Development and temporal validation of clinical prediction models for 1-year disability and pain after lumbar decompressive surgery. The Norwich Lumbar Surgery Predictor (development version).

PURPOSE: To identify clinical predictors and build prediction models for 1-year patient-reported outcomes measures (PROMs) after lumbar decompressive surgery for disc herniation or spinal stenosis. METHODS: The study included 1835 cases, with or without additional single-level fusion, from a single centre from 2008 through 2020. General linear models imputed with 37 clinical variables identified 18 significant 1-year PROM predictors for retention in development models. Interaction of surgical indication with each predictor was tested. Temporal validation was conducted at the same centre on cases through 2021. R2 was used to measure goodness-of-fit, and area under curve (AUC) used to measure classification to a satisfactory symptom state (Oswestry Disability Index (ODI) ≤ 22; back or leg pain ≤ 30 out of 100). RESULTS: A total 1228 (67%) had complete data for inclusion in model development. Predictors of ODI were baseline PROMs (ODI, back pain, leg pain), work status, condition duration, previous lumbar operation, multiple-joint osteoarthritis, female, diabetes, current smoker, rheumatic disorder, lower limb arthroplasty, mobility aided, provider status, facet cyst, scoliosis, and age, with BMI significantly associated with stenosis. Temporal validation (n = 188) found the ODI model R2 was 0.29 (95% confidence intervals (CI) 0.18-0.40) and AUC was 0.74 (95% CI 0.67-0.81). Back and leg pain models had lower R2 (0.12-0.14) and AUC (0.68-0.69) values. CONCLUSION: Important PROM predictors are baseline PROMs, specific co-morbidities, work status, condition duration, previous lumbar operation, female, and smoking status. The ODI model predicted the likelihood of achieving a satisfactory state of both disability and pain.

Incidence and risk factors for five-year recurrent disc herniation after primary single-level lumbar discectomy.

To identify the incidence and risk factors for five-year same-site recurrent disc herniation (sRDH) after primary single-level lumbar discectomy. Secondary outcome was the incidence and risk factors for five-year sRDH reoperation. A retrospective study was conducted using prospectively collected data and patient-reported outcome measures, including the Oswestry Disability Index (ODI), between 2008 and 2019. Postoperative sRDH was identified from clinical notes and the centre's MRI database, with all imaging providers in the region checked for missing events. The Kaplan-Meier method was used to calculate five-year sRDH incidence. Cox proportional hazards model was used to identify independent variables predictive of sRDH, with any variable not significant at the p < 0.1 level removed. Hazard ratios (HRs) were calculated with 95% confidence intervals (CIs). Complete baseline data capture was available for 733 of 754 (97.2%) consecutive patients. Median follow-up time for censored patients was 2.2 years (interquartile range (IQR) 1.0 to 5.0). sRDH occurred in 63 patients at a median 0.8 years (IQR 0.5 to 1.7) after surgery. The five-year Kaplan-Meier estimate for sRDH was 12.1% (95% CI 9.5 to 15.4), sRDH reoperation was 7.5% (95% CI 5.5 to 10.2), and any-procedure reoperation was 14.1% (95% CI 11.1 to 17.5). Current smoker (HR 2.12 (95% CI 1.26 to 3.56)) and higher preoperative ODI (HR 1.02 (95% CI 1.00 to 1.03)) were independent risk factors associated with sRDH. Current smoker (HR 2.15 (95% CI 1.12 to 4.09)) was an independent risk factor for sRDH reoperation. This is one of the largest series to date which has identified current smoker and higher preoperative disability as independent risk factors for sRDH. Current smoker was an independent risk factor for sRDH reoperation. These findings are important for spinal surgeons and rehabilitation specialists in risk assessment, consenting patients, and perioperative management.

Meta-analysis identifies Back Pain Questionnaire reliability influenced more by instrument than study design or population.

OBJECTIVE: To assess if predefined variables in study design, instrument type, and patient characteristics account for variance in reported retest reliability for the Oswestry Disability Index (ODI) and Roland-Morris Questionnaire (RMQ). A second aim was a more precise estimate of instrument reliability. STUDY DESIGN AND SETTING: A systematic literature search of MEDLINE, EMBASE, AMED, PsycINFO, and CINAHL was performed from inception to January 2011. Hand search, gray literature, and reference retrieval completed the search. Two blinded reviewers extracted the data. Original authors were contacted for the missing data. A meta-analysis was performed with the intraclass correlation coefficient as the outcome measure. RESULTS: Fifty studies on 31 ODI and 28 RMQ cohorts were retrieved that met the inclusion criteria. Meta-analysis found the ODI more reliable than the RMQ (coefficient, -0.2840; P = 0.009) and lower reliability on increased days to retest (coefficient, -0.0089; P = 0.005) and in low back pain (LBP) with leg pain than LBP only cohorts (coefficient, -0.2194; P = 0.046). The use of a transition item to identify stable patients and percentage of cohort not included at retest were significant only on single variable analysis. CONCLUSION: Study design and population influence the reliability of a given instrument, however, a greater difference in reliability exists between instruments.