Surgical indications and microsurgical anatomy of the transchoroidal fissure approach for lesions in and around the ambient cistern

OBJECTIVE: Opening the temporal part of the choroidal fissure (CF) makes it possible to expose the crural cistern, the ambient cistern, and the medial temporal lobe. We examined the microsurgical anatomy and the surgical indications for use of the trans-CF approach. METHODS: The microsurgical anatomy encountered in the trans-CF approach for lesions in and around the ambient cistern was studied in three cadavers. On the basis of these cadaveric studies, the trans-CF approach was used during surgery in three live patients with such lesions. RESULTS: The angiographic "plexal point," which indicates the entrance of the anterior choroidal artery as it enters the temporal horn of the lateral ventricle, was thought to be a key anatomic landmark of the trans-CF approach. A cortical incision for entry into the temporal horn should be made in the inferior temporal gyrus to minimize the potential damage to the optic radiations and to the speech centers. After the CF is opened posteriorly to the plexal point between the tenia fimbria and the choroid plexus, the posterior cerebral artery (PCA) in the ambient cistern can be observed with minimal caudal retraction of the hippocampus. In this study, surgical procedures using the trans-CF approach were successfully performed on patients with high-positioned P2 aneurysms whose PCA ran close to the plexal point or higher, whose medial temporal arteriovenous malformations were fed mainly by the PCA, and whose tentorial hiatus meningiomas protruded into the temporal horn through the CF, with no resulting postoperative visual or memory disturbances. CONCLUSION: The trans-CF approach is especially useful in surgery for lesions in and around the ambient cistern.     

Microsurgical approaches to the perimesencephalic cisterns and related segments of the posterior cerebral artery: comparison using a novel application of image guidance

OBJECTIVE: To describe the exposure obtained through six approaches to the perimesencephalic cisterns with an emphasis on exposure of the posterior cerebral artery and its branches. METHODS: Dissections in 12 hemispheres exposed the crural, ambient, and quadrigeminal cisterns and related segments of the posterior cerebral artery. A Stealth Image Guidance workstation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used to compare the approaches. RESULTS: The transsylvian approach exposed the interpeduncular and crural cisterns. The subtemporal approach exposed the interpeduncular and crural cisterns as well as the lower half of the ambient cistern. Temporal lobe retraction and the position of the vein of Labbé limited exposure of the quadrigeminal cistern. Occipital transtentorial and infratentorial supracerebellar approaches exposed the quadrigeminal and lower two-thirds of the ambient cistern. Transchoroidal approaches exposed the posterior third of the crural cistern, the upper two-thirds of the ambient cistern, and the proximal quadrigeminal cistern. Transchoroidal approaches exposed the posterior portion of the P2 segment (P2p) in 9 of 10 hemispheres and were the only approaches that exposed the lateral posterior choroidal arteries and the plexal segment of the anterior choroidal artery. Occipital transtentorial and infratentorial supracerebellar approaches provided access to the P3 segment in all cases and exposed the P2p segment in 4 of 10 hemispheres. The subtemporal approach provided access to the cisternal and crural segments of the anterior choroidal and medial posterior choroidal arteries and exposed the P2p segment in 3 of 10 hemispheres. CONCLUSION: Surgical approaches to lesions of the perimesencephalic cisterns must be tailored to the site of the pathological findings. The most challenging area to expose is the upper half of the ambient cistern, particularly the P2p segment of the posterior cerebral artery.     

Microsurgical anatomy of the choroidal fissure

The microsurgical anatomy of the choroidal fissure was examined in 25 cadaveric heads. The choroidal fissure, the site of attachment of the choroid plexus in the lateral ventricle, is located between the fornix and thalamus in the medial part of the lateral ventricle. The choroidal fissure is divided into three parts: (a) a body portion situated in the body of the lateral ventricle between the body of the fornix and the thalamus, (b) an atrial part located in the atrium of the lateral ventricle between the crus of the fornix and the pulvinar, and (c) a temporal part situated in the temporal horn between the fimbria of the fornix and the lower surface of the thalamus. The three parts of the fissure are the thinnest sites in the wall of the lateral ventricle bordering the basal cisterns and the roof of the third ventricle. Opening through the body portion of the choroidal fissure from the lateral ventricle exposes the velum interpositum and third ventricle. Opening through the temporal portion of the choroidal fissure from the temporal horn exposes the structures in the ambient and crural cisterns. Opening through the atrial portion of the fissure from the atrium exposes the quadrigeminal cistern, the pineal region, and the posterior portion of the ambient cistern. The neural, arterial, and venous relationships of each part of the fissure are reviewed. The operative approaches directed through each part of the fissure are also reviewed.     

The transsylvian trans-limen insular approach to the crural,ambient and interpeduncular cisterns

Summary Background. The authors introduce the transsylvian trans-limen insular approach to the crural, ambient and interpeduncular cisterns.Method. The transsylvian trans-limen insular approach was performed in 7 patients; 3 for aneurysm, 2 for isolated temporal horn hydrocephalus, one for tumour and one for an arteriovenous malformation. This approach is summarized in 4 procedures; the exposure of the inferior limiting sulcus of the insular cortex, the exposure of the inferior horn of the lateral ventricle, the dissection of the inferior part of the choroidal fissure and the splitting of the inferior border of the limen insula.Findings. Four among 7 patients underwent surgery for the lesions in the crural or ambient cistern. The other 3 patients underwent surgery for the lesion in the interpeduncular cistern. Two patients of the latter group postoperatively had temporal lobe infarction.Conclusions. The transsylvian trans-limen insular approach may be indicated for lesions in the crural and the anterior ambient cisterns, and the lesions which need wider exposure of the interpeduncular cistern. For the former lesions, this approach can afford good results. For the latter lesions, careful brain retraction and some other techniques to avoid temporal lobe infarction are necessary. Further neuropsychological assessment should be also necessary to prove the validity of this approach.     

How I do it – selective amygdalohippocampectomy via subtemporal approach

Background

Surgery is superior over medicamentous treatment of pharmacoresistant mesial temporal lobe epilepsy caused by hippocampal sclerosis. The armamentarium of surgical procedures comprises standard temporal lobectomy and more selective procedures. Selective amygdalohippocampectomy can be performed via transcortical, transsylvian or subtemporal approach.

Method

Describe the selective amygdalohippocampectomy through the subtemporal approach

Conclusion

After the detailed preoperative epilepsy evaluation, surgery can be offered to pharmacoresistant epilepsy patient with hippocampal sclerosis. Selective amygdalohippocampectomy can be safely performed through the subtemporal approach. The good knowledge of the mesial temporal lobe anatomy is necessary when performing this procedure.

Key points

? Perform the subtemporal craniotomy with additional bone removal up to temporal petrous part to minimize retraction of the brain. ? Release the CSF from the subarachnoid sulcal space in order to relax the temporal lobe. Dissect the arachnoid around basal temporal veins and protect them with hemostatic material in order to avoid vein rupture. ? After gyrus fusiformis corticotomy, always follow the white matter in order to enter the temporal horn. ? Place the self-retraining retractor gently to secure an unobstructed view of the intraventricular mesial temporal lobe structures. ? Visualize the choroid plexus and the inferior choroidal point. They represent the two most important landmarks. ? While performing the anterior disconnection the goal is to reach the arachnoid of the interpeduncular and crural cistern medially and the tentorial edge laterally. ? Follow the tentorial edge and the arachnoid of the temporal base to securely perform the lateral disconnection. ? Perform the posterior disconnection at the level of the mesencephalon superior colliculi. ? During the medial disconnection the dissection of the arachnoid of the hippocampal sulcus must be done as close to the hippocampus as possible in order to avoid damage to the brain stem perforators or the loop of the anterior choroidal artery. ? Knowledge of mesial temporal lobe anatomy is crucial.     

Endoscopic transchoroidal and transforaminal approaches for resection of third ventricular colloid cysts

To review our experience over 10 years in endoscopic resection of third ventricular colloid cysts, describing the details of the transventricular–transchoroidal approach used in selected patients. This series included 24 patients with colloid cysts of the third ventricle treated in our department between October 2001 and January 2013 using an endoscopic approach. Clinical presentation, preoperative radiological findings, endoscopic technique employed, and complications were assessed in all patients. The mean length of patient follow-up was 5.16 years. The most common symptom was headache (75 %). The average size of the resected colloid cysts was 16.25 mm, the maximum diameter measured in cranial magnetic resonance imaging. Resection was transforaminal in 16 cases (66.7 %), transchoroidal in 7 (29.17 %), and transseptal in 1; macroscopically complete resection was achieved in 23 of 24 procedures (95.8 %). Complications included three intraventricular hemorrhages, four memory deficits (two of them transient), one case of temporary potomania, two soft tissue infections, and one meningitis. There were no statistically significant differences between the route of resection and number of complications. The Glasgow Outcome Scale at 1 year after surgery was 5 in 82.6 % of the patients. A transventricular endoscopic approach allows macroscopically complete resection of third ventricle colloid cysts in most cases. The option of opening the choroidal fissure (transventricular–transchoroidal approach) during the procedure can address third ventricle colloid cysts that do not emerge sufficiently through the foramen of Monro without increasing procedure-related morbidity.     

Paramedian supracerebellar transtentorial approach for a medial tentorial meningioma with supratentorial extension: technical case report

OBJECTIVE AND IMPORTANCE: The choice of surgical approach to treat medial tentorial meningiomas is crucial and sometimes difficult to make. Although the subtemporal approach is most commonly used for lesions that extend mostly supratentorially, it risks injury to the vein of Labbé or the veins coursing along the subtemporal surface. To avoid venous injury, a medial tentorial meningioma was removed transtentorially through the infratentorial space via the paramedian supracerebellar transtentorial (PSCTT) approach. CLINICAL PRESENTATION: A 35-year-old right-handed woman presented with a generalized convulsion. Magnetic resonance imaging scans revealed a left medial tentorial meningioma with supratentorial extension at the dominant hemisphere. The main venous drainage route from the ipsilateral temporal lobe was a sphenopetrosal vein. INTERVENTION: An operation was performed with the patient in a sitting position, and the tumor was resected totally via the paramedian supracerebellar transtentorial approach without perioperative complications. CONCLUSION: The paramedian supracerebellar transtentorial approach is useful for supratentorially located medial tentorial meningiomas without retraction of the temporal lobe and without damage to the vein of Labbé or the sphenopetrosal vein.     

Clipping of an aneurysm of the posterior cerebral artery via the transcortical transchoroidal-fissure approach: a case report

A 65-year-old woman suddenly developed severe headache with nausea. Computed tomographic scans revealed a diffuse subarachnoid hemorrhage with thick hematoma of the left ambient cistern. Cerebral angiogram did not show any aneurysm. On the 7th day after admission, 3D-CT angiogram showed an aneurysm of the left posterior cerebral artery. On the 14th day, axial and coronal magnetic resonance images showed the aneurysm, surrounding structures and the choroidal fissure. On the 26th day after admission, successful neck clipping was performed through the temporal horn via the inferior temporal gyrus. The postoperative course was uneventful except for transient aphasia. This approach may be preferable in such cases, because it protects the brain from the detrimental effects of strong temporal retraction and provides a wider working space. In our case, thin slice MRI and MRA showing the aneurysm in the ambient cistern and the choroidal fissure were useful for deciding the appropriate approach.     

Sylvian fissure arteriovenous malformations

We have operated on 16 cases of arteriovenous malformation (AVM) in and around the sylvian fissure. We call these lesions "sylvian fissure AVMs" and classify them into four subdivisions, namely, pure, lateral, medial, and deep AVMs. By others, they have been variously called AVMs of the basal ganglia, insula, anterior choroidal artery, frontal lobe, or temporal lobe. These sylvian fissure AVMs showed similar angiographic findings: the feeders in all cases were branches of the middle cerebral artery; in some cases, additional feeders from the anterior and posterior choroidal and posterior communicating arteries were present also. We describe the characteristic features of these AVMs from the anatomical and surgical points of view. The surgical results were satisfactory in 15 cases (no additional neurological deficits), and 1 patient died.     

Inferior temporal sulcus approach for amygdalohippocampectomy guided by a laser beam of stereotactic navigator

OBJECTIVE: To describe a surgical technique for a minimally invasive transcortical transventricular amygdalohippocampectomy via the inferior temporal sulcus (ITS) using a stereotactic navigator. METHODS: Seven patients with medically intractable mesial temporal lobe epilepsy underwent an amygdalohippocampectomy via the ITS. By use of a laser-guided navigation system, the epileptogenic foci of the mesial temporal lobe were resected through a small linear operative route that was made by a brain speculum inserted from the ITS to the anterolateral floor of the temporal horn in the lateral ventricle. RESULTS: All patients completed at least a 1-year follow-up (range, 14-45 mo) after surgery and had improved neuropsychological parameters as a result of the operation. All patients became seizure-free after surgery. A Humphrey visual field perimeter detected no hemianopsia. CONCLUSION: Combined with the stereotactic navigation system, the ITS approach provides the least invasive amygdalohippocampectomy that preserves optic radiation. This approach seems beneficial especially in patients in whom the epileptic lesions are limited to the anterior mesial temporal lobe.     

The posterior subtemporal keyhole approach combined with the transchoroidal approach to the ambient cistern: microsurgical anatomy and image-guided quantitative analysis

Purpose  

The aim of this study is to describe microsurgical anatomy and to quantitatively analyze exposure using the posterior subtemporal keyhole (PSK) approach combined with the transchoroidal keyhole (TCK) approach to the ambient cistern.     

"Tangential" resection of medial temporal lobe arteriovenous malformations with the orbitozygomatic approach

OBJECTIVE: Arteriovenous malformations (AVMs) of the medial temporal lobe are usually resected through subtemporal-transcortical approaches that provide a trajectory that is perpendicular to the plane of the AVM. The pterional approach is sometimes used for AVMs in the uncus and amygdala, but it is not recommended for AVMs in the hippocampal region because it provides a "tangential" approach with limited access to posterior feeding arteries and draining veins. The orbitozygomatic approach enhances exposure along this tangential trajectory and was used in a consecutive series of 10 patients to determine its advantages. METHODS: During a 5.7-year period, 43 patients underwent resection of temporal lobe AVMs, 10 of which were located in the medial temporal lobe (amygdala and uncus [Region A] or hippocampus, parahippocampus, and fusiform gyrus [Region B]). AVMs were evenly distributed by region and by hemispheric dominance and included two Spetzler-Martin Grade IV lesions. An orbitozygomatic approach was used in all cases. RESULTS: Complete resection was accomplished in nine patients, and one patient underwent multimodality management with postoperative stereotactic radiosurgery. Good outcomes (Rankin outcome score 相似文献   

Surgical approach to arteriovenous malformation of the medial temporal lobe--report of three cases.

We report three cases of arteriovenous malformation (AVM) of the medial temporal lobe and the surgical approaches used. The AVM was fed by the anterior choroidal artery (AChA) in two cases (Cases 1 and 2) and by the posterior cerebral artery in one (Case 3). The trans-Sylvian approach was first used for cerebrospinal fluid aspiration to retract the brain in all cases, and for confirming the feeding arteries to prevent premature bleeding from the AVM in Cases 1 and 2. In Case 1, a corticotomy was then made in the fusiform gyrus via the subtemporal approach to avoid the development of speech disturbance and visual field defects, while in Cases 2 and 3, a cortical incision was made in the middle temporal gyrus because visual field defects were preoperatively present. Cases 1 and 2 achieved good recoveries, but Case 3 suffered postoperative speech disturbance and died of rebleeding from a recurrent AVM fed by the AChA 22 months after the operation. This AVM was not demonstrated on the postoperative angiograms. We emphasize the usefulness of the combination of trans-Sylvian and subtemporal approaches for this lesion, because the feeding arteries are easily identified and retraction of the temporal lobe is alleviated. A corticotomy in the fusiform gyrus is also recommended to avoid the development of not only visual field defects but also aphasia.     

Combined extradural subtemporal and anterior transpetrosal approach to tumors located in the interpeduncular fossa and the upper clivus

Background

Central skull base lesions in the interpeduncular fossa and the upper clival regions can be challenging to access because of their location anterior to the brainstem. We have modified the anterior transpetrosal approach by combination with the extradural subtemporal route to increase the surgical corridor.

Methods

Thirty-seven patients underwent surgical treatment via the anterior transpetrosal approach from 2002 to 2012. The combined surgical approach was primarily applied when the tumors arose from the upper clival portion and extended to the interpeduncular fossa. The combined approach was used in seven of these patients, comprising four patients with petroclival meningiomas, one patient with sphenoclival meningiomas, one patient with trigeminal schwannoma, and one patient with an epidermoid cyst extending from the interpeduncular fossa to the prepontine cistern.

Results

The combined approach permitted excellent visualization of the interpeduncular fossa in addition to the upper clivus and the lateral aspect of the brain stem. Mobilization of the temporal lobe by the entire epidural dissection of the lateral wall of the cavernous sinus facilitates access via the subtemporal route. The transient symptom of the temporal lobe in the dominant site may be the only drawback for this combined approach, although it may disappear immediately after the surgery.

Conclusion

The present approach combines Dolenc’s approach and Kawase’s approach, providing a wide exposure to lesions of the interpeduncular fossa and the clivus.     

Surgical management of arteriovenous malformations that follow the tentorial ring

In a series of 200 intracranial arteriovenous malformations (AVMs) treated surgically, 33 malformations were situated very close to the tentorial incisura. All but one of these AVMs were totally removed. Four operative approaches were utilized in this group of patients: an interhemispheric approach for lesions of the medial hemispheres, splenium of the corpus callosum, and posterior 3rd ventricle; a subtemporal approach to the inferior and medial temporal lobe; a supracerebellar-infratentorial approach to anterodorsal cerebellum and quadrigeminal regions; and a subtemporal transtentorial exposure to the dorsolateral mesencephalon. There were no surgical deaths. Three patients had unsatisfactory outcomes. Our experience with this series indicates that deep cerebral AVMs in the region of the tentorial incisura may be safely removed if there is proper selection of operative approach and attention to surgical technique.     

Anterior thalamoperforating artery aneurysm associated with internal carotid artery occlusion: case report.

OBJECTIVE AND IMPORTANCE: We describe a rare case of a ruptured distal anterior thalamoperforating artery aneurysm associated with right internal carotid artery occlusion. CLINICAL PRESENTATION: A 59-year-old woman experienced sudden occipital headache, vomiting, and subsequent coma as a result of massive intraventricular hemorrhage. An initial angiogram revealed only an occlusion of the right internal carotid artery just distal to the posterior communicating artery. Repeat angiography 1 month later, however, revealed a saccular aneurysm at a distal anterior thalamoperforating artery in addition to the occlusion of the internal carotid artery. INTERVENTION: We approached this aneurysm through the right temporal horn after opening the ambient cistern. The aneurysm, which was located in the brain parenchyma just medial to the temporal horn, was successfully resected. CONCLUSION: This rare aneurysm probably developed as a result of hemodynamic stress on the anterior thalamoperforating artery after occlusion of the internal carotid artery and/or secondary to chronic hypertension.     

Surgical approaches to trigonal arteriovenous malformations

Only about 5% of intracranial arteriovenous malformations (AVM's) are located predominantly within the ventricular system. Between July, 1981, and February, 1986, 15 patients were treated at the authors' institution for AVM's within the ventricular trigone. The mean age of this patient population was 24 years, and two-thirds were female. Intracranial hemorrhage was by far the most frequent presenting symptom and intraventricular hemorrhage occurred in 11 cases, with multiple episodes being documented in five. Arterial supply of the malformations was quite uniform, with the lateral posterior choroidal or posterior temporal branch of the posterior cerebral artery (PCA) being the most frequent source. Venous drainage was similarly stereotypic, with predominant outflow into the galenic system in all but one patient. An interhemispheric surgical approach was used in eight patients, a middle or inferior temporal gyrus incision was performed in six, and a subtemporal route was chosen in a single patient. Operative results suggest that these lesions can be removed with reasonable safety. An interhemispheric approach is recommended if the nidus projects medially from the trigone and is observed medial to the P2-P3 junction of the PCA on angiography. A middle temporal gyrus approach is suggested if the nidus is lateral to the P2-P3 junction, even when the lesion is located in the dominant hemisphere. A subtemporal approach should be reserved for inferiorly projecting AVM's with cortical representation on the fusiform or parahippocampal gyrus in the nondominant hemisphere.     

Case of clipping of a ruptured aneurysm of the posterior cerebral artery (P2) via the transchoroidal-fissure approach

A 59-year-old female was found to be drawn in a swimming pool and transferred to our hospital. The patient was comatose on admission (Hunt & Kosnk: Grade IV). Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) with thick hematoma in the left ambient cistern. Conventional cerebral angiography and 3D-digital subtraction angiography revealed aneurysms (ANs) of the left posterior cerebral artery (P2), and bifurcation of the left internal carotid and posterior communicating arteries (IC-PC). Successful neck clipping was performed the same day through the temporal horn via the insula for ruptured P2 AN, and the non-ruptured IC-PC AN was also obliterated using a pterional approach. Postoperative course was uneventful except for initial disturbance of consciousness and aphasia. The patient was discharged with no neurological deficit 1 month after surgery. This approach may be preferable in cases involving high positioned PCA AN in the ambient cistern, particularly in the acute phase of severe SAH, as the brain is protected from the detrimental effects of strong temporal retraction and a wider working space is provided.     

White matter fiber dissection of the optic radiations of the temporal lobe and implications for surgical approaches to the temporal horn

OBJECT: The aim of this anatomical study was to define more fully the three-dimensional (3D) relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe by using the Klingler white matter fiber dissection technique. These findings were correlated with established surgical trajectories to the temporal horn. Such surgical trajectories have implications for amygdalohippocampectomy and other procedures that involve entering the temporal horn for the resection of tumors or vascular lesions. METHODS: Ten human cadaveric hemispheres were prepared with several cycles of freezing and thawing by using a modification of the method described by Klingler. Wooden spatulas were used to strip away the deeper layers of white matter progressively in a lateromedial direction, and various association, projection, and commissural fibers were demonstrated. As the dissection progressed, photographs of each progressive layer were obtained. Special attention was given to the optic radiation and to the sagittal stratum of which the optic radiation is a part. The trajectories of fibers in the optic radiation were specifically studied in relation to the lateral, medial, superior, and inferior walls of the temporal horn as well as to the superficial anatomy of the temporal lobe. In three of the hemispheres coronal sections were made so that the relationship between the optic radiation and the temporal horn could be studied more fully. In all 10 hemispheres that were dissected the following observations were made. 1) The optic radiation covered the entire lateral aspect of the temporal horn as it extends to the occipital horn. 2) The anterior tip of the temporal horn was covered by the anterior optic radiation along its lateral half. 3) The entire medial wall of the temporal horn was free from optic radiation fibers, except at the level at which these fibers arise from the lateral geniculate body to ascend over the roof of the temporal horn. 4) The superior wall of the temporal horn was covered by optic radiation fibers. 5) The entire inferior wall of the temporal horn was free from optic radiation fibers anterior to the level of the lateral geniculate body. CONCLUSIONS: Fiber dissections of the temporal lobe and horn demonstrated the complex 3D relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe. Based on the results of this study, the authors define two anatomical surgical trajectories to the temporal horn that would avoid the optic radiations. The first of these involves a transsylvian anterior medial approach and the second a pure inferior trajectory through a fusiform gyrus. Lateral approaches to the temporal horn through the superior and middle gyri, based on the authors' findings, would traverse the optic radiations.     

Transcortical transchoroidal fissure approach for ruptured distal posterior cerebral artery (P2-P3 junction) aneurysm associated with packed intraventricular hemorrhage--two case reports

A 56-year-old man with ruptured right P2-P3 junction aneurysm and a 66-year-old man with ruptured left P2-P3 junction aneurysm of the posterior cerebral artery associated with acute-stage packed intraventricular hemorrhage. The aneurysms were successfully clipped through the transcortical transchoroidal fissure approach. This approach requires less retraction of the temporal lobe, provides a wider surgical field, and the P2 segment can be easily reached. The present approach is very useful for the treatment of ruptured aneurysms at the P2-P3 junction, in particular for acute stage surgery associated with packed intraventricular hemorrhage.