Abstract:
A suturing instrument and method for placing mattress stitches in soft tissues is described. An elongate shaft with a stationary jaw and a moveable jaw disposed at the distal end is coupled to a handle grip at the proximal end configured to manipulate the jaws into open and closed positions. The jaws are configured to allow for atraumatic grasping of soft tissues. The stationary jaw is comprised of a serrated face incorporating apertures through which needles attached to opposite ends of a single strand of suture material may be driven out into and through grasped tissue. The serrated upper jaw is configured with needle catch adapted to accept and capture the needles and suture. The handle is released to open the moveable jaw, the instrument may be withdrawn, trailing the suture, and leaving a mattress stitch in the grasped tissue.

Description:
This application is related to co-pending application Ser. No. 09/475,495, filed on Dec. 30, 1999, and entitled Method and Apparatus for Attaching Connective Tissues to Bone Using a Knotless Suture Anchoring Device, and to co-pending application Ser. No. 09/515,360, filed on Feb. 29, 2000, and entitled Single-Tailed Suturing Method and Apparatus, both of which are herein expressly incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method and apparatus for placing sutures in tissue, and more particularly to a method and device for arthroscopic repair of a torn rotator cuff. 
     Suturing of body tissues is a time consuming aspect of most surgical procedures. Many surgical procedures are currently being performed where it is necessary to make a large opening to expose an area of the body that requires surgical repair. Endoscopes are available for viewing certain interior regions of the body through a small puncture wound without exposing the entire body cavity. These instruments can be used in conjunction with specialized surgical instrumentation to detect, diagnose, and repair areas of the body that were previously only able to be repaired using traditional “open” surgery. 
     In the past, there have been many attempts to simplify the surgeon&#39;s task of driving a needle carrying suture material through body tissues to approximate, ligate and fixate them. Many prior disclosures, such as described in U.S. Pat. No. 919,138, to Drake et al., issued Apr. 20, 1909, employ a hollow needle driven through the tissue with the suture material passing through the hollow center lumen. The needle is withdrawn leaving the suture material in place, and the suture is tied, completing the approximation. A limitation of these types of devices is that they are particularly adapted for use in open surgical procedures where there is room for the surgeon to manipulate the instrument. 
     Others have attempted to devise suturing instruments that resemble traditional forceps, such as U.S. Pat. No. 3,946,740 to Bassett, issued Mar. 30, 1976. These devices pinch tissue between opposing jaws and pass a needle from one jaw through the tissue to the other jaw, where grasping means pull the needle and suture material through the tissue. A limitation of these designs is that they also are adapted primarily for open surgery, in that they require exposure of the tissues to be sutured in order that the tissue may be grasped or pinched between the jaws of the instrument. This is a severe limitation in the case of endoscopic surgery. 
     The term “endosurgery” means endoscopic surgery or surgery performed using an endoscope. In conjunction with a video monitor, the endoscope functions as the surgeon&#39;s surrogate eyes for the purpose of performing the surgical procedure. Operations using an endoscope are significantly less invasive when compared to traditional open surgery. Patients usually return home the next day or in some cases, the same day of the endosurgical procedure. This is in contrast to standard open surgical procedures where a large incision divides the muscle layers and allows the surgeon to directly visualize the operative area. Patients may stay in the hospital for 5 to 6 days or longer following open surgery. In addition, after endosurgical procedures, patients often return to work within a few days versus the traditional 3 to 4 weeks recuperative period following open surgery. 
     Access to the operative site using endosurgical or minimally invasive techniques is accomplished by inserting small tubes called trocars into a body cavity. These tubes have a diameter of, for example, between 3 mm and 30 mm and a length of about 150 mm (6 inches). There have been attempts to devise instruments and methods for suturing within a body cavity through these trocar tubes. 
     Such an instrument is disclosed in U.S. Pat. No. 4,621,640 to Mulhollan et al., issued Nov. 10, 1986. Mulhollan et al. describe an instrument that may be used to hold and drive a needle, but make no provision for retrieval of the needle from the body cavity, nor the completion of the suture by tying. The instrument disclosed in the Mulhollan et al. patent is limited, in that the arc through which the needle must be driven is perpendicular to the axis of the device. 
     Another such instrument intended for endoscopic use is described by U.S. Pat. No. 4,935,027 to Yoon, issued Jun. 19, 1990. This instrument uses oppositional hollow needles or tracks pushed through the tissue and co-apted to create a tract through which the suture material is pushed. It is not clear from the disclosure how these curved tracks would be adapted to both be able to pierce the tissue planes illustrated, parallel to the tips of the tracks, and be curved toward each other to form the hollow tract. 
     Yet another instrument and method is shown in U.S. Pat. No. 4,923,461 issued May 8, 1990 and U.S. Pat. No. 4,957,498 issued Sep. 18, 1990, both to Caspari. Caspari discloses an endoscopic instrument suitable for use through a trocar, that resembles the Yoon approach, but with a single hollow needle on one of a set of oppositional jaws. The jaws simultaneously close, grasping the tissue. The jaw opposite the hollow needle has a window through which the hollow needle passes as the jaws close, freeing the lumen of the hollow needle from the tissue. Much like the Yoon patent, a suture or suture snare is pushed down through the lumen and retrieved from the suture site, the jaws released, and the suture pulled back out through the trocar. This device may be used to place simple stitches in tissues that have been mobilized and have an edge accessible to the jaws. A limitation of the device is the manipulation that must be done with the snare if a suture other than a monofilament is used. 
     Another instrument specifically adapted for the repair of a tom anterior cruciate ligament or for meniscal repair is disclosed in U.S. Pat. No. 4,836,205 to Barrett. The Barrett patent combines in a single instrument the functions of grasping the tissue to be sutured and the passing of the needles through that tissue. It is to be understood that this instrument is designed for use specifically under endoscopic view, and through trocars as previously described. A fairly generic endoscopic grasper is disclosed that has been adapted to allow for a hollow lumen from the handle of the grasper down to the distal tip of the grasper jaws. An elongate needle of 8 to 10 inches in length may be passed through this hollow lumen. The needle, being significantly longer than the grasper, is introduced through the handle of the grasper, and may be driven through the tissue being held in the grasping jaws of the device. The needle is then retrieved from the tissue via a trocar port placed substantially opposite the port through which the grasper is introduced. If a mattress stitch is desired, two needles attached to opposite ends of a suture are both passed through the tissue and retrieved. A limitation of this device is that there must be both visual and physical access to both sides of the tissue flap to be sutured. This requires trocars to be placed opposite each other and roughly on a line intercepting the tissue. This is a severe limitation in the instance of shoulder repair, and specifically in repair of the rotator cuff. 
     There have been other attempts to improve the methods of tissue repair. These include the development of staplers and anchoring devices. In response to some of the aforementioned problems in placing sutures in tissues endoscopically, manufacturers have developed tissue staplers. These devices utilize stainless steel or titanium staples that are constructed much like the staples used to hold papers together. The major disadvantage of these kinds of staplers is that they leave metal in the body. For some tissues this is not a problem, however in some procedures, metal staples left within the tissues can be a major hindrance to the healing process. 
     In orthopedic surgery, many different designs for bone anchors have been developed. These anchors allow soft tissues to be reattached to bone, and simplify the process by removing the need to create a trans-osseous tunnel. Trans-osseous tunnels are created in bones to allow suture material to be threaded through and tied across the bony bridge created by tunnels after it has been placed through the soft tissues and tied with conventional knots. Anchors fabricated from stainless steel or titanium are commonly used in joint reconstructions, and because the metal is contained in the bone, it does not typically cause a problem with healing. 
     While endoscopy has certainly found favor with many physicians as an alternative operative modality, the advanced skill set and operative time necessary to become an efficient and practiced endoscopist have proven to be a challenge for a large portion of the surgical community. The cost pressures brought about by large scale patient management (the continued rise and success of health maintenance organizations or HMO&#39;s) have also caused the surgical community to carefully evaluate the overall costs and long-term outcomes of some of the procedures that have been tried via an endoscopic approach. While the laparoscopic cholecystectomy (gall bladder removal) has well proven its worth in the past 8-10 years, many other procedures have not shown similar cost effectiveness and positive long-term outcomes. 
     Hence, alternatives have been sought to bridge the gap between skill and equipment intensive endoscopic surgery and more familiar open surgery. As such, under the broad umbrella of “minimally invasive surgery” which would include endoscopic surgery, a relatively new approach called “mini-incision surgery” has begun to emerge. This approach uses the principles of traditional open surgery, along with some of the equipment advances of endoscopy in an attempt to provide the patient with the best of both worlds. 
     Perhaps the most visible of these new approaches is the emergence of minimally invasive heart surgery, both for coronary bypass and for valve replacement. Techniques and tools for cardiovascular surgery have begun to be used that allow the heart surgeon to perform procedures through small incisions between the ribs that previously required a massive incision and splitting of the sternum to gain access to the heart. 
     In a similar way, orthopedic surgeons have begun to explore alternatives to the traditional open approach for the many indications requiring reconstruction of some aspect of the shoulder. As they did in adopting minimally invasive approaches to knee repair and re-construction, the use of either an endoscope or a “mini-open” approach is gaining in popularity with surgeons, patients and third party payers. 
     It is an increasingly common problem for tendons and other soft, connective tissues to tear or to detach from associated bone. One such type of tear or detachment is a “rotator cuff” tear, causing pain and loss of ability to elevate and externally rotate the arm. Complete separation can occur if the shoulder is subjected to gross trauma, but typically, the tear begins as a small lesion, especially in older patients. 
     The rotator cuff of a shoulder joint is made up of a combination of the distal tendinous portion of four muscles, supraspinatus and subspinatus, subscapularis and teres minor. The cuff is attached to the upper, anterior and posterior faces of the trochiter by covering the upper pole of the humeral head. Proper functioning of the tendinous cuff, 3 to 4 millimeters thick, depends on the fundamental centering and stabilizing role of the humeral head with respect to sliding action during anterior and lateral lifting and rotation movements of the arm. 
     The musculotendinous cuff passes under an osteofibrous arch, which is made up from the front to the rear by a portion of the acromion, the coracoacromial ligament and the coracoid process, thereby forming a canal. A sliding bursa passes between the musculotendinous cuff and the walls of the osteofibrous arch. Therefore, there is a potential and sometimes detrimental interaction between the musculotendinous cuff and the acromiocoracoidian arch, particularly during lateral and anterior lifting movements of the arm. The repeated rubbing of the cuff against the walls of the osteofibrous arch results in wearing of the tendinous cuff by progressive abrasion. The rubbing can be increased, inasmuch as arthosis lesions with severe osteophytes may thicken the walls of the aforementioned arch, becoming more aggressive as the cuff gets older. 
     With time, gradual thinning is brought about, often resulting in a trophic perforation (less than 1 cm 2 ) of the cuff, particularly in the hypo-vascularized and fragile area where the supraspinatus muscle is joined. A fall may provide a more extensive rupture by disjunction of the supraspinatus muscle, with extension towards the front (subscapularis muscle) or the rear (subspinatus muscle). The degenerative rupture of the rotator or musculotendinous cuff may be of a varied size: 
     grade 1—perforation (less than 1 cm 2 ) reaching the supraspinatus muscle; 
     grade 2—supraspinatus rupture (greater than 1 cm 2 ); 
     grade 3—massive rupture concerning the supraspinatus, subspinatus, subscapularis muscles and sometimes the teres minor muscle. 
     It is possible to carry out surgery to reconstruct the rotator cuff. This is done by re-covering the humeral head, giving back to the cuff its capturing and stabilizing role and re-establishing a harmonious scapulohumeral rhythm. Reconstruction requires excision of the coracoacromial ligament and cleaning of the subacromial space, including suppression of the arthrosis legions and thinning of the anterior portion of the acromion. 
     The typical course for repair of a tom rotator cuff today is to do so through an open incision. This approach is presently taken in almost 99% of rotator cuff repair cases. Two types of open surgical approaches are employed for repair of the rotator cuff, one known as the “classic open” and the other as the “mini-open”. The classic open approach requires a large incision of 6 to 9 centimeters (cm) and complete detachment of the deltoid muscle from the acromion to facilitate exposure. Following the suturing of the rotator cuff to the humeral head, the detached deltoid is surgically reattached. Because of this maneuver, the deltoid requires postoperative protection, thus retarding rehabilitation and possibly resulting in residual weakness. Complete rehabilitation takes approximately 9 to 12 months. 
     The mini-open technique, which represents the current growing trend and the majority of all surgical repair procedures, differs from the classic approach by gaining access through a smaller incision of 3 to 5 cm and splitting rather than detaching the deltoid. Additionally, this procedure is typically used in conjunction with arthroscopic acromial decompression. Once the deltoid is split, it is retracted to expose the rotator cuff tear. The cuff is debrided and trimmed to ensure suture attachment to viable tissue and to create a reasonable edge approximation. In addition, the humeral head is abraded or notched at the proposed soft tissue to bone reattachment point, as healing is enhanced on a raw bone surface. A series of small diameter holes, referred to as trans-osseous tunnels, are “punched” through the bone laterally from the abraded or notched surface to a point on the outside surface of the greater tuberosity, commonly a distance of 2 to 3 cm. 
     There are a few different methods for placing the suture material in the supraspinatus tendon. Because one of the most common failure modes for rotator cuff repair lies in the sutures pulling out of the soft tissue, much care is taken to place the sutures such that the most security possible is achieved. This is typically done by using either a mattress stitch or a more complex stitch called a “modified Mason-Allen”. The goal of both of these stitches is to spread the forces imparted by the sutures on the tissues by involving a pledget of tissue between the entry and exit points of the suture ends. The mattress stitch incorporates essentially a “down, over and back up” path for the suture. 
     Finally, the cuff is secured to the bone by pulling the suture ends through the trans-osseous tunnels and tying them together using the bone between two successive tunnels as a bridge, after which the deltoid muscle must be surgically reattached to the acromion. 
     Although the above described surgical technique is the current standard of care for rotator cuff repair, it is associated with a great deal of patient discomfort and a lengthy recovery time, ranging from at least four months to one year or more. It is the above described manipulation of the deltoid muscle together with the large skin incision that causes the majority of patient discomfort and an increased recovery time. 
     Less invasive arthroscopic techniques are beginning to be developed in an effort to address the shortcomings of open surgical repair. Working through small trocar portals that minimize disruption of the deltoid muscle, a few surgeons have been able to reattach the rotator cuff using various bone anchor and suture configurations. The rotator cuff is sutured intracorporeally using instruments and techniques such as the Caspari punch previously described. This creates a simple stitch instead of the more desirable mattress or Mason-Allen stitch. Rather than thread the suture through trans-osseous tunnels which are difficult or impossible to create arthroscopically using current techniques, an anchor is driven into bone at a location appropriate for repair. The repair is completed by tying the cuff down against bone using the anchor and suture. 
     Early results of less invasive techniques are encouraging, with a substantial reduction in both patient recovery time and discomfort. However, as mentioned, this approach places only one loop of suture in the cuff for each anchor, reducing the fundamental strength of the repair. The knots in the tendon can be bulky and create a painful impingement of the tendon on the bone. This is because the knots end up on top of the cuff, in the sub-acromial space, and have the opportunity to rub on the acromion as the arm is raised. Because non-absorbable suture materials are used for these types of repairs, the suture and associated knots are not absorbed into the body, and hence provide a constant, painful reminder of their presence. 
     None of the prior art devices are adaptable to effect the placement of a mattress stitch in grasped tissues, nor are they adaptable to place sutures precisely and controllably while making provision for needle retrieval when using endoscopic techniques. None of the prior art devices make it possible to place a mattress stitch into, for example, the supraspinatus tendon utilizing an endoscopic approach. 
     Accordingly, it would be desirable to provide a family of novel suturing devices that overcomes the above set out disadvantages of prior known devices in a simple and economical manner. In particular, a system which would be capable of creating a mattress stitch in the tendon, using endoscopic techniques, to increase the soft tissue pullout strength would be advantageous, as would a system that does not require the traditional knots to secure the suture to the tendon. 
     SUMMARY OF THE INVENTION 
     Accordingly, a new and novel approach to securing a mattress stitch in a tissue flap has been developed. An instrument that combines the function of both grasping the tissue and passing sutures through the tissue to form a mattress stitch, in an endoscopic environment, is herein described. 
     In the method of the present invention the instrument is inserted through a portal known as a trocar cannula. The portal is created by first making an incision in the skin and then inserting a cannula through the incision to the repair site. The distal end of the instrument is inserted through the cannula under direct visualization from a second trocar cannula that has been previously inserted. The visualization is accomplished via an endoscope, which is well known in the art. The instrument is inserted until the jaws reach, for example, torn rotator cuff tissue. In operation, the distal end of the grasper aspect of the instrument is positioned at the repair site against the tissue to be grasped. The moveable jaw is pivoted toward the stationary jaw by squeezing the handle lever. As the handle lever moves inwardly by pivoting about a pivot pin, a cable attached to the top of the handle lever is drawn rearwardly, proximal of the handle. When the cable is drawn rearwardly, the movable jaw pivots towards the stationary jaw to close the jaws. Once the appropriate section of tissue is isolated and grasped by the jaws, the lever may be locked in its closed position using a latch mechanism. 
     Once the surgeon is satisfied with the placement of the grasper on the grasped tissue, the surgeon can then deploy the suture needles to create a mattress stitch in the tissues, for example, a torn rotator cuff. In operation, the suture needles may be advanced through the grasped tissues by pulling on a trigger. The trigger is attached to a slide cable, and pulling on the trigger draws the slide cable rearwardly towards the proximal end of the instrument, pulling against the force of a return spring. In turn, the slide cable pulls a needle carriage with suture needles releasably held in the carriage. The needle carriage resides within the lower stationary jaw of the instrument, and at the urging of the trigger via the slide cable, is able to move from distal to proximal locations within the jaw. As the carriage moves proximally, the tips of the suture needles begin to clear the distal edge of an aperture created in the lower stationary jaw and begin to penetrate through the underside of the grasped tissue and advance upwardly towards the movable jaw. 
     In one preferred embodiment, the needle carriage is coupled to the needles by a set of tabs that engage shoulders on the needles. The shoulders of the needles are formed by the proximal end of the needle holding the suture, and an outer sleeve that is slidably disposed about a flexible inner ribbon affixed to the proximal end. The ribbon has attached to its distal end a needle tip which limits the distal travel of the outer sleeve and creates the second shoulder at the proximal end of the outer sleeve. 
     In the aforementioned embodiment, the moveable jaw incorporates a passive needle catch. The jaw is constructed with a window in the face of the jaw to allow the needles to penetrate through to a passive catch that incorporates a thin stainless steel membrane with slots configured to capture the tips of the needles. As the suture needles approach the end of the ejection stroke, the distal ends of the needles pass through the upper movable jaw and the capture member. As the needles pass through the upper jaw they begin to separate from the needle carriage. The proximal end of the needles&#39; curved outer sleeve separates from the first tab on the needle carriage, in such a manner that there is no further force pushing on the sleeve to force it through the tissues. The force now pushing on the suture needles is concentrated on the proximal end of the needles. As the needle carriage is advanced further, the needles&#39; curved outer sleeves stay stationary due to the resistance caused by their contact with the tissues. However, the flexible inner ribbon of each needle is free to advance further. The gap between the needles&#39; curved outer sleeves and the proximal end of each needle begins to close until there is no gap at all. At this point the penetrating tip of each needle has extended beyond the distal end of the needle&#39;s curved outer sleeve, exposing the flexible inner ribbon. Once the gap is closed between the proximal end of the needle and the outer sleeve, the needle assembly will again continue to advance as one unit through the grasped tissues. As the needle carriage advances further, it pushes on the needle assembly until each needle has been pushed beyond the point of contact with the needle carriage. At this point the suture needles are through the grasped tissues and protruding through the upper movable jaw and into the needle catch. Due to a pre-defined curve in the flexible inner ribbon, the penetrating tip remains extended from the distal end of each needle&#39;s curved outer sleeve. 
     At this point, any pull force being applied by the grasper on the grasped tissues is relaxed. Once the tissue is in a relaxed state, the jaws of the grasper are then opened. The handle lever is unlocked from the locking mechanism and returns to an open position due to the pull force exerted on it by means of a return spring. As the return spring pulls on the lever, it pivots about a pin. As handle lever pivots, it pulls on the jaw cable coupled to the handle lever by means of a pin. This advances the jaw cable towards the distal end of the barrel. As the jaw cable advances, it pushes on a linkage which then pushes on the movable upper jaw, causing the upper jaw to pivot about a pin. This pivoting motion causes the moveable jaw to open and separate away from the stationary jaw. As the movable upper jaw begins to open, the suture needles for the most part remain stationary due to resistance caused by their contact with the tissues through which they have been driven. At a point just beyond the distal end of the suture needle&#39;s curved outer sleeve, the needle catch on the upper jaw will trap the suture needles at a point between the curved outer sleeve and the penetrating tip, grasping the flexible inner ribbon and securing the needles by interference with the shoulder created between the inner ribbon and the penetrating tip. 
     As the upper jaw slips past the needle&#39;s outer sleeve, the small slit in the needle catch closes down around the needle&#39;s ribbon. The slit is large enough so as not to restrict the movement of the ribbon, but is too small to allow the penetrating tip to pass back through. This is because the needle catch on the upper jaw can only be deflected in an outward direction, away from the outer surface of the upper jaw. Since the distal end of the suture needles are trapped in the needle catch on the upper jaw, they are pulled through the tissues as the upper jaw is opened further. 
     When the jaws of the grasper are fully extended, the suture needles are nearly pulled through the tissue. To complete the pullout of the suture needles, it is necessary to pull on the grasper, and begin to remove it from the repair site. Once the suture needles are through the tissue, they can be secured by closing down the jaws of the grasper. After closing the grasper jaws, the instrument can be retracted back through the portal via the trocar cannula. 
     As the instrument is removed from the suture site, the free ends of the suture are retrieved as well. This causes the suture to pass through the tissues at the puncture sites. As the suture is pulled through, the loop end of the suture is pulled snug against the underside of the tissues to form what is referred to as a mattress stitch. This process may be repeated as necessary, depending on the number of sutures required for the particular procedure being undertaken. 
     The instrument may be reloaded with new suture needles by removing an end cap covering the distal end of the lower stationary jaw. After the end cap is removed, the needle carriage may be advanced beyond the distal end of the lower jaw to be reloaded. To advance the needle carriage in this manner simply requires advancing the handle trigger towards the distal end of the grasper. Once new suture needles are reloaded, end cap may be replaced. The excess suture loop that will form the next stitch passes through the lower stationary jaw through a small notch. This extra length of suture is left outside the body as the grasper is inserted back through the portal to the repair site as previously described. 
     Another embodiment of the grasper/suturing device modifies the needle and suture interface. Instead of the needle carrying the suture by an attachment point at the distal end of the needle, this embodiment releasably attaches the suture to the needle at nearly the proximal end. The major elements of the above described instrument remain the same; i.e. the grasper function with a lower fixed jaw and an upper moveable jaw, and a needle carriage coupled to a trigger for actuation of the stitching function. 
     However, in this second embodiment, the needles are non-releasably attached to the needle carriage; that is to say that they are permanently attached to the carriage. The suture, which is of a braided configuration that is known in the art and has a hollow core, is configured to have a ferrule attached to its ends. This ferrule is constructed such that the hollow braided suture is crimped or otherwise mechanically or adhesively attached to the ferrule. The ferrule includes an interior lumen which is dimensioned such that it is able to be slidably disposed over the end of the needles which are attached to the needle carriage. The needles are configured to have a step, preferably a radiused step, that functions as a stop for the ferrule over which the interior lumen may not pass. 
     Both ends of the suture are loaded onto individual needles, with the excess suture between the ends contained within the bounds of the device. Functionally, as the aforementioned driver trigger is pulled by the surgeon, the needles are disposed to exit from the window in the stationary lower jaw and to transit a curved path through the grasped tissues until reaching a suture catch disposed upon the upper surface of the moveable upper jaw. The needles, carrying the ferrule and attached suture, pass through the suture catch. Since the ferrule is slidably disposed upon the needle, as the trigger is released, the needle carriage withdraws and the needles attached to the carriage are withdrawn through the tissue, leaving the ferrule and attached suture deposited within the suture catch. 
     As described previously, the tension on the grasper is released, and the instrument is withdrawn from the operative trocar, trailing the suture behind, and creating a mattress stitch in the grasped tissues. 
     Now it may be seen by those skilled in the art, the combination of grasping tissues to be sutured and precisely placing a mattress stitch in the grasped tissues while working through a trocar port effects a significant advance in the art. It is therefore an object of the present invention to provide an endoscopic instrument adapted for the grasping of tissues and creating a mattress stitch within those tissues. 
     It is a further object to provide an instrument that allows for the reloading of additional sutures and suture needles for placement of subsequent stitches. 
     The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a torn rotator cuff; 
     FIGS. 2A through 2E are schematic plan views illustrating one embodiment of the invention, and a method, in sequence, for using same; 
     FIG. 3 is a detail perspective view of the jaws of the grasper portion of the present invention; 
     FIG. 4 is a detail perspective view, in isolation, of the underside of the needle guide portion of the present invention; 
     FIG. 5 is a detail perspective view, similar to FIG. 3, of the jaws of the grasper portion of the present invention, with the needle guide removed for clarity; 
     FIGS. 6A through 6D are sequential cross-sectional views illustrating certain steps of an inventive method for deploying suture needles through grasped tissue, using an embodiment of the apparatus of the present invention; 
     FIG. 7 is a perspective view of the internal needle ribbon of the present invention; 
     FIG. 8 is a side, partial cross-sectional view of the jaws of the apparatus of the present invention, clamping down on a portion of a patient&#39;s rotator cuff, 
     FIG. 9 is a side, partial cross-sectional view of the handle of the present invention; 
     FIGS. 10A through 10C are sequential diagrammatic views, in cross-section, illustrating certain steps of an inventive method for capturing suture needles in the movable upper jaw of the inventive apparatus; 
     FIG. 11 is an enlarged perspective view of the jaws of the present invention, wherein suturing material has been grasped therein; 
     FIG. 12 is a schematic perspective view illustrating a mattress stitch which remains in a portion of the rotator cuff of a patient after a suturing procedure has been completed in accordance with the principles of the present invention; 
     FIG. 13 is an enlarged perspective view of the jaws of the present invention, illustrating the reloading of the suture needles; 
     FIG. 14 is a detail perspective view of the interior of the distal end of an alternate embodiment of the suturing device of the invention; 
     FIGS. 15A through 15C are detail cross-sectional views, in sequence, illustrating constructional details and a method for using the alternate embodiment shown in FIG. 14; 
     FIG. 16 is an enlarged detail view, in cross-section, of the tip of the needle illustrated in FIGS. 14 through 15C; and 
     FIG. 17 is a detail perspective view of the inventive embodiment shown in FIGS.  14 - 16 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a method and apparatus for the arthroscopic repair of torn tissue and bone at a surgical repair site using a device, which is a combination tissue grasper and suture placement device. Although the present invention is described primarily in conjunction with the repair of a torn rotator cuff, the apparatus and method could also be used in arthroscopic repair at other sites, such as the knee, elbow, or hip, for example, as well as in conjunction with other surgical techniques. 
     Referring now to FIG. 1, there is shown representative shoulder musculature  1 , including a supraspinatus muscle  2 , a deltoid muscle  4 , a biceps tendon  6 , a torn rotator cuff  8 , and a humeral head  10 . The humeral head  10  is not normally visible, as it is typically covered by the rotator cuff. However, in the illustration, the torn rotator cuff  8  has pulled away from the head  10  of the humerus, exposing it to view. 
     Referring now particularly to FIGS. 2A through 2E, there is illustrated the general structure and function of an embodiment constructed and operated in accordance with the principles of the present invention. A trocar port  12  has been inserted into the shoulder joint, providing a conduit through which a grasper/stitcher  14  may be passed. The grasper/stitcher  14  is provided with pivotable jaws  16  for grasping the torn rotator cuff  8 . The jaws  16  are disposed at a distal end  17  of a hollow barrel  18 . A handpiece  20  is disposed at a proximal end  21  of the hollow barrel  18 , and is adapted to open and close the jaws  16 . In the present preferred embodiment, the handpiece  20  comprises a handle grip  22  and a handle lever  23 , which pivots about a pivot pin. In a manner to be fully described below, the handle lever  23  is suitably connected to the jaws  16  to actuate the jaws  16  between an open and a closed position, depending upon the position of the handle lever  23 . A spring  25  biases the pivotal handle portion to an extended position, as shown in FIG. 2B, wherein the jaws are disposed in an open configuration. Of course, the actuating mechanism which is illustrated for moving the jaws  16  between their open and closed positions, though presently preferred, is only exemplary. Many other types of similar actuating mechanisms are known to those skilled in the art, and any of those would be suitable for the present application. 
     In FIG. 2A, the grasper/stitcher  14  is shown with the jaws  16  closed, trailing a suture  26 , ready to be placed into the shoulder joint through the trocar port  12 . To maintain the jaws  16  in their closed position, the operator holds the two handpiece portions  22  and  23  together, against the biasing force of spring  25 , using a squeezing action. 
     FIG. 2B illustrates the grasper/stitcher  14  having been inserted through the trocar port  12  into the shoulder joint, and the jaws  16  having been opened by releasing the handle lever  23  of the handpiece  20 , so that the handle lever  23  becomes biased away from the handle grip  22 , thereby actuating the jaws  16  to an open position. The jaws  16  are oriented such that the torn rotator cuff  8  is situated between the jaws  16 . 
     As shown in FIG. 2C, the hand piece  20  is again actuated to pivot and close the jaws  16 , to thereby grasp the tissues of the torn rotator cuff  8 . Referring now to FIG. 2D, it is seen that needles  27  have been drawn through the tissues of the tom rotator cuff  8  by rearward movement of a trigger  28 . The needles  27  are captured by the jaws  16 , and, as the grasper/stitcher  14  is withdrawn proximally from the operative site, the suture  26  is drawn along with the grasper/stitcher  14  and through the tissues of the torn rotator cuff  8 , forming a mattress stitch in the tom tendon  8  (FIG.  2 E). 
     Referring now to FIG. 3, the construction and operation of the grasper/stitcher  14  will be more particularly discussed. The jaws  16 , disposed at the distal end  17  of the hollow barrel  18 , include a stationary lower jaw  29  and a moveable upper jaw  30 . Both jaws  16  include teeth  31  which are configured to atraumatically grip tissue such as the torn rotator cuff  8  shown in FIGS.  1  and  2 A- 2 E. Referring now to both FIGS. 3 and 4, it may be seen that the stationary lower jaw  29  is comprised of several elements, including a jaw plate  32  which includes the teeth  31  and needle guides or channels  33   a,b  which are best seen in FIG.  4 . The needle guides  33   a,b  are disposed on the bottom edge of an enclosed aperture  34 . The enclosed aperture  34  allows passage of suture needles  27   a,b  therethrough. The needle guides  33  provide a track for the suture needles  27  to ride in, thereby correctly orienting the needles. The stationary lower jaw  29  also includes a removable end cap  36  which will be discussed in further detail below. 
     Referring now to FIG. 5, the jaw plate  32  has been removed in order to show a needle carriage  38 , which is slidably disposed within the stationary lower jaw  29  formed at the distal end of the hollow tube  18 . The needle carriage  38  has capture tabs  40   a,b,c,d  located on its distal end. The capture tabs  40  are used to couple the needle carriage  38  with the suture needles  34 . The proximal end of the needle carriage  38  is affixed to a slide cable  42   a,b . Slide cable  42  is forked on its distal end to allow it to pass on either side of a linkage  44 , which is used to activate the movable upper jaw  30 . Referring to FIG. 6A it may be understood that for clarity only one suture needle  27  is shown, but that any description of the single needle is understood to apply to both suture needles  27   a,b . Accordingly, there may be seen a suture needle  27  which includes a curved outer sleeve  46  tapered from a larger diameter at its proximal end to a smaller diameter at its distal end. A ribbon  48  is sidably and coaxially disposed within the curved outer sleeve  46 . Referring to FIG. 7, it may be seen that the flexible inner ribbon  48  is circular at its proximal end  50 , and transitions into a rectangular shape at its distal end  52 . The flattened ribbon shape disposes the flexible inner ribbon  48  to bend in a pre-defined orientation suitable for this application. Referring back now to FIGS. 6A-6D, the distal end  52  of the flexible inner ribbon  48  is permanently attached to a penetrating tip  54 . The penetrating tip  54  is tapered to a sharp point  56  at its distal end, to facilitate penetration into tissue. As it may be appreciated by those skilled in the art, there are many different designs and configurations of needles adapted for passing through tissue, including both sharp and blunt tips. It is to be understood that any of these tip designs may be accommodated in the present invention. A needle stop  58  is affixed to the flexible inner ribbon  48  at a predetermined distance from the proximal end of the curved outer sleeve  46 . A needle shoulder  60  is affixed to the flexible inner ribbon  48  at a predetermined distance from the proximal end of the needle stop  58 . A length of suture  26 , which may be constructed from any material known in the art as suture material, for example braided polyester, is permanently attached to the proximal end of the needle shoulder  60 . 
     Now with reference back to FIG. 5, it may be seen that the movable upper jaw  30  includes a needle catch  64  attached to its outer surface. The needle catch  64  further comprises elongated apertures  66   a,b , which are formed by a tab  68 . When the jaws  16  are in a position of grasping tissue as shown in FIG. 8, the movable upper jaw  30  and the stationary lower jaw  29  are aligned to allow for the suture needles  34  to pass through the apertures  66   a,b  in the needle catch  64 . How the needle catch  64  captures the suture needles  27  will be explained in more detail below. 
     As illustrated in FIG. 8, the linkage  44  includes a pin  70 , a link  72 , a pin  74 , a jaw cable  76 , and a second pin  78 . The movable upper jaw  30  is rotatably attached to the hollow barrel  18  by means of the pin  70 . The proximal end of the movable upper jaw  30  is rotatably attached to the distal end of the link  72  using the pin  74 . The proximal end of the link  72  is then rotatably attached to the jaw cable  76  using the pin  78 . The movable upper jaw  30  pivots about the pin  70  when activated by the jaw cable  76 . 
     The actuation mechanism that causes the jaw cable  76  to move will now be described in greater detail. As shown particularly in FIG. 9, the jaw cable  76  passes through the proximal end of hollow barrel  18  to the handpiece  20 . The proximal end of the jaw cable  76  is attached to the handle lever  23  by means of a pin  82  which is slidably disposed within a slot  84  at the top of the handle lever  23 . The handpiece  20  includes the handle lever  23 , the handle grip  22  and a pivot pin  88 . The handle lever  23  is pivotally attached to the handle grip  22  using the pivot pin  88 . The extension spring  25  is attached to the handle lever  23  by way of a pin  92 . The other end of the extension spring  25  is attached to the handle grip  22  by way of a pin  94 . The handle lever  23  is normally in an open position, due to force pulling on it by way of the extension spring  25 . This means that the movable upper jaw  30 , located at the distal end of the device, is in a normally open position due to the spring force. 
     As shown in FIG. 9, the slide cable  42 , previously described in reference to FIG. 5, passes through the proximal end of the hollow barrel  18  to the handle  20 . The proximal end of the slide cable  42  is attached to the trigger  28 , using a pin  98 . An outer sleeve  100  is slidably and co-axially placed over the slide cable  42 . A compression spring  102  is slidably and co-axially placed over the slide cable  42  and abuts the outer sleeve  100  on one end, and a spring land  104  on the other end. The compression spring  102  provides a return force to the trigger  28  and consequently to the needle carriage  38  after deployment of suture needles  34 . 
     In a preferred method of the present invention the grasper/stitcher  14  is inserted through a portal in the shoulder, as shown in FIG.  2 B. The portal is opened by first making an incision in the skin then inserting the trocar port  12  through the incision to the repair site. The distal end of the hollow barrel  18  is inserted through the cannula until the jaws  16  reach the tom rotator cuff tissue  8 . In operation, the distal end of the grasper is positioned at the repair site against the tissue to be grasped. Moveable jaw  30  is advanced toward the stationary jaw  29  by squeezing handle lever  23 . As lever  23  moves inwardly by pivoting about pivot pin  88 , the jaw cable  76  is drawn rearwardly, proximal of the handpiece  20 . When the jaw cable  76  is retracted rearwardly, the movable jaw  30  pivots toward the stationary jaw  29  to close the jaws. Once the appropriate section of tissue is isolated and grasped by jaws  16 , the lever  23  may be locked in its closed position, using a latch mechanism (not shown). 
     Once the surgeon is satisfied with the placement of the grasper  14 , the surgeon can then deploy the suture needles to create a mattress stitch in the torn rotator cuff  8 . In operation, the suture needles  27  are advanced through the rotator cuff by pulling on the trigger  28 . This action draws the slide cable  42  rearwardly towards the proximal end of the grasper. As the slide cable  42  is pulled rearwardly, it is pulled against the force of return spring  102 . As the slide cable  42  moves rearwardly, it pulls the needle carriage  38  and suture needles  27  proximal to the needle guide aperture  33  (FIG.  6 A). The suture needles  27 , as they clear the distal edge of the aperture  34 , begin to penetrate through the underside of the rotator cuff  8  and advance upwardly towards the movable jaw  30 . 
     Referring now again to FIGS. 6A-6D, the needles are illustrated at various stages of advancement through the rotator cuff In FIG. 6A, the proximal end of the suture needles  27  are fully engaged in the locking tabs of the needle carriage  38 . As the suture needles  27  near the end of the ejection stroke, the distal end of the needles  27  pass through the upper movable jaw  30  and the needle catch  64 . As the needles pass through the upper jaw  30 , they begin to separate from the needle carriage  38  (FIG.  6 B). 
     As the proximal end of the needle&#39;s curved outer sleeve  46  separates from the first tab on the needle carriage  38 , there is no further force pushing on it to force it through the rotator cuff  8 . The force now pushing on the suture needle  27  is concentrated on the needle stop  58 . As the carriage  38  is advanced further, the needle&#39;s curved outer sleeve  46  remains stationary due to the resistance caused by contact with the tissue of the rotator cuff  8 . However, the needle ribbon  48  is free to advance further. As shown in FIG. 6C, the gap between the needle&#39;s curved outer sleeve  46  and the needle stop  58  begins to close until there is no gap at all. At this point the penetrating tip  54  has extended beyond the distal end of the needle&#39;s curved outer sleeve  46 . Once the gap is closed between the needle stop  58  and the outer sleeve  46 , the needle will again continue to advance as one unit through the rotator cuff  8 . As the needle carriage  38  advances further, it pushes on the suture needle  27  until the needle has been pushed beyond the point of contact with the needle carriage  38  (FIG.  6 D). At this point the suture needles  27  extend through the torn rotator cuff  8  and protruding through the upper movable jaw  30  and needle catch  64 . Due to a pre-defined curve in the needle&#39;s ribbon  48 , the penetrating tip  54  remains extended from the distal end of the needle&#39;s curved outer sleeve  46 . 
     At this point, any pull force being applied by the grasper  14  on the rotator cuff  8  is relaxed. Once the rotator cuff is in a relaxed state, the jaws of the grasper  14  are then opened. The handle lever  23  is unlocked from the locking mechanism (not shown) and returns to an open position due to the pull force exerted on it by means of the return spring  25 . As the return spring  25  pulls on the lever  23 , the handle lever  23  pivots about the pin  88 . As the handle lever  23  opens, it pulls on the jaw cable  76  by means of the pin. This advances the jaw cable  76  towards the distal end of the barrel  18 . As the jaw cable  76  advances, it pushes on the linkage segment  44 , which then pushes on the movable upper jaw  30 , causing the upper jaw  30  to pivot about the pin  70  to open and separate away from the stationary jaw  29  (FIG.  8 ). 
     As shown in FIG. 10 a , as the movable upper jaw  30  begins to open, the suture needles  27  for the most part remain stationary due to resistance caused by their contact with the tissue of the rotator cuff  8 . As the upper jaw  30  is opened, it slips pass the suture needles  27 . At a point just beyond the distal end of the suture needle&#39;s curved outer sleeve  46 , the needle catch  64  on the upper jaw  30  trap the suture needles  27  at a point between the curved outer sleeve  46  and the penetrating tip  54 . 
     Now, with reference to FIG. 10 b , it is seen that the upper jaw  30  slips pass the needle&#39;s outer sleeve  46 . The aperture or slit  66  in the needle catch  64  is allowed to close down around the needle&#39;s ribbon  48 . The slit  66  is large enough that it does not restrict the movement of ribbon  48 , but is sufficiently small so that it does not allow the penetrating tip  54  to pass back through. This is because the needle catch  64  on the upper jaw  30  can only be deflected in an outward direction, away from the outer surface of the upper jaw  30 . Thus, now that the distal end of the suture needles  27  are trapped in the needle catch  64  on the upper jaw  30 , they are pulled through the rotator cuff as the upper jaw  30  is opened further. 
     As shown in FIG. 10 c , when the jaws  16  of the grasper  14  are fully extended, the suture needles  27  are nearly pulled through the rotator cuff  8 . To complete the pull out of the suture needles  27 , it is necessary to pull on the grasper  14 , and to begin to remove it from the repair site. 
     Now with reference particularly to FIG. 11, once the suture needles  27  are extended through the rotator cuff  8 , they can be secured by closing down the jaws  16  of the grasper  14 . Then, the graspers can be retracted back through the portal via the trocar cannula  12  (FIGS.  2 D and  2 E). 
     As shown in FIG. 12, the next step in the preferred method is to pull on the free ends  105  of the suture  26 . This causes the suture to pass through the rotator cuff  8  at puncture sites  106   a  and  106   b . As the suture is pulled through, the loop end  107  of the suture is pulled snug against the underside of the rotator cuff  8  to form what is referred to as a mattress stitch. This process is repeated as necessary, depending on the number of bone anchors required to repair the rotator cuff for a given surgical procedure. 
     To reload the inventive instrument with new suture needles  27 , the end cap  36  is pulled off to provide necessary access, as shown in FIG.  13 . After the end cap  36  is removed, the needle carriage  38  can be advanced beyond the distal end of the barrel  18  to be reloaded. To advance the needle carriage  38  in this manner simply requires advancing the handle trigger  28  towards the distal end of the grasper  14 . Once new suture needles are reloaded, the end cap  36  can be replaced. The remaining suture to form the next stitch passes through the lower stationary jaw  29  through a small notch abutting the end cap (not shown). This extra length of suture may be left outside the body as the grasper  14  is inserted back through the portal  12  to the operative site. 
     A second, modified embodiment of a suturing instrument constructed in accordance with the principles of the present invention is illustrated in FIGS. 14-17. With respect to this embodiment, it is to be understood that the proximal portion of the device is substantially the same as that illustrated with respect to the earlier embodiment, and is therefore not shown. Thus, in FIG. 14, there is seen a distal end  108  of the inventive suturing device, which includes a moveable upper jaw  109 , a stationary lower jaw  110 , and a body  112 . The moveable upper jaw  108  is pivotally attached to the body  112  via a pin  114 , and includes a ferrule catch  116  which further includes slits  118   a,b . The ferrule catch  116  is preferably constructed of a high temper spring steel suited for tissue contact. By way of example only, ANSI  301  spring temper steel is suitable for this application. A needle carriage  120  is slidably disposed on the lower stationary jaw  110 . The needle carriage  120  is permanently affixed to slide cables  122   a,b , and moves proximally from a distal position to a proximal position within the lower stationary jaw  110  when urged by the slide cables  122 . The needle carriage  120  includes tabs  124   a,b  to which are coupled needles  126   a,b . The needles  126  may be constructed, as is well known in the art, of  300  or  400  series stainless steel. As shown in FIGS. 15-17, each needle  126  includes a sharpened tip  128 , a bulge  130 , and a body  132 . The bulge  130  may be best seen by referring to FIG. 16, where a suture  134  comprising a hollow inner lumen  136  and a distal end  138  may also be seen. The distal end  138  is encapsulated by a ferrule  140 . The ferrule  140  is further comprised of an outside diameter  142 , an inside diameter  144 , and a shoulder  146 . The distal end  138  of the suture  134  is passed into the ferrule  140  and crimped or otherwise mechanically or adhesively attached to the ferrule  140 . 
     In operation, the body  132  of the needle  126  is threaded into the hollow inner lumen  136  of the suture  134  and through the inside diameter  144  of the ferrule  140 . The bulge  130  interferes with the shoulder  146  of the ferrule, thereby preventing the ferrule  140 , and concomitantly the suture  134 , from sliding further along the body  132 . Referring now to FIGS. 15A-15C, in particular, the function of the combination of the needles  126  and the suture  134  is illustrated. In FIG. 15A, the needles  126  and the ferrule  140  are enclosed by a housing cap  148 . It is to be understood that, for clarity, he tissue that would normally be grasped between the moveable upper jaw  109  and the stationary lower jaw  110  is not shown. It is also to be understood that FIGS. 15A-15C depict a cross-sectional view showing only one of the two needles  126 . Accordingly, and with reference now to FIG. 15B, it may be seen that, as the slide cables  122  are withdrawn as previously described in connection with the prior embodiment, the needle carriage  120  is drawn along a path from the distal to the proximal end of the stationary lower jaw  110 . The needles  126 , being fixedly attached to the needle carriage  120 , are urged to exit the stationary lower jaw  110  and to transit along a curved path described by the pre-configured ben in the needles  126  until penetrating the catch  116  at the slits  118 . The ferrule  140  is forced to traverse the slits  118  by the urging of the bulge  130  on the shoulder  146 . As the tension on the slide cables  122  is released, the needle carriage  120  is permitted to return to its original position by reversing its motion so that it travels distally. As shown in FIG. 15C, the transition of the needle carriage  120  back to its original position functions to cause the needles  126  from the hollow inner lumen  136  of the suture  134  and from the inside diameter  144  of the ferrule  140 , leaving the ferrule  140  trailing the suture  134  to be captured by the ferrule catch  116 . This may be seen most advantageously by reference to FIG.  17 . 
     At this point, with the suture  134  and the ferrules  140  captured, the tissue grasped by the moveable upper jaw  109  may be released, and the instrument withdrawn from the operative site, trailing the suture loop stored within its bounds. The result of the execution of these method steps is the creation of a mattress stitch in the grasped tissues in a manner similar to that described with respect to the embodiment illustrated in FIGS. 2-13. 
     The apparatus and method of the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.