Surgical anatomy of the platysma motor branch as a donor for transfer in brachial plexus repair.
OBJECTIVE
Nerve transfers have become a major weapon in the battle against brachial plexus lesions. Recently, a case involving the successful use of the platysma motor branch to re-innervate the pectoralis major muscle was reported. The present anatomical study was conducted to clarify the surgical anatomy of the platysma motor nerve, in view of its potential use as a donor for transfer.


METHODS
Microsurgical dissections of the facial nerve and its terminal branches were performed bilaterally in five formaldehyde-fixed cadavers, thereby yielding ten samples for study. The relationships between the platysma motor branch and adjacent structures were studied and measurements performed. Specimens were removed and histologically studied.


RESULTS
The platysma branch of the facial nerve was found to arise from the cervicofacial trunk. In five instances, one main nerve innervated the platysma muscle, and there was a smaller accessory nerve; in four cases, there was just a single branch to the muscle; and in one case, there was a main branch and two accessory branches. The distance between the gonion and the platysma motor branch averaged 0.8 cm (range 0.4-1.1 cm). The platysma branch received thin anastomotic rami from the transverse superficial cervical plexus. The neural surface of the platysma motor branch, on average, was 76% the surface area of the medial pectoral nerve.


CONCLUSIONS
The anatomy of the platysma motor branch is predictable. Contraction of the platysma muscle is under voluntary control, which is an important quality for a donor nerve selected for transfer. The clinical usefulness of platysma motor branch transfer still must be elucidated.
Peripheral Nerve Section, Department of Neurosurgery, Hospital de Clínicas, University of Buenos Aires, Buenos Aires, Argentina. socolovsky@fibertel.com.ar
Mariano Pablo
MP
Socolovsky
Jayme Augusto
JA
Bertelli
Gilda Di
GD
Masi
Alvaro
A
Campero
Lucas
L
Garategui
Horacio
H
Conesa
Marcos Flávio
MF
Ghizoni
D001917:Brachial Plexus / Q000601:surgery*; D002102:Cadaver; D002572:Cervical Plexus / Q000033:anatomy & histology; D005154:Facial Nerve / Q000033:anatomy & histology*; D006801:Humans; D009334:Neck Muscles / Q000294:innervation*; D016067:Nerve Transfer