Success and Failure of Minimally Invasive Decompression for Focal Lumbar Spinal Stenosis in Patients With and Without Deformity
Bibliographic record
Abstract
STUDY DESIGN: Observational cohort study. Retrospective review of prospectively collected outcomes data. OBJECTIVE: The purpose of this study was to evaluate the clinical efficacy of minimally invasive (MIS) decompression for focal lumbar spinal stenosis (FLSS) in patients with and without deformity. SUMMARY OF BACKGROUND DATA: MIS, facet-preserving decompression has the potential of offering a significantly less morbid alternative to decompression and fusion in patients with leg dominant symptoms from degenerative spondylolisthesis and/or scoliosis. METHODS: Single surgeon, consecutive series (n=75), evaluated over 5 years. All patients had MIS lumbar laminoplasty (bilateral decompression from a unilateral approach) for FLSS (1-2 level). Patients had leg dominant, claudicant/radicular pain. Patients were divided into 4 groups: (A) stenosis with no deformity, n=22; (B) stenosis with spondylolisthesis only, n=25; (C) stenosis with scoliosis, n=16; and (D) stenosis combined with spondylolisthesis and scoliosis, n=12. The primary clinical outcome measures were the Oswestry Disability Index (ODI) and surgical revision rate. Preoperative and postoperative standing radiographs were assessed. RESULTS: The average age was 68 years (40-89) with a mean time from surgery of 36.5 months (18-68). Average clinical improvement in ODI was 49.5% to 23.9% [mean postoperative follow-up of 31.8 months (24-72): group A=mean of 34.6; B=28.9; C=32.7; D=30 months]. Incidence of preoperative grade I spondylolisthesis was 46%. Spondylolisthesis progression (mean=8.4%) occurred in 9 patients and 2 patients developed spondylolisthesis. Overall revision rate was 10% [repeat decompression alone (n=2) and decompression and fusion (n=6)]. Subgroup analysis of preoperative and postoperative ODI and revision rate revealed (A) 48% to 18.7%, 0%; (B) 48% to 24.6%, 4%; (C) 50.7% to 31.5%; 25%; and (D) 53% to 22%, 25%, respectively. The revision rate for patient with scoliosis (C+D) was significant (P=0.0035) compared with those without. Six of the 8 revised patients had a preoperative lateral (rotatory) listhesis (3 in C and 3 in D). CONCLUSION: MIS decompression alone for leg dominant symptoms is a clinically effective procedure in the majority of patients including those with degenerative spondylolisthesis or scoliosis. However, patients with scoliosis, particularly those with lateral listhesis, have a significantly higher revision rate that needs to be considered in operative decision-making.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".