[POSTERIOR LUMBAR INTERBODY FUSION FOR DOUBLE-SEGMENTAL BILATERAL ISTHMIC LUMBAR SPONDYLOLISTHESIS]

To explore the effectiveness of posterior lumbar interbody fusion in the treatment of double-segmental bilateral isthmic lumbar spondylolisthesis.

Between February 2008 and December 2013, 17 patients with double-segmental bilateral isthmic lumbar spondylolisthesis were treated with posterior lumbar interbody fusion. There were 12 males and 5 females, with an age ranged 48-69 years (mean, 55.4 years). The disease duration ranged from 11 months to 17 years (median, 22 months). According to the Meyerding classification, 30 vertebrea were rated as degree I, 3 as degree II, and 1 as degree III. L₄,₅ was involved in 14 cases and L₃,₄ in 3 cases. The preoperative visual analogue scale (VAS) score was 8.6 ± 3.2.

Cerebrospinal fluid leakage occurred in 2 cases because of intraoperative dural tear; primary healing of incision was obtained, with no operation related complication in the other patients. The patients were followed up 1-6 years (mean, 3.4 years). At last follow-up, VAS score was decreased significantly to 1.1 ± 0.4, showing significant difference when compared with preoperative score (t=7.652, P=0.008). X-ray films showed that slippage vertebral body obtained different degree of reduction, with a complete reduction rate of 85% (29/34) at 1 week after operation. All patients achieved bony union at 6-12 months (mean, 7.4 months). According to the Lenke classification, 13 cases were rated as grade A and 4 cases as grade B. No internal fixation loosening and fracture were observed during the follow-up. Intervertebral disc height was maintained, no loss of spondylolisthesis reduction was found.

It can obtain satisfactory clinical result to use spinal canal decompression by posterior approach, and screw fixation for posterior fusion in treatment of double-segmental bilateral isthmic lumbar spondylolisthesis. The key points to successful operation include accurate insertion of screw, effective decompression, distraction before reduction, rational use of pulling screws, and interbody fusion.