Misdiagnosis of Facial Nerve Palsy: A Case Report of Sporadic Vestibular Schwannomas (Non-NFM2) Causing Facial Nerve Palsy Be Misled by Bell’s Palsy in a Child

We report a case of a rare sporadic Vestibular Schwannoma of a 9-month-old girl who had a right-sided lower motor type facial nerve palsy. The patient was initially diagnosed with Bell’s palsy and received steroid treatment accordingly, two months later the patient’s condition deteriorated, and further evaluation of CT and MRI brain was conducted that showed a mass lesion in the posterior fossa causing compression on the facial nerve. Misdiagnosis of facial nerve paralysis is common among children due to multiple related etiologies and varying rates of incidence in comparison to adults. The authors hope to address this issue in this report. Background: Facial nerve paralysis has been a matter of concern for many researchers to understand its nature, causes and presentation according to different age groups. In adults, Bell’s palsy (BP), the idiopathic form of facial nerve paralysis, is more common compared to children where most cases are due to secondary etiologies. Therefore, pediatricians are in an important position to identify these patients early in order to launch the most effective diagnostic and treatment approaches.

Evaluation of Vestibular Function in Diagnosis of Vestibular Schwannomas

Vestibular schwannomas(VS)are benign tumors of the vestibular nerve.The common first symptoms are hearing loss and tinnitus,followed by imbalance,vertigo,and facial nerve involvement.The subjective symptoms of VS patients are not consistent with the severity of vestibular lesions and the results of vestibular tests,which often interfere with clinicians’diagnoses.Thus,the main screening and diagnostic methods for VS are audiometry and magnetic resonance imaging(MRI),ignoring the evaluation of vestibular function at the source of pathological lesions.With the development and improvement of vestibular evaluation technology and its wide application in the clinic,modern vestibular examination technology can reflect the severity and frequency of vestibular lesions and compensation from multiple perspectives,providing an objective basis for the diagnosis and treatment of vestibular diseases.In this report,we review the results and characteristics of vestibular tests in VS patients and further clarify the clinical value of vestibular function assessment in the diagnosis and treatment of VS.

Evaluation of pure-tone audiometric protocols in vestibular schwannoma screening

The objective was to evaluate the pure-tone audiogram-based screening protocols in VS diagnostics.We retrospectively analyzed presenting symptoms,pure tone audiometry and MRI finding from 246 VS patients and 442 controls were collected to test screening protocols(AAO-HNS,AMCLASS-A/B,Charing Cross,Cueva,DOH,Nashville,Oxford,Rule3000,Schlauch,Seattle,Sunderland)for sensitivity and specificity.Results were pooled with data from five other studies,and analysis of sensitivity,specificity and positive likelihood ratio(LR+)for each protocol was performed.Our results show that protocols with significantly higher sensitivity(AMCLASS-A/B,Nashville)show also significantly lowest specificity,and tend to have low association(positive likelihood ratio,LR+)to the VS.The highest LR+was found for protocols AAO-HNS,Rule3000 and Seattle.In conclusions,knowing their properties,screening protocols are simple decision-making tools in VS diagnostic.To use the advantage of the highest sensitivity,protocols AMCLASS-A+B or Nashville can be of choice.For more reasonable approach,applying the protocols with high LR+(AAO-HNS,Rule3000,Seattle)may reduce the overall number of MRI scans at expense of only few primarily undiagnosed VS.

Gastrointestinal Symptoms—A Rare Complication of Untreated CPA Tumor

Cerebellopontine angle (CPA) lesions account for up to 10% of all intracranial tumors. Most CPA tumors are benign, but can cause nerve damage or compress the surrounding structures if left untreated. The typical presentation is with adult-onset sensorineural hearing loss or non-pulsatile tinnitus. In some patients, this goes unnoticed, and presentation is delayed until the lesion is much larger and presents with symptoms related to mass effect. We present the case study of 63 years old gentleman, who had suspected left CPA lesion on CT head done few years ago for dizziness and left-sided facial numbness. MRI could not be done at that time due to his MRI incompatible pacemaker leading to delay in his management eventually causing loss of patient to the follow up. He later developed progressive difficulty in walking which was initially attributed to as secondary to vasovagal syncope and postural hypotension. He eventually presented to us with intractable nausea and vomiting, worsening headache and ataxia. He had an urgent CT head which showed significant growth in the lesion with compression of the surrounding structures and obstructive hydrocephalus. He was given steroids which improved his nausea and vomiting, followed by undergoing surgery in regional center leading to significant improvement in his gait within few days of surgery. He unfortunately continued to have a degree of ataxia and facial numbness. This case illustrates a rare presentation of CPA tumor with symptoms of nausea and vomiting as a result of mass effect of the growing tumor. In addition, this review also shows the importance of regularly following up the patients with suspected CPA lesions on initial scans which will help with identifying the increase in size of lesion promptly and potentially preventing advanced complications of CPA tumors. We suggest regular monitoring of these patients to timely manage the lesion and avoid the potential life-threatening complications.

The translabyrinthine approach in residency training.“Step by step”surgical anatomy from the dissection laboratory to the operative room

Surgical anatomy training in a dedicated research laboratory and attendance to focused“hands-on”dissection courses are of high educational importance in order to acquire and maintain surgical expertise in skull base surgery,both for young and more experienced surgeons.Nevertheless,transitioning surgical skills and anatomic knowledge from the laboratory to the operative room it is not free of challenges,especially during skull base approaches where the three-dimensional surgical orientation can be quite complex.We present a“step-by-step”and“side-by-side”surgical anatomy report on a translabyrinthine approach that was practiced in the laboratory then performed in the operative room by the surgical team,and we compare surgical anatomy exposures while discussing intraoperative techniques,nuances and challenges,both in the laboratory and the operative room.

Microsurgery for vestibular schwannoma:analysis of short-term clinical outcome

Background:Total removal of the vestibular schwannoma when preserving the function of the facial nerve is difficult.The objective of the current study was to investigate the short-term clinical outcome of vestibular schwannoma removal via retro-sigmoid approach.Methods:One-hundred consecutive patients diagnosed with vestibular schwannoma were surgically treated between December 2018 and August 2019 in Xuanwu Hospital,Capital Medical University.The clinical classification,surgical position,gross total removal rate,the anatomical and functional preservation rates of facial nerve,and the postoperative complications were retrospectively analyzed.Results:All 100 patients including 34 males and 66 females were operated on via retro-sigmoid approach.According to Koos vestibular schwannoma grading system,18 cases were grade 2,34 cases were grade 3,and 48 cases were grade 4.According to Hannover vestibular schwannoma grading system,5 cases were T2,6 cases were T3a,8 cases were T3b,30 cases were T4a,and 51 cases were T4b.Seventy-three surgeries were performed under lateral position,and 27 cases were operated under semi-sitting position.The gross total removal rate was 90.0%;the anatomic reservation rate of the facial nerve was 96.0%.According to the House-Brackman system,the facial nerve function was grades 1-2 in 78.0%cases,grade 3 in 7.0%cases,and grades 4-5 in 15%cases.For patients with effective hearing before operation,the hearing reservation rate was 19.0%.Two patients(2.0%)developed intracranial hematoma after operation.Conclusion:Most vestibular schwannoma could be completely removed with good postoperative facial nerve function.If total removal of tumor is difficult,we should give priority to the functional preservation of the nerve function.

Original article： Removal of vestibular schwannoma and facial nerve preservation using small suboccipital retrosigmoid craniotomy

Background Vestibular schwannoma, the commonest form of intracranial schwannoma, arises from the Schwann cells investing the vestibular nerve. At present, the surgery for vestibular schwannoma remains one of the most complicated operations demanding for surgical skills in neurosurgery. And the trend of minimal invasion should also be the major influence on the management of patients with vestibular schwannomas. We summarized the microsurgical removal experience in a recent series of vestibular schwannomas and presented the operative technique and cranial nerve preservation in order to improve the rates of total tumor removal and facial nerve preservation. Methods A retrospective analysis was performed in 145 patients over a 7-year period who suffered from vestibular schwannomas that had been microsurgically removed by suboccipital retrosigmoid transmeatus approach with small craniotomy. CT thinner scans revealed the tumor size in the internal auditory meatus and the relationship of the posterior wall of the internal acoustic meatus to the bone labyrinths preoperatively. Brain stem evoked potential was monitored intraoperatively. The posterior wall of the internal acoustic meatus was designedly drilled off. Patient records and operative reports, including data from the^electrophysiological monitoring, follow-up audiometric examinations, and neuroradiological findings were analyzed. Results Total tumor resection was achieved in 140 cases （96.6%） and subtotal resection in 5 cases. The anatomical integrity of the facial nerve was preserved in 91.0% （132/145） of the cases. Intracranial end-to-end anastomosis of the facial nerve was performed in 7 cases. Functional preservation of the facial nerve was achieved in 115 patients （Grade ! and Grade ]I, 79.3%）. No patient died in this series. Preservation of nerves and vessels were as important as tumor removal during the operation. CT thinner scan could show the relationship between the posterior wall of the internal acoustic meatus and bone labyrinths, that is helpful for a safe drilling of the posterior wall of the internal acoustic meatus. Conclusions The goal of every surgery should be the preservation of function of all cranial nerves. Using the retrosigmoid approach with small craniotomy is possible even for large schwannomas. Knowing the microanatomy of the cerebellopontine angle and internal auditory meatus, intraoperating neurophysiological monitoring of the facial nerve function, and the microsurgical techniques of the surgeons are all important factors for improving total tumor removal and preserving facial nerve function.

Isolated cochlear neuritis from varicella reactivation mimicking a vestibular schwannoma

We present a case of a patient with progressive unilateral sensorineural hearing loss and tinnitus with internal auditory canal enhancement on magnetic resonance imaging (MRI) secondary to isolated cochlear neuritis from varicella reactivation. MRI following antiviral treat-ment showed resolution of enhancement. Varicella reactivation is commonly seen in the form of Ramsay Hunt syndrome, which is known to produce abnormal MRI enhancement from facial and vestibulocochlear neuritis;however, its characteristic clinical signs aid the diagnosis. This case is unique in that the only manifestation of varicella infection was unilateral hearing loss. This case outlines the importance of maintaining a broad differential diagnosis in the evaluation of unilateral hearing loss as well as recognizing the limited specificity of MRI.

Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma

Background::Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope.The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma(VS),as an alternative to a binocular surgical microscope.Methods::Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018.The demographics and tumor characteristics(size,Koos grade,composition[cystic or solid mass])were matched between the two groups of patients.The following outcome measurements were compared between the two groups:duration of surgery,volume of blood loss,extent of tumor resection,number of operating field adjustments,pre-and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery,complications and surgeons’comfortability.Results::A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope(cases,n=39)or a surgical microscope(control,n=42).Patients in the two groups had comparable tumor location(P=0.439),Koos grading(P=0.867),and composition(P=0.891).While no significant differences in the duration of surgery(P=0.172),extent of tumor resection(P=0.858),facial function(P=0.838),and hearing ability(P=1.000),patients operated on under an exoscope had less blood loss(P=0.036)and a fewer field adjustments(P<0.001).Both primary and assistant surgeons reported a high level of comfort operating under the exoscope(P=0.001 and P<0.001,respectively).Conclusions::The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs,as compared to a surgical microscope.After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax,the exoscope system provided a comfortable,high-resolution visualization without compromising operational efficiency and patient safety.

Summary and consensus in 7th International Conference on acoustic neuroma:An update for the management of sporadic acoustic neuromas

Sporadic vestibular schwannoma (acoustic neuroma) is a benign tumor arising from cochleovestibular nerve. Nowadays, various specialties and medical centers are treating this dis-ease, and the multidisciplinary collaboration is the trend. In an effort to promote a uniform stan-dard for reporting clinical results, even for treatment indications, the mainly controversies were posed and discussed during the 7th International Conference on acoustic neuroma, and the agreement was summarized by the Committee of this conference. The main symptoms grading and tumor stage should note its name of classification for making them comparable. The goal of the modern managements for vestibular schwannoma is to improve the quality of life with lower mortality, lower morbidity and better neurological function preservation. The experience of surgical team and their preference might be a major factor for the outcome. Because of lack-ing of long-term follow-up large data after radiotherapy, and with the development of microsur-gery, radiotherapy is now less recommended except for recurrent cases or elderly patients.