Assessing Global Upper Extremity Function Before and After Decompressive Surgery in Patients With Degenerative Cervical Myelopathy (DCM).

STUDY DESIGN: A total of 20 patients with degenerative cervical myelopathy (DCM) and a plan for surgical decompression were recruited in this pilot study to assess a new outcome measure. Patients were evaluated preoperatively and 3 months, 6 months, and 1 year postoperatively using a 3-dimensional motion-tracking application (reachable workspace) to calculate an upper extremity (UE) relative surface area (RSA) and standard measurements [modified Japanese Orthopedic Association (mJOA), 12-Item Short Form Health Survey (SF-12), and visual analog pain (VAP) score]. Baseline demographic data were collected. OBJECTIVE: To assess the validity and comparativeness of a new measurement tool in DCM. SUMMARY OF BACKGROUND DATA: Currently, no universally accepted outcome measure exists for DCM. Traditionally used assessment scales are subjective and lack sensitivity. The reachable workspace, a graphical representation of UE spatial surface area using motion-sensor technology, can be used as an objective adjuvant assessment tool in DCM. METHODS: The Welch t test was performed to assess UE RSA differences between DCM patients and healthy controls (HC). Concurrent validity and effect size of the RSA were compared to the standard measurements. A P=0.05 was accepted as statistically significant. RESULTS: DCM patients had significantly reduced RSA of all quadrants compared to controls, with the largest reductions in the upper quadrants (P<0.0001). Total RSA was significantly associated with total mJOA score (ρ=0.48, P<0.0001), upper extremity mJOA score (ρ=0.44, P<0.0002), VAP score during movement (ρ=-0.40, P<0.0007), and the SF-12 mental component (ρ=0.34, P<0.005). Patients with symptoms <1 year before surgery showed improved function via significant increases in total RSA and mJOA score. A stronger effect size was seen with RSA. CONCLUSION: The reachable workspace shows potential to track DCM UE function with accuracy, reliability, and sensitivity to change. Given the promise of this pilot study, a larger study to increase power and substantiate our results will be performed in the future.