Name:
10.3171/2022.10.FOCVID2290
Description:
10.3171/2022.10.FOCVID2290
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Duration:
T00H08M35S
Embed URL:
https://stream.cadmore.media/player/edbf24b8-7337-4ab6-8a0b-fa095b1a245e
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https://cadmoreoriginalmedia.blob.core.windows.net/edbf24b8-7337-4ab6-8a0b-fa095b1a245e/14. 22-90.mp4?sv=2019-02-02&sr=c&sig=5lAY2VYpTaHRXx5g%2BKLUqa4Krqzc1ldoJhmzDKZM5z4%3D&st=2025-09-28T05%3A22%3A49Z&se=2025-09-28T07%3A27%3A49Z&sp=r
Upload Date:
2022-11-21T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER: Hello. In this video, we will show you the technical nuances of a surgical nerve transfer involving partial hypoglossal to facial nerve neurorrhaphy for the treatment of chronic facial nerve palsy. This is a 45-year-old lady who, in June 2021, underwent surgery for total resection of a CPA schwannoma but was observed to have a House-Brackmann grade VI palsy of the facial nerve, as well as complete loss of the eight cranial nerve function.
SPEAKER: Over the first postoperative year, she experienced no facial recovery and was referred to us. This is the patient just prior to undergoing facial nerve repair, still exhibiting a complete House-Brackmann grade VI facial nerve palsy. Spontaneous recovery can occur up to 1 year postsurgical excision of schwannoma if intraoperative physiology integrity is confirmed. When anatomical integrity is lost during removal of a schwannoma, facial reanimation can be considered at 3 months.
SPEAKER: Otherwise, waiting up to 9 to 12 months is acceptable. The surgical procedure involves a retroauricular mastoidectomy followed by facial nerve and partial hypoglossal nerve neurorrhaphy. This approach has been reported in numerous publications and first described roughly 2 decades ago. Previously, complete or half of the hypoglossal was used for the neurorrhaphy, which lead to long-term hypoglossal morbidity.
SPEAKER: Our technique of dissecting epineurum of facial nerve reduces the width of the hypoglossal nerve required to anastomose, preventing tongue morbidity associated to the older techniques. Basically consists of drilling out the mastoid segment of the facial nerve and sectioning the nerve as proximal as possible to permit nerve transfer of part of the 12th cranial nerve to it.
SPEAKER: This is the typical retroauricular approach, where you can see continuation of the incision 1 or 2 cm behind the angle of the mandible at the neck. The procedure involves several steps. The first one involves drilling of the mastoid bone to free the mastoid segment of the facial nerve after creating a retroauricular incision. Usually, this can be performed either by an audiologist or by a neurosurgeon with both training and experience in mastoid bone drilling.
SPEAKER: We begin by opening the antrum and middle ear cavity, recalling that this patient had already lost the auditory function. Consequently, opening the middle ear cavity carries no auditory risk. Once we obtain an adequate length of the facial nerve, which includes opening of the third part or mostly distal segment of the second portion of the facial nerve, we elevate the nerve from the bone.
SPEAKER: To achieve this, we need to completely free the nerve at its mastoid segment, which requires severing the nerve of the chorda tympani. Once the facial nerve is free, it can be cut as proximal as possible and lifted up from the bone. The second step of the procedure is neck dissection to access the hypoglossal nerve.
SPEAKER: To do this, we extend our incision into the neck, dissecting it until the posterior part of the digastric muscle. Below the digastric, we'll find the hypoglossal nerve, which can be identified using nerve stimulation. At this point, the ansa hypoglossi, also called ansa cervicalis, is a loop of nerve that is part of the cervical plexus, can be identified and dissected.
SPEAKER: Stimulation of hyperglossi will cause contraction of the ipsilateral hemitongue, which can be felt by inserting one's finger into the patient's mouth. The procedure's third stage entails dissecting of the intracranial facial nerve, opening the stylomastoid foramen, and redirecting the mastoid segment of the facial nerve downward.
SPEAKER: This is one of the most critical parts of the procedure. While doing this, you will come to see the parotid gland and extracranial facial nerve. Adherence of the facial nerve to the stylomastoid foramen is very strong at this part. Both segments of the facial nerve must be dissected extracranially and then intracranially without hurting the nerve itself. To do this, several branches of the nerve must be cut, including, for instance, the branch to the digastric muscle, which, of course, already is denervated by the facial nerve palsy so no additional morbidity is sustained.
SPEAKER: Once we free the nerve of the stylomastoid foramen, we redirect the nerve downward toward the hypoglossal nerve. The greater auricular nerves can be preserved as seen. The fourth step involves working on the facial nerve, which begins with microsurgical dissection of the epineurum. Typically, within the epineurum, the facial nerve diminished to half its former width, which is crucial to obtaining a narrower facial nerve and thereby needing to harvest less of the hypoglossal nerve.
SPEAKER: The fifth surgical step entails opening the epineurum and dissecting fascicles of the hypoglossal nerve. At this point, the hypoglossal nerve is either mono- or oligofascicular, so there is usually not much connective tissue. Again, employing microsurgical techniques, we separate just the part that we need to completely cover the surface of the facial nerve, which is usually between one-third to at most one- half of the hypoglossal nerve.
SPEAKER: Once this is done, stitches can be placed. Remember that because there is no longer any epineurum, the stitches must be as superficial as possible. Only two or at most three stitches is perfect between the donor and the receptor nerve. And this ensures that all stitches are superficial enough not to injure both donor and receptor nerves. Gelfoam and fibrin glue are used to strengthen the sutures.
SPEAKER: In our experience, one or two sutures along with application of glue gives better results, with 90% of success of this technique as published before. We don't have any personal experience with the use of conduit wraps or glue alone. We don't disapprove these techniques as possible methods of neurorrhaphy. Only using glue without suturing could eventually increase the risk of dehiscence of the nerve.
SPEAKER: Here, the typical surgical outcome of this procedure is shown in another patient who sustained a complete palsy that had persisted 9 months after complete resection of a vestibular schwannoma. Eighteen months after undergoing the above-described surgical procedure, patient has good symmetry of both the mouth and remaining face and good eye closure. She was very satisfied with the surgical outcome. These are some references we used during the creation of this video.
SPEAKER: We want to thank you all for your attention.
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