[Clinical analysis of transcranial facial nerve bridging with interpositional graft for the treatment of facial nerve injury].

Objective:To retrospectively analyze the effectiveness of transcranial facial nerve bridging in the treatment of facial nerve dysfunction. Methods:A retrospective analysis was conducted on 27 patients with facial nerve dysfunction who underwent transcranial facial nerve bridging at the Eye, Ear, Nose, and Throat Hospital affiliated with Fudan University from 2017 to 2022. The main collected data includes the patient's age, gender, primary lesion, damaged location, interval from facial paralysis to surgery, and preoperative and postoperative House-Brackmann（HB） scale for facial nerve function. Statistical comparisons were made between the average HB level of patients before and after surgery. Results:A total of 27 patients included 17 males and 10 females. The average age of patients during surgery is（42.50±3.38） years old. Primary lateral skull base diseases include trauma（n=3）, tumors（n=22）, and infections（n=2）. The duration of facial paralysis varies from 6 months to 5 years. Statistics analysis has found that the average postoperative HB score of patients who underwent transcranial facial nerve bridging was significantly lower at（3.750 ± 0.183） compared to preoperative（4.875±0.168）. The proportion of patients with good facial nerve function increased significantly from 7.4% before surgery to 42.9% after surgery. Conclusion:Transcranial facial nerve bridging surgery with interpositional graft has a significant effect on improving facial nerve function in patients with facial nerve injury. Further research is still needed to evaluate the long-term effectiveness of this surgery, to determine the optimal patient selection criteria and postoperative rehabilitation strategies.

[Clinical characteristics and prognosis of two anastomosis techniques in the treatment of facial nerve defects].

Objective:To investigate the characteristics and prognosis of two anastomosis techniques in repairing facial nerve defects. Methods:A retrospective analysis was conducted on 30 patients who underwent facial nerve anastomosis（direct or rerouting） for facial nerve defects in our department from January 2012 to December 2021. Among them, 21 were male and 9 were female, with an average age of（37.53±11.33） years, all with unilateral onset. Preoperative House-Brackmann（H-B） facial nerve function grades were Ⅳ in 2 cases, Ⅴ in 9 cases, and Ⅵin 19 cases. The duration of facial paralysis before surgery was within 6 months in 21 cases, 6-12 months in 6 cases, and over 1 year in 3 cases. The causes of facial paralysis included 14 cases of cholesteatoma, 6 cases of facial neurioma, 6 cases of trauma, and 4 cases of middle ear surgery injury. Surgical approaches included 9 cases of the middle cranial fossa approach, 8 cases of labyrinthine-otic approach, 7 cases of mastoid-epitympanum approach, and 6 cases of retroauricular lateral neck approach. Results:All patients were followed up for more than 2 years. The direct anastomosis was performed in 10 cases: 6 cases with defects located in the extratemporal segment and 4 cases in the tympanic segment. Rerouting anastomosis was performed in 20 cases: 11 cases with defects located in the labyrinthine-geniculate ganglion, 4 cases from the internal auditory canal to the geniculate ganglion, 3 cases in the internal auditory canal, and 2 cases in the horizontal-pyramid segment. Postoperative H-B facial nerve grades were Ⅱ in 2 cases, Ⅲ in 20 cases, and Ⅳ in 8 cases, with 73.3%（22/30） of patients achieving H-B grade Ⅲ or better. Conclusion:Both direct and rerouting anastomosis techniques can effectively repair facial nerve defects, with no significant difference in efficacy between the two techniques. Most patients can achieve H-B grade Ⅲ or better facial nerve function recovery. Preoperative facial nerve function and duration of facial paralysis are the main prognostic factors affecting the outcome of facial nerve anastomosis.

[Diagnosis and treatment of 68 cases of traumatic facial nerve paralysis].

Objective:To summarize the clinical characteristics and therapeutic effect of traumatic facial nerve palsy. Methods:Sixty-eight cases of traumatic facial nerve palsy were retrospectively analyzed from January 2015 to May 2023. Results:The median course of disease was 33 days. The facial nerve function of the patients was grade HB-Ⅱin 2 cases, grade HB-Ⅲ in 4 cases, grade HB-Ⅳin 16 cases, grade HB-Ⅴ in 37 cases（38 ears）, and grade HB-Ⅵ in 9 cases. 42 cases occurred immediately after injury and 26 cases were delayed. CT examination of temporal bone revealed longitudinal fractures in 51 cases（52 ears） , transverse fractures in 6 cases and mixed fractures in 4 cases. No definite temporal bone fracture was found in the remaining 7 cases. The segments of facial nerve injury in 49 cases（50 ears） were geniculate ganglion and adjacent, in 7 cases were vertical segment, in 7 cases were horizontal segment, in 2 cases were horizontal segment and vertical segment; and the other 3 cases could not be evaluated. Conservative treatment with glucocorticoids was used in 23 ears and surgery was used in 46 ears. Patients were followed up 6-24 months after treatment, including 20 cases of grade HB-Ⅰ, 19 cases of grade HB-Ⅱ, 23 cases（24 ears） of grade HB-Ⅲ, 4 cases of grade HB-Ⅳ, and 1 case of grade HB-Ⅴ.One patient was lost to follow-up. After treatment, the facial nerve function of patients was significantly improved（P<0.05）, and there were significant differences between conservative treatment group and surgical treatment group in the course of facial nerve palsy, the ratio of facial palsy immediately after injury, the nerve function before treatment and the nerve function after treatment（P<0.05）. There were no significant differences in age, sex, hearing condition, temporal bone fracture, facial nerve injury segment and rate of favorable neurologic outcomes（P>0.05）. The comparison of patients with neurodegeneration rate>90% and ≤90% showed that the facial nerve function of patients with neurodegeneration rate>90% before treatment was significantly worse（P<0.05）, but there was no significant difference between the facial nerve function after treatment（P>0.05）. There was no significant difference in facial nerve function between middle fossa approach group and mastoid approach group（P>0.05）. Conclusion:Patients with traumatic facial nerve palsy should be evaluated individually. Patients with mild facial nerve palsy, low neurodegeneration rate and short course of disease can be treated conservatively and followed up closely. Patients with severe facial nerve palsy, high neurodegeneration rate and more than 6 weeks of disease can be actively considered surgery. Good prognosis can be obtained by correct evaluation and treatment.

[MiR-132-3p negatively regulates CAMTA1 to promote Schwann cell proliferation and migration and alleviates I-125 seeds-induced exacerbation of facial nerve injury in rats].

OBJECTIVE: To investigate the regulatory effect of miR-132-3p on calmodulin-binding transcription activator 1 (CAMTA1) and Schwann cell activity in rats with facial nerve injury (FNI) treated with I-125 seeds. METHODS: Rat Schwann cells were irradiated with I-125 seeds and transfected with miR-132-3p mimic, miR-132-3p inhibitor or sh-CAMTA1. The expressions of S100B and ß-tubulin Ⅲ in the cells were detected with immunofluorescence assay, and the expressions of miR-132-3p and CAMTA1 protein were determined using RT-qPCR and Western blotting, respectively. EdU staining and Transwell assay were used to evaluate the changes in cell proliferation and migration ability. In a rat model of FNI, I-125 seeds were implanted into the facial tissues near the facial nerve 2 weeks before modeling, and miR-132-3p mimic was injected subcutaneously in the face after modeling. The pathologies of the facial nerve was assessed by HE, LFB and immunofluorescence staining. The targeting relationship between miR-132-3p and CAMTA1 was verified using StarBase v2.0 database and dual-luciferase reporter assay. RESULTS: Rat Schwann cells showed high expressions of S100B and ß-tubulin Ⅲ. I-125 seeds radiation significantly decreased miR-132-3p expression and repressed proliferation and migration of the cells (P < 0.001). Overexpression of miR-132-3p or CAMTA1 knockdown obviously enhanced proliferation and migration of the Schwann cells, while miR-132-3p knockdown produced the opposite effect. MiR-132-3p negatively regulated CAMTA1 expression. In the rat models of FNI, miR-132-3p injection significantly inhibited CAMTA1 expression and attenuated I-125 seeds-induced exacerbation of FNI. CONCLUSION: Overexpression of miR-132-3p suppresses CAMTA1 expression and promotes Schwann cell proliferation and migration to alleviate I-125 seeds-induced exacerbation of FNI in rats.

Enhancing nerve regeneration in infraorbital nerve injury rat model: effects of vitamin B complex and photobiomodulation.

Orofacial nerve injuries may result in temporary or long-term loss of sensory function and decreased quality of life in patients. B vitamins are required for DNA synthesis and the repair and maintenance of phospholipids. In particular, vitamins B1, B6, and B12 are essential for neuronal function. Deficiency in vitamin B complex (VBC) has been linked to increased oxidative stress, inflammation and demyelination. Photobiomodulation (PBM) has antioxidant activity and is neuroprotective. In addition, a growing literature attests to the positive effects of PBM on nerve repair. To assess the effect of PBM and VBC on regenerative process we evaluated the expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), myelin basic protein (MBP), laminin and neurofilaments (NFs) using Western blotting to identify regenerative pattern after chronic constriction injury of the infraorbital nerve (CCI IoN) treated by PBM, VBC or its combination. After CCI IoN, the rats were divided into six groups naive, sham, injured (CCI IoN), treated with photobiomodulation (904 nm, 6.23 J/cm2, CCI IoN + PBM), treated with VBC (containing B1, B6 and B12) 5 times, CCI IoN + VBC) and treated with PBM and VBC (CCI IoN + VBC + PBM). The treatments could revert low expression of BDNF, MBP and laminin. Also reverted the higher expression of neurofilaments and enhanced expression of NGF. PBM and VBC could accelerate injured infraorbital nerve repair in rats through reducing the expression of neurofilaments, increasing the expression of BDNF, laminin and MBP and overexpressing NGF. These data support the notion that the use of PBM and VBC may help in the treatment of nerve injuries. This finding has potential clinical applications.

GFP-labeled Schwann cell-like cells derived from hair follicle epidermal neural crest stem cells promote the acellular nerve allografts to repair facial nerve defects in rats.

BACKGROUND: Acellular nerve allografts (ANAs) have been successfully applied to bridge facial nerve defects, and transplantation of stem cells may enhance the regenerative results. Up to now, application of hair follicle epidermal neural crest stem cell-derived Schwann cell-like cells (EPI-NCSC-SCLCs) combined with ANAs for bridging facial nerve defects has not been reported. METHODS: The effect of ANAs laden with green fluorescent protein (GFP)-labeled EPI-NCSC-SCLCs (ANA + cells) on bridging rat facial nerve trunk defects (5-mm-long) was detected by functional and morphological examination, as compared with autografts and ANAs, respectively. RESULTS: (1) EPI-NCSC-SCLCs had good compatibility with ANAs in vitro. (2) In the ANA + cells group, the GFP signals were observed by in vivo imaging system for small animals within 8 weeks, and GFP-labeled EPI-NCSC-SCLCs were detected in the tissue slices at 16 weeks postoperatively. (3) The facial symmetry at rest after surgery in the ANA + cells group was better than that in the ANA group (p < 0.05), and similar to that in the autograft group (p > 0.05). The initial recovery time of vibrissal and eyelid movement in the ANA group was 2 weeks later than that in the other two groups. (4) The myelinated fibers, myelin sheath thickness and diameter of the axons of the buccal branches in the ANA group were significantly worse than those in the other two groups (P < 0.05), and the results in the ANA + cells group were similar to those in the autograft group (p > 0.05). CONCLUSIONS: EPI-NCSC-SCLCs could promote functional and morphological recovery of rat facial nerve defects, and GFP labeling could track the transplanted EPI-NCSC-SCLCs in vivo for a certain period of time. These may provide a novel choice for clinical treatment of peripheral nerve defects.

Appropriate dosage, timing, and site of intramuscular injections of brain-derived neurotrophic factor (BDNF) promote motor recovery after facial nerve injury in rats.

INTRODUCTION/AIMS: Daily intramuscular injections of fibroblast growth factor 2 (FGF2) but not of brain-derived neurotrophic factor (BDNF) significantly improve whisking behavior and mono-innervation of the rat levator labii superioris (LLS) muscle 56 days after buccal nerve transection and suture (buccal-buccal anastomosis, BBA). We explored the dose-response of BDNF, FGF2, and insulin growth factor 2 (IGF2) on the same parameters, asking whether higher doses of BDNF would promote recovery. METHODS: After BBA, growth factors were injected (30 µL volume) daily into the LLS muscle over 14, 28, or 56 days. At 56 days, video-based motion analysis of vibrissal whisking was performed and the extent of mono- and poly-reinnervation of the reinnervated neuromuscular junctions (NMJs) of the muscle determined with immunostaining of the nerve with ß-tubulin and histochemical staining of the endplates with Alexa Fluor 488-conjugated α-bungarotoxin. RESULTS: The dose-response curve demonstrated significantly higher whisking amplitudes and corresponding increased mono-innervation of the NMJ in the reinnervated LLS muscle at concentrations of 20-30 µg/mL BDNF administered daily for 14-28 days after BBA surgery. In contrast, high doses of IGF2 and FGF2, or doses of 20 and 40 µg/mL of BDNF administered for 14-56 days had no effect on either whisking behavior or in reducing poly-reinnervation of endplates in the muscle. DISCUSSION: These data suggest that the re-establishment of mono-innervation of whiskerpad muscles and the improved motor function by injections of BDNF into the paralyzed vibrissal musculature after facial nerve injury have translation potential and promote clinical application.

[A sampling survey of intraoperative facial nerve monitoring in China].

Objective: This study aims to investigate the current application and the level of knowledge of intraoperative facial nerve monitoring among medical staff in China. Methods: A comprehensive online questionnaire was conducted among medical professionals across different regions in China from October 2022 to February 2023. The survey exclusively targeted departments specializing in otolaryngology, head and neck surgery, neurosurgery, and oral and maxillofacial surgery. The questionnaire covered various aspects including general information, intraoperative facial nerve monitoring practices, training history, indications for monitoring, parameters used during monitoring procedures, as well as factors influencing its implementation. Results: A total of 417 participants from 31 provincial, municipal, and autonomous regions were included. Intraoperative facial nerve monitoring was found to be implemented in 227 (54.4%,227/417) repondents of 53 institutions (24.9%, 53/213). The top three indications for implementing this technique were acoustic neuroma, parotid gland surgery, and modified middle ear surgery (mastoidectomy). Herein 81.1%(184/227) medical staff involved in intraoperative facial nerve monitoring had received relevant training, 57.3%(130/227)-92.1%(209/227) reported a lack of clear description regarding recording thresholds, stimulation currents/frequencies/wave widths. Conclusion: The majority of the institutions surveyed have not yet adopted intraoperative facial nerve monitoring. Furthermore, significant gaps concerning the procedure exist. It is imperative to establish standards or guidelines to promote its better development and application.

The involvement of Neuregulin-1 in the process of facial nerve injury repair through the utilization of dental pulp stem cells.

BACKGROUND: Facial nerve injury often results in poor prognosis due to the challenging process of nerve regeneration. Neuregulin-1, a human calmodulin, is under investigation in this study for its impact on the reparative capabilities of Dental Pulp Stem Cells (DPSCs) in facial nerve injury. METHODS: Lentivirus was used to transfect and construct Neuregulin-1 overexpressed DPSCs. Various techniques assessed the effects of Neuregulin-1: osteogenic induction, lipid induction, Reverse Transcription Polymerase Chain Reaction, Western Blot, Cell Counting Kit-8 assay, wound healing, immunofluorescence, Phalloidin staining, nerve stem action potential, Hematoxylin-eosin staining, transmission electron microscopy, and immunohistochemistry. RESULTS: Neuregulin-1 effectively enhanced the proliferation, migration, and cytoskeletal rearrangement of DPSCs, while simultaneously suppressing the expression of Ras homolog gene family member A (RhoA) and Microfilament actin (F-actin). These changes facilitated the neural differentiation of DPSCs. Additionally, in vivo experiments showed that Neuregulin-1 expedited the restoration of action potential in the facial nerve trunk, increased the thickness of the myelin sheath, and stimulated axon regeneration. CONCLUSION: Neuregulin-1 has the capability to facilitate the repair of facial nerve injuries by promoting the regenerative capacity of DPSCs. Thus, Neuregulin-1 is a significant potential gene in the reparative processes of nerve damage.

Porous Organic Materials in Tissue Engineering: Recent Advances and Applications for Severed Facial Nerve Injury Repair.

The prevalence of facial nerve injury is substantial, and the restoration of its structure and function remains a significant challenge. Autologous nerve transplantation is a common treatment for severed facial nerve injury; however, it has great limitations. Therefore, there is an urgent need for clinical repair methods that can rival it. Tissue engineering nerve conduits are usually composed of scaffolds, cells and neurofactors. Tissue engineering is regarded as a promising method for facial nerve regeneration. Among different factors, the porous nerve conduit made of organic materials, which has high porosity and biocompatibility, plays an indispensable role. This review introduces facial nerve injury and the existing treatment methods and discusses the necessity of the application of porous nerve conduit. We focus on the application of porous organic polymer materials from production technology and material classification and summarize the necessity and research progress of these in repairing severed facial nerve injury, which is relatively rare in the existing articles. This review provides a theoretical basis for further research into and clinical interventions on facial nerve injury and has certain guiding significance for the development of new materials.

Ocular-oral synkinesis caused by partial injury of the zygomatic and buccal branches of the facial nerve after mid-face trauma.

BACKGROUND: Facial nerve paralysis induced by acute traumatic facial nerve injuries limited to the zygomatic and buccal branches shows unique complications, such as strong co-contractions of the lower facial muscles around the lips during voluntary blinking (ocular-oral synkinesis). We investigated the characteristics of facial complications after facial nerve injury in the mid-face area and reported the treatment results. METHODS: A total of 21 patients with facial nerve injuries to the zygomatic and/or buccal branches were evaluated for the degree of facial synkinesis and mouth asymmetry. Patients with mild-to-moderate symptoms were treated using physical rehabilitation therapy combined with botulinum toxin (Botox) injection, and patients with severe or uncontrolled symptoms were treated using surgical therapy. RESULTS: Initial/final mean synkinesis scores and mouth asymmetry degrees were 2.17/1.75 and 0.85/0.66 in the physical therapy group and 3.11/0.78 and 2.41/-0.31 in the surgery group, respectively. Physical therapy with Botox injection alone did not show significant improvements in synkinetic symptoms of the patients with mild-to-moderate synkinesis (p > 0.05), whereas surgical therapy resulted in significant improvements in synkinesis and mouth asymmetry (p < 0.05). CONCLUSIONS: Surgical treatment is an effective adjustment procedure for the management of facial complications in patients with severe or uncontrolled synkinesis after facial nerve injury to the mid-face area.

Electroacupuncture Promotes Functional Recovery after Facial Nerve Injury in Rats by Regulating Autophagy via GDNF and PI3K/mTOR Signaling Pathway.

OBJECTIVE: To explore the mechanism of electroacupuncture (EA) in promoting recovery of the facial function with the involvement of autophagy, glial cell line-derived neurotrophic factor (GDNF), and phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway. METHODS: Seventy-two male Sprague-Dawley rats were randomly allocated into the control, sham-operated, facial nerve injury (FNI), EA, EA+3-methyladenine (3-MA), and EA+GDNF antagonist groups using a random number table, with 12 rats in each group. An FNI rat model was established with facial nerve crushing method. EA intervention was conducted at Dicang (ST 4), Jiache (ST 6), Yifeng (SJ 17), and Hegu (LI 4) acupoints for 2 weeks. The Simone's 10-Point Scale was utilized to monitor the recovery of facial function. The histopathological evaluation of facial nerves was performed using hematoxylin-eosin (HE) staining. The levels of Beclin-1, light chain 3 (LC3), and P62 were detected by immunohistochemistry (IHC), immunofluorescence, and reverse transcription-polymerase chain reaction, respectively. Additionally, IHC was also used to detect the levels of GDNF, Rai, PI3K, and mTOR. RESULTS: The facial functional scores were significantly increased in the EA group than the FNI group (P<0.05 or P<0.01). HE staining showed nerve axons and myelin sheaths, which were destroyed immediately after the injury, were recovered with EA treatment. The expressions of Beclin-1 and LC3 were significantly elevated and the expression of P62 was markedly reduced in FNI rats (P<0.01); however, EA treatment reversed these abnormal changes (P<0.01). Meanwhile, EA stimulation significantly increased the levels of GDNF, Rai, PI3K, and mTOR (P<0.01). After exogenous administration with autophagy inhibitor 3-MA or GDNF antagonist, the repair effect of EA on facial function was attenuated (P<0.05 or P<0.01). CONCLUSIONS: EA could promote the recovery of facial function and repair the facial nerve damages in a rat model of FNI. EA may exert this neuroreparative effect through mediating the release of GDNF, activating the PI3K/mTOR signaling pathway, and further regulating the autophagy of facial nerves.

Subclassification of Koos grade 4 vestibular schwannoma: insights into tumor morphology for predicting postoperative facial nerve function.

OBJECTIVE: Koos grade 4 vestibular schwannoma (KG4VS) is a large tumor that causes brainstem displacement and is generally considered a candidate for surgery. Few studies have examined the relationship between morphological differences in KG4VS other than tumor size and postoperative facial nerve function. The authors have developed a landmark-based subclassification of KG4VS that provides insights into the morphology of this tumor and can predict the risk of facial nerve injury during microsurgery. The aims of this study were to morphologically verify the validity of this subclassification and to clarify the relationship of the position of the center of the vestibular schwannoma within the cerebellopontine angle (CPA) cistern on preoperative MR images to postoperative facial nerve function in patients who underwent microsurgical resection of a vestibular schwannoma. METHODS: In this paper, the authors classified KG4VSs into two subtypes according to the position of the center of the KG4VS within the CPA cistern relative to the perpendicular bisector of the porus acusticus internus, which was the landmark for the subclassification. KG4VSs with ventral centers to the landmark were classified as type 4V, and those with dorsal centers as type 4D. The clinical impact of this subclassification on short- and long-term postoperative facial nerve function was analyzed. RESULTS: In this study, the authors retrospectively reviewed patients with vestibular schwannoma who were treated surgically via a retrosigmoid approach between January 2010 and March 2020. Of the 107 patients with KG4VS who met the inclusion criteria, 45 (42.1%) were classified as having type 4V (KG4VSs with centers ventral to the perpendicular bisector of the porous acusticus internus) and 62 (57.9%) as having type 4D (those with centers dorsal to the perpendicular bisector). Ventral extension to the perpendicular bisector of the porus acusticus internus was significantly greater in the type 4V group than in the type 4D group (p < 0.001), although there was no significant difference in the maximal ventrodorsal diameter. The rate of preservation of favorable facial nerve function (House-Brackmann grades I and II) was significantly lower in the type 4V group than in the type 4D group in terms of both short-term (46.7% vs 85.5%, p < 0.001) and long-term (82.9% vs 96.7%, p = 0.001) outcomes. Type 4V had a significantly negative impact on short-term (OR 7.67, 95% CI 2.90-20.3; p < 0.001) and long-term (OR 6.05, 95% CI 1.04-35.0; p = 0.045) facial nerve function after surgery when age, tumor size, and presence of a fundal fluid cap were taken into account. CONCLUSIONS: The authors have delineated two different morphological subtypes of KG4VS. This subclassification could predict short- and long-term facial nerve function after microsurgical resection of KG4VS via the retrosigmoid approach. The risk of postoperative facial palsy when attempting total resection is greater for type 4V than for type 4D. This classification into types 4V and 4D could help to predict the risk of facial nerve injury and generate more individualized surgical strategies for KG4VSs with better facial nerve outcomes.

Mandibular condylar fractures: a 5-year retrospective analysis comparing open versus closed reduction.

BACKGROUND: Mandibular fractures are common facial fractures, and contemporary management of mandibular condylar fractures is controversial. The purpose of this study was to compare the outcomes of patients who sustained a mandibular condylar fracture between 2016 and 2020, who were managed by either open or closed techniques. The outcomes of this study were: post-operative facial nerve function, occlusion, and maximal mouth opening. METHODS: This study is a retrospective multicentre cohort study which assessed clinical records for 246 patients with mandibular condyle fractures in three hospitals in Perth, Western Australia. The primary outcome measure was changes in post-operative facial nerve function. RESULTS: One hundred and thirty-two patients underwent open reduction and internal fixation (ORIF), and 114 patients had closed management. The overall rate of temporary facial nerve injury following ORIF was 3.28%. The overall rate of permanent facial nerve injury was 0.82%. Sialocoele occurred in 2.46% of all patients who underwent ORIF. 6.14% of patients had persisting malocclusion across both groups. There was a statistically significant association between the degree of fragment shortening and facial nerve injury (P = 0.0063), with more facial nerve changes in the group with 5 mm or greater of fragment shortening. CONCLUSIONS: There is still significant debate over the management of mandibular condylar injuries. This study demonstrates a similar rate of temporary and permanent facial nerve injury as previously described, as well as a similar rate of sialocoele occurrence. Further prospective studies may provide clarity about important characteristics that will help guide decision making for mandibular condylar fractures.

Mesenchymal Stem Cell-Derived Exosomes Promote Recovery of The Facial Nerve Injury through Regulating Macrophage M1 and M2 Polarization by Targeting the P38 MAPK/NF-Κb Pathway.

Facial nerve (FN) injury seriously affects human social viability and causes a heavy economic and social burden. Although mesenchymal stem cell-derived exosomes (MSC-Exos) promise therapeutic benefits for injury repair, there has been no evaluation of the impact of MSC-Exos administration on FN repair. Herein, we explore the function of MSC-Exos in the immunomodulation of macrophages and their effects in repairing FN injury. An ultracentrifugation technique was used to separate exosomes from the MSC supernatant. Administrating MSC-Exos to SD rats via local injection after FN injury promoted axon regeneration and myelination and alleviated local and systemic inflammation. MSC-Exos facilitated M2 polarization and reduced the M1-M2 polarization ratio. miRNA sequencing of MSC-Exos and previous literature showed that the MAPK/NF-κb pathway was a downstream target of macrophage polarization. We confirmed this hypothesis both in vivo and in vitro. Our findings show that MSC-Exos are a potential candidate for treating FN injury because they may have superior benefits for FN injury recovery and can decrease inflammation by controlling the heterogeneity of macrophages, which is regulated by the p38 MAPK/NF-κb pathway.

An Artificial Neural Network Model for Predicting Postoperative Facial Nerve Outcomes After Vestibular Schwannoma Surgery.

BACKGROUND AND OBJECTIVES: The emergence of machine learning models has significantly improved the accuracy of surgical outcome predictions. This study aims to develop and validate an artificial neural network (ANN) model for predicting facial nerve (FN) outcomes after vestibular schwannoma (VS) surgery using the proximal-to-distal amplitude ratio (P/D) along with clinical variables. METHODS: This retrospective study included 71 patients who underwent VS resection between 2018 and 2022. At the end of surgery, the FN was stimulated at the brainstem (proximal) and internal acoustic meatus (distal) and the P/D was calculated. Postoperative FN function was assessed using the House-Brackmann grading system at discharge (short-term) and after 9-12 months (long-term). House-Brackmann grades I-II were considered good outcome, whereas grades III-VI were considered fair/poor. An ANN model was constructed, and the performance of the model was evaluated using the area under the ROC curve for internal validation and accuracy, sensitivity, specificity, and positive and negative predictive values for external validation. RESULTS: The short-term FN outcome was grades I-II in 57.7% and grades III-VI in 42.3% of patients. Initially, a model using P/D had an area under the curve of 0.906 (internal validation) and an accuracy of 89.1% (95% CI: 68.3%-98.8%) (external validation) for predicting good vs fair/poor short-term FN outcomes. The model was then refined to include only muscles with a P/D with a proximal latency between 6 and 8 ms. This improved the accuracy to 100% (95% CI: 79%-100%). Integrating clinical variables (patient's age, tumor size, and preoperative HB grade) in addition to P/D into the model did not significantly improve the predative value. A model was then created to predict the long-term FN outcome using P/D with latencies between 6 and 8 ms and had an accuracy of 90.9% (95% CI: 58.7%-99.8%). CONCLUSION: ANN models incorporating P/D can be a valuable tool for predicting FN outcomes after VS surgery. Refining the model to include P/D with latencies between 6 and 8 ms further improves the model's prediction. A user-friendly interface is provided to facilitate the implementation of this model.

The "low preauricular" transmasseteric anteroparotid (TMAP) technique as a standard way to treat extracapsular condylar fractures.

Condylar fracture treatment is a debated topic among maxillofacial surgeons. Various surgical techniques are used today, each one with advantages and disadvantages. The aim of this study is to present and evaluate our technique adopted for treatment of any type of extracapsular condylar fractures. Between 2020 and 2022, 16 condylar fractures were treated. In two patients with bilateral condylar fractures, the present technique was compared to the mini-retromandibular approach. All the patients were checked for clinical and radiological outcomes, facial nerve injury, scar visibility and presence of salivary complications. Dental occlusion was always restored, and facial nerve damage or salivary disorders were not observed. The skin incision, limited to the caudal two-thirds of the auricle, made the scar almost invisible and greatly improved the surgical field in the condylar neck area, facilitating the treatment. The proposed technique provides easier internal fixation for both neck and base condylar fractures with good cosmetic results, ensuring better protection of the facial nerve and parotid gland. The surgical technique described has not shown disadvantages in terms of operational difficulty, results, and complications. This novel surgical technique could represent a new choice in the treatment of extracapsular condylar fractures, although further studies are needed to support this new proposal.

Application of diffusion tensor imaging of the facial nerve in preoperative planning for large vestibular schwannoma: a systematic review.

The accurate identification and preservation of the facial nerve (FN) during vestibular schwannoma (VS) surgery is crucial for maintaining facial function. Investigating the application of diffusion tensor imaging (DTI) in preoperative planning for large VS surgery is provided. PubMed, Cochrane Library, Science Direct, ISI Web of Science, Embase, and additional sources were searched to identify cohort studies about the preoperative DTI usage for the FN tracking before large VS (≥ 2.5 cm) surgery published between 1990 and 2023. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed; the Newcastle-Ottawa Scale was used to assess the risk of bias and to evaluate limitations based on selection/outcome biases. A total of 8 publications yielding 149 VS (mean size 3.66 ± 0.81 cm) were included. Surgical concordance with preoperative DTI FN tracking was 91.67% (range 85-100%). Overall DTI reliability was 88.89% (range 81.81-95.83%). Larger tumor size predicted either DTI inaccurate finding or complete DTI failure (p = 0.001). VS size above > 3.5 cm was associated with a higher risk of DTI failure (p = 0.022), with a higher risk of inaccurate DTI finding preoperatively (p = 0.033), and with a higher House-Brackman score postoperatively (p = 0.007). Application of DTI in larger VS surgery is a valuable FN identification along with electrophysiological monitoring and neuronavigation, therefore also in its preservation and in lowering risk of complications. DTI represents a valuable adjunct to electrophysiological monitoring and neuronavigation in FN identification, applicable not only for smaller, but also larger VS.

Optimizing Facial Function in Patients With High-Risk Recurrent Pleomorphic Adenoma and a History of Facial Nerve Injury.

BACKGROUND: Parotid pleomorphic adenoma (PA) patients present significant diagnostic and surgical challenges rendering them high risk for facial nerve injury. Recurrent PA patients often present with history of facial nerve injury or previous reanimations making salvage of the facial nerve or previous reanimations significantly more complex. The study aim is to share our experience with this high risk for facial nerve injury population and review the literature. METHODS: Adult patients with recurrent PA and history of facial nerve injury with at least 3 months of follow-up were analyzed for demographics, facial palsy history, previous head and neck surgeries, previous facial paralysis reconstruction, preoperative imaging, surgical approach, and postoperative outcomes. RESULTS: Four female patients were identified with an average age of 62 years. All patients underwent an initial protective dissection of the facial nerve or previous reanimation reconstruction by the facial nerve reconstructive team followed by the extirpative team. The average number of previous head and neck surgeries was 5, the number of recurrences was 2, and follow-up was 20 months. Half had prior dynamic facial reanimation. Two patients underwent complete preextirpative dissection of the facial nerve resulting in neuropraxia, which recovered completely after an average of 143 days. A third patient presented with 2 recurrences, both during and after reanimation with a dually innervated free functional muscle transfer. The reconstruction was salvaged, and motion was achieved. A fourth patient presented with benign preoperative findings, but intraoperative findings confirmed malignancy, necessitating facial nerve sacrifice, followed by immediate intratemporal grafting of the facial nerve and masseteric nerve transfer. Motion appeared 139 days postoperatively. CONCLUSIONS: A multidisciplinary effort should be implemented in this high risk for facial nerve injury population with the primary goal of protecting the facial nerve or any previous reanimation procedures, yet with preparedness to apply any reconstructive strategy based on intraoperative findings.