Facial reanimation using the hypoglossal nerve and ansa cervicalis: a short-term retrospective analysis of surgical outcomes

Abstract

Background: Transferring the hypoglossal nerve to the facial nerve using an end-to-end method is very effective for improving facial motor function. However, this technique may result in hemitongue atrophy. The ansa cervicalis, which arises from the cervical plexus, is also used for facial reanimation. We retrospectively reviewed cases where facial reanimation was performed using the ansa cervicalis to overcome the shortcomings of existing techniques of hypoglossal nerve transfer.Methods: The records of 15 patients who underwent hypoglossal nerve transfer were retrospectively reviewed. Three methods were used: facial reanimation with hypoglossal nerve transfer (group 1), facial nerve reanimation using the ansa cervicalis (group 2), and sural nerve interposition grafting between the hypoglossal nerve and facial nerve (group 3). In group 1, the ansa cervicalis was coapted to neurotize the distal stump of the hypoglossal nerve in a subset of patients. Clinical outcomes were evaluated using the House-Brackmann (H-B) grading system and Emotrics software.Results: All patients in group 1 (n = 4) achieved H-B grade IV facial function and showed improvements in the oral commissure angle at rest (preoperative vs. postoperative difference, 6.48° ± 0.77°) and while smiling (13.88° ± 2.00°). In groups 2 and 3, the oral commissure angle slightly improved at rest (group 2: 0.95° ± 0.53°, group 3: 1.35° ± 1.02°) and while smiling (group 2: 2.06° ± 0.67°, group 3: 1.23° ± 0.56°). In group 1, reduced tongue morbidity was found in patients who underwent ansa cervicalis transfer.Conclusion: Facial reanimation with hypoglossal nerve transfer, in combination with hypoglossal nerve neurotization using the ansa cervicalis for complete facial palsy patients, might enable favorable facial reanimation outcomes and reduce tongue morbidity. Facial reanimation using the ansa cervicalis or sural nerve for incomplete facial palsy patients did not lead to remarkable improvements, but it warrants further investigation.

Modified hypoglossal-facial nerve anastomosis for peripheral-type facial palsy caused by pontine infarction: A case report and literature review

“…The procedure achieved reanimation of the facial nerve with a major side effect of tongue dysfunction due to the entire resection of the hypoglossal nerve [ 25 ]. Thus, researchers put forward a modified technique that an anastomosis was performed between the proximal stump of ansa cervicalis and the distal stump of the hypoglossal nerve after classical HFA to avoid morbidity related to tongue function [ 16 , 26 ]. However, there was an argument about the effectiveness of modified HFA in hemiglossal function preservation.…”

“…Hammerschlag et al [ 27 ] also denied the usefulness of ansa cervicalis-hypoglossal distal stump anastomosis in tongue function protection. However, a recent study by Won Young Koo et al [ 16 ] showed that facial reanimation with hypoglossal nerve transfer, combined with hypoglossal nerve neurotization using the ansa cervicalis for complete facial palsy patients, might enable favorable facial restoration and reduce the incidence of tongue dysfunction. The Department of Neurosurgery at Xinhua Hospital believed that the advancement in surgical skills in recent years may improve the effectiveness of this modified HFA in hemiglossal function preservation.…”

“…The surgical technique detail was the same as previously described [ 16 ]. Briefly, we did a preauricular skin incision routinely at first and then completed exposure and dissection of the hypoglossal nerve.…”

“…Moreover, several studies have reported favorable results in the restoration of the mimetic muscles function after the use of the ansa cervicalis [ 14 , 15 ]. At the Department of Neurosurgery in Xinhua Hospital, this surgical procedure was adopted, in which the distal stump of the hypoglossal nerve was sutured with the proximal stump of the ansa cervicalis after end-to-end hypoglossal-facial nerve anastomosis as previously described [ 16 ]. According to our experience, facial palsy patients with this technique acquired favorable outcomes and the risk of tongue-related morbidities was significantly decreased.…”

Facial palsy reconstruction

“…Furthermore, the high motor neuron content of the masseter nerve allows for superior muscle mobility compared to facial nerve cross-transplantation. In general, splitting the hypoglossal nerve can reduce donor site defects such as dysarthria and masticatory disorders [ 23 ]. Biofeedback training after nerve crossover can aid in the control of voluntary facial muscle movements and reduce synkinesis.…”