Multi-Center Trial to Improve Grasp in Tetraplegia

Principal Investigator: Wendy M. Murray, PhD

Co-Principal Investigator: Vincent R. Hentz, MD

Investigators: M. Elise Johanson, MS, PT and Niels Smaby, PhD

Project Category: Spinal Cord Injury - 2005

Objective: For individuals with cervical spinal cord injury, tendon transfer surgery involves releasing the attachment of a muscle under voluntary control (donor length) and re-attaching it to the tendon of a paralyzed muscle, restoring a function lost to paralysis. Choosing the surgical attachment length of the donor muscle, commonly referred to as "tensioning" the transfer, is considered to be one of the most critical steps in performing the procedure. However, the influence of different attachment lengths on functional outcome has never been directly demonstrated in patients. Currently, surgeons choose surgical attachment lengths based on a number of factors, all related to experience and education. This multi-center study aims to exploit the existing variability in surgical approach and demonstrate for the first time the significance of surgical attachment length on post-operative muscle function.

Research Plan: We plan to investigate the influence of surgical approach on outcome with the following hypotheses:

1. Different surgeons performing the same tendon transfer choose different attachment lengths. We will measure sarcomere length intra-operatively using laser diffraction during transfer of brachioradialis to flexor pollicis longus. Surgeons from six spinal cord injury centers will participate in the study.

2. The surgeon's choice of attachment length is correlated to the selected position of the patient's elbow at the time of tendon transfer. The six surgeons in this study report that they position the patient's elbow differently from each other during brachioradialis tendon transfer. We will test whether the choice of attachment length is related to this variable.

3. The surgeon's choice of attachment length determines how pinch force changes with elbow flexion post-operatively. We will quantify lateral pinch fore produced during maximum effort at different elbow positions post-operatively.

Work Accomplished: We were notified that this project received a fundable score in December 2005. We are currently coordinating human subjects approval at the six sites, and we are awaiting funding to initiate this project.

Expected Outcome: This work will provide the first direct evidence that the choice of surgical attachment length affects post-operative muscle function, will form the basis for educating surgeons on the consequences of different surgical techniques, and, ultimately, will improve patient care.

Funding Source: VA RR&D Merit Review

Funding Status: Pending