Risk Factors for Failing to Reach a Minimal Clinically Important Difference Following Minimally Invasive Lumbar Decompression.

Abstract

Clinically important postoperative changes can be best evaluated through the minimal clinically important difference (MCID). Our study aims to evaluate risk factors associated with failure to achieve MCID following lumbar decompression (LD). Demographics, perioperative characteristics, and patient-reported outcome measures (PROM) for pain, disability, and physical function were retrospectively reviewed and collected for patients undergoing LD. MCID achievement was calculated using established values. Relative risk of demographic and perioperative characteristics with failure to meet MCID for all PROMs was calculated. Least absolute shrinkage and selection operator (LASSO) was used to estimate individual risk factors, and postestimation logistic regression was performed. The study cohort included 811 patients. Comorbidity burden was associated with failed MCID for visual analog scale (VAS) back and leg pain and Oswestry Disability Index (ODI). Operative levels or duration was associated with failed MCID for VAS leg pain, 12-item short form physical component summary (SF-12 PCS), and the patient-reported outcomes measurement information system physical function (PROMIS PF). Preoperative spinal pathology was associated with failed MCID for VAS leg pain, ODI, SF-12 PCS, and PROMIS PF. Additional risk factors included the type of operation, insurance, age, and body mass index. LASSO selected insurance, age, comorbidity burden, blood loss, operative duration, and type of spinal pathology as significant risk factors for failure to reach MCID. Failure to reach MCID was greatest for VAS back. Age, comorbidity burden, and prolonged procedures were significantly associated with risk for failure to reach MCID for a majority of PROMs. Comorbidity burden combined with operative outcomes may place patients at increased risk for failure to reach MCID for pain, disability, and physical function following LD. Establishes risk factors for failing to reach the threshold of meaningful difference in symptoms after LD surgery.