Study design: Prospective.
Objective: To evaluate improvements in grip and pinch strength in patients with or without myelopathy and determine patient factors that are predictive of continued postoperative grip strength weakness.
Summary of background data: The degree to which cervical myelopathy can diminish upper extremity muscle strength has not been objectively characterized. Few studies have investigated the association between the expected improvements in patient-reported outcomes (PROs) and strength in grip and pinch after anterior cervical discectomy and fusion (ACDF).
Methods: Patients were asked to perform grip and pinch strength tests both preoperatively and at 6-month follow-up. Patients were also administered PRO surveys, which included Neck Disability Index, Short-Form-12 physical composite score and mental composite score, and Visual Analog Scale neck and arm pain scores. Receiver operating characteristic (ROC) curve analysis was used to determine optimum cutoff values of preoperative patient factors to predict postoperative dominant handgrip weakness after ACDF.
Results: Patients with radiculopathy demonstrated a significantly greater improvement in Visual Analog Scale arm pain compared with patients with myelopathy. The ROC curve analysis determined the optimum cutoff for preoperative dominant handgrip strength to be 22 kgf. This value demonstrated a sensitivity of 0.89 and a specificity of 0.62. The area under the ROC curve value was 0.71 (95% confidence interval, 0.55-0.88), indicating fair prognostic accuracy of the cutoff for postoperative dominant handgrip weakness.
Conclusions: In this prospective, observational study, postoperative increase in grip and pinch strength demonstrated an association with improvement of pain and disability of the neck and overall quality of health regardless of the presence of cervical myelopathy. Preoperative grip strength weakness was found to be predictive of postoperative grip strength deficiency after ACDF. Our investigation suggests the recovery of hand function may be correlated with improvement of PROs after ACDF.