Introduction: Minimally invasive laminectomy with concomitant in situ fusion is an effective surgical treatment for lumbar spinal stenosis, although development of adjacent segment disease (ASD) is a viable concern. Reports on the rates of ASD and reoperation following this procedure are rare. The goal of the study is to investigate the occurrence of clinical ASD and reoperation rates subsequent to minimally invasive laminectomy (MIL) with in situ posterior fusion (ISPF).
Methods: 280 MIL with ISPF was performed on 155 consecutive patients with lumbar stenosis refractory to conventional treatments. Clinical ASD was defined as symptomatic radiculopathy, stenosis, and/or instability that occurred at a level immediately adjacent to the index foci =6 months after initial postoperative relief. Clinical outcomes were evaluated with Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Short Form-36 (SF-36) Physical and Mental Component Scores.
Results: Recurrence of symptoms developed in 7 (4.5%) cases subsequently, 5 (3.2%) of which occurred at the same level as surgery. The other 2 (1.3%) occurred at the immediately superior levels and represented clinical ASD. Of these 7 recurrent cases, reoperation was carried out in 5 (3.2%) cases, with 4 (2.6%) requiring same-level surgery and 1 (0.6%) requiring adjacent segment surgery. At 24 months follow-up, VAS improved from 6.0 at preoperative baseline to 3.6 (40%), ODI improved from 38.0 to 22.5 (40.8%), SF-36 Mental Component improved from 46.9 to 54.0 (13.1%), and SF-36 Physical Component improved from 30.5 to 35.6 (16.7%); statistical significance was achieved at all but one time point.
Conclusions: Muscle-sparing minimally invasive laminectomy with in situ fusion was associated with a low rate of clinical ASD (1.3%) and ASD-related reoperation (0.6%), while achieving successful postoperative outcomes. Minimally invasive spine surgery represents a desirable approach that minimizes ASD risks in treating lumbar stenosis.
Patient Care: This study found low rates of adjacent segment disease and re-operation following minimally invasive laminectomy with in-situ fusion. This conclusion suggests that a muscle-sparing minimally invasive approach is critical to reducing postsurgical changes and associated pathologies, resulting in excellent surgical outcomes and patient satisfaction.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Understand the use of MIL with ISPF to treat uncomplicated lumbar spinal stenosis.
2) Gain knowledge about the physiological foundation of ASD, and the scientific evidence that favors a muscle-sparing minimally invasive approach.
3) Understand that low rates of ASD and re-operation associated with this approach underscore its safety and effectiveness.