The Efficacy of Lumbar Hybrid Stabilization Using the DIAM to Delay Adjacent Segment Degeneration: An Intervention Comparison Study With a Minimum 2-Year Follow-up

BACKGROUND: Although posterior lumbar interbody fusion (PLIF) has a successful fusion rate, the long-term outcome of PLIF is occasionally below expectations because of adjacent segment degeneration (ASD). OBJECTIVE: To evaluate the ability of hybrid stabilization using DIAM (Device for Interspinous Assisted Motion) to delay ASD. METHODS: An intervention comparison study of 75 patients (hybrid, 25; PLIF, 50) was performed. The indications for hybrid stabilization were facet joint degeneration, Pfirrmann grade II to III, and stenosis at the rostral adjacent segment. The PLIF group consisted of patients matched for age, sex, and fusion. The hybrid stabilization procedure included traditional PLIF and DIAM installation at a superior adjacent segment. The outcomes were analyzed with a linear mixed model analysis. Conditional logistic regression was performed to calculate the odds ratio for the association of surgical methods. RESULTS: The hybrid group (24%) revealed fewer ASDs than the PLIF group (48%). Among ASDs, spondylolisthesis occurred more frequently in the PLIF group than the hybrid group. Hybrid surgery was significantly associated with ASD; the odds ratio for hybrid surgery was 0.28 compared with PLIF. Foraminal height of the PLIF group decreased more than the hybrid group (P = .01). Segmental mobility showed a greater increase in the PLIF group than the hybrid group (P = .04). However, the clinical outcomes did not show significant differences between the groups. CONCLUSION: Hybrid stabilization with DIAM and pedicle screws can be used for patients with facet degeneration at adjacent segments but should be further investigated.