Transfer of the First Intercostal Nerve to Supra- and Infraspinatus Muscles: An Anatomical Study and Report of the First Case

We have assessed the anatomical feasibility of a transfer of the first intercostal nerve to the supra- and infraspinatus muscles and report on the first clinical application. Ten fresh cadavers were dissected for this study. Histomorphometric analysis showed the fascicular surface area of the first intercostal nerve at its origin (0.38 mm²) to be comparable to the suprascapular nerve (0.81 mm²). The first intercostal nerve is usually a pure motor nerve. Preservation of the spinal accessory nerve, lack of donor site morbidity and direct suture without nerve graft are the other advantages of this transfer. Its principal indication is in lesions of the upper brachial plexus, used in association with neurotisation of two other intercostal nerves to the anterior branch of the axillary nerve. At 21 months follow-up there was useful motor reinnervation in the first clinical case.