Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function

Intraoperative Protection of Pharyngeal Autonomic Nerves: Preventing Dysphagia After Anterior Cervical Decompression and Fusion Surgery

OBJECTIVE

The study aims to investigate whether intraoperative protection of the pharyngeal autonomic nerve can effectively reduce the incidence of postoperative dysphagia following anterior cervical decompression and fusion surgery (ACDF).

METHODS

A retrospective analysis was conducted on 130 cases that underwent ACDF from January 2018 to June 2022 at our hospital. Divided into nonautonomic neuroprotection (NANP) group and autonomic neuroprotection group based on whether receive protective measures for the pharyngeal autonomic nerve during surgery. General data were recorded and compared between the 2 groups. Postoperative outcomes were evaluated using Neck Disability Index, Japanese Orthopaedics Association (JOA) score, and JOA improvement rate. The incidence and severity of postoperative dysphagia were assessed using Bazaz dysphagia assessment criteria and swallowing-quality of life questionnaire.

RESULTS

There were no significant differences in general data (P > 0.05). The average operation time and intraoperative blood loss also showed no significant differences (P > 0.05). Both groups showed significant improvements in Neck Disability Index and JOA scores at all follow-up time points compared to preoperative scores (P < 0.01). The incidence of postoperative dysphagia in the autonomic neuroprotection group was significantly lower than that in the NANP group at all follow-up time points (P < 0.05). Both group showed a significant reduction in scores 3 days postoperatively compared to preoperative scores (P < 0.01), and the NANP group also showed significant reductions in scores at 3 month and 1 year postoperative follow-up time points compared to preoperative scores (P < 0.01).

CONCLUSIONS

The adoption of pharyngeal autonomic nerve protective measures during ACDF can effectively lower the probability of postoperative dysphagia.

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review

BACKGROUND AND OBJECTIVES

Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse.

METHODS

A single-institution cohort study and systematic literature review of LCNS were performed.

RESULTS

Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients.

CONCLUSION

Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control-particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

Advancing Intraoperative Neurophysiological Monitoring With Human Reflexes

Human reflexes are simple motor responses that are automatically elicited by various sensory inputs. These reflexes can provide valuable insights into the functioning of the nervous system, particularly the brainstem and spinal cord. Reflexes involving the brainstem, such as the blink reflex, laryngeal adductor reflex, trigeminal hypoglossal reflex, and masseter H reflex, offer immediate information about the cranial-nerve functionality and the overall state of the brainstem. Similarly, spinal reflexes such as the H reflex of the soleus muscle, posterior root muscle reflexes, and sacral reflexes provide crucial information about the functionality of the spinal cord and peripheral nerves. One of the critical benefits of reflex monitoring is that it can provide continuous feedback without disrupting the surgical process due to no movement being induced in the surgical field. These reflexes can be monitored in real time during surgical procedures to assess the integrity of the nervous system and detect potential neurological damage. It is particularly noteworthy that the reflexes provide motor and sensory information on the functional integrity of nerve fibers and nuclei. This article describes the current techniques used for monitoring various human reflexes and their clinical significance in surgery. We also address important methodological considerations and their impact on surgical safety and patient outcomes. Utilizing these methodologies has the potential to advance or even revolutionize the field of intraoperative continuous monitoring, ultimately leading to improved surgical outcomes and enhanced patient care.

The transcervical-transparotid corridor for management of parapharyngeal space neoplasms: strengths and limits in a bi-institutional retrospective series

BACKGROUND AND PURPOSE

Parapharyngeal space (PPS) neoplasms represent 1% of all head and neck tumors and are mostly benign. Surgery is the mainstay of treatment and the transcervical-transparotid (TC-TP) corridor still represents the workhorse for adequate PPS exposure. Our series investigates strengths and limits of this approach on a multi-institutional basis.

METHODS

We reviewed consecutive patients submitted to PPS surgery via TC-TP route between 2010 and 2020. Hospital stay, early and long-term complications, and disease status were assessed.

RESULTS

One hundred and twenty nine patients were enrolled. Most tumors were benign (79.8%) and involved the prestyloid space (83.7%); the median largest diameter was 4.0 cm. The TC-TP corridor was used in 70.5% of patients, while a pure TC route in about a quarter of cases. Early postoperative VII CN palsy was evident in 32.3% of patients, while X CN deficit in 9.4%. The long-term morbidity rate was 34.1%, with persistent CN impairment detectable in 26.4% of patients: carotid space location, lesion diameter and malignant histology were the main independent predictors of morbidity. A recurrence occurred in 12 patients (9.4%).

CONCLUSIONS

The TC-TP corridor represents the benchmark for surgical management of most of PPS neoplasms, though substantial morbidity can still be expected.

Functional outcome following intracapsular resection of head and neck peripheral nerve sheath tumors: a retrospective cohort

BACKGROUND

Intracapsular resection of head and neck peripheral nerve sheath tumors (PNST) has emerged as a nerve-preserving technique compared to en bloc resection. The aim of this study was to evaluate and compare the functional outcome of both surgical techniques performed at a single tertiary referral center.

METHODS

This is a retrospective cohort of patients with head and neck PNST undergoing surgical resection from 2011 to 2021 at the Tel Aviv Sourasky Medical Center. Demographic data, the nerve of origin and surgical technique, including the use of intraoperative nerve monitoring were recorded and analyzed in association with postoperative functional outcomes.

RESULTS

Overall, 25 patients who had a cervical or parapharyngeal PNST resected were included. Nerve function was preserved in 11 of 18 patients (61%) who underwent intracapsular resection, while all those who underwent en bloc resections inevitably suffered from neurologic deficits (100%, N = 7). Sympathetic chain origin and an apparent neurologic deficit pre-operatively were associated with postoperative neural compromise.

CONCLUSION

Improved functional outcome can be anticipated following intracapsular resection of extracranial head and neck PNST compared to complete resection, particularly in asymptomatic patients.

Quantification of vessel separation using the carotid-jugular angle to predict the nerve origin of neck peripheral nerve sheath tumours: a pooled analysis of cases from the literature and a single-center cohort

BACKGROUND

Postoperative nerve palsy is a major complication following resection of neck peripheral nerve sheath tumours (PNSTs). Accurate preoperative identification of the nerve origin (NO) can improve surgical outcomes and patient counselling.

MATERIAL AND METHODS

This study was a retrospective cohort and quantitative analysis of the literature. The authors introduced a parameter, the carotid-jugular angle (CJA), to differentiate the NO. A literature review of neck PNST cases from 2010 to 2022 was conducted. The CJA was measured from eligible imaging data, and quantitative analysis was performed to evaluate the ability of the CJA to predict the NO. External validation was performed using a single-centre cohort from 2008 to 2021.

RESULTS

In total, 17 patients from our single-centre cohort and 88 patients from the literature were analyzed. Among them, 53, 45, and 7 patients had sympathetic, vagus, and cervical nerve PNSTs, respectively. Vagus nerve tumours had the largest CJA, followed by sympathetic tumours, whereas cervical nerve tumours had the smallest CJA ( P <0.001). Multivariate logistic regression identified a larger CJA as a predictor of vagus NO ( P <0.001), and receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.907 (0.831-0.951) for the CJA to predict vagus NO ( P <0.001). External validation showed an AUC of 0.928 (0.727-0.988) ( P <0.001). Compared with the AUC of the previously proposed qualitative method (AUC=0.764, 0.673-0.839), that of the CJA was greater ( P =0.011). The cut-off value identified to predict vagus NO was greater than or equal to 100°. Receiver operating characteristic analysis showed an AUC of 0.909 (0.837-0.956) for the CJA to predict cervical NO ( P <0.001), with a cut-off value less than 38.5°.

CONCLUSIONS

A CJA greater than or equal to 100° predicted a vagus NO and a CJA less than 100° predicted a non-vagus NO. Moreover, a CJA less than 38.5 was associated with an increased likelihood of cervical NO.

Triggered episodic vestibular syndrome and transient loss of consciousness due to a retrostyloidal vagal schwannoma: a case report

Background

Various conditions may trigger episodic vertigo or dizziness, with positional changes being the most frequently identified condition. In this study, we describe a rare case of triggered episodic vestibular syndrome (EVS) accompanied by transient loss of consciousness (TLOC) linked to retrostyloidal vagal schwannoma.

Case description

A 27-year woman with known vestibular migraine presented with a 19-month history of nausea, dysphagia, and odynophagia triggered by swallowing food and followed by recurrent TLOC. These symptoms occurred independently of her body position, resulting in a weight loss of 10 kg within 1 year and in an inability to work. An extensive cardiologic diagnostic work-up undertaken before she presented to the neurologic department was normal. On the fiberoptic endoscopic evaluation of swallowing, she showed a decreased sensitivity, a slight bulging of the right lateral pharyngeal wall, and a pathological pharyngeal squeeze maneuver without any further functional deficits. Quantitative vestibular testing revealed an intact peripheral-vestibular function, and electroencephalography was read as normal. On the brain MRI, a 16 x 15 x 12 mm lesion in the right retrostyloidal space suspicious of a vagal schwannoma was detected. Radiosurgery was preferred over surgical resection, as resection of tumors in the retrostyloid space bears the risk of intraoperative complications and may result in significant morbidity. A single radiosurgical procedure (stereotactic CyberKnife radiosurgery, 1 x 13Gy) accompanied by oral steroids was performed. On follow-up, a cessation of (pre)syncopes was noted 6 months after treatment. Only residual infrequent episodes of mild nausea were triggered by swallowing solid food remained. Brain MRI after 6 months demonstrated no progression of the lesion. In contrast, migraine headaches associated with dizziness remained frequent.

Discussion

Distinguishing triggered and spontaneous EVS is important, and identifying specific triggers by structured history-taking is essential. Episodes being elicited by swallowing solid foods and accompanied by (near) TLOC should initiate a thorough search for vagal schwannoma, as symptoms are often disabling, and targeted treatment is available. In the case presented here, cessation of (pre)syncopes and significant reduction of nausea triggered by swallowing was noted with a 6-month delay, illustrating the advantages (no surgical complications) and disadvantages (delayed treatment response) of first-line radiotherapy in vagal schwannoma treatment.

A Rare Case of Cervical Vagal Nerve Schwannoma in a 30-Year-Old Ethiopian Man

Schwannoma is a slowly growing benign tumor that arises from Schwann cells. Schwannomas affect both genders equally. It occurs in any age group, but most cases are seen between the third and fifth decade. About one-fourth to one-third of extracranial schwannomas cases originate in the head and neck region. The vagus nerve, followed by the cervical sympathetic chain, is the leading site of origin in the neck region. The majority of patients with schwannomas are asymptomatic. Patients with vagal nerve schwannomas in the neck primarily present with hoarseness of voice due to paralysis of the vocal cords. Because of their rarity and the lack of a neurologic deficit as a presenting symptom, preoperative consideration of schwannomas is tough, and several differential diagnoses may be entertained.The mainstay of treatment for vagal nerve schwannoma is complete surgical excision. Here we present a rare case of cervical vagal nerve schwannoma in a 30-year-old male farmer from Ethiopia. The patient presented with a gradually increasing neck swelling of 10 years duration. He started to have hoarseness in his voice five months prior to his presentation. On examination, he had a huge anterior neck swelling. He had two FNAC results, which were inconclusive, and a neck CT. With the consideration of multinodular goiter versus spindle cell neoplasm, the neck was explored, and complete excision of the mass was done. The excisional biopsy turned out to be a classical cervical schwannoma. So this report aims to make physicians aware of the rare case of schwannomas, particularly vagal nerve schwannomas. Clinicians should consider schwannomas in the differential diagnosis of a patient presenting with a cervical mass. Furthermore, they need to be well aware of the diagnostic workup, mainly the imaging modalities, which are essential for proper preoperative planning, surgical treatment, and postoperative complications of cervical schwannomas.

Evaluation of Carotid Space Schwannoma Using Ultrasonography: Characteristics and Role in Defining the Nerve of Origin

OBJECTIVES

We aimed to evaluate the ultrasonography (US) characteristics of carotid space schwannoma and their role in identifying the nerve of origin.

METHODS

This prospective study enrolled patients with cervical carotid space schwannoma accessible by US. The US characteristics of vagus nerve schwannomas (VNSs) and sympathetic nerve schwannomas (SNSs) were assessed; a carotid space schwannoma was defined as a VNS if the tumor originated in the mid-vagal region and an SNS if it arose posterior to the intact vagus nerve, displacing the vagus nerve anteriorly.

RESULTS

Twenty patients with carotid space schwannoma were enrolled. The vagus and sympathetic nerves were identified as the nerve of origin in 12 and 8 patients, respectively. VNSs were centered at levels II, III, and IV in 5, 3, and 4 patients, respectively, while SNSs were centered at levels II (7 patients) and IV (1 patient) (P = .105). The maximal diameters were 3.2 and 4.8 cm for VNSs and SNSs, respectively (P = .011). Internal vascularity was absent and low in 9 and 3 VNSs, respectively, and low and intermediate in 4 SNSs each (P = .002). Twelve patients with VNSs underwent active surveillance without immediate surgery; no adverse events occurred during the 55.2-month follow-up period. Eight patients with potential SNSs underwent surgery, confirming the sympathetic nerve as the nerve of origin.

CONCLUSIONS

US facilitates identification of the nerve of origin in cervical carotid space schwannoma. VNSs are more frequent in infrahyoid locations and tend to be smaller in size with lower vascularity compared with SNSs on US.

A Rare Case of Cervical Vagus Nerve Schwannoma in an Adult Patient

Schwannomas of the head and neck are relatively rare benign tumors that derive from the Schwann cells. Schwannomas are usually asymptomatic; however, tumors of bigger size may produce unspecific symptoms due to compression of the adjacent anatomic structures. Vagus nerve schwannomas may present as solitary neck masses, produce hoarseness of voice, or induce paroxysmal cough on palpation, which is also pathognomonic. Preoperative diagnosis is challenging and imaging studies may play a vital role in the diagnosis. Surgical treatment with complete tumor removal is the treatment of choice. In this study, we present a case of vagus nerve schwannoma in an adult male patient.

Pre-operative embolization and excision of vagal schwannoma with rich vascular supply: A case report and literature review

RATIONALE

Schwannomas are benign tumors wrapped in the nerve sheath and can originate from the myelin sheath of the cranial nerve. In previous literature reports, most of the tumors were solid tumors, which can be removed only by surgery. This case report describes a unique case of vagal schwannoma, which, unlike previous cases, involves a dominant arterial supply, and discusses the pre-operative evaluation, relevant radiographic findings, and surgical process of the case in detail.

PATIENT CONCERNS

A 31-year-old woman sought treatment for pain in the left side of the neck when turning her head. A mass on the left side of the neck was found on enhanced computed tomography with a maximum diameter of 6.8 cm, along with multiple tortuous, thickened vascular shadows, and pressure on the left pharyngeal cavity.

DIAGNOSIS

The pathological results showed schwannoma.

INTERVENTIONS

Considering the unusual size of the tumor and thickened blood vessels revealed by pre-operative computed tomography, general anesthesia and biopsy were conducted first to confirm the diagnosis. Excessive bleeding occurred during the process; thus, the tumor was only partially removed before the wound closed after hemostasis. Digital subtraction angiography indicated that the tumor was supplied by multiple arteries, and the tumor was removed by pre-operative embolization plus intra-operative removal.

OUTCOMES

Combined with embolization and surgical resection, the tumor was completely removed, the nerve was partially preserved, and the patient had postoperative hoarseness.

LESSON

The present case indicates the possibility of vascularly supplied vagal schwannoma; thus, it is necessary to conduct pre-operative digital subtraction angiography.

OUP accepted manuscript

Schwannoma arising from vagal nerve is a rare tumour. It is a slow-growing, benign mass, but rarely it might undergo malignant transformation. We report a case of a 55-year-old woman with asymptomatic Xth cranial nerve schwannoma in the left side of the neck. Initially, during the ultrasound examination, the tumour was misconceived to be a malignant lymph node. The patient underwent complete surgical excision of it. Histopathological examination revealed typical features of schwannoma. Clinical diagnose of cervical vagal nerve schwannoma is difficult. Magnetic resonance imaging is as an accurate diagnostic tool for these tumours. Surgical excision is the treatment of choice.

Massive vagal schwannoma in an 11-year-old girl

We describe an unusual case of a young girl presenting with a large vagal schwannoma necessitating a transcervical-mandibulotomy approach for total tumor resection. The presentation is unique due to the size of the lesion, the patient's age, the operative approach, and molecular pathology.

Recent Developments of Intraoperative Neuromonitoring in Thyroidectomy

At present, intraoperative neuromonitorization (IONM) with surface electrode-based endotracheal tube (ETT) is a standard method in thyroidectomy and can be performed either intermittently IONM (I-IONM) or continuously IONM (C-IONM). Despite the valuable contribution of I-IONM to the thyroidectomy, it still has limitations regarding the recording electrodes and stimulation probe. New approaches for overcoming the limitations of I-IONM and developing the method are taking attention. Most of the technical issues of IONM with surface electrode-based ETT are related with inadequate contact of electrodes to the vocal cords. Nowadays, efficiency of various recording electrodes is under investigation. Recording electrodes such as needle electrodes applied to thyroarytenoid or posterior cricoarytenoid muscle (PCA), surface electrodes applied to the PCA, and needle or adhesive electrodes applied to the tracheal cartilage or skin, can make safe recordings similar to the ETT electrodes. Despite their invasiveness, needle electrodes record higher electromyography (EMG) amplitudes than tube electrodes do. Adhesive surface electrodes make safe EMG recordings, although amplitudes of these electrodes are usually lower than those of the tube electrodes. These different types of electrodes are less affected by tracheal manipulations and amplitude changes are lower compared to the tube electrodes.

During C-IONM, an additional stimulation probe is applied to the vagus nerve after dissecting the nerve circumferentially. Recently, without applying a probe, a new continuous monitorization method called laryngeal adductor reflex CIONM (LAR-CIONM) using sensorial, central, and motor components of LAR arch which is an automatic, primitive brainstem reflex protecting the tracheoesophageal tree from foreign body aspiration, has been implemented. Afferent track of LAR communicates laryngeal mucosa to the brainstem by internal branch of the superior laryngeal nerve and efferent track reaches larynx through recurrent laryngeal nerve. Total outcome of LAR activation is the closure of laryngeal entry by bilateral vocal cord adduction. In LAR-CIONM, a stimulus is given by an electrode from one side of surface electrode-based ETT and amplitude response of the LAR at the vocal cord is followed on the operation side. Recently, it has been reported that real-time EMG response can be obtained with stimulation probe cables applied to dissectors or energy devices during the dissection through I-IONM.

Recurrent laryngeal nerve schwannoma: same setting of resection and injection laryngoplasty

A 33-year-old woman was diagnosed with right recurrent laryngeal nerve (RLN) schwannoma. She presented with a long history of hoarseness, and only recently developed dysphagia. On physical examination, a mass was observed over the right cervical level IV. Endoscopic examination of the larynx showed that she had right unilateral vocal cord palsy. She successfully underwent transcervical resection of the tumour followed by injection laryngoplasty. This study discusses the presentation of the tumour, radiological findings, our working diagnosis and treatment options of RLN schwannoma.

Schwannoma of the sympathetic trunk: A case report

Introduction and Importance

Schwannomas are benign tumors commonly found in the cranial vault at the cerebellopontine angle. Schwannomas could arise from any nerve that has Schwann sheath. Their most common extra-cranial localization is the parapharyngeal space. Schwannomas do not usually metastasize, and recurrence is uncommon.

Case presentation

We present a case of a sympathetic trunk schwannoma in a patient that presented with dysphagia and a painful neck mass. Oro-pharyngeal examination revealed the presence of a mass filling-up the left tonsillar fossa, and pushing the uvula to the right side. The larynx was also deviated to the right due to the mass effect. The mass was resected en-bloc with the involved part of the sympathetic trunk. The patient developed Horner's syndrome postoperatively.

Clinical discussion

The occurrence of Sympathetic trunk Schwannomas is very rare. The majority of patients presented with a cervical mass and non-specific symptoms. The most effective treatment is surgical resection. Our experience suggests sympathetic trunk Schwannomas as a differential diagnosis of slow-growing neck masses and asserts that the surgical resection is the main treatment.

Conclusion

The occurrence of Schwannomas in the sympathetic trunk is rare. High clinical suspicion is required to achieve the preoperative diagnosis. The optimal management is the total surgical resection. Recurrence is uncommon when the mass is totally resected.

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Schwannoma of the sympathetic trunk is a probable diagnosis for slow-growing cervical masses.

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Totally surgical resection is the chosen procedure to avoid recurrence.

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Nerve grafts are not recommended to reconstruct the damaged part of the nerve.

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Microsurgery techniques could prevent developing Horner's Syndrome after mass resecting.

Resecting a solitary cervical vagal nerve neurofibroma via endoscopic surgery: a case report

Neurofibromas predominately consist of Schwann cells and fibroblasts, which mainly originate from neurofibromatosis type 1. However, solitary cervical vagal nerve neurofibroma (VNN) has rarely been reported in previously published literature. Additionally, the onset of VNN is characteristically chronic, asymptomatic, and insidious, and is often discovered unexpectedly through physical examination or imaging. The exact etiology and pathogenesis of VNN are yet to be clarified and need further exploration. Consequently, the definitive diagnosis of VNN mainly depends on pathological and immunohistochemical examinations. Immunohistochemically, tumor cells are positive for transcription factor S-100, SRY-related HMG-box (SOX)-10, and vascular marker CD34 will contribute to the diagnosis of VNN. In this uncommon case of left cervical VNN, the patient received comprehensive radiological evaluation before the operation and then underwent mass resection through endoscopic surgery via an axillary and chest wall approach. The patient was satisfied with the postoperative appearance of the neck. Besides, no postoperative complications or recurrence were observed during the consecutive six-month follow-up. Therefore, the successful application of total endoscopic surgery via the bilateral axilla-breast approach (BABA) on this case of neurogenic tumor presents new insights into expanding the operative indications of this technique, which could be a rational candidate for this kind of neck tumor with the requirements of satisfactory aesthetic appearance.

Head and Neck Cancer Treatments from Chemotherapy to Magnetic Systems: Perspectives and Challenges

BACKGROUND

Cancer is one of the diseases causing society's fears as a stigma of death and pain. Head and Neck Squamous Cell Carcinoma (HNSCC) is a group of malignant neoplasms of different locations in this region of the human body. It is one of the leading causes of morbidity and mortality in Brazil, because these malignant neoplasias, in most cases, are diagnosed in late phases. Surgical excision, chemotherapy and radiotherapy encompass the forefront of antineoplastic therapy; however, the numerous side effects associated with these therapeutic modalities are well known. Some treatments present enough potential to help or replace conventional treatments, such as Magnetic Hyperthermia and Photodynamic Therapy. Such approaches require the development of new materials at the nanoscale, able to carry out the loading of their active components while presenting characteristics of biocompatibility mandatory for biomedical applications.

OBJECTIVE

This work aims to make a bibliographical review of HNSCC treatments. Recent techniques proven effective in other types of cancer were highlighted and raised discussion and reflections on current methods and possibilities of enhancing the treatment of HNSCC.

METHOD

The study was based on a bibliometric research between the years 2008 and 2019 using the following keywords: Cancer, Head and Neck Cancer, Chemotherapy, Radiotherapy, Photodynamic Therapy, and Hyperthermia.

RESULTS

A total of 5.151.725 articles were found, 3.712.670 about cancer, 175.470 on Head and Neck Cancer, 398.736 on Radiotherapy, 760.497 on Chemotherapy, 53.830 on Hyperthermia, and 50.522 on Photodynamic Therapy.

CONCLUSION

The analysis shows that there is still much room for expanding research, especially for alternative therapies since most of the studies still focus on conventional treatments and on the quest to overcome their side effects. The scientific community needs to keep looking for more effective therapies generating fewer side effects for the patient. Currently, the so-called alternative therapies are being used in combination with the conventional ones, but the association of these new therapies shows great potential, in other types of cancer, to improve the treatment efficacy.

Trends in the Management of Non-Vestibular Skull Base and Intracranial Schwannomas

The aim of this review is to analyze the latest trends in the management of non-vestibular skull base and intracranial schwannomas in order to optimize tumor control and quality of life. Non-vestibular cranial nerve schwannomas are rare lesions, representing 5–10% of cranial nerve schwannomas. Management decisions should be individualized depending on tumor size, location and associated functional deficits. Generally, large sized schwannomas exerting significant mass effect with increased intracranial pressure are treated surgically. In some cases, even after optimal skull base resection, it is not possible to achieve a gross total resection because tumor location and extent and/or to reduce morbidity. Thus, subtotal resection followed by stereotactic radiosurgery or fractioned radiotherapy offers an alternative approach. In certain cases, stereotactic radiosurgery or radiotherapy alone achieves good tumor control rates and less morbidity to gross total resection. Finally, given the slow growth rate of most of these tumors, observation with periodic radiographic follow-up approach is also a reasonable alternative for small tumors with few, if any, symptoms.

Continuous neuromonitoring during radiofrequency ablation of benign thyroid nodules provides objective evidence of laryngeal nerve safety

INTRODUCTION

The recurrent laryngeal nerves(RLN) run immediately posterior to the thyroid capsule and could be injured during thyroid radiofrequency ablation(RFA). This study assesses whether RLN functional integrity is altered during RFA using continuous intraoperative neuromonitoring(CIONM).

METHODS

Prospective case series of twenty nodules treated with RFA under general anesthesia utilizing the laryngeal adductor reflex(LAR) for CIONM.

RESULTS

Thirteen nodules abutted the posterior thyroid capsule and 'danger triangle' for RLN injury. The ablative field did not breach the posterior capsule; 40 W was the maximal power used adjacent to the capsule. No patient experienced significant LAR amplitude alterations. Pre and postoperative laryngoscopy and voice assessments were comparable. At 12 months' median follow-up, no patient displayed posterior nodule regrowth.

CONCLUSIONS

This prospective case series supports the premise that benign nodule RFA is safe with regards to RLN functional integrity provided the posterior capsule is not breached by the ablation zone and posterior power is ≤ 40 W.

Valuableness of introduction of laryngeal abductor reflex intraoperative neuromonitoring technique in lower brainstem lesion

Background:

Our aim is to evaluate the use of laryngeal adductor reflex (LAR) for posterior fossa and brainstem surgeries in conjunction with current intraoperative neuromonitoring (IONM) techniques.

Case Description:

The patient is a 62-year-old woman who complained of decreased hearing on her left side, dizziness, and left facial palsy. After proper investigation, she was found to have a left vestibular schwannoma. She was scheduled for the left retrosigmoid approach and electrodes embedded on the surface of the endotracheal tube were inserted to monitor for LAR. Preoperative baseline monitoring was recorded. During intraoperative resection of tumor, a significant bilateral amplitude response decrease of the LAR was noted, along with left side decrease in vocal muscle motor evoked potential amplitude responses and bradycardia. Following the LAR event, owed to numerous other IONM changes, surgery was terminated to avoid any complications.

Conclusion:

LAR is an integral tool to constantly monitor vagus nerve function that can be used in combination with other IONM modalities during lower brainstem and posterior fossa surgeries. We advocate the IONM use of LAR in brainstem surgeries.

Tumor, host and surgery related factors predisposing to cranial nerve deficits after surgical treatment of parapharyngeal space tumors

Propose

Identification of relevant features acquired on preoperative evaluation of parapharyngeal space (PPS) tumors or related to the performed surgical approach that are predictive of the most important complication of surgical treatment of these tumors, cranial nerve palsy.

Methods

This was a retrospective analysis of 68 patients with PPS tumors treated with surgical resection in a tertiary referral center from 2009 to 2019. The preoperative clinical symptoms, age, sex, tumor size, location, histopathological type, surgical approach, radical resection, intraoperative bleeding and the occurrence of complications were collected, evaluated and compared.

Results

Cross-table and chi-square test results revealed that cranial nerve deficits were more common in neurogenic tumors than in other types, including malignant tumors (χ² = 6.118, p = 0.013); the cervical approach was selected more often for neurogenic tumors (χ² = 14.134, p < 0.001); neurogenic tumors were more frequently removed intracapsularly (χ² = 6.424, p = 0.011); and neurogenic tumors were more likely to be located in the poststyloid area (χ² = 17.464, p < 0.001). The two-sample t test revealed a significant correlation between age and the prevalence of cranial nerve complications (t = 2.242, p = 0.031). The mean age in the group of patients with cranial nerve palsy was 45.89 years, and that of the group without complications was 54.69 years. The results of logistic regression confirmed that the risk of nerve deficits was almost 8 times higher for neurogenic tumors (OR = 7.778, p = 0.01). None of the other analyzed variables related to tumor or surgery was significantly correlated with an increased risk of cranial nerve dysfunction.

Conclusion

Surgical resection of tumors other than neurogenic tumors of the PPS reveals no significant risk for permanent neural dysfunction. Tumor size also had no significant effect on the risk of postoperative nerve palsy.

Continuous Laryngeal Adductor Reflex Versus Intermittent Nerve Monitoring in Neck Endocrine Surgery

OBJECTIVE

Intraoperative neuromonitoring (IONM) techniques aim to identify and potentially prevent nerve injury during surgeries. Prior studies into the efficacy of recurrent laryngeal nerve (RLN) IONM convey mixed results, with some claiming equivalence between IONM and no monitoring at all. The goal of the current study was to compare continuous RLN monitoring using the laryngeal adductor reflex (LAR) to intermittent RLN monitoring (intermittent IONM) to determine whether continuous monitoring reduces the incidence of intraoperative RLN injury during neck endocrine surgeries.

METHODS

In this observational, historical case-control study, a historical cohort of patients monitored with intermittent-IONM (group 1, n = 130) were compared to prospectively collected data from consecutive nerves-at-risk monitored continuously with the LAR (LAR-CIONM, group 2, n = 205), at a single center by a single surgeon. The test benefit ratio and relative risk reduction (RRR) for LAR-CIONM over intermittent IONM were calculated.

RESULTS

For group 1, nine nerves at risk exhibited intraoperative LOS with transient postoperative vocal fold (VF) hypomobility (n = 2) or immobility (VFI, n = 7). For group 2, two nerves at risk (0.98%) had sudden intraoperative LAR LOS following bipolar cautery, resulting in postoperative transient VFI (P = .004). In each group, there was one case of permanent postoperative VFI. The test benefit rate ratio for LAR-CIONM demonstrated a dramatic effect at 5.23, with an RRR of 81.0%.

CONCLUSION

LAR-CIONM significantly decreased rates of postoperative transient VF paralysis and paresis over intermittent IONM alone (P = .004). Surgeons should be aware of the benefits and limitations of intermittent IONM versus CIONM. Intermittent IONM, although useful in nerve mapping and intraoperative decision making, has minimal benefit for the prevention of nerve injury, whereas CIONM can potentially reduce nerve injury rates and improve patient outcomes.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:230-236, 2021.