The facial nerve plays a crucial role in facial expression and sensory functions, with irreversible injuries often demanding rehabilitation therapies, with hypoglossal-facial nerve anastomosis (HFA) being one of the treatment options. This systematic review assessed different HFA techniques for facial paralysis, particularly post vestibular schwannoma resection, focusing on effectiveness and associated morbidities. Fifteen studies, comprising a case series and a retrospective cohort, were analyzed. Techniques included end-to-end, split, side-to-side, end-to-side, and jump interpositional graft hypoglossal-facial anastomosis (JIGHFA). Positive outcomes were observed with end-to-end and side-to-side techniques, while the split technique and JIGHFA showed promise. Comparative analyses favored the \'end-to-side\' approach. Shorter intervals between surgery and HFA correlated with improved outcomes. Methodological variations highlight the need for prospective studies with standardized methodologies for robust evidence and informed decision-making on optimal HFA techniques.

UNASSIGNED: A surgical simulation of an endoscope-dominated side-to-end hypoglossal-facial anastomosis was performed to evaluate the feasibility.
UNASSIGNED: Eight anatomical cadaver heads (16 sides) were recruited. The steps in conventional procedures were abbreviated or omitted. A facial nerve was first harvested near its external genu and was used for a side-to-end hypoglossal-facial anastomosis. The stump of the used facial nerve was truncated and recycled immediately caudal to the facial recess in another anastomosis and then recycled again at the stylomastoid foramen. As a recycled stump becomes too short to ensure a side-to-end anastomosis, the hypoglossal nerve was transected in situ, and an endoscopic end-to-end hypoglossal-facial anastomosis was attempted. Surgical simulation and quantitative measurement methods were used to analyze the anastomosis effects of different harvested sites of the facial nerve.
UNASSIGNED: Several steps in the conventional procedures provide little benefit in endoscopic surgery. A facial nerve stump recycled at the stylomastoid foramen is too short to ensure a tensionless side-to-end anastomosis. An endoscopic end-to-end hypoglossal-facial anastomosis was feasible, although it required more time than the classical microsurgical anastomosis. The greater agility of an endoscope enables the conventional surgical steps to be overlapped or interweaved into the procedure.
UNASSIGNED: The multiple surgical fields and ability to manipulate the viewpoint provided by an endoscope have brought about breakthroughs in classical surgical paradigms. In addition, it is best to choose the sites of the facial nerve harvested near the external genu. If unavailable, an alternative section site could be selected immediately caudal to the facial recess, but cannot be distal to the stylomastoid foramen. The length of the stump should be individualized and preferably optimized with a nerve stimulator.

OBJECTIVE: Localization of the facial nerve trunk (FNT) [i.e., the portion of the facial nerve between the stylomastoid foramen (SMF) and pes anserinus] may be required during various surgical interventions such as parotidectomy and hypoglossal-facial anastomosis. Several landmarks have been proposed for efficient identification of the FNT. We sought to assess the anatomical features of the digastric branch of the facial nerve (DBFN) and its potential as a landmark to identify FNT.
METHODS: Fifteen sides of eight cadaveric heads were dissected to find the DBFN. Anatomic features of DBFN including its point of origin relative to SMF, length, and important relationships, as well as the distance between the insertion point on the digastric muscle and mastoid tip were recorded.
RESULTS: DBFN was found in all specimens originating from the FNT outside the SMF with an average length (± standard deviation) of 15.4 ± 3.4 mm. In all specimens, the DBFN inserted on the superomedial aspect of the posterior belly of the digastric muscle (PBD). In 8/15 specimens, DBFN was accompanied by the stylomastoid artery on its anteromedial side. Average distance (± standard deviation) between the mastoid tip and the nerve insertion point on PBD was 13.6 ± 2.0 mm (range 10-17).
CONCLUSIONS: The DBFN is a reliable landmark for identifying the FNT. It could be consistently identified within 15-20 mm of the mastoid tip on the superomedial aspect of the PBD. The DBFN may be used as a supplementary landmark for efficient localization of the FNT.
METHODS: Not applicable (anatomic study).

BACKGROUND: The greater auricular nerve (GAN) may be used as a nerve graft during neurosurgical procedures to repair damaged nerves. There is extensive literature on localization of the GAN at the posterior triangle of the neck, but objective information on localization of the GAN at the anterior triangle of the neck close to cranial neurosurgical fields is lacking. The aim of this study was to introduce simple and reliable landmarks to localize the GAN at the anterior triangle of the neck to facilitate its harvest during neurosurgical procedures.
METHODS: The GAN was exposed bilaterally in 11 cadaveric specimens at the point of crossing the anterior border of the sternocleidomastoid muscle (anterior greater auricular point [AGA]). Distances from the AGA point to the angle of the mandible and the tip of the mastoid process were measured. Additionally, the location of the crossing point between the GAN and an imaginary line passing through the mastoid tip and the angle of the mandible (M-A line) was found relative to these bony landmarks.
RESULTS: Mean (±SD) distances from the AGA point to the mastoid tip and the angle of the mandible were 29.1 ± 3.4 mm and 27.5 ± 4.5 mm, respectively. The GAN was always found to cross the M-A line in its middle third (mean 48.2% ± 6.9% from the mastoid tip).
CONCLUSIONS: The AGA point and the M-A line are reliable landmarks for locating the GAN at the anterior triangle of the neck and for helping neurosurgeons expose and harvest the GAN efficiently.

BACKGROUND: The hypoglossal (with or without grafts) and masseter nerves are frequently used as axon donors for facial reinnervation when no proximal stump of the facial nerve is available. We report our experience treating facial nerve palsies via hemihypoglossal-to-facial nerve transfers either with (HFG) or without grafts (HFD), comparing these outcomes against those of masseteric-to-facial nerve transfers (MF).
METHODS: A total of 77 patients were analyzed retrospectively, including 51 HFD, 11 HFG, and 15 MF nerve transfer patients. Both the House-Brackmann (HB) scale and our own, newly-designed scale to rate facial reanimation post nerve transfer (quantifying symmetry at rest and when smiling, eye occlusion, and eye and mouth synkinesis when speaking) were used to enumerate the extent of recovery.
RESULTS: With both the HB and our own facial reanimation scale, the HFD and MF procedures yielded better outcome scores than HFG, though only the HGD was statistically superior. HGD produced slightly better scores than MF for everything but eye synkinesis, but these differences were generally not statistically significant. Delaying surgery beyond 2 years since injury was associated with appreciably worse outcomes when measured with our own but not the HB scale. The only predictors of outcome were the surgical technique employed and the duration of time between the initial injury and surgery.
CONCLUSIONS: HFD appears to produce the most satisfactory facial reanimation results, with MF providing lesser but still satisfactory outcomes. Using interposed grafts while performing hemihypoglossal-to-facial nerve transfers should likely be avoided, whenever possible.

BACKGROUND: The hypoglossal facial anastomosis (HFA) is the gold standard for facial reanimation in patients with severe facial nerve palsy. The major drawbacks of the classic HFA technique are lingual morbidities due to hypoglossal nerve transection. The side-to-end HFA is a modification of the classic technique with fewer tongue-related morbidities.
OBJECTIVE: In this study we compared the outcome of the classic end-to-end and the direct side-to-end HFA surgeries performed at our center in regards to the facial reanimation success rate and tongue-related morbidities.
METHODS: Twenty-six successive cases of HFA were enrolled. In 9 of them end-to-end anastomoses were performed, and 17 had direct side-to-end anastomoses. The House-Brackmann (HB) and Pitty and Tator (PT) scales were used to document surgical outcome. The hemiglossal atrophy, swallowing, and hypoglossal nerve function were assessed at follow-up.
RESULTS: The original pathology was vestibular schwannoma in 15, meningioma in 4, brain stem glioma in 4, and other pathologies in 3. The mean interval between facial palsy and HFA was 18 months (range: 0-60). The median follow-up period was 20 months. The PT grade at follow-up was worse in patients with a longer interval from facial palsy and HFA (P value: 0.041). The lesion type was the only other factor that affected PT grade (the best results in vestibular schwannoma and the worst in the other pathologies group, P value: 0.038). The recovery period for facial tonicity was longer in patients with radiation therapy before HFA (13.5 vs. 8.5 months) and those with a longer than 2-year interval from facial palsy to HFA (13.5 vs. 8.5 months). Although no significant difference between the side-to-end and the end-to-end groups was seen in terms of facial nerve functional recovery, patients from the side-to-end group had a significantly lower rate of lingual morbidities (tongue hemiatrophy: 100% vs. 5.8%, swallowing difficulty: 55% vs. 11.7%, speech disorder 33% vs. 0%).
CONCLUSIONS: With the side-to-end HFA technique the functional restoration outcome is at least as good as that following the classic end-to-end HFA, but the complications related to the complete hypoglossal nerve transection can be avoided. Best results are achieved if this procedure is performed within the first 2 years after facial nerve injury. Patients with facial palsy of longer duration also have the chance for good functional restoration after HFA.

Facial palsy is a relatively common condition, from which most cases recover spontaneously. However, each year, there are 127,000 new cases of irreversible facial paralysis. This condition causes aesthetic, functional and psychologically devastating effects in the patients who suffer it. Various reconstructive techniques have been described, but there is no consensus regarding their indication. While these techniques provide results that are not perfect, many of them give a very good aesthetic and functional result, promoting the psychological, social and labour reintegration of these patients. The aim of this article is to describe the indications for which each technique is used, their results and the ideal time when each one should be applied.