Upper-extremity disability in cervical myelopathy: insights from the Disabilities of the Arm, Shoulder, and Hand questionnaire.

BACKGROUND: Assessing upper-extremity function in cervical myelopathy (CM) remains challenging because neurological scores and patient-reported disability do not always align. The Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire may capture day-to-day limitations that are not fully reflected by conventional CM assessments. We evaluated the clinical utility of the DASH in CM and explored factors associated with discordant outcomes between the Japanese Orthopaedic Association (JOA) score and the DASH. METHODS: We retrospectively reviewed 126 patients with CM who subsequently underwent surgery and assessed their preoperative clinical status. Upper-extremity disability was assessed using the DASH score, together with conventional measures including the JOA score, Neck Disability Index (NDI), symptom-related verbal rating scale (VRS), shoulder range of motion (ROM), grip strength, and the 10-s test, and associations between DASH score and conventional assessments were evaluated. A four-quadrant analysis based on the JOA score and DASH score was performed (JOA ≥ 12 and DASH ≥ 30 defined discordance). Patients with good JOA/poor DASH were compared with those with poor JOA/good DASH. Multivariable logistic regression was conducted, and model discrimination was assessed using receiver operating characteristic (ROC) analysis. RESULTS: Across the cohort, DASH scores correlated significantly with the JOA score, NDI, VRS items, shoulder ROM, grip strength, and the 10-s test. Four-quadrant analysis identified 13 patients (10.3%) with discordant outcomes (good JOA score with poor DASH score). Compared with the poor JOA/good DASH group, the good JOA/poor DASH group demonstrated higher NDI% and higher VRS scores, and had lower non-dominant shoulder ROM, while age, sex, body mass index, grip strength, and the 10-s test were not significantly different. In multivariable analysis, higher VRS pain during activity was independently associated with belonging to the good JOA/poor DASH group (odds ratio 5.65, 95% CI 1.46-21.80; p = 0.01), and the model showed excellent discrimination (AUC = 0.94). CONCLUSIONS: In patients with CM, the DASH may capture patient-perceived upper-extremity disability that generally parallels conventional functional measures while also identifying patients with substantial daily-life disability despite relatively preserved neurological status. Activity-related pain was independently associated with these discordant outcomes. Together, these findings support the complementary value of incorporating the DASH alongside conventional neurological assessments to provide a more comprehensive patient-centered evaluation of upper-extremity function.