title: A novel method of lengthening the accessory nerve for direct coaptation during nerve repair and nerve transfer procedures.
abstract: OBJECTIVE The accessory nerve is frequently repaired or used for nerve transfer. The length of accessory nerve available is often insufficient or marginal (under tension) for allowing direct coaptation during nerve repair or nerve transfer (neurotization), necessitating an interpositional graft. An attractive maneuver would facilitate lengthening of the accessory nerve for direct coaptation. The aim of the present study was to identify an anatomical method for such lengthening. METHODS In 20 adult cadavers, the C-2 or C-3 connections to the accessory nerve were identified medial to the sternocleidomastoid (SCM) muscle and the anatomy of the accessory nerve/cervical nerve fibers within the SCM was documented. The cervical nerve connections were cut. Lengths of the accessory nerve were measured. Samples of the cut C-2 and C-3 nerves were examined using immunohistochemistry. RESULTS The anatomy and adjacent neural connections within the SCM are complicated. However, after the accessory nerve was "detethered" from within the SCM and following transection, the additional length of the accessory nerve increased from a mean of 6 cm to a mean of 10.5 cm (increase of 4.5 cm) after cutting the C-2 connections, and from a mean of 6 cm to a mean length of 9 cm (increase of 3.5 cm) after cutting the C-3 connections. The additional length of accessory nerve even allowed direct repair of an infraclavicular target (i.e., the proximal musculocutaneous nerve). The cervical nerve connections were shown not to contain motor fibers. CONCLUSIONS An additional length of the accessory nerve made available in the posterior cervical triangle can facilitate direct repair or neurotization procedures, thus eliminating the need for an interpositional nerve graft, decreasing the time/distance for regeneration and potentially improving clinical outcomes.
authors.affiliation: 1Seattle Science Foundation.|2Department of Anatomical Sciences, St. George's University,Grenada.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.affiliation: 3Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Andrés A
authors.initials: AA
authors.lastname: Maldonado
authors.affiliation: 4Department of Pathology, Children's of Alabama, Birmingham, Alabama; and.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Stoves
authors.affiliation: 5Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg,Germany.
authors.forename: Fabian N
authors.initials: FN
authors.lastname: Fries
authors.affiliation: 4Department of Pathology, Children's of Alabama, Birmingham, Alabama; and.
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.affiliation: 2Department of Anatomical Sciences, St. George's University,Grenada.
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.affiliation: 6Swedish Neuroscience Institute, Seattle, Washington.
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Oskouian
authors.affiliation: 3Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
mesh_terms: D000055:Accessory Nerve / Q000033:anatomy & histology / Q000601:surgery* / Q000637:transplantation*; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*
keywords: SCM = sternocleidomastoid; injury; peripheral nerve; posterior triangle; spinal accessory nerve