The Preventive Effect of Dynamic Stabilization against Adjacent Segment Degeneration after Posterior Lumbar Interbody Fusion.

Study Design. Retrospective cohort study. Objective. To investigate the effects of dynamic stabilization with sublaminar taping (ST) on the upper segment adjacent to posterior lumbar interbody fusion (PLIF). Summary of Background Data. Hybrid procedures such as dynamic stabilization for adjacent segment in addition to spinal fusion have been developed for reduction of the mechanical stress and prevention of adjacent segment pathology (ASP). However, a few reports are available on hybrid procedures and their efficacy is still controversial. Methods. Of the 116 patients who underwent L4/5 PLIF between August 2006 and September 2012, 76 patients with minimum 2-year follow up were included in this study. Fifty three patients underwent L4/5 PLIF with hybrid procedure using ST on L3 lamina (group U), and 23 patients underwent conventional L4/5 PLIF (group C). The adjacent segment degeneration (ASDeg) was determined by measurements of radiograph, computed tomography, and magnetic resonance imaging; the adjacent segment disease (ASDis) was evaluated on medical records. Results. The incidence of ASDeg at L3/4 segment of group U (3.7%) was significantly less than that of group C (30.4%) (P = 0.003), although there were no significant differences at L2/3 (group U, 7.5%; group C, 13%) or L5/S1 segment (group U, 5.7%; group C, 8.7%). On the other hand, no significant difference was found between two groups in the incidence of ASDis in L2/3 to L5/S1 levels, and no patient underwent reoperation. Bivariable and multivariable logistic regression analyses for L3/4 segment ASDeg revealed that the difference of surgical procedure was the only significant factor. Conclusion. The current study showed that L4/5 PLIF with hybrid procedure using ST on L3 lamina significantly reduced the incidence of L3/4 ASDeg as compared with the conventional L4/5 PLIF without compromising L2/3 or L5/S1 segment. Although further studies and longer follow up are necessary, the hybrid procedure is expected to be effective for preventing ASP.