Figure 1: Gracilis functional free muscle transfer surgery involves transferring the gracilis muscle from the medial thigh to the upper arm to restore function in patients with brachial plexus injuries. The gracilis offers a rich source of vascular and nervous tissue and its transfer results in minimal morbidity and function loss at the donor site.
At Penn Medicine, a multidisciplinary team of surgeons from the Penn Nerve Center are performing gracilis functional free muscle transfers (FFMT) to restore upper extremity movement to patients with brachial plexus injuries (including avulsion, laceration and contusion).
Brachial plexus injuries are typically traumatic in origin and are marked by paralysis and other functional upper extremity deficits. Restoration of shoulder and elbow function is considered a vital necessity for patients with these injuries, and can be achieved if initiated within six to nine months of injury by nerve grafting and nerve transfers (neurotization). For individuals with brachial plexus nerve injuries that exceed this timespan, gracilis FFMT has the potential to restore movement to the shoulder and elbow.
Gracilis FFMT surgery involves transferring the gracilis muscle, located on the medial aspect of the thigh, to the upper arm (Figure 1). The gracilis muscle has the advantages of a rich blood supply and reliable motor innervation, and FFMT surgery involves minimal donor site morbidity and little to no impairment of leg function.
Once transferred to the upper arm, the gracilis has the capacity to mimic the function of the biceps and brachialis muscles. Neurotization and vascular anastomosis of the muscle at the recipient site are achieved through microsurgery. The reported success rate for gracilis FFMT in patients with brachial plexus avulsion is approximately 70%.1
Clinical Case Study
RL, a 28-year-old man, was referred to the Penn Nerve Center for restoration of movement in his paralyzed right arm. Two years prior, RL had a motorcycle accident resulting in spinal injury and complete right brachial plexus avulsion. Following the injury, he had rehabilitative therapy, including range of motion exercises, which maintained flexibility but did not restore function in the right arm. Since direct nerve repair was no longer an option, a functioning gracilis muscle in RL’s left leg and donor nerves that could serve to re-innervate the muscle transfer were selected.
At Penn, gracilis FFMT surgery proceeds in phases and involves coordinated teams of surgeons from Neurosurgery, Orthopaedics and Plastic Surgery. At the start of surgery, neurosurgeons first explored the brachial plexus to identify viable donor nerve sites. The spinal accessory nerve was selected as a functional donor nerve, maintaining several branches to the trapezius muscle to avoid loss of upper shoulder function.
The orthopaedic and plastic surgery teams prepared the recipient site at the upper arm; the gracilis muscle, obturator nerve, blood vessels and a skin paddle were harvested from RL’s left leg. This tissue was then positioned within the recipient site and the gracilis secured via the clavicle and biceps tendons. With the completion of microvascular repair to the arteries and veins, micro-doppler probes were applied to ensure vessel patency and to measure blood flow.
The neurosurgical team then returned to attach the obturator nerve of the gracilis muscle to the donor spinal accessory nerve. After five days in the hospital for observation, RL was discharged home and had an unremarkable recovery. He is currently participating in daily range of motion rehabilitative therapy.