BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a device and methods for delivering partial or full thickness suture into tissues endoscopically. This invention also relates to devices and methods used to minimize the strain and stress on shape memory elements.

2. Description of the Background Art In recent years, much attention has been given to control surgical costs. One of the cost saving approaches is to accelerate the speed of recovery and shorten hospital stays after surgeries. In addition to lowering costs, for the comfort and safety of patients, minimally invasive or endoscopic surgeries are becoming more and more popular. The term "endoscopic"used in this invention encompasses arthroscopic, laparoscopic, hysteroscopic and other procedures. Endoscopy is a surgical procedure which allows surgeons to manipulate instruments to view the surgical sites through small incisions in the bodies of patients.

An endoscopic surgery begins with punching holes through soft tissue such as skin and muscle. After the holes are punched with sharp instruments, hollow cylindrical tubes are inserted through the holes of the soft tissue. These tubes serve as tunnels for the endoscope and surgical instruments reaching into the surgical site.

In order to minimize both the patients'trauma and potential damage to nerves, blood vessels and other tissues, it is clearly desirable to minimize the size and number of holes puncturing on the patients. Take meniscal repair in the knee for example. the current arthroscopic procedure requires one hole for the arthroscope, one hole for a needle to deliver a suture and another hole for a suture-retrieving instrument to complete one suture stitch (Arthroscopic Surgery by L. Johnson, M. D. ; Knee Surgery by F. Fu, MD. et al. ; Traumatic Disorders of the Knee by J. Siliski, MD; and Knee Surgery Current Practice by P. Aichroth, FRCS et al.). A minimum of three holes are made for the arthroscopic repair. In some cases, surgeons also require a distractor, an external fixation device which is screwed in through skin to the bones, separating the femur from the tibia. This expands the knee joint and makes room to manipulate both the suture and the suture-retrieving instrument. Due to the tightness of joint space, often needle or instrument can accidentally scrape and damage the smooth

surface of the joint cartilage, which given time, can potentially lead to osteoarthritis years after the surgery.

Arthroscopic and endoscopic suturing are done with a full-thickness technique, where sutures penetrate all the way through a tissue for each stitch. In the case of meniscal repair, the full-thickness suture repair can potentially cause long term problems, including osteoarthritis, from the constant rubbing of a very smooth joint surface to the exposed suture on the surface of the meniscus. Unless the damaged tissues can be lifted, shifted or somehow separated from crowded adjacent tissues, endoscopic procedures usually cannot be performed due to insufficient space for manipulating sutures and instruments. In these cases and others, conventional open surgery using a curved needle performing a partial-thickness suturing technique, where the suture enters and loops back out without full-thickness penetration, is pursued for the repair.

Some needles (US patent 5,474,565 to Trott, 1995; US patent 5,222,977 to Esser, 1993; US patent 5,330,491 to Walker et. al.) are designed for endoscopic surgical use.

These surgical needles require multiple skin punctures and cumbersome suture manipulation to complete each stitch.

In summary, most current instruments used in endoscopic procedures have one or more of the following drawbacks or restrictions ; (A) Multiple surgical trauma due to multiple body punctures required to accommodate suture manipulation and retrieving instruments.

(B) Risk of damaging nerves, blood vessels, joint cartilage or adjacent tissues with multiple punctures and cumbersome suture manipulation.

(C) Lengthened surgical time.

(D) Restricted by space required around and behind the surgical site.

(E) Limited to full-thickness suture repair.

Another invention, US patent 5,250,055 to Moore et. al., 1993, proposed a tissue- fastening technique onto bone. Moore's invention requires the drilling of two parallel holes in bone. The holes are then fitted with double barrels. A suture is attached to a solid, not hollow, shape memory hook straightened by one barrel. As the straightened hook is pushed out of the barrel, the shape of the hook resumes and carves a tunnel in the trabecular bone reaching the second drilled hole. Another barrel houses suture retrieving tweezers to pull the suture and complete the suture loop inside the bone. The suture is then used to tie down damaged tissues onto bone. This device is not frequently used because of the large holes it makes in the bone and the difficulty of retrieving the suture with the tweezers inside the bone.

Recently, tacks (US patent to Green, 1995; US patent 5,059,206 to Winters, 1991; US patent to Bays et. al., 1990) and staples (US patent 5,374,268 to Sander, 1994; US patent 5,154,189 to Oberlander et. al., 1992) made out of polymers and metals have been used as permanent implants to hold torn tissues in place. Very few of these

devices have the holding strength of sutures. With time, some tacks and staples creep and leave gaps in the supposed closure sites. Some biodegradable tacks and staples do not last long enough for the damaged tissue to heal before disintegrating. Many of these biodegradable implants also have serious biocompatibility problems which cause inflammation and other harmful cellular interactions. For the long lasting polymeric or metal tacks and staples, there is always the nagging potential problem of device migration, which can be devastating, especially migrating into joints or nerves.

SUMMARY OF THE INVENTION In this invention, a suture can be guided, delivered, retrieved and tied through one opening in the skin without additional suture retrieving instrument, for partial-thickness or full-thickness repairs.

The major components of this suturing device comprise of three types of needles. A hollow suture-delivering needle mounts parallel or near parallel to a hollow suture-retrieving needle, with depth of penetration markings on the outsides of the needles visible to an endoscope. The sharp tips of the needles are the distal ends of the needles. A third, smaller gauged hollow connection needle, made out of material such as nickel titanium, high carbon steel, polymer or other alloy, is bent with its shape retained in a semi-circular hook at and near the sharp tip, distal end, of the connection needle. The proximal ends of these needles are not sharpened and are open.

In its retracted position, the connection needle with the hook is housed and partially straightened inside the suture delivering needle. To minimize the strain and stress exerted on the hook by the inside cannula of the suture delivering needle, a strain and stress relief window can be opened to the outside of the suture delivering needle, where the back of the hook is partially protruded from inside and exposed at or near the surface of the suture delivering needle. On the opposite side of the strain and stress relief window, a guiding slot with a tapering trough is also made at the distal opening of the suture delivering needle allowing the hook of the connection needle to slide in and out of the distal opening of the suture delivering needle.

To deploy the connection needle, an operating lever attaching to the proximal portion of connection needle pushes the hook out through the guiding slot of the suture delivering needle. In a deployed position, the sharp hook extends out of the delivering needle and follows a semi-circular path into a receiving slot at the distal opening of the adjacent suture receiving needle.

To initiate an endoscopic surgical procedure, a skin incision is made. The repair site is examined with an endoscope, and the ideal placement of the suture is determined. After examination, the endoscope is withdrawn from skin then inserted into an endoscopic equipment inlet and protruded through an endoscopic outlet of the suture device. Through the

incision of the skin, the suture device is guided by the view transmitted by the endoscope to the surgical site. The sharp suture delivering and suture receiving needles are pierced into the previously determined suture placement site. The depth of penetration of both needles are indicated by the markings on the needles, visible to the endoscope. When the ideal depth is reached, the sharp hook of the connection needle, which is initially set in a retracted position, is deployed from the suture delivering needle into the receiving slot of the suture receiving needle. Since the distal end of the connection needle is sharp, it can pierce the tissue as it is deployed enroute to the receiving slot of the suture receiving needle, forming a partial- thickness suturing. On the other hand, if the tissue is initially pierced through by both the suture delivering and suture receiving needles, the sharp hook of the connection needle is deployed outside the tissue, forming a full-thickness suturing.

For ease of suture threading, the endoscope can now be withdrawn from the device. To aid in the suture threading process, a funnel is connected to a proximal beveled cannula of the connection needle. For surgical operations in which braided sutures are preferred, a long piece of flexible filament is fused and attached, tip to tip, with the braided suture : mono- filament sutures on the other hand can possibly be threaded directly without the aid of the flexible filament. For repairs which required high tensile strength, instead of suture, a wire or cable can be used. Using pushing and twisting motions, the filament, monofilament suture or wire is advanced through the suture threading funnel into the proximal beveled cannula of the connection needle, out of the distal opening of the connection needle, into the distal opening of the suture-receiving needle, then out its proximal opening. The suture is now in and around the repair site, with both ends of the suture outside the body of the patient.

For a small hook, it can be difficult to push the suture or filament in and around the inner cannula of the small hook in a small semi-circular shape. Instead of following the path of a small semi-circle, while the hook is partially straightened inside the suture delivering needle, the suture can easily be advanced until the tip of the suture or filament is pushed near the distal opening of the straightened hook, prior to the deployment of the connection needle.

As the partially straightened hook is deployed resuming the shape of the hook with the suture inside, the tip section of the suture or filament is already around the small semi-circle, the most difficult segment of the suture passing route. The rest of the suture can then be easily advanced through cannula of the suture receiving needle.

Before suture tying, the connection needle is retracted back into the suture delivering needle. The filament attaching to the braided suture is cut off. The suture device is withdrawn, leaving the suture in and around the surgical site.

As mentioned earlier, either partial or full-thickness sutures can be placed depending on whether the connection needle was deployed within or outside the surgical tissue. If the deployment was within the tissue, then it will be a partial-thickness suture repair. On the other hand, if the deployment was outside the tissue, then it will be a full-thickness suture

repair. In some cases, it is also possible to have a combination of both partial and full- thickness suture repairs.

Slip knots are then tied and delivered with a knot pusher to the surface of the surgical site. Excess suture is cut off with endoscopic scissors to finish a stitch of suture repair. The process is repeated for multiple stitches to fasten tissues endoscopically, with partial-thickness or full-thickness suture repairs selected on a stitch by stitch basis.

Furthermore, the utilization of a connection needle to bridge the suture delivering and the suture receiving needles in this invention, can also be used to pass suture into bone. For example, two holes can be pre-drilled into cortical bone prior to inserting the suture delivering and receiving needles. Beneath the cortical bone, trabecular bone, which is much softer and porous, can be pierced by the sharp connection needle.

This invention has many advantages over tacks and staples. Sutures are being used and have been proven and well accepted as permanent fastening devices in open and endoscopic surgeries for a long time without significant adverse effects. On the other hand, use of tacks and staples as permanent implants always bear concerns over their biocompatibilities, rates of resorption, creeping, and implant migrations. In this invention, well-placed sutures are the only permanent implant materials, and using proven knot tying techniques mastered by all well trained endoscopic surgeons ensure a tight and trouble-free partial-thickness or full- thickness endoscopic suture repair.

In summary, this invention has the following possible benefits over most current instruments and devices used in endoscopic repair: (A) Single body puncture needed to place, manipulate and retrieve a suture.

(B) Minimal risk of damaging nerves, blood vessels, joint cartilage or adjacent tissues with single puncture and minimal suture manipulation.

(C) Shortened surgical time.

(D) Minimal space required around and behind the surgical site.

(E) Capable in accomplishing both full-thickness as well as partial-thickness suture repair.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. lA depicts a cut away view of a suture device with the connection needle 7 in a retracted position with a suture threading funnel 18, an operating lever 17, an endoscopic inlet 15 and a suture outlet 20.

FIG. I B depicts a suture delivering needle 1 on the right and a suture receiving needle 10 on the left with a retracted connection needle 7 mostly hidden inside the cannula of suture delivering needle 1. Figure I A and 1B also show a relief window 5 on the side of the suture delivering needle 1, allowing the connection needle 7 to rest in the relief window 5 to minimize strain on and to assist deployment direction of the connection needle 7.

FIG. 1C depicts the same needles as FIG. 1B, but the connection needle 7 is in a deployed position bridging the gap between suture delivering needle 1 and suture receiving needle 10 with the connection needle 7 extending well into a receiving slot 12.

FIG. 1 D depicts a suture delivering needle 1 on the right and a suture receiving needle 10 on the left with a retracted connection needle 7 mostly hidden inside the cannula of suture delivering needle 1; no relief window 5 is carved on the suture delivering needle 1.

FIG. IE depicts the same needles as FIG. ID, but the connection needle 7 is in a deployed position bridging the gap between suture delivering needle 1 and suture receiving needle 10 with the connection needle 7 extending well into a receiving slot 12; no relief window 5 is carved on the suture delivering needle I.

FIG. 2 depicts side and back views of the suture device with the connection needle 7 in a retracted position, hidden inside the suture delivering needle 1 on the right.

FIG. 3 depicts side and front views of the suture device with the connection needle 7 retracted as indicated in FIG. 2. Depth of penetration markings 13 on both the suture delivering needle I and suture receiving needle 10 are visible by an arthroscope (not shown) fitted into an endoscopic outlet 16 between the needles.

FIG. 4 depicts the same view as FIG. 2 with a deployed connection needle 7 into the adjacent suture receiving needle 10.

FIG. SA depicts an arthroscope 27 guiding the penetration of the suture device through a small skin opening 23 into a torn meniscus 24 for a partial-thickness suture repair.

FIG. 5B depicts an enlarged and longitudinal mid-section of the needles in the torn meniscus, with the connection needle 7 in a retracted position.

FIG. 6A depicts the deployment of the connection needle 7 in a torn meniscus 24. (The arthroscope removal following this deployment is not shown.) FIG. 6B depicts an enlarged and longitudinal mid-section of the needles in the torn meniscus, with the connection needle 7 in a deployed position bridging the gap between suture delivering distal opening 2 and suture receiving distal opening 11.

FIG. 7A depicts a suture threading process into the device through an aperture or funnel 18, into a proximal beveled cannula 9 (see FIG. lA) of connection needle, using the pushing and twisting motion on a filament 22 connecting to a soft suture 21.

FIG. 7B depicts an enlarged and longitudinal mid-section of the needles in the torn meniscus, with the filament 22 attaching to the suture 21 passing through the connection needle 7 from the suture delivering needle 1 into the suture receiving distal opening 11.

FIG. 8A depicts the cutting of the filament 22, after leading the suture 21 in, through and around the meniscal tear 24, then coming out of a suture outlet 20 of the device.

FIG. 8B depicts an enlarged and longitudinal mid-section of the needles with the suture 21 looped around the meniscal tear 24, from the suture delivering needle I to the suture receiving needle 10 bridged by the connection needle 7.

FIG. 9A depicts a process of retracting the connection needle 7, leaving only the suture 21 joining the suture delivering distal opening 2 and suture receiving distal opening 11.

FIG. 9B depicts an enlarged and longitudinal mid-section of the needles with the retracted connection needle 7; between the suture delivering distal opening 2 and suture receiving distal opening 11, only the suture 21 loops around the meniscal tear 24.

FIG. 10A depicts a process of withdrawing the suture device with the suture 21 remaining at the repair site.

FIG. I OB depicts an enlarged and longitudinal mid-section of the withdrawn needles with the suture 21 looping around the repair site.

FIG. II A depicts the partial-thickness placement of the suture 21 in the meniscal tear 24 with the suture device withdrawn.

FIG.! ! B depicts an enlarged suture 21 in and around the meniscal tear 24.

FIG. 12 depicts a suture tying process using a knot pusher 26 tying a slip knot to close and hold the torn portion of meniscus 24.

FIG. 13 depicts a partial-thickness suture repair of a meniscal tear 24. Excess suture 21 is cut off with endoscopic scissors 6.

FIG. 14 depicts an arthroscopically guided full-thickness suture repair of a partially torn anterior cruciate ligament 25, with the connection needle 7 deployed outside the torn anterior cruciate ligament 25.

FIG. 15 depicts a full-thickness suture repair after tying knot and cutting excess suture, of the torn anterior cruciate ligament 25.

FIG. 16 depicts a relief window 5, a guiding slot 3 and a trough 4. In combination, these devices provide a track-like path to ensure the connection needle 7 (not shown) extends properly from the suture delivery needle I to the suture receiving needle 10 (also not shown).

FIG. 17A depicts a preferred angle of tip sharpening on a connection needle distal opening 8 indicated in a deployed position and a preferred angle of opening of relief window 5.

FIG. 17B depicts a distal tip of the connection needle resting on the trough 4 slightly outside the inner cannula of suture delivering needle 1.

FIG. 18A depicts a preferred lateral-cut angle of a receiving slot 12 on the suture receiving needle 10.

FIG. 18B depicts a right-angle lateral-cut of the receiving slot 12 on the suture receiving needle 10.

FIG. 18C depicts an acute-angle lateral-cut of the receiving slot 12 on the suture receiving needle 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT The word"needle"is used to describe a needle with tissue puncturing capability, as well as a lumen or cannula, in the center allowing sutures to pass through. Stainless steel is the preferred material for the suture delivering needle 1 and the suture receiving needle 10. The connection needle 7 on the other hand, is best made out of nickel-titanium alloy or other shape memory alloys sharpened from the inner circumference of the bend, as depicted in FIG. 17A.

The outer portion of the device includes the handle 19, body 14 and the connection needle operating lever 17. The preferred materials to use for these are metal, polymer or both, which tolerate multi-sterilization cycles of autoclave, gamma-irradiation, electron-beam irradiation, ethylene oxide or combination of sterilization techniques.

Sutures 21 include any surgical suture, synthetic, natural, bioabsorbable, non- absorbable, metallic, braided, monofilament or combination. It also includes suture 21 incorporated with materials, such as blood clot residues, cells, growth factors, tissue healing factors, nutrients, mineras. antibiotics, adhesives, drugs, delivery component, lubricants or other substance.

The preferred material for the filament 22 is a flexible and pushable monofilament polymer or metallic wire tolerant to sterilization methods, such as autoclave, gamma- irradiation, electron-beam irradiation, ethylene oxide or combination. The preferred connection between the filament 22 and the suture 21 is tip to tip fused by heat, light, ultrasound, adhesives, mechanical holding or combination. The outer diameters of both filament 22 and suture 21 are preferred to be smaller than the cannula diameter of the connection needle 7.

Although the relief window 5 is unnecessary and the connection needle 7 can exist within the confines of the suture delivery needle 1 without being deformed, the relief window 5 can provide a directional guidance for the deployment of the connection needle 7. In this invention, directional deployment is crucial and is predetermined specifically for bridging the gap between the suture delivering needle 1 and suture receiving needle 10.

As indicated in FIGs 16,17A and 17B, the relief window 5 is fully penetrated or opened from the inside cannula to the outside wall of the suture delivery needle I. Although less effective in relieving the strain and stress and in directing the path of deployment of a connecting needle 7, another design of the relief window 5 can be an elongated indentation carved from the inside of the cannula but not fully opened to the outside wall of the suture delivery needle 1.

The guiding slot 3 and the trough 4, indicated in FIG. 16 is another device in this invention used to reduce the strain and stress of shape memory material, such as the connection needle 7. A trough 4 is carved at the inside cannula of the suture delivery needle 1, tapering distally to the outer edge of the guiding slot 3. The angle of tapering provides a smooth gliding surface for the preferred sharpened angle of the connection needle 7 depicted

in FIGs. 17A and 17B. The tapering trough 4 of the guiding slot 3 provides four major benefits (1) to minimize grinding and dulling of the sharpened tip of the connection needle 7, (2) to allow the sharpened tip of the connection needle 7 in retracted position to house outside the cannula of the suture delivery needle 1 thereby further minimizing the strain and stress on the connection needle 7, (3) to ease the forces required to deploy and retract the connection needle 7, and (4) to orient the direction of deployment of the connection needle 7.

To ensure the proper insertion of the connection needle 7 into the receiving slot 12, the preferred angle of longitudinal opening of the receiving slot 12 is depicted in FIGs. 18A, 18B and 18C. During the initial tissue piercing with the suture receiving needle 10 along with suture delivery needle 1, the lateral-cut angle of the receiving slot 12 depicted in FIG. 18A is preferred over the angles depicted in FIGs. 18B and 18C to avoid tissue snagging, trapping and possible closure of the receiving slot 12.

In case closure of the suture receiving needle distal opening) 1 results from tissue entrapment during initial piercing, a wire can be inserted into the suture outlet 20 and passed down the cannula of the suture receiving needle 10 to clear the closure. Similarly, a wire can also be used to clear a closure of the connection needle 7 prior passing the filament 22 and suture 21.

During surgeries, the suture delivery needle I and the suture receiving needle 10 can mistakenly be twisted by surgeons, causing the connection needle 7 to miss entering into the receiving slot 12. To minimize the twisting, a body 14 is used to fix both needles stationary and to shorten the twistable length of the exposed suture delivery needle 1 and suture receiving needle 10.

Deployment and retraction of the connection needle 7 is controlled by and attached to the operating lever 17, as depicted in FIG. IA. The suture threading process is facilitated by an enlarged aperture or a funnel 18 at the proximal end of the operating lever 17 leading into the proximal beveled cannula 9 of connection needle, as depicted in FIG. IA.

Furthermore, the utilization of a connection needle 7 to bridge the suture delivering needle I and suture receiving needle 10 in this invention can also be used to pass suture 21 into bone. For example, two holes can be pre-drilled in cortical bone prior to inserting the suture delivering needle 1 and suture receiving needle 10. Beneath the cortical bone, trabecular bone, which is much softer and porous, can easily be pierced by a sharp connection needle 7.

It should be clear to one skilled in the art that the current embodiment, method and surgical sites are not the only use for which the invention may be used. Different materials for the needles, body, handle, lever, suture filament and other components can be used. The use of this invention is also foreseen in other surgical operations to repair or fasten various tissues, such as tendon, ligament, muscle, cartilage, skin, cosmetic lifts, bone, organ, tissue grafting, prosthesis and others. Nothing in the preceeding description should be taken to limit the scope of the present invention. The full scope of the invention is more fully described in the appended claims.