Results of Phrenic Nerve Transfer to the Musculocutaneous Nerve Using Video-Assisted Thoracoscopy in Patients with Traumatic Brachial Plexus Injury: Series of 28 Cases

Abstract

BACKGROUND The phrenic nerve can be transferred to the musculocutaneous nerve using video-assisted thoracoscopy, aiming at the recovery of elbow flexion in patients with traumatic brachial plexus injuries. There are few scientific papers in the literature that evaluate the results of this operative technique. OBJECTIVE To evaluate biceps strength and pulmonary function after the transfer of the phrenic nerve to the musculocutaneous nerve using video-assisted thoracoscopy. METHODS A retrospective study was carried out in a sample composed of 28 patients who were victims of traumatic injury to the brachial plexus from 2008 to 2013. Muscle strength was graded using the British Medical Research Council (BMRC) scale and pulmonary function through spirometry. Statistical tests, with significance level of 5%, were used. RESULTS In total, 74.1% of the patients had biceps strength greater than or equal to M3. All patients had a decrease in forced vital capacity and forced expiratory volume in 1 s, with no evidence of recovery over time. CONCLUSION Transferring the phrenic nerve to the musculocutaneous nerve using video-assisted thoracoscopy may lead to an increase in biceps strength to BMRC M3 or greater in most patients. Considering the deterioration in the parameters of spirometry observed in our patients and the future effects of aging in the respiratory system, it is not possible at the moment to guarantee the safety of this operative technique in the long term.

Biceps Activity Synchronous with Inspiration After Phrenic Nerve Transfer

“…Phrenic nerve transfer to musculocutaneous nerve is a promising option in traumatic brachial plexus injury for restoration of elbow flexion in selected patients 1 . There was improvement in biceps power to MRC grade ≥ 3 in about 74% of the patients after a mean duration of 38 months following the surgery in a study 2 . Breathing has a considerable impact on elbow function after nerve transfer for elbow function reconstruction both clinically and electromyographically 3 .…”

“…1 There was improvement in biceps power to MRC grade ≥ 3 in about 74% of the patients after a mean duration of 38 months following the surgery in a study. 2 Breathing has a considerable impact on elbow function after nerve transfer for elbow function reconstruction both clinically and electromyographically. 3 The return of muscle power takes some time after surgery, but EMG can aid in early assessment by looking for MUAPs in biceps, which appear synchronous with inspiration.…”

Transfer of Soleus Muscular Branch of Tibial Nerve to Deep Fibular Nerve to Repair Foot Drop After Common Peroneal Nerve Injury: A Retrospective Study

“…BMRC grading was used to evaluate ankle dorsiflexion strength preoperatively. The BMRC grading system rates muscle strength on a scale of M0 (no muscle contraction) to M5 (normal muscle contraction against full resistance) (22). At the time of preoperative evaluation, all patients were graded M0.…”

“…Muscle strength was evaluated again with the BMRC grading system. The results of the nerve transfer were categorized as poor when muscle strength was judged to be grade M2 or less and as good when the muscle strength was graded M3 or M4 (22). EMG recordings were used to assess CPN and tibial nerve function and the muscles they innervate 1 year after nerve-transfer surgery.…”

“…Taken together, these findings prompted us to develop a new strategy for the management of CPN-related foot drop through nerve transfer. Specifically, we used the soleus muscular branch of the tibial nerve as the donor for the deep fibular nerve after CPN injury, and then evaluated functional outcomes using the BMRC muscle strength grading system (22) and EMG.…”