Preventable Sternocleidomastoid Muscular Atrophy after Neck Dissection

BACKGROUND Modified radical neck dissection (mRND) [preserving the sternocleidomastoid muscle (SCM) and the spinal accessory nerve] and supraomohyoid neck dissection have become common surgical procedures for treating head and neck cancer. Postoperative severe asymmetry of the neck and severe atrophy of the SCM, however, have been demonstrated. METHODS Using computed tomographic images, cross-sectional areas of the SCMs were measured in 99 patients with carcinoma of the oral cavity who underwent unilateral mRND or supraomohyoid neck dissection. An asymmetry index was used. RESULTS Innervation to the SCM was preserved in 91 patients. The spinal accessory nerve and the innervation were sacrificed in 3 patients; the innervation was repaired in 5 patients. Sacrifice of innervation to the SCM resulted in extremely severe asymmetry. Repair of the innervation prevented severe asymmetry in 40%. Preservation of the innervation prevented severe asymmetry in 75% at the middle portion of the neck and in 56% at the lower portion after mRND. CONCLUSION Preserving innervation to the SCM and gentle handling of the nerve during neck dissection could prevent severe asymmetry after neck dissection.