Characterising patients undergoing surgery for lumbar spinal stenosis associated neurogenic claudication in the UK: what does the British Spinal Registry tell us?

PURPOSE: Surgery for lumbar spinal stenosis (LSS) has a variable outcome with many not returning to pre-condition activity levels. We aimed to explore the (1) baseline characteristics of UK patients undergoing surgery, and (2) association of patient characteristics with a clinically important improvement in the 6-month Oswestry Disability Index (ODI) in a population defined by previously developed LSS criteria. METHODS: We used data from the British Spinal Registry (BSR) (2012-2023). Anonymised data included demographics, patient reported outcome measures (PROMs) (ODI; visual analogue scale (VAS) for back and leg pain); quality of life (EQ-5D)) at baseline, and 6-weeks and 6-months post-surgery, surgical procedure, surgery duration and intra-operative blood loss. We used descriptive and multivariate analyses to estimate the association between variables and the minimum clinically important difference (MCID) (30% improvement from baseline) in 6-month disability (ODI). MCIDs define the smallest benefit of value to patients. We explored differences in baseline values between 6-month responders and the total database, and between primary and revision surgery. RESULTS: In 6801 patients sampled from the BSR the mean age was 70.5 (SD 9.1), 51% (3452/6794) were female, and most were from higher socioeconomic areas (mean Index of Multiple Deprivation rank 84.3, SD 38.8). Preoperatively most had severe disability (ODI 48.7, SD 17.5), moderate leg (VAS 7.0, SD 2.4) and back pain (VAS 6.3, SD 2.5). Proportionally 58% (1160/2008) of the 6-month responders achieved the MCID in ODI. Higher baseline back pain intensity (odds ratio (OR) 0.9, 95%CI 0.9, 0.9), revision surgery (OR 0.5 95%CI 0.3, 0.8), higher 6-week leg pain intensity (OR 0.9, 95%CI 0.8, 1.0) and severe 6-week disability (OR 0.3, 95%CI 0.2, 0.5) reduced the odds of achieving the MCID in 6-month ODI. CONCLUSIONS: Patients undergoing surgery in the UK are severely disabled prior to surgery. The available data suggests that 42% of UK patients do not achieve a clinically important improvement in 6-month disability.