Anatomy of the facial nerve at the condylar area: measurement study and clinical implications

Extracranial Facial Nerve Schwannoma-Histological Surprise or Therapeutic Planning?

Schwannomas (neurilemomas) are benign, slow-growing, encapsulated, white, yellow, or pink tumors originating in Schwann cells in the sheaths of cranial nerves or myelinated peripheral nerves. Facial nerve schwannomas (FNS) can form anywhere along the course of the nerve, from the pontocerebellar angle to the terminal branches of the facial nerve. In this article, we propose a review of the specialized literature regarding the diagnostic and therapeutic management of schwannomas of the extracranial segment of the facial nerve, also presenting our experience in this type of rare neurogenic tumor. The clinical exam reveals pretragial swelling or retromandibular swelling, the extrinsic compression of the lateral oropharyngeal wall like a parapharyngeal tumor. The function of the facial nerve is generally preserved due to the eccentric growth of the tumor pushing on the nerve fibers, and the incidence of peripheral facial paralysis in FNSs is described in 20-27% of cases. Magnetic Resonance Imaging (MRI) examination is the gold standard and describes a mass with iso signal to muscle on T1 and hyper signal to muscle on T2 and a characteristic "darts sign." The most practical differential diagnoses are pleomorphic adenoma of the parotid gland and glossopharyngeal schwannoma. The surgical approach to FNSs requires an experienced surgeon, and radical ablation by extracapsular dissection with preservation of the facial nerve is the gold standard for the cure. The patient's informed consent is important regarding the diagnosis of schwannoma and the possibility of facial nerve resection with reconstruction. Frozen section intraoperative examination is necessary to rule out malignancy or when sectioning of the facial nerve fibers is necessary. Alternative therapeutic strategies are imaging monitoring or stereotactic radiosurgery. The main factors which are considered during the management are the extension of the tumor, the presence or not of facial palsy, the experience of the surgeon, and the patient's options.

Delivering transcutaneous auricular neurostimulation (tAN) to improve symptoms associated with opioid withdrawal: results from a prospective clinical trial

Background

As pharmacological treatments are the primary option for opioid use disorder, neuromodulation has recently demonstrated efficacy in managing opioid withdrawal syndrome (OWS). This study investigated the safety and effectiveness of transcutaneous auricular neurostimulation (tAN) for managing OWS.

Methods

This prospective inpatient trial included a 30-minute randomized, sham-controlled, double-blind period followed by a 5-day open-label period. Adults with physical dependence on opioids were randomized to receive active or sham tAN following abrupt opioid discontinuation. The Clinical Opiate Withdrawal Scale (COWS) was used to determine withdrawal level, and participants were required to have a baseline COWS score ≥ 13 before enrollment. The double-blind period of the study occurred during the first 30-minutes to assess the acute effects of tAN therapy compared to a sham control. Group 1 received active tAN during both the 30-minute double-blind period and the 5-day open-label period. Group 2 received passive sham tAN (no stimulation) during the double-blind period, followed by active tAN during the 5-day open-label period. The primary outcome was change in COWS from baseline to 60-minutes of active tAN (pooled across groups, accounting for 30-minute delay). Secondary outcomes included difference in change in COWS scores between groups after 30-minutes of active or sham tAN, change in COWS scores after 120-minutes of active tAN, and change in COWS scores on Days 2–5. Non-opioid comfort medications were administered during the trial.

Results

Across all thirty-one participants, the mean (SD) COWS scores relative to baseline were reduced by 7.0 (4.7) points after 60-minutes of active tAN across both groups (p < 0.0001; Cohen’s d = 2.0), demonstrating a significant and clinically meaningful reduction of 45.9%. After 30-minutes of active tAN (Group 1) or sham tAN (Group 2), the active tAN group demonstrated a significantly greater COWS score reduction than the sham tAN group (41.7% vs. 24.1%; p = 0.036). Participants across both groups achieved an average COWS reduction up to 74.7% on Days 2–5.

Conclusion

Results demonstrate tAN is a safe and effective non-opioid approach for reducing symptoms of OWS. This study supported an FDA clearance.

Clinical trial registration

clinicaltrials.gov/ct2/show/NCT04075214, Identifier: NCT04075214, Release Date: August 28, 2019.

Facial nerve: A review of the anatomical, surgical landmarks and its iatrogenic injuries

Facial nerve iatrogenic injuries are serious and can negatively affect the quality of life of the patients. Due to the properties of the nerve, the complications are devastating involving the aesthetic appearance and the function of the face. Moreover, the multiple branches of the nerve increase the risk of an iatrogenic injury making the detailed knowledge of the anatomical correlations around them critical. In this review, a meticulous analysis was performed including the surgical procedures posing the greater risk of an iatrogenic injury as well as the full description of all the reported anatomical landmarks involving the extracranial course of the facial nerve.

The Pretragal Superficial Musculoaponeurotic System Fascia: A New Graft Material for Transcanal Tympanoplasty

OBJECTIVE

To compare outcomes of transcanal endoscopic tympanoplasty reconstructed using pretragal superficial musculoaponeurotic system (SMAS) fascia versus temporalis fascia.

STUDY DESIGN

Retrospective patient review and posttreatment questionnaire survey.

SETTING

Tertiary referral center.

PATIENTS

Sixty adult patients with chronic dry tympanic membrane perforation.

INTERVENTIONS

Patients underwent transcanal endoscopic type I tympanoplasty reconstructed using the SMAS fascia between September 2017 and May 2018; outcomes were compared with a matched cohort of patients where the temporalis fascia was used.

MAIN OUTCOME MEASURES

Tympanic membrane closure rate, audiogram threshold, duration of procedure, and donor site scar satisfaction survey.

RESULTS

Sixty patients were included in this study and were evenly divided into the SMAS and temporalis fascia groups. These cohorts were matched for age, sex, side of lesion, perforation size, and preoperative hearing level. The closure rate was 96.7% (29/30) and 93.3% (28/30) (p = 1.0), mean hearing gain was 8.3 ± 6.4 dB versus 8.2 ± 7.1 dB for air-conduction (p = 0.970) and 7.6 ± 5.1 dB versus 8.2 ± 6.8 dB for air-bone gap (p = 0.716), and mean surgical duration was 137.3 ± 23.0 versus 132.2 ± 27.3 minutes (p = 0.432) for the SMAS and temporalis fascia groups, respectively; there were no statistically significant differences for all the parameters listed. The posttreatment questionnaire survey revealed significantly higher acceptance of the SMAS fascia method.

CONCLUSION

This preliminary outcome report of SMAS fascia grafting in transcanal endoscopic type I tympanoplasty showed equivalent surgical outcomes and better cosmetic satisfaction compared with the temporalis fascia. The SMAS fascia is a reasonable alternative to conventional techniques for transcanal tympanoplasty.

The Influence of Dissection Range of the Facial Nerve on Transient Postoperative Facial Palsy in Mandibular Condyle Fractures

PURPOSE

This study examined the relation between dissection range of facial nerve branches and transient postoperative facial palsy caused by nerve traction for open treatment of mandibular condyle fractures using a preauricular approach.

MATERIALS AND METHODS

This retrospective study included 58 patients who underwent rigid fixation of condylar head and upper neck fractures. Patients were divided into 3 groups based on dissection range of the frontal and zygomatic branches. For group 1 (n = 22), the dissection range was extended anteriorly and posteriorly from the condylar borders through the retroparotid approach. The transparotid approach was used in groups 2 (n = 19) and 3 (n = 17) in which nerve dissection was limited to the condylar borders and was extended only anteriorly, respectively. Using multivariate correlation and multiple regression analyses, differences in duration of nerve traction and angle difference by traction from the natural course of the nerve were analyzed according to dissection range, and the recovery period for facial palsy was evaluated.

RESULTS

The duration of nerve traction for group 2 was 77.53 minutes, which was longer than that for groups 1 (66.00 minutes) and 3 (65.41 minutes). The angle differences by traction were 62.42° and 58.00° for the frontal and zygomatic branches in group 2, respectively, which were considerably greater than those in groups 1 (23.32° and 20.14°) and 3 (37.24° and 28.88°). In consequence, group 2 showed the longest recovery, requiring 64.47 days for the frontal branch and 51.63 days for the zygomatic branch. The angle difference by traction had a greater influence on the recovery period than duration of nerve traction.

CONCLUSIONS

Duration of nerve traction and angle difference by traction were quantitatively dependent on the dissection range of facial nerve branches and were related to the recovery period for transient facial palsy.

Relationship between facial nerve damage and transbuccal trocar placement: an anatomical cohort study

The surgical treatment of ramus and mandibular angle fractures is typically performed by intraoral and transbuccal approaches. As these approaches may result in nerve damage, this anatomical study was performed to establish the relationship between the transbuccal trocar position and the likelihood of inducing facial nerve damage. Twenty dissections of the parotid regions were performed after a simulation of surgical approaches aimed at addressing mandibular condylar and angle fractures. Two trocar tubes, ramic and angular, were inserted and left in position throughout the dissection. This procedure allowed the qualitative relationship between the various tube positions and facial nerve damage to be analyzed. The potential risk of contact between the ramic trocar and the facial nerve branches was 90%, while the angular trocar was in contact in 45% of cases. There was no contact with the trunk, cervicofacial division, or temporofacial division of the facial nerve. The contacts occurred at the level of secondary division branches, particularly pronounced for superior and inferior buccal branches, despite the absence of macroscopically visible trauma. Based on these findings, it is proposed that trocars should be used in procedures aimed at addressing subcondylar or angle fractures of the mandible.

Neurovascular structures of the mandibular angle and condyle: a comprehensive anatomical review

BACKGROUND

Various surgical interventions including esthetic surgery, salivary gland excision, and open reduction of fracture have been performed in the area around the mandibular angle and condyle. This study aimed to comprehensively review the anatomy of the neurovascular structures on the angle and condyle with recent anatomic and clinical research.

METHODS AND RESULTS

We provide detailed information about the branching and distributing patterns of the neurovascular structures at the mandibular angle and condyle, with reported data of measurements and proportions from previous anatomical and clinical research. Our report should serve to help practitioners gain a better understanding of the area in order or reduce potential complications during local procedures. Reckless manipulation during mandibular angle reduction could mutilate arterial branches, not only from the facial artery, but also from the external carotid artery. The transverse facial artery and superficial temporal artery could be damaged during approach and incision in the condylar area. The marginal mandibular branch of the facial nerve can be easily damaged during submandibular gland excision or facial rejuvenation treatment. The main trunk of the facial nerve and its upper and lower distinct divisions have been damaged during parotidectomy, rhytidectomy, and open reductions of condylar fractures.

CONCLUSION

By revisiting the information in the present study, surgeons will be able to more accurately prevent procedure-related complications, such as iatrogenic vascular accidents on the mandibular angle and condyle, complete and partial facial palsy, gustatory sweating (Frey syndrome), and traumatic neuroma after parotidectomy.