Journal of Neurosurgery: Spine. 2026;45(3):339-346
Lumbar stenosis affecting adjacent levels does not necessarily imply that every symptomatic segment requires fusion. The operative challenge is to distinguish the level requiring stabilization from a neighboring stenotic segment that can be decompressed without compromising its mechanical integrity. Farooq and colleagues evaluate a hybrid strategy combining single-level minimally invasive transforaminal lumbar interbody fusion with adjacent-level unilateral laminotomy for bilateral decompression. Their experience provides preliminary clinical support for selective fusion in carefully chosen patients, while emphasizing that preservation of the adjacent segment depends on both preoperative stability and a structure-preserving decompression.
Objective
To assess reoperation after the one-and-a-half MIS-TLIF procedure, particularly subsequent extension of fusion to the adjacent decompressed segment, together with clinical and radiographic outcomes.
Methods
This retrospective single-center series evaluated operations performed by one experienced surgeon between January 2016 and February 2023. Of 36 patients considered, 33 met the inclusion criteria. Mean age was 67.9 years. Patients had degenerative lumbar disease with radiculopathy and mechanical back pain unresponsive to conservative treatment. The strategy combined MIS-TLIF using an expandable cage at the unstable segment with unilateral laminotomy for bilateral decompression (ULBD) at an adjacent stenotic level. The authors specify that adjacent-level decompression was restricted to segments without dynamic instability.
Outcomes included complications, reoperations, back and leg pain, disability and radiographic measures. Median clinical follow-up was 26 months. Complete serial imaging was available for 26 patients, with a median radiographic follow-up of 11.7 months. Fusion assessment relied primarily on standing and dynamic radiographs; CT was used when available rather than obtained routinely.
Main results
Three patients required reoperation (3/33, 9.1%). Two underwent extension of fusion to the previously decompressed adjacent level (2/33, 6.1%), while one underwent revision at the initially instrumented level. These are observed proportions over the reported follow-up, not comparative estimates of risk reduction.
Four patients experienced perioperative complications (12.1%): one CSF leak, one hardware failure, one wound dehiscence and one wound infection. No neurological complications were reported. Mean operative duration was 213.7 minutes, and median hospital stay was 48 hours. Blood loss was recorded in the categories below 50 mL or 50-150 mL in 28 of 33 patients.
Fusion was reported in 25 of the 26 patients with complete imaging (96.2%). Cage subsidence was present in six of these patients at the latest radiographic assessment (23.1%). Disc height and segmental lordosis improved; mean segmental lordosis increased from 14.1 degrees preoperatively to 17.4 degrees immediately after surgery and measured 16.4 degrees at final radiographic follow-up.
Pain and disability scores also improved. Median leg-pain VAS decreased from 5.5 before surgery to 0 at final follow-up. The final mean back-pain VAS was 3.1, compared with a preoperative median of 7.0. Final median ODI was 13.5, compared with a preoperative mean of 42.1. Because the paper reports a mixture of means and medians, these figures should not be subtracted and presented as a uniform average treatment effect.
Interpretation
The most useful surgical distinction is between adjacent stenosis and adjacent instability. This approach does not simply abbreviate a multilevel fusion: it assigns different treatments to levels with different mechanical requirements. The index level receives stabilization, while the adjacent level remains unfused only when it is radiographically stable and suitable for ULBD.
Preservation of the adjacent facets and posterior tension band is central to the rationale. A limited decompression designed to retain these structures cannot be considered mechanically interchangeable with a wide adjacent-level laminectomy. The authors distinguish this indication from bisegmental instability or foraminal stenosis requiring substantial facetectomy, situations in which a two-level fusion may address a different problem. The series does not validate a universal imaging threshold for selecting decompression alone.
The expandable cage introduces a separate technical consideration. The discussion emphasizes endplate preservation and controlled expansion, and the observed subsidence rate warrants attention even in the presence of a high reported fusion rate. Neither these data nor the accompanying illustration establish superiority of a particular cage design or an optimal expansion protocol.
The principal contribution is evidence of feasibility and early durability in a selected cohort. Two adjacent-level fusion extensions over a median of approximately two years are encouraging, but they do not demonstrate prevention of adjacent segment disease. The authors themselves caution that institutional single-level and two-level fusion series had different indications and follow-up periods and are contextual references rather than valid control groups.
Limitations
The study is small, retrospective and confined to one highly experienced surgeon, without a comparative control group. Selection limits applicability to patients with instability at more than one level, high-grade spondylolisthesis, epidural fibrosis or advanced osteoporosis. Seven patients lacked complete serial imaging, and fusion was not routinely confirmed with CT. Clinical and radiographic follow-up durations differ substantially, and the longer-term risk of adjacent-level deterioration remains uncertain. Absence of neurological complications in 33 patients cannot establish a negligible risk. Comparative advantages in morbidity, reoperation or motion preservation remain unproven.
Clinical takeaway
Consider selective fusion as a question of segment-specific pathology: stabilize the level that requires it and assess whether an adjacent stable stenotic level can be adequately decompressed while preserving its supporting structures. This series supports discussing one-and-a-half MIS-TLIF as an option in appropriately selected patients, with explicit counseling about possible later fusion extension. It does not support substituting limited decompression for fusion at a second genuinely unstable segment.