Pretemporal Transcavernous Approach to Basilar Tip Aneurysms: Operative Technique and Surgical Nuances: 3-Dimensional Operative Video.

INDICATIONS CORRIDORS AND LIMITS OF EXPOSURE: This approach provides a 360° view of the anterior upper third of posterior fossa which can tackle any kind of complex basilar aneurysm. It combines the benefits of both pterional/orbitozygomatic and subtemporal approaches. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Computed tomography angiography revealed a low-lying basilar apex, so a full transcavernous approach was used. Electroencephalogram, somatosensory evoked potentials, and brainstem auditory evoked response are essential modalities to monitor during temporary clipping. ESSENTIAL STEPS OF THE PROCEDURE: Anterior clinoidectomy, dissection of cavernous sinus, and posterior clinoidectomy to expose the perforator-free zone of basilar artery proximal to the superior cerebellar artery are essential steps described in detail in the video. Analyzing the perforator anatomy around the aneurysm before putting a clip is utmost essential. PITFALLS/AVOIDANCE OF COMPLICATIONS: Clipping a basilar aneurysm using this approach requires a neurosurgeon to have a sound knowledge of the neuroanatomy as well as a skilled handset for performing clinoidectomy and cavernous sinus dissection to avoid neurovascular injury. VARIANTS AND INDICATIONS FOR THEIR USE: Pterional/orbitozygomatic (for high riding bifurcation), subtemporal (low riding bifurcation), and endovascular therapy (small aneurysm with narrow neck) are other options used for these aneurysms.

Meges of Sidon: The "Most Learned" of Surgery's Founding Fathers.

This paper aims to bring back to life an underrated, even forgotten surgeon of the late first century B.C.E., Meges of Sidon. He was an experienced surgeon of his time and was considered the most erudite Roman surgeon before Galen. He belonged to the Alexandria School of Medicine and later migrated to Rome to practice. Although most of his work did not survive, he was mentioned by notable ancient figures, such as Celsus and Galen. He excelled in various surgical specialties, not limited to neurosurgery, orthopedics, ophthalmology, and urology. Galen cited Meges in his surgical book on head injuries and cranial procedures. Meges was known to have invented a "double-edged" blade that he used to remove stones from the neck of the bladder. His treatment of anal fistulas was a reference through the Middle Ages. Celsus, a Roman encyclopedist of the first century, would later erroneously receive credit for ancient surgical innovations, such as the nonslipping cranial drill and the treatment of depressed skull fractures, even though he was not a surgeon. However, as Celsus was going over the history of surgery, he described Meges as the "most learned" of its prominent figures. Meges' neurosurgic techniques and teachings are deduced from Celsus, who shortly succeeded him, did not practice surgery, and acknowledged him as his primary source on surgical topics.

Transcavernous Approach in Vascular Neurosurgery.

The cavernous sinus is no more considered no man's land. It is a very well organized anatomic entity that can safely be navigated. It is both a route and a destination. Unlocking the cavernous sinus provides a highway that can be used to reach different vascular and tumor locations that were deemed very risky to handle.

Growth of unruptured aneurysms: A meta-analysis of natural history and endovascular studies.

The growth of unruptured intracranial aneurysms (UIAs) is a strong predictor of rupture. Clinical observations suggest that some UIAs might grow faster after endovascular treatment than untreated UIAs. There are no head-to-head comparisons of incidence rates of UIAs thus far. METHODS: We searched PubMed, Embase and Google Scholar for relevant articles from the inception of the databases to March 2020. We pooled and compared the incidence rates for the growth of aneurysms from natural history studies and endovascular treatment studies. Generalized linear models were used for confounder adjustment for the prespecified confounders age, size and location. RESULTS: Twenty-five studies (10 describing growth in natural history and 15 reporting growth after endovascular therapy) considering 6325 aneurysms were included in the meta-analysis. The median size of aneurysms was 3.7 mm in the natural history studies and 6.4 mm in endovascular treatment studies (p = 0.001). The pooled incidence rate (IR) of growth was significantly higher in endovascular treatment studies (IR 52 per 1000 person-years, with a 95% confidence interval (CI) 36-79) compared to natural history studies (IR 28 per 1000 person-years, 95% CI 17 - 46, p-value < 0.01) after adjustment for confounders. CONCLUSION: Our results suggest that the incidence rate of cerebral aneurysm growth might be higher after endovascular therapy than the incidence rates reported in natural history studies. These results should be viewed in light of the risk of bias of the individual studies and the risk of ecological bias.

Anterior perforated substance region aneurysms: review of a series treated with microsurgical technique.

Aneurysms arising from the distal carotid, proximal A1, and proximal M1 that project posteriorly and superiorly toward the anterior perforated substance (APS) are rare. Their open surgical treatment is particularly difficult due to poorly visualized origin of the aneurysm and the abundance of surrounding perforators. We sought to analyze the anatomical and clinical characteristics of APS aneurysms and discuss surgical nuances that can optimize visualization, complete neck clip obliteration, and preservation of adjacent perforators. Thirty-two patients with 36 APS aneurysms were surgically treated between November 2000 and September 2017. Patients were prospectively enrolled in a cerebral aneurysm database and their clinical, imaging, and surgical records were retrospectively reviewed. Twenty-seven aneurysms originated from the distal ICA, 7 from the proximal A1, and 2 from the proximal M1; 15 patients presented with subarachnoid hemorrhage. Careful intraoperative dissection revealed 4 aneurysms originating at the takeoff of a perforator; another 25 had at least 1 adherent perforator. All aneurysms were clipped except for one that was trapped. Postoperatively, 3 patients had radiographic infarctions in perforator territory with only 1 developing delayed clinical hemiparesis. Good outcome (modified Rankin Scale, 0-2) was achieved in 28 patients (88%). APS aneurysms present a challenging subset of aneurysms due to their complex anatomical relationship with surrounding perforators. These should be identified on preoperative imaging based on location and projection. Successful microsurgical clipping relies on optimization of the surgical view, meticulous clip reconstruction, preservation of all perforators, and electrophysiological monitoring to minimize ischemic complication.

Autologous Temporalis Subfascial Fat Graft for Skull Base Repair: A Novel Technique.

BACKGROUND: Autologous abdominal fat grafts are occasionally used in the repair of skull base exposures. This surgical procedure typically requires an additional surgical site and may have unexpected postoperative complications. OBJECTIVE: To describe an operative technique for harvesting subfascial fat from the temporal extension of the buccal fat pad for the repair of skull base defects. METHODS: We review the pertinent anatomy of the temporalis subfascial fat pad and discuss the technique used to harvest the subfascial fat component in a clinical presentation. RESULTS: A pretemporal approach was performed for clip ligation of an anterior circulation aneurysm. A standard frontotemporal incision was made with an interfascial flap to preserve the frontalis branches of the facial nerve. The subfascial fat was inspected and determined to be adequate for harvesting. Monopolar cauterization was carefully utilized to remove the fat. During closure, the graft was used to repair a pneumatized clinoid sinus and for the dural repair of the pretemporal exposure. The patient did not have any postoperative complications. CONCLUSION: Autologous temporalis subfascial fat graft is a viable and safe technique for skull base dural and sinus repair during frontotemporal approaches in select patients. This technique avoids an additional surgical procedure and potential complications that may be associated with it.

Resection of an Isolated Pituitary Stalk Epidermoid Cyst Through a Pretemporal Approach: Case Report and Review of the Literature.

BACKGROUND: Intracranial epidermoid cysts are congenital epidermal inclusion cysts derived from ectodermal origin with desquamated skin. The majority of these cysts occur in the cerebellopontine angle cistern. Epidermoid cyst of the pituitary stalk, however, is a rare location. To date, only 4 previous cases have been reported. CASE DESCRIPTION: A 63-year-old male presented to our clinic with migraine headaches, dizziness, increased thirst, increased urinary frequency, and impotence. Magnetic resonance imaging of the brain demonstrated a rim-enhancing cystic mass with diffusion restriction on diffusion-weighted imaging located within the pituitary stalk. The patient underwent a pretemporal approach with gross total resection of the cyst. The patient's postoperative course was uneventful with no new deficits and/or endocrinopathies. CONCLUSION: Epidermoid cyst of the pituitary stalk is an unusual and rare presentation. Four other cases treated via endoscopic approaches have been previously reported in the neurosurgical literature. To our knowledge this is the first case description of an infundibular epidermoid cyst pressing with isolated diabetes insipidus surgically treated via a transcranial pretemporal approach with gross total resection. The patient had a smooth and uneventful postoperative course with persistent diabetes insipidus.

Temporary Clipping of the Intracavernous Internal Carotid Artery: A Novel Technique for Proximal Control.

BACKGROUND: Securing proximal control in complex paraclinoid aneurysm surgery through traditional techniques may be challenging and risky in certain situations. Advancements of anatomical knowledge of the cavernous sinus (CS) and hemostasis have made it more accessible as a surgical option. OBJECTIVE: To describe the technique of temporary clipping of the horizontal segment of the intracavernous internal carotid artery (IC-ICA) in preparation for permanent clipping of complex paraclinoid aneurysms. METHODS: Through an extradural pretemporal approach, the lateral wall of the CS is exposed. The dura between the trochlear nerve and V1 is opened, and access is made to the horizontal segment of the IC-ICA. After circumferential dissection, the temporary clip can be introduced to the artery, and the extradural clinoidectomy can be continued under secured proximal control. RESULTS: Seven patients with complex paraclinoid aneurysms were treated between May 2013 and May 2016 by the senior author. Temporary clipping of the IC-ICA was performed in all cases. Average time to achieve proximal control was 22.6 min (22.6 ± 13.8). One patient developed transient oculomotor palsy postoperatively. There were no other complications. CONCLUSION: When the exposed clinoidal segment of the internal carotid artery does not offer sufficient proximal space for temporary clipping, the extradural approach can be extended to the horizontal portion of the IC-ICA. In our experience, this technique is a quick, reliable, and safe alternative to the classical modalities of temporary occlusion.

Continuous Interrupted Double Throw Suturing Method: A Novel Suturing Technique for Extracranial-Intracranial Bypass.

OBJECTIVE: Despite failure of the EC/IC Bypass Study Group to demonstrate effectiveness in minimizing future stroke events, superior temporal artery-medial cerebral artery (STA-MCA) bypass remains an essential treatment for complex giant intracranial aneurysms, tumors, moyamoya disease with ischemia, and atherosclerotic steno-occlusive disease with hemodynamic cerebrovascular insufficiency. The objective of this report is to describe a novel suturing technique for STA-MCA bypass that helps reduce donor-recipient anastomosis time, allowing for a well-organized systematic workflow. METHODS: Step 1 involves passing the needle of a 9-0 polypropylene suture from out-to-in on the donor vessel followed by in-to-out on the recipient vessel. Step 2: Before cutting and tying a knot as per the established method of suturing, repeat step 1 and leave the needle "parked", creating a loop that is then cut at its proximal end. Step 3: Tie knots using the jeweler's forceps. Repeat previous steps until there are enough throws to seal the bypass adequately. RESULTS: The STA-MCA bypass serves as a principal method for flow augmentation. The technique described here allows for more efficient and organized microsurgical movements reducing vessel tissue manipulation and clamp time. CONCLUSIONS: We describe a novel technique for interrupted STA-MCA bypass suturing that adds efficiency, safety, organization, and operative ease compared with the conventional method of interrupted vessel suturing.

Morphometric Comparison of the Pterional Trans-Sylvian and the Pretemporal Trans-Clinoidal Approaches to the Posterior Communicating Artery.

BACKGROUND: Posterior communicating (Pcom) aneurysms in the modern era have tended toward increased complexity and technical difficulties. The pretemporal approach is a valuable extension to the pterional approach for basilar apex aneurysms, but its advantages for Pcom aneurysms have not been previously elucidated. OBJECTIVE: To quantify characteristics of the pretemporal approach to the Pcom. METHODS: We dissected 6 cadaveric heads (12 sides) with a pretemporal transclinoidal approach and measured the following variables: (1) exposed length of internal carotid artery (ICA) proximal to the Pcom artery; (2) exposed circumference of ICA at the origin of Pcom; (3) deep working area between the optic nerve and tentorium/oculomotor nerve; (4) superficial working area; (5) exposure depth; and (6) the frontotemporal (superior posterolateral) and (7) orbito-sphenoidal (inferior anterolateral) angles of exposure. RESULTS: Compared with pterional craniotomy, the pretemporal transclinoidal approach increased the exposed length of the proximal ICA from 3.3 to 11.7 mm (P = .0001) and its circumference from 5.1 to 7.8 mm (P = .0003), allowing a 210° view of the ICA (vs 137.9°). The deep and superficial working areas also significantly widened from 53.7 to 92.4 mm2 (P = .0048) and 252.8 to 418.2 mm2 (P = .0001), respectively; the depth of the exposure was equivalent. The frontotemporal and spheno-Sylvian angles increased by 17° (P = .0006) and 10° (P = .0037), respectively. CONCLUSION: The pretemporal approach can be useful for complex Pcom aneurysms by providing easier proximal control, wider working space, improved aneurysm visualization, and more versatile clipping angles. Enhanced exposure results in a potentially higher rate of complete aneurysm obliteration and complication avoidance.

Concomitant ruptured anterior circulation and unruptured posterior circulation aneurysms: Treatment strategy and review of literature.

Basilar artery apex or bifurcation is the most common location for aneurysms arising from posterior cerebral circulation. Reports of unruptured aneurysms of the basilar bifurcation associated with ruptured anterior circulation aneurysms are rare. The presence of multiple intracranial aneurysms poses a significantly high risk to management than a single aneurysm due several factors involved. Surgical management is considered the best treatment modality for most aneurysmal types and location with quite a few limitations when applicable. Authors have conducted a literature review of anterior and posterior circulation concomitant aneurysms and report their own experience with a case of anterior communicating artery blister type aneurysmal rupture presented with the symptoms and signs of subarachnoid hemorrhage concomitant with an unruptured basilar artery bifurcation aneurysm. Moreover, the anomalous origin of thalamoperforators at the basilar apex instead of the posterior cerebral artery makes it reasonably challenging for the microsurgical clipping. Discussed is the clinical presentation, radiological studies obtained, surgical approach utilized with an adequate exposure of the entire circle of Willis as well as the critical decision making when managing these challenging cases.

Rapid M1 Hemoclips Arteriotomy Repair After Emergency Coil Embolectomy.

BACKGROUND: The vascular closure staple clips have been studied in animal models and shown to have comparable results with sutured repair when it comes to the healing process, degree of vessel narrowing, and risk of thrombosis. However, they are clearly superior when the speed of application is taken into account, and they were clinically used in many vascular repair processes. Nevertheless, their usefulness in intracranial vascular surgery has not been described. OBJECTIVE: To describe the usefulness of hemoclips in fast and efficient repair of medium-sized and large intracranial vessels. METHODS: Two female patients diagnosed with giant symptomatic cavernous sinus aneurysms were undergoing elective endovascular procedures that were complicated by the dislodgement of coils into the M1 segment of the middle cerebral artery. Both patients were treated performing M1 arteriotomies and coil embolectomy. To avoid prolonged temporary occlusion in the M1 perforator's territory, the arteriotomies were repaired using microhemoclips in less than 10 min with re-establishment of flow. RESULTS: In both patients, flow was re-established in the M1 segments. In 1 patient, the coils extended to the temporal M2 causing intimal injury and leading to diminished flow. M1 segments in both patients were patent on later angiographic studies. CONCLUSION: We describe the advantage of emergent cerebrovascular arteriotomy and embolectomy in a rapid repair process that helped avoid massive ischemic injury. We believe this technique should be added to the armamentarium of neurosurgical cerebrovascular options.

Biocompatible Amniotic Sac Implant Maintains a Scar-Free Brain Surface During Recurrent Glioma Surgery.

BACKGROUND: Dissection of brain surface adhesions during recurrent glioma surgery carries a risk of injury to cortical vessels and important surface vessels. We present our experience with the use of BioD film, a biocompatible amniotic membrane implant, to help prevent postoperative adhesions. We describe a novel method for preventing postoperative adhesions after high-grade glioma surgery using BioD film. METHODS: Amniotic sac implants were laid on the brain surface after resection of gliomas located near major surface arteries (sylvian fissure) and major veins (parasagittal convexity). Seven cases involved reoperation for tumor recurrence. RESULTS: In all 7 of the cases requiring reoperation, a new arachnoid-like surface layer was formed without any dural adhesions. The newly formed layer allowed for easy and simple dissection and mobilization of surface vessels while avoiding any trauma to the cortex. CONCLUSIONS: Amniotic sac implants have a promising role in preventing most surgical brain adhesions associated with recurrent glioma surgery, reducing the risks of cortical vessel and tissue injury.

Synchronous ipsilateral cavernous malformations of the trochlear nerve.

BACKGROUND: Cranial nerve cavernous malformations (CM) are rare benign congenital vascular anomalies, with approximately 44 preceding cases in the literature. We report the fifth case of trochlear CM, as well as the first instance of two discrete CM occurring simultaneously along the same cranial nerve. METHODS: Case report. RESULTS: A fifty-seven year-old man presented with several years of diplopia; physical examination identified a complete left trochlear nerve paralysis. MRI revealed a 1cm enhancing lesion within the left ambient cistern, and the patient underwent left pretemporal transcavernous resection. Intraoperatively, a second, discrete CM of the trochlear nerve was also discovered; wide excision of the intrinsic trochlear lesions was completed, allowing both tumors to be removed en bloc with negative margins. Pathologic analysis confirmed both to be CM of the trochlear nerve. The patient recovered with a persistent left trochlear paralysis only, and follow-up MRI was negative for residual or recurrent disease. CONCLUSION: Cranial nerve CM are rare but potentially morbid mass lesions, with the capacity to precipitate significant neuropathies. Differential diagnosis includes schwannoma and hemangioblastoma. Definitive diagnosis may not be possible preoperatively; however, resection is recommended in symptomatic patients, potentially accompanied by nerve repair.

Intraoperative Intratumoral Embolization of a Complex Recurrent Hemangiopericytoma: Technical Report and Review of the Literature.

Objective Recurrent brain tumors represent a challenge for neurosurgeons because of the extensive blood loss and the time needed for surgical resection. Only a few hemostatic agents are useful to prevent the bleeding and thus facilitate the surgical resection. Fibrin sealant can be used to achieve sealing, tissue adherence, or hemostasis when other means of hemostasis are inadequate or inappropriate. We report the feasibility and positive effects of direct intratumoral injection of fibrin sealant during resection of a recurrent hemangiopericytoma. Material and Methods The intraoperative intratumoral injection of fibrin sealant changed the tumor properties of a recurrent hemangiopericytoma of the tentorium with infra- and supratentorial extension. From a loose friable briskly bleeding tumor, this complex lesion became a nonbleeding well-demarcated soft-firm tumor that could easily be dissected off the pial surface and totally resected without extensive bleeding. Results There are several benefits of intratumoral injection of fibrin sealant in hemangiopericytomas: (1) the extensive bleeding is diminished and blood loss minimized; (2) the restriction of the surgical view by the venous oozing is diminished, making the microsurgical dissection of the tumor capsule off the pial surface easier and safer; (3) the loose consistency of the tumor becomes firmer and facilitates the manipulation of the tumor and leads to a safer resection; and (4) a shorter operating time is needed. Conclusion The use of intratumoral fibrin glue injection is a safe and useful technique that could be used for hemostasis of highly vascularized tumors to facilitate a safer resection and to reduce blood loss.

Minimizing Collateral Brain Injury Using a Protective Layer of Fibrin Glue: Technical Note.

BACKGROUND: Neurosurgical procedures expose the brain surface to a constant risk of collateral injury. We describe a technique where the brain surface is covered with a protective layer of fibrin glue and discuss its advantages. METHODS: A thin layer of fibrin glue was applied on the brain surface after its exposure in 34 patients who underwent different craniotomies for tumoral and vascular lesions. Data of 35 more patients who underwent standard microsurgical technique were collected as a control group. Cortical and pial injuries were evaluated using an intraoperative visual scale. Eventual abnormal signals at the early postoperative T2-weighted fluid-attenuated inversion recovery (T2FLAIR) magnetic resonance imaging (MRI) sequences were evaluated in oncological patients. RESULTS: Total pial injury was noted in 63% of cases where fibrin glue was not used. In cases where fibrin glue was applied, a significantly lower percentage of 26% (P < 0.01) had pial injuries. Only 9% had injuries in areas covered with fibrin glue (P < 0.0001). Early postoperative T2FLAIR MRI confirmed the differences of altered signal around the surgical field in the two populations. CONCLUSION: We propose beside an appropriate and careful microsurgical technique the possible use of fibrin glue as alternative, safe, and helpful protection during complex microsurgical dissections. Its intrinsic features allow the neurosurgeon to minimize the cortical manipulation preventing minor collateral brain injury.

"Live cadavers" for training in the management of intraoperative aneurysmal rupture.

OBJECT: Intraoperative rupture occurs in approximately 9.2% of all cranial aneurysm surgeries. This event is not merely a surgical complication, it is also a real surgical crisis that requires swift and decisive action. Neurosurgical residents may have little exposure to this event, but they may face it in their practice. Laboratory training would be invaluable for developing competency in addressing this crisis. In this study, the authors present the "live cadaver" model, which allows repetitive training under lifelike conditions for residents and other trainees to practice managing this crisis. METHODS: The authors have used the live cadaver model in 13 training courses from 2009 to 2014 to train residents and neurosurgeons in the management of intraoperative aneurysmal rupture. Twenty-three cadaveric head specimens harboring 57 artificial and 2 real aneurysms were used in these courses. Specimens were specially prepared for this technique and connected to a pump that sent artificial blood into the vessels. This setting created a lifelike situation in the cadaver that simulates live surgery in terms of bleeding, pulsation, and softness of tissue. RESULTS: A total of 203 neurosurgical residents and 89 neurosurgeons and faculty members have practiced and experienced the live cadaver model. Clipping of the aneurysm and management of an intraoperative rupture was first demonstrated by an instructor. Then, trainees worked for 20- to 30-minute sessions each, during which they practiced clipping and reconstruction techniques and managed intraoperative ruptures. Ninety-one of the participants (27 faculty members and 64 participants) completed a questionnaire to rate their personal experience with the model. Most either agreed or strongly agreed that the model was a valid simulation of the conditions of live surgery on cerebral aneurysms and represents a realistic simulation of aneurysmal clipping and intraoperative rupture. Actual performance improvement with this model will require detailed measurement for validating its effectiveness. The model lends itself to evaluation using precise performance measurements. CONCLUSIONS: The live cadaver model presents a useful simulation of the conditions of live surgery for clipping cerebral aneurysms and managing intraoperative rupture. This model provides a means of practice and promotes team management of intraoperative cerebrovascular critical events. Precise metric measurement for evaluation of training performance improvement can be applied.

Mobilization of the transcavernous oculomotor nerve during basilar aneurysm surgery: biomechanical bases for better outcome.

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Immediate results of microsurgical clipping of posterior communicating artery aneurysms using the pretemporal transclinoidal approach.

BACKGROUND: We evaluated adverse ischemic events as early surgical results of microsurgical clipping of 44 and 34 posterior communicating artery (PComA) aneurysms through the pterional transsylvian and pretemporal transclinoidal approach, respectively, between January 2007 and October 2010. METHODS: Patients undergoing PComA aneurysm clipping were divided into two groups, and their immediate surgical results were compared and analyzed. Those who underwent the pterional transsylvian approach (group A) comprised 42 patients with 44 PComA aneurysms (24 ruptured and 20 unruptured). Those who underwent the pretemporal transclinoidal approach (group B) comprised 32 patients with 34 PComA aneurysms (20 ruptured and 14 unruptured). RESULTS: The immediate postoperative total occlusion rates were 97.7% in group A and 100% in group B. The pretemporal transclinoidal approach significantly reduced the overall risk of silent and symptomatic ischemic strokes (p = 0.04) in ruptured PComA clippings and tended to lower the incidence of intraoperative aneurysm rupture (p = 0.07) as well as the overall ischemic events (p = 0.06) in a total of 78 aneurysm clippings, as compared with the pterional transsylvian approach. Although not significantly, the pretemporal transclinoidal approach also tended to have a lower incidence of intraoperative aneurysm rupture in ruptured aneurysm clippings (p = 0.11), which were mainly responsible for the symptomatic ischemia. The pretemporal transclinoidal approach had no additional advantage over the traditional pterional transsylvian approach in unruptured PComA aneurysm clippings in the present study. CONCLUSION: The pretemporal transclinoidal approach achieved better visualization of the vital neurovascular structures surrounding PComA aneurysms, which might be a key improvement in lowering the risk of intraoperative aneurysm rupture and obtaining significantly satisfactory immediate surgical results in the microsurgical clipping of PComA aneurysms, especially ruptured ones.