Selective denervation of the levator scapulae muscle: an amendment to the Bertrand procedure for the treatment of spasmodic torticollis

Abstract

The purpose of this cadaveric study was to explore a modification to the Bertrand procedure for the treatment of spasmodic torticollis, namely the denervation of the levator scapulae (LS) muscle for laterocollis. The authors performed a series of 9 cadaveric dissections. Five were done to identify the anterior innervation of the LS, and the remaining 4 were to identify the tendinous insertions of the LS onto the lateral masses of the cervical spine via a posterior approach. The nerve supply to the LS from the anterior divisions of the C-3 and C-4 nerve roots and the contribution from the dorsal scapular nerve were identified over the anterior surface of the muscle. The C-3 and C-4 nerve root branches were situated within 2 cm of each other and inferior to the punctum nervosum. The dorsal scapular contribution was clearly identified in 2 cadavers. Selective denervation of this muscle is possible through the same posterior triangle incision used for denervating the sternocleidomastoid muscle of its accessory nerve branches. This approach will be helpful in patients with laterocollis contralateral to the direction of chin turning. The authors compare this approach to the posterior approach for sectioning the insertions of the LS muscle onto the C1-4 posterior tubercles. The latter approach is appropriate for ipsilateral laterocollis. The posterior triangle approach for denervating the LS muscle is a safe and easy addition to the Bertrand procedure and can be helpful in selected cases of torticollis with a laterocollis component.