Tag: Fourth ventricle

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Posterior Fossa Midline Epidermoid Tumors: Role of the Inferior Medullary Velum and a Proposed New Imaging Classification

Neurosurgery 93:112–119, 2023

Posterior fossa midline epidermoid tumors (PFMETs) include the epidermoid tumors of the cisterna magna (CM) and fourth ventricle (FV).

OBJECTIVE: To report tumor epicenter-based classification of PFMETs and its clinical and surgical implications with outcome. METHODS: On retrospective analysis of operated cases of intracranial epidermoid tumors, 19 (N = 19) patients having tumor epicenter within FV, CM, or both were included. Cerebellopontine and prepontine cistern epidermoid were excluded. Tumor location was decided based on preoperative MRI and intraoperative findings. Major complication was defined as new onset or worsening of cranial nerve (CN) deficit, sensory motor impairment, or tracheostomy.

RESULTS: The mean (±SD) age of the patients was 42.0 ± 11.6 years (range 25-61 years), with no sex predilection (male: female: 1:0.9). The most common symptoms were cerebellar dysfunction, headache, vomiting, and diplopia. Common CNs affected were VII, V, lower cranial nerve, and VI. The PFMETs were classified based on tumor epicenter as type 1 (tumor epicenter in CM, n = 4/21.1%), type 2 (FV, n = 5/26.3%), and type 3 (involved CM and FV, n = 10/52.6%). Type 2 tumors had a higher incidence of raised intracranial pressure and only facial nerve palsy as preoperative CN deficit. Type 1 tumors had the least incidence of postoperative major complications. Type 3 tumors were the largest and had a greater incidence of brainstem adhesion and postoperative complications. The tumor size, duration of symptoms, and patient age were higher in patients with brainstem adhesion (5.3 ± 1.0 cm, 21 ± 16 months, 44.1 ± 9.2 years) as against its absence (4.8 ± 1.3 cm, 11.2 ± 7.3 months, 38.2 ± 11.7 years). Inferior medullary velum and tela choroidea have a critical role in tumorogenesis, tumor extension, and brainstem adhesion.

CONCLUSION: PFMETs can be classified into 3 subtypes based on tumor epicenter having clinical and surgical implications. Less aggressive dissection and near total excision in the presence of brainstem adhesion yield favorable outcomes.

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The surgical treatment of tumors of the fourth ventricle

J Neurosurg 128:339–351, 2018

Fourth ventricle tumors are rare, and surgical series are typically small, comprising a single pathology, or focused exclusively on pediatric populations. This study investigated surgical outcome and complications following fourth ventricle tumor resection in a diverse patient population. This is the largest cohort of fourth ventricle tumors described in the literature to date.

METHODS This is an 18-year (1993–2010) retrospective review of 55 cases involving patients undergoing surgery for tumors of the fourth ventricle. Data included patient demographic characteristics, pathological and radiographic tumor characteristics, and surgical factors (approach, surgical adjuncts, extent of resection, etc.). The neurological and medical complications following resection were collected and outcomes at 30 days, 90 days, 6 months, and 1 year were reviewed to determine patient recovery. Patient, tumor, and surgical factors were analyzed to determine factors associated with the frequently encountered postoperative neurological complications.

RESULTS There were no postoperative deaths. Gross-total resection was achieved in 75% of cases. Forty-five percent of patients experienced at least 1 major neurological complication, while 31% had minor complications only. New or worsening gait/focal motor disturbance (56%), speech/swallowing deficits (38%), and cranial nerve deficits (31%) were the most common neurological deficits in the immediate postoperative period. Of these, cranial nerve deficits were the least likely to resolve at follow-up. Multivariate analysis showed that patients undergoing a transvermian approach had a higher incidence of postoperative cranial nerve deficits, gait disturbance, and speech/swallowing deficits than those treated with a telovelar approach. The use of surgical adjuncts (intraoperative navigation, neurophysiological monitoring) did not significantly affect neurological outcome. Twenty-two percent of patients required postoperative CSF diversion following tumor resection. Patients who required intraoperative ventriculostomy, those undergoing a transvermian approach, and pediatric patients (< 18 years old) were all more likely to require postoperative CSF diversion. Twenty percent of patients suffered at least 1 medical complication following tumor resection. Most complications were respiratory, with the most common being postoperative respiratory failure (14%), followed by pneumonia (13%).

CONCLUSIONS The occurrence of complications after fourth ventricle tumor surgery is not rare. Postoperative neurological sequelae were frequent, but a substantial number of patients had neurological improvement at long-term followup. Of the neurological complications analyzed, postoperative cranial nerve deficits were the least likely to completely resolve at follow-up. Of all the patient, tumor, and surgical variables included in the analysis, surgical approach had the most significant impact on neurological morbidity, with the telovelar approach being associated with less morbidity.

 

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Endoscopic Transventricular Transaqueductal Magendie and Luschka Foraminoplasty for Hydrocephalus

Endoscopic foraminoplasty for Hydroc

Neurosurgery 74:426–436, 2014

Routinely, hydrocephalus related to fourth ventricular outlet obstruction (FVOO) has been managed with ventriculoperitoneal (VP) shunting or endoscopic third ventriculostomy (ETV). Few reports on Magendie foraminoplasty exist, and Luschka foraminoplasty has not been described.

OBJECTIVE: To present an alternative technique in the management of FVOO via an endoscopic transventricular transaqueductal Magendie and Luschka foraminoplasty and to discuss the indications, technique, findings, and outcomes.

METHODS: Between 1994 and 2011, all patients who underwent endoscopic Magendie and Luschka foraminoplasty were analyzed.

RESULTS: A total of 33 Magendie (28) and/or Luschka (5) foraminoplasties were performed in 30 patients. Twenty-three were adult and 7 were pediatric patients. The etiology of the FVOO was divided into primary etiologies (congenital membrane in 5 and atresia in 2) and secondary causes (neurocysticercosis in 14 patients, bacterial meningitis in 9). Fifteen (50%) had previously failed procedures. Intraoperative findings that led to Magendie/Luschka foraminoplasty were ETV not feasible to perform, nonpatent basal subarachnoid space, or primary FVOO. Minor postoperative complications were seen in 3 patients. Only 26 patients had long-term follow-up; 17 (65.3%) of these had clinical improvement and did not require further procedures. Nine (34.7%) did not improve. Eight required another procedure (7 shunts, and 1 endoscopic procedure). One patient died.

CONCLUSION: Flexible neuroendoscopic transventricular transforaminal Magendie and Luschka foraminoplasty is feasible and safe. These procedures may prove to be viable alternatives to standard ETV and VP shunt in appropriate patients. Adequate intraoperative assessment of ETV success is necessary to identify patients who will benefit.

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Transcerebellomedullary fissure approach to lesions of the fourth ventricle: less is more?

TCMF

Acta Neurochir (2013) 155:1011–1016

The transcerebellomedullary fissure (trans-CMF) approach is safe and effective. Nevertheless, previous research documented a few differences in the use of this approach with regard to the opening portion of the fissure and roof of the ventricle. Here, we present a series of patients with fourth ventricular lesions and our experience using the trans-CMF approach.

Methods Fifty patients who underwent the trans-CMF approach were analyzed. The tela choroidea was simply incised in 32 patients: 27 unilaterally and 5 bilaterally. Both the tela and inferior medullary velum were cut in 18 patients: 16 unilaterally and 2 bilaterally. Unless the tumor extended below the C1 level, C1 was preserved intact. Brainstem mapping (BSM) and corticobulbar tract (CBT) motor-evoked potential (MEP) monitoring were used.

Results Gross total removal was achieved in 41 (82 %) cases, and sub-total removal was achieved in 9 (18 %) cases. Two deaths occurred 1–2 months postoperatively because of pulmonary complications. Four patients developed temporary mutism, all of whom underwent the bilateral trans-CMF approach (this rate is significantly higher than that of the unilateral approach, P<0.05). No permanent neurological deficit occurred.

Conclusion The trans-CMF approach provides excellent access to fourth ventricular lesions without splitting the vermis. The opening portion of the fissure and roof of the ventricle should be determined by the location, extension and size of the lesion. In most cases, the unilateral trans- CMF approach with only a tela choroidea incision is adequate; this procedure is mini-invasive and possibly prevents postoperative mutism.

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Comparison of Tonsillar Retraction and Resection in the Telovelar Approach

Neurosurgery 66[ONS Suppl 1]:ons30-ons40, 2010 DOI: 10.1227/01.NEU.0000348558.35921.4E

OBJECTIVE: To compare the effectiveness of the telovelar approach with tonsillar manipulation for approaching the recesses of the fourth ventricle.

METHODS: A telovelar approach was performed in 8 injected cadaveric heads. Areas of exposure were measured for the superolateral and lateral recesses. Horizontal angles were evaluated by targeting the cerebral aqueduct and medial margin of the lateral recess. Quantitative comparisons were made between the telovelar dissections and various tonsillar manipulations.

RESULTS: Tonsillar retraction provided a comparable exposure of the superolateral recess with tonsillar resection (26.4 ± 17.6 vs 25.2 ± 12.5 mm2, respectively; P = .825). Tonsillar resection significantly increased exposure of the lateral recess compared with tonsillar retraction (31.1 ± 13.3 vs 20.2 ± 11.5 mm2, respectively; P = .002). Compared with tonsillar retraction, the horizontal angle to the lateral recess increased after either contralateral tonsillar retraction (22.7 ± 4.8 vs 36.7 ± 6.5 degrees) or tonsillar resection (22.7 ± 4.8 vs 31.5 ± 7.6 degrees; all adjusted P < .01). The horizontal angle to the cerebral aqueduct increased significantly with tonsillar resection compared with tonsillar retraction (17.6 ± 2.3 vs 13.2 ± 2.8 degrees; P < .001)

CONCLUSION: Compared with tonsillar retraction, tonsillar resection provides a wider corridor to, and a larger area of exposure of, the cerebral aqueduct and lateral recess. Contralateral tonsillar retraction improves access to the lateral recess by widening the surgical view from the contralateral side.

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