Interhemispheric Transcallosal Research Articles

Periventricular and Intraventricular Tumors in a Low-Income Country: Hard Learning Curve and Outcome of a Young Neurosurgeon from Burkina Faso

Background: Periventricular and Intraventricular processes are life-threatening conditions because of their propensity to obstruct Cerebrospinal fluid pathways and to compress highly functional and vital structures. There are deep-seated lesions requiring rigorous microsurgical technic for their resection. Methods: We retrospectively analyzed the profile and outcome of Periventricular and intraventricular processes operated by the same author since his return in his country in 2015, after graduated abroad in WFNS Rabat training center program 2023. Result: We defined 15 patients operated over 8 years. There were 4 processes in lateral ventricle (26.6%), 1 in third ventricle (6.6%), 2 thalamus processes (13.3%), 4 in fourth ventricle (26.6%) and finally 4 in cerebellar hemisphere and violating the fourth ventricle (26.6%). Various surgical approaches were used, such as contralateral interhemispheric transcallosal, classical interhemispheric transcallosal, Subfrontal transbasal translamina terminalis, Frontal Transcortical, Temporal trans T2, ventriculoperitoneal shunting, endoscopy, cerebellar transcotical approach and Telovelar approach. Surgical procedure duration was more than 10 hours in 12 cases (80%) and one third of the patients have been operated in 2018. When neurosurgical operative microscope was not available, ophthalmologic microscope or binocular with headlight were used to achieve the resection. Pathological examination revealed High-grade glioma, subependymal giant cell astrocytoma (SEGA), central neurocytoma, Subependymoma, Hemangioblastoma, pilocytique astrocytoma, Medulloblastoma, gemiocytic astrocytoma, atypical papilloma of choroid plexus, craniopharygioma and cyst of septum pellucidum. We reported good postoperative outcome in 10 cases (66.6%), moderate postoperative deficit in 1 case and 4 cases of postoperative death (26.6%) among which 3 cases of postoperative meningitis. Conclusion: Periventricular and intraventricular processes can be safely approach in low-income country with acceptable result. However young African Neurosurgeon should be trained to be comfortable with multiple surgical approaches and also with binocular as well as with microscope. WFNS training program is a strong basement for the take-off of young African neurosurgeon. Backing home should be the rule after training, to develop neurosurgery.

Suprasellar Immature Teratoma in A 20-year-old Male: A Case Report

Background: Immature teratomas are very rare in adults, especially in the suprasellar area, but they should be considered in the differential diagnosis, particularly when dealing with tumors located in the midline structure. Case presentation: In this study, we present a rare case of an immature teratoma in the suprasellar region of a 20-year-old male. A contrast-enhanced brain MRI revealed a multilocular cystic mass in the suprasellar area, accompanied by non-communicating hydrocephalus. To alleviate intracranial pressure, a shunting procedure was performed to redirect the cerebrospinal fluid. Moreover, tumor resection was carried out using an interhemispheric transcallosal approach. Conclusion: Histopathological examinations unveiled the presence of all three germ layers, followed by immature tissue, consistent with the features of an immature teratoma.

Anatomical surgical approach to lateral vetricle masses and histopathological findings of the brain.

The selection of surgical approach to the lateral ventricular masses includes difficulties due to their deep localizations, close proximity to the vascular and the eloquent brain structures. The most appropriate approach that should be chosen in surgical treatment of lateral ventricular masses is still controversial. In this study, the factors in the choice of surgical approach to the lateral ventricle masses and the results of them were investigated. In this study, 80 patients who underwent surgery in our clinic due to the lateral ventricular masses were retrospectively analyzed between the years 2002-2013. All of the cases were evaluated in terms of clinical and neuroradiological results pre and postoperatively. In 24 cases the anterior interhemispheric transcallosal, in 4 cases the posterior interhemispheric transcallosal, in 30 cases the posterior interhemispheric precuneal, in 14 cases the transcortical and in 8 cases the combined surgical approaches were performed. Gender distribution of the cases were 45 male/35 female and the mean age of them was 31.7 years (7 month - 73 years). In 64 patients the gross total resection was performed, whereas in 16 patients subtotal resection was performed due to the infiltration of eloquent brain areas. In the histopathological examination; 52 neuroepithelial, 8 mixed neuroglial, 3 meningeal, 2 lympho-hematopoietic system, 1 pine blastoma, 1 germ cell, 5 metastatic and 8 other benign masses were observed. After surgery, additional neurological deficits developed in 9 patients. The mortality was observed in 6 patients postoperatively. The average follow-up time was 13 (1-83) months. The essential factors which affect the results of surgical treatment of lateral ventricular masses are; the size of the mass, histopathology, location, extension, and the relationship to the neurovascular structures. The goal of surgery is to provide the histopathological diagnosis, gross total resection, if it is possible, and to normalize the flow of cerebrospinal fluid by eliminating the mass effect of pressure.

BRAF-mutated suprasellar glioblastoma mimicking craniopharyngioma: illustrative case.

Suprasellar masses commonly include craniopharyngiomas and pituitary adenomas. Suprasellar glioblastoma is exceedingly rare with only a few prior case reports in the literature. Suprasellar glioblastoma can mimic craniopharyngioma or other more common suprasellar etiologies preoperatively. A 65-year-old male with no significant history presented to the emergency department with a subacute decline in mental status. Work-up revealed a large suprasellar mass with extension to the right inferior medial frontal lobe and right lateral ventricle, associated with significant vasogenic edema. The patient underwent an interhemispheric transcallosal approach subtotal resection of the interventricular portion of the mass. Pathological analysis revealed glioblastoma, MGMT partially methylated, with a BRAF V600E mutation. Malignant glioblastomas can mimic benign suprasellar masses and should remain on the differential for a diverse set of brain masses with a broad range of radiological and clinical features. For complex cases accessible from the ventricle where the pituitary complex cannot be confidently preserved via a transsphenoidal approach, an interhemispheric approach is also a practical initial surgical option. In addition to providing diagnostic value, molecular profiling may also reveal therapeutically significant gene alterations such as BRAF mutations.

Microsurgical management of midbrain gliomas: surgical results and long-term outcome in a large, single-surgeon, consecutive series.

The authors report on a large, consecutive, single-surgeon series of patients undergoing microsurgical removal of midbrain gliomas. Emphasis is put on surgical indications, technique, and results as well as long-term oncological follow-up. A retrospective analysis was performed of prospectively collected data from a consecutive series of patients undergoing microneurosurgery for midbrain gliomas from March 2006 through June 2022 at the authors' institution. According to the growth pattern and location of the lesion in the midbrain (tegmentum, central mesencephalic structures, and tectum), one of the following approaches was chosen: transsylvian (TS), extreme anterior interhemispheric transcallosal (eAIT), posterior interhemispheric transtentorial subsplenial (PITS), paramedian supracerebellar transtentorial (PST), perimedian supracerebellar (PeS), perimedian contralateral supracerebellar (PeCS), and transuvulotonsillar fissure (TUTF). Clinical and radiological data were gathered according to a standard protocol and reported according to common descriptive statistics. The main outcomes were rate of gross-total resection; extent of resection; occurrence of any complications; variation in Karnofsky Performance Status score at discharge, 3 months, and last follow-up; progression-free survival (PFS); and overall survival (OS). Fifty-four patients (28 of them pediatric) met the inclusion criteria (6 with high-grade and 48 with low-grade gliomas [LGGs]). Twenty-two tumors were in the tegmentum, 7 in the central mesencephalic structures, and 25 in the tectum. In no instance did the glioma originate in the cerebral peduncle. TS was performed in 2 patients, eAIT in 6, PITS in 23, PST in 16, PeS in 4, PeCS in 1, and TUTF in 2 patients. Gross-total resection was achieved in 39 patients (72%). The average extent of resection was 98.0% (median 100%, range 82%-100%). There were no deaths due to surgery. Nine patients experienced transient and 2 patients experienced permanent new neurological deficits. At a mean follow-up of 72 months (median 62, range 3-193 months), 49 of the 54 patients were still alive. All patients with LGGs (48/54) were alive with no decrease in their KPS score, whereas 42 showed improvement compared with their preoperative status. Microneurosurgical removal of midbrain gliomas is feasible with good surgical results and long-term clinical outcomes, particularly in patients with LGGs. As such, microneurosurgery should be considered as the first therapeutic option. Adequate microsurgical technique and anesthesiological management, along with an accurate preoperative understanding of the tumor's exact topographic origin and growth pattern, is crucial for a good surgical outcome.

Lateral ventricle subependymoma resected with a transcallosal approach: illustrative case.

Subependymomas are World Health Organization grade I tumors, and 30% occur in the lateral ventricles. Surgery is the mainstay of treatment, and the transcallosal or transcortical/transsulcal approaches are preferred for those tumors occurring near the foramen of Monro or atrium. Visualization, proximity to the fornix and basal ganglia, hydrocephalus, and brain retraction during surgery make these operations challenging. The authors present the case of a 65-year-old male with a subependymoma located in the left lateral ventricle. The tumor was completely resected using an interhemispheric/transcallosal approach. The authors analyze the anatomopathological features of subependymoma, along with the clinical behavior and therapeutic options. The authors discuss in detail the advantages and disadvantages of the interhemispheric/transcallosal approach for resection of these tumors. Subependymomas are slow-growing lesions with an indolent yet complicated course making surgical removal challenging yet feasible using the correct techniques. The interhemispheric transcallosal approach offers an excellent route for the resection of large subependymomas, but there is still a significant risk for postoperative complications.

Anatomical step-by-step dissection of common approaches to the third ventricle for trainees: surgical anatomy of the anterior transcortical and interhemispheric transcallosal approaches, surgical principles, and illustrative pediatric cases.

To create a high-quality, cadaver-based, operatively oriented resource documenting the anterior transcortical and interhemispheric transcallosal approaches as corridors to the third ventricle targeted towards neurosurgical trainees at all levels. Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic-assisted visualization. Dissections of the transcortical and transcallosal craniotomies with transforaminal, transchoroidal, and interforniceal transventricular approaches were performed. The dissections were documented in a stepwise fashion using three-dimensional photographic image acquisition techniques and supplemented with representative cases to highlight pertinent surgical principles. The anterior transcortical and interhemispheric corridors afford excellent access to the anterior two-thirds of the third ventricle with varying risks associated with frontal lobe versus corpus callosum disruption, respectively. The transcortical approach offers a more direct, oblique view of the ipsilateral lateral ventricle, whereas the transcallosal approach readily establishes biventricular access through a paramedian corridor. Once inside the lateral ventricle, intraventricular angled endoscopy further enhances access to the extreme poles of the third ventricle from either open transcranial approach. Subsequent selection of either the transforaminal, transchoroidal, or interforniceal routes can be performed through either craniotomy and is ultimately dependent on individual deep venous anatomy, the epicenter of ventricular pathology, and the concomitant presence of hydrocephalus or embryologic cava. Key steps described include positioning and skin incision; scalp dissection; craniotomy flap elevation; durotomy; transcortical versus interhemispheric dissection with callosotomy; the aforementioned transventricular routes; and their relevant intraventricular landmarks. Approaches to the ventricular system for maximal safe resection of pediatric brain tumors are challenging to master yet represent foundational cranial surgical techniques. We present a comprehensive operatively oriented guide for neurosurgery residents that combines stepwise open and endoscopic cadaveric dissections with representative case studies to optimize familiarity with third ventricle approaches, mastery of relevant microsurgical anatomy, and preparation for operating room participation.

Cavernous Malformations: What They Have Taught Us.

Cavernous Malformations: What They Have Taught Us.

Anterior Inter-hemispheric Transcallosal Approach for Resection of Colloid Cyst: A Video Abstract

Abstract Background Although histologically benign, colloid cysts have been an entity of interest to neurosurgeons due to the wide array of possible presentations ranging from asymptomatic to high ICP symptoms to sudden death. It is estimated that colloid cysts represent 0.3 to 2% of all brain tumors.1 As they are typically located in the third ventricle, multiple approaches have been adapted and developed for the maximum resection with the least complications given the sensitive anatomy in the area.1 2 The interhemispheric transcallosal approach can be safely performed to fully resect a third ventricle colloid cyst with close to zero recurrence rate and minimal to none permanent deficits.3 This video is an educational illustration of the surgical technique and the related anatomy for the interhemispheric transcallosal approach and how to provide best chances of a benign postoperative course. Case Description In this surgical video, we present a case of a 20-year-old male, a known case of hypertension and un-controlled diabetes type-1, presented to our hospital with on and off headache, dizziness, and diplopia that gradually progressed. His neurological exam was unremarkable including memory function. CT and MRI scans demonstrated a rounded sharply demarcated lesion at the at the roof of the third ventricle, measuring 1 × 1 cm in size. The patient underwent an anterior inter-hemispheric transcallosal approach, with gross total resection of the cyst. In the follow-up office visit, the patient headache has resolved, and he had no seizures with preserved memory functions. Conclusion When removal of the colloid cyst is indicated, the interhemispheric transcallosal approach can be performed safely with gross total resection and minimal neurological deficit. This is a surgical demonstration of the transcallosal approach showcasing the surgical corridors and related anatomy.

Balloon-Assisted Corpus Callosotomy. Reducing the Impact of Transcallosal Approaches.

The interhemispheric transcallosal approach is widely used to remove intraventricular lesions. Corpus callosotomy gives immediate access to the ventricular chambers but is invasive in nature. Loss of callosal fibers, although normally tolerate, may cause disturbances ranging from a classical disconnection syndrome up to minor neuropsychological changes. To open an operative window in the corpus callosum through separation rather than disconnection of the white matter fibers. In 7 patients undergoing the interhemispheric transcallosal approach for intraventricular lesions, lying around or below the foramen of Monro, a stoma was created within the corpus callosum by using a 4F Fogarty catheter. The series included 3 colloid of the third ventricle, 2 thalamic cavernomas, 1 subependymoma, and 1 ependymoma of the foramen of Monro. We illustrate the technique and the clinico-radiological outcome, focusing on the size of callosotomy as seen on postoperative MRI. The balloon-assisted corpus callosotomy provided a circular, smooth-walled access to the ventricular chambers, which allowed uncomplicated removal of the lesions. On postoperative MRI, the size of the callosotomy shrinked compared with surgery (2.8-6.4 mm at follow-up vs 6-9 mm as measured intraoperatively). No signs of disconnection syndrome or new permanent deficits were observed in this series. The balloon-assisted technique produces a small callosotomy, without clinical consequences, showing a self-closing trend on postoperative MRI. This technique is a rewarding tool to reduce the impact of callosotomy while keeping the advantages of microsurgical interhemispheric approaches.

Preservation of frontal white matter tracts in ventricular surgery: favoring an anterior interhemispheric transcallosal approach vs a transcortical transfrontal transventricular approach.

Secondary to the creation of a surgical corridor and retraction, white matter tracts degenerate, causing long-term scarring with potential neurological consequences. Third and lateral ventricle tumors require surgery that may lead to cognitive impairment. Our objective is to compare the long-term consequences of a transcortical transfrontal approach and an interhemispheric transcallosal approach on corpus callosum and frontal white matter tracts degeneration. Surgical patients with ventricular tumor accessible through both approaches were included and clinico-radiological data were retrospectively analyzed. The primary endpoint was the callosotomy length at 3-month post-operative T1 MRI, corrected by the extension of the tumor and the use of neuronavigation. Secondary outcomes included perioperative criteria such as bleeding, use of retractors and duration, FLAIR hypersignal on 3-month MRI, and re-do surgeries. To assess white matter tract interruption, 3-month FLAIR hypersignal was superposed to a tractography atlas. Seventy patients were included, 57 (81%) in the transfrontal group and 13 (19%) in the interhemispheric group. There was no difference in the mean callosotomy length on 3-month MRI (12.3mm ± 5.60 transfrontal vs 11.7mm ± 3.92 interhemispheric, p = 0.79) on univariate and multivariate analyses. The callosotomy length was inferior by - 3.13mm for tumors located exclusively in the third ventricle (p = 0.016), independent of the approach. Retractors were used more often in transfrontal approaches (60% vs 33%, p < 0.001). The extent of frontal FLAIR hypersignal was higher after transfrontal approach (14.1mm vs 0.525mm, p < 0.001), correlated to the use of retractors (p < 0.05). After the interhemispheric approach, no tract other than corpus callosum was interrupted, whereas, after the transfrontal approach, frontal arcuate fibers and projections from the thalamus were interrupted in all patients, the cingulum in 19 (33%), the superior fronto-occipital fasciculus in 15 (26%), and the superior longitudinal fasciculus in 2 (3%). Transfrontal and interhemispheric approaches to the third and lateral ventricles both lead to the same long-term damage to the corpus callosum, but the transfrontal approach interrupts several white matter tracts essential to cognitive tasks such as attention and planning, even in the non-dominant hemisphere. These results encourage all neurosurgeons to be familiar with both approaches and favor the interhemispheric approach when both can give access to the tumor with a comparable risk. Neuropsychological studies are necessary to correlate these anatomical findings to cognitive outcomes.

Commentary: Step-by-Step Guide on How to Make a 2-Dimensional Operative Neurosurgical Video: Microsurgical Resection of Right Lateral Ventricle Subependymoma by an Anterior Interhemispheric Transcallosal Approach.

Research Department, Association of Future African Neurosurgeons, Yaounde, Cameroon Correspondence: Ulrick Sidney Kanmounye, MD, Research Department, Association of Future African Neurosurgeons, Immeuble Nziko, Rue Marie Gocker, PO Box 419, Yaounde, Cameroon. Email: [email protected] Twitter: @ulricksidney

Step-by-Step Guide on How to Make a 2-Dimensional Operative Neurosurgical Video: Microsurgical Resection of a Right Lateral Ventricle Subependymoma by an Anterior Interhemispheric Transcallosal Approach.

Digital video recordings are increasingly used across various medical and surgical disciplines with advances in computer hardware and software technologies. The creation of high-quality surgical video footage requires a basic understanding of key technical considerations, together with creativity and sound aesthetic judgment. Online operative videos have become a core resource within neurosurgical education. To provide a step-by-step description for making operative videos using a video from a real case as an example. We recorded an operative video of the microsurgical resection of a right lateral ventricle subependymoma performed by an anterior interhemispheric transcallosal approach. The patient consented to surgical resection of the subependymoma and to publication of this operative video. With the video, we explain the step-by-step process the authors used for developing the raw video into a publishable surgical video. The patient depicted in our video tolerated the surgery well and made a complete recovery. The final video produced from the surgery illustrated elements that Operative Neurosurgery, Neurosurgery, and other journals require in surgical videos. Although more than 1200 peer-reviewed (PubMed) neurosurgical operative videos have been published so far, there has not been a single publication that describes the step-by-step process of producing an operative video. To the best of our knowledge, this is the first published detailed description of editing of an educational operative video in neurosurgery and the first video case report of a microsurgical resection of subependymoma of the lateral ventricle in the peer-reviewed English literature.

The Extreme Anterior Interhemispheric Transcallosal Approach for Pure Aqueduct Tumors: An Anatomical Study.

The cerebral aqueduct is a deep structure located in the diencephalon. It is part of the ventricular system and connects the third and fourth ventricles. The aqueduct has three portions: superior, medial, and inferior. Pure aqueduct tumors occur in the superior portion, and lesions located within the aqueduct are difficult to remove through conventional approaches. Most aqueduct tumors are biopsied and accompanying hydrocephalus is addressed through an endoscopic third ventriculostomy (ETV). The extreme anterior interhemispheric transcallosal approach makes use of a natural corridor to remove aqueduct lesions. Herein, we describe the detailed anatomy of this approach for resecting pure aqueduct tumors in the superior portion of the aqueduct. We aimed to show the normal anatomy of the cerebral aqueduct and the feasibility of the approach to remove tumors within the aqueduct. Ten human brain hemispheres and one cadaveric head were dissected under an operative microscope with 6x to 40x magnification. The cerebral aqueduct anatomy was delineated along with the relationship to nearby structures in the extreme anterior interhemispheric transcallosal approach. We described the anatomy of the cerebral aqueduct within the brain and showed that, with the proper angle for the extreme anterior interhemispheric transcallosal approach, lesions in the cerebral aqueduct can be reached in a single session without damaging periventricular structures. The extreme anterior interhemispheric transcallosal approach provides a direct corridor to the cerebral aqueduct and, thus, is feasible for resecting pure aqueduct tumors in an already dilated intraventricular foramen.

Microsurgical endoportal MRI/US-navigated approach for the resection of large intraventricular tumours: a 20-consecutive patients case series

Objectives Deep lesions located in lateral and third ventricles can be accessed thorough interhemispheric transcallosal or transcortical trans-ventricular approaches. Traditional brain retractors are made by ‘non-cerebral engineered’ spatulas, which do not equally distribute pressure on surrounding structures damaging brain. In this paper, we present a series of 20 intraventricular tumours resected through a MRI/US-navigated microscopic transcortical endoportal approach. Patients and methods Between January 2014 and December 2017, 20 patients underwent US-MRI neuronavigated (Esaote®, Genova, Italy) transcortical endoportal (Vycor® Viewsite Brain Access System TC Model, Vycor® Medical Inc., Boca Raton, FL) surgery for intraventricular deep-seated lesions with the intent to reach maximal safe resection. Results Gross total removal was achieved in 14 patients (70%). The only prognostic factor that resulted in statistical significance related to surgical radicality from multivariate analysis was white matter infiltration (p = 0.043), regardless of other tumour (dimensions, origin and location inside ventricular system, histopathology) and patient (age, gender, clinical presentation) characteristics. The mean duration of surgery was 225.9 min (± 59). Neither critical events, nor major bleedings, nor intraoperative deaths occurred during surgery. One case of postoperative CSF infection (5%) was registered. Six patients (30%) required permanent CSF drainage system (Ommaya reservoir, VP shunt) in the postoperative period. The mean Functional Independence Measure (FIM) score at last follow-up was 105 (range: 65–124). Conclusions Transcortical transventricular endoportal surgery seems to be a valuable alternative to transcallosal surgery, although further prospective multicentre studies with larger number of patients, evaluation of pre- and post-operative neuropsychological outcomes and achievement of postoperative DTI and f-MRI are needed to confirm our results.

The Anterior Interhemispheric Transcallosal Approach in Craniopharyngiomas

Objective: Craniopharyngioma is a type of embryo-epithelium tumor which originates from the remnant tissue of Rathke’s pouch, and the tumor mostly grows in saddle. These tumors are associated with significant morbidity and mortality, primarily from their anatomic proximity to many critical neurological and vascular structures. This study aimed to summarize the clinical experiences and postoperative effects of the transcallosal approach for craniopharyngiomas. Methods: A retrospective analysis was performed on 14 consecutive patients with craniopharyngioma who underwent surgical resection via anterior transcallosal route at the department of Neurosurgery of Cherchell Hospital between January 2015 and June 2020. All patients had thorough preoperative and postoperative ophthalmological and endocrine evaluations. The follow-up period ranged from 10 to 36 months. Results: Gross total resection was achieved in eight patients (57%) in this series. Six patients (43%) with preoperative visual impairment experienced significant visual improvement. The overall recurrence rate was 36%. Conclusion: The interhemispheric transcallosal approach can be used alone for purely intraventricular craniopharyngiomas, or they can be used in combination with other anterolateral and midline transcranial approaches to respect the intra and extra ventricular portions of the tumor.

Interhemispheric transcallosal transchoroidal approach to a pineal teratoma in a 15-year-old boy.

In this video, the authors present an interhemispheric transcallosal transchoroidal approach to a pineal mass in a 15-year-old boy. He received emergency endoscopic third ventriculostomy (ETV), then an endoscopic biopsy that revealed an immature teratoma. Surgical removal was selected. The mass was located very high in the posterior third ventricle, hidden behind the splenium of the corpus callosum and the vein of Galen, so an interhemispheric transcallosal approach followed by a complete dissection of the whole choroidal fissure was chosen and allowed complete removal of the tumor. Microsurgical dissection is presented, showing clearly in detail all the neurovascular structures encountered.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2126.

Interhemispheric transcallosal intervenous approach to a pineal region tumor.

Pineal region tumors represent a formidable challenge to the neurosurgeon. Choosing the right approach is key to optimizing the extent of resection and minimizing surgical morbidity. In this video, the authors show an interhemispheric transcallosal approach to a pineal region tumor in a 15-year-old boy. The advantage of this corridor over posterior approaches is that it provides a nice view of the tumor plane with the venous complex, especially while dissecting tumor from the anterior aspect of the internal cerebral veins on their vertical path. Thus, this approach represents a safe and effective alternative for selected pineal tumors.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2120.

Retractorless interforniceal approach for microsurgical resection of a papillary tumor of the pineal region: operative video and technical nuances.

In this illustrative video, the authors demonstrate microsurgical resection of a papillary tumor of the pineal region using a retractorless interforniceal approach via the anterior interhemispheric transcallosal route. The tumor presented to the posterior third ventricle occluding the cerebral aqueduct, resulting in obstructive hydrocephalus. The retractorless interforniceal approach is performed in the lateral position with BICOL collagen spacers to keep the corridor open. Gross-total resection was achieved, and the patient was neurologically intact without needing a permanent shunt. The operative nuances and pearls of technique for safe microdissection and gentle handling of the retractorless interforniceal approach are demonstrated.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2139.

Resection of a recurrent pineal region teratoma via a posterior interhemispheric transcallosal approach.

The authors describe the unusual case of a 6-year-old boy presenting with decorticate posturing, diminished hearing, and an inability to open his eyes, despite being verbally responsive. He underwent a posterior interhemispheric transcallosal intervenous approach for resection of a pineal region mature teratoma, which recurred 2 years postoperatively. This video demonstrates his initial surgery and reresection, illustrating the value of this approach for more complex lesions that involve the internal cerebral veins (ICVs). At the time of recurrence, microsurgical dissection of the scarred interhemispheric fissure was required to facilitate removal of the multifocal recurrent teratoma, resulting in gross-total resection.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2134.