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

Abstract

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. To assess the validity and comparativeness of a new measurement tool in DCM. 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. 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. 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. 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.