The sedimentation sign is associated with spinal stenosis surgical treatment outcomes


A new study has examined the impact of the sedimentation sign on the effect of spinal stenosis surgery. The study, published by Spine, suggests that a positive sedimentation sign is associated with a significantly greater surgical treatment effect in patients with lumbar spinal stenosis.

Despite being one of the most common reasons for surgery in elderly people, “there is a dearth reliable diagnostic tools that give a clear indication” for lumbar spinal stenosis surgery, write Moses and colleagues. The authors carried out their analysis in response to studies have suggested that positive sedimentation sign on magnetic resonance image may be a possible prognostic indicator.

All patients with lumbar spinal stenosis in both the randomized and observational cohorts had imaging-confirmed stenosis, were surgical candidates, and had neurogenic claudication for at least 12 weeks prior to enrolment. Patients were categorised as “mild,” “moderate,” or “severe” according to stenosis severity. Of the 654 patients with lumbar spinal stenosis enrolled in the Spine Patient Outcomes Research Trial (SPORT), complete T2-weighted axial and sagittal digitized images of 115 patients were available for retrospective review. An independent orthopaedic spine surgeon evaluated these deidentified Digital Imaging and Communications in Medicine files for the sedimentation sign.

The authors report that 60% (76/115) of patients were found to have a positive sedimentation sign. Those with a positive sedimentation sign were more likely to have stenosis at L2–L3 (33% vs. 10%; p=0.016) or L3–L4 (76% vs. 51%; p=0.012), and to have severe (72% vs. 33%; p<0.0001) central stenosis (93% vs. 67%; p=0.001) at two or more concurrent levels (57% vs. 18%; p=0.01). In multivariate models, the surgical treatment effect was significantly larger in the positive sedimentation sign group for Oswestry Disability Index (−16 vs. −7; p=0.02).

Moses et al thus suggest that “A positive sedimentation sign was associated with a small but significantly greater surgical treatment effect for Oswestry Disability Index in patients with symptomatic lumbar spinal stenosis, after adjusting for other demographic and imaging features.” The group’s findings may help surgeons decide on which patients should undergo surgical treatment for lumbar spinal stenosis, and how significant its impacts will be.