Microcirculation evaluation of facial nerve palsy using laser speckle contrast imaging: a prospective study.

OBJECTIVE: Facial nerve palsy (FNP) is a common disease in the otorhinolaryngological department. Besides the main symptom of motionlessness occurring in the ipsilateral facial muscles in FNP, there are other common complaints of numbness, stiffness and tightness in ipsilateral face described by the patients. Based on our pilot study, we further investigated the relevance between these complaints and facial microcirculation. METHOD: Function of facial microcirculation was evaluated by laser speckle contrast imaging (LCSI). Facial perfusion was measured in 143 patients with facial nerve palsy (FNP) at the first visit and follow-up visit under the same conditions. RESULTS: Difference in FNP patients' facial microvascular perfusions between ipsilateral and contralateral side was significant (P = 0.0002613). Facial perfusion of patients with Bell's palsy (P = 00089) and facial nerve tumors (P = 0.025110) was significantly decreasing in the ipsilateral side. Improvement of perfusion could be seen after treatment. CONCLUSION: A positive correlation of FNP severity and microvascular impairment can be noticed. During treatment, patients' ipsilateral perfusion could increase. Therefore, this objective method can measure ipsilateral perfusion in the patients with FNP and the ipsilateral microvascular impairment can be detected through this method.

Treatment of Head and Neck Arteriovenous Malformations Involving the Facial Nerve: A Tailored Algorithm.

BACKGROUND: Head and neck arteriovenous malformations (AVMs) involving branches of the facial nerve often cause tremendous cosmetic, functional, and psychological problems that are challenging to treat. We proposed an algorithm to obtain the optimal treatment and esthetic outcome. METHODS: Medical records of 24 patients were reviewed between 2002 and 2015. The lesions were classified into 4 types: type 1, involving no more than 2 facial nerve branches, with a maximal diameter of lesion of 5 cm or less (n = 7); type 2, involving no less than 2 facial nerve branches, with a maximal diameter of lesion of greater than 5 cm (type 2a, facial nerve preservation, n = 8; type 2b, facial reanimation, n = 5); and type 3, involving the mastoid segments or the trunk of the facial nerve (n = 4). Treatment efficacy was assessed and facial function was evaluated using the regional House-Brackmann Facial Nerve Grading System. RESULTS: Cure was achieved in 11 (45.8%) patients, and improvement was achieved in 12 (50.0%) patients, with a follow-up of 36.3 ± 32.9 months (range, 12-144 months). There was no significant difference of the regional House-Brackmann Facial Nerve Grading System score before and after treatment (type 1, unchanged; type 2a, P = 0.356; type 2b, P = 0.423; type 3, unchanged). Treatment outcomes were not significantly related to the type of nerve involvement (P = 1.000) and the facial reanimation procedure (P = 1.000). CONCLUSIONS: Surgical excision or ethanol embolization alone is efficient for type 1 AVMs. The optimal approach for type 2a AVMs was surgery, followed by well-vascularized tissue transfer. In type 2b AVMs, the satisfied treatment results are achieved by lesion excision and immediate facial reanimation. A 2-stage strategy may result in contented treatment outcome in type 3 AVMs.

Mitochondrial Cyclophilin D as a Potential Therapeutic Target for Ischemia-Induced Facial Palsy in Rats.

Many studies have demonstrated that ischemia could induce facial nerve (FN) injury. However, there is a lack of a suitable animal model for FN injury study and thus little knowledge is available about the precise mechanism for FN injury. The aims of this study were to establish a reliable FN injury model induced by blocking the petrosal artery and to investigate whether dysfunctional interaction between cyclophilin D (CypD) and mitochondrial permeability transition pore (MPTP) can mediate cell dysfunction in ischemic FN injury. The outcomes of ischemia-induced FN injury rat model were evaluated by behavioral assessment, histological observation, electrophysiology, and electron microscopy. Then the levels of CypD and protein that forms the MPTP were evaluated under the conditions with or without the treatment of Cyclosporin A (CsA), which has been found to disrupt MPTP through the binding of CypD. The blocking of petrosal artery caused significant facial palsy signs in the ischemia group but not in the sham group. Furthermore, ischemia can induce the dysfunction of facial nucleus neurons and destruction of the myelin sheath and increase the protein levels of CypD and MPTP protein compared with sham group. Interestingly, treatment with CsA significantly improved neurological function and reversed the ischemia-induced increase of CypD and MPTP proteins in ischemia group. These results demonstrated that blocking of petrosal artery in rats can induce FN injury and the mechanism may be related to the disruption of MPTP by CypD.

Management of vessels passing through the facial nerve in the treatment of hemifacial spasm.

BACKGROUND: In hemifacial spasm, it is extremely rare to find a vessel passing through the facial nerve. In this study, we present our experience of the surgical treatment of four such patients. METHODS: From January 2010 to Match 2015, we treated 2,576 hemifacial spasm patients with microvascular decompression in our department. Of these, four had an intraneural vessel. Intraoperative findings and treatment were recorded, and postoperative outcomes were analyzed. RESULTS: In three patients, the intraneural vessel was the anterior inferior cerebellar artery, which we wrapped with small pieces of wet gelatin and Teflon sponge. A small vein found in the fourth patient was treated with facial nerve combing. Complete decompression was achieved and abnormal muscle response disappeared. Three patients got an excellent result and one patient got a good result. One patient had postoperative facial paralysis, which improved over 10 months of follow-up. CONCLUSION: If an artery passes through the facial nerve, it can be decompressed by wrapping the vessel with wet gelatin and Teflon sponge. If a vein passes through the facial nerve, combing can be used. Intraoperative abnormal muscle response monitoring is very helpful in achieving complete decompression.

Anatomical study of medial zygomaticotemporal vein and its clinical implication regarding the injectable treatments.

BACKGROUND: The medial zygomaticotemporal vein (MZTV), clinically known as sentinel vein, has been observed in the vicinity of the temporal branch of the facial nerve during endoscopic procedures aiming to lift the upper face. The aim of the present study was to describe the topography of the MZTV with reference to the superficial landmarks for providing detailed anatomical information during injectable treatment procedures. METHODS: Eighteen hemifaces were harvested from nine embalmed Korean adult cadavers (5 males and 4 females, mean age 76 years). The piercing location, vascular diameter, drainage pattern of the MZTV, and its relationship with the orbicularis oculi muscle (OOc) were recorded photographically, and using diagrams and written notes. RESULTS: The piercing point of the MZTV was located 26.8 ± 5.9 mm from the lateral epicanthus, 18.8 ± 6.9 mm lateral to the plane (HP) through the tragus and the lateral epicanthus, and 19.0 ± 5.4 mm superior to the plane (VP) through the lateral epicanthus point and perpendicular to the HP. The diameter of the MZTV at the piercing point was 1.9 ± 0.8 mm. All of the MZTV ultimately connected with the middle temporal vein (MTV). In particular, the MZTV was connected the MTV by anastomosing with the periorbital vein. Anastomosis of the MZTV and a well-developed periorbital vein was found in 27.8 % of cases. CONCLUSION: The physician must determine the location of the MZTV and should be able to accurately estimate its connection with significant veins at the temple to reduce the risk of severe complications during injectable treatments.

The fallopian canal: a comprehensive review and proposal of a new classification.

INTRODUCTION: The facial nerve follows a complex course through the skull base. Understanding its anatomy is crucial during standard skull base approaches and resection of certain skull base tumors closely related to the nerve, especially, tumors at the cerebellopontine angle. METHODS: Herein, we review the fallopian canal and its implications in surgical approaches to the skull base. Furthermore, we suggest a new classification. CONCLUSIONS: Based on the anatomy and literature, we propose that the meatal segment of the facial nerve be included as a component of the fallopian canal. A comprehensive knowledge of the course of the facial nerve is important to those who treat patients with pathology of or near this cranial nerve.

Hemifacial spasm and neurovascular compression.

Hemifacial spasm (HFS) is characterized by involuntary unilateral contractions of the muscles innervated by the ipsilateral facial nerve, usually starting around the eyes before progressing inferiorly to the cheek, mouth, and neck. Its prevalence is 9.8 per 100,000 persons with an average age of onset of 44 years. The accepted pathophysiology of HFS suggests that it is a disease process of the nerve root entry zone of the facial nerve. HFS can be divided into two types: primary and secondary. Primary HFS is triggered by vascular compression whereas secondary HFS comprises all other causes of facial nerve damage. Clinical examination and imaging modalities such as electromyography (EMG) and magnetic resonance imaging (MRI) are useful to differentiate HFS from other facial movement disorders and for intraoperative planning. The standard medical management for HFS is botulinum neurotoxin (BoNT) injections, which provides low-risk but limited symptomatic relief. The only curative treatment for HFS is microvascular decompression (MVD), a surgical intervention that provides lasting symptomatic relief by reducing compression of the facial nerve root. With a low rate of complications such as hearing loss, MVD remains the treatment of choice for HFS patients as intraoperative technique and monitoring continue to improve.

Intermediate nerve neuralgia can be diagnosed and cured by microvascular decompression.

Here, we present a case of a 55-year-old woman with a 10-year history of hemifacial spasm accompanied by 1-month ipsilateral paroxysmal otalgia. Magnetic resonance imaging revealed the presence of vessels around the facial nerve root. Surgical exploration via suboccipital retromastoid craniotomy showed converging compression of the facial nerve root and intermediate nerve from both sides by an anterior inferior cerebellar artery loop. The patient's hemifacial spasm and ipsilateral otalgia were completely relieved after microvascular decompression of the facial nerve root and intermediate nerve. Intraoperative findings and the postoperative result of this case confirmed that vascular compression of the intermediate nerve was the exclusive cause of paroxysmal otalgia. The presence of ipsilateral hemifacial spasm, combined with preoperative neuroimaging studies, contributed to the diagnosis of intermediate nerve neuralgia. Microvascular decompression should be considered for the management of patients with intermediate nerve neuralgia.

Microvascular decompression for hemifacial spasm: focus on late reoperation.

The objective of this study is to investigate late repeat microvascular decompression (MVD) with persistent or recurrent hemifacial spasm (HFS) and to compare the clinical characteristics, intraoperative findings, complications, and outcomes with first MVD. We analyzed MVDs performed at the University of Pittsburgh Medical Center between January 1, 2000 and December 31, 2007. Thirty-three patients who underwent late redo MVDs were classified as group I and 243 patients who underwent their first MVD as group II. Clinical data were collected to analyze the difference between the two groups. The mean follow-up period was 54.48 months (range, 9-102 months). There is no significant difference in preoperative clinical characteristics (gender, age, side of MVD, botox usage, facial weakness) between the two groups. In present study, we found a vein as the offending vessel in significantly more number of patients who underwent repeat MVD as compared to first MVD (P = 0.02). The lateral spread response disappeared in 66% of patients during repeat MVDs, which is not different from those undergoing their first MVD. No difference in the relief rate was found during the immediate postoperative, discharge, or follow-up stages between repeat and first MVD. Moreover, no difference was found in the incidence of complications between repeat MVD and first MVD. Late repeat MVD for HFS is an effective and safe procedure. No specific preoperative clinical characteristics were identified in patients with repeat MVD. Intraoperative monitoring with lateral spread response (LSR) is an effective tool to evaluate adequate decompression. In patients with persistent LSR at the end of the procedure, facial nerve compression from a vein should be examined. We believe that it is important to undergo a repeat MVD for failed HFS relief irrespective of the timing of the operation.

Microvascular decompression of the root emerging zone for hemifacial spasm: evaluation by fusion magnetic resonance imaging and technical considerations.

OBJECT: The root exit zone (RExZ) of the facial nerve has been considered to be the target in microvascular decompression (MVD) for hemifacial spasm. However, more proximal segments with oligodendrocyte-derived myelin, where the facial nerve root emerges at the pontomedullary sulcus and adheres to the brainstem surface (root emerging zone [REmZ]), may also be susceptible to neurovascular compression. This study evaluated the predictive value of magnetic resonance (MR) imaging in detecting and assessing the features of vascular compression, especially in the pontomedullary sulcus, and describes the technical considerations of MVD procedures for the more proximal segments of the facial nerve. METHODS: Twenty patients treated with MVD underwent three-dimensional constructive interference in steady-state MR imaging and three-dimensional time-of-flight MR angiography. Their fusion images were used to evaluate the anatomical neurovascular relationships and intraoperative findings were analyzed. RESULTS: Most offending arteries at the REmZ and the RExZ of the facial nerve were correctly identified by fusion MR imaging. During surgery, neurovascular contacts were identified at one or more segments of the facial nerve in all patients. The REmZ of the facial nerve was affected in 55 % of the patients. The most common offending vessel at the REmZ was the posterior inferior cerebellar artery rather than the anterior inferior cerebellar artery. The key procedure to explore the deep-seated REmZ in the pontomedullary sulcus was full dissection of the lower cranial nerves to the brainstem origin. CONCLUSIONS: Our definition more correctly describes the specific anatomical relationship of the facial nerve origin from the brainstem and the clinically relevant target for MVD surgery. Fusion MR imaging is very useful to identify neurovascular contacts at both the RExZ and the REmZ of the facial nerve.

[Guiding values of facial nerve 3D-TOF-MRA and 3D-FIESTA scan for primary hemifacial spasm operation].

OBJECTIVE: To explore the operative guiding values of facial nerve three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and three-dimensional fast imaging employing steady state acquisition three-dimensional fast imaging employing steady state acquisition (3D-FIESTA) scan. METHODS: A total of 125 cases of primary hemifacial spasm was treated at our hospital from 2004 to 2012. Among them, 80 cases received preoperative facial nerve MRA scan. The imaging and intraoperative findings were compared to determine the responsible blood vessels. RESULTS: Responsible blood vessels were found in all 80 cases. Sixty patients (75%) had the involvement of single vessel of anterior inferior cerebellar artery (AICA, n = 57), posterior inferior cerebellar artery (PICA, n = 1), superior cerebellar artery (SCA, n = 1) and vertebral artery (VA, n = 1). Two or more vessels were implicated in 9 patients (11.25%). The culprits were AICA+ internal auditory artery (n = 8) and PICA+ internal auditory artery (n = 1). The source of responsible vessels of 11 cases could not be determined before surgery. Through intraoperative anatomy, 59 patients had single vessel lesions, including AICA (n = 53), PICA (n = 4), SCA (n = 1) and VA (n = 1). Among 14 cases of multiple vessels, there were AICA + internal auditory artery (n = 7), internal auditory artery + PICA (n = 2), AICA + brain stem perforating artery (n = 3) and AICA + vein (n = 2). Seven cases were uncertain. No significant statistical difference existed between two groups. CONCLUSION: Facial nerve 3D-TOF-MRA and 3D-FIESTA scan can identify the status of responsible blood vessels to guide operations.

The petrosal artery and its variations: a comprehensive review and anatomical study with application to skull base surgery and neurointerventional procedures.

BACKGROUND: The petrosal artery supplies several structures at the skull base and is often the focus of various neurointerventional procedures. Therefore, knowledge of its anatomy and variations is important to surgeons and interventionalists. MATERIALS AND METHODS: Twenty latex injected cadaveric heads (40 sides) underwent microsurgical dissection of the petrosal artery. Documentation of the course of the artery and its branches were made. Measurements of the petrosal artery's length and diameter were performed using microcallipers. RESULTS: A petrosal artery was identified on all sides. The mean length and diameter of the artery within the middle cranial fossa was 2.4 cm and 0.38 mm, respectively. Branches included the following: dural, ganglionic, V3 branches, branches extending through the foramen ovale, branches directly to the greater petrosal and lesser petrosal nerves, branches to the floor of the hiatus of the greater and lesser petrosal nerves, branch to the arcuate eminence, and superior tympanic artery. No statistically significant differences were noted between male and female specimens, but right-sided petrosal arteries were in general, larger in diameter than left sides. CONCLUSIONS: A thorough anatomical knowledge of the petrosal artery and to its relationship to the facial nerve and other neurovascular structures is necessary to facilitate effective endovascular treatment and to preclude facial nerve complications.

Normal and pathological findings for the facial nerve on magnetic resonance imaging.

AIM: To demonstrate the enhanced radiological anatomy and common pathological conditions of the facial nerve by using magnetic resonance imaging (MRI). MATERIALS AND METHODS: A retrospective review of the MRI findings of the facial nerve of 146 patients who visited a tertiary academic referral center was conducted. RESULTS: The radiological anatomy of the facial nerve was well illustrated using MRI, as were most of the common pathological conditions of the facial nerve. CONCLUSIONS: Enhancement of the facial nerve in MRI should be correlated with the clinical data. Normal individuals can show enhancement of the tympanic or vertical segments of the facial nerve. Enhancement of the labyrinthine portion of the nerve is almost diagnostic of Bell's palsy. No specific enhancement patterns were observed for tumours or for infections of the middle or external ear. A larger population study is required for the accurate assessment of facial nerve enhancement in multiple sclerosis patients.

Intraoperative continuous monitoring of evoked facial nerve electromyograms in acoustic neuroma surgery.

BACKGROUND: Preservation of facial nerve function is one of the most important goals in acoustic neuroma surgery. We have been using intraoperative continuous monitoring of evoked facial nerve electromyograms (EMGs) since 1997 in acoustic neuroma surgery. We therefore investigated surgically treated patients to clarify the usefulness of this monitoring, and to determine safety criteria for preserving facial nerve function. METHODS: This intraoperative continuous monitoring of evoked facial nerve EMG is a method for checking the EMG evoked by continuous direct electrical stimulation of the facial nerve during tumor excision. The greatest advantage of this method is the ability to identify changes in EMG in real time. We retrospectively investigated 216 patients with surgically treated acoustic neuroma to identify correlations between parameters in this monitoring and postoperative facial nerve function immediately and 1 year after surgery. RESULTS: In these patients, the functional preservation rate of the facial nerve (House and Brackmann grade 1 or 2 at 1 year after surgery) was 98.6% with a 98.2% mean tumor resection rate. Amplitude preservation ratio correlated significantly with facial nerve function both immediately and 1 year after surgery. To avoid severe facial nerve palsy, a warning criterion of amplitude preservation ratio >50% appears useful. CONCLUSIONS: Postoperative course of facial nerve function appears predictable using intraoperative continuous monitoring of evoked facial nerve EMGs. This monitoring is useful to increase the tumor excision rate while avoiding severe postoperative facial nerve palsy in acoustic neuroma surgery.

Morphological study of the vasa nervorum in the peripheral branch of human facial nerve.

Given the length of axons reaching to distal regions, all peripheral nerves must derive nutrient supply not only for the nerve cell body, but also for the peripheral parts. Along the course of a peripheral nerve, in general, nutrient vessels accompany nerve fibers to peripheral regions in the form of "vasa nervorum" derived from the epineurium, reaching the endoneurium through the perineurium and forming a capillary plexus. In addition, in reconstructive procedures in plastic surgery, anastomosis of not only nerves, but also the vasa nervorum, has been reported to achieve improved outcomes. The present study therefore observed morphological features of the blood supply to the distal portion of the facial nerve in 14 sides of 14 adult cadavers (age at death, 46-86 years) under stereo microscopy after dye injection. The region of the epineurium was also observed under scanning electron microscopy (SEM). The vasa nervorum was seen to derive from a complex reticulation structure formed mainly by the superficial temporal, facial, transverse facial and zygomatico-orbital arteries with collateral supply from the supraorbital, deep temporal, buccal arteries and parotid branches. SEM showed that one capillary accompanied each perineurium in each nerve fascicle.

Dry Mouth Caused by Facial Nerve Ischemia due to Subarachnoid Hemorrhage: An Experimental Study.

OBJECTIVE: Parasympathetic network damage results in facial nerve damage, sublingual ganglion degeneration, sublingual gland dysfunction, and dry mouth. In this study, subarachnoid hemorrhage (SAH) was considered to be the cause of dry mouth. METHODS: We assessed 23 hybrid rabbits, including 5 control (group 1, Control). One milliliter of serum saline was injected into the cisterna magna of 5 animals (group 2). SAH was induced by injecting 1 mL of autologous blood into the cisterna magna of 13 animals (group 3). The animals were killed after 3 weeks of induction. The animals' sublingual ganglion and sublingual gland were excised for histopathological examination. The number of degenerated cells in the sublingual ganglion, secretory vesicles, and secretory granules in the sublingual gland that contain salivary components were estimated using Sequential Window Acquisition of All Theoretical Mass Spectra data analysis. The values were compared by the Mann-Whitney U-test. RESULTS: The numbers of secretory vesicles in the sublingual gland were 5.3 ± 1.1 × 103 (group 1), 4.23 ± 0.45 × 103 (group 2), and 1.56 ± 0.22 × 103 (group 3); the numbers of secretory vesicles containing saliva in the sublingual gland were 324 ± 12.18 (group 1), 263 ± 36.23 (group 2), and 114 ± 23.14 (group 3); and the numbers of degenerated cells in the sublingual ganglion were 11 ± 3/mm3 (group 1), 98.43 ± 15.54/mm3 (group 2), and 346 ± 12.28/mm3 (group 3) (P < 0.05). CONCLUSIONS: Clinical findings in infection and diseases such as Sjögren syndrome, aseptic meningitis, and SAH are similar. However, until now, SAH has not been demonstrated experimentally to cause dry mouth. Discovering that SAH might cause dry mouth might prevent unnecessary use of antibiotics and decrease morbidity due to the wrong or late diagnosis.

Repair of whole rabbit facial nerve defects using facial nerve allografts.

PURPOSE: To investigate the feasibility of repairing whole facial nerve defects with chemically extracted acellular whole facial allografts nerves and its effect on motor conductivity recovery. MATERIALS AND METHODS: Whole nerve defects (branches and trunk) were made in 4 rabbit groups (n = 18), and the nerve defect was bridged using 1) acellular facial nerve allografts, 2) facial nerve isografts, 3) acellular peroneal nerve allografts, and 4) peroneal nerve isografts. Six months later, cell morphology, nerve microbeam distribution, angiogenesis, and collagen were observed in the distal and center of the grafts with special trichrome staining. The regenerated nerve fibers and Schwann cells in the anastomosis site were immunohistochemically stained. Nerve axon numbers and passing rates were analyzed with computer-captured images. The regenerated nerve ultrastructure was analyzed by transmission electron microscopy. RESULTS: Regenerated nerve fibers and vessels were found in the grafts, with no differences between groups A and B. Groups C and D had poor nerve continuity with little vascular regeneration. The distal segments of nerve transplants in groups A and B showed strong positive neurofilament staining, higher than in groups C and D. In groups A and B, many long spindle-shaped Schwann cells proliferated longitudinally in the nerve transplant, but less in groups C and D. Myelinated nerve fibers were found in the distal facial nerve. There were no differences between groups A and B in fiber number and myelin sheath thickness, which were much lower than normal, whereas little myelin sheath regeneration was observed in groups C and D. CONCLUSION: Chemically extracted acellular whole facial nerve allografts are feasible for repairing whole facial nerve defects.

Surgical Anatomy of the Labyrinthine and Subarcuate Arteries and Clinical Implications.

OBJECTIVE: To study the surgical anatomy of the labyrinthine artery (LA) and the subarcuate artery (SA), their anatomic relationships, and clinical implications, as injury of the LA can result in hearing loss. METHODS: Ten formalin-fixed, latex-colored specimens were studied (20 sides). After retrosigmoid craniotomy and neurovascular dissection under microscopic magnification, 4-mm 0° and 30° endoscopic lenses were used to improve visualization. Results were statistically analyzed. RESULTS: The LA was a constant artery that followed the vestibulocochlear nerve into the internal auditory canal. The SA was an inconstant artery that ended in the dura mater around the subarcuate fossa in 35% of cases. The LA originated from the anterior inferior cerebellar artery in 89.3% of specimens and from the basilar artery in 10.7% of specimens. The SA branched off from the anterior inferior cerebellar artery when present. The origin of the LA was inferomedial to the vestibulocochlear nerve in most cases (71.4%), whereas the SA was usually lateral (70%). The distal portion of the LA was inferomedial to the vestibulocochlear nerve in 71.4% of cases. The distal portion of the SA was superolateral to the nerve in all cases (P < 0.00001). CONCLUSIONS: Knowledge of the different trajectory and anatomic relationship of the LA and the SA with the vestibulocochlear nerve is of paramount importance to differentiate them during surgery. The LA is usually inferomedial to the vestibulocochlear nerve at its distal and proximal aspects, whereas the SA usually originates lateral and ends superolateral to the nerve.

Facial Nerve Arterial Arcade Supply in Dural Arteriovenous Fistulas: Anatomy and Treatment Strategies.

BACKGROUND AND PURPOSE: Endovascular treatment of petrous dural AVFs may carry a risk of iatrogenic facial nerve palsy if the facial nerve arterial arcade, an anastomotic arterial arch that supplies the geniculate ganglion, is not respected or recognized. Our purpose was to demonstrate that the use of a treatment strategy algorithm incorporating detailed angiographic anatomic assessment allows identification of the facial nerve arterial arcade and therefore safe endovascular treatment. MATERIALS AND METHODS: This was a retrospective cohort study of consecutive petrous dural AVF cases managed at Toronto Western Hospital between 2006 and 2018. Our standard of care consists of detailed angiographic assessment followed by multidisciplinary discussion on management. Arterial supply, primary and secondary treatments undertaken, angiographic outcomes, and clinical outcomes were assessed by 2 independent fellowship-trained interventional neuroradiologists. RESULTS: Fifteen patients had 15 fistulas localized over the petrous temporal bone. Fistulas in all 15 patients had direct cortical venous drainage and received at least partial supply from the facial nerve arterial arcade. Following multidisciplinary evaluation, treatment was performed by endovascular embolization in 8 patients (53%) and microsurgical disconnection in 7 patients (47%). All patients had long-term angiographic cure, and none developed iatrogenic facial nerve palsy. CONCLUSIONS: By means of our treatment strategy based on detailed angiographic assessment and multidisciplinary discussion, approximately half of our patients with petrous AVFs were cured by endovascular treatment, half were cured by an operation, and all had preserved facial nerve function.

Facial Nerve Branching Patterns Vary With Vascular Anomalies.

OBJECTIVES: At our institution, in vivo facial nerve mapping (FNM) is used during vascular anomaly (VAN) surgeries involving the facial nerve (FN) to create an FN map and prevent injury. During mapping, FN anatomy seemed to vary with VAN type. This study aimed to characterize FN branching patterns compared to published FN anatomy and VAN type. STUDY DESIGN: Retrospective study of surgically relevant facial nerve anatomy. METHODS: VAN patients (n = 67) with FN mapping between 2005 and 2018 were identified. Results included VAN type, FN relationship to VAN, FNM image with branch pattern, and surgical approach. A Fisher exact test compared FN relationships and surgical approach between VAN pathology, and FN branching types to published anatomical studies. MATLAB quantified FN branching with Euclidean distances and angles. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) analyzed quantitative FN patterns amongst VAN types. RESULTS: VANs included were hemangioma, venous malformation, lymphatic malformation, and arteriovenous malformation (n = 17, 13, 25, and 3, respectively). VAN FN patterns differed from described FN anatomy (P < .001). PCA and HCA in MATLAB-quantified FN branching demonstrated no patterns associated with VAN pathology (P = .80 and P = .91, one-way analysis of variance for principle component 1 (PC1) and priniciple component 2 (PC2), respectively). FN branches were usually adherent to hemangioma or venous malformation as compared to coursing through lymphatic malformation (both P = .01, Fisher exact). CONCLUSIONS: FN branching patterns identified through electrical stimulation differ from cadaveric dissection determined FN anatomy. This reflects the high sensitivity of neurophysiologic testing in detecting small distal FN branches. Elongated FN branches traveling through lymphatic malformation may be related to abnormal nerve patterning in these malformations. LEVEL OF EVIDENCE: NA Laryngoscope, 130:2708-2713, 2020.