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 5711.3 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.

Automated summary

This study aims to establish clinical benchmarks for upper limb functional improvement following cervical spine surgery, including the minimal clinically important difference (MCID) and substantial clinical benefit (SCB). The results showed that the MCID of DASH score was -8 points and the SCB was -18 points, which can be used to evaluate minimal and significant improvement in upper limb function in patients undergoing cervical spine surgery.