Efficacy of Topping-Off Surgery in Preventing Adjacent Segment Degeneration of the Lumbar Spine: A Radiographic Study

Abstract

Introduction The aim of the study is to investigate the image change of adjacent segment degeneration after topping-off (posterior lumbar interbody fusion + above segment interspinous implant). Materials and Methods All lumbar spinal stenosis cases from the department of orthopedics of Beijing Chaoyang Hospital that received PLIF + above segment Coflex between August 2008 and October 2012 were analyzed retrospectively. Analysis the gender, age, body mass index of all the patients was done. The X-ray films before and after surgery were measured and got some data (total lordosis, the height of disc, range of motion, lordosis and olithesis). Modic changes (modic grades) of endplate and disc changes (modified Pfirrmann grades) were recorded. All data used SPSS 12.0 to analysis. Results There were 32 patients in Topping-off (male 21, female 11), including group 1 (L4/5 PLIF+L5S1 Coflex) 12 patients and group 2 (L3/4 PLIF+ L4/5 Coflex) 20 patients. Age averaged 61.5 years old (range, 30-79 years), follow-up averaged 24.6 months (range, 63-11 years). The average surgery time was 110 ± 21 minutes. The average blood loss was 401 ± 110 mL. Postoperatively, the ODI, JOA, and VAS score improved. There was no significant difference in the height of disc of the Coflex segment and above segment between before and after surgery. Segmental lordosis of Coflex and total lordosis were all increased significantly ( t = −1.9 and −2.0, p < 0.05). There was no significant difference in the number of the disc change by modic grade of endplate ( p > 0.05). Preoperative MRI: the disc change of Coflex segment (modified Pfirrmann grades)—9 patients grade 4, 15 patients grade 5, 8 patients grade 6 and modic changes of endplate 6 patients grade 2, 4 patients grade 1, all the others grade 0. The adjacent segment (modified Pfirrmann grades) 27 patients grade 1, 5 patients grade 2, and all the patients of the modic changes of endplate grade 0; over 24 months postoperation 24 patients made MRI, there was no significant difference in the number of the disc changes and modic changes of endplate ( p > 0.05). Conclusion Topping-off surgery is fit for the patients who have serious stenosis of lumbar spinal cord with mild and moderate stenosis of adjacent segment, which can restrict the adjacent segment's range of motion in both extension and flexion, also can sustain the height of Coflex segment. After follow-up over 24 months, MRI indicates that topping-off surgery can prevent the adjacent segmental degeneration. Disclosure of Interest None declared