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.

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.

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.

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.

Case Report: Neurocysticercosis Acquired in Australia.

Neurocysticercosis (NCC) is a disease caused by infection of the central nervous system with the larval stage of the tapeworm Taenia solium. This disease is endemic in many parts of the world, including Africa, Asia, and Latin America, where animal husbandry practices are common such that pigs reared for human consumption ingest feces from humans infected with T. solium. Neurocysticercosis is rarely acquired in economically affluent regions, including North America, Central Europe, Japan, and Australasia, and in countries where pork consumption is discouraged by religious or social practices. In these countries, NCC is usually diagnosed in immigrants or returning travelers who have spent time in endemic regions. Here, we report a case of NCC in a 25-year-old woman presenting with worsening visual symptoms in association with headache, diagnosed previously as a migraine with visual aura. This person had always lived in Australia and had never traveled overseas to a country endemic for T. solium. The unusual features of the clinical presentation and epidemiology are highlighted to raise physicians' awareness that attention needs to be paid to the risk of autochthonous infection occurring in non-endemic countries.

Spontaneous Regression Followed by Rupture of an Untreated Brain Arteriovenous Malformation.

BACKGROUND: Brain arteriovenous malformations (AVMs) are dynamic lesions. Unlike the recruitment of additional vessels and the growth of the nidus over time, which are well reported in the literature, spontaneous regression is much less frequent. Only a handful of cases reporting recanalization of spontaneously regressed AVMs have been published. AVMs that undergo spontaneous regression typically share structural and historical features, including previous hemorrhage, a small nidus, superficial venous drainage, and a single draining vein. Structural features and hemodynamic changes may predispose brain AVMs to spontaneous regression, and angiogenic processes are hypothesized to contribute to recanalization and hemorrhage. CASE DESCRIPTION: We present the case of a 37-year-old female who had been diagnosed 12 years ago with an unruptured Spetzler-Martin grade 3 AVM in the left medial occipital lobe after a history of progressively worsening migraines. The AVM was monitored for 1 year, but the patient was lost to follow-up until 11 years later, when the AVM nidus was found to be significantly smaller in size. One month later, the patient presented with acute intraparenchymal hemorrhage due to rupture of the AVM, which was then surgically resected. CONCLUSIONS: Our case is the second reported case of rupture of a spontaneously regressed AVM and the first reported case of this outcome with no history of previous hemorrhage. Close monitoring of brain AVMs may be warranted for longer periods of time than previously recommended.

Stereotactic MRI-guided laser interstitial thermal therapy for extratemporal lobe epilepsy.

OBJECTIVE: Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRg-LITT) is an alternative to open epilepsy surgery. We assess safety and effectiveness of MRg-LITT for extratemporal lobe epilepsy (ETLE) in patients who are considered less favorable for open resection. METHODS: We retrospectively reviewed sequential cases of patients with focal ETLE who underwent MRg-LITT between 2012 and 2019. Epileptogenic zones were determined from standard clinical and imaging data ± stereoelectroencephalography (SEEG). Standard stereotactic techniques, MRI thermometry, and a commercial laser thermal therapy system were used for ablations. Anatomic MRI was used to calculate ablation volumes. Clinical outcomes were determined longitudinally. RESULTS: Thirty-five patients with mean epilepsy duration of 21.3 ± 12.2 years underwent MRg-LITT for focal ETLE at a mean age 36.4 ± 12.7 years. A mean 2.59 ± 1.45 trajectories per patient were used to obtain ablation volumes of 8.8 ± 7.5 cm3 . Mean follow-up was 27.3 ± 19.5 months. Of 32 patients with >12 months of follow-up, 17 (53%) achieved good outcomes (Engel class I + II) of whom 14 (44%) were Engel class I. Subgroup analysis revealed better outcomes for patients with lesional ETLE than for those who were nonlesional, multifocal, or who had failed prior interventions (P = .02). Of 13 patients showing favorable seizure-onset patterns (localized low voltage fast activity or rhythmic spiking on SEEG) prior to ablation, 9 (69%) achieved good outcomes, whereas only 3 of 11 (27%) who show other slower onset patterns achieved good outcomes. Minor adverse events included six patients with transient sensorimotor neurologic deficits and four patients with asymptomatic hemorrhages along the fiber tract. Major adverse events included one patient with a brain abscess that required stereotactic drainage and one patient with persistent hypothalamic obesity. Three deaths-two seizure-associated and one suicide-were unrelated to surgical procedures. SIGNIFICANCE: MRI-guided laser interstitial thermal therapy (or MRg-LITT) was well-tolerated and yielded good outcomes in a heterogeneous group of ETLE patients. Lesional epilepsy and favorable seizure-onset patterns on SEEG predicted higher likelihoods of success.

Suboccipital, Supracerebellar, Infratentorial Approach for Microsurgical Clipping of a Ruptured Tentorial, Straight Sinus Type Dural Arteriovenous Fistula.

BACKGROUND: Dural arteriovenous fistulas (dAVFs) can often be successfully treated with endovascular embolization; however, surgery is occasionally still required. CASE DESCRIPTION: Herein, we discuss a 65-year-old male patient who presented with a Hunt-Hess IV subarachnoid hemorrhage, intraventricular hemorrhage, and cerebellar intracranial hemorrhage secondary to a ruptured Borden type III tentorial (straight sinus) dAVF. Angiography revealed supply from the left occipital and posterior meningeal arteries and direct drainage into the cerebellar cortical veins with venous aneurysms in both cerebellar hemispheres. Both transarterial and transvenous embolization were attempted, without success. Therefore, the patient was taken to the operating room for clip ligation of the dAVF. The operative video demonstrates a bilateral suboccipital craniotomy and supracerebellar infratentorial approach for surgical clipping of the dAVF. CONCLUSIONS: The case and operative video provide a valuable addition to surgical literature in an era where surgical management of dAVFs has become relatively rare.