The occipital interhemispheric transtentorial approach: historical perspective and evolution over time.

PURPOSE: Access to the pineal region has always represented a fascinating challenge to the neurosurgeons. Almost equally thrilling is the historical evolution from the hard beginnings with extremely high mortality rates to the current surgical outcomes, with excellent resection rates without long-term morbidity for most of the patients. The purpose of this paper is to provide an overview of the historical evolution of the occipital interhemispheric transtentorial (OITT) approach and its role in the development of access to the pineal region. METHODS: Review of the literature highlights the occipital transtentorial approach from the historical context prior its description and the beginning to the current modifications and new recent insights. RESULTS: The occipital transtentorial approach described initially by Poppen in 1966 has played a key role in the progress and success accessing the pineal area. CONCLUSION: This historical review aims to highlight the extraordinary effort of those neurosurgeons who guided and led the development of one of the most important approaches to the pineal region.

Simplified supine modified park bench / lateral decubitus position using a shoulder pad and a Mayfield head clamp for neurosurgical approach to lesions located in the occipital lobe or the posterior fossa: technical note.

Neurosurgical approach to lesions located in the occipital lobes or in the posterior fossa require very specific and time-consuming patient installations, such as the park bench position, the prone position, or the sitting position. Nevertheless, each of these position present major drawbacks regarding specific installation-related adverse events and potentially serious neurosurgical complications such as venous air embolism, iatrogenic intracranial hypertension, and supratentorial remote hematoma just to cite a few. In order to provide neurosurgeons with a simpler, physiologically-respective, easily tolerated, less time-consuming, and less provider or specific adverse events patient installation, Ochiai (1979) introduced the supine modified park-bench / lateral decubitus position. Given that this patient position has not gained wide visibility among the neurosurgical community despite its obvious numerous advantages over its classic counterparts, we provide our experience using this installation for neurosurgical approach to lesions located in the occipital lobes and in the posterior fossa.

Hypometabolism in the Posteromedial Temporal and Medial Occipital Cortex on Preoperative 2-Deoxy-2-(18F) Fluoro-D-Glucose Positron Emission Tomography Suggests Exacerbation of Visual Field Defects After Surgery for Temporal Lobe Epilepsy: A Retrospective Long-Term Follow-Up Study.

OBJECTIVE: Surgery is a good treatment option for drug-resistant temporal lobe epilepsy (TLE). 2-deoxy-2-(18F) fluoro-D-glucose (FDG) positron emission tomography (PET) is used to detect epileptic foci as hypometabolic lesions in presurgical evaluation. Visual field defects (VFDs) in the contralateral homonymous upper quadrant are common postoperative complications in TLE. This study aimed to quantify VFDs using pattern deviation probability plots (PDPPs) and examine the effect of hypometabolism in FDG-PET on VFDs. METHODS: This study included 40 patients. Both visual fields were assessed using the Humphrey field analyzer preoperatively and 3 months and 2 years postoperatively. PDPPs with <0.5% confidence level counted in the contralateral homonymous upper quadrant. FDG-PET results were compared between groups with (15 patients) and without (24 patients) hypometabolism in the optic radiation. RESULTS: All 40 patients were evaluated by Humphrey field analyzer at 3 months postoperatively and 39 at 2 years postoperatively. The incidence of VFDs 3 months postoperatively was 35/40 (87.5%), and 17/40 (42.5%) patients had severe VFDs. In cases of surgery on the left temporal lobe, ipsilateral eyes appeared to be more significantly affected than contralateral eyes. VFDs were more severe in patients with FDG hypometabolism than in those without hypometabolism in posteromedial temporal and medial occipital cortex (P < 0.01); however, 85% of patients with FDG hypometabolism had a reduced VFD 2 years postoperatively. CONCLUSIONS: PDPP counting is useful for quantifying VFDs. Preoperative dysfunction indicated by preoperative FDG-PET in the posteromedial temporal and medial occipital cortex could enhance VFDs early after TLE surgery.

Temporo-Parieto-Occipital Disconnection by Robot-Assisted Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Refractory Epilepsy in a Pediatric Patient: Proof-of-Principle Case Report and Surgical Nuances.

OBJECTIVE: Magnetic resonance imaging-guided laser interstitial thermal therapy (MRIgLITT) has been proven safe and effective for the treatment of focal epilepsy of different etiologies. It has also been used to disconnect brain tissue in more extensive or diffuse epilepsy, such as corpus callosotomy and hemispherotomy. METHODS: In this study, we report a case of temporo-parieto-occipital disconnection surgery performed using MRIgLITT assisted by a robotic arm for refractory epilepsy of the posterior quadrant. A highly realistic cadaver simulation was performed before the actual surgery. RESULTS: The patient was a 14-year-old boy whose seizures began at the age of 8. The epilepsy was a result of a left perinatal ischemic event that caused a porencephalic cyst, and despite receiving multiple antiepileptic drugs, the patient continued to experience daily seizures which led to the recommendation of surgery. CONCLUSIONS: A Wada test lateralized language in the right hemisphere. Motor and sensory function was confirmed in the left hemisphere through magnetic resonance imaging functional studies and NexStim. The left MRIgLITT temporo-parieto-occipital disconnection disconnection was achieved using 5 laser fibers. The patient followed an excellent postoperative course and was seizure-free, with no additional neurological deficits 24 months after the surgery.

Defining the Temporal and Occipital Lobes: Cadaveric Study with Application to Neurosurgery of the Inferior Brain.

BACKGROUND: For surgical interventions, a precise understanding of the anatomical variations of the brain and defined anatomical landmarks to demarcate the regions of the temporal lobe is essential. Many anatomical studies have facilitated important surgical approaches to the temporobasal region. Because there is considerable sulcal variability, morphological analysis of the brain is imperative. The aim of this study was to define the boundaries of the temporal and occipital lobes and to define the variations in sulci and gyri in the inferior aspect. METHODS: In 110 cerebral hemispheres variations were identified and the major landmarks of the gyral-sulcal pattern at the inferior aspect of the brain were defined. RESULTS: The anatomy of the inferior aspect of the brain is defined in detail by morphological analysis of formalin-fixed hemispheres with a view to informing important surgical approaches. CONCLUSIONS: Since the literature defines no clear separation between the temporal and occipital lobes, certain landmarks such as the preoccipital notch and a basal temporo-occipital line were suggested as ways of making the distinction. The parahippocampal ramus is a constant structure that can be used as a reliable landmark for the posterior end of the hippocampus.

Soft tissue Reconstruction Using Pedicled Trapezius Musculocutaneous Flap for Cranial Bone Flap Infection in the Occipital Region.

When managing cranial bone flap infections, infected bone flaps are typically removed and subsequently replaced with artificial bones 6 to 12 months after the inflammation subsides. However, defects in the occipital region pose challenges due to concerns regarding brain protection when patients lie in the supine position. Herein, the authors report the case of a 73-year-old woman with an occipital bone flap infection, which was successfully managed by reconstruction with a trapezius musculocutaneous flap immediately after removing the infected bone flap. One year and 2 months postoperatively, the wound had fully healed, and the patient remained symptom-free without any complications, such as sunken flap syndrome. Soft tissue reconstruction using pedicled trapezius musculocutaneous flap is a viable strategy for managing occipital bone flap infections. This flap ensures stable blood flow and requires minimal vascular manipulation, thereby reducing operation time as the patient does not need to change position.

The sub-occipital transtentorial approach for pineal region tumors: how I do it.

BACKGROUND: Two major approaches exist for the surgical removal of pineal region tumors: the supracebellar infratentorial and the sub-occipital transtentorial. METHODS: We present the Lyon's technique of the sub-occipital transtentorial approach for pineal region tumors and our tricks to avoid complications. The principle is to expose the pineal region under the occipital lobe and not through the interhemispheric fissure. CONCLUSIONS: The sub-occipital transtentorial approach is a direct, extra cerebral, safe, and effective way to access tumors of the pineal region.

[Modified posterior quadrant disconnection in surgical treatment of drug-resistant epilepsy in a patient with left temporal and occipital lobe malformation]. / Modifitsirovannaya zadnekvadrantnaya diskonnektsiya v khirurgicheskom lechenii farmakorezistentnoi epilepsii u patsienta s porokom razvitiya levykh visochnoi i zatylochnoi dolei.

Adults with large multilobar lesions of temporal, parietal and occipital lobes of the dominant hemisphere suffering from drug-resistant epilepsy were considered inoperable for a long time. OBJECTIVE: To demonstrate favorable postoperative outcome in a patient with massive periventricular heterotopia of the left temporal and occipital lobes complicated by drug-resistant epilepsy. MATERIAL AND METHODS: We analyzed localization of the brain malformation (massive periventricular heterotopia) and its relationship with surrounding structures in a 38-year-old patient considering preoperative MRI, functional MRI and MR tractography data. Quality of modified posterior quadrant disconnection was assessed within a day and 6 months after surgery in accordance with MRI data. Transcranial stimulation, direct cortical and subcortical monopolar stimulation were used for intraoperative monitoring of corticospinal tract. We also assessed neurological status and linguistic testing data before surgery, 4 days and 6 months after surgery. RESULTS: Modified posterior disconnection of temporal, parietal and occipital lobes was performed. Intraoperative neurophysiological cortical mapping (asleep-awake-sedation protocol) verified localization of Wernicke's area. There was an expected right-sided homonymous hemianopsia in postoperative period without speech disorders. Postoperative outcome Engel grade 1A under anticonvulsant therapy was obtained. CONCLUSION: The authors report successful surgical treatment of massive malformation of the left temporal, parietal and occipital lobes and literature review devoted to this issue.

Occipital Interhemispheric Transtentorial Approach for Microsurgical Resection of a Ruptured Vermian Arteriovenous Malformation: Three-Dimensional Operative Video.

Cerebellar arteriovenous malformations (AVMs) are associated with higher risk of rupture compared with cerebral AVMs.1 Microsurgical resection of a ruptured AVM, measuring 3 cm in its largest dimension, within the cerebellar vermis and right parasagittal cerebellar lobe is demonstrated in Video 1. Cerebral angiography showed major supply from both superior cerebellar arteries and minor supply from a right anterior inferior cerebellar artery-posterior inferior cerebellar artery variant. Venous drainage was through a single ectatic vermian vein draining toward the torcula. Intraoperatively, a second, thrombosed, draining vein connected to the vein of Galen was identified. A right interhemispheric occipital transtentorial approach was elected over the supracerebellar infratentorial approach for early access to the superior cerebellar artery feeding arteries and for an orthogonal rather than a tangential view. The patient was positioned in an ipsilateral lateral position with the head turned 45° toward the floor allowing for gravity retraction of the ipsilateral occipital lobe. An external ventricular drain was also inserted to allow for further relaxation of the occipital lobe. Under neuronavigation guidance, the tentorium was opened allowing immediate visualization of the AVM with early control of the superior cerebellar artery arterial feeders. The AVM was removed using standard microsurgical technique, and hematoma was evacuated. Postoperative cerebral angiography demonstrated no AVM residual. The patient was discharged to a rehabilitation institute with minor residual cerebellar deficits. The patient provided written informed consent for the procedure, video recording, and publication.

The posterior interhemispheric transparieto-occipital fissure approach to the atrium of the lateral ventricle: a fiber microdissection study with case series.

The surgical approach to the atrium of the lateral ventricle remains a challenge because of its deep location and close relationship to important neurovascular structures. We present an alternative and safer approach to lesions of the atrium using a natural pathway through the parieto-occipital fissure. We demonstrate this approach through cadaveric anatomical microdissection and a case series. Five formalin-fixed brain specimens (10 hemispheres) were dissected with the Klingler technique. Transillumination was used to show the trajectory of the approach in cadaveric specimens. Clinical data from five patients who underwent this approach were reviewed. This data included intraoperative ultrasound images, operative images, pre- and postoperative magnetic resonance imaging, MR tractography, and visual field examination. The parieto-occipital fissure is a constant, uninterrupted fissure that can be easily identified in cadavers. Our anatomical dissection study revealed that the atrium of the lateral ventricle can be approached through the parieto-occipital fissure with minor damage to the short association fibers between the precuneus and cuneus, and a few fibers of the forceps major. In our series, five patients underwent total resection of their atrial lesions via the posterior interhemispheric transparieto-occipital fissure. No morbidity or mortality was observed, and the disruption of white matter was minimal, as indicated on postoperative tractography. The postoperative visual fields were normal. The posterior interhemispheric transparieto-occipital fissure approach is an alternative to remove lesions in the atrium of the lateral ventricle, causing the least damage to white matter tracts and preserving visual cortex and optic radiation.

Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex.

BACKGROUNDA long-held goal of vision therapy is to transfer information directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight. However, no clinically available cortical visual prosthesis yet exists.METHODSWe implanted an intracortical microelectrode array consisting of 96 electrodes in the visual cortex of a 57-year-old person with complete blindness for a 6-month period. We measured thresholds and the characteristics of the visual percepts elicited by intracortical microstimulation.RESULTSImplantation and subsequent explantation of intracortical microelectrodes were carried out without complications. The mean stimulation threshold for single electrodes was 66.8 ± 36.5 µA. We consistently obtained high-quality recordings from visually deprived neurons and the stimulation parameters remained stable over time. Simultaneous stimulation via multiple electrodes was associated with a significant reduction in thresholds (P < 0.001, ANOVA) and evoked discriminable phosphene percepts, allowing the blind participant to identify some letters and recognize object boundaries.CONCLUSIONSOur results demonstrate the safety and efficacy of chronic intracortical microstimulation via a large number of electrodes in human visual cortex, showing its high potential for restoring functional vision in the blind.TRIAL REGISTRATIONClinicalTrials.gov identifier NCT02983370.FUNDINGThe Spanish Ministerio de Ciencia Innovación y Universidades, the Generalitat Valenciana (Spain), the Europan Union's Horizon 2020 programme, the Bidons Egara Research Chair of the University Miguel Hernández (Spain), and the John Moran Eye Center of the University of Utah.

Avoidance and Improvement in Visual Field Defect After Surgery for Metastatic Brain Tumors in the Parietal and the Occipital Lobe.

OBJECTIVE: Visual field defects occasionally occur secondary to tumors in the parietal and the occipital lobes. The aim of this study was to analyze the efficacy of improvement in hemianopsia after surgery for metastatic brain tumors involving or adjacent to the optic radiation (OR). METHODS: The study included 49 patients with brain metastasis in the parietal and occipital lobes in the present study. Preoperative and postoperative neurological assessments included visual field, Mini-Mental State Examination, and Karnofsky performance scale. RESULTS: Of 49 patients, 33 (67.3%) presented with preoperative homonymous hemianopsia. Of these 33 patients, the visual field was improved postoperatively in 17 patients (51.5%). In all patients regardless of preoperative hemianopsia, postoperative visual fields did not deteriorate. Tractography demonstrated that the OR was split by the tumor (n = 6) and fanning of fibers expanded along the lateral side of the tumor (n = 11). All tumors were removed via surgical access toward the medial side of the tumor. Gross total resection was achieved in most tumors in the group with visual improvement (n = 16/17; 94.1%). Improvement in the visual field was attributed to tumor location in the subcortical white matter, removal rate of the tumor, and higher postoperative Karnofsky performance scale score. CONCLUSIONS: The OR tended to deviate to the lateral side of the tumor in the parieto-occipital junction. The postoperative visual field improved even in cases of an occipital tumor. Based on the present study, total resection via an appropriate surgical route should be considered to preserve the OR, leading to improvement in the postoperative visual field.

Remarkable Clinical Improvement Following Microsurgical Resection of Left Lingual Gyrus Cerebral Cavernous Malformation: A Case Report

Moyamoya disease is a chronic and unusual cerebrovascular disorder characterized by progressive stenosis and occlusion of the distal portions of internal carotid arteries and its main branches within the circle of Willis. Posterior circulation (vertebral and basilar arteries) may also be affected; however, this presentation is uncommon. As well as stenosis of the terminal portion of intracranial arteries, it is seen the development of a network of collateral vessels abnormally dilated at the base of the brain with an aspect of a "puff of smoke," whose term in Japanese is described as "moyamoya." The present study aims to report two consecutive cases of patients who presented to our service with different clinical manifestations. Further investigation with digital subtraction angiography showed a moyamoya pattern.

Brain Abscess Caused by Nocardia: Case Report and Literature Review

Nocardia brain abscess is a rare clinical entity, accounting for 2% of all brain abscesses, associated with high morbidity and amortality rate 3 times higher than brain abscesses caused by other bacteria. Proper investigation and treatment, characterized by a longterm antibiotic therapy, play an important role on the outcome of the patient. The authors describe a case of a patient without neurological comorbidities who developed clinical signs of right occipital lobe impairment and seizures, whose investigation demonstrated brain abscess caused by Nocardia spp. The patient was treated surgically followed by antibiotic therapy with a great outcome after 1 year of follow-up.

Endoscope-assisted posterior quadrant disconnection plus corpus callosotomy: case report.

Intractable epilepsy impacts many children. Surgically resective and palliative treatments have developed to increase seizure freedom or palliate the seizure burden in those with medically refractory epilepsy. However, surgical epilepsy treatment can confer significant morbidity and death. Endoscope-assisted surgical approaches may be helpful in reducing the morbidity related to traditional open surgical approaches while allowing for good visualization of surgical targets. Here, the authors report a case utilizing an endoscope-assisted keyhole approach to perform a posterior quadrantectomy and corpus callosotomy, achieving the surgical goals of disconnection and reducing the need for large craniotomy exposure. They present the case of a 17-year-old male with medically refractory epilepsy treated with endoscope-assisted posterior quadrantectomy and corpus callosotomy through two mini-craniotomies to achieve a functional disconnection. To the authors' knowledge, this is the first reported case of an endoscope-assisted approach for a posterior quadrantectomy for surgical epilepsy treatment in an adult or a pediatric patient. The case is reported to highlight the technical nuances and benefits of this approach in select patients as well as the expansion of applications of endoscope-assisted epilepsy surgery.

Parietal interhemispheric transfalcine transtentorial approach for posterior incisural space lesions: from the lab to the operative room.

The operative approach to the posterior incisural space is challenging because of its deep location, the surrounding eloquent areas, and the intimate relationship with the deep veins. Several approaches have been proposed to manage the lesions in this region: supratentorial, infratentorial and a combination of them. Brain retraction, injury to the occipital lobe and corpus callosum, and venous bleeding are the principle drawbacks of these routes. We performed anatomical dissection study using 10 embalmed human cadaver specimens injected with colored latex exploring a different route, parietal interhemispheric transfalcine transtentorial (PITT). Then we used a PITT approach on two patients with posterior incisural space (PIS) lesions. The PITT approach led to successful and safe complete removal of PIS lesions in our cases. No complications were reported. The present approach could be a valuable option in case of PIS lesions, especially those associated with downward displacement of the deep venous complex; thanks to the gravity it reduce the complications related to the occipital lobe retraction and manipulation. Moreover, cutting the superior-anterior edge of the tentorium, the sub-tentorial space could be reached.

Visual field restoration after Simpson grade I resection of symptomatic occipital lobe meningioma: illustrative case and review of the literature.

Intracranial meningiomas mostly affect patients in their fifth decade and beyond, raising pertinent questions regarding the risk of surgery, particularly in the elderly. Here, we describe the case of a septuagenarian patient with occipital meningioma causing severe visual field cuts that experienced full recovery of the visual function after a Simpson I resection of the lesion. This case illustrates the potential of recovery of the brain, even in the case of severely impaired function in elderly patients. To complete the picture, we review the literature on occipital meningiomas, advocating for systematic reports and increase data collection on post-operative neurological recovery in the elderly.

Muscle Fascia Changes in Patients with Occipital Neuralgia, Headache, or Migraine.

SUMMARY: In an ongoing effort to understand the pathogenesis of occipital neuralgia/headache/migraine, it is critical to describe the anatomical/tissue changes encountered during surgery. Greater occipital nerve anatomical studies mainly focus on the greater occipital nerve course through muscle/fascial planes and interaction with the occipital vessels. However, structural soft-tissue changes have not been described in detail. Anecdotally, trapezius fascia is thickened at the greater occipital nerve trigger site. This study further investigates this observation. Patients undergoing greater occipital nerve decompression surgery were enrolled prospectively in this observational study (n = 92). Tissue changes were recorded intraoperatively. The resulting data were examined. Trapezius fascia was more than 3 mm thick and appeared fibrotic in 86 patients (94 percent), whereas semispinalis muscle appeared normal in all subjects. The greater occipital nerve was macroscopically abnormal, defined as edematous, flattened, and discolored in 29 cases (32 percent). The occipital artery interacted significantly with the greater occipital nerve in 88 percent of cases. The authors conclude that the tissue structure is abnormal in patients undergoing greater occipital nerve decompression surgery. This is the first study that describes the prevalence of thickened and fibrotic appearing trapezius fascia at the occipital trigger site, a phenomenon encountered in the vast majority of patients (94 percent). This structural anomaly has a resemblance to thickened fascial tissues seen in other nerve compression syndromes, and could be related to microtrauma/overuse or actual trauma in the head and neck region.