Abstract:
A surgical access device comprising a tissue separating obturator suitable for connection with a cannula is disclosed. The obturator includes an elongate shaft having a transparent distal tip. The elongate shaft extends along a longitudinal axis and defines a lumen. The transparent distal tip has a tapered configuration and includes an inner surface and an outer surface adapted for penetrating tissue. The lumen is sized and configured to receive an optical instrument such as a laparoscope. The surgical access device further includes a scope lock at the proximal end of the shaft portion. The lock includes a multi-fingered collet coaxial with the lumen. The inner diameter of the collet is smaller than an outer diameter of the optical instrument and the fingers of the collet provide frictional engagement with the outer diameter of the optical instrument that is inserted into the lumen of the obturator.

Description:
This application is a continuation of co-pending U.S. patent application Ser. No. 13/085,194 entitled “Bladeless optical obturator” filed on Apr. 12, 2011 which is a continuation of U.S. patent application Ser. No. 10/956,167 entitled “Bladeless optical obturator” filed on Oct. 1, 2004 now U.S. Pat. No. 7,947,058 which is continuation-in-part of U.S. application Ser. No. 10/489,403, filed on Mar. 11, 2004, now U.S. Pat. No. 7,686,823, which is a 371 of International Application No. PCT/US02/06759, filed on Mar. 4, 2002 based on Provisional Application Ser. No. 60/324,613, filed on Sep. 24, 2001, and entitled “Bladeless obturator,” all of which are fully incorporated herein by reference in their entireties. U.S. patent application Ser. No. 10/956,167 entitled “Bladeless optical obturator” filed on Oct. 1, 2004 further claims priority to provisional application Ser. No. 60/508,390, filed on Oct. 3, 2003, entitled “Bladeless optical obturator,” which is fully incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to trocar systems including obturators and, more specifically, to blunt tip obturators having hollow shafts for insertion of optical instruments. 
     2. Discussion of the Prior Art 
     Trocar systems have been of particular advantage in facilitating less invasive surgery across a body wall and within a body cavity. This is particularly true in abdominal surgery where trocars have provided a working channel across the abdominal wall to facilitate the use of instruments within the abdominal cavity. 
     The trocar systems of the past typically included a cannula, which provides the working channel, and an obturator which is used to place the cannula across the abdominal wall. The obturator is inserted into the working channel of the cannula and then pushed through the abdominal wall with a penetration force of sufficient magnitude resulting in penetration of the abdominal wall. Once the cannula is in place, the obturator can be removed. 
     Obturators have been developed with an attempt to reduce the penetration force of the abdominal wall. For example, sharp blades, sharp edges and piercing points have typically been used to enable the obturator to cut or pierce its way through the abdominal wall. While the sharp blades, sharp edges and piercing points have facilitated a reduced penetration force, they have also caused larger trocar site defects. These trocar site defects may have to be sutured closed resulting in increased operating room costs and procedural time. Moreover, once the abdominal wall has been penetrated, the sharp blades, sharp edges and piercing points of the obturator may still cause damage to the vessels and organs that lie within the peritoneal cavity. For example, the blades on the obturators that serve to cut tissue during insertion may also cut vessels or puncture organs that may result in patient injury or surgical complications. 
     In some cases, shields have been provided with the obturators in order to sense penetration of the abdominal wall and immediately shield the sharp blades, edges or piercing points. These shielding systems are typically complex and require some time to deploy and, as such, many have not been effective in protecting the vessels and organs against the sharp blades, edges or piercing points. Accordingly, there remains a need in the art for an improved bladeless obturator that separates tissue during insertion through a body wall. Moreover, there is a need for a transparent blunt tip obturator having a hollow shaft to enable insertion of an optical instrument to view the insertion of the obturator through the body wall. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a bladeless trocar obturator to separate or divaricate body tissue during insertion through a body wall. The distal tip of the bladeless obturator is constructed of a transparent material to enable visualization of tissue during the insertion of the obturator through the body wall. The bladeless obturator is configured to enable the insertion of a conventional laparoscope which typically includes an imaging element and fiber optic light fibers. During use, the bladeless obturator is first inserted into and through a trocar seal and cannula. A conventional laparoscope is then inserted into the proximal end of the bladeless obturator and advanced to the distal tip of the obturator. An endoscopic video camera is attached to the proximal end of the laparoscope and the bladeless trocar system is then axially advanced by the surgeon through the body wall, the surgeon can visually observe the tissue as it is being separated via a video monitor that is connected to the endoscopic video camera. 
     In one aspect, the obturator of the invention comprises a shaft extending along an axis between a proximal end and a distal end; and a bladeless tip disposed at the distal end of the shaft and having a generally tapered configuration with an outer surface, the outer surface extending distally to a blunt point with a pair of side sections having a common shape and being separated by at least one intermediate section, wherein each of the side sections extends from the blunt point radially outwardly with progressive positions proximally along the axis, and the shaft is sized and configured to receive an optical instrument having a distal end to receive an image of the body tissue. With this aspect, the tapered configuration facilitates separation or spreading of different layers of the body tissue and provides proper alignment of the tip between the layers. The side sections include a distal portion and a proximal portion, the distal portion of the side sections being twisted radially with respect to the proximal portion of the side sections. The intermediate section includes a distal portion and a proximal portion, the distal portion of the intermediate section being twisted in a first radial direction and the proximal portion of the intermediate section being twisted in a second radial direction opposite the first radial direction. 
     The bladeless tip can be formed from a transparent material or a translucent material. The bladeless tip can be formed from a plastic material or a glass material. The plastic material can be at least one of polycarbonate, polyphenylsulfone, polyetherimide, acrylic, and polyvinyl chloride. The bladeless obturator can be constructed such that at least one of the shaft and the tip is formed from a reusable or a disposable material. The reusable material can be a metallic material or an autoclavable polymer. The bladeless tip can be generally hollow or substantially solid to receive the distal end of the optical instrument. The bladeless tip can also be solid. The bladeless tip can further comprise at least one portion that is marked differently from the rest of the tip to serve as an indicator, for example, of depth as the tip is being inserted into the body tissue. The bladeless tip can be shaped and configured to receive the distal end of the optical instrument having an angled or non-angled lens. The bladeless tip can further comprise a ledge to provide proper positioning of the distal end of the optical instrument having an angled or non-angled lens. The bladeless tip can further comprise a bulbous section to accommodate the distal end of the angled lens optical instrument. The bladeless tip can be further coated or formed from a soft elastomeric material. The shaft and the tip can be connected together by adhesive bonding, ultrasonic welding, snap-fitting, with a shrink tube, or by overmolding the tip over the shaft. The bladeless tip can further comprise a cutout section to provide the distal end of the optical instrument with direct vision of the body tissue. 
     In another aspect of the invention, the bladeless obturator further comprises a lock disposed at the proximal end of the shaft to frictionally lock the optical instrument in an axial position in the shaft. The lock operates to prevent the optical instrument from moving axially relative to the shaft while allowing the optical instrument to rotate freely about the shaft. The lock can be constructed from a plastic material including polycarbonate. The lock can be a multi-finger collet having an inner diameter smaller than an outer diameter of the optical instrument wherein the fingers of the collet spread open during insertion of the optical instrument providing frictional engagement with the outer diameter of the optical instrument. The lock can further comprise a camming member to constrict the optical instrument in the axial position relative to the shaft. The camming member may be a horizontal or vertical camming member. In another aspect, the lock can further comprise a locking collar to rotationally lock the optical instrument. In yet another aspect, the lock can further comprise a locking nut and thread that frictionally engage the optical instrument in the axial position relative to the shaft, or an elastomeric element that facilitates frictional engagement with the optical instrument in the axial position relative to the shaft. 
     In another aspect of the invention, the bladeless obturator further comprises a cap disposed at the proximal end of the shaft. The cap may further comprise a handle. 
     In yet another aspect of the invention, a surgical obturator adapted to separate body tissue is disclosed comprising a shaft extending along an axis between a proximal end and a distal end; and a bladeless tip disposed at the distal end of the shaft having a tapered surface forming proximally into an outer surface, the outer surface including a pair of generally opposed sections, wherein the outer surface has a generally geometric shape in progressive radial cross-sections from a distal cross-section to a proximal cross-section, wherein the pair of generally opposed sections of the outer surface appears as a pair of lines in each of the progressive radial cross-sections, wherein at least one of the pair of lines becomes more arcuate in the progressive radial cross-sections, and wherein the shaft is sized and configured to receive an optical instrument having a distal end to receive an image of the body tissue. With this aspect, the area of the geometric shape increases along the progressive radial cross-sections. 
     In another aspect of the invention, a surgical obturator adapted to separate body tissue is disclosed comprising a shaft having a proximal end and a distal end; and a transparent bladeless tip disposed at the distal end of the shaft having a tapered surface forming proximally into an outer surface, the outer surface extending distally to a blunt point, wherein the shaft is sized and configured to receive an optical instrument having a distal end to receive an image of the body tissue. 
     In yet another aspect of the invention, an optical separator adapted to receive an image of a body tissue and to separate the body tissue is disclosed comprising an optical instrument having a proximal end and a distal end; and a bladeless tip removably attached at the distal end of the optical instrument and having a generally tapered configuration with an outer surface, the outer surface extending distally to a blunt point. 
     These and other features of the invention will become more apparent with a discussion of the various embodiments in reference to the associated drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included in and constitute a part of this specification, illustrate the embodiments of the invention and, together with the description, explain the features and principles of the invention. In the drawings: 
         FIGS. 1A and 1B  illustrate side views of a trocar system including a cannula with associated valve housing, and an obturator with a blunt tip extending through the working channel of the cannula to facilitate placement across the abdominal wall; 
         FIG. 2  is a side elevation view of the blunt tip of the obturator of the invention; 
         FIG. 3  is a side elevation view of the blunt tip taken along line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is an end view taken along line  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a radial cross-section view taken along line  5 - 5  of  FIG. 2 ; 
         FIG. 6  is a radial cross-section view taken along line  6 - 6  of  FIG. 2 ; 
         FIG. 7  is a radial cross-section view taken along line  7 - 7  of  FIG. 2 ; 
         FIG. 8  is a radial cross-section view taken along line  8 - 8  of  FIG. 2 ; 
         FIG. 9  is a radial cross-section view taken along line  9 - 9  of  FIG. 2 ; 
         FIG. 10  is a schematic view illustrating each of the  FIGS. 4-9  super-imposed to facilitate an understanding of the blunt tip and its twisted configuration; 
         FIG. 11  illustrates a side view of a bladeless obturator of the invention having a tip formed as a blunt tapered shape; 
         FIG. 12  illustrates a side view of a bladeless obturator of the invention having a tip formed as a pyramidal shape; 
         FIG. 13  illustrates a side view of a bladeless obturator of the invention having a fully radiused tip; 
         FIGS. 14 and 15  illustrate a side view and a cross-section view, respectively, of the trocar system of  FIGS. 1A and 1B  and further illustrating the insertion of a laparoscope; 
         FIG. 16  illustrates a side view of a bladeless obturator of the invention having a bulbous tip; 
         FIG. 17  illustrates a side view of a bladeless obturator of the invention having a tip with a cutout section; 
         FIG. 18  illustrates a side view of a bladeless obturator of the invention having a shaft with a cutout section; 
         FIG. 19  illustrates a side view of a bladeless obturator of the invention and a cover for the cutout section of the shaft of  FIG. 18 ; 
         FIGS. 20 and 21  illustrate side views of a bladeless obturator of the invention having a laparoscope lock; 
         FIGS. 22 and 23  illustrate side views of a bladeless obturator of the invention including a cap with pistol-grip handle; 
         FIGS. 24 and 25  illustrate the locking mechanism between the bladeless obturator and the trocar seal of the invention; 
         FIGS. 26 and 27  illustrate the release mechanism between the bladeless obturator and the trocar seal of the invention; 
         FIG. 28  illustrates a top view of a laparoscope lock of the invention comprising a multiple-finger collet; 
         FIG. 29  illustrates an optical instrument having a transparent bladeless tip of the invention; 
         FIGS. 30 and 31  illustrate a top view and a side view, respectively, of a laparoscope lock of the invention comprising a camming member; 
         FIGS. 32 and 33  illustrate a top view and a side view, respectively, of a laparoscope lock of the invention comprising a clamping member; 
         FIGS. 34 and 35  illustrate a top view and a side view, respectively, of a laparoscope lock of the invention comprising a locking collar; and 
         FIGS. 36 and 37  illustrate a top view and a side view, respectively, of a laparoscope lock of the invention comprising a locking nut and thread. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     A trocar system is illustrated in  FIG. 1  and is designated by reference numeral  10 . This system includes a cannula  12 , defining a working channel  14 , and a valve housing  16 . The system  10  also includes an obturator  18  having a shaft  21  extending along an axis  23 . A handle  25  is disposed at a proximal end of the shaft  21  while a blunt tip  27  is disposed at a distal end of the shaft  21 . The shaft  21  of the obturator  18  is sized and configured for disposition within the working channel  14  of the cannula  12 . With this disposition, the obturator  18  can be placed across a body wall such as the abdominal wall to provide the cannula  12  with access across the wall and into a body cavity, such as the peritoneal or abdominal cavity. The blunt tip  27  serves to direct the obturator  18  through the abdominal wall and the peritoneum, and can be removed with the obturator  18  once the cannula  12  is operatively disposed with the working channel  14  extending into the abdominal cavity. The diameter of the shaft  21  can range from about 3 mm to about 20 mm and is designed to fit within a trocar seal and the cannula  12 . 
     In accordance with the present invention, the tip  27  is provided with a blunt tip configuration. The blunt tip  27  of the invention takes into account the anatomical configuration of the abdominal wall with an improved structural design and method of insertion. To fully appreciate these aspects of the invention, it is helpful to initially discuss the anatomy associated with the abdominal wall. The abdominal wall typically includes a skin layer and a series of muscle layers, in addition to fat and fascia. The muscle layers are each defined by muscle fibers that extend generally parallel to each other in a direction that is different for each of the layers. For example, fibers of a first muscle layer and a second muscle layer may extend in directions that are generally 90 degrees off of each other. 
     Having noted the directional nature of the muscle fibers, it can be appreciated that such a structure may be separated or divaricated by an obturator having a blunt tip. The blunt tip may also include a twisted rectangular configuration to facilitate movement between the muscle fibers and layers. That is, the blunt tip is capable of being moved generally parallel to and between the fibers associated with a particular muscle layer. 
     As described earlier, the fibers of the muscle layers may be oriented at different angles to each other such that proper alignment of the tip  27  for separation of one layer may not necessarily result in proper alignment for separation of the next layer. For at least this reason, the obturator  18  has a blunt tip  27  to direct the obturator  18  through the different layers and a rectangular configuration that is twisted slightly so that separation of a first layer begins to rotate the distal end of the blunt tip  27  into proper orientation for separation of the next layer. 
     The twisted configuration of the blunt tip  27  also causes the blunt tip  27  to function, for example, with the mechanical advantage of a screw thread. With this configuration, an exemplary method of placement requires that the user grip the handle  25  of the obturator  18  and twist it about the axis  23 . This twisting motion in combination with the screw configuration of the blunt tip  27  converts radial movement into forward movement along the axis  23 . Thus, the user applies both a forwardly directed force as well as a radial force to move the trocar system  10  in a forward direction. 
     The twisted configuration of the blunt tip  27  is most apparent in the side elevation views of  FIGS. 2 and 3 . In this embodiment, the blunt tip  27  comprises generally of eight surfaces: two opposing surfaces  50  and  52 , separated by two side surfaces  54  and  56 , two end surfaces  58  and  59 , a generally tapered surface  60  formed in surfaces  50  and  52  around axis  23  and extending beyond end surfaces  58  and  59 , and a blunt surface  62 . 
     The surfaces  50  and  52 , side surfaces  54  and  56 , and tapered surface  60  generally define the cross-section of the blunt tip  27  from blunt surface  62  to proximal end  61 . This configuration can best be appreciated with reference to the cross-section views of  FIGS. 4-9 . In  FIG. 4 , the distal end of the blunt tip  27  is shown with a circle  64  having the smallest circular area and a rectangle  63  having the greatest length-to-width ratio. The rectangle  63  has a twisted, S-shaped configuration at end surfaces  58  and  59 . 
     As views are taken along progressive proximal cross-sections, it can be seen that the circle  64  becomes larger and the rectangle  63  becomes less twisted, and the width increases relative to the length of the rectangle  63 . The spiral nature of the blunt tip  27  is also apparent as the circle  64  and rectangle  63  move counterclockwise around the axis  23 . This is perhaps best appreciated in a comparison of the circle  64 , the rectangle  63  and the side surfaces  54  and  56  in  FIG. 6  relative to that in  FIG. 5 . With progressive proximal positions, the circle  64  begins to expand with increasing circular area and the rectangle  63  begins to widen with a reduction in the ratio of length to width. The long sides  63 ′ of the rectangle  63  also tend to become more arcuate as they approach a more rounded configuration most apparent in  FIGS. 8 and 9 . That is, the circle  64  and the rounded rectangle  63  become more circular with progressive proximal positions. Furthermore, the circle  64  expands at a lesser rate than the rectangle  63 , which eventually absorbs the circle  64  as shown in  FIGS. 8 and 9 . In these figures, it will also be apparent that the rotation of the rectangle  63  reaches a most counterclockwise position and then begins to move clockwise. This is best illustrated in  FIGS. 7-9 . This back and forth rotation results from the configuration of the side surfaces  54  and  56 , which in general are U-shaped as best illustrated in  FIGS. 2 and 3 . 
     The ratio of the length to width of the rectangle  63  is dependent on the configuration of the side surfaces  54  and  56 , which define the short sides of the rectangle  63  as well as the configuration of the surfaces  50  and  52 , which define the long sides of the rectangle  63 . Again with reference to  FIGS. 2 and 3 , it can be seen that the side surfaces  54  and  56  are most narrow at the end surfaces  58  and  59 . As the side surfaces  54  and  56  extend proximally, they reach a maximum width near the point of the most counterclockwise rotation, shown generally in  FIG. 8 , and then reduce in width as they approach the proximal end  61 . Along this same distal to proximal path, the surfaces  50  and  52  transition from a generally flat configuration at the end surfaces  58  and  59  to a generally rounded configuration at the proximal end  61 . 
     In the progressive views of  FIGS. 5-7 , the circle  64  is further designated with a lower case letter a, b or c, respectively; similarly, the rectangle  63  and the side surfaces  54  and  56  are further designated with a lower case letter a, b, c, d or e, respectively, in  FIGS. 5-9 . In  FIG. 10 , the circles  64 ,  64   a - 64   c , the rectangles  63 ,  63   a - 63   e  and the side surfaces  54 ,  54   a - 54   e  and  56 ,  56   a - 56   e  are superimposed on the axis  23  to show their relative sizes, shapes and angular orientations. 
     With a generally tapered configuration at the distal end and a rectangular configuration at a distal portion of the tip, the tip  27  appears much like a flathead screwdriver having a blunt tip. More particularly, the tip  27  includes a tapered structure extending outward from the end surfaces  58  and  59  that serves to direct the obturator  18  through the tissue fibers. 
     In one aspect, the lengths of the end surfaces  58  and  59  may be aligned parallel with the fibers of each muscle layer. A simple back and forth twisting motion of the blunt tip  27  tends to separate the fibers along natural lines of separation, opening the muscle layer to accept the larger diameter of the cannula  12 . Once the first layer is substantially separated, the tapered and twisted configuration of the blunt tip  27  directs and turns the rectangle  63  more into a parallel alignment with fibers in the next layer. Again, the blunt tip  27  and the twisting or dithering motion facilitates an easy separation of the fibers requiring a significantly reduced insertion force. 
     The invention facilitates a unique method of separating tissue and can be applied to any object with a blunt tip and generally flat sides. In particular, the device of the invention can be operated by rotating in alternating clockwise and counterclockwise directions while applying a downward force. When rotating in alternating directions, the tissue is moved apart and a larger opening is created for a profile of greater cross-sectional area to follow. This process continues safely as the device enters the peritoneal cavity and moves to its operative position. 
     When the cannula  12  is ultimately removed, the size of the opening left in the tissue is minimal. Importantly, this opening is left with a small defect that does not require suturing due to a dilating effect caused by the mere separation of fibers. Since there are no sharp blades, sharp edges or piercing points to cut tissue fibers, the healing process is shortened. It is appreciated that in other aspects of the invention, the tip of the bladeless obturator  18  can be formed as a generally tapered shape  27   a  with a blunt distal end as illustrated in  FIG. 11 , as a pyramidal shape  27   b  with a blunt distal end and blunt edges as illustrated in  FIG. 12 , and as a fully radiused tip  27   c  for insertion through flaccid tissue or an existing body orifice such as the urethra as illustrated in  FIG. 13 . 
     The blunt tip  27  can be formed from a translucent or a transparent material. The blunt tip  27  can be formed from a plastic material or a glass material. In one aspect, the shaft  21  and the tip  27  are formed from a transparent polycarbonate material. 
     Referring to  FIGS. 14 and 15 , the bladeless obturator  18  of the invention is designed to accommodate the insertion of a conventional laparoscope  30 . In particular, the shaft  21  of the bladeless obturator  18  is hollow to allow for the insertion of the laparoscope  30  at an opening  32 . The shaft  21  is sized and configured to allow the laparoscope  30  to slide within proximity of the tip  27  thus providing a viewing area through the tip  27 . An endoscopic video camera (not shown) is typically connected to the laparoscope  30  and this combination is connected to a video monitor. By enabling the positioning of the conventional laparoscope  30  within the tip  27  of the bladeless obturator  18 , it is possible to visually observe body tissue as it is being separated by the trocar system  10 . Visualization of body tissue as it is being separated by the trocar system  10  allows a surgeon to monitor the advancement of the trocar system  10  and to avoid traumatizing vessels or organs. For example, during a laparoscopic cholecystectomy, a trocar is usually placed through the umbilicus of the patient. The placement of this trocar is typically performed in a blind fashion in that the surgeon cannot see where the tip of the trocar is as it is advanced through the abdominal wall and into the abdominal cavity of the patient. This results in a high degree of risk that the trocar may be inadvertently advanced too far into the abdomen of the patient resulting in trauma to vital organs and/or vessels. By providing a trocar system with visualization properties, this risk is diminished as the surgeon is better able to determine when the trocar has traversed the abdominal wall. 
     It is appreciated that the tip  27  may be generally hollow or it may be substantially solid to receive the distal end of the laparoscope  30 . In another aspect, the tip  27  may be a solid tip. The tip  27  may further comprise at least one portion that is marked differently from the rest of the tip to serve as an indicator, for example, of depth as the tip  27  is being inserted into the body tissue. The at least one portion may be opaque or marked with a different color from the rest of the tip  27 . 
     The shaft  21  and the tip  27  of the bladeless obturator  18  can accommodate a laparoscope with a non-angled lens, also known as a 0° laparoscope. The shaft  21  and the tip  27  can also accommodate a laparoscope with an angled lens such as a 30° laparoscope. The tip  27  is designed such that when either a 0° laparoscope or a 30° laparoscope is inserted therein, the lens of the laparoscope extends beyond a distal edge  36  of the cannula  12  thereby providing a clear and unobstructed view through the tip  27 . The tip  27  further includes a ledge  39  that properly engages either the 0° laparoscope or the 30° laparoscope. 
     It should be noted that conventional trocars with visualization properties typically require a 0° laparoscope for insertion of the trocars and a 30° laparoscope for viewing anatomical structures during the remainder of the laparoscopic procedure. This requires the operating staff to provide two laparoscopes for the laparoscopic procedure, which increases hospital inventory costs and surgical preparation costs relating to cleaning and sterilization of the laparoscopes. In addition, because two laparoscopes are required for the laparoscopic procedure, there is additional operating room time required during the surgical procedure to transfer the endoscopic video camera from the 0° laparoscope to the 30° laparoscope which results in increased operating room costs for the hospital. 
     The bladeless obturator of the present invention provides a clear unobstructed view of body tissue through either a 0° or a 30° laparoscope, therefore obviating the need for a hospital to carry the additional inventory required to provide two laparoscopes for each laparoscopic surgical procedure, and obviating the need for a hospital to clean and sterilize a second laparoscope for each laparoscopic surgical procedure, and obviating the need to transfer the endoscopic video equipment from one laparoscope to the other laparoscope during each laparoscopic surgical procedure. Referring to  FIG. 16 , the shaft  21  may include a tip with a bulbous section  27   d  to better accommodate the distal end of the angled lens laparoscope. By adding the bulbous section  27   d , the distal end of the angled lens laparoscope would be closer to the tip of the obturator thereby improving visualization. 
     In yet another aspect of the invention, the bladeless obturator can include integral fiber optic light fiber elements and an integral imaging element within the shaft and the tip of the obturator. The bladeless obturator with integral imaging means can be formed of reusable or disposable materials. 
     The bladeless obturator  18  can be constructed as a single component or as multiple components such as the shaft  21  and the tip  27 . If the obturator  18  is constructed as a single component, then it can be formed from either disposable or reusable materials. If the obturator  18  is constructed as two or more components, then each component can be formed from either disposable or reusable materials as desired for a particular configuration. In one aspect, the obturator  18  is constructed from a single reusable material such as metal (e.g., stainless steel) or an autoclavable polymer to facilitate re-sterilization. In another aspect, the obturator  18  is formed from a transparent steam sterilizable reusable plastic material such as polyphenylsulfone or polyetherimide. The blunt tip  27  can also be coated or otherwise constructed from a soft elastomeric material. In such a case, the material can be a solid elastomer or composite elastomer/polymer. 
     It is further appreciated that the shaft  21  can be formed so as to be partially or fully flexible. With this configuration, the obturator  18  can be inserted through a passageway containing one or more curves of virtually any shape. A partially or fully flexed obturator  18  can then be used with a flexible cannula  12  allowing greater access to an associated body cavity. 
     The obturator  18  can include a separately molded tip  27  and a molded or extruded shaft  21  with the two components, as explained above, comprising of the same material or different materials. The tip  27  can then be attached to the shaft  21  by adhesive bonding, ultrasonic welding, snap-fitting, or with a shrink tube. The tip  27  can also be overmolded over the shaft  21  to mechanically lock the two components together. The tip  27  can be formed from a transparent material such as polycarbonate to enable visualization while the shaft  21  can be formed from either an opaque material or a transparent material. The shaft  21  can also be formed from a metal material. 
     In another aspect, the obturator  18  can include a disposable tip that is releasably attached to a reusable shaft  21 . In this aspect, a new tip  27  can be used for each procedure to provide optimal visualization through the tip  27  of the obturator  18  during each procedure. 
     Referring to  FIG. 17 , there is shown a shaft  18   e  in accordance with another aspect of the invention including a cutout section  100   e  in the tip portion  27   e  that enables direct visualization of the body tissue as the tip  27   e  separates tissue fibers. By providing an obturator with cutout sections, the reflection of light from the laparoscope is minimized and the visibility of the tissue through the laparoscope is improved as compared to a design where visualization occurs through a plastic or glass window. It is appreciated that the shaft  21   e  can include a single or a plurality of cutouts  100   e  in the tip  27   e  or along the shaft of the obturator. 
     Referring to  FIG. 18 , there is shown a shaft  21   f  in accordance with another aspect of the invention having a cutout portion  100   f  along the axial axis of the shaft  21   f . The shaft  21   f  has a cross-section of about ½-circle to about ¾-circle and the cutout portion  100   f  has a cross-section of about ½-circle to about ¼-circle. An advantage of this aspect of the invention is the wall of the shaft  21   f  can be a little thicker as a result of the cutout section, which makes injection molding of the shaft easier. 
     Referring to  FIG. 19 , there is shown a cover  102   f  that can be attached over the cutout portion  100   f  of the ½-circle shaft  21   f  as shown in  FIG. 18 . In particular, a polycarbonate cover also with a ½-circle shaped cross-section can be attached to the shaft to form a tubular cross-section. An advantage of molding the tubular shaft  21   f  in two pieces is increased manufacturability of the shaft  21   f . The cover  102   f  can be attached to the shaft  21   f  with an adhesive bond, an ultrasonic weld, a snap-fit, or with a shrink tube. 
     In another aspect, the obturator can be formed from two clam-shell components each including one-half of the shaft and tip configuration along the axial axis of the obturator. The two components can then be affixed together using an adhesive bond, an ultrasonic weld, an outer shrink tube, or a snap fit. 
     Referring to  FIGS. 20 and 21 , another feature of the bladeless obturator  18  of the invention is it is designed to frictionally lock the laparoscope  30  in place using a laparoscope lock  40 , which can be formed within the handle  25 . More specifically, the laparoscope lock  40  prevents the laparoscope  30  from moving axially relative to the shaft  21  of the obturator  18  during handling within the sterile field and during insertion through a body wall but enables the laparoscope  30  to rotate freely relative to the shaft  21 . This rotation of the lock  40  enables the trocar system  10  to be twisted during insertion into and through the abdominal wall while maintaining the laparoscope  30  in a fixed rotational position that provides for a stable viewing image on the video monitor. 
     The conventional obturators with visualization properties include means for locking the laparoscope in place but these obturators lock the laparoscope both axially and rotationally. A drawback of the conventional devices is the viewing image on the video monitor is unstable if the trocar is twisted during insertion. More specifically, with prior art obturator laparoscope locks, if the trocar is twisted back and forth in a clockwise and counter-clockwise fashion, the laparoscope also moves clockwise and counter-clockwise with the trocar resulting in an oscillating and disorienting viewing image on the video monitor. The laparoscope lock  40  of the present invention improves visualization and enables a more precise placement of the trocar within the body tissue and across the body wall as compared to obturators of the prior art while preventing inadvertent axial movement of the laparoscope during handling and use. 
     In another aspect of the invention as illustrated in  FIGS. 20 and 21 , the bladeless obturator  18  further comprises a cap  42  that can be snap-fitted onto the proximal end of the obturator shaft  21 , after which the laparoscope lock  40  can be snap-fitted onto the end of the cap  42 . Both the cap  42  and the lock  40  can be formed of a plastic material such as polycarbonate. The obturator cap  42  can be provided with and without a pistol-grip handle. The handled version of the bladeless obturator provides a pistol-grip to ease insertion of the trocar system as illustrated in  FIGS. 22 and 23 . The pistol-grip handle is designed to nest into the handle on the trocar seal to prevent excessive flexure of the handle during insertion of the trocar as illustrated in  FIG. 23 . More particularly, the handled bladeless obturator includes three components comprising of an obturator shaft  21   b , an obturator cap  42   b  having a pistol-grip handle  26   b , and a laparoscope lock  40   b , all of which can be injection molded out of polycarbonate. The pistol-grip handle  26   b  can be formed with two components frictionally fitted together with, for example, interference pins. The interference pins can be fitted into holes in the handle  26   b  to affect a frictional lock between the two components. 
     Referring to  FIG. 24 , the bladeless obturator  18  is designed to releasably attach to a trocar seal  17  via two cantilever snap-fits  70   a ,  70   b . As the obturator  18  is inserted into the trocar seal  17  and cannula  12 , the snap-fits  70   a ,  70   b  passively engage the trocar seal  17  and serve to axially lock the obturator  18  to the trocar seal  17  and cannula  12  ( FIGS. 24 and 25 ). To release the obturator  18  from the trocar seal  17  and cannula  12 , outboard tabs  72   a ,  72   b  on the obturator cap  42  are depressed inwardly and the obturator  18  is then free to be slidably removed as illustrated in  FIGS. 26 and 27 . Referring back to  FIGS. 20 and 21 , the bladeless obturator  18  includes axial key members  74  at its proximal end which are designed to mate with axial keyways on the trocar seal  17 . As the bladeless obturator  18  is inserted into the trocar seal  17  and cannula  12 , the obturator  18  is rotated slightly to align the axial key members  74  with the axial keyways and then advanced until the snap-fits  70   a ,  70   b  engage the trocar seal  17 . The axial key members  74  serve to rotationally lock the obturator  18  to the trocar seal  17 . 
     Referring to  FIG. 28 , there is shown another embodiment of the laparoscope lock  40   c  comprising a multiple-finger collet  80   c  comprising a plurality of fingers  82   c . The multiple-finger collet  80   c  has an inner diameter that is smaller than the outer diameter of the laparoscope. The fingers  82   c  of the collet  80   c  spread open during insertion of the laparoscope providing frictional engagement with the outer diameter of the laparoscope. The laparoscope lock  40   c  is free to rotate on an obturator cap  42   c , and allows the laparoscope to freely rotate relative to the shaft of the bladeless obturator. 
     Referring back to  FIGS. 20 and 21 , the obturator shaft  21  of the bladeless obturator  18  can be configured with a barb  76  at its proximal end. The barb  76  is vertically slotted to enable the shaft  21  to flex during assembly. The obturator shaft  21  may also include a plurality of keys (not shown) near its proximal end. The obturator cap  42  is configured to axially slide over the barb  76  on the obturator shaft  21  to affect a one-way snap-fit lock between the two components. This snap-fit prevents the removal of the obturator cap  42  from the obturator shaft  21 . The obturator cap  42  may further include keyways (not shown) that engage the keys on the obturator shaft  21  to rotationally index the components together. The obturator cap  42  may further include a second barb (not shown) at its proximal end. The laparoscope lock  40  may include a plurality of tabs (not shown) that are designed to spread and axially slide over the second barb on the obturator cap  42  to affect a one-way snap-fit lock between the obturator cap  42  and the laparoscope lock  40 . This snap-fit prevents the axial removal of the laparoscope lock  40  from the obturator cap  42 . The laparoscope lock  40  is free to rotate relative to the obturator cap  42 . 
     Referring to  FIG. 29 , there is shown another aspect of the invention of a laparoscope  30   a  having a tip  33   a  configured similar to that of the tip  27  of the bladeless obturator  18  described above, the tip  33   a  being adapted to snap-fit or frictionally engage the end of the laparoscope  30   a . With this configuration, the combination of the tip  33   a  and the laparoscope  30   a  serve to form an optical obturator having a blunt tip. Once the trocar is inserted and the laparoscope removed from the trocar seal and cannula, the bladeless tip  33   a  can then be removed from the laparoscope  30   a . The bladeless tip  33   a  can be formed from either a disposable or reusable transparent material. The bladeless tip  33   a  can be temporarily or permanently affixed to the scope  30   a  by any of the known methods of attaching the two components together as explained above. 
     Referring to  FIGS. 30 and 31 , there is shown a laparoscope lock  40   d  in accordance with another embodiment of the invention including an active lock comprising a camming member  43   d . With this type of lock, the laparascope would first be inserted into the shaft of the obturator and then the lock  40   d  would be activated to lock the laparoscope in an axial position relative to the shaft. The lock  40   d  can either rotate freely to enable the laparoscope to rotate freely relative to the shaft or the lock  40   d  can be rotationally fixed to prevent the laparoscope from rotating relative to the shaft. In another aspect as illustrated in  FIGS. 32 and 33 , a lock  40   e  can include an active lock comprising a clamping member  45   e . With this type of lock, the laparascope would first be inserted into the shaft of the obturator and then the lock would be activated to lock the laparoscope in an axial position relative to the shaft. The lock  40   e  can either rotate freely to enable the laparoscope to rotate freely relative to the shaft or the lock  40   e  can be rotationally fixed to prevent the laparoscope from rotating relative to the shaft. 
     Referring to  FIGS. 34 and 35 , there is shown a lock  40   f  in accordance with another embodiment of the invention including an active lock comprising a locking collar  46  positioned eccentrically with respect to the axis of the obturator so that as the locking collar  46  is turned, a frictional engagement with the laparoscope is affected. The laparoscope would first be inserted into the locking collar  46  and the shaft of the obturator, the locking collar  46  can then be turned to frictionally engage the laparoscope. The laparoscope lock  40   f  can either rotate freely to enable the laparoscope to rotate freely relative to the shaft or the laparoscope lock  40   f  can be rotationally fixed to prevent the laparoscope from rotating relative to the shaft. 
     In another aspect of the invention as illustrated in  FIGS. 36 and 37 , there is shown a laparoscope lock  40   g  including an active lock comprising of a locking nut  48  and a thread. The threaded portion of the lock  40   g  has flexible elements similar to those on a collet. The laparoscope would first be inserted into the threaded portion of the lock  40   g  and the nut then rotated clockwise to collapse the flexible elements to frictionally engage the laparoscope. To release the laparoscope, the nut is rotated counter-clockwise. 
     In another aspect, the laparoscope lock can include a lock that includes an elastomeric element. The addition of the elastomeric element can enhance the frictional engagement with the laparoscope. An example of such an elastomeric element is a silicone O-ring sized with an inside diameter smaller than the outside diameter of the laparoscope. The laparoscope lock can either rotate freely to enable the laparoscope to rotate freely relative to the shaft or the laparoscope lock can be rotationally fixed to prevent the laparoscope from rotating relative to the shaft. 
     In yet another aspect, the obturator  18  can also be used as an insufflation needle having a passageway and valve to administer carbon dioxide or other insufflation gas to the peritoneal cavity. The obturator  18  can also be used with an insufflation needle cannula in which case removal of the obturator  18  upon entry would allow for rapid insufflation of the peritoneal cavity. 
     In another aspect of the invention, the bladeless obturator can be formed with a 2-3 mm outer diameter and with a small thru-hole at its distal end. The bladeless obturator can be used in conjunction with a miniaturized laparoscope to provide initial access into a hollow body cavity. Once access is obtained, the laparoscope can be removed from the bladeless obturator and an insufflation gas such as carbon dioxide can be dispensed through the obturator into the hollow body cavity. The bladeless obturator can also include holes in the tip portion to enhance the flow of insufflation gases though the obturator. More particularly, the bladeless obturator can be formed with a 2-3 mm outer diameter and used in conjunction with a miniaturized laparoscope to provide initial access into a hollow body cavity. After access is obtained, the bladeless obturator can be removed from the trocar cannula and an insufflation gas such as carbon dioxide can be dispensed though the cannula and into the hollow body cavity. 
     It will be understood that many modifications can be made to the disclosed embodiments without departing from the spirit and scope of the invention. For example, various sizes of the surgical device are contemplated as well as various types of constructions and materials. It will also be apparent that many modifications can be made to the configuration of parts as well as their interaction. For these reasons, the above description should not be construed as limiting the invention, but should be interpreted as merely exemplary of preferred embodiments.