Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery

Endoscopic approach to geniculate ganglion: a multicentric experience

PURPOSE

A variety of lesions could arise from the GG area, or extend into this region from adjacent sites. The management of perigeniculate lesions includes observation, surgery, and radiation, according to the nature, the size of the lesion, and the accompanying symptoms. Preliminary experiences on the exclusive transcanal endoscopic approach to the GG area have shown safety and feasibility avoiding of any postauricular incision, or brain manipulation. The experience from two referral centers on patients treated for a GG lesion with a totally endoscopic approach is herein reported.

METHODS

Data about patients who underwent exclusive endoscopic approach to the GG area at the Otolaryngology Departments of the University Hospitals of Modena and Bologna between May 2017 and February 2022 were retrospectively collected.

RESULTS

The total number of patients included in our study was 11. 10 patients (91%) had progressive unilateral facial paralysis and 1 patient (11%) presented with chronic otorrhea. The mean largest diameter of the treated lesions was of 8 mm. The resection was extended to the fundus of the IAC in 2 patients (expanded approach). The remaining 9 patients (82%) underwent partial ossicular replacement prosthesis (PORP). No major complications occurred. Facial nerve outcomes were good in all patients and the mean ABG worsened from 12 dB pre-operatively to 22 dB post-operatively.

CONCLUSIONS

The exclusively endoscopic approach to GG lesions represents a viable alternative to traditional microscopic approaches and may be included in the armamentarium of ear surgeons.

Sural nerve grafts in subacute facial nerve injuries: a report of two cases

Because facial nerve injuries affect the quality of life, leaving them untreated can have devastating effects. The number of patients with traumatic and iatrogenic facial nerve paralysis is considerably high. Early detection and prompt treatment during the acute injury phase are crucial, and immediate surgical treatment should be considered when complete facial nerve injury is suspected. Symptom underestimation by patients and clinical misdiagnosis may delay surgical intervention, which may negatively affect outcomes and in some cases, impair the recovery of the injured facial nerve. Here, we report two cases of facial nerve injury that were treated with nerve grafts during the subacute phase. In both cases, subacute facial nerve grafting achieved significant improvements. These cases highlight surgical intervention in the subacute phase using nerve grafts as an appropriate treatment for facial nerve injuries.

A Rare Case of a Fenestrated Retromandibular Vein Lying Lateral to the Facial Nerve Bifurcation

Facial nerve integrity is the cornerstone of parotid surgery. Although a variety of anatomical landmarks have been employed, facial nerve injury still happens causing devastating functional and cosmetic sequelae. The retromandibular vein is considered one of the most consistent structures lying just deep into the facial nerve. In our cadaveric study, we found a fenestrated retromandibular vein lying superficial to the bifurcation of the facial nerve. This rare anatomical variation would have been a challenge for a hypothetic parotidectomy. Surgeons should be aware of both anterograde and retrograde dissection of the facial nerve and choose the most proper approach to preserve the integrity of the facial nerve.

Primary Neurorraphy of the Frontotemporal Branch of the Facial Nerve in Pediatric Patients

LEVEL OF EVIDENCE

Level III-case-control study.

Biodegradable Nerve Guide with Glial Cell Line-Derived Neurotrophic Factor Improves Recovery After Facial Nerve Injury in Rats

Background: Bioengineered nerve guides with glial cell line-derived neurotrophic factor (GDNF) support recovery after facial nerve injury by acting as regenerative scaffolds. Objective: To compare functional, electrophysiological, and histological outcomes after repair of rat facial nerve transection in control, empty nerve guide, and nerve guide with GDNF conditions. Methods: Rats underwent transection and primary repair of the buccal branch of the facial nerve and were divided into (1) transection and repair only, (2) transection and repair augmented with empty guide, (3) transection and repair augmented with GDNF-guide groups. Weekly measurements of the whisking movements were recorded. At 12 weeks, compound muscle action potentials (CMAPs) at the whisker pad were assessed, and samples were collected for histomorphometric analysis. Results: Rats in GDNF-guide group displayed the earliest peak in normalized whisking amplitude. CMAPs were significantly higher after GDNF-guide placement. Mean fiber surface area of the target muscle, axonal count of the injured branch, and the number of Schwann cells were highest with GDNF guides. Conclusion: The biodegradable nerve guide containing double-walled GDNF microspheres enhanced recovery after facial nerve transection and primary repair.

Study on the Influencing Factors of Short-Term Recovery of Neurological Symptoms after Carotid Body Tumor Resection

OBJECTIVE

To compare the differences in the short-term recovery from neurological symptoms (SRN) (≤ 6 months) and clinical characteristics of patients with different Shamblin classifications carotid body tumor (CBT) resection and to analyze the risk factors affecting SRN after surgery.

METHODS

Patients who underwent CBT resection between June 2018 and September 2022 were recruited. Perioperative factors and indicators of the nature of the tumor were recorded. The risk factors affecting SRN after CBT resection were analyzed using logistic regression analysis.

RESULTS

Eighty-five patients (43.86 ± 12.7 years, 46 females) were included, 40 (47.06%) of whom exhibited SRN. Univariate logistic regression showed that preoperative symptoms, surgical side, bilateral posterior communicating artery (PcoA) opening, some indicators of tumor size, operative/anesthesia time, and Shamblin III classification were correlated with postoperative neurological prognosis (all p < 0.05). After adjusting for confounders, preoperative symptoms (OR, 5.072; 95% CI 1.027-25.052; p = 0.046), surgical side (OR, 0.025; 95% CI 0.003-0234; p = 0.001), bilateral PcoA opening (OR, 22.671; 95% CI 2.549-201.666; p = 0.005), distance from the tip of the C2 dens to the superior aspect (dens-CBT) (OR, 0.918; 95% CI 0.858-0.982; p = 0.013) and Shamblin III classification (OR, 28.488; 95% CI 1.986-408.580; p = 0.014) were correlated with postoperative neurological symptom recovery.

CONCLUSION

Preoperative symptoms, surgical side (right), bilateral PcoA opening, a short dens-CBT and Shamblin III classification are risk factors affecting SRN after CBT resection. Early resection is recommended for small-volume CBTs without neurovascular compression or invasion to obtain SRN.

Anatomical knowledge of zygomatico-buccal plexus in a cadaveric study

The details of the facial nerve pattern were clearly explained in the parotid gland (PG), lateral area of the face, and periorbital areas to prevent the unexpected outcome of medical intervention. However, it remains unclear whether information about the zygomatico-buccal plexus (ZBP) in the masseteric and buccal regions. Therefore, this study aimed to help clinicians avoid this ZBP injury by predicting their common location. This study was conducted in forty-two hemifaces of twenty-nine embalmed cadavers by conventional dissection. The characteristics of the buccal branch (BB) and the ZBP were investigated in the mid-face region. The results presented that the BB gave 2-5 branches to emerge from the PG. According to the masseteric and buccal regions, the BB were arranged into ZBP in three patterns including an incomplete loop (11.9%), a single-loop (31.0%), and a multi-loop (57.1%). The mean distance and diameter of the medial line of the ZBP at the corner of the mouth level were 31.6 (6.7) and 1.5 (0.6) mm respectively, while at the alar base level were 22.5 (4.3) and 1.1 (0.6) mm respectively. Moreover, the angular nerve arose from the superior portion of the ZBP at the alar base level. The BB formed a multiloop mostly and showed a constant medial line of ZBP in an area approximately 30 mm lateral to the corner of the mouth, and 20 mm lateral to the alar base. Therefore, it is recommended that physicians should be very careful when performing facial rejuvenation in the mid-face region.

Damage to the Temporal Branch of the Facial Nerve From Mohs Micrographic Surgery

BACKGROUND

The temporal branch of the facial nerve is at risk of damage during Mohs micrographic surgery (MMS). This complication leads to motor deficit in the ipsilateral upper face with resultant functional and cosmetic impairment.

OBJECTIVE

To identify patient, tumor, and surgical risk factors associated with temporal nerve damage.

MATERIALS AND METHODS

A single-institution, retrospective review of MMS cases involving anatomic sites within the temporal nerve danger zone was performed. Risk factors were compared between cases with and without nerve damage.

RESULTS

Of 616 cases within the danger zone, 28 (4.5%) had postoperative nerve dysfunction. Variables significantly associated with dysfunction included patient immunosuppression, tumor size, aggressive tumor histology, recurrent tumors, high degree of subclinical spread, and greater average number of Mohs stages. Preoperative tumor size and postoperative defect size of ≥3 cm resulted in a ×37 and ×40 increased odds of nerve damage, respectively. Sex, age, and basal versus squamous cell carcinoma were not significantly associated with temporal nerve damage. No patients with a postoperative defect size measuring <2 cm had nerve damage.

CONCLUSION

The overall risk of damage to the temporal nerve during MMS is low, but there are certain risk factors that warrant increased counseling about this potential complication.

Application of customized integration titanium mesh in the treatment of complicated zygomatic complex fractures: A prospective randomized clinical study

The present study aimed to quantitatively evaluate the outcomes of the application of customized integration titanium mesh (CITM) in treating unilateral complicated zygomatic complex fractures. A prospective, randomized, controlled clinical study was conducted. Patients were randomly divided into the experimental group who underwent treatment with CITM, and the control group who underwent treatment just with traditional titanium plates. The X² test and student t-test were used for statistical analyses. Twenty patients who required surgery for unilateral complicated zygomatic complex fracture were included in this study. The results showed that the mean of average distance (AD) between pre- and postoperative CT measurements was 0.487 mm in the experimental group and 1.173 mm in the control group (P < 0.001). Compared with the control group, the experimental group had superior zygomatico-facial symmetry (P＜0.05), a shorter average operation time (150 min versus 229 min; P < 0.001), and a higher rate of anatomic reduction (80.0% versus 30.0%; P＜0.05). In conclusion, CITM deserves to be promoted for the treatment of complicated zygomatic complex fractures. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR1800016818).

The Anatomic Landmark Approach to Extratemporal Facial Nerve Repair in Facial Trauma

Objective

In this study, we aimed to examine the topical anatomic landmarks of the facial nerve (facial nerve areas) and their application in cases of extratemporal facial nerve injury in maxillofacial trauma.

Materials and methods

We analyzed 25 maxillofacial trauma patients with facial paralysis who underwent facial nerve reanimation surgery at the Ho Chi Minh City National Hospital of Odonto-Stomatology. The characteristics of each trauma case, including the mechanism of injury, the length of the facial injury, and the location/position of injury, were recorded. The association of the injured nerves with the trauma characteristics and the external landmarks of the facial danger zones was analyzed.

Results

The buccal branches had the highest rate of paralysis (22/25 cases), followed by zygomatic branches (15/25), frontal branches (11/25), marginal branches (6/25), and the main trunk (1/25). There were four areas related to the external facial nerve landmarks (facial nerve areas) that helped us find the affected nerves: wounds in Area 1 resulted in frontal branch paralysis in five out of eight cases (62.5%); wounds in Area 2 resulted in zygomatic branch paralysis in 8/13 cases (61.5%) and buccal branch paralysis in 12/12 cases (100%); wounds in Area 3 resulted in marginal branch paralysis in 5/10 cases (50%); and wounds in Area 4 alone resulted in main trunk paralysis in one out of four cases or at least two main branches in three out of four cases.

Conclusion

Extratemporal facial paralysis after facial trauma can be complex and highly variable, leading to difficulty in finding and repairing facial nerves. Thorough clinical examination and evaluation of trauma characteristics can aid in the identification of facial paralysis and repair. Mapping facial wounds using the four anatomic surface landmarks (Areas 1-4 as outlined in this research) helped us anticipate which branches might be traumatized and estimate the position of the distal and proximal endings to repair the nerves in all cases.

Overexpression of c-Jun inhibits erastin-induced ferroptosis in Schwann cells and promotes repair of facial nerve function

Myelin undergoes various changes after nerve injury, and c‐Jun has a close relationship with Schwann cells (SCs). However, it remains unclear whether c‐Jun can be involved in nerve repair by regulating ferroptosis. To explore this, we first set up a facial nerve injury model and detected the changes of ferroptosis‐related proteins and c‐Jun by immunofluorescence and Western blot. Then, we cultured RSC 96 and pSCs, and studied the potential regulatory relationships by a combination of experimental methods such as CCK‐8, ELISA, immunofluorescence, qRT‐PCR, Western blot and viral transfection. Finally, we corroborated the role of c‐Jun through animal experiments. Our experiments revealed that ferroptosis occurs after facial nerve injury. Erastin decreased GPX4, c‐Jun proteins and GSH content, while PTGS2, NRF2, HO‐1 proteins, MDA, Fe²⁺ and ROS contents increased. This effect was inhibited after c‐Jun overexpression but was reversed after the addition of c‐Jun siRNA. Besides, we proved in vivo that c‐Jun could inhibit ferroptosis and promote the recovery of facial nerve function. In conclusion, our study identified the relationship between c‐Jun and ferroptosis during peripheral nerve injury repair, which provides new ideas for studying peripheral nerve injury and repair.

Controlled release of ciliary neurotrophic factor from bioactive nerve grafts promotes nerve regeneration in rats with facial nerve injuries

It is critical to repair severed facial nerves, as lack of treatment may cause long-term motor and sensory impairments. Ciliary neurotrophic factor (CNTF) plays an important role in terms of enhancing nerve axon regrowth and maturation during peripheral nerve regeneration after injury. However, simple application of CNTF to the transected nerve site does not afford functional recovery, because it is rapidly flushed away by bodily fluids. The aim of the present study was the construction of a new, bioactive composite nerve graft facilitating persistent CNTF delivery to aid the reconstruction of facial nerve defects. The in vitro study showed that the bioactive nerve graft generated sustainable CNTF release for more than 25 days. The bioactive nerve graft was then transplanted into the injury sites of rat facial nerves. At 6 and 12 weeks post-transplantation, functional and histological analyses showed that the bioactive nerve graft featuring immobilized CNTF significantly enhanced nerve regeneration in terms of both axonal outgrowth and Schwann cell proliferation in the rat facial nerve gap model, compared to a collagen tube with adsorbed CNTF that initially released high levels of CNTF. The bioactive nerve graft may serve as novel, controlled bioactive release therapy for facial nerve regeneration.

The efficacy of corticosteroid after facial nerve neurorrhaphy: a systematic review and meta-analysis of randomized controlled trial

OBJECTIVES

The benefit of corticosteroids following facial nerve neurorrhaphy in the setting of complete transection is questionable. This systematic review and meta-analysis aimed to evaluate corticosteroid efficacy on facial nerve regeneration and functional recovery after complete disruption and neurorrhaphy.

METHODS

Randomized controlled trials on both human and animal models from Ovid MEDLINE and Ovid EMBASE studying corticosteroid efficacy in complete facial nerve disruption followed by neurorrhaphy were included. Data were extracted and pooled for meta-analysis. The outcomes were evaluated from electrophysiology, histology, and functional recovery. However, no randomized controlled trial in human was performed. Possibly, performing human trials with histopathology may not be feasible in clinical setting.

RESULTS

Six animal studies (248 participants) met inclusion criteria. Electrophysiologic outcomes revealed no differences in latency (Standardized Mean Difference (SMD) = -1.97, 95% CI -7.38 to 3.44, p = 0.47) and amplitude (SMD = 0.37, 95% CI -0.44 to 1.18, p = 0.37) between systemic corticosteroids and controls. When analysis compared topical corticosteroid and control, the results provided no differences in latency (Mean Difference (MD) = 0.10, 95% CI -0.04 to 0.24, p = 0.16) and amplitude (SMD = 0.01, 95% CI -0.08 to 0.10, p = 0.81). In histologic outcomes, the results showed no differences in axon diameter (MD = 0.13, 95% CI -0.15 to 0.41, p = 0.37) between systemic corticosteroid and control; however, the result in myelin thickness (MD = 0.06, 95% CI 0.04 to 0.08, p < 0.05) favored control group. When comparing systemic corticosteroid with control in eye blinking, the results favored control (MD = 1.33, 95% CI 0.60 to 2.06, p =  0.0004).

CONCLUSIONS

This evidence did not show potential benefits of systemic or topical corticosteroid deliveries after facial nerve neurorrhaphy in complete transection when evaluating electrophysiologic, histologic, and functional recovery outcomes in animal models.

Tetrahedral framework nucleic acids facilitate neurorestoration of facial nerves by activating the NGF/PI3K/AKT pathway

The facial nerve is a crucial nerve in the maxillofacial region and is vulnerable to damage. As a consequence of the complications during nerve restoration, existing remedies have certain limitations, thus the treatment of facial nerve injury is always a perplexing task for people. Regulation of Schwann cells is always the breakpoint of neurorestoration since Schwann cells count a great deal in injured nerve repair. In this study, we presented proof that tetrahedral framework nucleic acids (tFNAs), a kind of nucleic acid nanomaterial, were capable of regulating the neurorestorative pathway NGF/PI3 K/AKT, resulting in the activation of a series of cell behaviors related to injured nerve restoration such as proliferation and migration. In vivo experiments also proved that tFNAs enhanced the expressions of axon and myelin marker proteins, impelled histological recovery, promoted the efficient restoration of nerve conduction and muscle movement. Additionally, tFNAs possessed excellent biocompatibility and superior endocytosis ability. Thus, there is good potential for tFNAs to be applied in the therapy of facial nerve injury or even peripheral nerve injury.

Evaluation of Postoperative Repair Effect of Oral Tumors Based on Free Ultrasound Flap Transplantation

In this paper, the treatment of oral tumors with free flap transplantation based on ultrasound contrast is studied, and the repair effect is analyzed and evaluated in-depth, the postoperative quality of life of patients with oral malignant tumors is evaluated, and the factors affecting their quality of life are analyzed. 120 patients with oral malignant tumors were selected. The continuity of the jaws, neck clearance method, clinical stage, tumor recurrence, radiotherapy, and chemotherapy all have varying degrees of impact on the postoperative quality of life. Multivariate analysis suggests that tumor recurrence has the greatest impact on the quality of life of patients followed by jaw continuity, tumor stage, with or without neck clearance. First, the early detection rate of tumors should be improved, and the tumors should be removed as completely as possible during the operation to avoid residues. If necessary, cervical lymph node dissection can be performed. Patients with discontinuous jaws should be reconstructed and repaired in time to restore the maxillofacial shape and function of the patients, to greatly reduce the impact on the quality of life of patients after surgery.

Facial Nerve Repair: Bioengineering Approaches in Preclinical Models

Injury to the facial nerve can occur after different etiologies and range from simple transection of the branches to varying degrees of segmental loss. Management depends on the extent of injury and options include primary repair for simple transections and using autografts, allografts, or conduits for larger gaps. Tissue engineering plays an important role to create artificial materials that are able to mimic the nerve itself without extra morbidity in the patients. The use of neurotrophic factors or stem cells inside the conduits or around the repair site is being increasingly studied to enhance neural recovery to a greater extent. Preclinical studies remain the hallmark for development of these novel approaches and translation into clinical practice. This review will focus on preclinical models of repair after facial nerve injury to help researchers establish an appropriate model to quantify recovery and analyze functional outcomes. Different bioengineered materials, including conduits and nerve grafts, will be discussed based on the experimental animals that were used and the defects introduced. Future directions to extend the applications of processed nerve allografts, bioengineered conduits, and cues inside the conduits to induce neural recovery after facial nerve injury will be highlighted.

Efficacy of surgical repair for the functional restoration of injured facial nerve

Background

Early surgical repair to restore nerve integrity has become the most commonly practiced method for managing facial nerve injury. However, the evidence for the efficacy of surgical repair for restoring the function of facial nerves remains deficient. This study evaluated the outcomes of surgical repair for facial nerve lesions.

Methods

This retrospective observational study recruited 28 patients with the diagnosis of facial nerve injury who consecutively underwent surgical repairs from September 2012 to May 2019. All related clinical data were retrospectively analyzed according to age, sex, location of the facial nerve lesion, size of the facial nerve defect, method of repair, facial electromyogram, and blink reflex. Facial function was then stratified with the House-Brackmann grading system pre-operation and 3, 9, 15, and 21 months after surgical repair.

Results

The 28 patients enrolled in this study included 17 male and 11 female patients with an average age of 34.3 ± 17.4 years. Three methods were applied for the repair of an injured facial nerve, including great auricular nerve transplantation in 15 patients, sural nerve grafting in 7 patients, and hypoglossal to facial nerve anastomosis in 6 patients. Facial nerve function was significantly improved at 21 months after surgery compared with pre-operative function (P = 0.008). Following surgical repair, a correlation was found between the amplitude of motor unit potential (MUP) and facial nerve function (r = -6.078, P = 0.02). Moreover, the extent of functional restoration of the facial nerve at 21 months after surgery depended on the location of the facial nerve lesion; lesions at either the horizontal or vertical segment showed significant improvement(P = 0.008 and 0.005), while no functional restoration was found for lesions at the labyrinthine segment (P = 0.26).

Conclusions

For surgical repair of facial nerve lesions, the sural nerve, great auricular nerve, and hypoglossal-facial nerve can be grafted effectively to store the function of a facial nerve, and MUP may provide an effective indicator for monitoring the recovery of the injured nerve.

Progress in facial reinnervation

Facial nerve injury often results in facial paralysis, which seriously affects the patients both aesthetically and functionally. Facial nerve reinnervation methods, including direct anastomosis, nerve graft, nerve transposition, cross-facial nerve graft, and combined surgeries, have recently become a hot topic with many new procedures being explored. This study summarizes the relevant literatures and discusses the scope of application, advantages, and disadvantages of the different methods. The treatment options or combined surgeries for facial nerve reinnervation should be individualized for specific patients to achieve the best reanimation outcome with good static symmetry, facial tone, and spontaneous, natural, symmetrical, and strong facial movements.