Ultrasonic Evaluation of Muscle Recovery Following Free Functioning Gracilis Transfer, A Preliminary Study
Background: Ultrasonic measurement has not been utilized to assess functional recovery of transplanted muscle. This study aimed to investigate the feasibility of B-ultrasound measurement for evaluation of muscle recovery following free functioning gracilis transfer.Methods: From January 2009 to January 2014, 35 patients receiving free functioning gracilis transfer due to total brachial plexus injury were enrolled. B-ultrasound was utilized to measure the cross-sectional area (CSA) of
... (CSA) of transplanted gracilis muscle at rest and contraction state. The ratio of pre- to post-transplant CSA value at rest state was defined as muscle bulk ratio (MBR). The ratio of CSA value at the contraction state to that at rest state was defined as contraction ratio (CR). Results: Patients with muscle strength M≥4 had significantly higher CR1 (post-transplant), CR2 (pre-transplant), and range of motion (ROM, joint mobility) than those with muscle strength M<4. The CR1>CR2 group had significantly higher CR1, muscle strength, and ROM than the CR1≤CR2 group. The MBR>1 group had significantly higher muscle strength than the MBR≤1 group. CR1 value was highly correlated with muscle strength and with ROM. CR2 value was moderately correlated with muscle strength and ROM. Multivariate linear regression analysis showed that higher CR1/CR2 value was associated with higher muscle strength and higher joint mobility. The CR1>CR2 group had better muscle strength and ROM than the CR1≤CR2 groups.Conclusion: B-ultrasound measurement can quantitatively reflect muscle strength following gracilis transfer, and CR but not MBR value could be a potential indicator for functional recovery of the transplanted gracilis muscle.Level of Evidence: Prognostic studies, Level II.