Degenerative cervical myelopathy (DCM) is a common neuropathologic status due to degenerative changes to the cervical spine. There are multiple operative techniques available, including anterior cervical discectomy and fusion, anterior cervical corpectomy, laminoplasty, laminectomy and laminectomy with fusion. C5 palsy is the most common complication with incidence of 0-30%, but several other injuries requiring ENT input may occur. Recurrent laryngeal nerve (RLN) injury has been reported with overall incidence of 1.9-2.7%. It had been thought the right RLN would be most at risk as it would cross the operative field on anterior approach, however incidence does not differ on side of approach.
A recent prospective study showed the incidence rates of hoarseness and subclinical laryngoscopic vocal cord paralysis were 8.3% and 15.9%, respectively, at three to seven days and 2.5% and 10.8%, respectively, at three months after surgery.
Compression of the RLN in the endolarynx has been suggested in some studies and adaptions such as endotracheal tube cuff pressure monitoring, periodic release of retractor during anterior approach and intraoperative laryngeal myographic monitoring (reported to detect RLN injury with sensitivity 100% and specificity 87%) have been used. Superior laryngeal nerve injury can occur with a similar incidence, 1.1-1.3%, and thought to have a similar risk to anterior surgical approach as RLN. Hypoglossal nerve injury is extremely rare (incidence <0.01%) but mostly occurred after high cervical spine surgery by anterior approach or C1-2 screw fixation by direct injury. Interestingly it has also occurred during lower laminectomy/laminoplasty and attributed to cervical hyper flexion position or endotracheal tube causing stretch on the nerve. The paper provides a good overview of the most common complications of DCM surgery. RLN injury appears as the most common ENT related complication from anterior approach.