Introduction
Studies have identified Magnetic Resonance Imaging proxies (MRIPs) that are associated with radiologic lumbar segmental instability. These include presence of facet joint effusion, sagittal orientation of the facet joints and preserved disc height.
The purpose of this study was to investigate if patient reported outcome measures (PROMs) at five-years after surgery are associated with the presence of preoperative MRIPs for segmental instability in patients with lumbar spinal stenosis (LSS) treated with decompression alone.
Methods
Retrospective cohort study. We included Danish and Swedish patients from two major spine centers with LSS at L4/L5 undergoing primary decompression surgery from 2010-2017. Further inclusion criteria were preoperative supine MRI showing no slip on MRI, enrollment in the Danish or Swedish national spine surgical database with five-year follow-up. MRIPs defined as presence of facet effusion ≥ 1mm, facet angle ≥ 46º and disc height index ≥13 %. Patients were divided into two groups based upon absence (MRIP(-)) or presence (MRIP(+)) of MRIPs and propensity matched. Changes in Patient Reported Outcomes (PROs) ODI, EuroQol-5D, VAS back and leg baseline, one-, two- and five-year post-operative were analyzed using repeated measures ANOVA.
Results
104 patients met inclusion criteria, 83 MRIP(-) and 21 MRIP(+). Propensity matching resulted in 21 in each group. Patients in both groups showed significant improvement in all PROMs post-operative. Improvements in ODI, VAS back pain and EuroQOL-5D were similar between the two groups. Patients in MRIP(+) group had statistically significant worse VAS leg scores at five years (38.8) compared to MRIP(-) (13.13) p=0.024.
Discussion
In patients with LSS and without slip, presence of MRIPs for segmental instability preoperatively. Does not affect ODI or EuroQOL-5D, back pain. 5 years after decompression only surgery. However, presence of MRIPs may be associated with less improvement in leg pain.