Disclosures: Karthikeyan Bhuvaneswaran, DO: No financial relationships or conflicts of interest

Objective: To demonstrate the feasibility of obtaining quantitative, comparative measures of sensorimotor function across individuals with varying outcomes from chronic tendon transfers and within individuals as they relearn muscle function following a tendon transfer.

Design: Protocol involved passive elbow manipulandum (joint proprioception in flexion/extension) using specifically designed apparatus, Surface EMG to analyze synergistic muscle activation and reflex testing (tendon tap, vibratory, H-Reflex and withdrawal) using surface EMG. Setting : Patients were evaluated in the outpatient clinic setting. Participants : Patients with C5/C6 level spinal cord injuries who have undergone at least one biceps to triceps transfer surgeries.

Interventions: None. This study aims to observe the findings related to return of voluntary control and reflex functions after tendon transfer in SCI patients.

Main Outcome Measures: Intact joint proprioception in elbow flexion/extension, synergistic muscle activation based on EMG recordings of the various muscles (biceps, brachioradialis, triceps, and posterior deltoid) and isometric contraction, preservation of tendon reflexes and withdrawal reflex based on EMG recordings.

Results: Patient A – showed weak elbow flexion clinically (MMT 2, no extension against gravity). This participant showed no biceps activity during extension; the movements were performed via external rotation using the deltoid. However, biceps activity was present during repeated flexion, along with its synergistic muscles (Brachialis and brachioradialis). Patient B – showed elbow flexion (4/5) and extension (3/5). Also showed marked biceps activity during fast extension. Surprisingly, a tendon tap on the transferred biceps tendon showed a large clinical flexion reflex, mediated in large part by the brachialis. Thus, despite relearning voluntary control of the biceps as an extensor, the heteronymous spinal tendon reflex still responded as it would before the transfer. Conclusions: Although the patients had identical tendon transfer procedures, outcomes from the study were variable. Our findings indicate more data is needed to formulate standardized rehabilitation therapies to ensure optimal functional outcomes following tendon transfers in all candidates.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/a-pilot-study-investigating-return-of-voluntary-and-reflexive-function-in-c5-c6-spinal-cord-injury-patients-who-underwent-biceps-to-triceps-tendon-transfer/