Abstract: A wedge-shaped prosthetic spinal disc nucleus including a hydrogel core surrounded by a constraining jacket. The hydrogel core is preshaped to form the wedge shape in a hydrated state. The constraining jacket is flexible, but substantially inelastic and is configured to prevent the hydrogel core from conforming to an anulus upon hydration. The prosthetic spinal disc nucleus corresponds generally to anatomical variations in disc space geometry, generally defined by separable areas or compartments, thus improving performance. In one preferred embodiment, the prosthetic spinal disc nucleus includes a radiopaque marker for indicating a location and orientation following implant.

Abstract: A trial implant for evaluating a size of an intradiscal space for subsequent implantation of a prosthetic spinal disc nucleus. The trial implant is comprised of an elongated central body and a retrieving body. The elongated body is formed from a rigid, surgically safe material and preferably has a volume less than a volume of a nucleus cavity portion of the intradiscal space. The retrieving body is associated with the central body and is configured to facilitate retrieval of the trial implant from an enclosed area, such as the nucleus cavity. A plurality of trial implants are included with a trial implant kit, with each of the plurality of trial implants housing a different size and/or shape. During use, the trial implant provides an indication as to whether a similarly sized prosthetic spinal disc nucleus will fit within a particular intradiscal space.

Abstract: A method for performing a surgical procedure includes the steps of providing a surgical retractor including a sleeve member having two opposed retractor arms at its distal end portion, at least partially inserting the retractor arms of the retractor within a space defined between adjacent bony structures whereby first and second supporting surfaces of each retractor arm respectively engage the opposed structures thereby distracting the structures, and performing the surgical procedure. A method for inserting a spinal implant is also disclosed. Instrumentation for performing the procedure is also disclosed.

Abstract: A vertebral spacer apparatus includes an elongated member having proximal and distal end portions and defining a longitudinal axis and a vertebral spacer which is releasably mounted to the elongated member. The vertebral spacer includes an insertion end portion and a trailing end portion. The insertion end portion is configured to at least span an intervertebral space defined between adjacent vertebrae. The trailing end portion defines a dimension greater than a corresponding dimension of the insertion end portion and is sized to prevent entry thereof within the intervertebral space.The insertion end portion preferably includes first and second opposed support surfaces wherein a dimension defined between the first and second support surfaces at least spans the intervertebral space between adjacent vertebrae. A method for implanting a fusion implant with the vertebral spacer apparatus is also disclosed.

Abstract: A capsule-shaped prosthetic spinal disc nucleus for implantation into a human intradiscal space, made of a substantially inelastic constraining jacket surrounding an amorphous polymer core. The constraining jacket has a generally fixed maximum volume and defines a height. The amorphous polymer core fills an initial volume of the constraining jacket and develops an internal pressure. In response to the internal pressure, the constraining jacket transitions toward the maximum volume, increasing substantially in height.

Abstract: An elongated, capsule shaped prosthetic spinal disc nucleus body for implantation into a human inter vertebral spinal disc, made of a hydrogel core and a constraining jacket surrounding the hydrogel core that permits the hydrogel core to deform and reform. The constraining jacket is configured to allow the hydrogel core to hydrate to a predetermined volume and will deform and reform in a desired fashion in response to various loads placed upon the spinal tract. The prosthetic spinal disc nucleus assists in restoring the natural physiology of the human intervertebral disc. By implanting two prosthetic spinal disc nuclei side-by-side into a damaged disc of a human spine, both height and motion can be maintained.

Abstract: An elongated, pillow shaped prosthetic spinal disc nucleus body for implantation into a human intervertebral spinal disc, made of a hydrogel core and a flexible constraining jacket surrounding the hydrogel material core that permits the hydrogel core to expand and contract. The hydrogel core has a length approximating the sagittal diameter of a nucleus of the human disc, a width less than the length, and a height less than the length or width. The hydrogel core will expand and contract in a desired fashion as it imbibes and expels fluids in response to various loads placed upon the spinal tract. The constraining jacket is porous to allow fluids to pass through to the hydrogel core, but prevents the hydrogel from escaping, thus fostering the natural physiology of the human intervertebral disc. By implanting two prosthetic spinal disc nucleus bodies side-by-side into a damaged disc of a human spine, both height and motion can be maintained.

Abstract: A surgical method and tools for anchoring a suture to bone is disclosed. The method includes forming an opening through a top surface of the bone, positioning a suture within the opening and crimping a region of the top surface of the bone surrounding the opening to anchor the suture within the opening. The tools used with the disclosed surgical method include a punch, a broach, a guide and a swage. The punch and the broach are used to create a uniform diameter opening in the bone by compressing bone material. The guide is used to position a suture, preferably having a shoulder, in the opening. Finally, the suture is used to crimp the region of the top surface of the bone surrounding the opening.

Abstract: A spinal anulus cutter for cutting a multisided flap in an encapsulating ligament, such as an anulus of a human intervertebral disc, to provide access to an interior space or material surrounded by the ligament. The spinal anulus cutter is characterized by a knife blade comprised of a plurality of walls which are connected together to define a closed side and an open side. Further, a cutting edge is formed at the forward edge of the walls which is configured to cut the multisided flap in the ligament when an axial force is transmitted to the knife blade in a direction towards the cutting edge. The flap will conform in shape and size to the form of the knife blade, whereby the open side of the knife blade will not cut the ligamentary tissue.

Abstract: A method for surgically implanting a prosthetic spinal disc nucleus body into a human spinal disc space is disclosed. The spinal disc space contains adjacent vertebrae and an anulus having a posterior side. The method includes cutting a flap through the anulus in the disc space to create an opening. The vertebrae adjacent to the disc space are slightly separated and a prosthetic spinal disc nucleus body is inserted through the opening into the disc space.

Abstract: When an intervertebral fusion is required, and the disc space is unusualy large, that disc space can be preserved by surgically implanting a pair of relatively large male-thread fusion cages 20, 20A with their threads 13 overlapping. Because of their large size, such fusion cages 20, 20A should be implanted by an anterior approach to the lower back. When each of the cages is made of a shape-retaining helix 22 of wire that is hollow within the helix 22 and has openings 23 between adjacent turns, the cages 20, 20A can be removed after the adjacent vertebrae have become fused together and without disrupting that fusion, thus guarding against possible rejection of the cages 20, 20A by the patient's body. The anterior approach and scaled-down fusion cages 20, 20A may be used in cervical spine fusions.

Abstract: A fusion cage 10 having an external thread 12 can be surgically inserted into a threaded bore extending laterally between the adjacent bony structures such as two vertebrae 94, 95 with the thread 12 penetrating into cancellous bone of each of the vertebrae 94, 95. The fusion cage 10 is easily screwed into place by hand without damage to the bony structures 94, 95. Cage 10 is then packed with a bone-growth-inducing substance such as cancellous bone. When a pair of such cages 10 are implanted between adjacent vertebrae 94, 95, patients have been able to sit without pain by the second or third day, much earlier than has been possible in prior spinal fusions except those involving steel plates and screws. Eventually, the ingrowth of bone through perforations 13 in the valley 14 of the thread 12 of the fusion cage 10 forms a permanent interconnection between the two bony structures 94, 95.

Abstract: During back surgery, a surgeon can, with one hand, apply traction against tissue in a surgical wound by using a retraction device that includes an upstanding post and a surgical retractor, the handle of which is formed with ratchet teeth for securing the retractor to the post against elastic recoil of the retracted tissue. The post preferably is integral with a slip-lock which can be slidably mounted on a rectangular rail of a framework that extends above the patient. The slip-lock includes a floating jaw that is loosely pinned to a slide and becomes releasably locked to the rail when the elastic recoil of retracted tissue pulls on the post. Because the retraction device holds the tissue precisely in the position to which it is set by the surgeon, the hazards involved in using assistants to hold retractors are avoided.

Abstract: A fusion cage 10 includes a cage body defining an internal cavity with an inner surface and an outer surface. The outer surface defines a helical thread 12 comprised of a plurality of turns which define valleys 14 therebetween. Located in the valleys 14 are perforations 13 which provide communication between the outer surface and the interior cavity. Thus, when the fusion cage 10 is mated to a bone structure and the internnal cavity is packed with bone chips or other bone-growth-inducing substances, there is immediate contact between the bone structure and the bone chips through the perforations 13.

Abstract: A bone impactor consists of a single piece of lightweight metal which has a handle and a smooth shank, across the tip of which extends a working surface that may be fitted against an excrescence, followed by striking the butt end of the handle to compress the excrescence into the bone to relieve pressure on a nerve. The shank of the bone impactor terminates in a foot that tapers to a toe, and a flat working surface beneath the foot makes an angle of at least 95.degree. with the longitudinal axis of the shank.

Abstract: By implanting two prosthetic disc capsules side-by-side into a damaged disc of a human spine, both height and motion, including front-to-back bending, can be maintained. Each prosthetic disc capsule has a bladder enclosing a fluid containing a therapeutic material that is slowly diffusible through a semi-permeable membrane of the bladder. The fluid filling the semi-permeable membrane preferably is an aqueous solution that has gel-like properties that afford a viscosity and velocity-shear behavior imitating the natural rheology of intradiscal nuclear tissue. Those properties are obtained when the aqueous solution is of a mucopolysaccharide such as hyaluronic acid or soldium hyaluronate.

Abstract: A known kneeling attachment to an operating table includes a platform on which a patient kneels with the torso positioned over one end of the operating table while the buttocks rest against a buttocks support including a rigid U-shaped yoke, the arms of which are connected to opposite sides of the operating table. In the buttocks support of the invention, the arms of the U-shaped yoke are connected to the inboard end of the platform, and a mast fixed to the crosspiece of the yoke is telescopically connected to the outboard end of the platform. This permits the yoke to be lowered to the level of the platform, thus allowing a patient to kneel on or dismount from the platform without first disconnecting the yoke. By making the platform of radiotransparent materials, x-ray beams can pass from a generator positioned beneath the platform, through the front of the patient's body, and to an image tube positioned above the patient's back.

Abstract: For use in back surgery, a known kneeling attachment to an operating table has a platform on which a patient kneels with the torso positioned over one end of an operating table and the buttocks resting against the padded crosspiece of a rigid U-shaped yoke. The invention concerns a substantially rectangular rigid frame which can be mounted on the yoke with an outboard crossarm of the frame attached to the crosspiece of the yoke and the inboard end of the frame attached to the arms of the yoke. The frame is useful for supporting surgical instruments such as retractors at a surgical wound, in particular a retraction device that a surgeon can adjust with one hand, even without looking. The frame also makes possible a new surgical procedure by which a dislocated vertebra can be moved into position by a lifting mechanism suspended from the frame.

Abstract: Particulate bone is more easily and quickly guided into position for impaction into the site of a fusion mass by using a surgical funnel provided by an elongated, thin, flat base and a pair of thin, upstanding walls which extend along the elongated edges of the base to provide a chute. While the outlet of the funnel rests against the recipient site, particulate bond is incrementally pushed from the chute and tamped to build a fushion mass. By doing so, the particulate bone is much less likely to become contaminated by soft tissues. Preferably the reservoir provided by the upstanding walls is large enough to hold sufficient particulate bond to complete one side of a usual fusion mass so that the funnel can be left in position during that part of the surgical procedure. The funnel can be a single piece of metal or plastic.