Adjacent Segment Disease

The goal of this clinical trial is to learn whether microdecompression alone is as effective as decompression with extension of fusion surgery in patients with symptomatic adjacent segment stenosis after previous lumbar fusion surgery. The main questions it aims to answer are: Is microdecompression alone non-inferior to decompression with extension of fusion in improving disability 24 months after surgery, as measured by the Oswestry Disability Index (ODI)? Does microdecompression alone result in similar or lower rates of complications, reoperations, pain, and radiological progression compared with decompression and fusion? Researchers will compare microdecompression alone to decompression with extension of lumbar fusion to determine whether the less invasive procedure can achieve similar clinical outcomes while reducing surgical burden and preserving spinal structures. Participants will: Be randomly assigned to one of two treatment groups: microdecompression alone or decompression with extension of lumbar fusion. Undergo the assigned surgical treatment. Attend clinical and radiological follow-up visits at 6, 12, and 24 months after surgery. Complete questionnaires assessing disability, pain, quality of life, sleep quality, and mental health. Undergo routine imaging and clinical examinations to evaluate treatment outcomes and possible complications.

Adjacent segment disease (ASD) in the lumbar spine is a well-known sequela of lumbar fusion surgery. The annual incidence of adjacent level re-operation is approximately 3% with a ten-year prevalence of 20-30%. Frequently, the surgical treatment involves decompression of the adjacent level coupled with extension of the instrumentation and fusion. Advocates of this paradigm cite the altered kinematics and biomechanics of levels adjacent to a lumbar fusion mass. Furthermore, decompressed levels adjacent to a fused segments are associated with higher rates of ASD in retrospective studies. Yet, a retrospective review of higher quality data concluded decompression adjacent to single-level fusion provides similar outcomes compared to fusions extending across the decompressed segments. Given the conflicting data currently available, higher quality data are needed to guide surgical decision-making in ASD. The purpose of this trial is to prospectively compare decompression and decompression with fusion in patients with lumbar ASD.