Total Tumor Removal Research Articles

Endoscopic endonasal removal of laterally extended clival chordoma using side-viewing scopes

The transsphenoidal approach provides a straight and direct route to the clival chordoma, but has limitations for removing the tumor compartment extending laterally into the space posterior to the paraclival internal carotid artery. To overcome the limitations, a side-viewing endoscope and malleable/steerable instruments were employed. Four clinical cases with clival chordoma extending into the retro-carotid space were analyzed for extent of resection, complications and clinical outcome. The retro-carotid tumor compartment was removed in all cases under 30- and 70-degree side-viewing endoscopes using a malleable dissector and/or steerable forceps, resulting in gross total removal of the entire tumor. Single cases were complicated by transient abducens nerve palsy and cerebrospinal fluid leakage, which required surgical revision. All patients have been symptom free without tumor recurrence during the mean postoperative follow-up of 21.3 months. Though a longer follow-up is needed to evaluate its effectiveness in long-term tumor control, the surgical maneuver using the side-viewing endoscope is effective for removing laterally extended clival chordomas.

Image fusion neuronavigation- guided transsphenoidal microsurgery for pituitary adenomas

Objective To evaluate the value of image fusion neuronavigation in transsphenoidal microsurgery for pituitary adenomas of recurrence or associated with poorly pneumatized sphenoid sinus (PPSS). Method During a four - year period, neuronavigation - guided transsphenoidal microsurgery was performed for selected twenty - four patients with pituitary adenoma. Among them, eighteen cases underwent repeat transsphenoidal surgery;six cases associated with PPSS received primary operation. The fused images of magnetic resonance imaging(MRI) and computed tomography(CT) were utilized for preoperative planning and introperative guidance. The extent of tumor removal was determined by the comparative analysis of preand post - operative radiological materials. Results All lesions were accurately oriented and approached with the aid of neuronavigation. Fused images allowed simultaneous visualization of the bony structures (sphenoid wall and cavity,sellar floor) and soft tissue( tumor, internal carotid artery,cavernous sinus) as well as the relationship between them. Total tumor removal was achieved in 20 patients, subtotal and part tumor removal in 2 patients respectively. There was no intracranial hemorrhage and infection. Postoperative transient diabetes insipidus occurred in 7 patients, cerebrospinal fluid leakage and occulomotor palsy in 1 patient respectively. No recurrence was found in the 22 patients with total or subtotal tumor removal during an average 17.6 months follow - up period. ConclusionsImage fusion neuronavigation is beneficial to transsphenoidal microsurgical removal of either recurrent pituitary adenomas or pituitary adenomas associated with PPSS. It may provide accurate guidance for the procedure, avoid complications due to misdirection and achieve a more radical tumor removal. Key words: Image fusion; Neuronavigation; Transsphenoidal; Pituitary adenoma

Hypoglossal nerve schwannoma with intratumoral hemorrhage

Intratumoral hemorrhage of hypoglossal schwannoma is very rare. A 37-year-old man was admitted to our hospital with severe headache and gait disturbance. Radiologic examination revealed subarachnoid hemorrhage and a well-circumscribed enhanced lesion compressing the medulla oblongata. Gross total removal of the intracranial tumor was performed. Histopathological examination revealed the characteristic features of a schwannoma. The tumor had several hemorrhagic areas and numerous hyalinized blood vessels. Although the mechanism of hemorrhage from schwannomas is unclear, it is hypothesized that tumor vessels showing focal sinusoidal dilatation and hyaline thickening of the walls lead to spontaneous thrombosis with consequent necrosis, and often hemorrhage.

Retrosigmoid approach for meningiomas of the cerebellopontine angle: results of surgery and place of additional treatments

Meningiomas of the cerebellopontine angle (CPA), although homogenous in terms of location, present different surgical challenges depending on their site of dural origin and extension. Complete tumor resection sometimes leads to high morbidity. The objective of this work is to evaluate the results of surgery and the place of additional treatments. In a series of 115 patients with CPA meningiomas, we retrospectively studied 69 patients operated on between 1994 and 2007 using a retrosigmoid approach. Clinical presentation, operative findings and functional outcome were reviewed for a mean follow-up time of 36months. Usual presentation was hearing loss associated with gait disturbance (50%) and vertigo (35%). Preoperative cochlear evaluation was abnormal in 40% of the cases. Most tumors (90%) originated on the posterior face of the petrous part of the temporal bone. In one-third of the cases, the meningioma had invaded the internal acoustic meatus. Total or subtotal tumor removal was achieved in 91% of patients without perioperative mortality. Fourteen patients received additional treatment with radiotherapy or radiosurgery for a small residual tumor, often deliberately left in place to reduce operative morbidity. At long-term follow-up, facial nerve function was preserved in 91% of the cases. Hearing worsened in 17% of patients. The tumor recurred in only one case. The retrosigmoid approach is a safe surgical procedure. The modern management of CPA meningiomas should achieve as complete a resection as possible within reasonable limits, considering that a small residual tumor can be controlled fairly easily with radiosurgery for a relatively long time.

Facial nerve function after vestibular schwannoma surgery

The object of this study was to evaluate long-term postoperative facial nerve (FN) function in patients undergoing vestibular schwannoma (VS) surgery. The authors retrospectively reviewed the clinical course of patients affected by isolated VSs with normal preoperative FN function, with no previous surgical or radiotherapeutic treatment, and who underwent surgery between 1987 and 2007. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) scale. The minimum postoperative follow-up was 12 months. Among the 1550 patients surgically treated at the authors' center, 1151 matched inclusion criteria for the present study. The FN was anatomically interrupted in 48 cases (4.2%), and 51 patients (4.4%) underwent subtotal tumor removal and were considered separately. Among the 1052 patients with anatomically preserved FNs and total tumor removal, 684 (65%) enjoyed postoperative HB Grade I or II and 309 (29.4%) enjoyed Grade III, with the remaining 59 cases (5.6%) suffering unsatisfactory results (HB Grades IV-VI). As expected, FN function results deteriorated in cases of larger tumors. The main factor influencing postoperative FN function was tumor size. Although there was a progressive deterioration in FN function outcome in relation to tumor size, a cutoff point between satisfactory and unsatisfactory results could be identified at around 2 cm in maximum extrameatal tumor diameter, with the "optimal size" for surgery identified at < 1 cm. This finding emphasizes the importance of an early diagnosis and should be kept in mind when selecting the correct timing for VS removal. For small lesions, the results following a middle cranial fossa approach were significantly worse as compared with those following the translabyrinthine and retrosigmoidretrolabyrinthine approaches.

Management of complex tympanojugular paragangliomas including endovascular intervention

To identify complex cases of tympanojugular paraganglioma (TJP) and to analyze their management and surgical outcome. To present strategy and guidelines on how to deal with the perioperative complicating factors. Retrospective analysis. We retrospectively studied 212 TJP patients to identify the complex cases and analyzed their management and surgical outcome. The criteria for complex TJP are: 1) very large size; 2) large intradural extension (IDE); 3) extension to the cavernous sinus, foramen magnum, and clivus; 4) significant involvement of the internal carotid artery (ICA); 5) a solitary ICA on the lesion side; 6) involvement of the vertebral artery; 7) dominant or unilateral sigmoid sinus on the lesion side; 8) bilateral or multiple paragangliomas; and 9) recurrence. Sixty patients were classified as complex. Forty-five patients had tumors with IDE. Twenty patients with tumor involving ICA underwent preoperative endovascular intervention. Two patients had a solitary ICA and two others unilateral sigmoid sinus on the lesion side. Thirteen patients had multicentric tumors, and three patients had bilateral ones. The main procedure was the infratemporal fossa approach type A. Total removal was achieved in 46 patients, and five of them experienced recurrence. It is essential to carefully investigate the hemodynamics of the brain in planning surgery. A proper preoperative endovascular intervention facilitates gross total tumor removal. In bilateral paragangliomas, lower cranial nerves' function should be preserved at least unilaterally. Staged removal is recommended for a tumor with a large intradural component.

Juvenile Nasopharyngeal Angiofibroma with Intracranial Extension

To provide a critical evaluation of the historical evolution of the surgical treatment of juvenile nasopharyngeal angiofibroma (JNA) with intracranial extension. Case series with chart review. Skull base multidisciplinary group at the Instituto de Neurologia de Curitiba, Brazil. From 1988 to 2000, the multidisciplinary skull base group surgically treated 67 adolescent boys with JNA, 20 of whom presented with intracranial extension. All patients presented involvement of the cavernous sinus, and 5 of them spread into the orbit. Before 2008, the authors combined microscopic-endoscopic techniques. After this period, the surgical approach used was facial degloving, associated with purely endoscopic technique patients. Total tumor removal was achieved in 17 cases in the first surgery. In this series, the intracranial extension was extradural in all cases. There was only 1 case of cerebrospinal fluid leakage, which was promptly identified and treated. There was no mortality or permanent morbidity. Radical removal of large JNA may be difficult because of its extreme vascularity and extension to the cavernous sinus, orbit, middle and anterior fossa. Nevertheless, most of JNA with intracranial extension can be resected in the first operation with minimal morbidity through a facial degloving and further combination of expanded endoscopic endonasal approaches.

Chondroblastoma of the temporal bone

Chondroblastomas are highly destructive tumors that are derived from immature cartilage cells. The occurrence of this tumor in the temporal bone or skull base is uncommon. Approximately 70 cases have previously been reported, several of which have involved the temporomandibular joint (TMJ). We report here the case of a 67-year-old woman who presented with right-sided mixed hearing loss, a right external auditory canal mass, ear fullness, otalgia, blood-stained otorrhea, and pain around the TMJ, associated with difficulty in opening the mouth. CT and MRI revealed a mass involving the TMJ, infratemporal fossa, and pterygopalatine fossa. The patient underwent tumor resection via an infratemporal fossa approach type B. Gross total tumor removal was achieved, with no facial nerve paralysis or other complications observed after surgery. No recurrence or residual tumors were observed on CT and MRI, even after 7.5 years of follow-up. We conclude that temporal bone chondroblastomas are extremely rare and aggressive, but the outcome after appropriate surgical treatment is favorable. From the review, it may be particularly important to deal with tumors that involve the TMJ, which could affect the long-term outcomes, as well as tumor recurrence.

Benefit of 1.5-T intraoperative MR imaging in the surgical treatment of craniopharyngiomas

As low-field magnetic resonance imaging (MRI) has very limited significance for intraoperative control of total tumor removal (TTR), we examined the influence of 1.5-T MRI, incorporating higher resolution into the intraoperative strategy of craniopharyngioma surgery. Surgery with intraoperative imaging was performed in 25 selected patients in whom tumor resection was anticipated to be difficult according to pre-operative findings. Intraoperative MRI confirmed the intended extent of tumor removal in 15 patients (14 TTRs, one intended incomplete removal, while a second procedure was scheduled due to complex shape). Misinterpretation was false positive or negative in one patient each. The extent of removal was not achieved as expected in eight patients (expectation: seven TTRs, one incomplete removal). In three patients, the expected TTR was achieved by resuming surgery. In another case, that goal was accomplished by performing an unscheduled second procedure. In total, by using intraoperative imaging, the rate of TTR was increased by 16% (four patients), leading to 80% in the entire series. Compared with the literature, the rate of new ophthalmologic and endocrine deficits is acceptable; the rate of other surgical complication is slightly higher but not directly caused by intraoperative imaging. Intraoperative 1.5-T MRI provides benefits because of good early prediction of TTR (sensitivity, positive predictive value: 93.8%; specificity, negative predictive value: 88.9%) and a low rate of false-positive results. Moreover, extended resection of remnants visualized is enabled and helps to increase the rate of TTR but does not exclude recurrence.

Surgical management of vestibular schwannoma in elderly patients

This study aimed to evaluate surgical results of vestibular schwannoma in elderly patients using a retrospective study in a Quaternary Neurotology and Skull Base Referral Center setting. The data of 232 elderly patients (above 65 years) operated on for vestibular schwannoma in the period between April 1987 and July 2009 were reviewed. Most patients were operated on via translabyrinthine approach (TLA) using transapical extension for large tumors. Other approaches used were retrosigmoid, middle cranial fossa, and transcochlear. Total tumor removal was achieved in the majority of cases, while planned subtotal removal was used in specific occasions. Postoperative complications included facial nerve palsy, other cranial nerves injury, persistent instability, intracranial hemorrhage, CSF leak, meningitis, and death. Patients were followed after surgery for tumor regrowth or occurrence of complications. The results showed low rate of morbidity and mortality. Despite that complete removal is the main target of the surgery; adoption of subtotal removal in selected cases can improve postoperative facial nerve results and reduce the duration of surgery.

Olig2 is useful in the differential diagnosis of oligodendrogliomas and extraventricular neurocytomas

A 42-year-old woman had suffered from headaches since April 2009. Computed tomography revealed a tumor with marked calcification in the left frontal lobe adjacent to the left anterior horn of the lateral ventricle. T1-weighted gadolinium-enhanced magnetic resonance imaging showed a well-enhanced tumor at the lesion. Dynamic methionine positron emission tomography showed no delayed methionine attenuation. Initial preoperative diagnosis was extraventricular neurocytoma (EVN). However, oligodendroglioma was determined upon a second diagnosis. The patient underwent total tumor removal. Hematoxylin and eosin staining showed the characteristic fried egg-like cells, round nuclei, and immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein, synaptophysin, neuronal nuclear antigen, microtubule-associated protein 2 and Olig2. The MIB-1 labeling index was 20%, which suggested malignancy. Although these findings demonstrated that the tumor had glioneuronal character, it was difficult to differentiate between EVN and oligodendroglioma. There have been reports that Olig2 immunohistochemistry is generally positive in cases of oligodendroglioma, but not in cases of neurocytoma. We completed the diagnosis as oligodendroglioma. Subsequent electron microscopy results presented oligodendroglial but not neuronal characteristics. We concluded that Olig2 is useful in the differential diagnosis of oligodendrogliomas and EVNs.

Subependymal giant cell astrocytoma with oncocytic change

A 49-year-old woman presented with a history of periodic episodes of nausea and vomiting starting in 2006. In June 2009, the patient lost consciousness and was transported to our hospital. Head computed tomography (CT) revealed hydrocephalus caused by an enhancing mass lesion with calcification located in the right lateral ventricle around the foramen of Monro. Total tumor removal was performed. Histologic findings revealed fibrillated spindle tumor cells and giant tumor cells with abundant cytoplasm. The spindle tumor cells were immunoreactive for GFAP and S-100 protein, but none of the giant tumor cells were immunoreactive for GFAP or S-100 protein. Electron microscopic examination revealed abundant mitochondria in the tumor cell cytoplasm. According to these findings, this tumor was diagnosed as subependymal giant cell astrocytoma (SEGA) with oncocytic change, which is extremely rare.

Spinal Intradural Extramedullary Cavernoma Presenting with Intracranial Superficial Hemosiderosis

A case of intradural extramedullary cavernous angioma is presented with headache, dizziness, and bilateral sensorineural hearing loss caused by an intracranial superficial hemosiderosis. It was incidentally found in a patient with a 3-month history of sustained headache, dizziness and a 3-year history of hearing difficulty. The neurological examination was unremarkable in the lower extremity. MR images showed an intracranial superficial hemosiderosis mostly in the cerebellar region. Myelography and MR images of the thoracolumbar spine revealed an intradural extramedullary mass, which was pathologically proven to be a cavernous angioma. T12 total laminoplastic laminotomy and total tumor removal were performed without any neurologic deficits. The patient's symptoms, including headache and dizziness, have been absent for three years. Intradural extramedullary cavernous angioma can present with an intracranial superficial hemosiderosis as a result of chronic subarachnoid hemorrhage.

Microsurgical removal of olfactory groove meningiomas

To explore an effective method for further improving the surgical results of treatment of olfactory groove meningiomas. Sixty seven cases of olfactory groove meningiomas were treated by microneurosurgery, among which fifty seven were de novo cases, eight were recurrent tumors and the other two re-recurrent cases. Modified Derome approach was used in 12 cases, bilateral subfrontal approach in 28 cases, modified pterional approach in 21 cases and unilateral subfrontal approach in six cases. Tumors were resected microsurgically with radical removal of invaded dura, bone, and paranasal sinus mucosa. Reconstruction was performed in patients with skull base defect. Simpson grade I removal was accomplished in 59 cases, grade II in seven cases and grade IV in one case. Among 57 patients with de novo tumor, Simpson I resection was accomplished in 54 cases. Postoperative rhinorrhea and intracranial infection occurred in one case and was cured after temporal lumbar CSF drainage and antibiotic therapy. Two patients (2.9%) died within one month after operation, i.e.one aged patient of heart failure and the other of severe hypothalamus complication. Forty seven patients (72.3%) were followed up from one to ten years with an average of five years and four months. With the exception of two cases died, among the alive 45 patients, there were only three patients with tumor recurrence, which had undergone Simpson II or IV tumor resection. No recurrence was found in cases with Simpson I tumor removal. Previous blurred vision was not improved in three patients, hemiparalysis in two patients, and the other patients recovered well, resuming previous jobs or being able to take care themselves. Total tumor removal (Simpson I) should be the surgical goal for treatment of olfactory groove meningiomas, especially for de novo cases. An appropriate approach is fundamental in the effort to remove an OGM totally. Appropriate anterior skull base reconstruction with vascularized material is important and mandatory.

Combined Microsurgical and Endoscopic Removal of Extensive Suprasellar and Prepontine Epidermoid Tumors

Epidermoids tend to grow around and adhere to critical neurovascular structures, but total or maximal tumor removal is recommended to reduce the risk of recurrence. We describe our method of combined microscopic and endoscopic resection for extensive epidermoid tumors. Thirteen patients with epidermoid tumors located in the suprasellar, prepontine, or surrounding cisterns underwent microsurgical resection with a rigid endoscope and a high definition camera system. An anterior petrosal and/or a pterional approach was selected in 6 patients and a lateral suboccipital approach in 7 patients. An endoscope was used with the operating microscope to remove 6 tumors through the anterior petrosal and/or pterional approaches in 5 cases and the lateral suboccipital approach in 1 case. An endoscope was used to confirm microscopic removal in 5 patients. Total removal was achieved in 5 patients and subtotal removal in 8 patients. We recommend the combined microsurgical and endoscopic approaches to achieve maximal resection of extensive suprasellar and prepontine epidermoids.

Editorial: Acoustics and hydrocephalus

This retrospective study regarding management options in patients with hydrocephalus associated with vestibular schwannomas (VSs) comes from a center with a remarkably large surgical experience treating this tumor type.1 Their surgical technique has been exquisitely developed over many years, and is uniform among colleagues in their institution. They receive worldwide referrals and treat a greater than usual number of larger VSs. This helps to account for their significant experience with hydrocephalus in patients with this specific tumor; that is, larger tumors often present for a longer than usual period of time. Their consecutive series of 400 patients was collected over a 6-year period (an average of more than 66 cases per year). Their overall results with complete tumor removal and percentage of saved facial nerve function and preserved hearing is among the best reported in the medical literature.3 In evaluating the superb results herein reported (“The general and functional outcome of surgery showed no correlation to the presence of preoperative hydrocephalus.”), the above statements and the fact that these patients undergo operation in the semisitting position, with very experienced neuroanesthesiologists performing the anesthesia, must be taken into account. In most centers around the world, patients undergo this surgery in a supine (flat or slight reverse Trendelenberg) position, with the head turned or in a lateral position.2 Patients with hydrocephalus, even those with modestly elevated intracranial pressure (ICP), at induction of anesthesia can have their ICP severely elevated, and this may be obviated in the sitting position. Modest or marked elevation of the ICP will often make it more difficult to perform the surgical procedure safely and to accomplish the removal of the entire tumor while sparing the critical cranial nerves. My own recommendation (and I believe the procedures that are followed in most centers where patients are not operated on in the sitting position) would be as follows: 1) patients with symptomatic hydrocephalus accompanied by elevated ICP would have an external ventricular drain (EVD) placed, and when the ICP normalized in 1 or 2 days, they would be taken to surgery. The EVD would be left in place postoperatively, and then the patient would be gradually weaned from the drain. If weaning was not possible (as the authors recommend), a ventriculoperitoneal shunt would be placed. 2) Patients with asymptomatic hydrocephalus and those with normalpressure hydrocephalus (NPH) symptomatology would have an EVD placed at the beginning of anesthesia, the pressure would be kept in a normal range during the operation to mitigate elevated pressure transmission to the posterior fossa, and then after surgery the drain would be left in, and then usually removed in 1–2 days, as long as the clamped pressure permitted this. With this approach, the incidence of permanent hydrocephalus (obstructive or communicating), and CSF leakage would probably be similar to that reported herein. The authors emphasize the advantages of avoiding an EVD, but the desirability of this EVD approach in the patient who undergoes surgery in the recumbent position would be a less complex surgical procedure, with a better chance of total tumor removal, with sparing of critical cranial nerves. This is not the type of evaluation that is compatible with the design of a prospective trial. Indeed, it is a report most appropriately summarized for clinical recommendations based on clinical experience. There continues to be an important place for such published reports, and the expectation of prospective or double-blind trials in this arena is inappropriate. That is the reason my editorial contains remarks based on clinical experience, and why the recommendations the authors make based on their own observations in their own unique environment are of great value. I seriously doubt that their proposed design of a prospective trial will be successful, particularly in light of their proposal to obtain lumbar CSF to measure protein levels both before and after tumor removal: obtaining CSF in a patient with a large posterior fossa tumor remains an unquestionably dangerous procedure.

Concomitant Cerebellum Subdural Seeding and Spinal Epidural Metastasis of Pineal Germinoma

Pineal region lesions in adults brings up various considerations. Central nervous system (CNS) germinoma should be considered. Cerebrospinal fluid (CSF) seeding is the main route of CNS germinoma dissemination. The spinal seeding rate has been reported to be 5-20%. Spinal epidural metastasis from CNS germinoma is very rare. Only one case report had been reported in the literature. Here, we report a 43 year-old man with pineal germinoma developing concomitant cerebellum subdural and spinal epidural metastasis 2 years after the right occipital transtentorial approach with total removal of the tumor and radiation. The literature reviews of the seeding mechanism and treatment modality will be discussed.

Efficacy of surgical treatment for cavernous sinus hemangiomas

to analyze the efficacy of surgical treatment for cavernous sinus hemangiomas (CSH). the data from 29 surgical CSH patients, 7 males and 22 females, aged 52 ± 9 years old, at our department were collected from 2003 to 2009 and analyzed retrospectively. The main presenting symptoms included headache (n = 15), impaired visual acuity (n = 9), diplopia (n = 7), ptosis (n = 2), facial paresthesia (n = 6), hemiparesis (n = 1) and infrequent menstruation (n = 4). MRI was major preoperative modality. All patients underwent craniotomy via frontotemporal approach with or without orbitozygomatic osteotomy. The tumor was removed through intradural approach in all patients. total removal was achieved in 14 (48.3%) patients. And 13 (44.8%) and 2 (6.9%) patients had subtotal and partial procedures respectively. No postoperative death occurred. Follow-up study of 3 months to 6 years was conducted in 27 patients (93%). All headaches were relieved postoperatively. The central nervous symptoms improved in 12 patients. The neuroendocrine symptom had no improvement. The most common surgical complications included impaired visual acuity (n = 2, 6.9%), paralyses of oculomotor nerve (n = 17, 58.6%), abduct nerve (n = 8, 27.6%) and trigeminal nerve (n = 4, 13.8%). A MRI follow-up of 1 - 6 years was obtained in 16 patients without recurrence. surgery is an effective management strategy for CSH. However, total tumor removal remains difficult. Complications such as cranial nerve injury are still rather troublesome.

Trigeminal schwannomas: experience with 57 cases and a review of the literature

Trigeminal schwannoma is a mostly benign tumor that can be cured by complete resection. Over the last few decades, several pioneers have developed surgical approaches enabling the total removal of such tumors. We analyzed 57 patients who underwent radical surgery, including 45 patients who underwent skull base surgery as their initial treatment, for removal of trigeminal schwannomas. Here, we report the surgical management of these cases. Since 1990, all such patients have been treated using three main types of middle fossa skull base approaches, which minimize the exposure of the brain: the anterior transpetrosal approach, subtemporal interdural approach (Dolenc), or a combination of these approaches. Before 1990, total tumor removal was achieved in only three of eight patients (38%). After 1990, the tumors were totally removed in 43 patients (90%) and were nearly completely removed in an additional three patients (6%). Among the patients who underwent skull base surgery as their initial treatment, a complete resection was achieved in 93% (42/45 patients) of the cases. However, total surgical removal after surgery and Gamma knife surgery was very difficult because of dense adhesions to the brain stem and cranial nerves. No surgery-related mortalities occurred in this series, and the individual KPS scores were more than 90% among the patients who underwent skull base surgery. No recurrences requiring additional surgery have occurred after an average follow-up period of 4.9 years. Most of the trigeminal schwannomas could be removed totally and safely during a single operation after the introduction of skull base surgery. Therefore, radiosurgery should not be applied as the treatment of first choice for younger patients. A correct anatomical knowledge is critical for minimizing brain exposure and avoiding surgical complications.

Comparison of clinical application of surgical approaches to the third ventricle

Objective To compare the application effect of several approaches to the third ventricle,and explore the optimal approach to resect the tumors located at the third ventricle. Methods Under the operative microscope thirty- five patients (prophase group) with the third ventricle tumors were operated via transcortical approach, trans - lamina terminalis approach or infratentorial supracerebellar approach, and twenty- one patients (anaphase group ) via transcallosal - interforniceal approach. Operative effect was observed and compared. Results Among the prophase group, the tumors were totally removed in 16 cases,subtotally in 6 cases and partially in 13 cases. Among the anaphase group, the total removal of tumor were obtained in 11 cases, subtotal in 8 cases and partial in 2 cases. Rate of total and subtotal tumor removal had significant difference between two groups. Rate of postoperative complications in anaphase group was lower than that in prophase group. Conclusion Transcallosal - interforniceal approach should be considered for treatment of tumors involving the middle and posterior portion of the third ventricle by providing a quite large operative field ,direct corridor, easier tumor resection and rare postoperative complication. Key words: Third ventricle; Transcallosal -interforniceal approach; Trans -lamina terminalis approach; Infratentorial supracerebellar approach