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Decompression Surgery Alone Versus Decompression Plus Fusion in Symptomatic Lumbar Spinal Stenosis

A Swiss Prospective Multicenter Cohort Study With 3 Years of Follow-up

Ulrich, Nils H., MD; Burgstaller, Jakob M., MD, DMD; Pichierri, Giuseppe, PhD; Wertli, Maria M., MD, PhD†,‡; Farshad, Mazda, MD, MPH§; Porchet, François, MD; Steurer, Johann, MD; Held, Ulrike, PhD; on behalf of the LSOS Study Group

doi: 10.1097/BRS.0000000000002068

Study Design. Retrospective analysis of a prospective, multicenter cohort study.

Objective. To estimate the added effect of surgical fusion as compared to decompression surgery alone in symptomatic lumbar spinal stenosis patients with spondylolisthesis.

Summary of Background Data. The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial.

Methods. Patients of the Lumbar Stenosis Outcome Study with confirmed DLSS and spondylolisthesis were enrolled in this study. The outcomes of this study were Spinal Stenosis Measure (SSM) symptoms (score range 1–5, best-worst) and function (1–4) over time, measured at baseline, 6, 12, 24, and 36 months follow-up. In order to quantify the effect of fusion surgery as compared to decompression alone and number of decompressed levels, we used mixed effects models and accounted for the repeated observations in main outcomes (SSM symptoms and SSM function) over time. In addition to individual patients’ random effects, we also fitted random slopes for follow-up time points and compared these two approaches with Akaike's Information Criterion and the chi-square test. Confounders were adjusted with fixed effects for age, sex, body mass index, diabetes, Cumulative Illness Rating Scale musculoskeletal disorders, and duration of symptoms.

Results. One hundred thirty-one patients undergoing decompression surgery alone (n = 85) or decompression with fusion surgery (n = 46) were included in this study. In the multiple mixed effects model the adjusted effect of fusion compared with decompression alone surgery on SSM symptoms was 0.06 (95% confidence interval: −0.16–0.27) and −0.07 (95% confidence interval: −0.25–0.10) on SSM function, respectively.

Conclusion. Among the patients with degenerative lumbar spinal stenosis and spondylolisthesis our study confirms that in the two groups, decompression alone and decompression with fusion, patients distinctively benefited from surgical treatment. When adjusted for confounders, fusion surgery was not associated with a more favorable outcome in both SSM scores as compared to decompression alone surgery.

Level of Evidence: 3

Department of Orthopedics and Neurosurgery, Spine Center, Schulthess Clinic, Zurich, Switzerland

Horten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich, Zurich, Switzerland

Division of General Internal Medicine, Bern University Hospital, Bern University, Bern, Switzerland

§Spine Division, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.

Address correspondence and reprint requests to Nils H. Ulrich, MD, Department of Orthopedics and Neurosurgery, Spine Center, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland; E-mail:

Received 7 October, 2016

Revised 30 November, 2016

Accepted 5 December, 2016

Drs Ulrich and Burgstaller have contributed equally to this work.

The manuscript submitted does not contain information about medical device(s)/drug(s).

The Baugarten Foundation, the Helmut Horten Foundation, the Pfizer-Foundation for geriatrics and research in geriatrics, the Symphasis Charitable Foundation, and the OPO Foundation funds were received in support of this work.

No relevant financial activities outside the submitted work.

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