Clinically meaningful improvement in disabilities of arm, shoulder, and hand (DASH) following cervical spine surgery

BACKGROUND CONTEXT: Patients with cervical spine disease suffer from upper limb disabil-ity. At present, no clinical benchmarks exist for clinically meaningful change in the upper limb function following cervical spine surgery. PURPOSE: Primary: to establish clinically meaningful metrics; the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) of upper limb functional improvement in patients following cervical spine surgery. Secondary: to identify the prognostic factors of MCID and SCB of upper limb function following cervical spine surgery. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Adult patients >= 18 years of age who underwent cervical spine surgery from 2012 to 2016. OUTCOME MEASURES: Patient-reported outcomes: Neck disability index (NDI) and Disabil-ities of Arm, Shoulder, and Hand (DASH). METHODS: MCID was defined as minimal improvement and SCB as substantial improvement in the DASH score at last follow-up. The anchor-based methods (ROC analyses) defined optimal MCID and SCB thresholds with area under curve (AUC) in discriminating improved vs. non-improved patients. The MCID was also calculated by distribution-based methods: half standard -deviation (0.5-SD) and standard error of the mean (SEM) method. A multivariable logistic regres-sion evaluated the impact of baseline factors in achieving the MCID and SCB in DASH following cervical spine surgery. RESULTS: Between 2012 and 2016, 1,046 patients with average age of 57</n>11.3 years, 53% males, underwent cervical spine surgery. Using the ROC analysis, the threshold for MCID was -8 points with AUC of 0.73 (95% CI: 0.67-0.79) and the SCB was -18 points with AUC of 0.88 (95% confidence interval [CI]: 0.85-0.91). The MCID was -11 points by 0.5-SD and -12 points by SEM-method. On multivariable analysis, patients with myelopathy had lower odds of achieving MCID and SCB, whereas older patients and those with >= 6 months duration of symptoms had lower odds of achieving DASH MCID and SCB respectively. CONCLUSIONS: In patients undergoing cervical spine surgery, MCID of -8 points and SCB of -18 points in DASH improvement may be considered clinically significant. These metrics may enable evaluation of minimal and substantial improvement in the upper extremity function follow-ing cervical spine surgery.(c) 2023 Elsevier Inc. All rights reserved.