Supracerebellar Infratentorial Approach Research Articles

Principles of treatment of the pineal region tumors

Background A pineal region tumor is an uncommon deep-seated, heterogeneous group of mass lesions of the brain, and the management strategy of any types of these tumors remains controversial. It is the purpose of this communication to present results of our experience in treating patients with these neoplasms. Methods From 1976 to 1999 about 700 patients with tumors of the pineal region and posterior third ventricle were managed at the Burdenko Neurosurgery Institute. In more than 330 cases the tumor was removed. In this paper we present results of 287 patients with histologically verified pineal region tumors for the period from 1976 to 1999. All of them had verified tumor histology, excluding only five cases in which stereotactic biopsy procedures were uninformative. There are four main groups of tumors: the germ cell tumors—87 (31%); the pineal parenchymal tumors—75 (27%); the glial tumors—77 (27%); and miscellaneous—43 (15%). There were 255 surgical procedures for tumor removal performed in 244 and stereotactically guided biopsies in 61 patients, 168 (58%) with obstructive hydrocephalus who underwent cerebrospinal fluid shunting. Radiation therapy was administered in 145 (51%) and chemotherapy in 16 patients. Follow-up data were collected in 209 cases (80%). Survival was calculated with the Kaplan-Meier product limit method. Results The occipital transtentorial and infratentorial supracerebellar approaches were the most commonly used on our series—138 (54%) and 87 (34%), respectively. In the remaining cases, subchoroidal approach, approach through the fourth ventricle, and the combined approaches were used. A total tumor removal was achieved in 148 operations (58%), subtotal in 74 (29%) and partial in 33 (13%). The projected 5-year and 10-year survival rates for patients with malignant pineal tumors, who received irradiation after tumor resection or underwent radiation therapy alone, were: 95% and 88% for pure germinomas, 80% and 50% for high grade gliomas, 44% and 0% for malignant pineal parenchymal tumors, and 20% and 0% for malignant germ cell tumors, respectively. Conclusions Benign pineal tumors should be cured with surgery alone. Malignant tumors should be treated with aggressive resection followed with irradiation and chemotherapy. Pure germinomas, which are exquisitely radiosensitive, can be cured by conventional radiation therapy alone.

Commentary

BACKGROUND Choroid plexus papillomas (CPPs) are rare intracranial neoplasms, especially in the third ventricle. We report a patient with a posterior third ventricular CPP extending into the pineal that radiographically and clinically presented as a pineal region lesion. CASE DESCRIPTION In a 51-year-old female with headache and upward gaze impairment radiological examination showed a mass in the pineal region obstructing the aqueduct of Sylvius and causing hydrocephalus. After ventriculoperitoneal shunting the tumor was approached through the infratentorial-supracerebellar approach and pathological examination revealed a typical CPP. CONCLUSIONS This case represents an unusual presentation of an intracranial CPP. This entity should be considered an extremely rare cause of a lesion in the pineal region.

Pineal region lesion masquerading choroid plexus papilloma: Case report

Background Choroid plexus papillomas (CPPs) are rare intracranial neoplasms, especially in the third ventricle. We report a patient with a posterior third ventricular CPP extending into the pineal that radiographically and clinically presented as a pineal region lesion. Case description In a 51-year-old female with headache and upward gaze impairment radiological examination showed a mass in the pineal region obstructing the aqueduct of Sylvius and causing hydrocephalus. After ventriculoperitoneal shunting the tumor was approached through the infratentorial-supracerebellar approach and pathological examination revealed a typical CPP. Conclusions This case represents an unusual presentation of an intracranial CPP. This entity should be considered an extremely rare cause of a lesion in the pineal region.

The microsurgical anatomy of the cisternal segment of the trochlear nerve, as seen through different neurosurgical operative windows.

To describe the anatomy of the cisternal segment of the trochlear nerve as seen through different neurosurgical approaches. The cisternal course of ten trochlear nerves was observed in five cadaveric embalmed heads, through the view afforded by the median infratentorial-supracerebellar, the extreme-lateral infratentorial-supracerebellar, and the combined presigmoid-subtemporal transtentorial approaches. The relationships of the trochlear nerve with the surrounding neuro-vascular structures were analyzed. We identified 3 segments of the cisternal trochlear nerve: quadrigeminal, ambient and tentorial. The median infratentorial-supracerebellar approach allowed exposure of the quadrigeminal segment, including the origin of the nerve. The extreme-lateral supracerebellar and the combined presigmoid-subtemporal transtentorial approaches provided visualization of the ambient and tentorial segments of the nerve. The tentorial segment runs in a dural canal contained in the free edge of the tentorium, surrounded by its own arachnoidal sleeve. The trochlear nerve is a very delicate structure that can be easily injured during approaches to the tentorial incisura. Accurate knowledge of its anatomy as seen through different operative windows is helpful in maintaining its integrity during surgery.

Symptomatic pineal cysts: clinical manifestations and management.

Between 1991 and 2000, seven patients presented with symptomatic pineal cysts at our hospital (6 females, 1 male). Average age was 22 years (range 4-33 years). Headache was present in 6 patients, who were subsequently operated on. A scotoma and a transient inferior visual field deficit were minor signs in two patients respectively. A Parinaud syndrome with vertical gaze paralysis was found in none. In one child, paroxysmal pupillary dilatations and contractions ('springing pupils') constituted the only signs and a conservative policy was adopted. Four patients presented with hydrocephalus and were treated by an endoscopic resection of their pineal cysts (one stereotactically, three free-hand). Two other patients presented with a prolonged history of symptoms and signs: headache alone in one, headache with discrete neurological deficits in the other. Ventricles in these two patients were not dilated and therefore an open cyst resection by infratentorial supracerebellar approach was performed. Average follow-up in the six "operated" patients was 29 months (range 12-108 months). All four patients treated by endoscopy, are symptom-free at follow-up, whereas the two who were approached by open surgery, are not. Clinical presentation, radiological evaluation and treatment modalities of pineal cysts are discussed and compared with experiences reported in the literature. It is concluded that pineal cysts in the presence of obstructive hydrocephalus are a clear indication for endoscopy with a rigid endoscope.

上小脳動脈末梢部動脈瘤の臨床像

We report a case of a 71-year-old man who presented a subarachnoid hemorrhage (WFNS grade 1) due to rupture of an aneurysm arising from the hemispheric branch of the superior cerebellar artery (SCA). On the 28th day after admission, the aneurysm was successfully clipped through the infratentorial supracerebellar approach in a Concord position. The patient was discharged with slight cerebellar ataxia 1 month after surgery. We discuss the clinical characteristics of distal SCA aneurysm with a review of literature.

Pineal epidermoid cysts: diagnosis and management.

The results of surgical treatment of epidermoid cysts of the pineal region in six cases are presented. Six patients with pineal epidermoid cysts underwent surgery at the Institute of Neurosurgery "N. N. Burdenko," in Moscow, during the period 1976 to 1995. The duration of the patients' preadmission clinical history varied from 6 months to 2 years (average 1.4 years). Headache, diplopia, and vertigo were the most frequently occurring symptoms. Neurological examination demonstrated papilledema, impaired pupillary reaction, ataxia, and long-pathways deficit; Parinaud's syndrome was found in only one case. Computerized tomography and magnetic resonance imaging constituted the primary diagnostic tools. Surgery was performed using either an infratentorial-supracerebellar approach (two cases) or an occipital-transtentorial approach (four cases). Surgical results can be excellent if a removal, as extensive as possible, is performed using either the supracerebellar or occipital-transtentorial approach.

Infratentorial Approach to Internal Acoustic Meatus

Surgical exposure of internal acoustic meatus via typical suboccipital retrosigmoid craniotomy is limited by inner ear structures that should remain intact if hearing preservation is attempted. Feasibility of supracerebellar-infratentorial approach to the meatus with more medial angle of exposure and with preservation of inner ear structures was studied on fresh cadavers and on computed tomography pictures of temporal bones. Anatomical relationships of internal acoustic meatus and adjacent structures show marked individual variability. When typical retrosigmoid craniotomy is used to expose meatal fundus, significant medial retraction of cerebellar hemisphere is required in 47% of the patients to avoid opening endolymphatic spaces. Internal acoustic foramen and meatus can be exposed via craniotomy situated under transverse sinus, with 10-15 mm downward retraction of cerebellum. Medial extent of craniotomy can be planned on preoperative imaging studies. Infratentorial supracerebellar exposure of internal acoustic meatus allows for more medial angle of surgical approach than standard retrosigmold craniotomy. It can be used when preoperative imaging studies show that anatomical relationships between internal acoustic meatus and inner ear structures would require excessive cerebellar retraction to visualize a whole tumor inside meatus.

Bridging veins on the tentorial surface of the cerebellum: a microsurgical anatomic study and operative considerations.

When using the median infratentorial supracerebellar approach, all or numerous bridging veins over the cerebellar surface must be sacrificed. Such sacrifice potentially causes cerebellar venous infarction, especially when excessive cerebellar retraction is applied. To prevent such potential complications, neurosurgeons must have adequate knowledge of the anatomy of the bridging veins, particularly the hemispheric bridging veins. In 14 cadaveric specimens (26 sides), the number, locations, and tributaries of both the vermian and hemispheric bridging veins between the superior surface of the cerebellum and the tentorium were examined with the aid of an operating microscope. In addition, particular attention was given to the distribution patterns and collateral pathways of the hemispheric bridging veins. The average number of vermian bridging veins per cerebellum was 3.24. The average number of hemispheric bridging veins per side was 1.69, and they were most frequently located in the intermediate third of the hemisphere (59.0%). The distribution patterns of the hemispheric bridging veins were classified into six groups according to the draining patterns of each cerebellar hemisphere. Each hemispheric bridging vein usually had several collateral pathways between other draining veins. The most prominent collateral pathways of the hemispheric bridging veins frequently connected with the vermian bridging veins. Anatomic familiarity with the bridging veins can minimize their intraoperative sacrifice and avert subsequent postoperative complications. This knowledge also assists in planning the best approach to the pineal region.

Operative approaches to the pineal region tumors.

Until the introduction of microsurgery, the surgical treatment of pineal region tumors had very poor results with high mortality and morbidity. However, there have been remarkable improvements with modern surgical technology and advanced knowledge. Now the main surgical approaches to pineal region tumors are the occipital transtentorial approach and the infratentorial supracerebellar approach. Recently the neuroendoscopic approach has been added. The surgical approach and any supplementary treatment should be selected in each case according to the nature of the individual tumor. The forms of treatment practiced by ourselves, including neuroendoscopic surgery, are presented, and the surgical treatments now applied are discussed.

Aneurisma distal de arteria cerebelosa superior. Caso clínico

We report a case of an aneurysm arising from a hemispheric branch of the superior cerebellar artery. The patient was a 68-year-old woman with long-term hypertension and chronic renal failure. She was admitted because of a subarachnoid hemorrhage mainly in the posterior fossa. An angiogram showed a small aneurysm located on a hemispheric branch of the superior cerebellar artery. During the preoperative period, the renal failure was aggravated and the patient suffered from uremic encephalopathy. The operation was carried out 40 days after subarachnoid hemorrhage when she was asymptomatic. The aneurysm was successfully clipped and extirpated by using an infratentorial supracerebellar approach. The postoperative course was complicated by severe hypertension which was finally controlled. The pathological examination was consistent with a saccular aneurysm. The final outcome was entirely satisfying.

Benign tumours of the pineal region: a prospective study from 1983 to 1997

Tumours of the pineal region are rare. Between 1983 and 1997, 128 patients with pineal masses were treated in our institution. Forty-eight (38%) of these were benign. There were 13 patients with meningiomas, 11 with epidermoid tumours, 10 with cystic lesions, five with vascular lesions, five with infective pathology and four with mature teratomas. Allpatientswere managedsurgically.Ventriculo-peritonealshuntswere inserted preoperatively torelieve hydrocephalus. Open surgery thereafter was mostly done through the supracerebellar infratentorial approach. The occipital transtentorial route was preferred for meningiomas. Stereotactic biopsy was used in two patients only. Radical excision of tumours was achievedin 55% ofoperated cases,partialexcisionin 25%.Radiationtherapy,whichwasthe mainstay oftreatmentearlier, was used only in two patients. Stereotactic radiosurgery was used in one patient. All patients followed up were found to be in good or excellent condition.

O-7-102 - Ventricular lavage system

There are three goals in the treatment of pineal tumors: diverting cerebrospinal fluid (CSF) in the case of hydrocephalus, obtaining tissue for diagnosis, and obtaining CSF to identify biological markers. Neuroendoscopy can accomplish all these goals. Two routes can be used to treat pineal tumors. In the transventricular transforaminal approach, the pineal mass is exposed from its anterior aspect. The other route is posterior from a supracerebellar infratentorial approach that resembles the standard surgical approach. It is crucial to recognize that the aqueduct may be compromised and a third ventriculostomy may need to be performed.

V-1-2 - Infratentorial supracerebellar approach to pineal and juxta-pineal region tumors in sitting position

V-1-2 - Infratentorial supracerebellar approach to pineal and juxta-pineal region tumors in sitting position

Surgical management of pineal region tumors.

The authors advocate an aggressive surgical approach to pineal region tumors to provide a definitive histological diagnosis and to facilitate extensive tumor removal. This strategy is based on their surgical experience in 160 operations for pineal region tumors in which operative mortality was 4% with 3% permanent major morbidity. One-third of pineal tumors were benign for which surgery alone was usually curative. A gross total removal was possible in 31 of 107 malignant tumors. The supracerebellar infratentorial approach was preferred in 86% of patients. The tumors displayed considerable histological diversity with germ cell tumors most common (37%), followed by glial cell tumors (28%) and pineal cell tumors (23%). Mixed tumors occurred 15% of the time. Spinal metastases were rare, occurring in less than 10% of patients with malignant tumors. These results with a large series of pineal region tumors demonstrate the safety and efficacy of aggressive pineal tumor surgery.

Cavernous Malformations of the Third Ventricle

CAVERNOUS MALFORMATIONS ARE uncommon lesions that are usually present in the cerebral hemispheres. Less frequently, these malformations are seen in the brain stem, basal ganglia, or paraventricular regions. We report four cases of cavernous malformations of the third ventricle. Patients presented with symptoms of hydrocephalus, memory loss, and signs of hypothalamic dysfunction. Magnetic resonance imaging and computed tomography provided characteristic images of the three lesions preoperatively. All patients underwent direct surgical excision of the malformations. Two patients had a transcallosal, transventricular approach, the third underwent a transcortical, transventricular approach, and the fourth had an infratentorial supracerebellar approach. Postoperatively, the patient with hypothalamic dysfunction has not improved and underwent ventriculoperitoneal shunting. The second patient did well initially; however, 8 days postoperatively, she became comatose and later died. The presumed cause of her deterioration was a hypothalamic venous infarction. The third and fourth patients have returned to their normal neurological baseline. The presenting signs and symptoms, magnetic resonance imaging and computed tomography findings, and treatment options for this rare lesion are discussed and illustrated.

Treatment of nongerminomatous germ-cell tumors of the pineal region.

Germ-cell tumors can be subdivided into germinoma, embryonal carcinoma, choriocarcinoma, endodermal sinus tumor (yolk-sac tumor), and teratoma. They are also distinguished by their production of secreted markers such as alpha-fetoprotein produced in endodermal sinus tumors and embryonal carcinoma or beta-human chorionic gonadotropin, produced by choriocarcinoma and embryonal carcinoma. Germinoma and teratoma produce none of the markers. Because it has been proposed that teratomas may differentiate from multipotent stem cells contained in embryonal carcinoma and are thus lineage related, the presence of markers indicates the presence of a nongerminomatous germ-cell tumor. Nongerminomatous germ-cell tumors are an invariably fatal subgroup within the pediatric pineal region germ-cell tumors. There is no effective, established therapeutic regimen. We report the treatment regimen for three children diagnosed with this highly aggressive tumor entity. The children were first given a course of chemotherapy with bleomycin, etoposide, and cisplatin. This resulted in the normalization of markers and the shrinkage of tumors. These were then removed by the infratentorial supracerebellar approach. Removal was followed by a second course of chemotherapy with vinblastine, ifosfamide, and cisplatin; after which the children underwent radiotherapy. All three children are well and without evidence of residual or recurrent disease 20, 30, and 32 months after surgery, respectively. We propose this therapy regimen for children in whom the markers are positive.

Treatment of Nongerminomatous Germ-Cell Tumors of the Pineal Region

GERM-CELL TUMORS CAN be subdivided into germinoma, embryonal carcinoma, choriocarcinoma, endodermal sinus tumor (yolk-sac tumor), and teratoma. They are also distinguished by their production of secreted markers such as α-fetoprotein produced in endodermal sinus tumors and embryonal carcinoma or β-human chorionic gonadotropin, produced by choriocarcinoma and embryonal carcinoma. Germinoma and teratoma produce none of the markers. Because it has been proposed that teratomas may differentiate from multipotent stem cells contained in embryonal carcinoma and are thus lineage related, the presence of markers indicates the presence of a nongerminomatous germ-cell tumor. Nongerminomatous germ-cell tumors are an invariably fatal subgroup within the pediatric pineal region germ-cell tumors. There is no effective, established therapeutic regimen. We report the treatment regimen for three children diagnosed with this highly aggressive tumor entity. The children were first given a course of chemotherapy with bleomycin, etoposide, and cisplatin. This resulted in the normalization of markers and the shrinkage of tumors. These were then removed by the infratentorial supracerebellar approach. Removal was followed by a second course of chemotherapy with vinblastine, ifosfamide, and cisplatin; after which the children underwent radiotherapy. All three children are well and without evidence of residual or recurrent disease 20, 30, and 32 months after surgery, respectively. We propose this therapy regimen for children in whom the markers are positive.

Experience with the infratentorial supracerebellar approach in lesions of the quadrigeminal region, posterior third ventricle, culmen cerebelli, and cerebellar peduncle.

We report about our experience with the infratentorial supracerebellar approach in 23 patients operated on for lesions located in the posterior part of the third ventricle, quadrigeminal plate, culmen cerebelli and cerebellar peduncle. Three patients had transient worsening of their deficits immediately after surgery. Three patients developed haemorrhages postoperatively requiring surgical evacuation. One of them died. None of the patients developed specific complications which could without any doubt be attributed to the approach. We concluded that in combination with intra-operative CSF drainage and the sitting position the infratentorial supracerebellar approach allows safe access to lesions situated in an area limited by the posterior part of the third ventricle, the fastigium level and both cerebellar peduncles.

Anatomical variations of the straight sinus on magnetic resonance imaging in the infratentorial supracerebellar approach to pineal region tumors

Anatomical variations of the straight sinus (SS) were examined on magnetic resonance imaging (MRI) in 108 control cases and five cases with a pineal region tumor. The data of the latter were compared with the operative findings in the infratentorial supracerebellar approach. In the 108 control cases, the length of the SS was 51 ± 5.2 mm. The angle of the SS to the nasion-tuberculum sellae line, the tuberculum sellae-inion line, and the nasioninion line was 51 ± 6.7°, 44 ± 5.0°, and 47 ± 5.0°, respectively. The SS was inclined 1.4 ± 4.5° posteriorly to the bregma-inion line. The anatomical relationship between the SS and the corpus callosum was subgrouped into three types: in the common type (63%), the extended line of the slope of the SS is tangential to the upper aspect of the splenium of the corpus callosum; in the high-angle type (26%), the extended line is far above the tangent line; and in the low-angle type (11%), the extended line is far below the tangent line. The operative field was restricted by the steeply inclined tentorium in the case of the high-angle type, and the tumor was located much lower than the direction of the operative approach. In contrast, the tumor was easily exposed in the center of the wide operative field in the cases of low-angle type. The present study suggests that the preoperative MRI analysis of the angle of the SS is indispensable before taking the infratentorial supracerebellar approach to the pineal region tumors.