Surgical refinement on the lumbar interbody fusion has been undertaken both in procedure and instrumentation. From 1970 to 1990, a total of 165 cases of lumber interbody fusion was performed with anterior retroperitoneal or posterior interlaminar approach.
Method: Autogenous bone grafts were taken from the iliac bone. The shape of the bone graft was eotjer square peg or round dowel. In retroperitoneal method, lumbar sympathectomy approach was used and in the posterior method, interlaminar fenestration method was preferred. The procedure consisted of thorugh removal of soft tissue from the interespace and snug insertion of autogenous bone graft. Round bone dowel 12㎜ in diameter, 15-20㎜ in thickness or similar size of square pegwere used. The upper surface of graft should be packed 3-5㎜ deeper than the posterior rims of the vertebral bodies.
Immediately after the surgery, the result was checked by plain X-rays and/or CT scan. In follow-up, solid fusion was confirmed in 70% of retroperitoneal method and 87% of posterior round dowel insertion and 85% of posterior square peg graft. The others showed fibrous fusion. Pedicle screw fixation was added in 5 cases. Strong full-thickness of bone and close contact between bone graft and vertebral bodies assures solid fusion.
Square peg graf was more difficult to make standard size in comparison with round dowel which was taken by using dowel bone cutter. Retropulsion of the bone graft occured in square peg with higher frequency than round dowel. Newly deviced instruments were interchangeable drills, rounded tip drill, slender bone graft impactor, slender ring curette, osteophyte impactor. They are easy to use, safe and efficient for the precise and accurate microsurgery.
Posterior lumbar interbody fusion using round dowel graft and refined instrumen-tation assured close contact between graft and vertebral bodies, and safe and easy procedures and uktimately showed better results.
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