OBJECTIVETo explore internal fixation whether can improve the clinical outcomes of decompression and posterolateral fusion in patients with degenerative lumbar spondylolisthesis.

METHODSFrom December 1998 to December 2005, 49 patients who had degenerative lumbar spondylolisthesis underwent decompression and posterolateral fusion without (group A, 21 cases) or with (group B, 28 cases) internal fixation (CD HORIZON M8 system). There were 12 males and 37 females with a mean age of 58.5 years (range, from 49 to 68 years). Among them,32 cases were grade I and 17 were grade II according to Meyerding grade system. All patients were followed up with an average of 58 months (range from 12 to 90 months). The pain of low back and leg (VAS scoring), spinal active function and neurologic function were evaluated according the assessment system of Yuan.

RESULTSThe VAS score of low back in group A and B were respectively 41.9 +/- 7.5 and 32.8 +/- 6.2 at follow-up; and VAS score of leg in group A and B were respectively 33.9 +/- 7.3 and 30.8 +/- 6.2. Spinal active function of patients, 15 cases obtained improvement, 6 cases aggravation or no improvement in group A; 25 cases obtained improvement, 3 cases aggravation or no improvement in group B. Neurologic function of patients, 15 cases obtained improvement, 6 cases aggravation or no improvement in group A; 26 cases obtained improvement, 2 cases aggravation or no improvement in group B. The group B was better than group A in the aspect of low back pain, spine active function and neurologic function (P < 0.05). There was no statistically significant difference in improvement of leg pain between two groups (P > 0.05).

CONCLUSIONUsing internal fixation in decompression and posterolateral fusion for degenerative lumbar spondylolisthesis can improve low back pain and clinical function. Decompression is necessary for the surgical treatment of degenerative spondylolisthesis, which is major effect on the improvement of leg pain.