Lateral Ventricle Tumors: Surgical Strategies According to Tumor Origin and Development— A Series of 72 Cases

Intraventricular Tumors: Surgical Considerations in Lateral and Third Ventricular Tumors

Management of lateral and third ventricular tumors has been a challenge for neurosurgeons. Advances in imaging and pathology have helped in a better understanding of the treatment options. Technical refinement of microsurgical technique and addition of endoscopy has enabled more radical excision of tumors, when indicated, and added more safety.A proper understanding of the pathology at various ages and treatment options is continuously evolving. Many pediatric tumors are amenable to conservative surgical methods with effective complementary treatments. However, radical surgery is required in many adults as the main treatment and for many benign tumors. Various intraventricular lesions encountered and their surgical management is reviewed here for their efficacy, safety, and outcome, encompassing changes in our practice over the last 20 years.

Application of endoport-assisted neuroendoscopic techniques in lateral ventricular tumor surgery

Objective

The objective of this study was to investigate the clinical experience and therapeutic efficiency of Endoport-assisted neuroendoscopic surgery for resection of lateral ventricular tumors. The key points and application value of this surgical technique were additionally discussed.

Methods

A retrospective analysis was conducted on the clinical and follow-up data of 16 patients who underwent endoport-assisted neuroendoscopic surgery for lateral ventricular tumors at the Department of Neurosurgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, between January 2018 and September 2020. The surgical procedures, complications and outcomes were analyzed.

Results

The study included a total of 16 patients (5 males and 11 females) with lateral ventricular tumors, with a mean age of 43.2 years (18-70 years old). The tumors were distributed as follows: 5 cases involved the body of the lateral ventricle, 3 involved the frontal horn and body, 3 involved the occipital horn, 2 involved the trigone, 2 involved the frontal horn, and 1 case involved the occipital horn and body. Perioperative complications were analyzed, revealing 1 case of intraoperative acute epidural hematoma intraoperative and 2 cases of postoperative obstructive hydrocephalus. All complications were promptly managed. Postoperative MRI revealed that 14 cases (88%) achieved total resection, while 2 cases (12%) achieved subtotal resection. During the follow-up of 6-38 months, no recurrence was observed. The patient diagnosed with glioblastoma died 16 months after surgery (GOS=1), while the remaining patients have successfully resumed to normal daily life with a GOS score of 5.

Conclusion

In conclusion, endoport-assisted neuroendoscopic surgery proved to be a minimally invasive and effective technique for resecting lateral ventricular tumors, with acceptable complications. It effectively utilizes the benefits of close observation, comprehensive exposure, and reduced tissue damage. Therefore, endoport-assisted neuroendoscopic surgery is suitable for the resection of lateral ventricular tumors.

Trigone ventricular glioblastoma multiforme with trapped temporal horn: A case report

Background

Intraventricular glioblastoma multiforme (GBM) is extremely rare, especially in the trigone region. This report presents a case of trigone ventricular GBM with trapped temporal horn (TTH).

Case presentation

A 59-year-old woman was admitted to our department with a 1-month history of rapidly progressive headache, nausea, and weakness in the right lower extremity. Head non-contrast computed tomography and enhanced magnetic resonance imaging (MRI) revealed a trigone ventricular mass lesion with TTH and heterogeneous enhancement. The lesion was found 18 months ago as a small asymptomatic tumor mimicking ependymoma. This neoplasm was removed subtotally through the right parieto-occipital approach guided by neuroendoscopy. A ventriculoperitoneal shunt was subsequently performed to relieve TTH. The final pathological diagnosis was GBM. Unfortunately, 36 days after the first surgery, the patient died due to her family’s decision to refuse therapy.

Conclusion

This rare case shows that GBM should be considered in the differential diagnosis of trigonal tumors. In this case, the tumor possibly originated from the neural stem cells in the subventricular zone. Patients with intraventricular GBM have a worse prognosis, and careful follow-up and early surgery for small intraventricular tumors are necessary, even for those with ependymoma-like radiological findings.

Impact of Adjuvant Radiotherapy in Patients with Central Neurocytoma: A Multicentric International Analysis

Simple Summary

Central neurocytoma is a rare tumor accounting for <0.5% of all intracranial tumors. We analyzed 33 patients treated with surgical resection with or without radiotherapy from ten closely cooperating institutions in Germany, Egypt, and Jordan. Patients who received radiotherapy had longer progression-free survival with an acceptable toxicity profile.

Abstract

Background: Central neurocytoma (CN) is a rare tumor accounting for <0.5% of all intracranial tumors. Surgery ± radiotherapy is the mainstay treatment. This international multicentric study aims to evaluate the outcomes of CNs patients after multimodal therapies and identify predictive factors. Patients and methods: We retrospectively identified 33 patients with CN treated between 2005 and 2019. Treatment characteristics and outcomes were assessed. Results: All patients with CN underwent surgical resection. Radiotherapy was delivered in 19 patients. The median radiation dose was 54 Gy (range, 50–60 Gy). The median follow-up time was 56 months. The 5-year OS and 5-year PFS were 90% and 76%, respectively. Patients who received radiotherapy had a significantly longer PFS than patients without RT (p = 0.004) and a trend towards longer OS. In addition, complete response after treatments was associated with longer PFS (p = 0.07). Conclusions: Using RT seems to be associated with longer survival rates with an acceptable toxicity profile.

Maximal surgical resection and adjuvant surgical technique to prolong the survival of adult patients with thalamic glioblastoma

The importance of maximal resection in the treatment of glioblastoma (GBM) has been reported in many studies, but maximal resection of thalamic GBM is rarely attempted due to high rate of morbidity and mortality. The purpose of this study was to investigate the role of surgical resection in adult thalamic glioblastoma (GBM) treatment and to identify the surgical technique of maximal safety resection. In case of suspected thalamic GBM, surgical resection is the treatment of choice in our hospital. Biopsy was considered when there was ventricle wall enhancement or multiple enhancement lesion in a distant location. Navigation magnetic resonance imaging, diffuse tensor tractography imaging, tailed bullets, and intraoperative computed tomography and neurophysiologic monitoring (transcranial motor evoked potential and direct subcortical stimulation) were used in all surgical resection cases. The surgical approach was selected on the basis of the location of the tumor epicenter and the adjacent corticospinal tract. Among the 42 patients, 19 and 23 patients underwent surgical resection and biopsy, respectively, according to treatment strategy criteria. As a result, the surgical resection group exhibited a good response with overall survival (OS) (median: 676 days, p < 0.001) and progression-free survival (PFS) (median: 328 days, p < 0.001) compared with each biopsy groups (doctor selecting biopsy group, median OS: 240 days and median PFS: 134 days; patient selecting biopsy group, median OS: 212 days and median PFS: 118 days). The surgical resection groups displayed a better prognosis compared to that of the biopsy groups for both the O6-methylguanine-DNA methyltransferase unmethylated (log-rank p = 0.0035) or methylated groups (log-rank p = 0.021). Surgical resection was significantly associated with better prognosis (hazard ratio: 0.214, p = 0.006). In case of thalamic GBM without ventricle wall-enhancing lesion or multiple lesions, maximal surgical resection above 80% showed good clinical outcomes with prolonged the overall survival compared to biopsy. It is helpful to use adjuvant surgical techniques of checking intraoperative changes and select the appropriate surgical approach for reducing the surgical morbidity.

Minimizing cortical disturbance to access ventricular subependymoma - A novel approach utilizing spinal minimally invasive tubular retractor system

Background:

Subependymomas are rare benign tumors found primarily in the lateral and fourth ventricles. Patients become symptomatic when the tumor obstructs cerebrospinal fluid pathways. We present a novel minimally invasive technique for lateral ventricular subependymoma resection.

Case Description:

A 57-year-old male presented after a period of progressive ataxia, right upper extremity tremor, and syncopal events. Emergent non-contrast computed tomography of the brain demonstrated a lobulated mass in the left lateral ventricle causing moderate-to-severe obstructive hydrocephalus. Emergent ventriculostomy was placed as a temporizing measure. Subsequent magnetic resonance imaging (MRI) illustrated a large benign appearing mass causing obstruction of the left foramen of Monroe. A small craniotomy was performed utilizing previous ventriculostomy twist hole. The left lateral ventricle was accessed through sequential dilation of ventriculostomy tract using a minimally invasive spine surgery tubular system. Tumor was resected en bloc under microscopic assistance. The patient had an excellent outcome with return to baseline mental status and was discharged from the hospital postoperative day 1. Follow-up MRI demonstrated gross total resection of the mass and decreasing lateral ventricle hydrocephalus with minimal cortical disturbance.

Conclusion:

A minimally invasive tubular system approach to ventricular tumors can be utilized to minimize cortical resection and brain retraction. Minimally invasive surgery also has the potential to decrease the length of stay and enhance postoperative recovery.

Endoscopic resection of the third ventricular epidermoid cysts: A case review and review of literature

Background

Epidermoid cysts are benign, congenital lesions that originate from ectodermal cells, they are most commonly found in the cerebellopontine angle, but rarely in the ventricular system. There is limited literature regarding the different microsurgical techniques utilized to approach these lesions.

Methods

A 63-year-old female with a recurrent third ventricular epidermoid cyst underwent gross total resection utilizing an endoscopic technique. We also reviewed the various endoscopic/microsurgical approaches and outcomes reported in literature.

Results

We identified 15 cases, including our own. Nine of these were managed using microsurgical techniques, while six cases (including ours) were treated endoscopically; gross total resection was achieved in 10/15 cases (67%). Most commonly, surgeons utilized the interhemispheric transcallosal approach (five cases). Tumor recurrence was seen in two cases. Complications attributed to these resections included: disorders of the hypothalamic-pituitary axis (3) - diabetes insipidus, galactorrhea, and hypopituitarism; tumor recurrence (2); aseptic meningitis (1); and a transient Korsakoff syndrome (1).

Conclusion

Epidermoid cysts of the third ventricle are exceedingly rare, and surgical resection is generally well tolerated. Microsurgical transcortical, transcallosal, and endoscopic approaches each have advantages and disadvantages, and are associated with unique procedure-specific complications. Continuing technological improvement would favor endoscopic approaches for resection of tumors of the third ventricle in the future.

Tumors of the lateral and third ventricle: surgical management and outcome analysis in 42 cases

Objectives:

To discuss the clinical presentation, pathological diagnosis, and surgical outcome for a series of 42 consecutive patients treated for lateral and third ventricular tumors.

Methods:

This is a retrospective series study conducted between 2001 and 2015 and included 42 patients (mean age: 25 years; range: 2 months-65 years) with lateral and third ventricle tumors surgically treated at King Khaled University Hospital, Riyadh, Kingdom of Saudi Arabia. Demographic, clinical, radiological, surgical, histopathological, and follow up data were analyzed.

Results:

The most common symptoms at presentation included headache (69%), nausea/vomiting (38%), visual deficits (24%), and seizures (17%). Lesions were located in the lateral ventricle in 15 patients, third ventricle in 20 patients, and involved both the lateral and third ventricles in 7 patients. The most common tumor types in the overall cohort were colloid cysts (n=6) and pineal tumors (n=6). The postoperative complication rate was 36%. The most common postoperative complications were seizure and hydrocephalus (n=5 each, 12%). Surgical mortality was 5%.

Conclusion:

The selection of the surgical approach for intraventricular tumor resection is fundamentally dependent on the surgeon’s experience and preference. We recommend that this decision be based on the anatomic considerations that provide the best and safest access to the mass, rather than on the risk of seizure following transcortical approach.

Tumor Volume Decrease via Feeder Occlusion for Treating a Large, Firm Trigone Meningioma

Trigone meningiomas are considered a surgical challenge, as they tend to be considerably large and hypervascularized at the time of presentation. We experienced a case of a large and very hard trigone meningioma that was effectively treated using initial microsurgical feeder occlusion followed by surgery in stages. A 19-year-old woman who presented with loss of consciousness was referred to our hospital for surgical treatment of a brain tumor. Radiological findings were compatible with a left ventricular trigone meningioma extending laterally in proximity to the Sylvian fissure. At initial surgery using the transsylvian approach, main feeders originating from the anterior and lateral posterior choroidal arteries were occluded at the inferior horn; however, only a small section of the tumor could initially be removed because of its firmness. Over time, feeder occlusion resulted in tumor necrosis and a 20% decrease in its diameter; the mass effect was alleviated within 1 year. The residual meningioma was then totally excised in staged surgical procedures after resection became more feasible owing to ischemia-induced partial softening of the tumor. When a trigone meningioma is large and very hard, initial microsurgical feeder occlusion in the inferior horn can be a safe and effective option, and can lead to necrosis, volume decrease, and partial softening of the residual tumor to allow for its staged surgical excision.

Paraventricular meningioma revealed by mental disorder

BACKGROUND

Ventricular meningioma constitutes 2% of intracranial meningioma, representing a challenging disease for neurosurgeons. Although cognitive impairment is one of the major symptoms of ventricular tumors, few studies have reported the details of cognitive impairment before and after their surgical removal. The expected effects on cognitive function should also be considered when choosing a surgical approach.

CASE DESCRIPTIONS

We report the case of a large lateral ventricle meningioma revealed by cognitive dysfunction and moderate intellectual disability. The patient underwent subtotal resection of the tumor which had partial improvement in cognitive disorders. It is important to precisely assess neuropsychological function in patients with large brain tumors, and judicious preoperative plan, adequate knowledge of anatomy, and use of correct microsurgical techniques are fundamental in achieving complete resection of paraventricular meningioma with low morbidity.

CONCLUSION

Pre and postoperative precise neuropsychological examinations may identify the potential cognitive impairment and beneficial effects of surgery in patients with large lateral ventricle meningiomas.

Microsurgical resection of tumors of the lateral and third ventricles: operative corridors for difficult-to-reach lesions

Tumors of the lateral and third ventricles are cradled on all sides by vital vascular and eloquent neural structures. Microsurgical resection, which always requires attentive planning, plays a critical role in the contemporary management of these lesions. This article provides an overview of the open microsurgical approaches to the region highlighting key clinical perspectives.

The Pterional-Transsylvian Approach for Tumor in the Temporal Horn: A Case Report

A variety of surgical approaches to temporal horn tumors of the lateral ventricle have been described. Magnetic resonance imaging (MRI) and angiography are the preferred modalities for preoperative evaluation and provide important information for the choice of surgical approach. A 59-year-old man was referred to our hospital due to confusion and gait disturbance. On enhanced MRI, a homogeneous enhanced solitary mass was observed within the temporal horn of the left lateral ventricle with transependymal extension. The lesion was accompanied by increased hypervascular tumor blush on preoperative cerebral angiography. Subtotal removal of the temporal horn tumor was performed because the lesion was identified as lymphoma during surgery. The postoperative course was un-eventful. The patient was referred to the oncology department for conventional chemotherapy. Adjuvant chemotherapy improved the clinical outcome. The pterional-transsylvian approach was beneficial for partial removal of the tumor and tissue diagnosis in this case.

The cerebral isthmus: fiber tract anatomy, functional significance, and surgical considerations

OBJECTIVE

The cerebral isthmus is the white matter area located between the periinsular sulcus and the lateral ventricle. Studies demonstrating the fiber tract and topographic anatomy of this entity are lacking in current neurosurgical literature. Hence, the authors' primary aim was to describe the microsurgical white matter anatomy of the cerebral isthmus by using the fiber dissection technique, and they discuss its functional significance. In addition, they sought to investigate its possible surgical utility in approaching lesions located in or adjacent to the lateral ventricle.

METHODS

This study was divided into 2 parts and included 30 formalin-fixed cerebral hemispheres, 5 of which were injected with colored silicone. In the first part, 15 uncolored specimens underwent the Klinger's procedure and were dissected in a lateromedial direction at the level of the superior, inferior, and anterior isthmuses, and 10 were used for coronal and axial cuts. In the second part, the injected specimens were used to investigate the surgical significance of the superior isthmus in accessing the frontal horn of the lateral ventricle.

RESULTS

The microsurgical anatomy of the anterior, superior, and inferior cerebral isthmuses was carefully studied and recorded both in terms of topographic and fiber tract anatomy. In addition, the potential role of the proximal part of the superior isthmus as an alternative safe surgical corridor to the anterior part of the lateral ventricle was investigated.

CONCLUSIONS

Using the fiber dissection technique along with coronal and axial cuts in cadaveric brain specimens remains a cornerstone in the acquisition of thorough anatomical knowledge of narrow white matter areas such as the cerebral isthmus. The surgical significance of the superior isthmus in approaching the frontal horn of the lateral ventricle is stressed, but further studies must be carried out to elucidate its role in ventricular surgery.

The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

OBJECT

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

METHODS

The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author's surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6.

RESULTS

Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0-2) and 6 (13%) had poor outcome (mRS scores 3-4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

CONCLUSIONS

The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors' experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach fora specific region.

Infarction of the lateral posterior choroidal artery territory after manipulation of the choroid plexus at the atrium: causal association with subependymal artery injury

OBJECT

The atrium of the lateral ventricle is often affected by tumors, and some patients with these tumors suffer neurological deficits, including hemiparesis after surgery. The authors of this study investigated the possible mechanisms causing the relatively high incidences of ischemic complications associated with surgery approaching the atrium of the lateral ventricle.

METHODS

Clinical records and radiological images of 28 patients were retrospectively studied. These patients had their lateral ventricles opened at the atrium during the resection of gliomas as well as other nonbenign brain tumors, and were treated for gliomas at our tertiary referral center in the Tohoku district, Japan, between January 2008 and December 2010.

RESULTS

Routine postoperative diffusion-weighted MR images obtained within 72 hours after surgery detected infarction in the periatrial/periventricular regions in 7 patients, presumably corresponding to the lateral posterior choroidal artery (LPChA) territory. Five of these 7 patients suffered neurological sequelae with varying severities. The choroid plexus at the atrium was coagulated to achieve hemostasis during the surgery in all of these patients. Detailed analysis of microangiograms revealed ventriculofugal arteries arising from the lateral ventricle. Damage of the subependymal artery that supplies the ventriculofugal arteries caused by coagulation of the choroid plexus at the atrium probably resulted in the infarction in these patients.

CONCLUSIONS

Neurosurgeons must be aware of the possibility of LPChA territory infarction during surgery in the atrial or periatrial regions caused by subependymal artery obstruction after manipulating or coagulating the choroid plexus near the atrium.

Surgical management of thalamic gliomas: case selection, technical considerations, and review of literature

This study aimed to identify (1) the thalamic gliomas suitable for surgical resection and (2) the appropriate surgical approach based on their location and the displacement of the posterior limb of the internal capsule (PLIC). A retrospective study over a 5-year period (from 2006 to 2010) was performed in 41 patients with thalamic gliomas. The mean age of these patients was 20.4 years (range, 2-65 years). Twenty (49 %) tumors were thalamic, 19 (46 %) were thalamopeduncular, and 2 (5 %) were bilateral. The PLIC, based on T2-weighted magnetic resonance axial sections, was displaced anterolaterally in 23 (56 %) cases and laterally in 6 (14 %) cases. It was involved by lesion in eight (20 %) cases and could not be identified in four (10 %) cases. Resection, favored in patients with well-defined, contrast-enhancing lesions, was performed in 34 (83 %) cases, while a biopsy was resorted to in 7 (17 %) cases. A gross total resection or near total resection (>90 %) could be achieved in 26 (63 %) cases. The middle temporal gyrus approach, used when the PLIC was displaced anterolaterally, was the commonly used approach (63.5 %). Common pathologies were pilocytic astrocytoma (58 %) in children and grade III/IV astrocytomas (86 %) in adults. Preoperative motor deficits improved in 64 % of the patients with pilocytic lesions as compared to 0 % in patients with grade III/IV lesions (P value, 0.001). Postoperatively, two patients (5 %) had marginal worsening of motor power, two patients developed visual field defects, and one patient developed a third nerve paresis. Radical resection of thalamic gliomas is a useful treatment modality in a select subset of patients and is the treatment of choice for pilocytic astrocytomas. Tailoring the surgical approach, depending on the relative position of the PLIC, has an important bearing on outcome.

Frontal transcortical approach in 12 central neurocytomas

BACKGROUND

Central neurocytomas (CN) are rare intraventricular tumors with benign clinical behavior that typically affect young adults. Although a favorable prognosis is generally expected after adequate management, there is no general consensus on the standard of therapy. We evaluated the efficacy and safety of radical surgery for the management of CN.

METHODS

Between 1996 and 2010, 12 patients with CN (eight males and four females; range, 18 to 62 years; mean age, 28.5 years) were surgically treated in our institution. The initial goal of therapy was complete resection through a frontal transcortical approach, and repeat surgery was done in cases of residual or recurrent disease. The mean follow-up period was 51.2 months (range, 14-149 months).

RESULTS

Complete resection was achieved in all patients either with primary (nine patients, 75 %) or second-look surgery (three patients, 25 %). No mortalities occurred and there were four surgery-related complications (two events of transient hemiparesis, one transient aphasia, and onepostoperative subdural hygroma). All patients were alive with normal activities of daily living at the last follow-up. Two patients (16.6 %) experienced a single recurrence at 26 and 66 months, one of whom underwent redo-surgery.

CONCLUSION

For the management of CN, complete resection is feasible, effective, and safe. Repeat surgery may be a viable option in cases of residual or recurrent disease and the use of radiotherapy can be avoided in this young population.

Neuroendoscopic surgery in empty ventricular system under continuous gas infusion experimental study of pressure changes and complications

INTRODUCTION

The most important limitations to endoscopic procedures in the ventricular system of the brain are due to the constraint of working inside a fluid. The evacuation of cerebrospinal fluid (CSF) from the ventricles is performed often in microsurgical interventions using a surgical microscope. This study aimed at studying the evacuation of CSF during neuroendoscopic surgery in animals while infusing gas to avoid ventricular collapse.

MATERIALS AND METHODS

Hydrocephalus was provoked in five adult New Zealand rabbits by intracisternal injection of kaolin. Endoscopic intervention was performed later; fluid was given as a continuous infusion at constant speed into the CSF for 3 min. In the next stage, CSF was evacuated from the ventricles, which were infused with gas at a stable rate for the same amount of time. The intracranial pressure (ICP) of the rabbits was recorded during both operations. The animals were sacrificed and the brain subjected to pathology examination at the end of the experiment.

RESULTS

Mean ICP value in the rabbit ventricle was 19.1 while working in CSF and 17.6 when working in air. The difference by a paired test was statistically significant for each individual rabbit except one. The ICP measurement, however, was never lower than the ambient pressure, even while working in continuous gas infusion. No epidural or subdural hematomas were found at autopsy.

CONCLUSIONS

Endoscopic surgery is feasible in a ventricular system that has been insufflated with gas after CSF has been evacuated. During the experiment, however, steadily diminishing ICP values were measured. As a result, new devices, such as small-flow insufflators able to perform sensitive pressure adjustments are needed.

[Surgical anatomy of the lateral ventricles]

The lateral ventricle is a deep-seated cavity, overlayed by a cortical mantle which contains eloquent areas, especially on the dominant hemisphere, and surrounded by the optic radiations. The surgical approach requires a thorough preoperative reflexion based on magnetic resonance imaging, in order to understand the site of origin and the vascular pedicles of the tumor. Surgical approaches to the frontal horn, temporal horn and atrium are successively described.

Intraventricular inflammatory pseudotumor: report of two cases and review of the literature

Inflammatory pseudotumors (IP) are non-neoplastic lesions characterized by collagenous stroma and polyclonal mononuclear infiltrates. It is best characterized in the lung, but can occur in the CNS, mimicking a neoplastic process. We discuss the available literature and our cases in order to elucidate best medical practices when confronted with such a lesion. We report on two cases of intraventricular inflammatory pseudotumor in patients who presented with symptoms of CSF obstruction. Both patients were treated surgically with significant clinical improvement. Histopathologically, both specimens revealed a plasma cell granuloma variant of IP. A Medline search for English articles identified 46 cases of CNS IP, only eight of which were located within the ventricle. As with our case, most patients presented due to CSF obstruction or mass effect. Radiographically, the lesions have a variable appearance although most enhanced with gadolinium. Complete resection was achieved in 67% with a 12% rate of recurrence. With incomplete resection or biopsy alone, progression is seen despite steroid or radiation administration. Malignant transformation was only reported once. CNS IP is a rare pathological entity that cannot be diagnosed through clinical presentation or radiographic characteristics, but rather through a careful neuropathological inspection. The available literature suggests that complete resection with close follow-up is necessary.

Surgical management of lateral-ventricle metastases: report of 29 cases in a single-institution experience

OBJECT

The aim of this study was to review the outcome of patients undergoing surgery for treatment of lateral-ventricle metastases.

METHODS

Imaging information and chart reviews of operative reports were used to conduct a retrospective analysis in 29 patients who underwent resection of lateral-ventricle metastases at the authors' institution between 1993 and 2007. Clinical and neurosurgical outcomes and recurrence rates were studied.

RESULTS

The mean patient age was 56 years (range 20-69 years); 66% of patients were male. Single intraventricular metastases occurred in 69% of patients, and 55% of them had systemic metastases. The 30-day postoperative mortality rate was 7%. There was intracerebral tumor recurrence in 41% of patients, with 1 patient undergoing a second operation for this. The median postoperative survival duration for 28 patients (excluding 1 patient with preoperative leptomeningeal disease) was 11.7 months; the 3- and 5-year survival rates were 17 and 11%, respectively. Univariate analysis identified factors significantly influencing survival, including the preoperative Karnofsky Performance Scale (KPS) score (p = 0.02), the number of cerebral metastases (p = 0.02), the presence of primary renal cell carcinoma (RCC) (p = 0.02), and the resection method (en bloc vs piecemeal; p = 0.05). The presence of extracranial metastases did not significantly influence survival. Multivariate analysis showed that the preoperative KPS score (p = 0.002), the presence of primary RCC (p = 0.039), and the resection method (en bloc vs piecemeal; p = 0.008) correlated significantly with survival time.

CONCLUSIONS

Surgery is an important component in the management of intraventricular metastases. To the authors' knowledge, this is the first study focusing totally on resection of lateral-ventricle metastases. The authors found that patients with primary RCC, those with a favorable preoperative KPS score, and those who underwent en bloc resection had a better outcome than others.

Posterior interhemispheric transfalx transprecuneus approach to the atrium of the lateral ventricle: a cadaveric study

OBJECT

The posterior interhemispheric transprecuneus gyrus approach is one of the surgical routes that has been suggested to reach the atrium of the lateral ventricle. It has the advantage of avoiding the disruption of the optic radiations; however, it has a narrow working area that at times makes the execution of this approach rather challenging. The aim of this study was to test a modification of the approach that might create a better surgical angle and a wider corridor by accessing the atrium from the contralateral side after transection of the falx. The authors named this new approach the "posterior interhemispheric transfalx transprecuneus approach."

METHODS

The posterior interhemispheic transfalx transprecuneus approach was performed bilaterally on 6 fresh adult cadaveric specimens for a total of 12 procedures. Every head was held in the semisitting position and a parasagittal parietooccipital craniotomy on the contralateral side of the targeted ventricle was executed. The dura mater was opened and reflected based on the sagittal sinus. Then the falx was cut in a triangular fashion based on the inferior sagittal sinus. Using the parietooccipital artery and sulcus as landmarks, the contralateral precuneus gyrus was indentified, and a small area of the gyrus was transected to gain access to the atrium. A neuronavigational system was also used to conduct this approach. The working angle of this approach and other distances were measured.

RESULTS

The authors were able to visualize the ventricular atrium, posterior part of the temporal horn, pulvinar, and choroid plexus in all specimens. The temporal horn could be exposed for a length of 20-30 mm from the atrium. The working angle of the approach was better than that of the classic posterior interhemispheric transprecuneus approach with a mean value of 44.5° as opposed to 25.8°. The distance from the middle point of the corticotomy to the splenium ranged from 11 to 16 mm (mean 13.3 mm); the distance to the torcula, from 34 to 53 mm (mean 41.3 mm); and the distance to the atrium, from 22 to 31 mm (mean 25.7 mm).

CONCLUSIONS

Results of this study suggested that the proposed approach can expose the atrium and the posterior part of the temporal horn of the lateral ventricle with a wider surgical angle compared with the conventional homolateral posterior interhemispheric transprecuneus gyrus approach. Moreover, by minimizing the amount of brain retraction homolateral to the target, this approach could make navigation more accurate.

Preservation of visual fields with the inferior temporal gyrus approach to the atrium

Various transcortical approaches have been described for the resection of tumors that lie in the atrium of the lateral ventricle. An approach through the middle temporal gyrus has a short trajectory to the atrium and can grant early access to the tumor's blood supply, but it typically results in damage to the optic radiations that course lateral to the atrium. Anatomical studies have suggested that an approach inferior to the inferior temporal sulcus would avoid traversing through the optic radiations. The authors describe 2 cases of meningioma in the atrium that were exposed and resected through an incision in the inferior temporal gyrus. They provide data from neuroophthalmological testing that shows full preservation of the visual fields with this approach.

Surgical anatomy and surgical approaches to the lateral ventricles

This study focuses on the surgical approaches to intraventricular tumors which have developed within the cavity of the lateral ventricle. The first section is dedicated to embryology and describes the wrapping of the telencephalic vesicles around the thalamus and the morphogenesis of basal nuclei and commissures. In the second section, the anatomy of the lateral ventricles is described, along with their arterial and venous vasculature, their relationship with the eloquent cortical areas and cortical sulci, and their relationship with white matter fascicles, especially the optic radiations. In the third part, the main surgical approaches to the frontal horn, to the ventricular atrium and to the temporal horn are detailed.

Intraventricular glioblastoma multiforme with previous history of intracerebral hemorrhage : a case report

GBM is the most common primary brain tumor, but intraventricular GBM is rare and only few cases have been reported in the literature. The authors report a case of 64-year-old man who had a remote history of previous periventricular intracerebral hemorrhage. Brain computed tomography (CT) and magnetic resonance (MR) imaging showed an intraventricular lesion with inhomogeneous enhancement, infiltrative borders and necrotic cyst, and obstructive hydrocephalus. The patient underwent surgical removal through transcortical route via the bottom of previous hemorrhage site and the final pathologic diagnosis was GBM. We present a rare case of an intraventricular GBM with detailed clinical course, radiological findings, and pathological findings, and the possible origin of this lesion is discussed.

Optic radiations: a microsurgical anatomical study

OBJECT

In this study, the authors used a fiber-dissection technique to describe the optic radiation. They focused on the morphological characteristics (length and breadth) of this structure, its course, and its relationships with neighboring fasciculi and the lateral ventricle.

METHODS

The authors dissected 10 previously frozen, formalin-fixed human brains with the aid of an operating microscope by following the fiber dissection technique described by Klingler in 1960. Lateral, inferior, and medial approaches were made. The optic radiation, also known as the Gratiolet radiation, extended from the lateral geniculate body to the calcarine fissure. The average distance from the tip of the anterior Meyer loop to the calcarine sulcus was 105 mm (range 95-114 mm). The breadth of the optic radiations, one on each side of the brain, averaged 17 mm at the level of the inferior horn (range 15-18 mm). This tract could be divided into three main segments: the anterior or Meyer loop, the body, and the end of the optic radiation. Adjacent anatomical structures included: laterally, the inferior longitudinal fasciculi; medially, the tapetum of the corpus callosum; and the ependyma of the inferior horn of the lateral ventricle.

CONCLUSIONS

Various practical surgical approaches are discussed. The knowledge gained by studying this particular anatomy will help prevent injury to the optic radiations during neurosurgery.

Surgical anatomy of supratentorial midline lesions

Object

In this paper the authors correlate the surgical aspects of deep median and paramedian supratentorial lesions with the connective fiber systems of the white matter of the brain.

Methods

The cerebral hemispheres of 10 cadaveric brains were dissected in a mediolateral direction by using the fiber dissection technique, corresponding to the surgical approach.

Conclusions

This study illuminates the delicacy of the intertwined and stratified fiber laminae of the white matter, and establishes that these structures can be preserved at surgical exploration in patients.