Cerebellopontine Angle Tumors Research Articles

Two Cases of Secondary Hemifacial Spasm: Pathophysiology and Management.

Dear Editor, Classical hemifacial spasm (HFS) has been attributed to an atraumatic pulsatile vascular compression of the facial nerve leading to hyperactivity within the central components of the nerve, alleviated via mobilization of the culprit vessel [1]. In a small subset of patients the cause may be attributed to lesions involving the facial nerve, most commonly benign cerebellopontine angle (CPA) tumors [2,3]. In such secondary HFS the clinical manifestation is usually a tonic facial contraction rather than the intermittent twitching characteristic of common HFS [4,5]. There may, however, also be rare patients with a common presentation of HFS but with an associated CPA tumor [6,7]; the role of neurovascular compression (NVC) in these cases is uncertain. We present 2 cases of secondary HFS, both related to benign CPA tumors.

Effect of Corticosteroids on Facial Function after Cerebellopontine Angle Tumor Removal: A Double-Blind Study versus Placebo

The aim of this study was to assess the effect of corticosteroids administered intra- and postoperatively on the occurrence of facial palsy after a cerebellopontine angle (CPA) tumor resection, and to investigate pre- and intraoperative prognostic factors. A multicenter, prospective, randomized, double-blind and versus-placebo study was conducted between 2006 and 2010. Three hundred and ten patients operated on for a CPA tumor (96% vestibular schwannomas, 4% miscellaneous) were included by five participating centers. The population was stratified into patients with small (≤15 mm CPA on axial MRI views) and large tumors. In each group, patients were randomized to receive corticosteroid (1 mg/kg/day i.v. methylprednisolone intraoperatively and at postoperative days 1-5) or placebo. Steroids did not affect the facial function at postoperative days 1, 8 and 30 in patients with small or large tumors as evaluated by House and Brackmann grading.

The combined microscopic-endoscopic technique for radical resection of cerebellopontine angle tumors.

The combined microscopic and endoscopic technique has shown significant advantages in the management of various lesions through different approaches. Endoscopic-assisted techniques have frequently been applied to cerebellopontine angle (CPA) surgery in the context of minimally invasive craniotomies. In this paper the authors report on the use of the endoscope in the CPA as a tool to increase the extent of resection, minimize complications, and preserve the function of the delicate CPA structures. They also describe a technique of the simultaneous use of the microscope and endoscope in the CPA and dissection of CPA tumors under tandem endoscopic and microscopic vision to overcome the shortcomings of introducing the endoscope alone in the CPA. The reliability of using the microscope alone in dissecting CPA tumors is evaluated, as is the effectiveness of the combined technique in increasing the resectability of various types of CPA tumors. The authors conducted a retrospective analysis of 50 patients who underwent combined microscopic-endoscopic resection of CPA tumors by the senior author over a period of 3 years (February 2011 to February 2014) at Brigham and Women's Hospital, Harvard Medical School. The reliability of the extent of microscopic removal was evaluated with endoscopic exploration. Additional resection was performed with both microscopic and the combined microscopic-endoscopic technique. Endoscopically verified total resection was validated by intraoperative or postoperative MRI. The function of the cranial nerves was evaluated to assess the impact of the combined technique on their function. A tumor remnant was endoscopically identified in 69% of the 26 patients who were believed to have microscopic total resection. The utilization of the endoscopic visualization and dissection increased endoscopically verified total removal to 38 patients, and 82% of these patients had no sign of residual tumor on postoperative imaging. The technique was most effective with epidermoid tumors. There were a total of 17 new cranial nerve deficits in 10 patients. Preoperative fifth cranial nerve deficits improved in 52% and hearing improved in 29% of patients after surgery. This method provides simultaneous microscopic and endoscopic visualization and dissection techniques through skull-base approaches to CPA tumors. It overcomes some of the shortcomings of endoscopic-assisted surgery, further extends the surgical field, and increases the radicality of tumor resection with good functional outcomes.

Comparison of outcomes following complex posterior fossa surgery performed in the sitting versus lateral position

The sitting position during surgery is thought to provide important advantages, yet it remains controversial. We compared surgical and neurological outcomes for patients operated on in the sitting versus lateral position. Technically difficult procedures performed from the years 2001–2008 for complex lesions in the posterior fossa (vestibular schwannomas, other cerebellopontine angle tumors, foramen magnum meningiomas, brainstem cavernomas, pineal region tumors) were included. Outcomes in the two surgical positions were compared for all 243 patients (93 sitting, 38.3%; 150 lateral, 61.7%) and for 130/243 patients with vestibular schwannomas (50 sitting, 38.5%; 80 lateral, 61.5%). Sitting and lateral patient subgroups were clinically comparable. There were no surgical mortalities. The extent of removal and surgical and neurological outcomes were comparable. We found no advantage in surgical or neurological outcomes for use of the sitting or lateral surgical positions in technically difficult posterior fossa procedures. In vestibular schwannoma surgeries facial nerve preservation (House–Brackmann score 1–2) was related to extent of resection but not to surgical position. The choice of operative position should be based on lesion characteristics and the patient’s preoperative medical status as well as the experience and preferences of the surgeons performing the procedure.

Resection of Cerebello Pontine Angle Tumors by Exclusively Endoscopic Approach

Introduction: Endoscopy developed into an important technique in skull base surgery. In the posterior fossa, the use of the endoscope is still limited. The question arises if the endoscope can be used more intensively also in lesions of the posterior fossa.

Fully endoscopic retrosigmoid approach for posterior petrous meningioma and trigeminal microvascular decompression.

Cerebellopontine angle tumor resection and cranial nerve microvascular decompression are usually performed with the aid of the surgical microscope. The endoscope is commonly used as an adjuvant. A retrosigmoid craniectomy is done. Upon dural opening, the endoscope is inserted into the operative field along the petrotentorial junction. Cerebrospinal fluid drainage provides a wider space for introduction of the endoscope and surgical instruments. Traditional microsurgical techniques are used during the entire procedure. A fully endoscopic retrosigmoid approach is a safe and effective procedure for cerebellopontine angle tumor resection and cranial nerve microvascular decompression. • Careful examination of preoperative studies is needed to identify anatomical peculiarities. • Patient positioning: the head must be gently flexed and its vertex gently tilted toward the floor. • Neurophysiologic monitoring and intraoperative navigation. • Craniectomy: partial exposure of the transverse and sigmoid sinuses. • Curvilinear dural incision reflected laterally to minimize the risk of sinus injury. • Opening the cerebellomedullary cistern for CSF drainage and cerebellar relaxation. • Dynamic endoscopy enhances depth perception and must be performed by a team with experience in endoscopic intracranial surgery. • Traditional microsurgical techniques have to be applied during the entire operation. • Multilayer reconstruction, including watertight dural closure. • Meningiomas causing brainstem shift are not suitable for endoscopic resection.

Trigeminocardiac reflex during cerebellopontine angle surgery: anatomical location as a new risk factor

ABSTRACT Aim: Trigeminocardicac reflex (TCR), a brainstem reflex, can be manifested in almost all types of surgery in the head and neck region. Patients & methods: Retrospective review of 125 patients operated on cerebellopontine angle (CPA) tumors according to strict inclusion/exclusion criteria. Results: A total of 14 out of 125 patients showed TCR during CPA tumor operation. In total, 29% of those patients presented with a meningioma located exclusively premeatal, but not retromeatal in the CPA. There was significant relationship between meningiomas subgroups and TCR (Barnard test; p < 0.05). Conclusion: Anatomical location may represent an important, but not yet described risk factor for the TCR having therefore an important role in the understanding of the TCR.

Surgical Outcomes of Cerebellopontine angle Tumors in 50 Cases.

To report our experience with a large series of surgical procedures for removal of cerebellopontine angle (CPA) tumors using different approaches. This was a retrospective analysis of 50 patients (mean age, 49 years) with CPA tumors (predominantly acoustic neuroma) who underwent surgical removal using appropriate techniques (principally a translabyrinthine approach) during a 4-year period. One death occurred during this study. There were nine cases (18%) of cerebrospinal fluid leak, and five patients (10%) were diagnosed as having bacterial meningitis. Complete gross tumor removal was not achieved in four patients (8%). Facial nerve function as measured by the House Brackmann system was recorded in all patients 1 year following surgery: 32% had a score of 1 or 2; 26% had a score of 3 or 4; and 8% had a score of 5 or 6. Other complications included four cases of wound infection. The translabyrinthine approach was predominantly used in our series of CPA tumors, and complication rates were comparable with other large case series.

Magnetic resonance imaging of cerebellopontine angle lesions

Background: Cerebellopontine angle (CPA) tumors are usually benign, and they are divided into extra-axial, intra-axial, extradural, and petrous axis tumors. CPA pathologies can be asymptomatic or it may present with vertigo, tinnitus, or unilateral hearing loss depending upon the site of tumor origin and displacement of the neurovascular structure. Aim and Objectives: To evaluate the role of magnetic resonance imaging (MRI) aided with contrast-enhanced MRI as an imaging modality for diagnosis of CPA lesions. Materials and Methods: Analysis of 36 patients of CPA lesions over a period of 2 years was done. MRI was performed on Siemens 1.5 Tesla MAGNETOM Avanto Machine. Conclusion: There are spectrums of pathologies, which can present with these symptoms, which includes tumors, vascular malformations, and vascular loop compressing vestibulocochlear nerve or mastoid pathology so it is important to investigate the patient by MRI. Contrast-enhanced MRI is the most sensitive investigation in the evaluation of the CPA lesions, its characteristic, and its extent.

Atypical Trigeminal Neuralgia Secondary to Meningioma.

Trigeminal neuralgia is a disorder of the fifth cranial nerve that causes episodes of intense, stabbing, electric shock-like pain that lasts from few seconds to few minutes in the areas of the face where the branches of the nerve are distributed. More than one nerve branch can be affected by the disorder. We report an unusual case of trigeminal neuralgia affecting right side of face presenting atypical features of neuralgia and not responding to the usual course of treatment. The magnetic resonance imaging study of brain revealed a large extra-axial mass involving right cerebellopontine angle region causing moderate pressure effect on trigeminal nerve and brain stem. The aim of this case report is to show a tumor of cerebellopontine angle, presenting clinically as atypical trigeminal neuralgia.

A clinicopathological study of atypical teratoid/rhabdoid tumor with review of the literature

Background: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, aggressive neoplasm of the central nervous system occurring mainly in the early childhood. Objective: The objective of the present study was to study the clinicopathologic features of this newly recognized tumor. Materials and Methods: A retrospective search of pathology files from a series of brain tumors revealed five patients with features of AT/RT. The clinical, radiological and pathological features were analysed. Results: The cases included three boys and two girls with age ranging from 2 years to 15 years. The tumors were located in the infratentorial (three located in the cerebellar hemispheres) and supratentorial areas (two located in the parietal and frontal lobes). One of the cerebellar tumors involved bilateral cerebellopontine (CP) angles, mimicking a primary CP angle tumor (like neurofibroma) with two small deposits in the cerebrum (parietal lobe). Radiologically all the five cases had heterogeneous enhancement with two of them exhibiting cystic change within. Histopathologically, the tumors were composed of rhabdoid cells, undifferentiated small cells, mixed with epithelial, mesenchymal, and neural tumor-like areas. The proportion of each of these elements varied in all the four cases. One of the tumor had predominantly small cells with focal rhabdoid differentiation mimicking a medulloblastoma/primitive neuroectodermal tumor. Conclusion: AT/RT is an aggressive tumor with a varied clinical and pathological profile. The present case series helps in creating an awareness of this complex tumor and stresses the importance of correct diagnosis of this neoplasm that tends to have a bad prognosis.

A misplaced central line: arterial blood gas sample, venous pressure trace and the tip within the lung

SummaryA 24‐year‐old male was scheduled for excision of a cerebellopontine angle tumour. The left internal jugular vein was cannulated preoperatively. The post procedure chest X‐ray showed the tip of the cannula in the left upper zone of the lung; however, blood could be freely aspirated and the transducer trace indicated a mean pressure of 5 mmHg. Blood gas analysis revealed a PaO2 of 13.6 kPa. Angiography confirmed the patients had partial anomalous pulmonary venous drainage with the tip of the catheter situated in the left upper pulmonary vein.

Microsurgical Anatomy of the Labyrinthine Artery and Clinical Relevance.

To describe the origin, the course, and relationships of the labyrinthine artery (LA). Thanks to a colored silicone mix preparation, ten cranial bases were examined using x3 to x40 magnification under surgical microscope. The LA often arose from the meatal loop of the anterior inferior cerebellar artery (AICA) (90%), or basilar artery (10%). The loop was extra-meatal of the internal auditory meatus (IAM) in 30%, at the opening of the internal auditory meatus in 20%, or intra-meatal in 35%. The AICA coursed in closed relationship to the VII and VIII cranial nerves. It coursed between VII and VIII cranial nerve roots in 85%, or passed over the ventral side of both VII and VIII cranial nerve. The average diameter of the LA was 0.2 +/- 0.05 mm. LA was single trunk in 60%, and bi-arterial in 40%. The implication of these anatomic findings for cerebello-pontine angle tumors surgery and neurovascular pathology such as infarction, aneurysm of the LA or the AICA are reviewed and discussed.

Preservation of neurological functions during the extended middle fossa approach operation of small cerebellopontine angle tumors

Preservation of neurological functions during the extended middle fossa approach operation of small cerebellopontine angle tumors

Stereotactic radiotherapy for vestibular schwannoma.

Vestibular schwannomas (acoustic neuromas) are common benign tumours that arise from the Schwann cells of the vestibular nerve.Management options include observation with neuroradiological follow-up, microsurgical resection and stereotactic radiotherapy. To assess the effect of stereotactic radiotherapy compared to observation, microsurgical resection, any other treatment modality, or a combination of two or more of the above approaches for vestibular schwannoma. We searched the Cochrane Central Register of Controlled Trials; PubMed; EMBASE; CINAHL; Web of Science; CAB Abstracts; ISRCTN and additional sources for published and unpublished trials. The date of the search was 24 July 2014. Randomised controlled trials (RCTs) exploring the efficacy of stereotactic radiotherapy compared with observation alone, microsurgical resection or any other possible treatment or combination of treatments in patients with a cerebellopontine angle tumour up to 3 cm in diameter, presumed to be a vestibular schwannoma. We used the standard methodological procedures expected by The Cochrane Collaboration. No studies met the inclusion criteria for this review. There is no high quality evidence in the literature from RCTs to determine whether stereotactic radiotherapy is better than microsurgical resection or observation alone for patients with a vestibular schwannoma. In the absence of such evidence, the treatment method should be chosen on an individual basis, taking into consideration the patient's preferences, clinician experience and the availability of radiotherapeutic equipment. With the growing availability of radiotherapeutic equipment, randomised controlled trials should be undertaken to evaluate the role of stereotactic radiotherapy in comparison with other treatment options.

Unilateral auditory neuropathy spectrum disorder: retrocochlear lesion in disguise?

To investigate whether the aetiology for hearing impairment in neonates with unilateral auditory neuropathy spectrum disorder could be explained by structural abnormalities such as cochlear nerve aplasia, a cerebellopontine angle tumour or another identifiable lesion. In this prospective case series, 17 neonates were diagnosed with unilateral auditory neuropathy spectrum disorder on electrophysiological testing. Diagnostic audiology testing, including auditory brainstem response testing, was supplemented with computed tomography and/or magnetic resonance imaging. Ten of the neonates (59 per cent) showed evidence for cochlear nerve aplasia. Of the remaining seven, four were shown to have another abnormality of the temporal bone on imaging. Only three neonates (18 per cent) were not diagnosed with cochlear nerve aplasia or another lesion. Three computed tomography scans were reported as normal, but subsequent magnetic resonance imaging revealed cochlear nerve aplasia. Auditory neuropathy spectrum disorder as a unilateral condition mandates further investigation for a definitive diagnosis. This series demonstrates that most neonates with unilateral auditory neuropathy spectrum disorder had pathology as visualised on computed tomography and/or magnetic resonance imaging scans. Magnetic resonance imaging is an appropriate first-line imaging modality.

MS-07 * MENINGIOMA OF THE PEDIATRIC SKULL BASE: A REVIEW

Pediatric skull base meningiomas are rare and complex clinical entities. Meningioma is a relatively uncommon brain tumor in children, and only about 27% involve the skull base. Some evidence suggests that these tumors are more likely to be atypical or malignant in children than adults. The absence of female preponderance in pediatric meningiomas is reflected in the skull base subpopulation. Skull base meningiomas in children are most likely to be found in the anterior or middle fossa base, or involving the orbit and optic nerve sheath. Petroclival, suprasellar/parasellar, cerebellopontine angle, cavernous sinus, and foramen magnum tumors are very rare. Meningiomas constitute a small proportion of reported cases of pediatric skull base pathology, and are entirely absent from many case series. Initial gross total resection is consistently associated with superior outcomes. Surgical approaches to the pediatric skull base must take additional factors into consideration including relatively smaller anatomy, immature dentition, incompletely aerated sinuses and air cells, and altered configurations of structures such as the pterional bony complex. Multidisciplinary expertise is essential to optimizing treatment outcomes.

Meningiomas of the pediatric skull base: a review.

Pediatric skull base meningiomas are rare and complex clinical entities. Meningioma is a relatively uncommon brain tumor in children, and only ∼ 27% involve the skull base. Some evidence suggests that these tumors are more likely to be atypical or malignant in children than adults. The absence of female preponderance in pediatric meningiomas is reflected in the skull base subpopulation. Skull base meningiomas in children are most likely to be found in the anterior or middle fossa base, or involving the orbit and optic nerve sheath. Petroclival, suprasellar/parasellar, cerebellopontine angle, cavernous sinus, and foramen magnum tumors are very rare. Meningiomas constitute a small proportion of reported cases of pediatric skull base pathology, and they are entirely absent from many case series. Initial gross total resection is consistently associated with superior outcomes. Surgical approaches to the pediatric skull base must take additional factors into consideration including relatively smaller anatomy, immature dentition, incompletely aerated sinuses and air cells, and altered configurations of structures such as the pterional bony complex. Multidisciplinary expertise is essential to optimizing treatment outcomes.

Cerebellopontine Angle Lipoma in an Asymptomatic Patient: A Case Report

Introduction: Lipomas account for approximately 0.15% of the cerebellopontine angle tumors. Audiometry usually shows unilateral or asymmetric sensorineural hearing loss with low speech recognition index. MRI is the gold standard for diagnosis, with no image enhancing with gadolinium, and positive fat suppression. Treatment is usually conservative and surgery is reserved for clinically untreatable dizziness, trigeminal neurology, and headache.

Surgical Outcome of Cerebellopontine Angle Tumors: A Study of 24 Cases at the Department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University, Dhaka

Background: The cerebellopontine angle is a space defined by the pyramid anterolaterally, the tentorium superiorly, the pons medially and cerebellum dorsomedially. It is difficult to approach for its complication and vital structures.
 Objective: To see the outcome of surgery of cerebellopontine angle tumors at the Bangabandhu Sheikh Mujib Medical University.
 Results: Among the 24 patients 16(66.66%) were males. It was evident that 14(58.33%) belonged to the age group 41-60 years. It was documented that the majority 19(79.16%) of patients had vestibular schwannoma. Among the clinical signs and symptoms the highest group had hearing loss 20(80%). Among 24 patients the tumor was removed completely in 15(62.50%). Among the post operative complications 4(16.66%) developed facial palsy. 2(8.33%) of patients had lower cranial nerve palsy. After operation 1(4.16%) patient died due to aspiration pneumonia.
 Conclusion: Cerebellopontine angle tumor surgery is a very difficulty operation. But at a tertiary hospital, with help of microscope, we can remove the tumor completely.
 Bangladesh Journal of Neuroscience 2014; Vol. 30 (2): 90-95