Oligodendroglioma of the lateral ventricle--report of 2 cases and a review

Oligodendrogliomas rarely grow primarily in the ventricles. When compared to more common hemispheric counterparts, such intraventricular oligodendrogliomas, or oligodendrogliomas of the midline group (Martin), present distinct clinical features, namely, (1) they occur in the younger age, (2) an interval between clinical onset and diagnosis or operation is shorter, and (3) initial symptoms are most often limited to those of increased intracranial pressure, although the patient may occasionally present mild organic dementia, callosal disconnection syndrome, and/or mild gait ataxia. Two cases of oligodendroglioma primarily involving the lateral ventricle are reported in female patients, aged 29 and 19, respectively, with sole complaints of an increased intracranial pressure. Magnetic resonance imaging proved to be most useful as a radiologic diagnostic procedure. The tumor was radically removed via a para-falcine transcallosal approach without causing any persistent neurological deficits. Merit and demerit of the approach are briefly discussed.     

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.     

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.     

Small callosal fenestration: anatomical and clinical study

BACKGROUND: Traditional callosotomy is associated with neurologic deficits due to surgical damage of corpus callosum and nearby brain structures. To reduce this damage, we studied a small callosal fenestration in cadaver heads and clinical patients. METHODS: Fifteen cadaver heads were used to study the anatomy of corpus callosum and nearby brain structures. Based on anatomical study, small callosal fenestration was first tested in 5 cadaver heads and then applied to 7 consecutive clinical patients. RESULTS: In cadaver heads, a 1.5 x 1.5-cm (length x width) small callosal fenestration could provide adequate surgical exposure required for most transcallosal operations. In patients, a 1.0 to 1.5 x 1.0 to 1.7-cm small callosal fenestration provided better surgical exposure than those provided by 2.5 to 3.5 cm of traditional callosotomies in our experience. During 6 months of follow-up, no obvious neurologic deficits related to surgical damage were observed in our patients who underwent small callosotomy. CONCLUSION: Small callosal fenestration is a promising alternative to traditional callosotomy in neurosurgery, which requires further investigation.     

Anterior lateral ventricular subependymal giant cell astrocytomas

Summary The surgical managagement of two cases of lateral ventricular subependymal giant cell astrocytoma, arising in the head of the Caudate nucleus, and causing hydrocephalus due to obstruction of the foramen of Monro is described. One lesion, in a patient with tuberous sclerosis, was resected using a transcallosal approach and the other, in a patient with no stigmata of tuberous sclerosis, using a frontal, trans-cortical transcystoventricular approach. The microsurgical aspects of excision and pathological anatomy of both tumours were very similar. Following tumour excision and pellucidotomy both patients had partial resolution of their hydrocephalus with complete resolution of their preoperative symptoms. The merits of transcallosal and transcortical approaches to these lesions are discussed.     

Central neurocytoma: histopathological variants and therapeutic approaches.

The central neurocytoma has recently been added to the differential diagnosis of intraventricular tumors. Histopathologically, this tumor is characterized by a uniform neoplastic cell population with features of neuronal differentiation. Central neurocytomas occur in young adults, develop in the area of the foramen of Monro, and are usually associated with the septum pellucidum. Initial reports appeared to indicate that these tumors are benign lesions with a favorable postoperative prognosis. The authors present clinical and neuropathological findings in a series of eight patients with central neurocytoma. An anterior transcallosal microneurosurgical approach yielded good outcomes. Postoperative radiation therapy was restricted to two patients with a malignant variant of central neurocytoma and one patient with a recurrent tumor. Observations of anaplastic variants of this neoplasm in two cases and local tumor recurrences in three indicate that the biological behavior and postoperative prognosis of central neurocytoma may not always be as favorable as previously assumed.     

Anterior callosal section is useful for the removal of large tumors invading the dorsal part of the anterior third ventricle: operative technique and results

Large tumors invading the dorsal part of the anterior third ventricle are difficult to manage. The anterior transcallosal approach is usually used to manage these tumors. In our clinic, anterior callosal section was combined with the anterior interhemispheric (AIH) translamina terminalis approach for these tumors with excellent results. The AIH approach is useful for removing tumors in and around the anterior part of the third ventricle. However, AIH alone is insufficient for large tumors invading the dorsal part of the anterior third ventricle. In such situations, simple anterior callosal section enables the neurosurgeon to extirpate the caudal part of the tumors deeply hidden from operative field, sparing the foramen of Monro, fornix, etc. We treated four large tumors (malignant teratoma, recurrent chordoid glioma, recurrent papillary tumor of pineal region occupying the third ventricle, and paraventricular meningioma) without major complications. The malignant teratoma case exhibited no recurrence with >10 years follow-up. The chordoid glioma and papillary tumor of pineal region were totally removed. The meningioma was subtotally removed except only a small tumor around the bilateral anterior cerebral artery. This simple technique is a new way to manage difficult large lesions in and around the third ventricle.     

Pre-coronal, paramedian minicraniotomy: a minimal access approach for microsurgical, transcallosal, transforaminal removal of colloid cysts of the third ventricle

OBJECTIVE: Microsurgical excision of colloid cysts of the third ventricle is accomplished along the transcallosal or the transfrontal routes. In the transcallosal approach, venous tributaries of the superior sagittal sinus can often act as an impediment to entry into the interhemispheric fissure for accessing the corpus callosum. We propose a paramedian minicraniotomy anterior to the coronal suture for removing colloid cysts via the transcallosal approach as veins are relatively rare in this area. METHODS: A triangular minicraniotomy was designed with each side measuring 3 cm based on the midline in the pre-coronal area of the frontal bone on the right side. Nineteen cases of symptomatic colloid cysts of the third ventricle whose diagnoses were proven by CT and/or MRI were subjected to microsurgery in the period from June 2004 to May 2007. Following the minicraniotomy the cysts were removed utilizing the transcallosal transforaminal route. RESULTS: Venous tributaries crossing the interhemispheric fissure were seen in 2 patients and these could be avoided to access the corpus callosum. Complete excision could be achieved in all cases. All patients had a good outcome although one patient had transient left lower limb weakness. The mean operating time was 163 minutes, while the mean duration of stay in the intensive care unit and hospitalization were 1.35 days and 3.73 days, respectively. CONCLUSION: The pre-coronal, paramedian minicraniotomy is safe and effective for the total excision of colloid cysts of the third ventricle. As a minimal access approach, it needs only a short duration of postoperative hospitalized care.     

Arteriovenous malformations of the lateral ventricle

Nine cases with arteriovenous malformations (AVM's) predominantly involving the lateral ventricle are presented. All the AVM's were small, but caused intraventricular hemorrhage in eight cases. Only two patients had an intracerebral hemorrhage large enough to warrant evacuation. Eight patients were under the age of 40 years at the onset of their disease. Computerized tomography demonstrated intraventricular hemorrhage in eight patients, and after intravenous administration of contrast medium a small area of enhancement with dilated subependymal draining veins was seen in seven. The lateral ventricles were of normal size in seven cases, and only two patients required a shunting procedure. Angiography demonstrated that the lesion was an AVM in eight patients, and did not visualize the lesion in the ninth. One patient suffered a recurrent intraventricular hemorrhage when the AVM was demonstrated, although repeated angiography had failed to disclose a vascular lesion at his first intraventricular hemorrhage 14 months before. All nine lesions were resected by microsurgical techniques, and the results were excellent in eight patients. Of four caudate lesions, three were resected through a frontal transcortical approach and the other was operated on through an anterior transcallosal approach; the results were excellent in three of these patients. Only one (Case 4) was left with neurological deficits; he had confusion and disorientation following a right frontal transcortical approach. Even in the dominant hemisphere, lesions in the head of the caudate nucleus could be safely resected by an anterior transcallosal approach. Two choroidal lesions located in the temporal horn and trigone on the dominant side were resected through a middle temporal gyrus approach, and three thalamic lesions through a posterior transcallosal approach, all with excellent results. In all cases the brain opening required was about the width of the retractor (maximum 2.0 cm, average 1.5 cm).     

透明隔囊肿的神经内镜手术治疗

目的探讨有症状的透明隔囊肿的神经内镜手术治疗方法及应用价值.方法采用德国产Storz外径4.0mm神经内镜经纵裂入路及经额角入路行囊肿-侧脑室造瘘术治疗有症状的透明隔囊肿12例,头痛、癫痫及精神症状为主要临床表现,其中2例合并脑积水.结果12例术后症状均改善,其中以颅高压症为主要表现者6例中,4例症状完全消失,2例减轻,4例癫痫发作者未再发作.12例随访6个月～2年,平均18个月,复查CT或MRI囊肿缩小＜50%7例,50%～90%3例,＞90%2例.2例脑积水均消失.结论对透明隔囊肿应用神经内镜行囊肿-侧脑室造瘘术微创、安全、有效.     

Lesions of the corpus callosum in hydrocephalic patients with ventricular drainage — a CT-study

Summary Patients with ventricular drainage may develop lesions of the corpus callosum. In order to study frequency, pathogenesis and clinical relevance of callosal lesions, 301 routine CT investigations of 79 patients with ventricular drainage were reviewed. Hypodense lesions in the anterior part of the corpus callosum were observed in 7 patients with longstanding hydrocephalus of variable origin, in 2 cases the corpus callosum was slightly swollen. All 7 patients showed signs of forced ventricular drainage. The callosal alterations were clinically inapparent and potentially reversible. Knowledge of these lesions is important to avoid misinterpretation.     

Evoked Potentials in Acute Head Injured Patients with MRI-Detected Intracerebral Lesions

Summary. Summary. Background: Magnetic resonance imaging (MRI) allows precise detection of intracranial lesions in head injured patients. We compared intracranial lesions detected in MRI to somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) concerning their prognostic value. Methods: Thirty patients with traumatic brain injury and prolonged recovery were studied. Size, side and number of 474 intra- and extraparenchymal lesions as well as lesion localisation based on a specific anatomical classification were entered into a database (a total of 7080 data). In addition, we recorded median-nerve SEP (M-SEP), tibial nerve SEP (T-SEP) and BAEP in all of the patients. Findings M-SEP and Glasgow-Outcome-Score (GOS) one year after injury correlated significantly to patients with lesions in the brainstem (p<0.0001) and corpus callosum (p<0.001). Similar results were found for T-SEP (p<0.0001). All patients with bicortical loss of M-SEP had an unfavourable outcome (GOS 2). Among the analysis of lesion volume, only the volume of brainstem lesions correlated to GOS (p<0.001), but this was not found for callosal lesions. However, comparing the vegetative (GOS 2) to the non-vegetative group (GOS 3–5), for both callosal (p<0.02) and brainstem (p<0.005) lesions a significant correlation was found. Interpretation: MRI does not improve the prognostic reliability of SEP in head injury but offers possibilities for clarifying electrophysiological and clinical pathologies. This explains that the volume of brainstem lesions, essentially influencing the clinical outcome, is strongly correlated to T-SEP and M-SEP. In contrast, callosal lesions did not show a clear relationship to outcome despite large callosal lesions (>4 ml) which tended to poor outcome. In conclusion, we suggest that MRI and SEP are supplementary to each other concerning prognostic evaluation.     

Posterior midline approach for large anterior/anterolateral foramen magnum tumours

The standard surgical approaches described for excision of anterior or anterolaterally placed foramen magnum (FM) tumours are the far lateral approach, the extreme lateral approach and the transoral approach. In general the posterior midline approach is considered not suitable for these lesions. We have operated on 27 patients with benign anterior/anterolaterally placed FM tumours in the last 8 years. Thirteen of these were operated via the posterior midline approach. All these 13 patients had large or giant tumours displacing the cervicomedullary region posteriorly and laterally. This allowed adequate access through this approach with minimal handling of neural tissue. For small lesions, the far lateral approach was used. Most of the patients improved significantly neurologically. We recommend the standard midline posterior approach for large/giant FM tumours as the tumour size itself provides enough working space for the surgeon. For small lesions, the far lateral approach is preferred.     

Massive traumatic haematoma of the corpus callosum

Summary Five unusual cases with massive haematoma of the corpus callosum caused by blunt head trauma are presented. Aside from the callosal haematomas, intraventricular and subarachnoid haemorrhages or small haemorrhagic foci in the basal ganglia or thalamus were common concomitant lesions on the computerized tomographic (CT) scan. The sites of the impacts were the frontal and occipital areas which were close to the midline and above the level of the corpus callosum. Severe and diffuse brain dysfunction was suggested by the severity of the Glasgow coma score (GCS) and the abnormality on multimodality evoked potentials. An intensive medical treatment such as barbiturate could be promising since a direct surgical approach was dubious because of additional damage to the severely injured brain.     

Microsurgical management of lateral ventricular meningiomas: a report of 51 cases

BACKGROUND: Lateral ventricular meningiomas are notably rare and the optimal surgical management for them remains a challenge. We made a retrospective study of patients with these lesions and analyzed the clinical findings, radiological features and especially the surgical treatment on the basis of surgical approaches and techniques. MATERIALS AND METHODS:A total of 51 patients with lateral ventricular meningiomas were operated on between 1996 and 2006 in our institution. The mean patient age was 44 years (range: 14-75 years). The most common presenting symptoms were related to the gradually increasing high cranial pressure (82.4%) rather than the location of the tumor. The transcortical parieto-occipital approach was used in 38 patients, the temporal approach was used in 9 patients and the transcallosal approach was used in 4 patients. RESULTS: The total surgical excision was complete in 48 patients (94.1%), and 3 patients with subtotal excision received radiotherapy after the operation. The previous visual fields deficits in two patients worsened and a new visual disturbance or sensory aphasia appeared in two patients. One patient died of postoperative hypothalamus complications. Thirty-eight patients underwent follow-up (range: 6 months-10 years). The conditions of 35 of these were excellent or good. No recurrence has been seen in any patient. CONCLUSIONS: Understanding the features of lateral ventricular meningiomas will help one to select an appropriate surgical approach. An individualized approach is needed, and the transcortical parieto-occipital approach or transtemporal approach is advantageous for most cases in our opinion. Also, it is possible to achieve a good surgical outcome with little neurological morbidity if we take wise strategies and techniques during excision.     

The Transcallosal Anterior Interfoniceal Approach: A Microsurgical Anatomy Study

Objectives A plethora of surgical strategies have been described to reach deep-seated lesions situated within the third ventricle including the Rosenfeld, or transcallosal anterior interfoniceal (TAIF), approach. First introduced in 2001, it consists of a small callosotomy followed by the midline transseptal dissection of fornices to enter the roof of the third ventricle. The aim of this microsurgical anatomy study is to describe and show each stage of the surgical procedure, focusing on the possible trajectories to anatomical landmarks. Participants A total of 20 adult cadaveric specimens were used in this study. Using ×3 to ×40 magnifications, the surgical dissection was performed in a stepwise fashion, and the transcallosal anterior interforniceal approach was performed, analyzed, and described. Results In 5 specimens of 10, a cavum septum pellucidum was depicted. In 5 cases of 20 after the callosotomy ,the lateral ventricular cavities were reached. Different orientation of the microscope allowed us to define three surgical trajectories to visualize the region of interest without exposing important functional areas. Conclusion The TAIF represents a minimally invasive approach to the third ventricle; its tricky surgical steps make appropriate anatomical dissection training essential to become confident and skilled in performing this approach.     

Treatment of colloid cysts of the third ventricle by stereotaxic microsurgical laser craniotomy

The therapeutic strategies employed in the management of anterior third-ventricular mass lesions remain controversial. Resection by conventional craniotomy, whether via a transcallosal or transcortical approach, carries well-known risks and limitations. Alternatively, in this region traditional stereotaxy has been relegated to use with biopsy only or cyst aspiration procedures. Combining aspects of both conventional and stereotaxic techniques has allowed total removal of 12 colloid cysts in six women and six men ranging in age from 25 to 71 years. No mortality and minimal morbidity have been associated with the procedures. There has been no evidence of recurrence in an average follow-up period of 19 months. By coupling the benefits of stereotaxic precision and localization to the microsurgical management of colloid cysts, several rewards have been realized: 1) only a limited cortical dissection is needed; 2) the hazards of callosal or forniceal injury can be avoided; 3) the lesion is easily localized regardless of ventricular size; 4) hemostasis can be readily achieved with bipolar cautery or defocused laser power; and 5) most importantly, a total resection is possible with little risk to the patient. Stereotaxic microsurgical laser craniotomy provides a new option for the management of colloid cysts and other anterior third-ventricular lesions.     

James IV Lecture. Epilepsy surgery,hypothalamic hamartomas and the quest for a cure

This presentation reviews the epidemiology of epilepsy, the evolution of epilepsy surgery, the selection of cases for surgery, the range and results of epilepsy surgery, and the future development of this burgeoning field. Hypothalamic hamartoma (HH) is a rare developmental lesion which causes intractable gelastic epilepsy which is refractory to medical therapy. Hypothalamic hamartoma presents a formidable surgical challenge. The application of a midline transcallosal interforniceal approach to resect the HH from within the third ventricle, in a series of 28 patients, is presented. This has produced excellent results with minimal morbidity. This surgery is placed within the context of epilepsy surgery in general.     

Surgery of tumours of the lateral ventricle

Summary Tumours of the lateral ventricle in most cases enlarge significantly before signs and symptoms are exhibited.In the years between 1980 and 1991 we encountered 55 patients of all age groups with tumours of the lateral ventricle. All were diagnosed either by CT or MRI, and in lesions with good enhancement on CT additional angiography was performed. All 55 tumours were operated upon using microsurgical techniques. The approach was chosen according to the location of the tumour, preferably transcortical. In selected cases large tumours were removed in a twostage operation. Only in one frontal horn and Cella media tumour an interhemispheric transcallosal approach was used. Postoperative or surgically related mortality was experienced in 3 cases. Life expectancy and morbidity were dependent upon histology.Invited Lecture presented at the European Congress, Moscow, June 23–29, 1991.