, nurse, staff, and patient, or cause the needle to become contaminated with pathogenic bacteria that can cause onset of infection at the site of the sutures. There is also a risk of the needle penetrating internal organs or vessels and causing a serious, and often fatal infection. 
     Various devices for suturing for MIS are described in U.S. Pat. No. 5,643,295 entitled “Methods and Apparatus for Suturing Tissue”; U.S. Pat. No. 5,665,096 entitled “Needle Driving Apparatus and Methods of Suturing Tissue”; U.S. Pat. No. 5,665,109 entitled “Methods and Apparatus for Suturing Tissue”; U.S. Pat. No. 5,759,188 entitled “Suturing Instrument with Rotatably Mounted Needle Driver and Catcher”; U.S. Pat. No. 5,860,992 entitled “Endoscopic Suturing Devices and Methods”; U.S. Pat. No. 5,954,733 entitled “Suturing Instrument with Rotatably Mounted Needle Driver and Catcher”; U.S. Pat. No. 6,719,763 entitled “Endoscopic Suturing Device”; and U.S. Pat. No. 6,755,843 entitled “Endoscopic Suturing Device”, all of which are incorporated by reference in their entireties for the teachings therein. 
     Assignees&#39; U.S. Pat. Nos. 5,437,681, 5,540,705 and 6,923,819 disclose a suturing device with thread management comprising a protective cartridge, suturing needle and needle rotation drive, the disclosures of which are hereby incorporated by reference. The devices described in the above-mentioned patents and patent application comprise a mechanism for driving a protected needle however, the needle is rotated about an axis that is parallel to the axis of the device. In addition, the orientation and size of the suturing device makes it difficult to visualize and cumbersome to use for MIS. 
     Therefore, there remains a need in the art for a minimally invasive suturing device that is easily manipulated within the small diameter of the cannula; functions in an environment characterized by limited space, limited visualization, and limited mobility; mimics the preferred method of suturing used by surgeons; permits the surgeon to secure and tie knots quickly and with controlled tension; places continuous stitches; and protects user&#39;s from accidental needle sticks during needle handling, as well as internal organs and vessels, from inadvertent needle-pricks. 
     SUMMARY 
     Devices and methods for minimally invasive suturing of tissue internal to a body are disclosed herein. 
     According to aspects illustrated herein, there is provided a medical device for closing openings internal to a patient&#39;s body, which closely emulates or replicates the manual suturing actions carried out by a surgeon. The device offers several advantages over conventional methods used by surgeons for suturing tissue during minimally invasive surgery in that the device provides a hand-held suturing instrument of relatively simple mechanical construction that requires no external motive source. The presently disclosed embodiments provide relative ease of operation for the surgeon with only one hand. 
     According to aspects illustrated herein, a suture head assembly may be removably attached to an actuator mechanism of the suturing device. The diameter of the device is small enough to fit into a typical cannula, thus making the device extremely easy to maneuver, as well as suture, during endoscopic or other MIS procedures. Also, the suture head assembly of the device can be laterally articulated to the left of center, to the right of center, up, and down, once inside the cannula, which is ideal for use in the course of endoscopic surgery, including laparoscopy, thoracoscopy and arthroscopy, as well as other less-invasive surgical procedures. 
     The device of the present disclosed embodiments closely emulates or replicates the manual suturing actions carried out by a surgeon. For example, during manual suturing by hand, the needle is held in forceps and travels in a circular arc with no obstructions anywhere in the interior of the arc. The design of the suturing device of the present disclosed embodiments allows for a lack of obstruction in the center of the arc of the needle during suturing. In other words, there is no hub at the center of the circular arc of the suturing needle. The entire area within the circular arc of the needle is unobstructed. This allows for the user to have better visualization during operation, unlike the present mechanical suturing methods, while maintaining control over needle movement. 
     In accordance with one embodiment a “locomotive-type” drive mechanism is provided for advancing the needle about a path of travel. This embodiment of a drive enables the small diameter of the device and affords better visualization during operation because of the lack of a hub. There are many benefits afforded by the design of the suturing device of the presently disclosed embodiments, including, but not limited to, more tissue being able to fit into the device, thus enabling a bigger bite of tissue and a more secure suture; the device can be used to ligate, that is, place a loop of suture around a blood vessel, duct, or other tubular structure; and the device can be inserted further into smaller incisions/openings (one side of the aperture can be inserted deeply, for example). 
     A benefit provided by the suturing device of the presently disclosed embodiments is that the device enables maneuvering a suturing material through a tissue incision in a manner substantially similar to the way a surgeon would do so by hand. In particular, the suturing device first pushes a suturing needle from the tail of the needle and drives the point of the needle through the tissue. The device then picks up the point of the needle that passed through the tissue, and pulls the remainder of the suturing needle and the suture attached to the suturing needle through the tissue. The suturing needle thus consistently follows the arc of the needle&#39;s own curve, which is the preferred method of suturing, in the most atraumatic way of passing a needle through tissue. A benefit provided by the suturing device of the presently disclosed embodiments is the ability of the suturing needle to pull the suturing thread entirely through the tissue segments being closed, following each stitch. When using the suturing device of the presently disclosed embodiments, no ancillary instruments or tools such as needle holders, pick-up forceps or the like are needed to complete the stitch. A forceps can be used to tighten the knots. 
     According to aspects illustrated herein, there is provided a suturing device that includes a suturing needle that is protected by a housing, the suturing needle is not exposed to or handled directly by the user, thereby preventing inadvertent needle sticks. The configuration of the suturing device of the presently disclosed embodiments also protects against inadvertent penetration of internal organs or vessels by the needle, since the housing acts as a shield between the organs and the needle. 
     The suturing device of the presently disclosed embodiments is useful for suturing tissue internal to a body. An embodiment of the device includes an elongated barrel having a proximal end, a distal end, and a longitudinal axis therebetween; a suture head assembly extending from the distal end of the elongated barrel; a suturing needle having a pointed end and a blunt end, the suturing needle capable of rotating about an axis approximately perpendicular to a longitudinal axis of the elongated barrel, wherein the pointed end of the suturing needle is positioned within the suture head assembly prior to and after rotation of the suturing needle; and an actuator extending from the proximal end of the elongated barrel to actuate a drive mechanism having a needle driver for engaging and rotating the suturing needle. 
     According to aspects illustrated herein, there is provided a method for suturing tissue during minimally invasive surgery that includes: (a) engaging a cartridge to a suture head assembly at a distal end of a suturing device, the cartridge having a protective housing and a suturing needle with a pointed end and a blunt end; (b) introducing the distal end of the suturing device into a body cavity; (c) positioning an opening in the cartridge to span a plurality of separated tissue segments or a single tissue segment; (d) activating an actuator coupled to a drive mechanism that engages the suturing needle to cause rotational movement of the suturing needle about an axis approximately perpendicular to a longitudinal axis of the suturing device and advance the suturing needle through the plurality of separated tissue segments or the single tissue segment; (e) pulling a suturing material attached to the suturing needle through the plurality of separated tissue segments or the single tissue segment forming a stitch; and repeating steps (c) through (e) to cause a plurality of stitches to be placed through the separated tissue segments or the single tissue segment. 
     According to aspects illustrated herein, there is provided a method for suturing tissue during minimally invasive surgery that includes: (a) engaging a suturing needle with a pointed end and a blunt end to a suture head assembly at a distal end of a suturing device, the suture head assembly includes a curved track, whereby the suturing needle follows a curved path along the track during rotation of the suturing needle, and a latch that provides a protective housing for the suturing needle; (b) introducing the distal end of the suturing device into a body cavity; (c) positioning an opening in the needle holder assembly to span a plurality of separated tissue segments or a single tissue segment; (d) activating an actuator coupled to a drive mechanism that engages the suturing needle to cause rotational movement of the suturing needle about an axis approximately perpendicular to a longitudinal axis of the suturing device and advance the suturing needle through the plurality of separated tissue segments or the single tissue segment; (e) pulling a suturing material attached to the suturing needle through the plurality of separated tissue segments or a single tissue segment forming a stitch; and repeating steps (c) through (e) to cause a plurality of stitches to be placed through the separated tissue segments or a single tissue segment. 
     According to aspects illustrated herein, there is provided a method for suturing tissue during minimally invasive surgery that includes inserting a distal end of a suturing device having a suturing needle with a pointed end into a body; positioning the suturing needle to span a plurality of separated tissue segments; activating an actuator a first time causing the pointed end of the suturing needle to extend beyond a protective housing of a cartridge to engage the plurality of separated tissue segments; and activating the actuator a second time to cause the suturing needle to complete a revolution and pull a suture extending from the suturing needle through the plurality of separated tissue segments to form a stitch. 
     In addition to the advantages discussed above, the suturing device of the presently disclosed embodiments is relatively simple and cost efficient to manufacture. Therefore, the suturing device should find widespread suturing applications that include single stitches or continuous stitches, e.g. spiral, mattress, purse string, etc., that are required to close tissue incisions, attach grafts, or the like. 
     These and other advantages of the presently disclosed embodiments are illustrated through the embodiments described hereinafter. The presently disclosed embodiments accordingly comprise the features of construction, combination of elements and arrangement of parts that will be exemplified in the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments. 
         FIG. 1  is a perspective view of a suturing device of the presently disclosed embodiments. 
         FIGS. 2A and 2B  are views of the suture head assembly of the suturing device of  FIG. 1 .  FIG. 2A  is a perspective assembly view of the suture head.  FIG. 2B  is a cutaway perspective view of the suture head. 
         FIGS. 3A and 3B  are segmented assembly views of the suture head assembly of  FIG. 2 . 
         FIGS. 4A and 4B  are cutaway segmental views of the suture head assembly showing interaction points of a suturing needle with a portion of the drive mechanism.  FIG. 4A  shows the position of the suturing needle and drive mechanism in a “home” position prior to use or after a complete full cycle.  FIG. 4B  shows the position of the suturing needle and drive mechanism after one full actuation of the handle, where the suturing needle is in a “rotation” position. 
         FIG. 5 , including  FIGS. 5A and 5B  are expanded views of the working end of the suture head assembly with a suturing needle in the home position.  FIG. 5A  shows the relationship between the pawl and anti-rotate spring when the suturing needle is in the home position.  FIG. 5B  shows a close-up view of the anti-rotate spring. 
         FIGS. 6A and 6B  are expanded views of the working end of the suture head assembly during use of the device.  FIG. 6A  shows the position of the suturing needle and the pawl immediately after the user squeezes the handle. The user then releases the handle and the pawl returns to the start position ( FIG. 6B ) while the suturing needle remains in the rotation position. 
         FIG. 7 , including  FIGS. 7A and 7B  are expanded views of the pawl in contact with the C-brace while driving the suturing needle.  FIG. 7A  shows a close-up view of the pawl spring loaded with a spring.  FIG. 7B  shows a close-up view of the pawl, showing the heel and tip. 
         FIGS. 8 and 9  are side elevational views of a much larger scale of the internal portions of the drive mechanism located within the handle and elongated barrel.  FIG. 8  shows the drive mechanism when the handle is in an open position and  FIG. 9  shows the drive mechanism when the handle is in a closed position. 
         FIGS. 10-13  are top and bottom views of the suture head assembly, including cables that provide the connection between the drive mechanism located in the suture head assembly and the elongated barrel when the handle is in the open and closed positions. 
         FIG. 10  shows a top view when the handle is in the open position. 
         FIG. 11  shows a bottom view when the handle is in the open position. 
         FIG. 12  shows a top view when the handle is in the closed position. 
         FIG. 13  shows a bottom view when the handle is in the closed position. 
         FIG. 14  is a close-up view of the cartridge holder with a tab that locks into a mating groove on the cartridge holder assembly. 
         FIG. 15  is a view depicting the suturing needle positioned in the track of the cartridge. 
         FIG. 16  is a view showing the relation between the cartridge holder assembly, cartridge, latch and C-brace. 
         FIGS. 17A, 17B and 17C  show the suture head assembly.  FIG. 17A  shows a side view of the suture head assembly.  FIG. 17B  is a close-up side view showing the relationship between the lever and latch during attachment and ejection of the needle and cartridge from the cartridge holder assembly.  FIG. 17C  shows a top view of the suture head assembly. 
         FIG. 18  is an expanded view of a curved suturing needle with notches depicted on the surface of the needle. 
         FIGS. 19A and 19B  depict two exemplary embodiments of the curved suturing needle. 
         FIGS. 20-23  show different views of the suture head assembly attached to the elongated barrel via a rotation rod. The primary fixation point of the suture head assembly to the elongated barrel is depicted as being at the axis of lateral rotation.  FIG. 20  shows a side view of the suture head assembly. 
         FIG. 21  shows a bottom view of the suture head assembly. 
         FIG. 22  shows a bottom view of the suture head assembly articulated to the left. 
         FIG. 23  shows a bottom view of the suture head assembly articulated to the right. 
         FIGS. 24 and 25  are perspective views of a suturing device.  FIG. 24  shows a perspective view of the suturing device with the handles in the open position. 
         FIG. 25  shows a perspective view of the suturing device with the handles in the closed position. 
         FIG. 26  is a segmented assembly view of the suture head assembly of  FIGS. 24 and 25 . 
         FIGS. 27A and 27B  are cutaway segmental views of the suture head assembly of  FIGS. 24 and 25  showing interaction points of a suturing needle with a portion of the drive mechanism.  FIG. 27A  shows the position of the suturing needle and drive mechanism in a “home” position prior to use or after a complete full cycle.  FIG. 27B  shows another view of the suturing needle and drive mechanism. 
         FIG. 28  is a close-up view of the needle holder assembly for the suture head assembly of  FIGS. 24 and 25 . 
         FIG. 29  is a close-up view of the distal end of the suture head assembly of  FIGS. 24 and 25 . 
         FIGS. 30 and 31  show the suture head assembly of  FIGS. 24 and 25 .  FIG. 30  shows the suture head assembly with the latch in the open position. 
         FIG. 31  shows the suture head assembly with the latch in the closed or locked position. 
         FIG. 32  is a view of a curved suturing needle with notches on the face of the suturing needle to be used with the suturing device of  FIGS. 24 and 25 . 
         FIG. 33  shows a view of the pawl in contact with the suturing needle for the suturing device of  FIGS. 24 and 25 . 
         FIGS. 34 and 35  show a close-up view of the suture head assembly of  FIGS. 24 and 25  and the associated pulleys that move the drive mechanism.  FIG. 34  shows a top view of the suture head assembly. 
         FIG. 35  shows a side view of the suture head assembly. 
         FIGS. 36 and 37  are top views of the suture head assembly and cables that connect the drive mechanism located in the suture head assembly and the elongated barrel when the handle is in the open position for the suture device of  FIGS. 24 and 25 .  FIG. 36  shows a top view of the front pulley and cable when the handle is in the open position. 
         FIG. 37  shows a top view of the return pulley and cable when the handle is in the open position. 
         FIG. 38  shows a side elevational view of the suturing device of  FIGS. 24 and 25  showing parts of the drive mechanism. 
         FIG. 39A  shows a top perspective view of a second embodiment of the suture head assembly made in accordance with the teachings of the invention, in which a resilient elongated member moves proximally and distally to actuate movement of the suturing needle about a circular path.  FIG. 39B  depicts the suturing head of  FIG. 39A  incorporated into a suturing device having a flexible steerable proximal segment. 
         FIG. 40  shows a sectional view of the drive track of the second embodiment of the suture head assembly, depicting the course of the drive tendon, the drive pawl, and the anti-rotate spring in relation to the suturing needle. 
         FIG. 41  is a close-up view of the distal end of the drive tendon with attached pawl. 
         FIG. 42A  is an isolated view of the tendon and pawl engaging a notch in the suturing needle 
         FIG. 42B  is an isolated view of an exemplary suturing needle that may be used with the second suturing head embodiment, showing a leading notch and a trailing notch on the side of the needle, and an anti-rotate notch on the outer circumference of the needle. 
         FIG. 43  is a sectional view of the inside structure of the drive track component of the second embodiment of the suture head assembly, without the tendon, pawl, anti-rotate spring and needle present to highlight the engagement and disengagement tracks, including a flat spring in the proximal chamber used to press the pawl against the drive notch of the needle. 
         FIG. 44  is a perspective view of a portion of the inside structure of the needle track component of the second embodiment of the suture head assembly, showing one of the pawl body guides, and the aperture through which the anti-rotation spring engages the outer circumference of the needle. 
         FIG. 45  is a top perspective view of the second embodiment of the suture head assembly, showing the placement of the thrust collar over the lateral side of the needle track, enclosing the needle within it. 
         FIG. 46A  is a sectional view through the upper portion of the second embodiment of the suture head assembly, revealing the cross-section of the pawl as it engages the trailing notch of the needle, and showing the distal ends of both pawl body guides, separating the engagement track from the disengagement track. The relationship of the thrust collar to the needle and needle track is also apparent. 
         FIG. 46B  is a view of the thrust collar in isolation. 
         FIG. 47  is a sectional view of the second embodiment of the suture head assembly showing the pawl body positioned against the flat spring, which urges the pawl tip against the side of the needle. In this view, the needle is partially spanning the aperture of the suture head assembly, and the anti-rotate spring is visible as it contacts the outer circumference of the needle. 
         FIG. 48  is an isolated view of the anti-rotate spring. 
         FIG. 49  is an isolated view of the flat spring, which presses against the pawl body to urge the pawl tip against the side of the needle. 
         FIG. 50A  is a sectional view of the second embodiment of the suture head assembly in which the pawl is at the proximal end of the engagement drive track, immediately proximal to the trailing notch of the needle. 
         FIG. 50B  is a view through section B-B of  FIG. 50A  showing the pawl tip pressed against the side of the needle above the notch by a compressed flat spring. 
         FIG. 50C  is a top view through section C-C of  FIG. 50A  showing how the flat spring is deflected, pressing the pawl against the side of the needle. 
         FIG. 51A  is a sectional view of the second embodiment of the suture head assembly in which the pawl is within the trailing notch of the needle at the proximal end of the engagement drive track. 
         FIG. 51B  is a view through section B-B of  FIG. 51A  showing how the flat spring is relaxed against the pawl when the pawl tip is within the notch of the needle. 
         FIG. 51C  is a top view through section C-C of  FIG. 51A  showing the flat spring in a non-deflected state with the pawl tip advanced within the notch of the needle, now in position to drive the needle forward. 
         FIG. 52  is a sectional side view of the second embodiment of the suture head assembly, showing the needle in the ‘home’ position, the anti-rotate spring engaging the needle, and the pawl within the trailing notch, in position to drive the needle through a suturing cycle. 
         FIG. 53  is a sectional side view of the second embodiment of the suture head assembly, showing the needle at the end of the push stroke of the first suturing cycle, the pawl having pushed the needle through the aperture, and ready to disengage from the trailing notch. 
         FIG. 54  is a sectional side view of the second embodiment of the suture head assembly, showing the pawl being released from the trailing notch into the distal end of the disengagement track. 
         FIG. 55  is a sectional side view of the second embodiment of the suture head assembly, showing the pawl being pulled by the tendon to the proximal end of the track in the pull stroke of the first suturing cycle. 
         FIG. 56  is a sectional side view of the second embodiment of the suture head assembly, showing the pawl approaching the proximal chamber where the proximal ends of the engagement and disengagement tracks merge. The distal end of the tendon has been deflected away from the leading notch of the needle. 
         FIG. 57  is a sectional side view of the second embodiment of the suture head assembly, showing the pawl being released into the leading notch of the needle by spring force from the distal tendon that had been deflected as shown in  FIG. 56 . 
         FIG. 58  is a sectional side view of the second embodiment of the suture head assembly, showing the push stroke of the second suturing cycle, in which the pointed end of the needle is being advanced to the ‘home’ position by the pawl. 
         FIG. 59  is a sectional side view of the second embodiment of the suture head assembly, showing the push stroke of the second suturing cycle having been completed, the pawl being urged into the distal end of the disengagement track by the spring force of the distal tendon, and the trailing notch in proper alignment with the proximal chamber. 
         FIG. 60  is a sectional side view of the second embodiment of the suture head assembly, showing the pull stroke of the second suturing cycle, bringing the pawl back to the proximal end of the disengagement track to be positioned to re-initiate the suturing cycle. Backward rotation of the needle is prevented in this stroke by the anti-rotate spring engaging the anti-rotate notch of the needle. 
         FIGS. 61-71B  describe a further embodiment of a device made in accordance with the invention. 
         FIGS. 72-85  describe still a further embodiment of a device made in accordance with the invention. 
     
    
    
     While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments. 
     DETAILED DESCRIPTION 
     The suturing device of the presently disclosed embodiments is shown generally at  50  in  FIG. 1 . Referring to  FIG. 1 , the suturing device  50  can be used to produce a continuous or interrupted stitch or suture so as to enable closure of openings internal to a patient&#39;s body. The suturing device  50  can be utilized to suture any type of anatomical tissue in any type of anatomical cavity; and, accordingly, while the device  50  is described hereinafter for use with a cannula in endoscopic procedures, such as laparoscopy, the device  50  can be used in open surgery and with catheters and other small and large diameter tubular or hollow, cylindrical members providing access to small cavities, such as veins and arteries, as well as large cavities, such as the abdomen. 
     In an embodiment suturing device  50  includes an actuator mechanism shown generally at  52  which comprises an elongated barrel  54  and a handle  60  that extends from the undersides at a proximal end of the elongated barrel  54 . A suture head assembly  56  is attached to the distal end of the elongated barrel  54 . In an embodiment, the suture head assembly  56  is removably attached to the distal end of the elongated barrel  54 . The length of the suture head assembly  56  can range from about 20 mm to about 100 mm. In an embodiment, the length of the suture head assembly  56  is about 50 mm. The length of the elongated barrel  54  can range from about 50 mm to about 400 mm. Those skilled in the art will recognize that the elongated barrel  54  can be made shorter or longer depending on the intended use of the device  50 . In an embodiment, the elongated barrel  54  is about 300 mm. In an embodiment, the elongated barrel  54  is about 350 mm. An articulation lever  66 , just distal to the top of the handle  60  is pushed or pulled to cause the suture head assembly  56  to rotate. Moving the articulation lever  66  clockwise, moves the suture head assembly  56  to the right and moving the articulation lever  66  counterclockwise, moves the suture head assembly  56  to the left. The articulation lever  66  can also be moved to articulate the suture head assembly  56  up and down. The suture head assembly  56  is locked in place with a locking lever  64  located on an underside of the device  50 , below the articulation lever  66 . The suture head assembly  56  may be articulated, and the elongated barrel  54  may be any length appropriate for the intended clinical application of the device  50 . The diameter of the device  50  can range from about 3 mm to about 20 mm. In an embodiment, the diameter of the device  50  is about 12 mm. In an embodiment, the diameter of the device  50  is about 3 mm. A flush port  62  is located on the side of the elongated barrel  54  in order to provide a port of entry for cleaning fluids or suction such that the device  50  can be cleaned prior to or after use. 
     The handle  60  is a grip that is squeezed in order to actuate the suturing device  50 . The suturing device  50  is actuated by the actuator mechanism  52  coupled to a drive mechanism  70 . The actuator mechanism  52  of the suturing device  50  may comprise a triggering mechanism that is known in the art, such as for example, the triggering mechanisms disclosed in U.S. Pat. Nos. 6,053,908 and 5,344,061, both of which are hereby incorporated by reference. Alternatively, the actuator mechanism can be either a manually operable button or switch, or a mechanically operable by an automated electrical or a fuel driven device, such as for example, an electrical, electromagnetic or pneumatic motor powered by electrical, electromagnetic, compressed air, compressed gas, hydraulic, vacuum or hydrocarbon fuels. Those skilled in the art will recognize that any actuator mechanism of any type known in the art can be within the spirit and scope of the presently disclosed embodiments. 
     The suturing needle (e.g.,  120 ,  220 ) used with the suturing device  50  has an engagement or gripping surface at one or more locations along its length. By way of this surface, an engagement mechanism in the suture head assembly  56  can grip the needle to advance it through the target tissue. This gripping surface can take on a number of different forms, including, for example, one or more serrations or teeth raised above or depressed below the generally toroidal surface of the suturing needle, and properly oriented to allow the suturing needle to advance smoothly through tissue. In this case, the engagement mechanism in the suture head assembly  56  can include one or more number of interfitting teeth. The gripping or engagement surface of the suturing needle can also take the form of hatch marks engraved on the surface of the suturing needle, which either may be raised above or depressed slightly below the surface of the suturing needle. In this embodiment, the engagement mechanism in the suture head assembly  56  can comprise a rubberized contact surface, or a collapsible mesh that can surround the body of the needle at the gripping surface to apply a trapping force against the needle. 
     In a preferred embodiment, the gripping surface may include one or more notches that penetrate the surface of a suturing needle that is generally toroidal in shape, with the notches located on the outer circumference, inner circumference, or on one or both sides of the suturing needle. A corresponding engagement mechanism in the suture head assembly  56  can comprise a pawl, which can take many forms, but which at a minimum must effectively contact the leading or forward wall of a notch on the suturing needle, either to drive the needle in a forward direction, or to prevent the needle from moving in a reverse direction. The following description uses a particular embodiment of the gripping surface for illustrative purposes, and is not intended to limit the scope of the invention illustrated herein. 
       FIG. 2A  is a perspective view of the suture head assembly  56  with a cartridge holder assembly  90  located at the distal end to which a cartridge  88  can be attached. In accordance with one embodiment, the suture head assembly  56  may be fabricated as a single piece.  FIG. 2B  is a perspective assembly view of the suture head assembly of the presently disclosed embodiments showing part of the drive mechanism  70 , shown as a gear train/pulley system including pulleys  72 ,  74 ,  76  and  78 . Located within the elongated barrel  54  are mechanical parts including drive shafts, belts, rods, cables, or hydraulic tubes which run from the elongated barrel  54  through the spherical portion  58  and then engages with the drive mechanism  70  in the suture head assembly  56 . Connected at the proximal end of the suture head assembly  56  there is depicted a spherical portion  58  that contains part of the drive mechanism  70  including two idler pulleys  80  and cables  84  and  86 . The spherical portion  58  resides within the distal portion of the elongated barrel  54  and rotates in a substantially frictionless fashion. In one embodiment, the drive mechanism  70  includes a gear train/pulley system (“locomotive-type” drive mechanism) and cables and rods that extend from the distal end of the suture head assembly  56  to the proximal end of the elongated barrel  54 . 
     The suture head assembly  56  is that portion of the device  50  within which the mechanism for driving the curved needle  120  in a complete 360-degree circular arc, as well as the cartridge holder assembly  90  for attaching and releasing the cartridge  88  are situated. The suturing device  50  is unique in the fact that the orientation of the suture head assembly  56  is such that when the cartridge  88  is attached to the suture head assembly  56  the needle  120  is driven in a curved path about an axis approximately perpendicular to the longitudinal axis of the device  50 . In this way, the needle  120  may be optimally visualized as the needle  120  is driven in a circular arc. Also, as shown in  FIG. 2B , the needle  120  and cartridge  88  are in a plane parallel to the drive mechanism  70  and fit into the same space in the suture head assembly  56 . 
     The improved visibility offered by the shape and configuration of the suture head assembly  56  enables precise device placement over the incision or other target tissue of interest, and uniform advancement of the suturing device  50  after every stitch to provide a uniform and symmetric suture, thereby minimizing the risk of tearing tissue and bleeding due to a stitch being positioned too close to the edge of the incised tissue. In one embodiment, the entire device  50  or parts of the device  50 , such as the suture head assembly  56 , the elongated barrel  54 , the handle  60 , and the needle  120  and cartridge  88 , may be composed of a sterilizable medical grade plastic material, in which case, the entire device  50  or parts of the device  50  may discarded and disposed after a single use. In another embodiment, the device  50  may be composed of a sterilizable medical grade metallic material such as stainless steel to enable reuse subsequent to sterilization following a prior use. In still another embodiment, the device  50  is composed of a sterilizable medical grade metallic material such as titanium to enable reuse subsequent to sterilization following a prior use. The use of titanium is ideal for certain procedures including Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) because they are X-Ray radiolucent and do not interfere with MRI and CT scans. 
       FIGS. 3A and 3B  provide detailed segmental views of the suture head assembly  56  showing the cartridge holder assembly  90 , the disposable needle cartridge  88 , a curved suturing needle  120 , and parts of the drive mechanism  70  including a plurality of pulleys,  72 ,  74 ,  76 ,  78  and  80  involved in driving the needle driver  98  through a semicircular path. In one embodiment, the needle driver is a pawl  98 . As depicted, a shoulder screw  108  is used to keep a latch  110  locked in place over the disposable cartridge  88  and the suturing needle  120 . Pulleys  72 ,  74 ,  76  and  78  are engaged with an actuator arm  102 , which is attached to the pawl  98 . The pawl  98  interfits with two notches  132  (as depicted in  FIG. 15 ) located on the needle  120  at 180 degrees apart from each other which drives the curved needle  120  in a completely circular arc. The suture head assembly  56  is preferably configured so that the pawl  98  (or other needle driver), does not intrude into or obstruct the area within the curve of the needle  120 . The entire area within the circular arc of the needle  120  is unobstructed; there is no hub at the center of the circular arc so that the device  50  can encompass the maximum volume of tissue within the circular arc of the curved needle  120 . In this way, the needle  120  may be rotated through a relatively large arc, allowing the needle  120  to obtain a sufficient “bite” into the tissue. Preferably, the needle  120  will have a radius of curvature of about 3 mm to about 40 mm. In an embodiment, the device  50  sutures within the limit of the diameter of the suture head assembly  56 , which is advantageous to suturing through small cannulas during minimally invasive surgery. In an embodiment, the diameter of the curved needle  120  does not exceed the diameter of the suture head assembly  56 . 
       FIGS. 4A and 4B  show detailed views of the drive mechanism  70  located in the suture head assembly  56  with respect to driving the needle  120  during use of the device  50  (the cartridge housing  88  has been removed to show the drive mechanism  70  in detail). The drive mechanism  70  includes a plurality of pulleys,  72 ,  74 ,  76  and  78 , and the associated axle pins  82 , involved in driving the pawl  98  through a semicircular path. The actuator arm  102  engages pulleys  72  and  76  and are pinned  75  to pulleys  72  and  76 . As pulleys  76  and  78  rotate with the motion of the cables  86  and  84 , respectively, which reside in the elongated barrel  54  (not shown), pulley  74  acts as an idler pulley, transferring the motion to the most distal pulley  72 . Pulley  72  and pulley  76  rotate through identical arcs. The actuator arm  102  provides a connection to the pawl  98 . The pawl  98  is located in the distal end of the actuator arm  102 . The pawl  98  is attached to the actuator arm  102  by an integral shaft and collar  100  that fits loosely into the actuator arm  102  allowing smooth movement. As the handle  60  is closed and opened, the pawl  98  moves through the same arc as pulleys  72  and  76 . The pawl  98  at the distal end of the actuator arm  102  is capable of engaging the notches  132  located along the radially inner edge of the needle  120 . The actuator arm  102  is activated by the user upon squeezing of the handle  60 , and is capable of sweeping back and forth in an arc spanning about 190 degrees or more.  FIG. 4A  shows a detailed view of the drive mechanism  70  and the suturing needle  120  either prior to using the device  50  or after one complete full cycle of the device  50 .  FIG. 4B  shows a detailed view of the drive mechanism  70  and the suturing needle  120  after one squeeze of the handle  60 . As shown, the drive mechanism  70  has moved in a circular arc greater than about 180 degrees, (about 190 degrees), while the suturing needle  120  has moved in a circular arc of about 190 degrees to drive through the tissue or vessel to be sutured. 
     The outer surface of the actuator arm  102  is shaped to accommodate a C-brace (shown as  106  in  FIG. 7 ) that causes the pawl  98  to engage the needle  120  and thereby remain in contact. The advancing movement of the needle  120  during operation causes the notches  132  along the radially inner edge of the needle  120  to align with the pawl  98  in the actuator arm  102 , thereby causing the pawl  98  to engage the notches  132  due to a positive pressure exerted by the C-brace (not shown), and to “lock” into the notches  132 . The rotary advancing movement of the needle  120  is therefore controlled to occur sequentially through about 190 degrees each time the needle is actuated. 
       FIG. 5A  shows a close-up view of the distal end of the suture head assembly  56  with the cartridge  88  and the needle  120  in view as well as the relationship between the pawl  98  and the actuator arm  102  with respect to the needle  120 . The needle  120  is enclosed within the cartridge  88 , so the sharp pointed end  124  is not exposed. This needle position, as loaded, is referred to as the “home” position ( FIG. 5A ). In the home position, the needle  120  is fully contained within the cartridge housing  88  to eliminate needle-pricks during handling of the cartridge  88  or the loaded device. Squeezing the device handle  60  fully, two times, operates the device  50  through one full cycle. As shown in  FIG. 6A , the first full actuation of the handle  60  drives the needle  120  through an about 190 degree arc. The pointed end of the needle  124  exits the protective enclosure of the cartridge  88 , drives through the tissue to be sutured, and re-enters the protection of the cartridge  88  of the device  50 . This position, after the first squeeze of the handle  60 , is referred to as the “rotation” position. As shown in  FIG. 6B , the handle  60  is then released, and the needle  120  remains in the rotation position while the pawl  98  and the actuator arm  120  return to their start position. The handle  60  is then squeezed again driving the needle  120  through an about 190 degree arc and returning the needle  120  to the home position. 
       FIG. 5A  shows the needle  120  in the home position, the pawl  98  is engaged in the notch  132  near the suture end of needle  126 . An anti-rotate spring  136  is engaged in the notch  134  on the outer surface of the needle  120 , not allowing the needle  120  to move backwards in the cartridge  88  of the device  50 . A close-up view of the anti-rotate spring  136  is shown in  FIG. 5B . In an embodiment, the needle  120  comprises at least one anti-rotate notch  134  and is engaged with at least one anti-rotate spring  136 . As the pawl  98  drives the needle  120  through a first semi circular arc, the anti-rotate spring  136  slips out of the notch  134  and slides over the outer surface of the needle  120 . As the pawl  98  reaches the end of a first drive stroke, the anti-rotate spring  136  snaps in behind the rear corner of the needle  120 , near the suturing material or thread  146  (see  FIG. 6A ). As the pawl  98  returns to the start position, the anti-rotate spring  136  holds the needle  120  in place, preventing the needle  120  from moving with the pawl  98  back toward the start position. The pawl  98  returns to the start position and engages the notch  132  in the needle  120  near the pointed end  124  (see  FIG. 6B ). When the handle  60  is squeezed a second time, the needle  120  is driven back to the home position. 
     The width of the aperture  118  in the cartridge  88  is comparable to and corresponds with the width of the gap in the needle  120  so that when the needle  120  is in the home position (as shown in  FIG. 5A ) the needle  120  does not project materially into the aperture  118 . Such an alignment causes the needle  120  to reside entirely within the cartridge  88 , thereby preventing inadvertent contact of the sharp pointed end  124  with the user&#39;s fingers during handling of the disposable needle cartridge  88  for placement on the cartridge holder assembly  90  or disposal after use, and while operating the suturing device  50 . Such protection of the needle  120  in the suturing device  50  prevents accidental “needle-pricks” from occurring, thereby substantially reducing the risk of infection caused by pathogenic bacteria or viruses that may contaminate the needle  120  during or after use prior to disposal. The needle  120  may be rotated in a curved track  92  of the cartridge  88  about the longitudinal axis of the suturing device  50  to advance the pointed needle end  124  so that the needle  120  first spans the aperture  118  and then returns to the home position. The suturing material or thread  146  is attached to the needle  120 , and therefore follows the path of the needle  120 . The suturing material or thread  146  may then be cut and secured by an appropriate method, such as for example, by tying, or additional stitches may be placed along the entire wound or incision by repeating the aforementioned process. Every stitch, whether a single, interrupted stitch, or one of a series of continuous, running stitches may be placed in like manner. The suturing device  50 , therefore, may be used to insert either a single stitch, or to insert a suture comprising a plurality of continuous stitches as a replacement method for a more tedious and time-consuming manual suturing process. The terminal end of the suturing material or thread  146  may contain a knot or button to prevent the suturing material or thread  146  from pulling through the sutured tissue during placement of the first stitch. In an embodiment, the cartridge  88  comprises the suturing needle  120  attached to the terminal end suturing material or thread  146 , and an appropriate length of suturing material or thread  146  are all packaged in a sterilizable medical packaging material. 
       FIG. 7A  shows a close-up view of the pawl  98  which rides in a track formed by the C-brace  106  and the suture head assembly  56 . The pawl  98  is spring loaded with a spring  104 . The spring  104  is engaged to the tip of the pawl  98   b  as shown in  FIG. 7A . The spring  104  engages the pawl tip  98   b  into the notch  132  in the needle  120  during the driving stroke of the device  50  when the handle  60  is closed. The spring  104  also allows the tip of the pawl  98   b  to rotate out of notch  132  of the needle  120  during the return of the pawl  98  to the start position when the handle  60  is opened. The heel of the pawl  98   a  stays in contact with the C-brace  106  during the driving stroke of the device  50 , preventing the pawl  98  from over-rotating and locking the needle  120 .  FIG. 7B  shows a close-up view of the pawl  98  showing the pawl heel  98   a  and the pawl tip  98   b.    
     Referring now to  FIGS. 8 and 9  in conjunction with  FIG. 1 , the user introduces the distal end portion of suturing device  50  into a body cavity, via a cannula assembly (not shown), and then laterally articulates the suture head assembly  56  using the articulation lever  66  located just distal to the top of the handle  60 . The suture head assembly  56  is then positioned relative to the tissue/vessel to be sutured, and the user locks the suture head assembly  56  in place using the locking lever  64 . The user then, through manipulation of suturing device  50 , positions a plurality of separated tissue segments into the opening defined at the distal end portion of the suture head assembly  56  and within the aperture of the cartridge  118 . The user, using only one hand, may manipulate the device  50  while actuating the handle  60  to close an incision with a continuous suture whose stitches may be individually tensioned precisely and uniformly along the length of the suture similar to suturing done by hand in the conventional way. The user may employ a single suture which would extend the entire length of the incision or multiple sutures. 
     The device  50  starts with the needle  120  in the home position and the handle  60  fully open (see  FIG. 8 ). In an embodiment, the handle  60  is made up of a grip which rests in the user&#39;s palm and is squeezed in order to actuate the device  50 . To drive the needle  120  through the tissue to be sutured, the user squeezes the handle  60  moving the needle  120  from the home position to the rotation position. The handle  60  contains linkages  144  to both the upper drive rod  142  and the lower drive rod  140 . Squeezing the handle  60  (see  FIG. 9 ) causes the two drive rods  140  and  142  to move in opposite directions. The upper drive rod  142 , moves forward while the lower drive rod  140  moves backward. The drive rods are connected to the suture head assembly  56  with cables  84  and  86  and idler pulleys  80 . The upper rod  142  is connected to pulley  78  with cable  84 . The lower rod  140  is connected to pulley  76  with cable  86 . 
       FIGS. 10 and 11  in conjunction with  FIG. 8 , show the connections and positions of cables  84  and  86  and the drive pulleys  72 ,  74 ,  76  and  78  when the handle  60  is in the open position.  FIGS. 12 and 13  in conjunction with  FIG. 9 , show the connections and positions of cables  84  and  86  and the drive pulleys  72 ,  74 ,  76  and  78  when the handle  60  is in the closed position. The force to move needle  120  from the home position to the rotation position comes from the lower rod  140  pulling backward on the drive cable  86 . The lower rod  140  extends nearly the full length of the elongated barrel  54 , connecting to drive cable  86 , at the proximal end of the elongated barrel  54 . As shown in  FIG. 11 , cable  86  exits the elongated barrel  54  and enters the suture head assembly  56 , passing over an idler pulley  80  located in the spherical portion  58 , then wrapping clockwise (as viewed from the bottom) around pulley  76  and is secured to pulley  76  located in the suture head assembly  56 . The pulling action of cable  86  causes pulley  76  to rotate through an arc of approximately 190 degrees. As lower rod  140  pulls backward, the upper rod  142  moves forward. The upper rod  142  also extends nearly the full length of the elongated barrel  54 , connecting to drive cable  84 , at the proximal end of the elongated barrel  54 . As shown in  FIG. 10 , cable  84  also exits the elongated barrel  54  and enters suture head assembly  56 , passing over a second idler pulley  80  located in the spherical portion  58 , then wrapping (clockwise as viewed from the top) around pulley  78  and is secured to pulley  78  located in the suture head assembly  56 . Pulley  78  is directly linked to pulley  76  through the actuator arm  102 , and cables  84  and  86  are wrapped in opposing directions, so that as cable  86  unwinds from pulley  76 , cable  84  winds onto pulley  78 . 
     The needle  120  is held in a path of rotation by a combination of three components. The cartridge  88 , the C-brace  106  and the cartridge holder assembly  90  interact to constrain the needle  120  to the path of rotation (see  FIG. 5 ). The cartridge  88  is a semicircular shaped component that is held into the device  50  by a plurality of extensions  94  located on each end of the cartridge  88  (see  FIGS. 14 and 15 ). In an embodiment, the plurality of extensions  94  takes the form of tabs. In an embodiment, the cartridge  88  is made from a sterilizable medical grade metallic material such as stainless steel. The cartridge  88  provides some of the support structure for keeping the needle  120  in a rotational path and therefore should be constructed from a material with structural integrity. Those skilled in the art will recognize that any high-strength medical grade material may be used to fabricate the cartridge  88 , such as a high-strength plastic. In an embodiment, the plurality of extensions are tabs extending from the cartridge housing  88 . The plurality of extensions  94  lock into mating grooves  96  located along on the distal edge of the cartridge holder assembly  90  that are located diametrically opposite to one another, and are capable of engaging the plurality of extensions  94  correspondingly located in the needle cartridge housing  88  as shown in  FIG. 16 . 
     The proximal end of cartridge  88  is held in place by a cartridge holder assembly  90 , as shown in  FIG. 17A . The cartridge holder assembly  90  also includes a latch  110 , a lever  112 , associated pins  114  and  116 , a shoulder screw  108 , an anti-rotate spring  136  and at least one groove  96  that can engage with the plurality of extensions  94  located on the cartridge  88 . It is the interaction of all of the elements of the cartridge holder assembly  90  that hold and lock the cartridge  88  in place. The latch  110  slides back to release the cartridge  88  and forward to lock the cartridge  88  in place. The latch  110  also has a built into ejector feature, as shown in  FIG. 17B . A lever  112  is located distal and below the needle  120  and the cartridge  88 . The lever  112  pivots on a pin  114 . A second pin  116  located above the pivot pin  114 , engages with a slot in the latch  110 . To release the needle  120  and the cartridge  88 , the latch  110  is pulled back and the lever  112  is rotated up and back, causing pin  116  to move back with the latch  110  and to rotate about pin  114  thus pushing the needle  120  and the cartridge  88  from the cartridge holder assembly  90 . The needle  120  and the cartridge  88  are then removed from the device  50  by a slight proximal motion to disengage the plurality of extensions  94  from their mating grooves  96  in the cartridge holder assembly  90 .  FIG. 17C  shows the needle  120  as it is driven through a first semi circular arc (the handle  60  has partially completed a first full squeeze). As the pawl  98  drives the needle  120  through a first semi circular arc, the anti-rotate spring  136  slips out of the notch  134  and slides over the outer surface of the needle  120 . 
     Loading of the needle  120  and the cartridge  88  is accomplished by engaging the plurality of extensions  94  into both grooves  96  on the cartridge holder assembly  90  and then pressing the proximal ends down against the sloped distal surface of the latch  110 . The latch  110  is spring loaded at the proximal end, thus can slide back as the needle  120  and the cartridge  88  are pressed into place and then snap closed to the locked position, retaining the needle  120  and the cartridge  88 . The lever  112  is down and out of the way of the operation of the needle  120  and the cartridge  88 . 
       FIG. 18  shows a close-up view of the needle  120 . The two notches  132  are located about 180 degrees apart on the inner surface and assist in driving the needle  120 . The pawl  98  engages the notches  132  when driving the needle  120  through the circular motion. A third notch  134  is located on the outer surface of the needle  120 . The notch  134  assists in preventing rotation of the needle  120  and provides an anti-rotation feature. In an embodiment (see  FIGS. 19A and 19B ), the needle  120  is formed as a circular split ring with a gap  122 , a sharp, pointed end  124 , and a blunt end  126 . The needle  120  further comprises an opening  130  to accommodate the leading end of the suturing material or thread  146 . In one embodiment, the opening  130  is the form of an eye though which the leading end of the suturing material or thread  146  may be passed through for attachment to the needle  120 . In the illustrated needle  120  ( FIG. 19A ), the opening  130  is located adjacent to the blunt end  126 . The opening  130  however, can be positioned anywhere along the arc or the needle  120  between the apex  128  and the blunt end  126 . In another embodiment ( FIG. 19B ), the needle  120  comprises an opening  130  in the form of a cylindrical bore aligned axially with respect to the needle  120 , located at the blunt end  126  ( FIG. 19B ). The leading end of the suturing material or thread  146  is inserted into the opening  130  and restrained by mechanically crimping. To enable the needle  120  to penetrate tissue to a required depth, the arc length of the needle  120  is preferably about 240 degrees to about 300 degrees. The needle  120  comprises two symmetric notches  132  along the radially inner edge (“inner notches”) that are positioned proximally to the sharp, pointed end  124  and the blunt end  126  of the needle  120 . The notches  132  are located directly opposite to each other, each having a perpendicular (about 90 degree) segment and an angular segment that makes an angle of about 60 degrees with the perpendicular segment. The inner notches  132  are engaged by the needle driver  98  of the drive mechanism  70  and enable the needle  120  to undergo a rotary movement upon actuation of the drive mechanism  70 , thereby causing the needle  120  to penetrate into and advance through tissue. A similar triangular notch  134  is located on the radially outer edge (“outer notch”) of the needle  120  proximally to the inner notch  132  closer to the sharp, pointed end  124 . The outer notch  134  engages with the anti-rotate spring  136  located on the cartridge holder assembly  90 , whereby rotation of the needle  120  in a direction opposite to the advancing direction or “needle backing-up” is prevented. The positive engagement of the needle outer notch  134  during operation of the suturing device precludes needle  120  from straying out of sequence during the suturing process. 
     The suture head assembly  56  of the device  50  can be laterally articulated to the left of center and also to the right of center. In one embodiment, the suture head assembly  56  can be laterally articulated through an arc of about 22.5 degrees to the left of center and also to the right of center, for a total of about 45 degrees or more. In addition, the suture head assembly can be articulated up and down. In one embodiment, the suture head assembly  56  can be articulated up and down. The ability of the suture head assembly  56  to be articulated to the left and right of center, as well as up and down, permits the user to position the suture head assembly  56  for many different types of suturing applications. The articulation lever  66 , just distal of the top of the handle  60 , is pushed or pulled to cause the suture head assembly  56  to rotate. Viewed from above, moving the articulation lever  66  clockwise moves suture head assembly  56  to the right and moving the articulation lever  66  counterclockwise moves suture head assembly  56  to the left. The suture head assembly  56  is locked in place with the locking lever  64  located on the bottom of the device  50 , below the articulation lever  66 . Movement is accomplished using the solid articulation rod  68  to link the articulation lever  66  to the suture head assembly  56 . The articulation rod  68  is pinned to the articulation lever  66  and to one side of the most proximal section of the suture head assembly  56  so that the articulation rod  68  pushes or pulls the suture head assembly  56  through a full range of motion (see  FIGS. 20-23 ). 
       FIGS. 20-23  show the articulation rod  68  in the elongated barrel  54  and the connection to the suture head assembly  56 . The suture head assembly  56  is shown moving from left articulation, to straight to right articulation (some components are not shown to allow clear viewing of the linkage).  FIG. 20  shows a side view of the suture head assembly  56 .  FIG. 21  shows a bottom view of the suture head assembly  56  with no articulation.  FIG. 22  shows a bottom view of the suture head assembly  56  articulated to the left.  FIG. 23  shows a bottom view of the suture head assembly  56  articulated to the right.  FIGS. 20-23  show a number of items. The articulation rod  68  runs down the center of the elongated barrel  54  and is attached to one side of the spherical portion  58 . The function of the articulation rod  68  is to push and pull the suture head assembly  56  through an articulation. The two idler pulleys  80 , which drive cables  84  and  86  are located in the spherical portion  58 . Looking at  FIG. 20 , the two idler pulleys  80  seem to be one on top of the other. Instead however, they are located in plane with either pulley  76  and lower rod  140  or pulley  78  and upper rod  142 . 
     In accordance with one embodiment, the entire suturing device  50  can be designed as a single unit which may be either reusable or disposed after a single use. If desired, the entire suturing device  50  can be designed from a number of units which, each unit may be either reusable or disposed after a single use. 
     The suturing device  50  is preferably configured to provide a “pistol like” grip for the user that includes an elongated barrel  54  and a handle  60  that extends from the proximal end of the elongated barrel  54 . The elongated barrel  54  has either a linear or non-linear configuration, including but not limited to, straight, curved and angled configurations. A suture head assembly  56  is removably attached to the distal end of the elongated barrel  54 . The suture head assembly  56  contains a portion of the drive mechanism  70  of the device  50 . The working end of the suture head assembly  56  has a cartridge holder assembly  90  to which a disposable cartridge  88  that is capable of accommodating a suturing needle  120  may reside. 
     The disposable cartridge  88  preferably has a generally cylindrical housing with an opening or aperture  118  in the sidewall of the housing at the distal or working end thereof. An arcuate suturing needle  120  having a sharp, pointed end  124  is slidably mounted in a circular track  92  of the cartridge  88 . A blunt end of the needle  126  is connected to a suturing material or thread  146 . The radius of the arc defining the arcuate suturing needle  120  is approximately equal to the circumference to the cartridge housing  88  at the aperture  118  therein. The needle  120  normally resides in a “home” position in the track  92  such that the gap in the arcuate suturing needle  122  is in alignment with the aperture  118  in the cartridge  88 . The sharp, pointed end of the needle  124  is situated on one side and entirely within the confines of the housing aperture  118 ; the pointed end of the needle  124  is, therefore, shielded by the cartridge housing  88 . The blunt end of the suturing needle  126  that is attached to the suturing material or thread  146  is located at the opposite side of the aperture  118 . The sharp, pointed end of the needle  124  is, therefore, wholly contained within the cartridge  88  and does not protrude beyond the housing of the cartridge  88 . Thus, the sharp pointed end of the needle  124  is not exposed to the user. 
     In accordance with the presently disclosed embodiments, the needle  120  may be releasably engaged by a needle driver  98  that is rotatably mounted within the suture head assembly  56  so that the needle  120  can be rotated from the home position by about 360 degrees about the central vertical axis of the cartridge  88 . Such a rotary action of the needle  120  causes the sharp point  124  to advance across the cartridge housing  88  so as to span the aperture  118 . Thus, when the device  50  is positioned such that the incised tissue segments to be sutured are situated at the housing aperture  118 , the needle  120  penetrates the tissue segments and spans the incision between them. A continued rotary movement of the needle  120  causes the needle  120  to return to the home position, and thereby causes the suturing material or thread  146  attached to the needle  120  to be pulled into and through the tissue in an inward direction on one side of the tissue incision, and upwards and out through the tissue on the opposite side of the incision. Thus, the suture material or thread  146  follows the curved path of the needle  120  to bind the tissues together with a stitch of material or thread  146  across the incision in a manner similar to manual suturing, wherein the needle  120  is “pushed” from the blunt end  126  and then “pulled” from the pointed end  124  by the pawl  98 . Preferably, an anchoring mechanism is provided at the trailing terminal end of the suturing material or thread  146  to prevent the material  146  from being pulled completely through and out of the tissue segments. For example, the anchoring mechanism can be a pre-tied or a welded loop, a knot wherein the suture material or thread  146  is simply tied, or a double-stranded, looped suture is that attached to the suturing needle  120 . The rotary movement of the needle  120  within the needle cartridge  88  is accomplished by a pawl  98  that may be operated by the user by holding the suturing device  50  with one hand in a pistol-like grip around the handle  60 , and using at least one finger of that hand to activate. 
     The suturing device  50  of the presently disclosed embodiments can be used for a laparoscopic procedure, including but not limited to laparoscopic colostomy, colectomy, adrenalectomy, splenectomy, repair of paraesophageal hernia, inguinal hernia repair, ventral hernia repair, Nissen fundoplication, liver lobectomy, gastrectomy, small bowel resection, treatment of small bowel obstruction, distal pancreatectomy, nephrectomy and gastric bypass. Those skilled in the art will recognize that the presently disclosed embodiments can be used in other laparoscopic procedures. 
     In using the device  50  of the presently disclosed embodiments, the abdomen is insufflated with gas to create a working space for the user. Any gas known to those skilled in the art including, but not limited to, nitrogen or carbon dioxide, can be used. Access portals are established using trocars in locations to suit the particular surgical procedure. A variety of surgical instruments may then be inserted into the body through these access ports/cannulas. The user then introduces the distal end portion of suturing device  50  into a cannula, and then laterally articulates the suture head assembly  56  using the articulation lever  66  located just distal to the top of the handle  60 . The suture head assembly  56  is then positioned relative to the tissue/vessel to be sutured together, and the user locks the suture head assembly  56  in place using the locking lever  64 . The user then, through manipulation of suturing device  50 , positions a plurality of separated tissue segments into the opening defined at the distal end portion of the suture head assembly  56  and within the aperture  118  of the cartridge  88 . The user, using only one hand, may manipulate the device  50  while actuating the handle  60  to close an incision with a continuous suture whose stitches may be individually tensioned precisely and uniformly along the length of the suture similar to suturing done by hand in the conventional way. The user may employ a single suture which would extend the entire length of the incision or multiple sutures. Thus, by placement of the device  50  with the needle cartridge aperture  118  spanning the incised tissue segments and actuating the handle  60 , the suturing device  50  enables the user to lay down a running stitch or interrupted stitch to close the tissue incision in a time efficient manner. Those skilled in the art will recognize that any conventional procedure for conducting laparoscopic surgery can be used with the device  50 . 
     The needle cartridge  88  is disposably mounted on a cartridge holder assembly  90  at the distal end of the suture head assembly  56 . The minimalized structural design of the suture head assembly  56  enables the user to have a clear, unobstructed view of the suturing needle  120  during advancement through the tissue segments during the course of a suturing operation, thereby enabling precise placement of the suturing device  50  to provide uniform sutures and precluding the risk of tearing tissue by placement too close to the edge of the incision. The suturing device  50  is then advanced a short distance along the incision and the aforementioned operation is repeated to produce another stitch comprising the suturing material or thread  146 . 
     The user may continue to manipulate the suturing device  50 , alternately advancing and actuating rotation of the needle  120  about an axis that is generally parallel to the direction of advancement to create a continuous suture which may extend through the entire length of the incision or a series of interrupted stitches. After each individual stitch is laid down, the stitch is tightened by exerting a pull on the suturing material or thread  146  so that the resultant suture is tensioned uniformly along the length of the incised tissue segments. Therefore, a tight closure of the segments is accomplished and bleeding and tearing of tissue are minimized. Once the appropriate amount of suture material or thread  146  has been placed, the user can use a needle grasper to tighten and knot the formed stitches. 
     The presently disclosed embodiments provide a method for suturing tissue during minimally invasive surgery including engaging a cartridge  88  to a suture head assembly  56  at a distal end of a suturing device  50 , the cartridge  88  having a protective housing and a suturing needle  120  with a pointed end  124  and a blunt end  126 ; introducing the distal end of the suturing device  50  into a body cavity; positioning an opening  118  in the cartridge  88  to span a plurality of separated tissue segments; activating an actuator  52  coupled to a drive mechanism  70  that engages the suturing needle  120  to cause rotational movement of the suturing needle  120  about an axis approximately perpendicular to a longitudinal axis of the suturing device  50  and advance the suturing needle  120  through the plurality of separated tissue segments; and pulling a suturing material  146  attached to the suturing needle  120  through the plurality of separated tissue segments forming a stitch. 
     The presently disclosed embodiments provide a method for suturing tissue during minimally invasive surgery including (a) engaging a cartridge  88  to a suture head assembly  56  at a distal end of a suturing device  50 , the cartridge  88  having a protective housing and a suturing needle  120  with a pointed end  124  and a blunt end  126 ; (b) introducing the distal end of the suturing device  50  into a body cavity; (c) positioning an opening  118  in the cartridge  88  to span a plurality of separated tissue segments; (d) activating an actuator  52  coupled to a drive mechanism  70  that engages the suturing needle  120  to cause rotational movement of the suturing needle  120  about an axis approximately perpendicular to a longitudinal axis of the suturing device  50  and advance the suturing needle  120  through the plurality of separated tissue segments; (e) pulling a suturing material  146  attached to the suturing needle  120  through the plurality of separated tissue segments forming a stitch and repeating steps (c) through (e) to cause a plurality of stitches to be placed through the separated tissue segments. 
     The presently disclosed embodiments provide a method for suturing tissue during minimally invasive surgery including inserting a distal end of a suturing device  50  having a suturing needle  120  with a pointed end  124  into a body; positioning the suturing needle  120  to span a plurality of separated tissue segments; activating an actuator  52  a first time causing the pointed end  124  of the suturing needle  120  to extend beyond a protective housing of a cartridge  88  to engage the plurality of separated tissue segments; activating the actuator  52  a second time to cause the suturing needle  120  to complete a revolution and pull a suture  146  extending from the suturing needle  120  through the plurality of separated tissue segments to form a stitch. 
     The suturing device  50  may be configured in different ways with respect to length and angle of the suture head assembly  56 . The size of the needle  120 , the needle cartridge  88 , the cartridge aperture  118  and the aperture position may also be varied for use in open surgery to perform procedures such as closing of the fascia, skin closure, soft tissue attachment, anastomosis, fixation of mesh, grafts and other artificial materials. 
       FIGS. 24 and 25  show an alternative embodiment of a suturing device shown generally at  150 . Referring to  FIGS. 24 and 25 , the suturing device  150  can be used to produce a continuous or interrupted stitch or suture so as to enable closure of openings internal to a patient&#39;s body. The suturing device  150  can be utilized to suture any type of anatomical tissue in any type of anatomical cavity; and, accordingly, while the device  150  is described hereinafter for use with a cannula in endoscopic procedures, such as laparoscopy, the device  150  can be used in open surgery and with catheters and other small and large diameter tubular or hollow, cylindrical members providing access to small cavities, such as veins and arteries, as well as large cavities, such as the abdomen. 
     In an embodiment, the suturing device  150  includes an actuator mechanism shown generally at  152  which comprises an elongated barrel  154  and a handle  160  that extends from the undersides at a proximal end of the elongated barrel  154 . Located within the elongated barrel  154  are mechanical parts including cables which run from the elongated barrel  154  through a spherical portion  158  and then engages with the drive mechanism in a suture head assembly  156 . The spherical portion  158  resides within the distal portion of the elongated barrel  154  and rotates with low friction. In an embodiment, a drive mechanism  170  includes a pulley system and cables that extend from the distal end of the suture head assembly  156  to the proximal end of the elongated barrel  154 . 
     The suture head assembly  156  houses the mechanism for driving a curved needle  220  in a complete 360 degree circular arc. The orientation of the suture head assembly  156  is such that when the needle  220  is attached to the suture head assembly  156  the needle  220  is driven in a curved path about an axis approximately perpendicular to the longitudinal axis of the device  150 . In this way, the needle  220  may be optimally visualized as the needle  220  is driven in a circular arc. Also, as shown in  FIGS. 24 and 25 , the needle  220  is in a plane parallel to the drive mechanism and fits into the same space in the suture head assembly  156 . 
     The improved visibility offered by the shape and configuration of the suture head assembly  156  enables precise device placement over the incision, and uniform advancement of the suturing device  150  after every stitch to provide a uniform and symmetric suture, thereby minimizing the risk of tearing tissue and bleeding due to a stitch being positioned too close to the edge of the incised tissue. In one embodiment, the entire device  150  or parts of the device  150 , such as the suture head assembly  156 , the elongated barrel  154 , the handle  160 , and the needle  220 , are composed of a sterilizable medical grade plastic material, in which case, the entire device  150  or parts of the device  150  may discarded and disposed after a single use. In an embodiment, the device  150  is composed of a sterilizable medical grade metallic material such as stainless steel to enable reuse subsequent to sterilization following a prior use. In another embodiment, the device  150  is composed of a sterilizable medical grade metallic material such as titanium to enable reuse subsequent to sterilization following a prior use. The use of titanium is beneficial for certain procedures including Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) because they are X-Ray radiolucent and do not interfere with MRI and CT scans. 
       FIG. 24  shows the handle  160  in an open position.  FIG. 25  shows the handle  160  in the closed position. The suture head assembly  156  is attached to the distal end of the elongated barrel  154 . In one embodiment, the suture head assembly  156  is removably attached to the distal end of the elongated barrel  154 . The length of the suture head assembly  156  can range from about 10 mm to about 100 mm. In a particular embodiment, the length of the suture head assembly  156  is about 40 mm. The length of the elongated barrel  154  can range from about 50 mm to about 400 mm. Those skilled in the art will recognize that the elongated barrel  154  can be made shorter or longer depending on the intended use of the device  150 . In one embodiment, the elongated barrel  154  is about 300 mm in length. In another embodiment, the elongated barrel  154  is about 350 mm in length. An articulation lever  166 , just distal to the top of the handle  160  is pushed or pulled to cause the suture head assembly  156  to rotate. Moving the articulation lever  166  clockwise moves the suture head assembly  156  to the right and moving the articulation lever  166  counterclockwise moves the suture head assembly  156  to the left. The articulation lever  166  can also be moved to articulate the suture head assembly  156  up and down, as desired. The suture head assembly  156  is locked in place with a locking lever  164  located on an underside of the device  150 , below the articulation lever  166 . The suture head assembly  156  may be articulated, and the elongated barrel  154  may be any length appropriate for the intended clinical application of the device  150 . The diameter of the device  150  can range from about 3 mm to about 20 mm. In one embodiment, the diameter of the device  150  is about 12 mm. In another embodiment, the diameter of the device  150  is about 3 mm. 
     The handle  160  may be a grip that is squeezed in order to actuate the suturing device  150 . The suturing device  150  is actuated by the actuator mechanism  152  coupled to a drive mechanism  170 . The actuator mechanism  152  of the suturing device  150  may comprise a triggering mechanism that is known in the art, such as for example, the triggering mechanisms disclosed in U.S. Pat. Nos. 6,053,908 and 5,344,061, both of which are hereby incorporated by reference. Alternatively, the actuator mechanism  152  can be either a manually operable button or switch, or mechanically operable by an automated electrical or a fuel driven device, such as for example, an electrical, electromagnetic or pneumatic motor powered by electrical, electromagnetic, compressed air, compressed gas, hydraulic, vacuum or hydrocarbon fuels. Those skilled in the art will recognize that any actuator mechanism of any type known in the art can be within the spirit and scope of the presently disclosed embodiments. 
       FIG. 26  provides an assembly view of the suture head assembly  156 . The suture head assembly  156  is fabricated from multiple pieces including a holder assembly  190 , a needle holder assembly  188 , a latch  210 , and parts of the drive mechanism  170  including a plurality of pulleys,  172 ,  174  and  176  and two idler pulleys  180  involved in driving a needle driver  198  through a semicircular path. Pulleys  172  and  174  may include a set of four pulleys, or two sets of pulleys, labeled  178 . In one embodiment, the needle driver is a pawl  198 . A shoulder screw  208  and a plurality of needle assembly extensions  194  may be used to keep the latch  210  locked in place over the needle holder assembly  188  and the suturing needle  220 . The needle holder assembly  188  includes a curved track  192  where the needle  220  rides. Pulleys  172 ,  174  and  176  are engaged with an actuator arm  202 , which is attached to the pawl  198 . The pawl  198  interfits with two notches  232  located on the face of the needle  220  at about 180 degrees apart which drives the curved needle  220  in a circular arc. The suture head assembly  156  is configured so that the pawl  198  or other needle driver known in the art, does not intrude into or obstruct the area within the curve of the needle  220 . The area within the circular arc of the needle  220  is unobstructed; there is not a hub at the center of the circular arc so that the device  150  can encompass the maximum volume of tissue within the circular arc of the curved needle  220 . In this way, the needle  220  may be rotated through a relatively large arc, allowing the needle  220  to obtain a sufficient “bite” into the tissue. Preferably, the needle  220  will have a radius of curvature of about 3 mm to about 40 mm. In one embodiment, the device  150  sutures within the limit of the diameter of the suture head assembly  156 , which is advantageous to suturing through small cannulas during minimally invasive surgery. In one embodiment, the diameter of the curved needle  220  does not exceed the diameter of the suture head assembly  156 . 
       FIGS. 27A and 27B  show detailed views of the drive mechanism  170  located in the suture head assembly  156  with respect to driving the needle  220  during use of the device  150  (the needle holder assembly  188  and the holder assembly  190  have been removed to show the drive mechanism  170  in detail). The drive mechanism  170  includes the actuator arm  202  that engages pulleys  172 ,  174 , and  176  and the pawl  198  that drives the needle  220  through a curved path. The pawl  198  is located in the distal end of the actuator arm  202  and is capable of engaging the notches  232  located along the face of the needle  220 . A flat spring  200  keeps the pawl  198  engaged into the notches  232  of the needle  220 . When the needle  220  is pushed around to the locations where the anti-rotate spring  136  engages either the trailing end of the needle, or the anti-rotate notch formed into the needle to prevent the needle from backing up, the pawl  198  will ramp out of the drive notch of the needle to the outer surface of the needle and accordingly be pushed back up against the flat spring  200 , permitting the needle  220  to cycle by sliding along the needle until it engages the other drive notch to further advance the needle. The spring force of spring  200  can be chosen to be strong enough to prevent the pawl  198  from backing out of the drive notch of the needle unless the anti-rotate spring  136  has been engaged by the needle. This can permit the needle to move backwards, if desired, during device operation. This can be advantageous to a surgeon as it permits the surgeon to advance the needle up to about 180 degrees of rotation through the tissue without committing to placing the suture, such as 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, or 175 degrees of rotation. For example, if the surgeon feels that the needle hasn&#39;t been placed correctly, the trigger of the suturing device can be released, and the pawl  198  can push against the floor of the notch and against the rearward ramp with sufficient tangential frictional force to withdraw the needle backwards into the needle track. Thus, the needle can start from a starting position wherein the pointed end of the needle is within the needle track, and the needle can be advanced across the full extent of the tissue receiving gap, and if the first drive stroke is not completed such that the anti-rotate spring engages the trailing end of the needle, releasing the actuator will cause the process to reverse, withdrawing the leading end of the needle out of the portion of the needle track, back across the gap, and back into the needle track at the starting position. Similarly, this feature can be used to withdraw the trailing end of the needle back into the tissue receiving gap if the trigger is released during the second drive stroke that would otherwise complete a 360 degree rotation. In another embodiment, the force of spring  200  can be weaker, and the pawl  198  can accordingly be configured to permit the pawl to retract and deflect the spring  200  even if the anti-rotate spring  136  has not been engaged. 
     As the handle  160  is closed and opened, the pawl  198  moves through the same arc as the pulleys. The actuator arm  202  is activated by the user upon squeezing of the handle  160 , and is capable of sweeping back and forth in an arc spanning about 190 degrees or more. 
       FIG. 28  shows a close-up view of the needle holder assembly  188  showing the curved track  192  where the needle  220  resides as well as the needle holder assembly extensions  194  that help keep the latch  210  in place. The suturing needle  220  follows a curved path along the track  192  during rotation of the suturing needle  220 . The curved track  192  for the needle  220  may be machined into the needle assembly  188  and provides a captive curved track  192  so that the needle  220  can be driven around with precision. The curved track  192  includes an inside slot and a larger slot surrounding the inside slot. The larger outside slot provides clearance for the pawl  198 , so that the pawl  198  can maneuver around without hitting anything, and the smaller inside slot provides clearance for a pawl tip  199 , which goes through the smaller inside slot and then into the needle  220  so that the pawl tip  199  can drive the needle  220 . 
       FIG. 29  shows a close-up view of the suture head assembly  156  with the needle holder assembly  188 , the holder assembly  190 , the latch  210  and the needle  220  in view as well as the relationship between the pawl  198  and the actuator arm  202  with respect to the needle  220 . The needle  220  is enclosed within the needle holder assembly  188 , so the sharp pointed end  224  of the needle  220  is not exposed. This needle  220  position, as loaded, is referred to as the “home” position. In the home position, the needle  220  is fully contained within the needle holder assembly  188  to eliminate needle-pricks during handling of the suture head assembly  156 . The needle assembly extensions  194  form a “tongue-in-groove” connection with the latch  210 , which keeps the forces from the needle  220  from opening the thin members of the latch  210 . The needle assembly extensions  194  cause an entrapment at a distal end of the suturing device, thus locking the latch  210  in place. Squeezing the device handle  160  fully operates the device  150  through one full cycle. The first full actuation of the handle  160  drives the needle  220  through about a 190-degree arc. The pointed end  224  of the needle  220  exits the protective enclosure of the needle holder assembly  188 , drives through the tissue to be sutured, and re-enters the protection of the needle holder assembly  188  of the device  150 . This position, after the first squeeze of the handle  160 , is referred to as the “rotation” position. The handle  160  is then released, and the needle  220  remains in the rotation position while the pawl  198  and the actuator arm  220  return to their start position. The handle  160  is then squeezed again driving the needle  220  through about a 190-degree arc returning the needle  220  to the home position. A flat pawl spring  200  keeps the pawl  198  engaged into the pawl notches  232  on the needle  220 . When the needle  220  is pushed around the pawl  198  will be pushed back up against the flat pawl spring  200  and allow the needle  220  to cycle. 
       FIGS. 30 and 31  show top views of the suture head assembly  156 . Needle holder assembly  188  forms a connection with the latch  210 . The latch  210  forms a top cover over the suturing needle  220  which is in the curved track  192  of the needle holder assembly  188 .  FIG. 30  shows the latch  210  in the open position, which is for needle  220  removal and insertion into the needle holder assembly  188 . To insert and/or remove the needle  220  a user may turn the needle  220  180 degrees in its curved track  192  from the as-drawn position. A user may grab the needle  220  by hand or with a surgical tool to either install the needle  220  or remove the needle  220 . By grabbing and lifting the needle  220  out, the needle  220  is removed. By grabbing the needle  220  the needle can be inserted when the latch  210  in the open position.  FIG. 31  shows the latch  210  in the locked position, also known as the forward position. 
       FIG. 32  shows the suturing needle  220 . The two notches  232  are located about 180 degrees apart on the face of the needle  220  and assist in driving the needle  220 . The pawl  198  engages the notches  232  when driving the needle  220  through the circular motion. A third notch  234  is located on the outer surface of the needle  220 . The notch  234  provides an anti-rotation feature by preventing rotation of the needle  220 . The needle  220  is formed as a circular split ring with a gap  222 , a sharp, pointed end  224 , and a blunt end  226 . The needle  220  further comprises an opening  230  to accommodate the leading end of the suturing material or thread  246 . In an embodiment, the opening  230  is the form of an eye though which the leading end of the suturing material or thread  246  may be passed through for attachment to the needle  220 . In the illustrated needle  220 , the needle  220  comprises an opening  230  in the form of a cylindrical bore aligned axially with respect to the needle  220 , located at the blunt end  226 . The opening  230 , can be positioned anywhere along the arc or the needle  220  between the apex  228  and the blunt end  226 . The leading end of the suturing material or thread  246  is inserted into the opening  230  and restrained by mechanically crimping or other connection methods known in the art. To enable the needle  220  to penetrate tissue to a required depth, the arc length of the needle  220  is preferably about 240 degrees to about 300 degrees. The needle  220  comprises two symmetric notches  232  along the face (“drive notches”). The notches  232  are located directly opposite to each other. A similar notch  234  is located on the radially outer edge (“outer notch”) of the needle  220  proximally to the inner notch  232  closer to the sharp, pointed end  224 . The outer notch  234  engages with an anti-rotate spring, whereby rotation of the needle  220  in a direction opposite to the advancing direction or “needle backing-up” is prevented. The positive engagement of the needle outer notch  234  during operation of the suturing device precludes the needle  220  from straying out of sequence during the suturing process. 
       FIG. 33  shows a close-up view of the pawl tip  199  engaging the drive notches  232  of the needle  220 . The drive notches  232  are engaged by the pawl tip  199  of the drive mechanism  170  and enable the needle  220  to undergo a rotary movement upon actuation of the drive mechanism  170 , thereby causing the needle  220  to penetrate into and advance through tissue. 
       FIGS. 34 and 35  show parts of the drive mechanism  170  including return pulleys  172  and  174 . Pulleys  172  and  174  are connected to each other using wires  175 . As can be seen in  FIG. 27A  and  FIG. 27B , pulleys  172  and  174  are made up of four pulleys  178  that are connected together by laser welding or other methods known in the art. The four pulleys  178  produce an over-rotation, of about 190 degrees. The over-rotation leads to the wire  175  design where there is a wire  175  on each set of pulleys  178 . As shown in  FIG. 34  and  FIG. 35 , there are two wires  175  with four pulleys  178 , resulting in the four pulleys  178  being in synch with one another, even under load. The four pulleys  178  are rotationally in sync, i.e., one pulley  178  will follow the other pulley  178 , because the wires  175  are configured to be pulling against one another. The wire  175  may be attached to the pulleys  178  via a hole that the wires  175  are soldered into.  FIG. 35  shows a side view of the suture head assembly  156  which shows the two wires  175  connecting the four pulleys  178  together for synchronized rotation. 
       FIGS. 36 and 37  in conjunction with  FIG. 38 , show the connections and positions of cables  184  and  186  to the drive pulley  176  and to the return pulleys  172  and  174 , respectively, and to the when the handle  160  is in the open position. The cables  184  and  186  may be made from stainless steel. Connected at the proximal end of the suture head assembly  156  there is the spherical portion  158  that contains part of the drive mechanism  170  including two idler pulleys  180  and cables  184  and  186 .  FIG. 36  shows a top view of the suture head assembly  156  with the cable  184  running through two idler pulleys  180  and wrapped around drive pulley  176 .  FIG. 37  shows a top view of the suture head assembly  156  with the cable  186  running through two idler pulleys  180  and wrapped around return pulley  174 . The cable  186  runs from return pulley  174  through the elongated barrel  154  and to the very proximal end of the handle  160 . The force to move the needle  220  from the home position (shown in  FIGS. 36 and 37 ) to a rotation position comes from a return spring  240  that is connected to the cable  184 , resulting in a pre-load (shown in  FIG. 38 ). When the trigger of the handle  160  is squeezed closed, the handle  160  moves to the closed position and the drive pulley  176  turns counterclockwise, driving the needle  220 . At the same time, the cable  186  drives the return pulley  174  counterclockwise and cycles the actuator arm  202  to drive the needle  220  forward through the tissue. The needle  220  is driven through a circular motion, through a cycle, and the cable  184  is compressing the return spring  240  on the other end. When the handle  160  closes more, the actuator arm  202  drives the needle. When the trigger of the handle  160  is released, the front pulley  178 , which is now fully charged with the return spring  240 , will return the needle  220  to the home position. The return spring  240  pulls cable  184 , returning the pulleys to their starting positions, and returning the actuator arm  202  to a position to engage the second drive notch of needle  220 . A second compression-release cycle returns the needle  220  to the home position. Relaxing the trigger of handle  160  takes no power. 
       FIG. 38  shows a side elevational view of the suturing device  150 . The handle  160  includes a number of internal parts—a cable connector  182  has a hole and a shoulder. The shoulder rides against the end of the return spring  240 , and the hole provides an opening for the cable  184 . The return spring  240  is compressed and the cable  184  is soldered or locked to the connector  182 , so that the cable  184  provides a preload onto the return spring  240 . The cable  184  runs from the connector  182  through the return spring  240  over pulley  244 , through the elongated barrel  154 , through the spherical portion  158 , between the idler pulleys  180  and fixed to the drive pulley  176 . The cable  186  is connected at the very proximal end of the handle  160  and lies under pulley  245 , over pulley  242 , through the elongated barrel  154 , through the spherical portion  158 , between the idler pulleys  180  and fixed to the return pulley  174 . 
     When the handle  160  is translated from the open position to the closed position the needle  220  is driven through the tissue. A user has a tactile feel as the needle  220  moves. If the needle  220  runs across something that is impenetrable, the handle  160  will stop moving and the user could feel this in their hand holding the handle. When the handle  160  is in a closed position, the return spring  240  takes on a charge, the return spring  240  has shortened in length. When the handle  160  is released, the return spring  240  pulls the cable  184  and brings the needle  220  back to the home position and also brings the handle  160  back to the open position. The return spring  240  provides a load on the cable  184 . A loop is formed throughout the suturing device  150  that includes the cables  184  and  186  and the pulleys  172 ,  174  and  176  such that cable  184  is attached at one end to the return spring  240 , at the other end to the drive pulley  176 . The cable  186  is attached to the return pulley  174  and then cable  186  attaches to the very proximal end of the handle  160 , thus forming a loop. The return spring  240  can be set to a desired spring-rate so that the return spring  240  performs as desired by the user. The return spring  240  should have a small amount of preload to make sure that the handle  160  opens all the way, which provides that the driving mechanism  170  would return the needle  220  to the home position. 
     The cables  184  and  186  extend through the elongated barrel  154  and connect to the drive mechanism  170  in the suture head assembly  156 . The long length of the cables  184  and  186  provides a small amount of a spring buffer. If the suturing device  150  were to become bound or something locked up at the suture head assembly  156  this would not translate. If the user continued to pull on the handle  160  to close the handle  160 , the cables  184  and  186  would stretch and should not break. The two idler pulleys  180 , which drive the cables  184  and  186  are located in the spherical portion  158 . As shown in  FIG. 34 , the two idler pulleys  180  appear to be one on top of the other, but they are located in a plane with either pulleys  174  and  176  or pulley  178  (see  FIG. 26 ). 
       FIG. 39  shows an alternative embodiment of a suture head assembly  356 . The actuator arm  102  ( FIGS. 3A, 4A and 4B ) of the suture head assembly  56  is replaced by a tendon or band filament  302  ( FIG. 39 ). The cables  84  and  86 , and drive rods  140  and  142  ( FIG. 8 ) can be replaced by an actuator that can move fore and aft with compression and release of the handle  60  ( FIG. 8 ) or  160  ( FIG. 24 ). The actuator can be a drive rod (not shown), and can be constructed of a tensile material that permits lateral elastic flexibility but minimal longitudinal compressibility, such as steel or other metal alloys with spring-like qualities, shape memory alloys, such as NITINOL® or a flexible hardened polymer or plastic such as high density polyethylene or polypropylene. The drive rod can be encased within a passageway inside the elongated barrel  54 , the walls of which can include a sufficiently lubricious material to minimize the friction of the fore and aft movement of the drive rod. For example, the passageway may be made from or include a coating of a fluoropolymer or other lubricious material, such as silicone oil and the like. The drive rod can be connected on its distal end to the tendon or filament  302  by any suitable means (including, for example, the use of a screw, a bolt, adhesive, a weld joint, a hinge joint, or a snap-lock connection). 
     The suture head assembly  356  can be attached rigidly to the elongated barrel  54 . Alternatively, the suture head assembly  356  can be attached moveably to the elongated barrel  54  by an articulating joint as shown in  FIG. 2A  and  FIGS. 20-23 . For example, the proximal end of the suture head assembly  356  ( FIG. 39 ) can be modified to form a partially spherical portion similar to spherical portion  58  ( FIG. 2A ), which can permit superior-inferior motion of the suture head assembly  356  with respect to the elongated barrel  54 . An articulation rod  68  can be used as shown in  FIGS. 20-23  to push and pull the suture head assembly  356  through an arc within the limits of the articulation. Those skilled in the art will recognize there are many possible means of connecting an embodiment exemplified by the suture head assembly  356  to a handle and actuating mechanism to achieve the push-pull motion of the tendon or filament  302 . 
     As shown in  FIG. 39A , in this embodiment the suture head assembly  356  is comprised of two mating components  356 A and  356 B. A needle track  332  is located in the needle track component  356 B. A drive track (not shown) is located in the drive track component  356 A next to the needle track  332 . In this embodiment, the suturing needle  220  exits the suture head assembly  356  from the distal end of aperture  318 , and re-enters the device at the proximal end of aperture  318 . Therefore, in its ‘home’ position, the blunt end  226  of needle  220 , and its attached suture material  246  are situated more proximally in the suture head assembly  356  than the pointed end  224  (not shown). 
     By way of further example, as depicted in  FIG. 39B , device  300  equipped with a suture head assembly  356  may be provided with a flexible proximal segment  354  and include a steering mechanism for controlling curvature of the shaft. The steering mechanism may achieve steering in any suitable manner, such as steering wires. For example, two, four or any other suitable number of steering wires  371  may be used to control movement of device  300 . Steering may be controlled accordingly by way of a steering control mechanism  372 , which may be made in any way known in the art. Similar to the embodiments of  FIGS. 1-38 , an actuator  373  is also provided for activating the suturing head. As will be appreciated by those of skill in the art, the embodiments of  FIGS. 1-38  may similarly be modified to include a flexible barrel ( 54 ,  154 ), as desired. 
     As embodied herein, the tendon  302  may include an elongated flexible member that can slide fore and aft within a track in the suture head assembly  356 . It can have any cross-sectional shape, including for example, round, oval, square, or rectangular. In a preferred embodiment, it is relatively flat, forming a band, which has the advantage of limiting the flexibility of the tendon  302  to one lateral dimension (e.g., superior-inferior and not side-to-side). It is preferably constructed of material that is minimally compressible, allowing for the longitudinal transmission of a pushing as well as a pulling force. In one embodiment, the material from which a tendon is constructed has sufficient tensile properties to exert a spring-like force that opposes lateral flexion. Examples of material with such properties can include, for example, shape memory alloys such as NITINOL®, steel or other metal alloys with spring-like qualities, or a flexible hardened polymer or plastic such as high density polyethylene or polypropylene. In other embodiments, spring-like properties on lateral flexion are not required, where, for example, the lateral movement of the tendon is urged by a spring located with the suture head assembly  356  that exerts a force against the external surface of the tendon. 
     As shown in  FIG. 40 , the tendon  302  is situated in a drive track  333  within the drive track component  356 A of the suture head assembly  356 . The drive track  333  is substantially straight until it reaches the distal portion of the suture head assembly  356 , which at this point is shaped to define an aperture  318 . At this location the drive track  333  in one embodiment divides into an engagement track  334 , and disengagement track  335 , which each follow a curved path conforming to the contour of the suturing needle  220 . As shown in  FIG. 41 , tendon  302  flexes to conform to the shape of the engagement and disengagement tracks  334  and  335 .  FIG. 41  shows a perspective view of the distal flexed end of tendon  302 , to which is attached a cylindrical pawl  308 . The pawl  308  consists of a pawl body  308 A and a pawl tip  308 B. The cylindrical shape of the pawl body  308 A and pawl tip  308 B reduce the frictional resistance to movement of the tip of tendon  302  within engagement and disengagement tracks  334  and  335 . Other cross-sectional shapes of the pawl assembly  308 A and  308 B are also possible, including, for example, an oval, a square a rectangle, or other more complex shapes. Moreover, the pawl body can also be constructed as a roller bearing, further reducing frictional resistance to the fore and aft motion of the tendon  302 .  FIG. 42A  shows how the pawl tip  308 B engages a trailing notch  232 B or leading notch  232 A on needle  220  to allow the tendon  302  to advance the needle  220  within its track  332 .  FIG. 42B  shows the needle  220  in isolation, in which the drive notches  232 A and  232 B are located on the side of the needle  220 , and the anti-rotate notch  234  is located on the outer circumference of the needle  220 . A pointed end  224  pierces the target tissue during forward rotation of the needle  220 , and suture material  246  is attached to the blunt end  226  of needle  220 . 
     In one embodiment, notches  232 A and  232 B have a substantially perpendicular leading wall  232 A 1  and  232 B 1  against which the pawl tip  308 B can engage and move the needle forward in its track  332 ; whereas the angled trailing walls  232 A 2  and  232 B 2  allow the pawl tip  308 B to slide smoothly into position in the notches  232  and  233  as it advances within the engagement track  334 . The leading walls  232 A 1  and  232 B 1  of notches  232 A and  232 B can also be inclined away from the pointed end of the needle, the angle of inclination being in the range of about 91 degrees to about 160 degrees with respect to the surface of the needle. The trailing walls  232 A 2  and  23 B 2  of notches  232 A and  232 B can also be inclined away from the pointed end of the needle, the angle of inclination being in the range of about 91 degrees to about 160 degrees with respect to the surface of the needle. 
     Alternatively, the trailing wall  232 B 2  of trailing notch  232 B can also be made substantially perpendicular to the surface of the needle, with a gap between the leading wall  232 B 1  and the trailing wall  232 B 2  large enough to accommodate the pawl tip  308 B. This embodiment allows the user either to advance the needle  220  by pushing the tendon  302  distally, or move the needle backwards by pulling the tendon  302  proximally when the pawl tip  308 B is engaged in the trailing notch  232 B. The surgeon can thus ‘back out’ the needle from the tissue being sutured when an obstacle is encountered that prevents complete penetration of the needle  220 , or when repositioning of the needle in tissue is desired for other reasons. Under these circumstances, the leading wall  233 A 1  of leading notch  232 A is preferably not angled away from the pointed end in order to avoid a ‘barb-like’ structure that would impede reversal of the needle path in tissue. In addition, the leading wall  233 A 1  can have a chamfered or rounded corner at the junction with the surface of needle  220  to facilitate backing the needle out of tissue. For the same reasons, the anti-rotate notch  234  can have a leading wall that does not angle away from the pointed end  224  of the needle  220 , and it can have a chamfered or rounded corner at the junction with the surface of the needle  220 . The trailing wall  232 B 2  of trailing notch  232 B can also be constructed with a chamfered or rounded corner to facilitate forward movement of the needle through tissue. 
     As shown in  FIG. 43 , in one embodiment, the track  333  divides into engagement track  334  and disengagement track  335 . Engagement track  334  is adjacent to and side-by-side with the needle track  332 . Disengagement track  335  is adjacent to the outside circumference of engagement track  334 . Pawl body guides  336 A ( FIG. 43 ) and  336 B ( FIG. 44 ) separate engagement track  334  from disengagement track  335 , except for a gap between the pawl body guides  336 A and  336 B running the length of the tracks  334  and  335 . (best shown in  FIG. 46A ) The base of pawl body guide  336 A is either formed or attached along the inside wall of the drive track side  356 A of suture head assembly  356 . The base of pawl body guide  336 B is either formed or attached along the inside wall of the needle track side  356 B of suture head assembly  356 . The pawl body guides  336 A and  336 B terminate short of the ends of the tracks  334  and  335 , both at their proximal and distal ends, at proximal chamber  380  and distal chamber  390 . This allows engagement track  334  to be in full communication with disengagement track  335  at both the proximal chamber  380  and the distal chamber  390  of the tracks. Tendon  302  moves only within engagement track  334 , whereas the distal end  302 A of tendon  302  and pawl  308  can move in engagement track  334  when driving needle  220 , and move in disengagement track  305  when returning to proximal chamber  380 . At the proximal end  308  of the engagement and disengagement tracks  334  and  335  (i.e. at the proximal chamber  380 ), the spring force caused by tendon  302  being flexed in a downward direction causes the pawl  308  to move up into the proximal end of engagement track  334 . As the tendon moves distally in the engagement track  334 , it engages the trailing notch  232 B or leading notch  232 A of needle  220 , moving the needle  220  forward in its track  332 . When the pawl  308  reaches the distal end of the track  334  at the distal chamber  390 , the tendon  302  is flexed in an upward direction, and the spring force of tendon  302  now exerts a downward force on the pawl  308 . The pawl  308  drops down into the distal end of disengagement track  335 . The distal end of tendon  302  comprises a narrowed segment  302 A, allowing this distal segment to travel within the disengagement track  335  as tendon  302  is pulled proximally, because the narrower dimension of the distal end of tendon  302  clears the pawl body guides  336 A and  336 B. The more proximal portion of tendon  302 , at full width, continues to travel in engagement track  334 , being held in place by the pawl body guides  336 A and  336 B. 
       FIG. 45  shows a top perspective view of the suture head assembly  356 . The drive track side  356 A is mated to the needle track side  356 B. The needle track  332  is formed on the outside surface of the needle track side  356 B of the suture head assembly  356 . In this embodiment, a second opening  357 , located at the distal end of aperture  318 , is where the pointed end  224  of needle  220  exits the device. A first opening  358 , located at the proximal end of aperture  318 , is where the pointed end  224  of needle  220  re-enters the suture head assembly  356  after penetrating the target tissue.  FIG. 46A  shows a cutaway top perspective view of suture head assembly  356 , in which the roof of track  333 , the proximal chamber  380 , and the distal chamber  390  have been cut away. The pawl  308  can be seen in cross-section within the proximal end of engagement track  334 , adjacent to the cross-section of needle  220  at trailing notch  232 B. Pawl tip  308 B is engaged in trailing notch  232 B of needle  220 . The pawl  308  is held within the track by pawl body guides  336  A and  336 B. The narrow segment  302 A of tendon  302  can pass through the gap between pawl body guides  336 A and  336 B. Thus while the main portion of tendon  302  remains within engagement track  334 , the pawl  308  and narrow segment  302 A of tendon  302  can travel either in engagement track  334  or engagement track  335 . A thrust collar  360 , shown in  FIG. 46A  (and in isolation in  FIG. 46B ) snaps over the outside of needle  220  into suture head assembly  356  to hold needle  220  within its needle track  332 . Alternatively, a cartridge  88 , as shown in  FIG. 2A  and  FIG. 2B , can be used, which can then be attached to a cartridge holder assembly  90 . A cartridge  88  can provide operating room personnel with the added safety of avoiding inadvertent puncture from handling an exposed needle  220 . 
     A further enhancement of suture head assembly  356  is shown in  FIG. 47 . An anti-rotate spring  346  (shown in isolation in  FIG. 48 ), anchored inside suture head assembly  356  can engage a notch on the outer circumference of needle  220  to prevent backward migration of needle  220  in its track  332 . As shown in  FIG. 44 , the anti-rotate spring  346  contacts the surface of needle  220  through an aperture  347  lateral to the disengagement track  335  so as not to interfere with movement of the distal end of tendon  302  and pawl  308 . In a preferred embodiment, the anti-rotate notch  234  is located on the outer circumference of needle  220 , and sufficiently distally along the needle to cause engagement of the anti-rotate spring  346  only when the pointed end of needle  220  is within the confines of suture head assembly  356 . 
     An additional feature to coax pawl  308  to engage the notch  232 A or  232 B of needle  220  is shown in  FIG. 47 . A flat spring  348  (shown in isolation in  FIG. 49 ) is situated within proximal chamber  380  of the drive track side  356 A of suture head assembly  356 . The flat spring  348  urges the pawl  308  against the side of needle  220  to engage the pawl tip  308 B with either the trailing notch  232 B or leading notch  232 A. The force exerted by flat spring  348  is substantially weaker than the spring force exerted by the downwardly flexed tendon  302 , allowing the distal end of tendon  302  and the pawl  308  to move into position at the proximal end of engagement track  334 , compressing flat spring  348  if necessary. Thus it is possible for pawl  308  to engage the notch  232 A or  232 B of needle  220  even if the pawl  308  and notch  232 A or  232 B are not exactly adjacent to one another.  FIG. 50A  is a cross-sectional view of suture head assembly  356  showing pawl  308  positioned immediately proximal to trailing notch  232 B of needle  220 .  FIG. 50B  is a view of  FIG. 50A  through section B-B. Pawl tip  308 B is pressed against the side of needle  220  immediately proximal to notch  232 B by compressed flat spring  348 .  FIG. 50C  is a view of  FIG. 50A  through section C-C. Flat spring  348  deflected by pawl  308 , maintaining pressure of pawl tip  308 B against the side of needle  220 .  FIG. 51A  is a cross-sectional view of suture head assembly  356  showing pawl  308  positioned within trailing notch  232 B of needle  220 .  FIG. 51B  is a view of  FIG. 51A  through section B-B. At this point, pawl tip  308 B is engaged with notch  232 B of needle  220 , spring  348  is in a relaxed position, and pawl  308  is aligned with the side wall of engagement track  334 , allowing it to proceed distally to drive the needle  220  within its needle track  332 .  FIG. 51C  is a view of  FIG. 51A  through section C-C. Flat spring  348  is now in a relaxed position, and pawl tip  308 B is situated within notch  232 B of needle  220 . Once the pawl  308  moves distally within engagement track  334 , the confines of the track wall itself keep the pawl tip  308 B engaged with notches  232 B or  232 A. 
       FIGS. 52-59  are sectional views through the length of suture head assembly  356  showing the progression of a complete four stroke movement (two push-pull cycles) that causes needle  220  to undergo a 360 degree rotation within its track  332 , penetrating the target tissue in the first stroke of the first cycle. In  FIG. 52 , the pawl  308  is situated at the proximal end of engagement track  334 , and is engaged with notch  232 B of needle  220 . Anti-rotate spring  346  is engaged with the anti-rotate notch  234  on the outer circumference of needle  220 , preventing it from moving in a reverse direction. In  FIG. 53 , the tendon  302  has been pushed distally in a first stroke, and has driven pawl  308  to the distal end of engagement track  334 . When the ends of pawl guides  336 A and  336 B have been cleared, the distal end of tendon  302  and pawl  308  snap by spring force into the distal end of disengagement track  335 . In this embodiment, movement of needle  220  by pawl  308  in this stroke has caused the pointed end of needle  220  to exit the second opening  357  of suture head assembly  356 , traverse the aperture  318 , penetrated the target tissue, and re-entered the first opening  358  of suture head assembly  356 . In  FIG. 54 , the pawl  308  and the distal end of tendon  302  have dropped into the distal end of the disengagement track  335  by spring force of the upwardly deflected tendon  302 . The pull stroke in the first suturing cycle is shown in  FIG. 55 . The pawl  308  is being pulled by tendon  302 , which is being retracted proximally by the surgeon via the handle  60  or  160 . Backward migration of the needle  220  is prevented by the engagement of anti-rotate spring  346  against the hub or blunt end  226  of needle  220 . This helps to keep the leading notch  232 A of needle  220  aligned with the proximal chamber  380 , where the pawl  308  can engage it. In  FIG. 56 , the pawl  308  has reached the end of the pull stroke at the proximal end of disengagement track  335 . At this point the tendon  302  is significantly deflected downward, generating a spring force to drive pawl  308  upward into the proximal end of engagement track  334 , after it has cleared the pawl body guide  336 A and  336 B. In  FIG. 57 , the pawl  308  has been driven by spring force into engagement with the leading notch  232 A of needle  220 . The push stroke of the second suturing cycle involves pushing the tendon  302  distally, driving the pawl  308  and pointed end  224  of needle  220  toward the distal end of needle track  332  (visually indistinguishable from engagement track  334  in this view). This is shown in  FIG. 58 , where the pointed end  224  of needle  220  has advanced half-way through needle track  332 . In  FIG. 59 , the push stroke of the second suturing cycle has been completed, with the pawl having dropped into the distal end of disengagement track  335  by spring force from the upward deflection of tendon  302 . The needle  220  has returned to its home position. Backward movement of the needle  220  is prevented by anti-rotate spring  346  engagement with the anti-rotate notch  234  of needle  220 . The trailing notch  232 B of needle  220  is in position to be engaged by pawl  308  at the proximal end of engagement track  334 . As shown in  FIG. 60 , the pull stroke of the second suturing cycle is a retraction of tendon  302  proximally, pulling the pawl  308  proximally within disengagement track  335  and bringing it into position in the proximal chamber  380  to re-engage the trailing notch  232 B of needle  220 . Backward migration of needle  220  is prevented by anti-rotation spring  346  engaging the anti-rotation notch  234  of needle  220 . The suturing cycle is ready to resume if desired at this point. 
     Those skilled in the art will recognize that the movement of the distal end  302 B of tendon  302  and pawl  308  into and out of notches  232 A and  232 B can be effected by springs situated within the suture head assembly  356  at the beginning of disengagement track  335  and at the end of engagement track  334 . Externally applied spring force, or even the placement of ramps in the engagement and disengagement tracks can cause the pawl  308  to be re-directed into the proximal end of engagement track  334 , and into the distal end of disengagement track  335 . 
     It will also be apparent to those skilled in the art that the direction of travel of needle  220  can be reversed by having the home position for the trailing notch situated in the distal end of needle track  332 . In this case, the pawl and tendon are situated at the distal end of engagement track  334  at the start of the first stroke of the first suturing cycle. The first (pull) stroke of the cycle would cause the pointed end of needle  220  to exit the first opening  358 , pass through the target tissue, and re-enter the suture head assembly at the second opening  357 . Structured in this way, the disengagement track  335  would be equipped with a spring or ramp to press the pawl  308  into the notch  232 A or  232 B at the distal end of the track, and with a spring or ramp to disengage the pawl  308  from the notch  232 A or  232 B at the proximal end of the track. Alternatively, the disengagement track  335  can be constructed so that it lies within the inner circumference of the engagement track  334  and needle track  332 . Under this circumstance, the spring-like property of tendon  302  will naturally drive the pawl  308  into notch  232 A or  232 B at the distal end, and out of notch  232 A and  232 B at the proximal end. 
     In an embodiment, the entire suturing device  150  can be designed as a single unit which may be either reusable or disposed after a single use. In one embodiment, the entire suturing device  150  can be designed from a number of separable parts where each unit may be either reusable or disposed after a single use. 
     The suturing device  150  is configured to provide a “pistol like” grip for the user that includes an elongated barrel  154  and a handle  160  that extends from the proximal end of the elongated barrel  154 . The elongated barrel  154  has either a linear or non-linear configuration, including but not limited to, straight, curved and angled configurations. A suture head assembly  156  is removably attached to the distal end of the elongated barrel  154 . The suture head assembly  156  contains a portion of the drive mechanism  170  of the device  150 . The working end of the suture head assembly  156  has a needle holder assembly  188  to which a suturing needle  220  may reside. A latch  210  forms a cover over the needle  220 . 
     An arcuate suturing needle  220  having a sharp, pointed end  224  is slidably mounted in a circular track  192  of the needle holder assembly  188 . The blunt end of the needle  226  is connected to the suturing material or thread  246 . The needle  220  normally resides in a “home” position in the track  192  such that the gap in the arcuate suturing needle  222  is in alignment with an aperture  218  in the needle holder assembly  188 . The sharp, pointed end of the needle  224  is situated on one side and entirely within the confines of the needle holder aperture  218 ; the pointed end of the needle  224  is, therefore, shielded by the needle holder assembly  188 . The blunt end of the suturing needle  226  that is attached to the suturing material or thread  246  is located at the opposite side of the aperture  218 . The sharp, pointed end of the needle  224  is, therefore, wholly contained within the needle holder assembly  188  and does not protrude beyond the housing of the needle holder assembly  188 . Thus, the sharp pointed end of the needle  224  is not exposed to the user. 
     In accordance with the presently disclosed embodiments, the needle  220  may be releasably engaged by the needle driver  198  that is rotatably mounted within the suture head assembly  156  so that the needle  220  can be rotated from the home position by about 360 degrees about the central vertical axis of the needle holder assembly  188 . Such a rotary action of the needle  220  causes the sharp point  224  to advance across the needle holder assembly  188  so as to span the aperture  218 . Thus, when the device  150  is positioned such that the incised tissue segments to be sutured are situated at the needle holder assembly aperture  218 , the needle  220  penetrates the tissue segments and spans the incision between them. A continued rotary movement of the needle  220  causes the needle  220  to return to the home position, and thereby causes the suturing material or thread  246  attached to the needle  220  to be pulled into and through the tissue in an inward direction on one side of the tissue incision, and upwards and out through the tissue on the opposite side of the incision. Thus, the suture material or thread  246  follows the curved path of the needle  220  to bind the tissues together with a stitch of material or thread  246  across the incision in a manner similar to manual suturing, wherein the needle  220  is “pushed” from the blunt end  226  and then “pulled” from the pointed end  224  by the pawl  198 . Preferably, an anchoring mechanism is provided at the trailing terminal end of the suturing material or thread  246  to prevent the material  246  from being pulled completely through and out of the tissue segments. For example, the anchoring mechanism can be a pre-tied or a welded loop, a knot wherein the suture material or thread  246  is simply tied, or a double-stranded, looped suture is that attached to the suturing needle  220 . The rotary movement of the needle  220  within the needle holder assembly  188  is accomplished by a pawl  198  that may be operated by the user by holding the suturing device  150  with one hand in a pistol-like grip around the handle  160 , and using at least one finger of that hand to activate. 
     In accordance with further aspects of the invention, for purposes of illustration and not limitation,  FIGS. 61-71  depict a further embodiment of a suturing head  500  for a suturing instrument. 
       FIGS. 61-62  illustrate perspective views of this embodiment, both in plain view and showing hidden features, respectively. As illustrated, suturing head  500  is comprised of two main housing components,  502  and  504 . Housing component  502  defines a portion of a needle track  506  that is complete when components  502 ,  504  are assembled. This embodiment is similar to that of  FIG. 39 , but with certain differences. Significantly, in contrast to the embodiment of  FIG. 39 , this embodiment operates by moving needle  520  through needle track  506  during a pull stroke of filament  530 , rather than during a push stroke. Distal end  534  of filament  530  is attached to an engagement mechanism  550  that selectively engages notches formed in the needle  520  in a manner similar to other embodiments described herein. As depicted in  FIG. 63 , engagement mechanism rides in an arcuate track  505  formed in housing component  504  that is generally concentric with the needle track  506 . Suturing head  500  includes a tissue capture gap  540 , similar to the embodiment of  FIG. 39 . 
       FIG. 65  depicts the engagement mechanism that rides in track  505 . As depicted, engagement mechanism  550  includes four main components: cap  552 , sleeve  554 , piston  556  and a chamber  558  housing a compression spring  559  (spring  559  is depicted in  FIG. 67(B) ). In operation, sleeve  554  is affixed to distal end  534  of filament  530 , piston  556  is received within sleeve  554 . Next spring  559  is inserted into cap  552 , which in turn is attached to sleeve  554 . Reduced diameter portion  556   a  of piston  556  is urged through bore  554   a  of sleeve  554 . Portion  556   a  of piston  556  mates with notches  526 ,  528  in needle  520 . The operation of suturing head  500  through a complete cycle will now be described. 
     As depicted in  FIG. 66 , needle  520  having a first pointed end  522  and a second end  524  is in the home position prior to a rotation cycle, and engagement mechanism  550  is engaged with notch  528  in needle  520 . As depicted, needle includes a hollow  529  in second end  524  of needle  520  for receiving a suture (not shown). Filament  530  further includes an enlarged portion  535  for riding against needle track  506  to reduce friction and ease operation of the suturing head. As further depicted, tip  562  of pawl  560  is biased to engage with antirotate notch  527  formed into the outer circumferential surface of needle  527 . 
     As depicted in  FIG. 67(A) , filament  530  is pulled proximally through the suturing instrument, causing engagement mechanism  550  to urge against notch  528  in needle, resulting in needle  520  being drawn through track  506 , across gap  540 , and back into track  506 . Tip  562  of pawl  560  slides out of antirotate notch  527  of needle  520  and drags along the needle  520  as needle  520  moves through needle track  506 . As can be seen in side cross-sectional view  FIG. 67(B) , end  556   a  of piston  556  is urged against notch  528  of needle  520  by spring  559 .  FIG. 68  depicts needle  520  after having been moved through a 180 degree rotation. As can be seen in  FIG. 68 , second end  524  of needle has moved past tip  562  of pawl  560 , and tip  562  of pawl snaps into the needle track  506  to prevent the needle  520  from reversing direction. At this point, filament  530  is once again advanced distally, causing tip  556   a  of piston  556  to urge against the distal inclined surface  528   a  of notch  528 . Inclined surface  528   a  acts as a ramp to push piston  556  into chamber  558  against the force of spring  559  until surface  556   a  rides up out of notch  528 , and over the outer surface of needle  520  through track  505  until it passes over needle  520  and pops back out. As engagement mechanism  550  continues to be guided by arcuate notch  505 , it encounters first end  522  of needle  520 . The pointed end  522  of needle  520  once again acts as a ramp, compressing spring  559  as surface  556   a  rides up and over the needle  520  until surface  556   a  reaches notch  526 . Upon reaching the notch  526 , the piston snaps down into the notch. At this position, engagement mechanism is as depicted in  FIG. 69 . 
     Next, filament  530  is once again pulled proximally through device causing the needle  520  to move through another 180 degree rotation, returning the needle  520  to the home position as depicted in  FIGS. 70(A)-70(B) . While antirotate notch  527  can move past tip  562  of pawl  560 , when filament  530  is moved distally once again to pick up the needle at notch  528 , needle  520  will move backward slightly until notch  527  engages with pawl tip  562 . At that point, surface  556   a  of engagement mechanism  550  rides up inclined surface  526   a  and travels over the outer lateral surface of the needle  520  until the piston snaps into notch  528 , preparing the suturing head  500  for another cycle as depicted in  FIGS. 71(A)-71(B) . 
     Suturing head  520  can be constructed using any desired techniques and any desired materials as described herein, for example, with reference to suturing head  356 . Preferably, suturing head  500  is made from a polymeric material to permit manufacture of a low-cost, disposable device. Suturing head  500  can be mounted on a flexible shaft as depicted in  FIG. 39(B) . 
     In accordance with still further aspects of the invention, for purposes of further illustration and not limitation,  FIGS. 72-85  depict further variations of the device generally depicted at  FIGS. 1-38 . 
     As depicted in  FIG. 72 , device  600  is provided with a handle  660  that has been found to be particularly user-friendly and comfortable. Device  600  also includes a suturing head  610 , an elongate tubular body  640 , and a roticulation region  650 . 
     The roticulation region  650  is illustrated in  FIG. 73 . Roticulation section includes a hub  652  that is attached to tubular body  640 . Hub  652  is rotatably mounted on a cylindrical bearing surface  658 , having a plurality of elongate detents  659  surrounding the bearing surface  658 . A detent ball  654  is contained within a detent housing  655 , wherein a spring  656  urges detent ball  656  into a detent  659 , preventing the hub from rotating freely, but also permitting hub to be rotated (“roticulated”) about the axis of device  600 , thereby permitting roticulation of the suturing head  610 . 
     As with the suturing head depicted, for example, in  FIGS. 30-31 , a latch  612  is also provided in the embodiment of  FIG. 72  to cover the suturing needle. Specifically, as depicted in  FIGS. 74-76 , latch  612  is provided, and is preferably biased (e.g., by a spring) to the closed position. While latch  612  can be retracted proximally by pushing on the latch  612  itself, during a procedure latch  612  may not be easily accessible. Thus, if the device  600  should jam, to avoid the difficulty in moving the latch backward to permit the needle to fall out of device, a pull wire  616  is provided that is attached at its distal end to the latch  612  (inside of a bore  614 ), and at its proximal end to a release trigger  618  that pivots about a point  618   a . Thus, if it is desired to retract the latch  612  to permit the needle to fall out in the event of a jam, it can be released, the device  600  can be withdrawn, and the needle can be removed with forceps. The device  600  can then be reused with a new needle. 
       FIGS. 77-83  depict an alternative drive mechanism for the suturing head  610 . Specifically, all components of the drive mechanism are fitted to one side of the suturing head  610   a , rather than being anchored to both sides of the suturing head  610 . This is very advantageous in assembly. Specifically, all drive components (pulleys and the like) are attached to side  610   a  of the suturing head. This prevents any inconvenience in needing to align the pulleys and other drive components with two opposing housing sections, and facilitates assembly generally as this design permits the drive components to be stacked and attached to a single member. As will be noted, the drive components bear some similarity to those depicted in  FIGS. 34-35 . A drive cable  634  is routed around a drive idler  624 , and into the drive pulley  620   a . Drive pulley  620   a , in turn, drives an idler pulley  621  by way of an actuator arm  628  when advancing the suturing needle. A link or strut  622  is provided that acts as a stop for rotation of pulley  621  by engaging a bearing surface  621   b  in groove  621   a . A needle engagement mechanism/needle assembly extension  628   a  is provided for driving the suturing needle (not depicted). In addition, a return cable  636  is routed around a return idler  626 , and into the return pulley  620   b , which is concentric with the drive pulley  620   a . Return pulley  620   b , in turn, drives idler pulley  621  by way of actuator arm  628  in a direction opposite from the drive pulley  620   a , causing engagement mechanism  628  a to return to the home position to repeat the half cycle.  FIGS. 84-85  depict cross sectional and three dimensional wireframe views of the handle portion  660  of device  600 , respectively, depicting, for example, actuator handle  662  as well as the arrangement of interior passages through which drive and return cables are routed. The return cable  636  is preferably spring-loaded so as to cause the needle engagement mechanism  628   a  to return to its home position. 
     The suturing devices of the presently disclosed embodiments can be used for laparoscopic procedures, including but not limited to laparoscopic colostomy, colectomy, adrenalectomy, splenectomy, repair of paraesophageal hernia, inguinal hernia repair, ventral hernia repair, Nissen fundoplication, liver lobectomy, gastrectomy, small bowel resection, treatment of small bowel obstruction, distal pancreatectomy, nephrectomy and gastric bypass. Those skilled in the art will recognize that the presently disclosed embodiments can be used in other laparoscopic procedures. 
     In using the device  150  of the presently disclosed embodiments, the abdomen is insufflated with gas to create a working space for the user. Any gas known to those skilled in the art including, but not limited to, nitrogen or carbon dioxide, can be used. Access portals are established using trocars in locations to suit the particular surgical procedure. A variety of surgical instruments may then be inserted into the body through these access ports/cannulas. The user then introduces the distal end portion of suturing device  150  into a cannula, and then laterally articulates the suture head assembly  156  using the articulation lever  166  located just distal to the top of the handle  160 . The suture head assembly  156  is then positioned relative to the tissue/vessel to be sutured together, and the user locks the suture head assembly  156  in place using the locking lever  164 . The user then, through manipulation of the suturing device  150 , positions a plurality of separated tissue segments into the opening defined at the distal end portion of the suture head assembly  156  and within the aperture  218  of the needle holder assembly  188 . The user, using only one hand, may manipulate the device  150  while actuating the handle  160  to close an incision with a continuous suture whose stitches may be individually tensioned precisely and uniformly along the length of the suture similar to suturing done by hand in the conventional way. The user may employ a single suture which would extend the entire length of the incision or multiple sutures. Thus, by placement of the device  150  with the needle holder assembly aperture  218  spanning the incised tissue segments and actuating the handle  160 , the suturing device  150  enables the user to lay down a running stitch or interrupted stitch to close the tissue incision in a time efficient manner. Those skilled in the art will recognize that any conventional procedure for conducting laparoscopic surgery can be used with the device  150 . 
     The minimalized structural design of the suture head assembly  156  enables the user to have a clear, unobstructed view of the suturing needle  220  during advancement through the tissue segments during the course of a suturing operation, thereby enabling precise placement of the suturing device  150  to provide uniform sutures and precluding the risk of tearing tissue by placement too close to the edge of the incision. The suturing device  150  is then advanced a short distance along the incision and the aforementioned operation is repeated to produce another stitch comprising the suturing material or thread  246 . 
     The user may continue to manipulate the suturing device  150 , alternately advancing and actuating rotation of the needle  220  about an axis that is generally parallel to the direction of advancement to create a continuous suture which may extend through the entire length of the incision or a series of interrupted stitches. After each individual stitch is laid down, the stitch is tightened by exerting a pull on the suturing material or thread  246  so that the resultant suture is tensioned uniformly along the length of the incised tissue segments. Therefore, a tight closure of the segments is accomplished and bleeding and tearing of tissue are minimized. Once the appropriate amount of suture material or thread  246  has been placed, the user can use a needle grasper to tighten and knot the formed stitches. 
     The suturing device  150  may be configured in different ways with respect to length and angle of the suture head assembly  156 . The size of the needle  220 , the needle holder assembly  188 , the needle holder aperture  218  and the aperture position may also be varied for use in open surgery to perform procedures such as closing of the fascia, skin closure, soft tissue attachment, anastomosis, fixation of mesh, grafts and other artificial materials. Moreover, devices made in accordance with the teachings herein can be used in combination with needle loader devices described, for example, in U.S. patent application Ser. No. 12/175,442, filed Jul. 17, 2008. 
     All patents, patent applications, and published references cited herein are hereby incorporated by reference in their entirety. It will be appreciated that one or more of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the present disclosure.