Late-onset facial nerve degeneration after vestibular schwannoma surgery: incidence, putative mechanisms, and prevention

Abstract

<jats:p>Delayed facial nerve dysfunction after vestibular schwannoma surgery is a poorly understood phenomenon that has been reported to occur in 15 to 29% of patients undergoing microsurgery. It is a condition characterized by spontaneous deterioration of facial nerve function in a patient who has otherwise normal or near-normal facial function in the immediate postoperative period. This delayed paralysis is generally reported to occur in the first few days postsurgery, with the majority of patients eventually recovering their immediate postoperative facial function. However, infrequently, it can also occur more than 1 week after surgery (so-called late-onset facial nerve palsy).</jats:p> <jats:p>The authors reviewed facial nerve outcome in 611 patients who underwent microsurgery between 1973 and 1994. The facial nerve was anatomically preserved in 596 patients (97.5%), and 90% of patients had House-Brackmann[6] Grade 1 or 2 function 1 year after surgery. Late-onset facial dysfunction was seen in 13 patients (2.1%). All of these had significant deterioration in facial nerve function between 1 and 4 weeks postoperatively, and all showed improvement by 1 year. In this study, the focus on these patients who developed late-onset facial palsy. The incidence, treatment strategies, and outcomes will be discussed with emphasis on possible pathophysiological mechanisms that contribute to this relatively rare condition.</jats:p>

Recurrent laryngeal nerve monitoring with surface electrodes in pediatric thyroid surgery

“…A review of 16,692 adults undergoing thyroidectomy identified late‐onset palsy of the recurrent laryngeal nerve in 0.1% of cases, occurring after a median of 2.5 weeks (range 0.5–12 weeks), with 68% recovering after 3 months . There have been no proposed mechanisms in the literature for delayed RLN palsy; however, proposed mechanisms for delayed facial nerve palsy include an inflammatory process leading to arterial vasospasm and ischemia or venous congestion . Interestingly, this patient has since been diagnosed with a COL3A1 mutation suggestive of Ehlers‐Danlos syndrome, a connective tissue disorder known to be associated with dysphonia, incoordination, and/or hypotonia of the vocal cords in 38% of patients …”

Late-onset palsy of the recurrent laryngeal nerve after thyroid surgery

“…Late‐onset nerve palsy has been described in other fields of medicine, particularly in neurosurgery. The majority of these observations derive from studies of patients who developed delayed facial nerve palsy after surgery for acoustic neuroma and microvascular decompression surgery for hemifacial spasm. Delayed nerve palsies have also been reported for other cranial nerves.…”

“…Delayed nerve palsies have also been reported for other cranial nerves. In a review of 611 patients who underwent surgery for vestibular schwannoma, 13 (2·1 per cent) were diagnosed with late‐onset facial nerve palsy; remarkably, none of these patients recovered fully during follow‐up. Proposed mechanisms for delayed facial nerve palsy may be relevant to understanding the damage to the RLN.…”

“…Proposed mechanisms for delayed facial nerve palsy may be relevant to understanding the damage to the RLN. Possible explanations include arterial vasospasm caused by an inflammatory process with ischaemia of the nerve, or venous congestion with nerve dysfunction.…”

“…Apart from these early‐onset palsies, a small subset of patients may develop a late‐onset palsy of the RLN, after normal vocal fold function in the immediate postoperative period. Late‐onset palsy of the facial nerve is a rare but well documented phenomenon after surgery for vestibular schwannoma, and late RLN palsy after thyroid surgery has also been reported. The present investigation aimed to study the incidence and outcome of late‐onset RLN palsy, and to identify possible risk factors for this complication.…”