Phrenic nerve transfer in brachial plexus injury

A retrospective comparative study of 42 patients comparing phrenic nerve transfer (PNT; n=19) against PNT with multiple intercostal nerve transfer (PNT+MIT; n=23) reported that a certain degree of hemidiaphragm elevation (a mean of 1 to 1.5 intercostal spaces) was observed in 90% (38 out of 42) of patients at a mean follow-up of 10 years. Diaphragmatic excursion was reduced by a mean of 0.5 to 1 intercostal spaces in both the groups after the procedures. Hemidiaphragm elevation and movement reduction did not worsen as the number of intercostal nerves used increased from 2 to 4 in the PNT+MIT group, or if both procedures were done at the same stage or performed at an interval of 1 to 2 months.

A case series of 19 patients treated by PNT+MIT reported persistent ipsilateral diaphragmatic paralysis in all patients for up to 36 months (p<0.01).

The quasi-randomised study of 36 patients comparing PNT (n=17) against intercostal nerve transfer (n=19) reported that pulmonary function (forced vital capacity, forced expiratory volume in 1 second, vital capacity and tidal volume) was significantly lower in the PNT group than in the intercostal nerve transfer group throughout 1 year of follow-up. Body position had a significant effect on forced vital capacity in the PNT group but no effect in the intercostal nerve transfer group.

The retrospective case series of 180 patients of whom 65 patients were followed up for more than 2 years reported that pulmonary function tests in 19 patients (including forced vital capacity, total lung capacity, functional residual capacity, vital capacity and maximum ventilation volume) showed decreased pulmonary function during the first year after PNT surgery, improving to normal values by 2 years.

The case series of 19 patients who had PNT+MIT reported mild dyspnoea on exertion in 42% (8 out of 19) of patients at 6-month follow-up (p<0.05), which resolved by 1-year follow-up.

The specialist advisers listed theoretical adverse events as chest wall deformity, herniation, basal atelectasis or collapse, poor voluntary control of muscles innervated by the transfer and failure to re-innervate target muscles due to proximal injury to the phrenic nerve.