Can 3-month models or observed 3- or 6-month patient-reported outcome measures accurately predict 12-month disability and pain after lumbar decompressive surgery?

introductionMost lumbar decompressive surgery patients experience symptom improvement to 3 months, after which about 13% experience a clinically relevant deterioration. Patient-reported outcome measures (PROMs) are accepted as indicators of clinical outcome, but the earliest timepoint when PROMs stabilise is unknown and few studies have assessed risk factors for symptom deterioration. This study aimed to identify risk factors for symptom deterioration and identify whether 3-month models or observed 3- or 6-month outcomes accurately predict 12-month disability and pain.

methodsThe development cohort included 1096 prospectively collected discectomy or laminectomy cases with or without single-level fusion from 01/01/2008-31/12/2020 at a single centre. Three-month models were developed using baseline clinical variables and 3-month PROM. The primary 12-month outcome was the Oswestry Disability Index (ODI), and secondary outcomes were back and leg pain. Validation was on 364 cases from 01/01/2021-31/12/2022. Predictive accuracy was evaluated by interclass correlation coefficient (ICC) and by area-under-the-curve (AUC) to classify to a minimal clinically important difference (MCID). MCID concordance rates for observed 3-month and 6-month with 12-month PROM were calculated.

resultsThree-month predictors of 12-month disability and pain were condition duration, smoking, diabetes, rheumatic disorder, lower limb arthroplasty, mobility aided, underweight (BMI < 18.5 kg/m

conclusionSymptom deterioration after 3 months is linked to baseline factors. This study demonstrates that 6-month PROM accurately predict individual patient 12-month disability and pain after 1-2 level discectomy or laminectomy. Fusion surgery requires a minimum 12-month PROM follow-up.