Spinopelvic alignment should influence treatment option of grade I degenerative spondylolisthesis and stenosis

David Casper

Lumbar laminectomy with fusion is superior to laminectomy alone in terms of health-related quality of life and reoperation rate at two years postoperatively for patients with sagittal malalignment, represented by high pelvic incidence minus lumbar lordosis (PILL) mismatch, new research, published by David Casper (University of Pennsylvania, Philadelphia, USA) et al in The Spine Journal, has shown.

It was also found that the addition of fusion for patients with low-grade spondylolisthesis, spinal stenosis, and spinopelvic harmony (low PILL mismatch) resulted in worse quality of life outcomes and reoperation rates.

The study, a retrospective sub-group analysis of observational, prospectively collected data, assessed two-year clinical outcomes and one-year patient reported outcomes following laminectomy with concomitant fusion versus laminectomy alone for management of grade I degenerative spondylolisthesis and stenosis.

According to the researchers, this is the first study to examine the effect of spinopelvic alignment on patient-reported and clinical outcomes following decompression alone versus decompression with fusion.

A total of 679 patients treated with laminectomy with fusion or laminectomy alone for grade I degenerative spondylolisthesis and comorbid spinal stenosis performed by orthopaedic and neurosurgeons at three medical centres affiliated with a single, tertiary care centre, were included in the study.

The primary outcome was the change in Patient-Reported Outcome Measurement Information System (PROMIS), Global Physical Health (GPH), and Global Mental Health (GMH) scores at baseline and post-operatively at 4–6 and 10–12 months postoperatively.

Secondary outcomes included operative parameters (estimated blood loss and operative time), and two-year clinical outcomes including reoperations, duration of postoperative physical therapy, and discharge disposition.

Radiographs/MRIs assessed stenosis, spondylolisthesis, pelvic incidence, lumbar lordosis, sacral slope, and pelvic tilt. From this data, two cohorts were created based on PILL, denoted as “high” and “low” mismatch.

Patients underwent either decompression or decompression with fusion; propensity score matching (PSM) and coarsened exact matching (CEM) were used to create matched cohorts of “cases” (fusion) and “controls” (decompression).

Binary comparisons used the McNemar test; continuous outcomes used the Wilcoxon rank-sum test. Between-group comparisons of changes in PROMIS, GPH and GMH scores were analysed using mixed-effects models and analyses were conducted separately for patients with high and low PILL mismatch.

Just under half (49.9%) the patients (339) underwent lumbar decompression with fusion, while 50.1% (340) received decompression.

The study found that, in the high PLL mismatch cohort at 10-12 months postoperatively, fusion-treated patients reported improved PROs, including GMH (26.61 vs. 20.75, p<0.0001) and GPH (23.61 vs. 18.13, p<0.0001). They also required fewer months of outpatient physical therapy (1.61 vs. 3.65, p<0.0001) and had lower two-year reoperation rates (12.63% vs. 17.89%, p=0.0442) compared to decompression-only patients.

In contrast, in the low PLL mismatch cohort, fusion-treated patients demonstrated worse endpoint PROs (GMH: 18.67 vs. 21.52, p<0.0001; GPH: 16.08 vs. 20.74, p<0.0001). They were also more likely to require skilled nursing/rehabilitation centres (6.86% vs. 0.98%, p=0.0412) and extended outpatient physical therapy (2.47 vs. 1.34 months, p<0.0001) and had higher two-year reoperation rates (25.49% vs. 14.71%, p=0.0152).

Speaking to Spinal News International, Casper said: “Looking at current trends in spine surgery, I feel that when anterolisthesis is seen on X-rays, surgeons tend to assume a fusion procedure is necessary.  Anterolisthesis does not guarantee instability, and this has been proven with careful analysis of a host of factors specific to the given degenerative spondylolisthesis. That being said alignment is an important factor to consider as well.

“In isolated single or two level degenerative pathology, alignment is often overlooked and this must be carefully scrutinised to help ensure not only the right surgery is recommended, but also the best outcome is achieved. The goal of this manuscript was to help shed a little light on how alignment may potentially play a role in this commonly treated pathology.”


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