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J Neurosurg Spine. 2019 Apr 26:1-10. doi: 10.3171/2019.2.SPINE181309. [Epub ahead of print]

Outcome of unilateral versus standard open midline approach for bilateral decompression in lumbar spinal stenosis: is "over the top" really better? A Swiss prospective multicenter cohort study.

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1Horten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich.
2Division of General Internal Medicine, Bern University Hospital, Bern University, Bern.
3University Spine Centre Zurich, Balgrist University Hospital, University of Zurich; and.
4Department of Orthopedics and Neurosurgery, Spine Center, Schulthess Clinic, Zurich, Switzerland.


OBJECTIVEIn this retrospective analysis of a prospective multicenter cohort study, the authors assessed which surgical approach, 1) the unilateral laminotomy with bilateral spinal canal decompression (ULBD; also called "over the top") or 2) the standard open bilateral decompression (SOBD), achieves better clinical outcomes in the long-term follow-up. The optimal surgical approach (ULBD vs SOBD) to treat lumbar spinal stenosis remains controversial.METHODSThe main outcomes of this study were changes in a spinal stenosis measure (SSM) symptoms score, SSM function score, and quality of life (sum score of the 3-level version of the EQ-5D tool [EQ-5D-3L]) over time. These outcome parameters were measured at baseline and at 12-, 24-, and 36-month follow-ups. To obtain an unbiased result on the effect of ULBD compared to SOBD the authors used matching techniques relying on propensity scores. The latter were calculated based on a logistic regression model including relevant confounders. Additional outcomes of interest were raw changes in main outcomes and in the Roland and Morris Disability Questionnaire from baseline to 12, 24, and 36 months.RESULTSFor this study, 277 patients met the inclusion criteria. One hundred forty-nine patients were treated by ULBD, and 128 were treated by SOBD. After propensity score matching, 128 patients were left in each group. In the matched cohort, the mean (95% CI) estimated differences between ULBD and SOBD for change in SSM symptoms score from baseline to 12 months were -0.04 (-0.25 to 0.17), to 24 months -0.07 (-0.29 to 0.15), and to 36 months -0.04 (-0.28 to 0.21). For change in SSM function score, the estimated differences from baseline to 12 months were 0.06 (-0.08 to 0.21), to 24 months 0.08 (-0.07 to 0.22), and to 36 months 0.01 (-0.16 to 0.17). Differences in changes between groups in EQ-5D-3L sum scores were estimated to be -0.32 (-4.04 to 3.40), -0.89 (-4.76 to 2.98), and -2.71 (-7.16 to 1.74) from baseline to 12, 24, and 36 months, respectively. None of the group differences between ULBD and SOBD were statistically significant.CONCLUSIONSBoth surgical techniques, ULBD and SOBD, may provide effective treatment options for DLSS patients. The authors further determined that the patient outcome results for the technically more challenging ULBD seem not to be superior to those for the SOBD even after 3 years of follow-up.


CIRS = Cumulative Illness Rating Scale; DLSS = degenerative lumbar spinal stenosis; EQ-5D-3L = 3-level EQ-5D; HADS = Hospital Anxiety and Depression Scale; LSOS = Lumbar Stenosis Outcome Study; MCID = minimal clinically important difference; SMD = standardized mean difference; SOBD = standard open bilateral decompression; SSM = spinal stenosis measure; ULBD = unilateral laminotomy with bilateral spinal canal decompression; decompression; degenerative lumbar spinal stenosis; fusion; laminectomy; laminotomy; lumbar fusion; multicenter; multilevel; surgery


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