Surgery – Instruments – Suture retaining means
Reexamination Certificate
2000-06-27
2003-09-16
Lewis, Ralph A. (Department: 3732)
Surgery
Instruments
Suture retaining means
C606S215000, C606S092000
Reexamination Certificate
active
06620185
ABSTRACT:
TECHNICAL FIELD
This invention relates to surgical procedures and instruments.
BACKGROUND
Many surgical procedures involve fixing soft tissue to bone, particularly in the area of shoulder surgery, for example rotator cuff repairs and instability repair. Generally, in these procedures, the surgeon forms an incision to access the surgical site and then uses one of the following techniques to reattach the soft tissue.
In one technique, the surgeon drills bone tunnels through which a suture is passed. The suture is tied through the soft tissue, which is then reapproximated back to the bone.
In an alternative technique, the surgeon drills a cavity in the bone and inserts a bone anchor. Typically, the bone anchor is formed of metal, plastic or a resorbable material, and is held in place by wings or barbs that deploy outward, by threads or by radial expansion. The anchor includes an eyelet through which a suture is threaded. After placing the anchor, the surgeon ties the suture through the soft tissue, connecting it to the eyelet of the bone anchor and thus reapproximating the soft tissue to the bone.
If multiple sutures are needed to attach the soft tissue, either technique is repeated multiple times at different locations in the bone, with a separate knot tied at each location. It is generally not possible to connect a series of anchors formed using the techniques described above, due to the difficulty of tightening stitches between the anchors.
SUMMARY
According to one aspect of the invention, fixation of soft tissue to bone or to other soft tissue is performed using a flowable material, e.g., a polymer, in place of, or in addition to, a conventional bone anchor. Because the flowable material generally infiltrates the porous cancelous bone (also known as the “trabecular network”), the flowable material effectively forms an anchor that extends under the stronger cortical bone. As a result, an anchor formed in this manner typically exhibits a high pull-out strength. In preferred implementations, bone fragments are incorporated into the flowable material as an autologous filler, to enhance regrowth of bone into the material during natural healing.
Using preferred surgical procedures and instruments of the invention, fixation can be performed endoscopically, rather than in an open surgical procedure, resulting in less invasive treatment with minimal trauma to the patient. In preferred implementations piercing of soft tissue, drilling of a cavity, delivery of a suture and/or bone anchor (if used), and injection of the flowable material into the cavity are performed using a single endoscopic surgical instrument. In some preferred implementations knot-tying, which tends to require considerable skill and dexterity and is generally time-consuming, is not necessary. Thus, the surgical procedures of the invention are generally relatively quick, reducing trauma, and relatively easy to perform. In some implementations, the methods of the invention allow a series of connected, tensioned stitches to be made to fix a region of soft tissue to bone.
In implementations in which a conventional bone anchor is not used with the flowable material, certain risks that may be associated with such bone anchors are eliminated. For example, if a suture is used the suture does not run through an eyelet, and thus will not be microscopically damaged by friction between the suture and eyelet. Also, anchors formed using a flowable material do not rely heavily on the quality and density of the bone in which the anchor is placed, and thus a placement in compromised, low density bone may still exhibit good holding power.
The invention also features surgical procedures involving endoscopic application of polymers for other purposes, e.g., to repair a bone defect, to fill holes that are left when bone plugs are harvested, to repair osteochondritis dessicans injuries, for repair or revision of ACL grafts that exhibit micromovement, for spine fusion, for meniscal repair, and to repair bone fractures. The use of endoscopic devices and techniques significantly reduces invasiveness, generally resulting in less trauma and quicker recovery.
In one aspect, the invention features a method of securing a fixation device within an opening in a tissue, including (a) delivering a material in a flowable state to the opening, and (b) changing the state of the material so that the material forms an interference fit that secures the fixation device in the opening. The fixation device may also be secured in the opening by other, supplemental means, e.g., threaded engagement, but at least a portion of the securing is provided by the interference fit.
Implementations of this aspect of the invention may include one or more of the following features. The tissue includes bone and/or soft tissue. The fixation device is selected from the group consisting of suture, anchors, and screws. The changing step includes allowing the material to at least partially harden. The changing step includes at least partially cross-linking the material. The material includes a polymer, e.g., a thermoplastic polymer. The material includes a hydrogel. The method further includes using the fixation device to secure a second tissue to the tissue having the opening. The tissue having the opening includes bone and the second tissue includes soft tissue. The method further includes, prior to delivery of the material, piercing the soft tissue; forming the opening in an underlying area of the bone; and delivering the fixation device through the pierced tissue; wherein the fixation device is constructed to hold the soft tissue in place against the bone. The fixation device includes a suture. The suture includes a region of increased surface area to enhance anchoring, e.g., a knot, barb, braided area, ball or shaped element. All of the steps of the method are performed endoscopically, for example the steps are performed using a single endoscopic surgical tool having a plurality of attachments, and the tool is not removed from the patient until after the steps are completed. The method further includes incorporating bone fragments, e.g., fragments generated during the forming step, into the material during or prior to the delivering step. The method further includes causing the material to infiltrate the trabecular network. The material includes an osteoconductive filler. The opening is formed using micro-tooling. The opening has a diameter of less than about 3 mm. The forming step includes forming the opening using a consumable cutting tool, and the delivering step includes causing the cutting tool to melt in response to frictional heat generated during the forming step. The forming step includes forming the opening with a cutting tool having a detachable portion, and the method further includes detaching the detachable portion in the opening after the forming step is completed, to serve as the fixation device.
In another aspect, the invention features a method of anchoring soft tissue to bone including (a) piercing the soft tissue; (b) forming an opening in an underlying area of the bone; (c) delivering a material, in a flowable state, to the opening; and (d) molding a portion of the material that is not in the opening to form a fixation device constructed to hold the soft tissue in place against the bone after the material changes state to a relatively less flowable state.
Implementations of this aspect of the invention may include one or more of the following features. The molding step includes forming a portion of the material into a shape that extends radially over a portion of the soft tissue surrounding the opening. The forming step includes drilling or abrading. All of the steps are performed endoscopically. The method further includes incorporating bone fragments generated during the forming step into the material during or prior to the delivering step. The material includes an osteoconductive filler. The method further includes causing the material to infiltrate the trabecular network The opening has a diameter of less than about 3 mm, more preferably from about
Harvie Fraser
Huckle James William
James Adam
Richardson Peter
Fish & Richardson P.C.
Lewis Ralph A.
Smith & Nephew Inc.
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