Transcavernous Approach Research Articles

Mobilization of the Transcavernous Oculomotor Nerve During Basilar Aneurysm Surgery

The transcavernous approach adds a significant exposure advantage in basilar aneurysm surgery. However, one of its frequently reported side effects is postoperative oculomotor nerve palsy. To present the technique of mobilizing the oculomotor nerve throughout its intracranial course and to analyze its consequences on the nerve tension and clinical outcome. The oculomotor nerve is mobilized from its mesencephalic origin to the superior orbital fissure. Its degree of mobility, related to the imposed pulling force, was measured in 11 cadaveric nerves. Tension was mathematically deduced and compared before and after mobilizing of the cavernous segment. One hundred four patients treated for basilar aneurysms with the orbitozygomatic pretemporal transcavernous approach were followed up for a 1-year period and evaluated for postoperative oculomotor nerve palsy. Releasing the transcavernous segment compared to cisternal mobilization alone resulted in a significant increase in freedom of mobility from 4 to 7.9 mm (P < .001) and in a significant decrease in tension from 0.8 to 0.5 N (P = .006). Ninety-nine percent of aneurysms treated with this technique were amenable to neck clipping, and a total of 84% of patients had a good postoperative outcome (modified Rankin Scale score, 0-2). All patients showed direct postoperative palsy; however, 97% had a complete recovery by 9 months. Only 3 patients had a persistent diplopia on medial gaze, which was corrected with prism glasses. Mobilization of the transcavernous oculomotor nerve results in better maneuverability and less tension on the nerve, which lead to successful surgical treatment and favorable oculomotor outcome.

Pretemporal Transcavernous Approach for Microsurgical Clipping of Giant, Embolized, and Lower Basilar Tip Aneurysms

Pretemporal Transcavernous Approach for Microsurgical Clipping of Giant, Embolized, and Lower Basilar Tip Aneurysms

Posterior clinoid process as a landmarker in current endoscopic-assisted neurosurgical approaches

Summary Background/Introduction The morphologic variations of posterior clinoid process (PCP) anatomy have rarely been documented in the neurosurgical literature. Purpose(s)/Aim(s) We investigated the PCP in terms of the endoscopic perspective, which will guide surgeons for safely maneuvering within the paraclinoid region and during the transcavernous approach. Methods Four alcohol-immersed cadaveric heads injected with pigmented silicone rubber were prepared for skull base dissections. We evaluated the three-dimensional reconstructed anatomy of PCPs. Bilateral pterional and endonasal transclival approaches were performed. In pterional corridors, we advanced the dissection through the optic-carotid triangle to observe the PCP; whereas in transclival approaches, we applied a transclival route to expose the dorsum sellae and PCP. Two angled (0 and 30°) rigid endoscopes with outer diameters of 4 mm were introduced. By endoscopically viewing the surgical anatomy, the PCP and dorsum sellae were seen with ease in both approaches. Results All of the specimens showed an intact dorsum sellae and both posterior clinoid processes. Morphologic variation was described and recorded in each specimen. The posterior clinoid process is a landmark in important neurosurgical approaches. In our study we described the spatial guidance in either transcranial or transnasal endoscopic routes. Conclusion Taking advantage of the innovative integration of the video processing system, it facilitates the surgeons to work in a limited confined intracranial space. We are convinced that it provides practical information concerning the trans-PCP maneuver.

Extradural Transcavernous Approach to Cavernous Sinus Hemangiomas: Series of 12 Cases

Extradural Transcavernous Approach to Cavernous Sinus Hemangiomas: Series of 12 Cases

Endoscope-Assisted Microsurgical Removal of an Epidermoid Tumor within the Cavernous Sinus

Epidermoid tumor of the cavernous sinus is rare. The aim of this case report is to discuss the role of neuroendoscopes in the removal of such lesions. A 21-year-old man presented with 6-year history of progressive headache, diplopia, and visual disturbance. Work-up revealed an epidermoid tumor located in the right cavernous sinus. An extradural transcavernous approach was utilized via a traditional frontotemporal craniotomy with endoscopic assistance. The postoperative course was uneventful with immediate improvement of the patient's headache. Postoperative magnetic resonance imaging demonstrated complete removal of the tumor. There were no signs of recurrence during a 2-year follow-up period. The endoscope is a useful tool for removing epidermoid tumors from the cavernous sinus and enhances visualization of areas that would otherwise be difficult to visualize with microscopes alone. Endoscopes also help minimize the retraction of neurovascular structures.

Accessing the Basilar Artery Apex: Is the Temporopolar Transcavernous Route an Anatomically Advantageous Alternative?

The restricted operative field, difficulty of obtaining proximal vascular control, and close relationship to important anatomic structures limit approaches to basilar apex aneurysms. We used a cadaveric model to compare three surgical transcavernous routes to the basilar apex in the neutral configuration. Five cadaveric heads were dissected and analyzed. Working areas and length of exposure provided by the transcavernous (TC) approach via pterional, orbitozygomatic, and temporopolar (TP) routes were measured along with assessment of anatomic variation for the basilar apex region. In the pterional TC and orbitozygomatic TC approaches, the mean length of exposure of the basilar artery measured 6.9 and 7.2 mm, respectively (p = NS). The mean length of exposure in a TP TC approach increased to 9.3 mm (p < 0.05). Compared with the pterional and orbitozygomatic approaches, the TP TC approach provided a larger peribasilar area of exposure ipsilaterally and contralaterally (p < 0.05). The multiplanar working area related to the TP TC approach was 77.7 and 69.5% wider than for the pterional TC and orbitozygomatic TC, respectively. For a basilar apex in the neutral position, the TP TC approach may be advantageous, providing a wider working area for the basilar apex region, improving maneuverability for clip application, fine visualization of perforators, and better proximal control.

Nuances and technique of the pretemporal transcavernous approach to treat low-lying basilar artery aneurysms

Basilar artery bifurcation aneurysms (BAAs) constitute a major surgical challenge, due to the depth of the target anatomy and narrowness of field, the close relationship with thalamoperforating arteries, and difficulty in obtaining proximal control. Moreover, to treat these aneurysms may be especially technically demanding when situated in a low-lying basilar apex configuration. The most used approaches to treat BAA are the subtemporal approach and the pterional approach. The advantages and disadvantages of these techniques are very well known. Variations of these approaches were created attempting to overcome the limitations imposed by the limited deep operative area. They have not been able to improve the working space in the depths of the interpeduncular and prepontine cisterns. The transcavernous approach was devised as a means of enlarging the area of exposure around the interpeduncular and prepontine cisterns. It involves the removal of the anterior clinoid process, cutting distal and proximal dural rings, opening the cavernous sinus, and drilling varied extension of dorsum sellae and clivus. The senior author (EdO) has used a pretemporal approach to deal with BAAs. The authors have added a transcavernous approach in a pretemporal perspective to treat low-lying, complex, or giant basilar artery aneurysms. In this paper, the authors detail its anatomical principles and technical nuances and present the clinical experience with using this technique.

Tempozygomatic Transcavernous Approach for Nonfunctional Giant Parasellar Pituitary Adenoma

Background: A parasellar nonfunctional giant invasive pituitary adenoma is still a big challenge for surgical removal because of its intimacy with vital structures and severe postoperative complications resulting from injury of the hypothalamus and middle cerebral artery. High morbidity and mortality has been reported.

Surgical, Radiological, and Endocrinological Cure in Either Hormonally Active or Nonfunctional Invasive Pituitary Adenomas with Radical Surgical Removal

Introduction: Giant and invasive pituitary adenomas comprise up to 5% of all pituitary adenomas. Most of these are aggressive in clinical course, with cavernous sinus invasion. Traditionally, these invasive adenomas are resected with trans-sphenoidal approaches and followed by irradiation for the residuals. However, high recurrence and complication rates are described in the literature, especially for younger patients. Based on this, we used epidural transcavernous approaches to cure locally infiltrative cavernous sinus and to avoid the risks of irradiation therapy.

Long-Term Outcome of Microsurgical Treatment of Symptomatic Cavernous Sinus Meningiomas

Objective: Most cavernous sinus meningiomas (CSMs) not only cause severe cranial nerve (CN) neuropathy, but also carry the high risk of occluding the internal carotid artery. The treatments for CSM are difficult and still controversial. We report our experience with the pretemporal transcavernous approach for resection of CSMs.

Advances in Open Neurovascular Surgery 2007

We have read with great interest the Advances in Stroke 2007 subsection in February’s issue of Stroke and congratulate Dr Fisher for nicely amalgamating articles addressing some of the most pressing advances and shortcomings in stroke management over the past year.1 Although advances in interventional approaches to stroke and neurovascular disease were nicely outlined,1,2 we noticed little emphasis on open neurosurgical approaches. Of particular interest to our cerebrovascular team, reviewing the success of hemicraniectomy for malignant middle cerebral artery infarction1,3 served to support the evidence that we have observed at our institution for this successful intervention for an oftentimes devastating disease. We would, however, like to further highlight more of the exciting advances in open cerebrovascular neurosurgery that have emerged over the past year for stroke and neurovascular diseases. As already acknowledged in your Advances in Stroke 2007 subsection,2 the results of the International Study of Unruptured Intracranial Aneurysms (ISUIA) continued to meet with considerable scrutiny over the past year. Promisingly, advances in both endovascular and neurosurgical approaches to aneurysm treatment continued in 2007. Kassam et al reported the first endoscopic endonasal clipping of a superior hypophyseal aneurysm.4 Kim et al presented a novel approach to the management of fusiform aneurysms, circumferentially cinching a Gore-Tex sling against an already clip-reconstructed parent vessel by clipping the free ends of the sling immediately adjacent to the vessel.5 Krisht et al presented their impressive experience with 50 complex basilar aneurysms managed through a pretemporal, transzygomatic transcavernous approach.6 These aneurysms, unamenable to endovascular coiling, were successfully clipped in 98% of cases with no procedure-related mortality and 6-month follow-up Rankin scores of 0 to 2 in 92% of patients. Given that half of the patients in this series presented …

Posterior Clinoidectomy: Dural Tailoring Technique and Clinical Application

The posterior clinoid process, a bony prominence at the superolateral aspect of the dorsum sellae, has a strategic importance in a transcavernous approach to basilar tip aneurysms. To further optimize this microsurgical technique during posterior clinoidectomy, we performed a cadaveric study of this regional anatomy, describe a technique called dural tailoring, and report initial results in the surgical treatment of upper basilar artery (BA) aneurysm. After 10 adult cadaver heads (silicone-injected) were prepared for dissection, a posterior clinoidectomy with dural tailoring was performed. The dura overlying the upper clivus was coagulated with bipolar electrocoagulation and incised. Stripping dura off the clivus and lateral reflection then exposed the ipsilateral posterior clinoid process and dorsum sellae, thus creating a dural flap. Posterior clinoidectomy with dural tailoring was then used in seven patients with upper BA aneurysms. Our stepwise modification of the posterior clinoidectomy with dural tailoring created a flap that afforded protection of the cavernous sinus and oculomotor nerve. During surgery, there were no recorded intraoperative injuries to neurovascular structures. One patient died postoperatively from morbidity related to severe-grade subarachnoid hemorrhage. Postoperative oculomotor nerve palsy occurred in 3 patients (43%). In all cases, the nerve was anatomically preserved and partial to complete recovery was recorded during the first postoperative year. This technique effectively provided exposure of retrosellar upper basilar aneurysms in seven patients (basilar tip 43% and superior cerebellar artery aneurysms 57%). Outcomes and safety are at least equivalent to or better than basilar aneurysm surgery performed without surgical adjuncts, presumably a less complex subset.

Extradural Transcavernous Approach to Cavernous Sinus Hemangiomas: Series of 10 Cases and Review

Objective and Importance: Cavernous sinus hemangiomas (CSHs) comprise fewer than 1% of all parasellar masses. Because of their location, propensity for profuse bleeding during surgery, and relationship to complex neurovascular structures, they are notoriously difficult to excise.

Modified abbreviated transcavernous approach to basilar artery aneurysms—Case report

Background Endovascular procedures and direct surgical clipping are the main therapeutic modalities for managing of BAAs. Furthermore, giant or wide-necked aneurysms and those that involve the PCA or perforators at its neck usually are not embolized. Case Description A 55-year-old man presented to the emergency room complaining of sudden and intense headache. Neurological examination evidenced meningismus. Computed tomography disclosed a subarachnoid hemorrhage (Fisher grade III). Arteriograms revealed BAA, whose neck was partially obscured by the PCP. A standard pterional craniotomy was performed, followed by extensive drilling of the greater sphenoid wing. The neck was partially hidden by the PCP, and no proximal control was obtained without drilling the PCP and opening the CS (modified TcA). Drilling of the PCP was begun by cutting the overlying dura and extended caudally as much as possible. Next, opening of the roof of the CS was performed by incising the dura in the oculomotor trigone medial and parallel to the oculomotor nerve and lateral to ICA; the incision progressed posteriorly toward the dorsum sellae. Further resection of the dorsum sellae and clivus was carried out. After performing these steps, proximal control was obtained, aneurysm was deflated, perforators were saved, and aneurysm was clipped. Conclusions This study has demonstrated the clinical usefulness of an abbreviated form of the TcA, which led the “modified TcA,” in approaching complex low-lying BAA. It provides additional surgical room by removing the PCP and partially opening the CS, which permits further bone removal and improves exposure.

THE PERFORATOR-FREE ZONE OF THE POSTERIOR COMMUNICATING ARTERY AND ITS RELEVANCE IN APPROACHES TO THE INTERPEDUNCULAR CISTERN, ESPECIALLY THE TRANSCAVERNOUS APPROACH

Because the microsurgical working space in the interpeduncular fossa is very narrow, using different surgical approaches such as the pterional approach and/or the pretemporal transcavernous approach in combination with a division of the posterior communicating artery (PComm) at the longest perforator-free zone (PFZ) can help to enlarge the microscopic field of view and the working space in this area of the brain. In this microanatomic study, the variability of several parameters of the PComm, especially the location of the longest PFZ of the PComm, was examined and described in 23 cadaveric heads. In most cases, the mean length of the longest PFZ was found to be between 2 and 6 mm. In 80% of the cases, the longest PFZ was located closer to the posterior cerebral artery than to the internal carotid artery. A total of 82.5% of all the PComms measured were of the adult type. In 55% of all arteries, a premamillary artery was identified. When a short and adult-type PComm obscures the microscopic view of the operative field, dividing the PComm is mandatory. In other situations, dividing the PComm is facultative. Because the PComm is usually predominantly irrigated by the internal carotid artery, it is of hemodynamic advantage that the longest PFZ is typically located closest to the posterior cerebral artery. On the basis of this descriptive anatomic study, we conclude that when it is needed, division of an adult-type PComm at the longest PFZ is usually feasible and results in a low risk of compromising the blood flow to the branching perforators of the PComm.

TAMING THE CAVERNOUS SINUS

Improved understanding of the microsurgical anatomy of the cranial base region has made surgery in and through the cavernous sinus safer. However, continuous venous oozing that occurs during cavernous sinus surgery can cause significant blood loss and poor visualization. We describe a technique that will help minimize cavernous sinus bleeding and improve the safety of the surgical steps. The lateral wall of the cavernous sinus is exposed. Cavernous sinus access windows between the V1 and V2 branches of the trigeminal nerve and posterior to the clinoidal internal carotid artery are used to inject fibrin glue into the different cavernous sinus compartments. Postoperative follow-up cerebral angiography in basilar apex aneurysms clipped using the transcavernous approach were evaluated for cavernous sinus patency during the venous phase. Fibrin glue injection between V1 and V2 obliterated the lateral cavernous sinus compartment. Fibrin glue injection posterior to the clinoidal segment of the internal carotid artery obliterated the medial compartment of the cavernous sinus. These steps were used in 217 surgical procedures (95 benign and 9 malignant neoplastic lesions; 113 aneurysms). There were no significant clinical side effects. Follow-up angiographic controls of basilar aneurysms operated on via the transcavernous approach consistently showed the reestablishment of flow within the cavernous sinus as early as 2 to 3 months postoperatively. Presently, the use of hemostatic agents and the better understanding of the microsurgical anatomy of the cranial base and cavernous sinus enable us to tame the cavernous sinus and operate in and around it with a high degree of safety.

Adenomas hipofisarios con invasiòn intracavernosa: Resultados del abordaje transcraneal al seno cavernoso

Pituitary adenomas represent a significant proportion (+o-13%) of all intracranial tumors. Surgical treatment is as rule performed by transsphenoidal approach. However, a small but not insignificant subgroup of pituitary adenomas (5 to 7%) invade the lateral parasellar structures and the cavernous sinus in particular, and poses obvious problems to the therapeutic strategy, since transsphenoidal removal of these adenomas is usually incomplete. To evaluate the results of transcranial removal of a consecutive series of pituitary adenomas invading the cavernous sinus. A retrospective study of 9 patients harbouring pituitary adenomas invading the cavernous sinus who had been submitted to transcranial surgery was conducted. These patients were operated on in the time span June 1999 - December 2003, in the Nuova Clinica Latina (now NCL- Neurological Centere of Latium), Rome Italy, and the Hospital "Hermanos Ameijeiras", La Habana, Cuba, using a fronto-orbitozigomatic (FOZ) craniotomy, anterior clinoidectomy and a limited dissection of the cavernous sinus through the antero-medial triangle. Total macroscopical removal was achieved in 8 cases, partial in 1, who showed improvement or normalization of the hormonal levels and of the preoperative symptoms. Transitory complications occurred in 6 patients, one of them showed a permanet neurological deficit (paresis of the III cranail nerve). Transcranial transcavernous approach is an effective technique for attempting total removal of intracavernous pituitary adenomas. It allows to achieve remission of symptoms and hormonal control in the medium-long term. However complications are relatively frequent, and permanent sequelae are not negligible.

Anatomical and Quantitative Description of the Transcavernous Approach for Basilar Artery Aneurysms

Introduction: The management of wide-necked, giant, or unsuccessfully coiled basilar apex aneurysms requires a wide exposure, both for working area and linear visualization of the basilar artery. Cranial-based approaches, such as the transcavernous approach (TcA), have been proposed to deal with such aneurysms; whether abbreviated forms of this approach might provide similar exposure remains controversial. This study examines this issue quantitatively.

EXTRADURAL TRANSCAVERNOUS APPROACH TO CAVERNOUS SINUS HEMANGIOMAS

Cavernous sinus hemangiomas (CSHs) are uncommon lesions and comprise fewer than 1% of all parasellar masses. Because of their location, propensity for profuse bleeding during surgery, and relationship to complex neurovascular structures, they are notoriously difficult to excise. The authors describe their experience with seven cases of CSHs. Headache and visual impairment were the most common presenting complaints, followed by facial hypesthesia and diplopia. Computed tomographic scans revealed iso- to hyperdense expansile lesions in the region of the cavernous sinus and middle cranial fossa. Magnetic resonance imaging scans revealed hypo- to isointense lesions on T1-weighted images and markedly hyperintense lesions on T2-weighted images, with marked homogeneous enhancement after contrast administration. All CSHs were treated by a purely extradural transcavernous approach. This involved reduction of sphenoid ridge, exposure of the superior orbital fissure, drilling of the anterior clinoid process, coagulation and division of the middle meningeal artery, and peeling of the meningeal layer of the lateral wall of the cavernous sinus from the inner membranous layer. The cranial nerves in the lateral wall of the cavernous sinus were exposed (Cranial Nerves III and IV, as well as V1, V2, and V3). The tumor was accessed through its maximum bulge through either the lateral or anterolateral triangle. The tumor was removed via rapid decompression, coagulation of the feeder from the meningohypophyseal trunk, and dissection along the cranial nerves. All but one patient had complete tumor excision. Transient ophthalmoparesis (complete resolution in 6-8 wk) was the most common surgical complication. To our knowledge, we describe one of the largest series of pure extradural transcavernous approaches to CSHs. CSHs are uncommon but challenging cranial base lesions. The extradural transcavernous approach allows complete excision with minimal mortality or long-term morbidity.

RESULTS OF MICROSURGICAL CLIPPING OF 50 HIGH COMPLEXITY BASILAR APEX ANEURYSMS

Complex basilar aneurysms (large size, wide base, low bifurcation, and dysmorphic posteriorly projecting domes) frequently fail endovascular treatment. We report our experience using the pretemporal transzygomatic transcavernous approach with 50 complex basilar aneurysms. Using the pretemporal transcavernous route, opening the occulomotor trigone, and removing the anterior clinoid and the posterior clinoid when necessary, a wide exposure of the interpeduncular fossa is achieved. Temporary clips are applied to a perforator-free zone of the basilar trunk, proximal to the superior cerebellar artery. Complexity criteria in the 50 aneurysms included large or giant size in 27 patients, wide dysmorphic base in 18 patients, low bifurcation in 21 patients, posteriorly projecting dome in 11 patients, and dolichoectasia of the apex in three patients. Twenty-five patients presented with subarachnoid hemorrhage. There were 14 men and 36 women between the ages of 32 and 76 years (mean, 52.2 yr). Forty-nine aneurysms (98%) were successfully clipped. There was no procedure-related mortality. Two patients died (one from delayed bowel ischemia and one from a vasospasm-related complication). There were three ischemia-related events, two of which were procedure-related (medial thalamic lacunar infarct, superior cerebellar distribution ischemia) and one which was a third distal middle cerebral cardiac embolus after stopping Coumadin (DuPont Pharmaceuticals, Wilmington, DE) for atrial fibrillation. Transient partial or complete occulomotor palsies occurred in all patients with full recovery as the rule, except in one patient. At discharge, Glascow Outcome Scale scores were 4 or 5 in 88% of the patients. At the 6-month follow-up examination, Rankin Outcome Scale scores were 0 to 2 in 92% of the patients. Our experience reintroduces microsurgery as a safe and more durable treatment option for the management of complex basilar apex aneurysms that tend to have a higher rate of failure with endovascular therapy.