PLIF FOR ADULT LUMBAR DEGENERATIVE SCOLIOSIS

Abstract

Introduction The management of severe pain associated with progressive adult scoliosis remains a challenging problem. Radicular symptoms are often caused by bony foraminal stenosis and significant global and segmental imbalance may exist in both the sagittal and coronal planes. The patients are often elderly and have intercurrent medical conditions. The use of disc space distraction, pedicle screw instrumentation and posterior lumbar interbody fusion (PLIF) with Insert and Rotate prostheses has been shown to be effective in the correction of sagittal plane deformity (1). The current study examines the safety, clinical and radiological efficacy of this technique in the management of adult multilevel scoliosis.

Methods A prospective single cohort observational study of 15 consecutive patients with a degenerative scoliosis of 20 degrees or greater managed using an Insert and Rotate PLIF technique between October 2000 and July 2003. The minimum follow-up was 2 years. Clinical outcome measures included VAS pain score, SF-12, LBOS and Patient Satisfaction survey. Pre- and post-operative measures of radiological sagittal and coronal deformity were manually obtained. Wilcoxon signed-ranks test and Spearman’s non parametric test for correlation were used with significance set at 0.05.

Results The median age was 72 years (range: 56–80). Male: female ratio was 6:9. PLIF was carried out at 2 levels in 7 patients, 3–5 levels in 8 patients. Median blood loss was 1100mls for 2 level patients and 2550mls for 3–5 level patients. Operating time was 345mins and 545mins in the 2 and 3–5 level cases respectively. Median pre-operative scoliosis was 31degrees (range: 20–65) and post-operatively measured 14degrees (range: 0–30, p=0.001). Median pre-op VAS of 53 reduced to 20 (p=0.003). LBOS improved from 24 to 37 (p=0.004). A correlation was found between the amount of pre-operative coronal plane deformity and the post-operative VAS (r=0.6, p=0.003). 13 of the 15 patients considered the procedure was worthwhile and that they would have it again under similar circumstances. Early post-operative complications included electrolyte/fluid disturbance in 2 patients, 2 cardiac arrhythmias, one DVT/PE and 2 returns to the O.R. for pain caused by a misplaced pedicle screw or bone graft. One patient developed a progressive scoliosis above the fusion and one a pathological wedge compression fracture. 4 patients required late surgery including 2 who had been fused down to L5 and required extension of their fusion to the sacrum for pain associated with an L5/S1 foraminal stenosis and one who developed a painful non-union.

Discussion PLIF with an Insert and Rotate technique following disc space distraction for severe and progressive adult scoliotic deformity is technically difficult and can be associated with significant peri-operative morbidity. Nevertheless, the reported satisfaction rates by the patients in this small series are encouraging and the procedure appears to have achieved substantial correction of global and segmental deformity in both the coronal and sagittal planes. Whether this will be beneficial in the long term requires further study.