Principal Investigators: Wendy M. Murray, PhD and Vincent R. Hentz, MD Project Staff: Feliz E. Zajac, PhD; M. Elise. Johanson, MS, PT; Joe Towles, MS; and Niels Smaby, MS Project Category: Spinal Cord Injury Objective: This project aims to establish specific, objective procedural guidelines for determining the length at which donor muscles in tendon transfer surgeries should be set to best restore function. The brachioradialis is often used as a donor muscle for tendon transfers that restore wrist and hand function after tetraplegia. Restored function often depends on elbow position, wrist position, and thumb posture after brachioradialis transfers. There is evidence that intra-operative surgical tensioning is the critical factor that determines in what joint postures the transferred muscle is strongest. We hypothesize that the functional outcomes of brachioradialis tendon transfers can be improved by optimizing intra-operative surgical tensioning. Research Plan: During this project period, we will complete biomechanical computer simulations of two common brachioradialis transfers, quantify current surgical techniques using a laser diffraction device to measure muscle sarcomere lengths intra-operatively, and implement innovative, scientific-based tools to test hand impairment and function before and after brachioradialis transfers. These tests will detail how the three basic elements of grasping (pinch force magnitude, pinch force direction, and grasp opening) are linked to surgical tensioning. Work Accomplished: The laser device has been transferred to the VA Palo Alto, and has been implemented intra-operatively in three patients to measure muscle sarcomere lengths during tendon transfer surgery. A database has been created that identifies patients who have undergone brachioradialis tendon transfers at the VA Palo Alto HCS and are eligible to participate in this study. Patient testing has begun, and analysis of the data is ongoing. Significant progress on the integrated upper extremity model has been achieved. Expected Outcome: This project will determine the relationship between surgical tensioning and post-operative hand impairment and function, and will propose a specific approach to surgical tensioning of brachioradialis transfers that will improve surgical outcomes. Funding Source: VA RR&D Merit Review Funding Status: Funded |
