Facial Monitoring Research Articles

Intraoperative monitoring and early recognition of facial nerve root in vestibular schwannoma surgery.

The removal of vestibular schwannomas carries a risk of facial palsy. This study aims to evaluate the usefulness and technical aspects of intraoperative monitoring (IOM) for the facial nerve. A total of 96 patients who underwent surgery for vestibular schwannoma were retrospectively investigated. The cohort was divided into two groups: those with intraoperative facial nerve monitoring (IOM group) and those without IOM (non-IOM group). Preoperative and postoperative facial nerve functions were assessed using the House-Brackmann (HB) scale immediately after surgery, at discharge, and at the 1-year follow-up. HB grade I and II were classified as satisfactory outcomes, HB grade III and IV as intermediate, and HB grade V and VI as poor. Facial nerve functions were compared between the groups. Additionally, the ratio of satisfactory results was investigated in the IOM group, focusing on whether the root exit zone (REZ) was identified at an early or late stage of surgery. Among the 65 (67%) patients in the IOM group and 31 (32%) patients in the non-IOM group, there were no differences in demographic and tumor characteristics. The extent of resection varied from subtotal to gross total removal, with no statistical differences between the groups. Although facial nerve function was more favorably preserved in the non-IOM group immediately after surgery, this trend reversed at discharge and the 1-year follow-up, showing significant statistical differences. In the IOM group, more patients achieved satisfactory outcomes when the REZ was identified early compared to late during tumor resection. Intraoperative facial nerve monitoring provides more satisfactory outcomes in preserving nerve function in vestibular schwannoma surgery. Early recognition of the REZ may contribute to improved surgical outcomes.

Intraoperative Facial Nerve Monitoring during Parotidectomy: The Current Practices and Patterns of the Korean Society of Head and Neck Surgery (KSHNS).

Objectives: This study aimed to evaluate the current practices and trends of intraoperative facial nerve (FN) monitoring (IOFNM) during parotidectomy. Methods: A questionnaire containing 33 questions collecting information on the usage, indications, settings, techniques, loss of signal (LOS) management, anesthesiologist cooperation, and perception of usefulness of IOFNM was distributed among 348 members of the Korean Society of Head and Neck Surgery (KSHNS) via a dedicated website. Results: The response rate was approximately 25.6%, and 97% of the respondents reported using IOFNM selectively or routinely during parotidectomy. IOFNM usage decreased as the surgeon's level of experience increased (p = 0.089), from 100% in those with less than 5 years of experience to 75% in those with 20 or more years. Approximately 95% of respondents reported that the initial event threshold for electromyography activity used was 50-149 μV. Moreover, 52.4% of respondents performed neural mapping of the FN before visual identification. Initial management of LOS in visually intact FNs included checking the IOFNM system (75.3%), confirmation of muscle relaxant dosage (75.3%), and facial twitch identification (58.8%). Further management included proceeding with surgery regardless of persistent LOS (81.2%) and steroid administration sometimes or all of the time (72.9%). Overall, 98.8% of respondents found IOFNM beneficial for safe execution of parotidectomy. Conclusions: The majority of KSHNS surgeons used IOFNM during parotidectomy, although the clinical implementation of the procedure and LOS management varied between practitioners. This could be attributed to the lack of standardized protocols for IOFNM, emphasizing the need for the development of evidence-based consensus guidelines for all institutions.

Outcomes of a modified technique of partial parotidectomy and novel parotid tumour position classification from a single surgeon prospective database.

Conservative parotidectomy for benign tumours reduces facial nerve palsy, without increasing local recurrence. We report a modified technique of partial parotidectomy and using a novel description of tumour position, explore relationships between tumour position and histological margins, facial nerve palsy and local recurrence. A prospectively collected single surgeon parotidectomy database was analysed, including tumour location (superficial/deep lobe; central/peripheral) and outcomes. A partial parotidectomy identified the facial nerve and the proximal portion of its branches with a macroscopically clear resection margin. Mean follow up was 5.9 years for pleomorphic adenomas. Three hundred and three patients underwent parotidectomy; 257 (84.8%) were superficial and 46 (15.2%) deep lobe. Tumour position was recorded in 291: 236 (81.1%) were peripheral tumours and 55 (18.9%) central. Histological margin involvement was similar in central and peripheral tumours, both overall and for superficial and deep lobe tumours, but was commoner in central deep lobe tumours, (P = 0.003). Temporary partial facial nerve palsy occurred in 21 (6.9%), with one permanent partial nerve palsy (0.3%). Deep lobe tumours and total parotidectomy were associated with facial nerve palsy (P = 0.01). Facial nerve monitoring reduced the risk of palsy (P < 0.01). Local recurrence of pleomorphic adenomas was uncommon, occurring in 3 (2.0%) of 151 patients. This series confirms the safety and adequacy of more conservative partial parotidectomy for benign tumours, highlighting most tumours are peripheral, but not more prone to histological margin involvement or local recurrence, and with routine intraoperative facial nerve monitoring, is achieved with low facial nerve palsy rates.

Minimum intraoperative testing battery for cochlear implantation: the international practice trend.

In cochlear implantation (CI) surgery, there are a wide variety of intraoperative tests available. However, no clear guide exists on which tests must be performed as the minimum intraoperative testing battery. Toward this end, we studied the usage patterns, recommendations, and attitudes of practitioners toward intraoperative testing. This study is a multicentric international survey of tertiary referral CI centers. A survey was developed and administered to a group of CI practitioners (n = 34) including otologists, audiologists and biomedical engineers. Thirty six participants were invited to participate in this study based on a their scientific outputs to the literature on the intraoperative testing in CI field and based on their high load of CI surgeries. Thirty four, from 15 countries have accepted the invitation to participate. The participants were asked to indicate the usage trends, perceived value, influence on decision making and duration of each intraoperative test. They were also asked to indicate which tests they believe should be included in a minimum test battery for routine cases. Thirty-two (94%) experts provided responses. The most frequently recommended tests for a minimum battery were facial nerve monitoring, electrode impedance measurements, and measurements of electrically evoked compound action potentials (ECAPs). The perceived value and influence on surgical decision-making also varied, with high-resolution CT being rated the highest on both measures. Facial nerve monitoring, electrode impedance measurements, and ECAP measurements are currently the core tests of the intraoperative test battery for CI surgery.

Facial Nerve Injury after Extracapsular Dissection for Benign Parotid Tumors with and without Intraoperative Monitoring: A Retrospective Study of a Single Center.

Facial nerve injury (FNI) is the most common complication of parotid surgery and manifests as FN paralysis. The use of intraoperative facial nerve monitoring (IFNM) is becoming an established intraoperative aid for surgeons, assisting in the identification of the location and dissection of the facial nerve trunk or branches. The postoperative outcomes of parotid surgery with and without monitoring have been addressed in only a limited number of studies. The objective of this study is to evaluate the incidence of postoperative paralysis in patients undergoing extracapsular dissection (ED) for benign parotid tumors concerning the use or non-use of IFNM. The retrospective study was conducted at the Maxillo-Facial Department of the Magna Graecia University of Catanzaro. The patients were divided into two groups: Group 1 consisted of patients who underwent surgery without IFNM (1 January 2015 to 31 December 2018); Group 2, on the other hand, consisted of patients who underwent surgery with IFNM (1 January 2019 to 31 December 2022). Group 2 employed the Nerve Integrity Monitor (Medtronic's NIM®). To classify the FN function, we employed the modified House-Brackmann classification system. To evaluate the dependence between the "use of IFNM" and "postoperative paralysis", a descriptive analysis was conducted, including applying the Chi-squared test and calculating the Pearson correlation. Subsequently, a binary logistic regression model was applied to further evaluate the correlation between the latter. The level of statistical significance was set at p < 0.05. A total of 276 patients were included in the study: 120 subjects were assigned to Group 1 (43.5%, comprising 60 men and 60 women) and 156 subjects were assigned to Group 2 (56.5%, comprising 93 men and 63 women). In 91.7% of the cases (n. 253, precisely 105 in Group 1 and 148 in Group 2), no FNI occurred. In 8.33% of the cases (n. 23, specifically 15 in Group 1 and 8 in Group 2), postoperative paralysis was observed. Of these subjects, only two in Group 1 had permanent paralysis (8.69%); therefore, 91.31% had transient paralysis. As a result, 91.31% of the subjects exhibited transient paralysis. In the case of FNI, 78% of the cases involved the marginal mandibular branch (n. 18), 13% involved the temporo-zygomatic branch (n. 3), and 7% involved more than one branch (n = 2). The results of the multivariable binary logistic regression analysis demonstrated that the use of IFNM was a statistically significant influencing factor, with an estimated reduction in postoperative paralysis of approximately 62% (OR 0.378; 95% CI: 0.155-0.92). In Group 2, the occurrence of transient complications was significantly reduced (OR 0.387; 95% CI: 0.149-1.002 with p < 0.05). The use of IFNM in the ED for benign parotid tumors significantly reduces the rate of FNI and, consequently, postoperative FN paralysis. On the other hand, the use of monitoring systems must not replace the experience and anatomical knowledge of the surgeon.

Surgical and anesthetic considerations in a unique case of temporary iatrogenic facial nerve paralysis after superficial parotidectomy

Parotid neoplasms are a common indication for parotidectomy, a procedure that carries a risk of facial paralysis. Modern advances in surgical and anesthesia techniques, including facial nerve monitoring have resulted in low rates of permanent facial nerve paralysis. We present a case of temporary postoperative right facial nerve paralysis after intact facial nerve neuromonitoring at the completion of resection. The proposed mechanism of this phenomenon is related to the effects of local anesthetic infiltration from a fat graft used for oncologic reconstruction. This case emphasizes the importance of judicious and carefully timed local anesthetic use, clear facial nerve monitoring, and coordination between care teams.

Comprehensive Mapping and Dynamic Monitoring of the Temporal Branch of the Facial Nerve in Complex Cranial Reconstruction Surgery and Revision Cranioplasty.

Facial nerve (FN) injury is a significant risk during complex cranial reconstruction surgeries, especially in revision cases where normal anatomy is distorted. The authors introduce a technique to mitigate FN injury, including preoperative FN mapping, intraoperative FN mapping, and continuous FN monitoring. Preoperative mapping uses a handheld ball-tip stimulator to elicit compound muscle action potentials (CMAP) in the frontalis muscle. Needle electrodes are placed above the orbital margin to record responses, starting at the stylomastoid foramen and extending until the entire temporal branch is mapped. Intraoperatively, continuous mapping is achieved using an electrified insulated suction device, allowing dynamic mapping during soft tissue dissection. Continuous monitoring involves placing stimulation electrodes near the stylomastoid foramen and recording CMAP responses from the frontalis and orbicularis oculi/orbicularis oris muscles. The authors tested this technique in 5 patients. The authors successfully mapped the temporal branch of the FN with isolated frontalis CMAP recordings in all patients. Intraoperative FN mapping and continuous monitoring were successfully performed in all cases. Two patients experienced complete cessation of FN CMAPs, which resumed upon loosening the tension on the myocutaneous flap held by fishhooks. One patient showed a 39% decrement in frontalis CMAP that did not recover. Despite these issues, all patients had intact FN function postoperatively and at follow-up. Our technique shows promise in mitigating FN injury during complex cranial reconstruction and cranioplasty revision surgery. Further research with a larger cohort is needed to confirm efficacy and statistical significance.

LATEST ADVANCES IN FACIAL NERVE INTRAOPERATIVE MONITORING FOR VESTIBULAR SCHWANNOMA - UP TO DATE 2024

Introduction: Vestibular schwannoma, a benign tumor of the eighth cranial nerve, can be treated with radiosurgery, microsurgery, or observation. This study aims to present advances in intraoperative monitoring techniques for preserving facial nerve function during acoustic neuroma surgeries. By sharing the latest evidence, we hope to influence clinical practices for the benefit of patients. Methodology: Thus, we conducted a comprehensive literature review using the Scopus database, we searched for articles published from 2018 to 2023 using the keywords "facial paralysis," "acoustic neuroma," and "intraoperative monitoring." Results: The use of electromyographic parameters in the pre, intra, and post-resection monitoring of vestibular schwannoma provides valuable indicators of both the functional state of the facial nerve and the tumor adherence. This information plays a crucial role in making safe decisions regarding the extent of tumor resection while minimizing the risk of facial nerve damage during surgery. Supramaximal stimulation of the facial nerve in proximity to the tumor is of utmost importance to preserve facial function. However, the presence of a separate intermediate nerve poses challenges in accurately detecting false positives. Therefore, monitoring the facial nerve during surgery becomes essential to prevent potential injuries and to predict both short- and long-term outcomes. Conclusion: Intraoperative electrophysiological facial nerve monitoring is a crucial strategy to reduce postoperative facial paralysis. While the best technique is still under debate, several options exist to enhance monitoring efficacy and patient safety. By staying informed, clinicians can make better decisions to improve patient outcomes.

Real-time surgical simulation training for recurrent laryngeal nerve and facial nerve dissection

BackgroundHead and neck surgical simulation training (SST) is an important part in otolaryngology head and neck surgical education. In this study, we provide a live porcine model for SST in recurrent laryngeal nerve (RLN) and facial nerve (FN) dissection for otolaryngology head and neck residents. MethodsA lecture with surgical manual is provided to illustrate the surgical landmarks of pig, and step-by-step procedures for thyroid and parotid surgery, as well as neck dissection. We used 4-month-old pig weighting 32 kg for the SST. The mentor demonstrated result of RLN injury with continuous nerve monitoring. Participants used monopolar stimulation probe (4 pulse/s, 100 μs, 3-8 mA; Medtronic) to identify and intermittent monitor the RLN and FN during the SST. After the dissection course, we conducted a questionnaire survey to check the effectiveness of this training model. ResultsTotal 30 participants were recruited, including 16 female and 14 male resident doctors. There were 1, 4 and 25 learners for 3rd year, 4th and 5th years residents, respectively. Before this training course, 53 % (16/30) and 63 % (19/30) had successful experience in finding the RLN and FN, respectively. After the SST, all of our participants had successful identify the RLN and FN (p-value <0.01); all had positive response to stimulation and familiar with the procedure. ConclusionsThe live porcine model is effectiveness in SST for RLN and FN dissection. Live porcine model with real-time RLN and FN monitoring should be provided for otolaryngology head and neck resident training.

Utility and Prognostic Value of Intraoperative Blink Reflex in Trigeminal or Facial Nerve Monitoring in Skull Base Surgeries: A Systematic Review

Blink reflex (BR) is an oligosynaptic reflex that involves the ophthalmic branch of the trigeminal nerve (TN), ipsilateral main sensory and trigeminospinal nuclei, bilateral facial nuclei, and the facial nerves (FNs). Theoretically, as BR tests the function of both TN and FNs simultaneously, it is an ideal tool for monitoring the status of TN and FNs during skull base surgeries. Nevertheless, it has been used only recently in surgeries as the use of anesthesia limits its use. For this systematic review, 2 authors input the search terms [(Blink Reflex) AND (Intraoperative Neuromonitoring OR Neuro Intraoperative Monitoring OR Intraoperative OR NIOM OR IONM) AND (skull base surgery OR Facial Nerve OR Trigeminal Nerve OR Microvascular Decompression OR Hemifacial Spasm)] in MEDLINE through its PubMed interface and other search engines. Articles that fulfilled the inclusion and exclusion criteria were obtained and scrutinized. Seven observational articles with a total of 437 participants were included. All 5 studies that described the use of BR in FN surgery noted that intraoperative BR is beneficial, safe, sensitive, specific, and predictive of outcomes, while 2 articles describing patients with trigeminal neuralgia recommended use of BR in microvascular decompression of TN. Intraoperative BR is a sensitive, specific, and safe monitoring technique that has good predictability of facial paresis and paresthesia among patients undergoing MVD for trigeminal neuralgia and primary hemifacial spasm and patients undergoing cerebellopontine angle tumor resection.

Cochlear implantation through retro-facial approach with congenital microtia malformation with facial nerve deformity: a case report

The difficulty of cochlear implantation in patients with congenital microtia is usually increased due to the vague anatomical marks and facial nerve malformation. The common types of facial nerve malformation include facial nerve bony cover loss, aberrant position, and bifurcation malformation. Bifurcation malformation may obscure the oval window, press against stapes, and bifurcate in the vestibular window while obscuring the round window. It is important to correctly identify the facial nerve and choose a reasonable surgical approach to avoid postoperative complications. This article describes a case of profound sensorineural hearing loss due to facial nerve malformation in our institution. The patient underwent cochlear implantation through the retro-facial approach. There was no facial nerve injury or dysfunction symptoms such as facial paralysis and hemifacial spasm 2 years after the operation, and the cochlear implant works well. The score of the categories of the auditory performance（CAP） questionnaire was 7, and the score of the speech intelligibility rating（SIR） questionnaire was 4. When the round window cannot be exposed through the facial recess approach during surgery, the retro-facial approach is a feasible method. To avoid facial nerve injury, a thin-section CT of the temporal bone should be performed before the middle and inner ear surgery for patients with facial nerve malformation, and the intraoperative facial nerve monitor should be used to clarify the course of the facial nerve to avoid injury.

Retracted: Facial Nerve Monitoring under Different Levels of Neuromuscular Blockade with Cisatracurium Besilate in Parotid Tumour Surgery.

[This retracts the article DOI: 10.1155/2021/5655061.].

Impact of Surgeon's Experience and Tumor's Nature in the Use of Intraoperative Facial Nerve Monitoring in Superficial Parotidectomy. Preliminary Results from a Single-Center Retrospective Analysis.

To assess the effectiveness of intraoperative facial nerve monitoring (IFNM) compared to non-monitoring in the prevention of post-operative facial nerve palsy during superficial parotidectomy. Patients treated with curative intent for parotid gland tumors between January 2020 and January 2022 were included. The study population has been divided in 2 groups, based on IFNM: the group A included patients operated with IFNM, whilst group B was the non-monitoring group. A further classification focused on the pathologies and the surgeons' experience. The study group included 58 patients, 27 female and 31 male. The mean age was 45.7yr (range 36-78). No statistical difference has been found in post-operative HB grade between group A and B. The analysis of patients affected by pleomorphic surface lobe adenomas of the parotid did not show a statistical difference in HB outcome (p > 0.05). The analysis of the effect of surgeons' experience in IFNM advantage did not show statistical difference for superficial parotid tumors. The results of the present study suggest that the use of IFNM during parotid surgery is not mandatory to preserve the VII nerve function, both in case of primary tumor and in case of recurrence, and even when surgery is performed by less experienced surgeon compared to those cases treated by a more experienced surgeon.

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.

Expert consensus on intraoperative facial nerve monitoring

Expert consensus on intraoperative facial nerve monitoring

Operative techniques and materials in ossiculoplasty

Successful ossiculoplasty aims to improve conductive hearing loss by restoring the mechanical transmission of energy from the tympanic membrane to the oval window. Ossiculoplasty is typically performed under general anesthesia with facial nerve monitoring as standard practice in our institution. Titanium implants have become the mainstay choice of prosthesis, due to its low density, high durability, and lower extrusion rate compared to other alloplastic implants. While microscopic techniques for ossiculoplasty have been the traditional approach, endoscopic ossiculoplasty has risen in popularity due to improved visualization of the middle ear.

Iatrogenic Facial Nerve Injury in Head and Neck Surgery in the Presence of Intraoperative Facial Nerve Monitoring With Electromyography: A Systematic Review

Iatrogenic Facial Nerve Injury in Head and Neck Surgery in the Presence of Intraoperative Facial Nerve Monitoring With Electromyography: A Systematic Review

Intraoperative Monitoring of the Facial Nerve during Microvascular Decompression for Hemifacial Spasm.

This review article discusses the clinical significance of intraoperative neurophysiological monitoring (IONM), provides recommendations for monitoring protocols, and considers the interpretation of results in microvascular decompression (MVD) for hemifacial spasm (HFS). The lateral spread response (LSR) is an important monitoring parameter during MVD. It helps to identify the responsible blood vessel and confirms its thorough decompression from the facial nerve. The disappearance of the LSR during surgery is associated with favorable clinical outcomes. Standard and revised monitoring protocols and the confirmation of LSR persistence and disappearance are also discussed. The blink reflex and other facial nerve monitoring modalities, such as free-running electromyography, facial motor evoked potentials, F-waves, and the Z-L response, are further considered.

The Outcomes of Superficial Parotidectomy with Intraoperative Facial Nerve Monitoring: Experience in Sawanpracharak Hospital 2020 to 2022

Objective: To determine the outcomes of patients undergone parotidectomy with or without facial nerve monitoring. Materials and Methods: The present study was a retrospective study that included 35 patients underwent superficial parotidectomy with pathologic findings of benign parotid tumor. The patients were divided into two groups. Intraoperative facial nerve monitoring was performed in 15 patients and did not monitor in 20 patients. Data were compared between the surgical groups with intraoperative facial nerve monitoring and the groups without intraoperative facial nerve monitoring using the chi-square test and independent t-test. Results: Patients who underwent parotidectomy between January 1, 2020 and December 31, 2022, whose pathologic findings were benign, a total of 35 cases were divided into 15 patients underwent surgery with intraoperative facial nerve monitoring and 20 patients underwent surgery without intraoperative facial nerve monitoring. There was no statistical difference in operation time and saliva leakage. However, there was a statistical difference in intraoperative blood loss, postoperative facial nerve weakness rate, and postoperative earlobe numbness. Conclusion: The most common complication of parotidectomy is paralysis of the facial nerve. The present study showed that intraoperative facial nerve monitoring can reduce facial nerve paralysis, blood loss during surgery and postoperative earlobe numbness. Keywords: Intraoperative facial nerve monitoring; Parotidectomy; Parotid tumor

Intraoperative Neuromonitoring in Vestibular Schwannoma Surgery

Vestibular schwannoma surgery necessitates intraoperative neuromonitoring to secure long-term tumor control by sufficient tumor removal and preservation of neural function. Therein, facial nerve function can be assessed in real-time and quantitatively by intraoperative continuous facial nerve monitoring with repetitive direct stimulation. The ABR and, further, CNAP, are closely monitored for the continuous assessment of the hearing function. In addition, the evoked masseter and extraocular electromyograms, SEP, MEP, and neuromonitoring of the lower cranial nerves are implemented as needed. In this article, we introduce our neuromonitoring techniques during vestibular schwannoma surgery with an illustrative video.