Clinical Research On Adjacent Segment Degeneration Following Dynesys Dynamic Stabilization System Versus Fusion Fixation For Lumbar Single Segment

ObjectiveTo estimate the clinical outcome and determine the differences of adjacent segment degeneration between dynesys dynamic stabilization system and fixation and interbody fusion for lumbar single segment.Methods40patients who were diagnosed with L4/5single segment LDH or LSS and uderwent lumbar posterior operation in Guangdong Provine Hospital of TCM from December2008to March2010were investigated. The patients were divided into two groups using two different approaches,20case of each. The observation group was decompressed with Dynesys dynamic f ixion, and the control group was decompressed with interbody fusion. The Visual Analogue Scale(VAS), Japanese Orthopaedic Assosiation Scores(JOA), Oswestry disability Index(ODI) and Macanb evulation standard were used to evaluated clinical effects for two groups. The upper and below adjacent segments degeneration(ASD) were evaluated by measuring the height of intervertebral space and the range of motion, using University of California at Los Angeles Grading Scal(UCLA) on X ray radiography. The Pfirrmann classifications was used to measure the degeneration of adjacent segment intervertebral discs on magnetic resonance image, and Weishaupt classifications were used to measure the degeneration of adjacent segment facet joints. PASWstatistics20.0statistical software was used to establish and analyize the database. P<0.05was considered statistically significant.ResultAll cases of the two groups were followd up.The observation group was followed up from48to64months after operation, averaging54.65months. The control group were followed up from47to60months after operation, averaging 52.60months. The excellent and good rate of the observation and control groups are90%and95%, without statistical significance. The VAS, JOA score and ODI percentage improve a lot in two groups at the final follow-up compared with the preoperative(P<0.01). The height of intervertebral space of both groups significantly reduce at the final follow-up compared with the preoperative(P <0.01). The ROM of adjacent segments increase in two groups, and there is difference at the final follow-up compared with the preoperative on upper adjacent segment of the observtion group(P<0.05), but significant difference on below(P<0.01);There is significant difference at the final follow-up compared with the preoperative on upper and below adjacent segments of the control group(P<0.01). The UCLA score increase in two groups, and there is difference at the final follow-up compared with the preoperation on upper and below adjacent segment of the observtion group(P<0.05), also the upper adjacent segment of the control group(P<0.05), but not on below adjacent segment (P>0.05).The Pffirrmann score increase in two groups, and there is difference at the final follow-up compared with the preoperation on upper adjacent segment of the observtion group(P<0.05), but no difference on below adjacent segment; there is difference at the final follow-up compared with the preoperation on upper and below adjacent segment of the control group(P<0.05).The Weishaupt score increase in two groups, and there is difference at the final follow-up compared with the preoperation on below adjacent segment of the observtion group (P<0.05), but no difference on upper adjacent segment (P>0.05);there is significant difference at the final follow-up compared with the preoperation on upper adjacent segment of the control group(P<0.01), but no difference on below adjacent segment. In observation group, there are10cases(14segments) with ASD, including7upper segments and7below segments, and the incidence is50%, with6males and4females, mean preoperative age58years, followed-up time52.9months. There are13cases (17segments) with ASD in control group, including10upper segmengs and7below segments, and the incidence is65%, with10males and13females, mean preoperative age55.15years, followed-up time53.85months. The incidence of two group has no difference (P>0.05), als no difference comparing male with female, between upper and below segments. On the whole, there are23cases with ASD,10males and13females, mean preoperative age56.39years, followed-up time53.43months. There31segments are diagnosed ASD, with17upper segments and14below segments.ConclusionDynesys dynamic stabilization system can obtain satisfactory clinical efficacy as same as Fusion Fixation in treament of degenerative lumbar disease (LDH or LSS) in the mid-term follow-up, but it can not prevent or delay adjacent segment degenerating.