Orbitopterional Approach Research Articles

How I do it: The microsurgical clipping of the giant paraclinoid aneurysm using the retrograde suction decompression technique.

Paraclinoid aneurysms account for 5.4% of all intracranial aneurysms. Giant aneurysms are found in 49% of these cases. The 5-year cumulative rupture risk is 40%. Microsurgical treatment of paraclinoid aneurysms is a complex challenge that requires a personalized approach. Extradural anterior clinoidectomy and optic canal unroofing were performed in addition to orbitopterional craniotomy. Falciform ligament and distal dural ring transection provided the internal carotid artery and optic nerve mobilization. Retrograde suction decompression was used to soften the aneurysm. Clip reconstruction was performed using tandem angled fenestration and parallel clipping techniques. Orbitopterional approach with extradural anterior clinoidectomy combined with retrograde suction decompression technique is a safe and effective modality for treatment of giant paraclinoid aneurysms.

Contralateral Ventriculostomy for Intraoperative Brain Relaxation in Supratentorial Brain Tumors.

CSF drainage from the ventricular system is a popular and effective technique for intraoperative brain relaxation as it reduces ICP, enlarges extra-axial operative corridors, and slackens the brain increasing its tolerance for surgical manipulation. However, sometimes when the ventricular chambers distant from the site of pathology are tapped, there is a risk of neurological worsening due to paradoxical herniation of the brain, exemplified by the phenomenon of upward transtentorial herniation observed in posterior fossa tumors, consequent to a supratentorial ventriculostomy. Expectation of an analogous phenomenon precludes contralateral ventricular drainage in supratentorial brain tumors producing midline shift, subfalcine herniation, and resultant distension of the opposite lateral ventricles. Demonstrating the safety and efficacy of intraoperative contralateral ventricular drainage in the presence of sub-falcine herniation. Clinical and imaging information were retrospectively collected for four cases in which this technique was adopted. The first case was a large clinoidal meningioma with a midline shift and contralateral ventriculomegaly. EVD from the dilated ventricle provided optimum brain conditions for safe resection of the tumor through an orbitopterional approach. The second case required a contralateral EVD to reduce ICP intraoperatively, for a recurrent anaplastic ependymoma with severe mass effect. It reduced the venous hypertension related to raised ICP minimizing the blood loss. Contralateral EVD was utilized to enlarge the working corridor for interhemispheric approach in two cases. Contralateral ventricular drainage is a safe, effective, and convenient operative step for reducing brain turgor in the presence of sub-falcine herniation produced by large supratentorial tumors.

Immersive Surgical Anatomy of the Frontotemporal-Orbitozygomatic Approach.

The frontotemporal-orbitozygomatic (FTOZ) approach is widely used for accessing anterolateral lesions in skull base surgery. Many studies have described the technique and quantified the surgical exposure and freedom provided by the FTOZ approach. However, few studies have provided a detailed analysis of the technique and surgical landmarks using three-dimensional (3D) models. In this study, we aimed to create a collection of volumetric models (VMs) and stereoscopic media on the step-by-step surgical technique of the FTOZ approach using cadaveric dissections. The FTOZ approach was divided into eight major steps: positioning, incision of the skin, dissection of scalp flap, mobilization of the temporalis muscle, dissection of periorbita, craniotomy, drilling of basal structures, and dural opening. The MacCarty keyhole and inferior orbital fissure are major surgical landmarks that were referenced for the six bony cuts. Photogrammetry and structured light scanning were used to construct high-resolution VMs. We illustrated the two-piece FTOZ craniotomy, followed by the one-piece and three-piece FTOZ craniotomies. Stereoscopic images, videos, and VMs were produced for each step of the surgical procedure. In addition, the mini-orbitozygomatic (MOz) and orbitopterional (OPt) approaches were considered and described as possible alternatives to the FTOZ approach. Recent advances in 3D technology can be implemented in neurosurgical practice to further enhance our spatial understanding of neurovascular structures. Surgical approaches should be carefully selected and tailored according to the patient’s unique pathology and needs.

Analysis of Surgical Freedom Variation Across the Basilar Artery Bifurcation: Towards a Deeper Insight Into Approach Selection for Basilar Apex Aneurysms

The orbitozygomatic approach is generally advocated over the pterional approach for basilar apex aneurysms. However, the impact of the extensions of the pterional approach on the obtained maneuverability over multiple vascular targets (relevant to basilar apex surgery) has not been studied before. To analyze the patterns of surgical freedom change across the basilar bifurcation between the pterional, orbitopterional, and orbitozygomatic approaches. Surgical freedom was assessed for 3 vascular targets important in basilar apex aneurysm surgery (ipsilateral and contralateral P1-P2 junctions, and basilar apex), and compared between the pterional, orbitopterional, and orbitozygomatic approaches in 10 cadaveric specimens. Transitioning from the pterional to orbitopterional approach, the surgical freedom increased significantly at all 3 targets (P<.05). However, the gain in surgical freedom declined progressively from the most superficial target (60% for ipsilateral P1-P2 junction) to the deepest target (35% for contralateral P1-P2 junction). Conversely, transitioning from the orbitopterional to the orbitozygomatic approach, the gain in surgical freedom was minimal for the ipsilateral P1-P2 and basilar apex (<4%), but increased dramatically to 19% at the contralateral P1-P2 junction. The orbitopterional approach provides a remarkable increase in surgical maneuverability compared to the pterional approach for the basilar apex target and the relevant adjacent arterial targets. However, compared to the orbitopterional, the orbitozygomatic approach adds little maneuverability except for the deepest target (ie, contralateral P1-P2 junction). Therefore, the orbitozygomatic approach may be most efficacious with larger basilar apex aneurysms limiting the control over of the contralateral P1 PCA.

Comprehensive Anatomic Assessment of the Pterional, Orbitopterional, and Orbitozygomatic Approaches for Basilar Apex Aneurysm Clipping.

The pterional approach, along with its orbitopterional and orbitozygomatic extensions, is among the most common surgical approaches for tackling challenging aneurysms of the basilar artery apex (BAX). There is general consensus that the orbitozygomatic approach provides the best exposure for these lesions. However, there is little objective evidence to support approach selection for surgical treatment of BAX aneurysms. To compare different features regarding surgical treatment of BAX aneurysms between the pterional, orbitopterional, and orbitozygomatic approaches. The pterional, orbitopterional, and orbitozygomatic approaches were sequentially completed on 10 cadaveric specimens. The visibility of perforators, lengths of exposure, and safe clipping for major BAX branches, surgical area of exposure, and the surgical freedom for the BAX target were assessed. The orbitopterional approach provided significantly greater values than the pterional approach in all variables, except for exposure of the bilateral P1 posterior cerebral artery (PCA) perforators. When compared to the orbitopterional approach, the orbitozygomatic approach did not provide a statistically significant increase in (1) surgical freedom through the carotid-oculomotor triangle, (2) area of exposure, (3) ipsilateral, and (4) contralateral P1 PCA perforator visibility, and (5) ipsilateral PCA exposure and (6) clipping lengths. The orbitopterional approach provides significantly greater surgical exposure to BAX than the pterional approach. The orbitopterional approach is less invasive while providing similar surgical access to the BAX compared to the orbitozygomatic. The results of this study show that the orbitopterional approach may be optimal for the treatment of most BAX aneurysms, particularly to reduce morbidity resulting from the full orbitozygomatic approach.

Orbitopterional Craniotomy Resection of Pediatric Suprasellar Craniopharyngioma.

The orbitopterional approach provides an excellent combination of basal access and suprasellar access. This approach also allows for less brain retraction when resecting larger suprasellar tumors that are more superiorly projecting due to a more frontal and inferior trajectory. In this operative video, the authors thoroughly detail an orbitopterional craniotomy utilizing a one-piece modified orbitozygomatic technique. This technique involves opening the craniotomy through a standard pterional incision. The craniotomy is performed using the standard three burr holes of a pterional approach; however, the osteotomy is extended anteriorly through the frontal process of the zygomatic bone as well as through the supraorbital rim. In this operative video atlas, the authors illustrate the operative anatomy, as well as surgical strategy and techniques to resect a large suprasellar craniopharyngioma in a 4-year-old male. Other reasonable approach options for a lesion of this size would include a standard pterional approach, a supraorbital approach, or expanded endoscopic transsphenoidal approach. The lesion was quite high and thus, the supraorbital approach may confine access to the superior portion of the tumor. While recognizing that some groups may have chosen the endoscopic expanded transsphenoidal approach for this lesion, the authors describe more confidence in achieving the goal of a safe and maximal resection with the orbitopterional approach. The link to the video can be found at: https://youtu.be/eznsK16BzR8 .

Orbitopterional Approach with Extradural Clinoidectomy for the Resection of a Tuberculum Sellae Meningioma: Adapting the Strategy to the Microsurgical and Pathological Anatomy.

Objectives To describe the orbitopterional approach with extradural clinoidectomy for the resection of a tuberculum sellae meningioma, with an emphasis on the microsurgical and pathological anatomy of such lesions. Design After completing the orbitopterional craniotomy in one piece, the optic nerve is identified extradurally, unroofed, and the clinoid process resected. The falciform ligament is divided and the optic nerve is decompressed extradurally. Opening the frontotemporal dura exposes the tumor in the subfrontal region. The tumor is followed along the ipsilateral and contralateral optic nerves, and its dural tail is cut and coagulated at the level of the tuberculum. Care is taken to preserve the optic nerve perforators during the dissection. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The surgery was performed by the senior author assisted by Dr. Jaafar Basma, neurosurgery fourth-year resident. The video was edited by Dr. Vincent Nguyen, neurosurgery third-year resident. Outcome Measures Outcome was assessed with the extent of resection and visual symptoms. Results A near-total resection of the tumor was achieved. A small part of tumor significantly adherent to the optic nerve was intentionally left behind. The patient had a stable vision examination postoperatively. Conclusions Understanding the microsurgical anatomy of the suprasellar region and the pathological anatomy of the tuberculum sellae meningioma is necessary to achieve a good resection of these tumors while preserving functionality of the optic apparatus. The orbitopterional approach with anterior clinoidectomy provides the appropriate access for such endeavor. The link to the video can be found at: https://youtu.be/WtAP8uqSW0M .

Orbitopterional Approach for the Resection of a Suprasellar Craniopharyngioma: Adapting the Strategy to the Microsurgical and Pathologic Anatomy.

Objectives To describe the orbitopterional approach for the resection of a suprasellar craniopharyngioma with emphasis on the microsurgical and pathological anatomy of such lesions. Design After completing the orbitopterional craniotomy in one piece including a supraorbital ridge osteotomy, the Sylvian fissure was split in a distal to proximal direction. The ipsilateral optic nerve and internal carotid artery were identified. Establishing a corridor to the tumor through both the opticocarotid and optic cisterns allowed for a wide angle of attack. Using both corridors, a microsurgical gross total resection was achieved. A radical resection required transection of the stalk at the level of the hypothalamus. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Understanding the cisternal and topographic relationships of the optic nerve, optic chiasm, and internal carotid artery is critical to achieving gross total resection while preserving normal anatomy. Participants The surgery was performed by the senior author assisted by Dr. Jaafar Basma. The video was edited by Dr. Vincent Nguyen. Outcome Measures Outcome was assessed with extent of resection and postoperative visual function. Results A gross total resection of the tumor was achieved. The patient had resolution of her bitemporal hemianopsia. She had diabetes insipidus with normal anterior pituitary function. Conclusions Understanding the microsurgical anatomy of the suprasellar region and the pathological anatomy of craniopharyngiomas is necessary to achieve a good resection of these tumors. The orbitopterional approach provides the appropriate access for such endeavor. The link to the video can be found at: https://youtu.be/Be6dtYIGqfs .

Tuberculum Meningioma: Orbitopterional Approach.

This is a case of an extensive tuberculum sella meningioma involving the circle of Willis down to the basilar artery that presented with bilateral visual loss worse on the right than left side. A one-piece right orbitopterional approach along the worse eye was used to gain access to the three cranial fossae. The orbitotomy facilitates access to the midline structures and contralateral base of the tumor with minimal brain retraction. Tumor resection is initiated by first identifying the tumor capsule, followed by piecemeal debulking via ultrasonic aspiration. Early decompression of the ipsilateral optic nerve was performed. Gross total resection of the tumor was achieved through multiple windows as follows: prechiasmatic, opticocarotid, and carotid oculomotor. Sharp dissection is performed around critical neurovascular structures to reduce strain and vascular injury. The circle of Willis including the small perforators was completely preserved. Postoperative examination at follow-up demonstrated improvement in vision less on the right side and resolution of postoperative partial third nerve palsy. The link to the video can be found at: https://youtu.be/XfEh8CjkvA0 .

From above or below: The controversy and historical evolution of tuberculum sellae meningioma resection from open to endoscopic skull base approaches

In the early 20th century, the first successful surgical removal of a tuberculum sellae meningioma (TSM) was performed and described by Harvey Cushing. It soon became recognized that TSM pose a formidable challenge for skull base surgeons because of their deep and sensitive location, proximity to critical neurovascular elements, and often dense and fibrous nature. Because of this, over the next several decades controversy transpired regarding their optimal method of resection. Early attempts involved utilization of open transcranial routes. This included classic bilateral and unilateral frontal approaches, followed by pterional or frontotemporal approaches, which have evolved to incorporate skull base modifications, such as the supraorbital, orbitozygomatic, and orbitopterional approaches. Minimally invasive supraorbital keyhole approaches through eyebrow incisions have also been adopted. Over the past 25years, the microsurgical transsphenoidal approach, classically used for pituitary and parasellar tumors, was modified to resect suprasesllar TSM via the extended transsphenoidal approach. More recently, with the evolution of endoscopic techniques, resection of TSM has been achieved using purely endoscopic endonasal transplanum transtuberculum approaches. Although each of these techniques has been successfully described for the treatment of TSM, the question still remains: is it better to access and operate on these lesions via a traditional, transcranial avenue, or are they better treated via endoscopic endonasal techniques? We outline the surgical management of TSM through history, from early transcranial and transsphenoidal approaches to modern extended endoscopic endonasal procedures. We briefly explore the arguments favoring each of the methods and the advancements which have emerged to further optimize surgical resection.

Combined Subgaleal/Myocutaneous Technique for Temporalis Muscle Dissection

Background The frontal branch of the facial nerve (FBFN) is the most susceptible neural structure to injury during frontotemporal craniotomies. The balance between adequate temporalis muscle mobilization and frontal branch protection with minimal anatomical alteration is the philosophy behind our approach to temporalis muscle dissection. Objective To describe a combined subgaleal/myocutaneous technique for dissection and mobilization of the temporalis muscle in anterolateral cranial approaches. Methods Interdisciplinary literature review of the anatomical course of the FBFN was performed. Retrospective analysis of anterolateral craniotomies performed at our institution in which the combined subgaleal/myocutaneous (CSGMC) technique was performed. Results A total of 71 cases of anterolateral craniotomies (excluding full variant orbitozygomatic) were performed with the successful application of a CSGMC technique (36 pterional, 31 orbitopterional, and 4 fronto-orbital). Partial frontalis weakness was transient in one case. Conclusion The CSGMC technique provides sufficient protection for the FBFN and allows for adequate mobilization for a variety of skull base exposures while minimally violating myofascial anatomy. This is the first reported technique that allows both adequate temporalis muscle mobilization with performance of the one-piece orbitofrontal and orbitopterional approaches, without disruption of the superficial/deep temporalis fascia and fat-pad complex.

Unilateral craniotomy for bilateral cerebral aneurysms

Multiple intracranial aneurysms located bilaterally in the anterior circulation are usually clipped sequentially by separate craniotomies or a bilateral craniotomy. However, in selected patients, bilateral aneurysms can be clipped on both sides in a single sitting through a unilateral approach and unilateral craniotomy without causing morbidity. We present our technique and results of bilateral aneurysms clipped through a unilateral craniotomy from the ruptured aneurysm side. Ten patients (between 2006 and 2008) aged 20 years to 67 years with bilateral supratentorial anterior circulation saccular aneurysms, World Federation of Neurological Surgeons Scale (WFNS) score subarachnoid hemorrhage (SAH) grades 1 and 3, Fisher grades 2 and 3, were operated with unilateral orbito–pterional craniotomy and clipping of bilateral aneurysms. A total of 23 aneurysms, 12 located contralaterally, were successfully clipped with a good outcome in nine patients and no mortality at all. We therefore conclude that the unilateral orbito–pterional approach can be safely employed in selected patients harboring bilateral supratentorial saccular aneurysms and presenting with SAH, having WFNS grade 1 to 3, Fisher grade up to grade 3. The brain must be lax intra-operatively. Wide opening of the basal cisterns, 3rd ventriculostomy, and clipping of ruptured aneurysms are the important steps to be performed first before clipping the contralateral aneurysm thus avoiding a second craniotomy.

The Orbitopterional Approach for Large and Giant Middle Cerebral Artery Aneurysms: A Report of Two Cases and Literature Review

We report two cases of complex middle cerebral artery aneurysms that were surgically treated using the orbitopterional approach in a two-piece method. The objective of this work is to discuss the usefulness of the orbitopterional approach in the surgical management of large and giant middle cerebral artery aneurysms. A 32-year-old man with a giant aneurysm and a 50-year-old woman with a large and complex aneurysm presented with subarachnoid hemorrhages. Both aneurysms were successfully clipped through an orbitopterional approach. This approach permits a more basal view of the vascular structures with only a minor retraction of frontal lobe. It also increases the view angle and amount of working space available. This approach should be considered as an alternative to the classic pterional craniotomy for the surgical management of such complex lesions.

De Novo Formation of Orbital Cavernous Malformation 9 Years After Surgical Management of Dural Arteriovenous Fistula in the Anterior Middle Fossa -Case Report-

A 30-year-old man presented with recurrent dural arteriovenous fistula (dAVF) associated with de novo orbital cavernous malformation (CM), manifesting as progressive left visual disturbance. He had undergone transarterial embolization and subsequent surgical management for a left anterior middle fossa dAVF 9 years previously. External carotid angiography showed recurrence of the dAVF. Magnetic resonance imaging revealed a well delineated intraorbital mass lesion with hypointense signal rim by T(2)-weighted imaging, adjacent to the shunting point of the recurrent dAVF. Transcranial subtotal removal of the intraorbital mass lesion through the orbitopterional approach revealed continuity between the mass lesion and the draining vein of the recurrent dAVF. The histological diagnosis was CM. His symptom was relieved postoperatively, and no regrowth was seen during the follow-up period of one year. The coexistence of recurrent dAVF with newly formed orbital CM is extremely rare, but may indicate the underlying mechanism of the formation of CMs and recurrent dAVF.

Anterior Communicating Artery Aneurysm Surgery through the Orbitopterional Approach: Long-Term Follow-Up in a Series of 75 Consecutive Patients

In this retrospective review of prospectively collected data, we report outcomes for patients with anterior communicating artery (ACoA) aneurysms treated via the orbitopterional approach and discuss the potential impact in patient outcomes by the reduction of surgery-induced brain damage. We retrospectively reviewed prospectively collected data from 40 men and 35 women (mean age, 50.8 years) who underwent clipping of ACoA aneurysms through the orbitopterional approach. Overall outcomes at discharge using the modified Rankin Scale were good in 52 (69.4%) patients, fair in 13 (17.3%), and poor in 10 (13.3%). At last follow-up, outcomes were good in 63 (84%) patients, fair in 6 (8%), and poor in 6 (8%). Disability included none in 53.6% patients, mild in 10%, partial in 18.8%, moderate in 8.6%, moderately severe in 1.4%, severe in 2.9%, extremely severe in 2.9%, and vegetative state in 1.4%. Overall, 74% of patients returned to work after 4 months, 83% of previously unemployed patients returned to baseline, and 25% were disabled. Complications were more frequent and severe after subarachnoid hemorrhage. Long-term follow-up data present the orbitopterional approach as an attractive alternative for ACoA aneurysm surgery given the low rates of surgery-related morbidity and good patient outcomes and functionality.

Commentary “Anterior Communicating Artery Aneurysm Surgery through the Orbitopterional Approach: Long-Term Follow-Up in a Series of 75 Consecutive Patients”

Commentary “Anterior Communicating Artery Aneurysm Surgery through the Orbitopterional Approach: Long-Term Follow-Up in a Series of 75 Consecutive Patients”

Cavernous hemangioma extending to extracranial, intracranial, and orbital regions

Extraaxial cavernous hemangiomas are rare intracranial lesions that can be located in different cranial compartments. Extension across different tissue planes such as the subcutaneous tissue, skull, orbital cavity, intracranial dura mater, and extracranial trigeminal divisions within the same patient has not been previously reported. This 32-year-old woman suffered left exophthalmos, left sixth nerve palsy, and trigeminal neuropathy. Magnetic resonance imaging studies revealed an extensive multicompartmental lesion, with enhancement following Gd administration. A left orbitopterional approach allowed removal of several cavernomatous lesions located in the orbit, frontotemporal dura, and lateral wall of the cavernous sinus. A histologically based diagnosis of extraaxial cavernous hemangioma was made. In the postoperative period the patient experienced a regression of her symptoms. The authors report on a case of cavernous hemangioma with a unique extension to different intracranial/extracranial compartments. Although radical removal of the lesion was not feasible, partial excision allowed for satisfactory clinical control of the patient's symptoms.

Anatomic and Clinical Study of the Orbitopterional Approach to Anterior Communicating Artery Aneurysms: In Reply

Anatomic and Clinical Study of the Orbitopterional Approach to Anterior Communicating Artery Aneurysms: In Reply

Anatomic and Clinical Study of the Orbitopterional Approach to Anterior Communicating Artery Aneurysms

Abstract OBJECTIVE To evaluate the orbitopterional approach to anterior communicating artery (AComA) aneurysms, on the basis of the quantification of this surgical exposure, compared with the pterional approach, in a cadaveric study and a retrospective review of data for 40 patients who underwent clipping of AComA aneurysms via the orbitopterional approach. METHODS In an anatomic study, four cadaveric heads underwent pterional craniotomies on the left side and orbitopterional craniotomies on the right side. A fifth head was initially subjected to bilateral pterional craniotomies and then underwent bilateral orbital osteotomies, for direct comparison of these approaches. Using frameless stereotaxy, we quantified the angles of exposure and surgical field depths provided by the pterional and orbitopterional craniotomies. In a clinical study, 40 patients who underwent clipping of AComA aneurysms via orbitopterional approaches were evaluated for basal brain injury, the need for resection of the gyrus rectus, dissection of the sylvian fissure, and approach-related complications. The incidence of postoperative hydrocephalus among patients with subarachnoid hemorrhage who underwent lamina terminalis fenestration was also reviewed. RESULTS The angles of observation were increased 46% in the axial plane (orbitopterional, 72.92 ± 6.57 degrees; pterional, 49.75 ± 2.27 degrees; P&amp;lt; 0.01) and 137.5% in the projection plane (orbitopterional, 8 ± 2.19 degrees; pterional, 19 ± 1.78 degrees; P&amp;lt; 0.01). The surgical window depth was decreased 13% with the orbitopterional approach (P&amp;lt; 0.05). Clinically, there was no incidence of frontobasal hypodensities on postoperative computed tomographic scans. Three patients (7.5%) required resection of the gyrus rectus. No patient required sylvian fissure dissection for aneurysm exposure. Two of 29 patients (6.9%) who survived subarachnoid hemorrhage required ventriculoperitoneal shunts despite lamina terminalis fenestration. No approach-related complications were recognized. CONCLUSION The orbitopterional approach improved the observation of the AComA complex and seemed to decrease the risk of intraoperative brain damage.

Anatomic and Clinical Study of the Orbitopterional Approach to Anterior Communicating Artery Aneurysms

To evaluate the orbitopterional approach to anterior communicating artery (AComA) aneurysms, on the basis of the quantification of this surgical exposure, compared with the pterional approach, in a cadaveric study and a retrospective review of data for 40 patients who underwent clipping of AComA aneurysms via the orbitopterional approach. In an anatomic study, four cadaveric heads underwent pterional craniotomies on the left side and orbitopterional craniotomies on the right side. A fifth head was initially subjected to bilateral pterional craniotomies and then underwent bilateral orbital osteotomies, for direct comparison of these approaches. Using frameless stereotaxy, we quantified the angles of exposure and surgical field depths provided by the pterional and orbitopterional craniotomies. In a clinical study, 40 patients who underwent clipping of AComA aneurysms via orbitopterional approaches were evaluated for basal brain injury, the need for resection of the gyrus rectus, dissection of the sylvian fissure, and approach-related complications. The incidence of postoperative hydrocephalus among patients with subarachnoid hemorrhage who underwent lamina terminalis fenestration was also reviewed. The angles of observation were increased 46% in the axial plane (orbitopterional, 72.92 +/- 6.57 degrees; pterional, 49.75 +/- 2.27 degrees; P < 0.01) and 137.5% in the projection plane (orbitopterional, 8 +/- 2.19 degrees; pterional, 19 +/- 1.78 degrees; P < 0.01). The surgical window depth was decreased 13% with the orbitopterional approach (P < 0.05). Clinically, there was no incidence of frontobasal hypodensities on postoperative computed tomographic scans. Three patients (7.5%) required resection of the gyrus rectus. No patient required sylvian fissure dissection for aneurysm exposure. Two of 29 patients (6.9%) who survived subarachnoid hemorrhage required ventriculoperitoneal shunts despite lamina terminalis fenestration. No approach-related complications were recognized. The orbitopterional approach improved the observation of the AComA complex and seemed to decrease the risk of intraoperative brain damage.