INTRODUCTION: Selection of patients for decompressive surgery for central spinal stenosis is complex. Well defined imaging characteristics have been established, however their clinical application and prognostic value is poorly documented. It is unclear which preoperative MRI characteristics predict the most favorable outcome in terms of pain relief, HRQoL, estimated walking ability, and general satisfaction. The objective was to investigate the relationship between MRI characteristics (minimal dural sac area, multilevel stenosis, and olisthesis) and HRLQoL, functional status and pain at 1‐year follow‐up in decompressive spinal stenosis surgery.
METHODS: Prospective follow‐up cohort study was performed. The study group included 109 consecutive patients with spinal stenosis with and without spondylolisthesis operated on with decompressive laminectomy. Preoperatively and at 1‐year of follow up the patients completed the EQ‐5D, SF‐36, Oswestry disability index, estimated walking distance, VAS leg and back. The cross sectional area of the cauda equina was measured at the disc level from L1 to S1.
RESULTS: The mean dural sac area was 42.6 mm2. Multilevel stenosis was frequent (50% of patients) and 32% had concomitant low grade spondylolisthesis. Mean age was 71.1 years. Patients with small dural sac area had lower leg (p=0.03) and back (p=0.07) pain levels at follow up. Small preoperative dural sac area (mm2) was associated with greater satisfaction with operative outcome and relief of leg (p=0.07) and back pain (p=0.02). Multilevel stenosis (number of levels with stenosis <70mm2) was associated with reduction in leg pain (VAS) at follow up (p=0.04).
DISCUSSION: The absolute parameters of minimal dural sac area and multilevel stenosis are correlated to positive outcome with regards to pain relief and their consistent use can be advocated. Concomitant low grade spondylolisthesis did not affect outcome at 1‐year follow‐up.