Clinical outcome of different lumbar instrumentation with or without fusion and its effect on adjacent segment degeneration in lumbar degenerative diseases

English Keywords:Lumbar vertebrae  Internal fixation  Adjacent segment  Intervertebral disc degeneration  Magnetic Resonance  T1ρ

English Abstract:

  【Abstract】 Objectives: To compare the clinical effects of posterior lumbar interbody fusion(PLIF) and Wallis interspinous implant in lumbar disc herniation or stenosis complicated with instability, and their effects on adjacent segment degeneration. Methods: A retrospective study of 61 patients undergoing PLIF or interspinous Wallis placement at L4/5 segment was carried out. Among these, 29 patients were diagnosed as lumbar disc herniation and 32 patients as lumbar stenosis, all of them were complicated with lumbar instability. All patients presented with low back pain. In this study, 32 cases underwent PLIF, and 29 underwent interspinous Wallis placement. The clinical results were assessed and compared by JOA score and Oswestry disability index(ODI) preoperatively, 1 month and 1 year postoperatively and at the final follow-up. The degenerative grades of adjacent segments of L3/4 and L5/S1 were recorded by using UCLA(university of California at Los Angeles) grading system. The T1ρ values of nucleus pulposus in adjacent segments of L3/4 and L5/S1 were also measured at the same time points. Results: The average follow-up period was 61.3 months(range: 48-77 months), and the average follow-up period for the PLIF and Wallis group was 63.4 and 59.6 months respectively, which showed no significant difference between groups(P>0.05). There were no significant differences with respect to the age, sex ratio, disease ratio, degenerative grading and T1ρ values of adjacent segment discs preoperatively(P>0.05). The recovery rate of ODI, JOA score for PLIF and Wallis groups was 76.1%, 69.2% and 78.5%, 75.0% respectively, which showed no significant difference between 2 groups(P=0.78, 0.85). According to the UCLA classification, no significant difference was found in the degenerative grading for adjacent segment of L3/4 and L5/S1 at the final follow-up(P=0.91, 0.70). The T1ρ value of L3/4 disc in the PLIF group preoperatively, 1 month postoperatively and at the final follow-up was 115.4±8.9ms, 111.6±12.3ms and 91.6±11.1ms respectively, and 112.4±10.0ms, 109.9±9.2ms and 103.5±10.8ms in the Wallis group respectively. The T1ρ value of L5/S1 disc in the PLIF group preoperatively, 1 month postoperatively and at the final follow-up was 95.4±7.7ms, 94.6±9.6ms and 88.1±12.6ms respectively, and 96.3±9.2ms, 95.4±8.5ms and 91.3±11.4ms respectively. There were no significant differences in the T1ρ value of L3/4 and L5/S1 disc compared with preoperative ones, at 1 month after operation in each group(PLIF: P=0.67, 0.75; Wallis: P=0.72, 0.64). The T1ρ value of L3/4 in PLIF group significantly decreased at the final follow-up, compared with that in the Wallis group(P=0.02). However, there was no significant difference in the T1ρ value of L5/S1 at the final follow-up between 2 groups(P=0.89). Conclusions: Both of the PLIF and the interspinous placement can achieve satisfactory clinical results for lumbar degenerative disease at the midterm follow-up, however the interspinous placement is superior to the PLIF in delaying the cranial adjacent segment degeneration.