Microsurgical midline approach for the decompression of extraforaminal stenosis in L5-S1

Object. When performing surgery, the extraforaminal window is very narrow at the L5-S1 level. The authors describe a microsurgical method for decompression of the L-5 nerve root trapped between a marginal osteophyte of the vertebral body and the transverse process. The procedure was performed in 16 patients with extraforaminal stenosis. Methods. The cranial part of the L5-S1 facet joint and the caudal portion of the pedicle and transverse process of L-5 were removed via a midline skin incision and partial resection of the pars interarticularis; a high-speed drill was used as was a surgical microscope. The affected nerve root was decompressed and mobilized cranially. Postoperatively all patients reported excellent relief of their sciatic pain, and there were no technique-associated complications. There was no recurrence during the follow-up period, that ranged from 14 to 70 months. Conclusions. The authors recommend this technique for the effective decompression of symptomatic extraforaminal L5-S1 stenosis. The need for a dangerous and tedious removal of the vertebral osteophyte together with spinal fusion is avoided.