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: An introduction set 20 is adapted for positioning a probe 22 relative to a desired site in a subject 128. The introduction set 20 includes an elongated flexible trocar 24 adapted for insertion into the subject 128 relative to the desired site. The trocar 24 has a flexible body 34 adapted to be bent out of the way of the equipment. The introduction set 20 further includes a curved cannula 26 having an elongated arcuate tubular body 60 and an elongate friction reducing tubular lining 64 disposed within the tubular body 60. The introduction set 20 further includes a dilator 28 which can be disposed in the cannula 26 for facilitating the introduction of the cannula 26 into the subject 128. The cannula 26 and dilator 28 are inserted over the trocar 24. The trocar 24 is of sufficient length such that, with the cannula 26 completely thread over the trocar 24, the trocar 24 extends from the back end 44 of the cannula 26 so that the position of the trocar 24 can be continuously monitored and maintained.

Abstract: A percutaneous discectomy system 10 includes a discectomy device 12 having a needle 16 with a port 48 and a flared cutting edge 44 which is actuated past the port 48 to sever tissue provided adjacent thereto. An irrigation device is 18 are provided for irrigating the area adjacent the tip 46 of the needle 16 to assist a vacuum device 22 in aspirating the severed tissue away from the disc. The discectomy system 10 assists in the removal of herniated disc tissue in order to relieve pressure on the nerves located adjacent thereto. In addition, the needle 16 is flexible so that it can be temporarily or permanently bent around other body tissues such as the pelvis in order to access discs which are surgically hard to reach otherwise.