[Postoperative effect analysis of different surgical techniques used in facial nerve reconstruction].

Objective:To investigate the factors and efficacy of different surgical techniques used in facial nerve（FN） reconstruction. Methods:A retrospective analysis was conducted on 24 patients who underwent facial nerve reconstruction surgery in our department from January 2016 to January 2021. The duration of total facial nerve paralysis was less than 18 months. The study included 5 surgical techniques, including 6 cases of FN anastomosis（Group A）, 5 cases of FN grafting（sural nerve or great auricular nerve）（Group B）, 5 cases of side-to-end facial-hypoglossal nerve anastomosis（Group C）, 4 cases of side-to-end FN grafting（sural nerve or great auricular nerve） hypoglossal nerve anastomosis（Group D）, and 4 cases of dual nerve reanimation（Group E）. The postoperative follow-up period was ≥1 year. Results:The HB-Ⅲ level of FN function at 1 year after surgery was 83.3%（5/6） in group A, 60.0%（3/5） in group B, 40.0%（2/5） in group C, 25.0%（1/4） in group D, and 50.0%（2/4） in group E. In patients without multiple FN repair, the incidence of synkinesis was 15.0%（3/20）, while no cases of synkinesis were observed in patients with dual nerve reanimation. The patients who underwent hypoglossal-facial side-to-end anastomosis showed no hypoglossal nerve dysfunction. Conclusion:Different FN repair techniques result in varying postoperative FN function recovery, as personalized repair should be managed. Among the various techniques, FN end-to-end anastomosis after FN transposition is recommended as to reduce the number of anastomotic stoma, while hypoglossal-facial side-to-end anastomosis is advocated as to prevent postoperative hypoglossal nerve dysfunction. Additionally, dual nerve repair can effectively improve smile symmetry and reduce synkinesis, which enhances patients' quality.

Facial Reanimation After Intratemporal Facial Nerve Schwannoma Resection: A Systematic Review.

Objective: To systematically analyze the outcomes of reanimation techniques that have been described for patients undergoing non-fascicle sparing resection of intratemporal facial schwannomas. Methods: A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines of the PubMed, MEDLINE, and Cochrane Central Register of Controlled Trials databases. Results: Eight hundred forty studies were screened with 22 meeting inclusion criteria comprising 266 patients. Most facial nerve reanimations (81.2%) were performed using an interposition nerve graft. The remaining patients underwent hypoglossal-facial nerve transposition (13.9%), primary anastomosis (3.4%), and free muscle transfer (0.1%). Of the reported interposition grafts, the two most utilized were the great auricular (113/199) and sural (86/199) nerves. Interposition nerve grafts resulted in significantly better outcomes in facial nerve function postoperatively than hypoglossal-facial transposition (3.48 vs. 3.92; p < 0.01). There was no difference between interposition grafts. Conclusion: This study systematically reports that interposition nerve grafts, after resection of intratemporal facial schwannoma, result in superior outcomes than hypoglossal-facial nerve transposition in these patients.

An unexpected complication of hypoglossal schwannoma surgery: Cerebrospinal fluid leakage-A case report and literature review.

BACKGROUND: Extracranial hypoglossal schwannoma is a rare tumor primarily treated with surgical excision. This article aims to highlight the potential for unexpected complications intraoperatively, such as cerebrospinal fluid leakage from skullbase to neck. METHODS: A previously healthy 23-year-old male presented with tongue numbness. Magnetic resonance imaging revealed a 17 × 20 mm nodular lesion adjacent to the cervical segment of the internal carotid artery. Surgical excision was scheduled due to suspicion of a neurogenic tumor. RESULTS: Intraoperatively, despite careful handling, cerebrospinal fluid leakage was observed. Manipulation of the mass caused detachment of proximal nerve fibers, potentially indicating avulsion of the hypoglossal nerve from the brainstem or nearby. Clear fluid leakage from the skull base was also noted. CONCLUSION: Thorough preoperative evaluation and patient education regarding potential complications are crucial. This article presents an unexpected complication encountered during surgical excision of extracranial hypoglossal schwannoma, emphasizing the need for awareness and preparedness in such cases.

Increased Body Mass Index Correlates with Less Favorable Postoperative Outcomes After Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea: A Retrospective Cohort Study.

OBJECTIVE: Obstructive sleep apnea is associated with high morbidity. Hypoglossal nerve stimulation (HNS) has become a novel (neuro-) surgical treatment strategy for obstructive sleep apnea, demonstrating good success rates. Beyond predefined inclusion and exclusion criteria, no precise data are available, enabling individual preoperative risk assessment. To improve preoperative risk stratification, this study analyzed individual patient factors that affect outcomes of HNS. METHODS: Fourteen patients treated with unilateral HNS were analyzed retrospectively. Assessed risk factors included: hypertension, diabetes mellitus, depression, smoking, alcohol consumption, body mass index (BMI), and disease duration. Treatment success was defined as a reduction in the postoperative apnea-hypopnea index (AHI) to ≤20 events/hour, with a relative reduction of at least 50% compared to baseline. RESULTS: A significant reduction in the postoperative apnea-hypopnea index was observed in all patients (P < 0.0001). BMI correlated significantly with postoperative AHI scores (95% confidence interval, 0.1519-0.8974; P = 0.018). Significant treatment success was observed in 50% of patients. Compared with the "Excellent Responder group," the "Responder group" demonstrated a significantly higher BMI (95% confidence interval, 1.174-6.226; P = 0.0078). Diabetes, hypertension, disease duration, smoking, depression, and alcohol consumption were not significantly associated with AHI reduction. CONCLUSIONS: Our findings suggest that BMI may be an independent risk factor for the response to HNS, with patients who had less benefit from therapy having significantly higher BMI than "Excellent Responders." Therefore, carefully selecting patients is crucial in obtaining optimal outcomes with HNS therapy, especially those with a high BMI.

Successful Reimplantation of Extruded Lead after Hypoglossal Nerve Stimulation Surgery.

Infection and extrusion of hardware are known complications of hypoglossal nerve stimulation surgery. We present a unique case of an extruded hardware lead successfully managed with reimplantation without need for explantation and new device placement. The topic will be discussed in context of the body of literature related to extruded medical device management. Laryngoscope, 133:2821-2822, 2023.

Upper Airway Stimulation in Female Patients: Safety and Efficacy of a Novel Lateral Approach.

OBJECTIVE: To describe a novel lateral approach for hypoglossal nerve stimulator (HNS) implantation in women and provide evidence for its safety and efficacy. STUDY DESIGN: Retrospective case series. SETTING: Single academic medical center. METHODS: We identified patients implanted with HNS by a single surgeon from January 2017 to December 2021. Patient characteristics, postoperative complications, surgical duration, response to therapy, and need for revision surgery were recorded. RESULTS: One hundred four patients were included, including 93 males and 11 females. The lateral approach for HNS implantation involves placing the chest incision for the implantable pulse generator and respiratory sensor lead vertically in the anterior axillary line instead of horizontally in the infraclavicular area. No changes are made to the stimulator lead placement. All female patients were implanted using a lateral approach and all male patients were implanted via the standard anterior approach. Half of the patients were implanted via a 2-incision technique. The median surgical time duration was equivalent in male and female patients (119 [interquartile range (IQR): 105-138] vs 126 [IQR: 115-141], respectively). Revision was required in 2 (18%) females versus 6 (6%) males (p = .17). There were equivalent rates of therapy response as well as postoperative complications. CONCLUSION: A more cosmetic lateral approach is feasible for HNS in female patients and has a similar rate of adverse events and therapy responsiveness. Additional considerations in female patients include the ability to tolerate mammography as well as HNS implantation in the setting of existing breast implants.

Hypoglossal Nerve Stimulator Explantation Technique and Outcomes: A Retrospective Case Series.

INTRODUCTION: Upper airway stimulation via the hypoglossal nerve stimulator (HGNS) implant is a surgical method for treating obstructive sleep apnea. However, patients may need the implant removed for a variety of reasons. The purpose of this case series is to assess surgical experiences with HGNS explantation at our institution. We report on surgical approach, overall operative times, operative and postoperative complications, and discuss relevant patient-specific surgical findings when removing the HGNS. METHODS: We performed a retrospective case series of all patients that underwent HGNS implantation at a single tertiary medical center between January 9, 2021, and January 9, 2022. Subjects included adult patients who presented to the sleep surgery clinic of the senior author for surgical management of previously implanted HGNS. Patient clinical history was reviewed to determine the timing of the patient's implant, reasons for explant, and postoperative recovery course. Operative reports were reviewed to determine overall duration of surgery and any associated difficulties or deviations from the general approach. RESULTS: Between January 9, 2021, and January 9, 2022, 5 patients had an explantation of their HGNS implant. Explantation occurred between 8 and 63 months of their original implant surgery. The average operative time from incisional start time to close was 162 min for all cases with a range of 96-345 min. No significant complications were reported including pneumothorax and nerve palsy. CONCLUSION: This reported case series outlines the general steps for Inspire HGNS explantation as well as details the experiences in a case series of 5 subjects explanted over the year at a single institution. The results from the cases suggest that the explantation of the device can be performed efficiently and safely.

Intraoperative Neuromonitoring of Hypoglossal Nerves Using Transcranial and Direct Electrical Stimulation During Extracranial Internal Carotid Artery Surgery.

BACKGROUND: We explored whether the electromyogram (EMG) and the motor evoked potential (MEP) are useful for monitoring the function of the hypoglossal nerve during surgery targeting the cervical segment of the internal carotid artery. METHODS: The present study included 6 patients with internal carotid arterial stenosis (1 patient underwent bilateral surgeries) and 1 patient with a cervical carotid artery aneurysm. In 5 of the 8 procedures, the EMGs were recorded. We examined whether changes in the MEP and/or EMG were capable of predicting postoperative hypoglossal nerve deficits. RESULTS: None of the 6 patients who underwent a total of 7 carotid endarterectomy (CEA) procedures experienced postoperative hypoglossal nerve morbidity. In 2 of the 7 procedures, the MEP disappeared or decreased significantly during CEA. In all 4 cases in which the hypoglossal nerve was directly stimulated during CEA, stable and reproducible EMGs were obtained throughout the manipulation of the internal carotid artery. Hypoglossal nerve morbidity was observed in the one case that underwent aneurysm removal and end-to-end anastomosis of the internal carotid artery. In this case, while the MEP decreased significantly during the operation, the EMG showed true-positive results and false-negative results, depending on the stimulation site. CONCLUSIONS: The monitoring of hypoglossal nerve function using EMG appears to be accurate if an appropriate stimulation site is selected. Hypoglossal nerve monitoring using MEP can produce false-positive results. Combined monitoring using both MEP and EMG is recommended in cases where exposure of the hypoglossal nerve is expected to be technically difficult.

The Posterior Belly of Digastric Muscle as the Landmark in Facial Nerve Anastomosis Surgery: Anatomical Study and Case Illustration.

OBJECTIVE: To establish a new method for fast exposure of the facial nerve and hypoglossal nerve during facial nerve anastomosis surgery. METHODS: Dissection of 12 formalin-fixed cadaveric specimens was performed to explore the positional relationship between the posterior belly of digastric muscle (PBD) and the facial nerve and hypoglossal nerve. We retrospectively reviewed patients who underwent facial nerve reconstruction surgery between 2015 and 2020 at Xuanwu Hospital, Capital Medical University, and the optimized surgical strategy based on the PBD was proposed. RESULTS: The trunk of the hypoglossal nerve runs across the external carotid artery after giving off the descendens hypoglossi located within the 1-cm scope deep to the junction of the tendon and belly of the PBD. The mean depth difference between the hypoglossal nerve and the junction of the tendon and belly of the PBD was 5.48 ± 2.24 mm (range, 1.88-9.27 mm). The stylomastoid foramen segment of the facial nerve was revealed after the parotid gland was dissected within the angle between the anterior margin of the mastoid tip and the inferior margin of the cartilage of the external acoustic meatus. CONCLUSIONS: The facial nerve and hypoglossal nerve can be rapidly identified using the PBD as an anatomical landmark. The end-to-end facial-descendens hypoglossi anastomosis is a reliable facial nerve reconstruction method for patients whose facial nerve was damaged during operation.

Efficacy of expansion pharyngoplasty and hypoglossal nerve stimulation in treating sleep apnea.

OBJECTIVE: We investigated whether a palatal conversion procedure combined with a second-stage hypoglossal nerve stimulator (HGNS) insertion can be beneficial for those patients who have a complete concentric velopharyngeal collapse and may initially not meet the criteria for use of HGNS. METHODS: A retrospective chart review included all patients who underwent a planned multi-level sleep surgery including expansion sphincter pharyngoplasty (ESP) followed by HGNS. All patients had a complete concentric collapse (CCC) of the velopharynx (VP) on pre-intervention drug-induced sleep endoscopy (DISE) and were initially not a candidate for HGNS. These patients then underwent ESP followed by a DISE to confirm elimination of the CCC of the VP. They then went on to HGNS implantation several months later followed by a sleep study. RESULTS: A total of 20 patients were identified and included in the retrospective chart analysis. All patients who underwent ESP successfully converted their VP from CCC to an anterior-posterior collapse pattern and thus met inclusion criteria for HGNS. After the HGNS was implanted, patients showed a significant reduction of the mean AHI from 53.9 before ESP to 8.2 after ESP and HGNS and a decrease in the Epworth Sleep Score (ESS) from a mean of 13.3 to 5.7. CONCLUSION: ESP can be effective in eliminating the CCC of the VP thus making patients become HGNS candidates. In selected OSA patients, who have multilevel upper airway obstruction with complete concentric VP collapse, the combination of ESP and HGNS insertion should be considered as a planned 2-staged approach.

The Split Hypoglossal Nerve and Cross-Face Nerve Graft for Dual Innervation of the Functional Muscle Transfer in Facial Reanimation.

Facial paralysis is a disabling deformity. The affected individual is seriously affected both esthetically and functionally. Free functional muscle transfer is currently the corner stone in the management of long-standing facial nerve paralysis. Several nerve options are available to supply the free muscle transfer. These nerves can be used alone or in combination. The aim of this work is to study the possibility and results of dually innervating the free functioning muscle transfer. The dual innervation is done using the split hypoglossal nerve and cross-face nerve graft (CFNG) both sutured in an end-to-end manner to the nerve to gracilis. Twenty-nine patients with unilateral long-standing facial nerve paralysis (more than 1 y) were treated using free gracilis muscle transfer dually supplied by the split hypoglossal nerve and CFNG, both sutured in an end-to-end manner. The gained excursion after the free gracilis transfer was 9 to 29 mm (mean: 17.24 mm). A statistically significant increase ( P -value=0.0001) in the distance from where the midline crosses the lower vermilion border to commissure occurred from preoperative (mean: 16.55 mm) to postoperative setting (mean: 33.79 mm). Spontaneity was achieved in 26 patients (89.6%). In conclusion, dual innervation of the free muscle transfer using both the split hypoglossal nerve and CFNG (both sutured in an end-to-end manner to the nerve to gracilis) is a good possible option to treat long-standing cases of facial nerve paralysis. It yields adequate muscle excursion with acceptable spontaneity.

[Neural Reconstruction for Facial Nerve Palsy].

The basic techniques of nerve reconstruction surgery for facial nerve palsy are end-to-end nerve suture and end-to-side nerve suture. The latter has the epineural window method and the partial neurectomy/neurotomy method for the treatment of "side" nerves. Hypoglossal-facial nerve cross-link graft is a method of nerve reconstruction in which the hypoglossal and facial nerves are bridged by autologous nerve transposition with end-to-side nerve suture. It has been shown to be effective in treating the sequelae of established facial nerve palsy, but there are some issues that prevent the achievement of stable results.

Diagnosis and management of hypoglossal nerve-derived schwannoma in the floor of mouth: a case series.

BACKGROUND: Schwannomas or neurilemmomas are well-encapsulated, benign, solitary, and slow-growing tumors that originate from Schwann cells of the nerve sheath. Extracranial schwannoma is reported to have a relatively high incidence in the tongue while an extremely low incidence in the floor of mouth. In the current study, we presented the first case series of hypoglossal nerve-derived schwannoma in the floor of mouth in Asia. METHODS: A retrospective study of 9 surgical cases of hypoglossal nerve-derived schwannoma in the floor of mouth was performed. The patient and tumor characteristics were evaluated by physical, radiological and pathological examination. Details of operation and complications were also recorded. RESULTS: Hypoglossal nerve-derived schwannoma in the floor of mouth showed a well-defined boundary with a firm texture, smooth surface and good mobility on palpation. The median maximum diameter of the tumors was 4.3 cm (range 2.8-7.0 cm). The median operative time and bleeding volumes were 89.4 min (range 47-180 min) and 99.2 mL (range 15-200 mL), respectively. All cases received complete surgical excision. CONCLUSION: In this study, we presented the diagnosis and management of hypoglossal nerve-derived schwannoma in the floor of mouth for the first time in Asia. The study provided us with a recommendation for consideration of the diagnosis of hypoglossal schwannoma when a patient presents with a mass in the floor of mouth.

Perioperative and Perianesthesia Considerations for Hypoglossal Nerve Stimulator Implantation in Obstructive Sleep Apnea Patients.

Hypoglossal nerve stimulation (Inspire Medical Systems, Maple Grove, Minnesota) is an innovative treatment option for eligible patients with moderate to severe obstructive sleep apnea (OSA). Since U.S. Food and Drug Administration approval in 2014, over 18,000 patients have been implanted. The device includes an implanted pacemaker-sized pulse generator, one sensing lead, and one stimulation lead. During sleep, inspirations and expirations are detected by the sensing lead. At end expiration, the stimulation lead triggers the hypoglossal nerve to contract and stiffen the tongue thus preventing airway obstruction and improving OSA. Perioperative and perianesthesia nurses have an important role in caring for these patients during all aspects of the surgical insertion process: evaluation for eligibility, device implantation, and future visits to the perioperative area for related and unrelated procedures. This article reviews anatomic and physiologic factors contributing to airway collapse in OSA, function of the hypoglossal nerve stimulation device, the evaluation, implantation, and activation process, and considerations for patient care in the perioperative and perianesthesia periods. Precautions needed for other therapies, including Magnetic Resonance Imaging, diathermy, and radiation are also discussed.

Reappraisal of the types of hypoglossal canal: endocranial approach.

This study aims to classify the endocranial variations inside the Hypoglossal Canal (HC) and evaluate the elements of the HC region in terms of sizes, diameters, and distances to the nearby surgical landmarks. The present study was done on 18 adult human fixed cadaver heads bilaterally. The internal opening of HC was examined for the presence of dural or osseos septations in the canal and was classified into five types (Type 1-5). The dimensions of hypoglossal nerve (CN XII) and the distance of intracranial openings of HC from the jugular foramen and jugular tubercle were measured. The prevalence of endocranial HC types were determined on both sides as follows: type 1 (23.53% left, 6.25% right), type 2 (37.5% right, 5.88% left), type 3 (52.94% left, 25% right), type 4 (18.75% right, 17.65% left), type 5 (12.5% right). Understanding the endocranial HC types is crucial for neurosurgeons in the differential diagnosis of various intracranial pathologies for the posterior cranial fossa approach. Knowing the anatomical relationships between the adjacent structures and symmetrical organization of the HC according to the types is crucial in determining surgical strategies and preserving adjacent structures.

Two-Incision Approach for Hypoglossal Nerve Stimulator Placement: A Single Institution Assessment.

OBJECTIVE(S): Upper airway stimulator (UAS) placement is a treatment for obstructive sleep apnea (OSA) with few complications and low morbidity. UAS placement has traditionally been performed using a three-incision approach, however, it has been implanted using a two-incision approach. This approach could significantly decrease operation time without a difference in postoperative complications, demonstrating its safety and feasibility for UAS placement. The objective was to assess operative time and complication rate in the two-incision approach for UAS placement compared to the three-incision approach. STUDY DESIGN: Retrospectively reviewed. METHODS: Patients who underwent UAS placement using the two- or three-incision approach at a single academic institution from November 2014 to June 2021 were retrospectively reviewed. The two-incision approach did not include the incision at the mid-axillary line. Main outcome measures included operation time and complication rates. RESULTS: Three-hundred forty-eight patients underwent UAS placement. The three-incision approach demonstrated an average operation time of 143.3 minutes whereas the two-incision approach averaged 129.4 minutes (P < .001). There was no significant difference in rate of postoperative complications between the two- and three-incision cohorts including pneumothorax (0% vs. 0.4%, P > .99), patient-reported discomfort (5.6% vs. 6.5%, P > .99), activity restriction (0% vs. 1.4%, P > .50), and incisional pain (0.0% vs. 1.0%, P > .99). No patients experienced incision site bleeding or infection. The two-incision approach was associated with decreased rate of revision surgery (0.0% vs. 5.4%, P = .048). CONCLUSION: The UAS two-incision approach proved to have a significantly shorter operative time without an increase in complications as compared to the three-incision approach. This approach is a safe and feasible option. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:1687-1691, 2022.

Microsurgical Anatomy of the Hypoglossal Nerve in the Lateral Approaches to the Craniovertebral Junction: A Study on Fresh Non-Formalin-Fixed Human Specimens.

The aim of this anatomical study is to describe the anatomy of the hypoglossal nerve (HN) from its origin to the extracranial portion as it appears by performing a combined posterolateral and anterolateral approach to the craniovertebral junction (CVJ). Twelve fresh, non-formalin-fixed adult cadaveric heads (24 sides) were analyzed for the simulation of the combined lateral approach to the CVJ. The HN is divided into three main parts: cisternal, intracanalicular, and extracranial The anatomical relationships between the HN and other nerves, muscles, arteries and veins were carefully recorded, and some measurements were made between the HN and related structures. Thus, various landmarks were determined for the easy identification of the HN. Understanding the detailed anatomy of the HN and its relationships with the surrounding structures is crucial to prevent some complications during CVJ surgery.

Hypoglossal and Masseteric Nerve Transfer for Facial Reanimation: A Systematic Review and Meta-Analysis.

Background: Hypoglossal and masseteric nerve transfer are currently the most popular cranial nerve transfer techniques for patients with facial paralysis. The authors performed a systematic review and meta-analysis to compare functional outcomes and adverse effects of these procedures. Methods: A review of online databases was performed to include studies with four or more patients undergoing hypoglossal or masseter nerve transfer without muscle transfer or other cranial nerve transposition. Facial nerve outcomes, time to reinnervation, and adverse events were pooled and studied. Results: A total of 71 studies were included: 15 studies included 220 masseteric-facial transfers, and 60 studies included 1312 hypoglossal-facial transfers. Oral commissure symmetry at rest was better for hypoglossal transfer (2.22 ± 1.6 mm vs. 3.62 ± 2.7 mm, p = 0.047). The composite Sunnybrook Facial Nerve Grading Scale was better for masseteric transfer (47.7 ± 7.4 vs. 33.0 ± 6.4, p < 0.001). Time to first movement (in months) was significantly faster in masseteric transfer (4.6 ± 2.6 vs. 6.3 ± 1.3, p < 0.001). Adverse effects were rare (<5%) for both procedures. Conclusions: Both nerve transfer techniques are effective for facial reanimation, and the surgeon should consider the nuanced differences in selecting the correct procedure for each patient.