Lumbar Spinal Stenosis Associated With Degenerative Lumbar Spondylolisthesis: A Systematic Review and Meta-analysis of Secondary Fusion Rates Following Open vs Minimally Invasive Decompression

Neurosurgery 80:355–367, 2017

Decompression without fusion is a treatment option in patients with lumbar spinal stenosis (LSS) associated with stable low-grade degenerative spondylolis- thesis (DS). A minimally invasive unilateral laminotomy (MIL) for “over the top” decom- pression might be a less destabilizing alternative to traditional open laminectomy (OL). OBJECTIVE: To review secondary fusion rates after open vs minimally invasive decom- pression surgery.

METHODS: We performed a literature search in Pubmed/MEDLINE using the keywords “lumbar spondylolisthesis” and “decompression surgery.” All studies that separately reported the outcome of patients with LSS+DS that were treated by OL or MIL (transmuscular or subperiosteal route)were included in our systematic review and meta-analysis. The primary end point was secondary fusion rate. Secondary end points were total reoperation rate, postoperative progression of listhetic slip, and patient satisfaction.

RESULTS: We identified 37 studies (19 with OL, 18 with MIL), with a total of 1156 patients, that were published between 1983 and 2015. The studies’evidence was mostly level 3 or 4. Secondary fusion rates were 12.8% after OL and 3.3% after MIL; the total reoperation rates were 16.3% after OL and 5.8% after MIL. In the OL cohort, 72% of the studies reported a slip progression compared to 0% in the MIL cohort, respectively. After OL, satisfactory outcome was 62.7% compared to 76% after MIL.

CONCLUSION: In patients with LSS and DS, minimally invasive decompression is associated with lower reoperation and fusion rates, less slip progression, and greater patient satisfaction than open surgery.

 

Comparison of Superior-Level Facet Joint Violations During Open and Percutaneous Pedicle Screw Placement

Neurosurgery 71:962–970, 2012 

Superior-level facet joint violation by pedicle screws may result in increased stress to the level above the instrumentation and may contribute to adjacent segment disease. Previous studies have evaluated facet joint violations in open or percutaneous screw cases, but there are no reports describing a direct institutional comparison.

OBJECTIVE: To compare the incidence of superior-level facet violation for open vs percutaneous pedicle screws and to evaluate patient and surgical factors that affect this outcome.

METHODS: We reviewed 279 consecutive patients who underwent an index instrumented lumbar fusion from 2007 to 2011 for degenerative spine disease with stenosis with or without spondylolisthesis. We used a computed tomography grading system that represents progressively increasing grades of facet joint violation. Patient and surgical factors were evaluated to determine their impact on facet violation.

RESULTS: Our cohort consisted of 126 open and 153 percutaneous cases. Percutaneous procedures had a higher overall violation grade (P = .02) and a greater incidence of high-grade violations (P = .006) compared with open procedures. Bivariate analysis showed significantly greater violations in percutaneous cases for age,65 years, obesity, pedicle screws at L4, and 1- and 2-level surgeries. Multivariate analysis showed the percutaneous approach and depth of the spine to be independent risk factors for highgrade violations.

CONCLUSION: This study demonstrates greater facet violations for percutaneously placed pedicle screws compared with open screws.