[To the origins of surgery for acoustic neuromas]

Acoustic neuroma is one of the most common tumors of the posterior cranial fossa. Its removal is always a challenge for the neurosurgeon and the patient. The history of surgery for acoustic neuromas is inextricably linked with the history of neurosurgery in general. The modern surgical community must know history and be able to use it. Only then will the development of surgery lead to the preservation of the quality of life of patients. In the history of surgery for acoustic neuromas, the stages of its development are clearly visible from the description of the clinical picture through the study of the anatomy of the cerebellopontine angle to modern microsurgical removal.

[Early results of intraoperative neurophysiological monitoring in surgical treatment of hemifacial spasm]

BACKGROUND

Neurophysiological monitoring in surgery for hemifacial spasm has been used since the 1990s, when Moller et al. demonstrated the effectiveness of intraoperative assessment of lateral spread response (LSR) regarding postoperative outcomes. Currently, there are conflicting data on effectiveness and feasibility of this technique. Widespread hemifacial spasm determines the relevance of neurophysiological monitoring in surgical treatment of these patients.

OBJECTIVE

To evaluate the effectiveness of various methods of intraoperative neurophysiological monitoring in surgical treatment of hemifacial spasm regarding early postoperative outcomes.

MATERIAL AND METHODS

The study group included 43 patients (8 men and 35 women) aged 26-68 years. We assessed severity of hemifacial spasm using the SMC Grading Scale. All patients underwent vascular decompression of the facial nerve under neurophysiological control: monitoring of transcranial motor evoked potentials from facial muscles (m. orbicularis oculi, m. orbicularis oris, m. mentalis) and recording unilateral LSR. The control group included 23 patients (4 men and 19 women) aged 29-83 years. In this group, facial nerve decompression was performed without neurophysiological control. The effect of neurophysiological monitoring on postoperative outcomes (in-hospital period and 3 postoperative months) after vascular decompression of the facial nerve was assessed using the SMC Grading Scale. We considered severity and incidence of spasms.

RESULTS

Thirty-one (72%) patients in the main group had no spasms of mimic muscles at discharge. In the control group, there were no spasms in 15 patients (65%). At the same time, there were fewer Grade I patients in the control group (12%) compared to the main group (26%). Moreover, 27 (66%) and 12 (52%) patients were free from episodes of hemifacial spasm in both groups, respectively. Patients with hemifacial spasm grade I-II comprised 29% in the main group and 34% in the control group. The number of relapses within three months increased in the control group (13%).

CONCLUSION

Intraoperative monitoring of transcranial motor evoked potentials from the facial muscles and LSR during vascular decompression of the facial nerve increases the efficiency of surgery for hemifacial spasm in early postoperative period. Less number of relapses and lower intensity of hemifacial spasm necessitate neurophysiological monitoring in neurosurgical treatment of these patients.

[Status epilepticus after brain tumor surgery]

ABTRACT

BACKGROUND

Status epilepticus (SE) is characterized by continuous course of clinical and/or electrographic epileptic seizures. There are little data on the course and outcomes of SE after resection of brain tumors.

OBJECTIVE

To analyze clinical and electrographic manifestations of SE, its course and outcomes in short-term period after resection of brain tumors.

MATERIAL AND METHODS

We analyzed medical records of 18 patients over 18 years old between 2012 and 2019. All patients underwent resection of brain tumor and developed SE after surgery. Clinical criteria were repeated epileptic seizures without interictal recovery of consciousness, stereotypical motor phenomena, impaired consciousness with continued epileptic activity according to video-EEG data. We analyzed EEG data, neurological status, CT and laboratory data.

RESULTS

Metastases (33%) and meningiomas (16%) prevailed. Supratentorial tumors were observed in 61% of patients. Two patients had preoperative seizures. Non-convulsive SE was diagnosed in 62% of patients. SE was successfully treated in 77% of cases. Mortality rate in patients with SE was 44%.

CONCLUSION

Early postoperative SE is rare after brain tumor surgery (about 0.09%). Nevertheless, this complication is associated with high mortality. Non-convulsive SE is common (62%) that should be considered in postoperative management.

[Higher efficacy of botulinum toxin therapy for hemifacial spasm recurrence after vascular decompression. Case report and literature review]

Hemifacial spasm (HFS) is an involuntary synchronous tonic and/or clonic contraction of mimic muscles following ipsilateral facial nerve dysfunction. The last one is a result of neurovascular conflict between the facial nerve and vessel. Currently, vascular decompression is a pathogenetic treatment modality for primary HFS. Various authors describe postoperative recurrence of HFS, and botulinum toxin therapy remains the only option for these patients. We aimed to describe the efficacy of botulinum toxin therapy in patients with HFS recurrence after surgical vascular decompression. The article presents a female patient with a long-term history of HFS and botulinum toxin therapy (with different formulations). Efficacy of therapy gradually decreased (progressive reduction of intervals between injections). MRI revealed a close relationship between posterior inferior cerebellar artery and roots of acoustic-facial nerves near the brainstem. The patient underwent vascular decompression of the left facial nerve root under intraoperative monitoring with positive postoperative outcome. However, HFS symptoms recurred in 3 days after surgery. Botulinum toxin type A (BTA) injections were resumed with significant positive effect that can be explained by reduction of one of the factors involved into HFS. Thus, patients with HFS recurrence after vascular decompression may benefit from BTA therapy.

[The DNA methylation profiling in the study and treatment of patients with meningiomas of the craniovertebral junction]

The paper presents the experience of using DNA methylation status in patients with meningiomas of the craniovertebral junction area in a neurosurgical clinic. A clinical case of combined treatment of a patient with meningioma of the craniovertebral junction and the choice of tactics based on the result of DNA methylation analysis of meningioma are described.

[Rosai-Dorfman intracranial histiocytosis: case report and literature review]

Histiocytosis is a group of idiopathic diseases accompanied by metabolic disorders and accumulation of metabolic products in histiocytes. Isolated Rosai-Dorfman histiocytosis of central nervous system is observed in less than 5% of cases. The authors report treatment and follow-up of a patient with intracranial Rosai-Dorfman disease. There were symptoms of lesion of the left cerebellopontine angle and epileptic seizures. Preoperative MRI identified two tumors (posterior cranial fossa on the left and right-sided parasagittal neoplasm). The authors carried out total resection of supratentorial tumor, after 3 weeks - subtotal resection of tumor in posterior cranial fossa. No recurrence after total resection was observed. Irradiation of infratentorial tumor with a total focal dose of 50 Gy after 6 months resulted tumor shrinkage throughout 12 months. Radiotherapy with the same dose was repeated throughout subsequent 12-month follow-up period due to progression of this focus. This treatment had a positive effect, but new skull base foci occurred. The authors emphasize the effectiveness of total resection and lower efficiency of subtotal excision combined with radiotherapy.

[Endoscopic fenestration of arachnoid cyst of posterior cranial fossa through third ventriculostomy]

Arachnoid cysts (AC) are spaces with cerebrospinal fluid covered with arachnoid membrane. Most cysts are supratentorial and only 10-12% of ACs are found in posterior cranial fossa. This disease is usually diagnosed in childhood. In adults, ACs make up 1.4% of all focal lesions. ACs of posterior cranial fossa are often localized behind the cerebellum or in cerebellopontine angle. Most patients with cysts do not have permanent symptoms and should be followed-up. Surgery is indicated for cysts complicated by focal and hydrocephalic-hypertension symptoms. Microsurgical or endoscopic procedures are used. Surgical approach is determined by the closest location of cyst to brain surface. The authors report non-standard surgical approach for giant AC of posterior cranial fossa complicated by obstructive hydrocephalus, intracranial hypertension and visual function impairment. Endoscopic third ventriculostomy was followed by AC fenestration through ventriculostomy. Symptoms disappeared within 6 months after surgery.

[Hypoglossal schwannoma: case report and literature review]

Hypoglossal schwannoma is a rare tumor this frequency approximately less than 5% all non-vestibular schwannomas. Also, it may be sign of neurofibromatosis type 2. Usually, the tong deviation in side of the tumor is the first symptom of the disease. When the tumor size is increased, bulbar disorders and cervico-occipital pain are develop. MRI is the main method of diagnostic. Until the 1970s, mortality after surgical removal reached 50% and was due to bulbar and respiratory dysfunctions. Nowadays, the cause of death remains the same. After introduction stereotactic radiotherapy into clinical practice total removal is not necessary. The purpose of surgery stay is removal of intracranial part of the tumor and decompression of the brainstem (subtotal removal). Radiotherapy or radiosurgery is performed on the intracanal fragment of the tumor. The case of successful surgical treatment of a patient with hypoglossal schwannoma is presented in this article. Subtotal removal was performed via median suboccipital approach. Radiosurgery is planned for residual part of the tumor, located in the hypoglossal nerve channel.

[The causes of late diagnostics of vestibular shwannomas]

AIM

The objective of the present study was to elucidate the causes of late diagnostics of vestibular shwannomas based on the results of the analysis of the medical histories of the patients admitted to the Academician N.N. Burdenko National Medical Research Centre of Neurosurgery for the management of this condition.

MATERIAL AND METHODS

We undertook the retrospective review of a series of 192 cases of vestibular shwannomas in the patients treated based at the N.N. Burdenko National Medical Research Centre of Neurosurgery in 2015. The study included the analysis of demographic characteristics of the patients as well as their anamnestic and clinical data.

RESULTS AND DISCUSSION

A total of 55 (29%) patients were found to have small tumours (Samii T1-T3) whereas 137 (71%) ones presented with giant neoplasms including T4a and T4b tumours (in accordance with the Samii classification) in 63 (33%) and 74 (38%) patients respectively. The duration of the disease from the appearance of its first clinical symptoms up to the establishment of the definitive diagnosis was 41 months on the average. 37 (19%) patients appeared to have paid no attention to the unilateral impairment of hearing. 46 (24%) patients applied for the medical assistance to the therapists and neurologists. 56 (29%) patients had remained for a long time under the supervision of the ENT specialists and surdologists based at the local outpatient facilities.

CONCLUSION

More than 2/3 of the examined patients presenting with vestibular shwannomas apply for the medical assistance at the late stages of the disease. Such situation can be attributed to the low level of oncological alertness among the general population and health providers, the poor awareness of the general practitioners and otorhinolaryngologists about this pathology, the unavailability or inefficient application of the modern neurovisualization technologies, in the first place magnetic resonance imaging. The problems encountered in connection with the performance of screening studies give evidence of the necessity of the introduction of up-to-date otoneurological and audiological investigations as well as the neurovisualization techniques into the everyday clinical practice for the comprehensive examination of all the patients suffering from unilateral hearing loss.

[Surgical approach to resection of vestibular schwannomas following stereotactic radiological treatment. Surgical outcomes and morphological changes in tumors after radiotherapy]

INTRODUCTION

Radiation therapy of small vestibular schwannomas is quite often used as an effective alternative to surgical treatment. At the same time, 2-10% of patients are detected with radioresistant tumors progressing to varying degrees, which is associated with continued tumor growth. In these cases, a decision on surgical resection or re-irradiation of the tumor is made depending on the neurological symptoms, patient's somatic status, and neuroimaging data. Surgical outcomes and intraoperative findings in pre-irradiated patients have been poorly represented in the literature, for which reason we decided to conduct this study. The paper presents a series of patients with vestibular schwannomas who underwent surgical removal of the tumor after radiotherapy.

MATERIAL AND METHODS

A total of 39 patients with vestibular schwannomas after radiotherapy underwent surgery at the Burdenko Neurosurgical Institute in 2007-2017. Of these, 22 patients had a tumor removed after a previously performed combined surgical and radiotherapy treatment (group I), and 17 patients underwent tumor resection after previous radiological treatment (group II). The surgical outcomes were studied depending on various factors, and an analysis of the morphological changes in vestibular schwannomas after radiological treatment was carried out.

RESULTS

In group I, the tumor was resected totally in 18% of patients, almost totally in 5% of patients, subtotally in 68% of patients, and partially in 9% of patients. In group II, the tumor was resected totally in 6% of patients, almost totally in 12% of patients, subtotally in 76% of patients, and partially in 6% of patients. We found that post-radiation changes in patients undergoing surgery led to an increase in the response of neurovascular structures to surgical intervention, development of pronounced fibrosis around tumors, and changes in the structure of tumors that became more solid. As a result, surgical morbidity increased, and the patient's quality of life after surgery deteriorated.

[The efficacy of botulinum therapy in treatment of delayed facial palsy after resection of vestibular schwannoma]

Delayed facial palsy is a complication developing 3 or more days after surgery. The etiology and pathogenesis of this condition has not been fully explored, and there are no treatment standards for it. As in the case of Bell's paralysis, glucocorticosteroids (GCSs) are currently used to treat delayed facial palsy. However, patients with contraindications to GCSs need new therapy modalities.

AIM

We aimed to evaluate the efficacy and safety of botulinum therapy in patients with delayed facial palsy after neurosurgical interventions.

MATERIAL AND METHODS

We examined 33 patients with delayed facial palsy developed 3 or more days after resection of vestibular schwannoma. The main group included 18 patients with contraindications to GCSs who received injections of botulinum toxin A (BTA) into the facial muscles of the healthy side for muscle relaxation. The comparison group consisted of 15 patients who received a course of prednisolone (1 mg/kg/day) for 5-7 days. The efficacy of treatment was assessed using the House-Brackmann scale and Clinical Global Impression Scale. The follow-up period after therapy was 3 months.

RESULTS

Delayed facial palsy was more common in the following cases: the facial nerve was located near the antero-inferior tumor pole; the tumor was adherent to the facial nerve; the tumor extended in the oral direction; the tumor had with unclear borders and was 11 to 30 mm in size. In most patients of both groups, facial muscle palsy developed more than 11 days after surgery. Treatment both in the main and control groups resulted in a significant improvement: complete regression of the facial asymmetry in patients of the main group and comparison groups 3 months after treatment onset was 83.3 and 93.3% (House-Brackmann scale), respectively.

CONCLUSION

Botulinum therapy may be recommended for patients with delayed facial palsy developed after vestibular schwannoma resection, who have contraindications to GCSs.

[Neurosurgery in a patient on dual antiplatelet therapy. Case report and the review of the literature]

INTRODUCTION

A neurosurgical intervention in a patient on dual antiplatelet therapy is a serious challenge for both the neurosurgeon and anesthesiologist..

MATERIAL AND METHODS

The article describes a clinical case of a successful urgent neurosurgical intervention (ventriculoperitoneostomy for obstructive hydrocephalus caused by a large meningioma of the posterior surface of the petrous pyramid) in a patient on dual antiplatelet therapy (DAT) due to a recently placed coronary stent..

CONCLUSION

Given a high risk of coronary stent thrombosis, the surgery was performed in the presence of ongoing DAT. There were no intracranial hemorrhagic complications, but subcutaneous hemorrhagic complications developed. The article discusses the features of managing similar patients whose number is growing.

Dynamics of lagophthalmos depending on facial nerve repair and its intraoperative monitoring in neurosurgical patients

Over 200 patients with acoustic neuromas and over 100 patients with posterior cranial fossa meningiomas are annually operated on at the N.N. Burdenko Neurosurgical Institute. Intraoperative monitoring of the facial nerve function is used in most patients with tumors of the posterior cranial fossa to identify the facial nerve in the surgical wound. If the anatomical integrity of the facial nerve in the cranial cavity cannot be retained, facial nerve repair is performed to restore the facial muscle function. Intraoperative electrical stimulation of the facial nerve has a great prognostic significance to evaluate the dynamics of lagophthalmos in the late postoperative period and to select the proper method for lagophthalmos correction. When the facial nerve was reinnervated by the descending branch or trunk of the hypoglossal nerve, sufficient eyelid closure was observed only in 3 patients out of 17.

Endoscopic assistance in surgery of cerebellopontine angle tumors

During the period of 2010-2012, 33 patients with cerebellopontine angle tumors were operated on at the Burdenko Neurosurgical Institute (Moscow, Russia) using different types of endoscopic assistance. All patients were operated on via the retrosigmoid suboccipital approach in semi-sitting and prone positions. 30° and 70° endoscopes were used during the surgery. Endoscopic assistance allowed us to increase the completeness of tumor removal and to reduce the risk of postoperative complications by retaining the anatomic integrity of cranial nerves and vascular structures in the base of the posterior cranial fossa. These benefits made it possible to maintain and improve quality of life in patients with CPA tumors in the postoperative period.