Complications of lumbar spinal fusion with transpedicular instrumentation

Transpedicular screw fixation systems are coming into wide use as an adjunct to lumbar spinal fusion procedures. This 5-year series included 486 patients who underwent 533 variable screw placement procedures for discal, degenerative, and spondylolytic problems. The wound infection rate was 2.6%: 0.6% deep, 0.9% graft, and 1.1% superficial. The neural injury rate was 1.1% overall: 0.6% related to posterior lumbar interbody fusion and 0.6% related to instrumentation. Technical problems per procedure included 8.1% difficult screw placement, 5.6% nut loosening, and 4.3% screw breakage (1.1% per screw placed). Device modifications have reduced the incidence of screw breakage and nut loosening. No device-related neural injuries occurred in the last 333 procedures. With experience, the device can be applied safely without significantly increasing the risk of neural injury or morbidity.