Pronator teres branch transfer to the anterior interosseous nerve for treating C8T1 brachial plexus avulsion: an anatomic study and case report.

BACKGROUND: The treatment of C8T1 avulsion is challenging for neurosurgeons. Various methods for the restoration of finger flexion are used. However, most of these methods have different disadvantages and cannot restore the full active range of motion of the fingers.

OBJECTIVE: To determine the feasibility of the pronator teres branch transfer to the anterior interosseous nerve with anatomic study and to use this method in 1 case.

METHODS: The upper limbs of 15 fresh cadavers were dissected to identify the main trunk of the median nerve, the pronator teres branch, and the anterior interosseous nerve. The mean number and length of the pronator teres branches were recorded. The anterior interosseous nerve was dissected atraumatically to the most proximal level where the fibers of the anterior interosseous nerve did not mingle with the fibers of the main trunk of the median, which was defined as the atraumatic level of the anterior interosseous nerve. A line joining the most protruding point of the medial condyle and lateral condyle of the humerus was used as a measurement landmark. Pronator teres branch transfer to the anterior interosseous nerve was performed in 1 patient with C8T1 avulsion.

RESULTS: The mean number of the pronator teres branches was 2.37 ± 0.49. The mean length of the pronator teres branches was 9.64 ± 0.71 mm. The mean distance between the point where the pronator teres branches originated and the landmark line was 3.87 ± 0.34 mm. The mean distance between the atraumatic level of the anterior interosseous nerve and the landmark line was -5.46 ± 0.73 mm. Transfer of the pronator teres was used to innervate the anterior interosseous nerve in 1 patient with C8T1 avulsion. When assessed 14 months after the operation, a full active range of motion of the fingers had been restored, and the patient's finger flexor muscles had regained grade 4 power.

CONCLUSION: The pronator teres can be transferred to the anterior interosseous nerve directly at the elbow level. This operation was performed successfully in 1 patient, who exhibited finger flexion recovery.