Predicting Clinically Important Difference in Lumbar Decompression Surgery: The Influence of Demographic, Clinical and Radiographic Characteristics.

Abstract

Lumbar decompression is a common intervention for spinal stenosis and disc herniation, yet many patients fail to achieve a Minimal Clinically Important Difference (MCID) in disability. Identifying predictors of MCID may optimize patient selection and improve surgical outcomes. To identify demographic, clinical, and radiographic predictors of MCID achievement one year after lumbar decompression, and to develop a preoperative risk stratification tool. Prospective cohort study using a single-center spine registry. 190 patients undergoing 1-4 level lumbar decompression (laminectomy, microdiscectomy, or laminotomy) from 2020-2023. Oswestry Disability Index (ODI) improvement meeting MCID, defined as ≥12.8-point improvement or ≥50% improvement if baseline ODI ≤26, per validated thresholds. Patients were grouped by MCID status (MCID+ vs. MCID-). Comparative statistics, ROC analysis, and stepwise logistic regression were used to identify independent preoperative predictors. Mean age was 60.2 years; 64% were male. At one year, mean ODI improved from 41.9 to 16.3 (p < 0.001). Predictors of successful outcomes (MCID+) included: Demographic (age <62.2yrs, CCI <1.5, Clinical (symptom duration <6 months, ODI >41) and Radiographic (sagittal lordosis at L1 <9.67°, pelvic tilt <20.9°, pelvic incidence <54°). Subgroup analyses showed that predictors differed by procedure type, with microdiscectomy outcomes primarily influenced by symptom duration and number of levels decompressed, whereas laminectomy/laminotomy outcomes were additionally associated with segmental lordosis. A 4-point risk score was developed using the four strongest independent predictors overall: symptom duration <6 months, ODI >41, and pelvic tilt <20.9°, and procedure type (microdiscectomy). MCID achievement ranged from 39% (0 predictors) to 100% (4 predictors). Shorter symptom duration, greater baseline disability, favorable pelvic alignment, and procedure type were independently associated with MCID achievement. The overall 4-point, 3-point for laminectomy/laminotomy, and 2-point for microdiscectomy risk scores are a practical tool for individualized preoperative counseling and surgical planning.