Comparative anatomical analysis between lateral supraorbital and minipterional approaches.

Background: The pterional craniotomy, described by Yasargil and Fox in 1975, constitutes the most traditional and important surgical access in vascular neurosurgery. Minimally invasive alternatives include the minipterional (MP) and lateral supraorbital (LSO) craniotomies, which avoid complications such as injury to the frontal branch of the facial nerve, temporal muscle dysfunction, depression of the craniotomy site, frontal sinus opening, and cosmetically unacceptable outcomes. We evaluated and compared the exposures provided by MP and LSO craniotomies through quantitative measurements of the surgical exposure area around the circle of Willis and parasellar regions, as well as angular and linear exposures of the internal carotid artery (ICA) bifurcation, middle cerebral artery (MCA), midpoint of the anterior communicating artery, and tip of the basilar artery (BA). Methods: Seven fresh cadavers were dissected at the São Paulo Medical Examiner's Office, SP, and three at the skull base laboratory of Weill Cornell Medical College, New York, USA. The craniotomies were performed sequentially, initially with the LSO craniotomy followed by the MP. After the craniotomy, the surgical exposure area, craniotomy area, and angular exposures in the horizontal and vertical axes were determined. Results: The MP craniotomy provided better angular exposure for the ipsilateral MCA, while the LSO craniotomy and BA provided better vertical axis exposures. The LSO craniotomy provided better angular exposure in the vertical axis for the midpoint of the anterior communicating artery and contralateral ICA bifurcation. Regarding surgical exposure and craniotomy area, there were no statistically significant differences. Conclusion: The MP craniotomy offers a significantly larger surgical exposure compared to the LSO craniotomy, with specific advantages regarding angular exposure to important neurovascular structures. This study provides important quantitative data to guide the choice between these minimally invasive access techniques in vascular neurosurgery.

Pear-Shaped Craniopharyngioma: Selection of the Transcranial Approach With Respect to Topographical Classifications.

We present the selection of the transcranial microsurgical approach, operative treatment, and outcomes following the resection of a pear-shaped craniopharyngioma (CP). A nine-year-old boy was operated on and followed up for 2.5 years after radical resection of the extrapial CP. Postoperatively, there was no tumor recurrence. The surgical strategy was discussed based on the preoperative MRI appearance of the CP, especially its morphological characteristics, including not only its size and shape but also its relationship with the hypothalamus, pituitary stalk/gland, ventricles, and optic chiasm, and the possible location of perforators. A description of the tumor topography is provided together with a discussion on the rationale for the selection of our surgical approach. Based on an understanding of the tumor topography, important information can be gained for approach selection, surgical planning, and anticipation of the hypothalamic-pituitary outcome.

Preservation of the middle meningeal artery during unruptured aneurysm surgery: an independent risk factor for postoperative chronic subdural hematoma.

Background: Although microsurgical clipping for unruptured aneurysms has become safer and more efficient with modern neurosurgical advances, postoperative chronic subdural hematoma (CSDH) persists as an underrecognized complication. This study investigated the association between preservation of the anterior branch of the middle meningeal artery (MMA) during surgery and CSDH development. Methods: We retrospectively reviewed 120 patients who underwent clipping for unruptured aneurysms at Kyungpook National University Chilgok Hospital between May 2020 and July 2023. We evaluated the patients on the basis of surgical approach-lateral supraorbital (LSO) or standard pterional craniotomy-and the status of the MMA postoperatively. We employed pre-and post-operative MR angiography to assess MMA preservation and used follow-up computed tomography scans to monitor CSDH development. Results: Of the 120 patients, 22 (18.3%) developed CSDH. Univariate analysis revealed that male sex, advanced age, and MMA preservation are risk factors for postoperative CSDH. Multivariate analysis supported these findings, indicating a significant association with the development of CSDH. MMA preservation was reported in 65 patients, of whom 60 and 5 underwent LSO and pterional craniotomy, respectively. Conclusion: Preservation of the anterior branch of the MMA during unruptured aneurysm surgery is a risk factor for postoperative CSDH development. Advanced age and male sex also contribute to the increased risk. These findings highlight the need for further investigation into surgical techniques that could mitigate postoperative CSDH development.

'What's in a name', a systematic review of the pterional craniotomy for aneurysm surgery and its many modifications with a proposal for simplified nomenclature.

BACKGROUND: The pterional or frontosphenotemporal craniotomy has stood the test of time and continues to be a commonly used method of managing a variety of neurosurgical pathology. Already described in the beginning of the twentieth century and perfected by Yasargil in the 1970s, it has seen many modifications. These modifications have been a normal evolution for most neurosurgeons, tailoring the craniotomy to the patients' specific anatomy and pathology. Nonetheless, an abundance of variations have appeared in the literature. METHODS: A search strategy was devised according to the 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. To identify articles investigating the variations in the pterional approach, the following search terms were applied: (pterional OR minipterional OR supraorbital) AND (approach OR craniotomy OR technique). RESULTS: In total, 3552 articles were screened with 74 articles being read in full with 47 articles being included for review. Each article was examined according the name of the technique, temporalis dissection technique, craniotomy technique and approach. CONCLUSION: This systematic review gives an overview of the different techniques and modifications to the pterional craniotomy since it was initially described. We advocate for the use of a more standardised nomenclature that focuses on the target zone to simplify the management approach to supratentorial aneurysms.

Exoscopic resection of giant olfactory groove meningioma.

Olfactory groove meningiomas represent 8%-13% of all intracranial meningiomas. Gross-total resection for large (4-6 cm) and giant (> 6 cm) cases remains challenging due to their relationship with critical neurovascular structures and extensive frontal lobe edema. A variety of transcranial and endoscopic approaches have been described. This 2D operative video shows the use of a digital 3D exoscope in the removal of a giant olfactory groove meningioma through a lateral supraorbital approach in a 57-year-old woman with visual impairment and apathy. The exoscope provides a very good angulated view of the subfrontal area on both sides of the anterior cranial fossa even through a small craniotomy. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23125.

Clip Reconstruction of Fusiform A1 Segment Aneurysm Using Lateral Supraorbital Approach.

Fusiform aneurysms of the anterior cerebral artery are a surgical rarity encountered only occasionally by a neurosurgeon.1,2 Seen most commonly in the vertebrobasilar territory, these aneurysms differ in pathophysiology and clinical presentation from their saccular counterparts. Arterial dissections and atherosclerosis are the leading causes of these aneurysms in young and elderly patients, respectively.3 Patients can present with symptoms related to mass effect/compression of adjacent structures or with ischemic symptoms apart from aneurysm rupture. Management of these aneurysms remains challenging owing to the lack of a distinct neck. Surgical options include clip reconstruction, parent vessel occlusion, or aneurysm trapping with4 and without1 bypass using a branch of the superficial temporal artery. Clipping techniques used for these aneurysms include the use of fenestrated clips, vessel wall reconstruction, and wrapping.5,6 However, due to enormous variations in aneurysm morphology, each case presents a unique challenge; hence neurosurgeons need to be aware of this important entity. Endovascular techniques including parent vessel occlusion or vessel-preserving techniques using coil or flow diverters have also been described,3 but clipping remains the preferred choice for most surgeons worldwide. In Video 1, we present a case of fusiform A1 segment aneurysm in a 34-year-old gentleman and demonstrate how the aneurysm was clipped using a lateral supraorbital approach. He made an uneventful recovery with subtle right lower limb weakness. This video shows the technique and utility of a minimally invasive skull base approach for dealing with a fusiform anterior circulation aneurysm.

Comparative cost analysis of endovascular and open approaches for elective treatment of middle cerebral artery aneurysms.

BACKGROUND: Intracranial aneurysms of the middle cerebral artery can be treated using several open surgical and endovascular approaches. Given the growing evidence of clinical equipoise between these various treatment strategies, there is a need to assess the costs associated with each. METHODS: Cost of aneurysm treatment was divided into two categories for comparison. "Initial cost" comprised the total in-hospital expenses for initial aneurysm treatment and "total cost" comprised initial aneurysm treatment and all expenses relating to readmission due to treatment-related complications, prescribed catheter angiograms for monitoring of treatment stability, and any retreatments needed for a given aneurysm. The open surgical group was subdivided into a pterional approach group and a lateral supraorbital (LSO) approach group for. RESULTS: Median initial cost was $37,152 (IQR $31,318-$44,947) for aneurysms treated with the pterional approach, $29,452 (IQR $27,779-$32,826) for aneurysms treated with the LSO approach, and $19,587 (IQR $14,125-$30,521) for aneurysms treated with endovascular approaches. The median total cost was $39,737 (IQR $33,891-$62,259) for aneurysms treated with the pterional approach, $31,785 (IQR $29,513-$41,099) for aneurysms treated with the LSO approach, and $24,578 (IQR $18,977-$34,547) for aneurysms treated with endovascular approaches. Analysis of variance test demonstrated variance across groups for both initial and total cost (p = 0.004, p = 0.008, respectively). In our subsequent analysis, initial cost and total cost were higher in the pterional group than the endovascular group (p = 0.003 and p = 0.006, respectively). CONCLUSIONS: Endovascular treatment of elective aneurysms has a significantly lower cost than open surgical treatment with the pterional approach, but not with the LSO approach. For aneurysms not amenable to endovascular treatment, a minimally invasive LSO approach carries a lower cost burden than a pterional approach.

Application of protective superficial temporal artery to middle cerebral artery bypass through the lateral supraorbital approach: Technical note.

OBJECTIVE: The lateral supraorbital (LSO) approach is a minimally invasive craniotomy widely used in the surgical treatment of intracranial aneurysms (IAs). A protective bypass is considered a safety measure in high-risk and complex clipping procedures to maintain distal cerebral flow. However, the protective bypass has so far only been applied through a pterional or larger craniotomy. We aimed to describe the characteristics of the superficial temporal artery to middle cerebral artery (STA-MCA) bypass through the LSO craniotomy to treat complex IAs. METHODS: We retrospectively identified six patients with complex IAs who underwent clipping and a protective STA-MCA bypass through the LSO approach between January 2016 and December 2020. The STA donor artery was harvested through the same curvilinear skin incision with a small extension, and it was anastomosed to the opercular segment of the MCA. Subsequently, aneurysm clipping followed standardized steps. RESULTS: Anastomosis was successful in all patients. Despite requiring temporary occlusion of the parent artery, all aneurysms were successfully clipped without any neurological deterioration. CONCLUSIONS: A protective STA-MCA bypass is feasible through the LSO approach with certain technical modifications. This technique helps protect distal cerebral flow for safe clip placement in the treatment of complex IAs with the associated benefits of a less invasive craniotomy.

A meta-analysis of Lateral supraorbital vs mini Pterional approach in the outcome of rupture and unruptured noncomplex aneurysms' surgery.

To determine the characteristics and to compare the functional outcomes and safety of different subfrontal approaches versus mini Pterional (MPT) approaches mainly for the treatment of ruptured noncomplex intracranial aneurysms. This meta-analysis included articles comparing outcomes of brain aneurysms (BAs) - most for the anterior circulation-, using Lateral supraorbital & Supraorbital keyhole (LSO) versus MPT approach. There were six articles left into the final article pool and the total number of patients was 683 (322 in LSO and 361 in the MPT group). In terms of the early and late time of surgery, the LSO seems to be superior over the MPT approach but with heterogeneity (OR -0.21, CI 95% -0.59 to 0.18, and p=0.04) or (OR -0.21, CI 95% -0.69 to 0.28, and p=0.05), and (p=0.02 and I2=68.97%) or (p=0.05 and I2=61.74%) respectively. Regarding the subgroup of patients with the supra-early time of surgery, surgical duration, completed occlusion, technical intraoperative complications, postoperative infection, intraoperative rupture, vasospasm, good and poor neurological outcomes and clinical deterioration, there was no superiority of the one method over the other. Mini or keyhole craniotomy even challenging might be a good option for neurosurgeons. Particularly in ruptured noncomplex aneurysms' surgery LSO seems to be superior over the MPT approach in terms of the early time and in the late time of surgery but with heterogeneity.

Lateral supraorbital approach for resection of large and giant olfactory groove meningiomas: a single center experience.

BACKGROUND: The lateral supraorbital approach (LSO) provides an optimal access corridor for various skull bases lesions, including olfactory groove meningiomas (OGMs). The aim of this study is to describe the authors' experience with the management of large and giant OGMs utilizing the LSO approach and describe the technical nuances of the procedure. METHODS: A retrospective review of seven patients with large and giant OGMs managed with the LSO approach between 2013 and 2019 was performed. Radiographic and clinical data were recorded and analyzed. RESULTS: Seven patients with large and giant OGMs underwent surgical resection via the LSO approach. Six patients were female, with a median age of 56 years. Patients commonly presented with altered mentation, anosmia, and headaches. The average tumor volume was 120.6 ± 64.7 cm3 with five cases of vascular encasement. Simpson grade II resection was achieved in four patients while Simpson grade IV resection was achieved in three patients. The median length of stay was 2.0 days. The median preoperative Karnofsky Performance Scale (KPS) score was 70, improving to 100 at last postoperative follow-up visit. Two complications were encountered in the form of postoperative cerebrospinal fluid leak in one patient and a transient diplopia in another patient. Tumor recurrence/progression was identified in two patients during a median follow-up time of 65.5 months. Both cases have been managed with adjuvant radiosurgery. CONCLUSION: The LSO approach is a safe and effective minimally invasive transcranial corridor for the management of OGMs that should be part of the armamentarium of skull base neurosurgeons.

The Lateral Supraorbital Craniotomy Approach for Anterior Circulation Aneurysms: A Modern Surgical Case Series in the Endovascular Era.

BACKGROUND: The lateral supraorbital (LSO) approach is a minimally invasive modification of the standard pterional approach to anterior circulation aneurysms. This study aimed to describe a dual-trained cerebrovascular neurosurgeon's first 18-month experience with the LSO approach, including decision-making criteria and lessons learned. METHODS: This retrospective case series analyzed 50 consecutive patients treated with LSO craniotomy for aneurysm clipping by a single surgeon. Aneurysms were separated into 3 categories by location: internal carotid artery, anterior communicating artery, and middle cerebral artery. Surgical characteristics were evaluated for differences by location and rupture status. RESULTS: Aneurysm clipping via LSO was performed on 57 aneurysms in 50 patients. Fixed retraction was employed less often in patients with internal carotid artery aneurysms than in patients with anterior communicating artery, middle cerebral artery, or multiple aneurysms (10% vs. 68.2%, 45.5%, and 42.9, P = 0.02). Of patients, 26 (52%) presented with subarachnoid hemorrhage; the majority of patients (92.3%) had Hunt and Hess grade I-III. No differences were noted in intraoperative rupture rates, fixed retractor use, operative duration, or estimated blood loss by rupture status. Adverse events included permanent frontalis nerve palsy in 1 patient (2%), temporalis atrophy in 1 patient, and transient aphasia in 1 patient. No postoperative hematomas or strokes were observed. CONCLUSIONS: The LSO approach can safely and effectively treat anterior circulation aneurysms and should be considered a viable minimally invasive option for aneurysm clipping. Further studies comparing the LSO approach with other cranial approaches are needed.

Microsurgical Management of Posterior Circulation Aneurysms: A Retrospective Study on Epidemiology, Outcomes, and Surgical Approaches.

Posterior circulation aneurysms have been regarded as the most challenging for endovascular coiling and microsurgical occlusion. The role of microsurgical treatment is gradually being overlooked and diminishing in the trend of endovascular treatment. As microsurgical occlusion of posterior circulation aneurysms is decreasing, we present our relevant experience to evaluate treatment options and surgical approaches. A retrospective study was conducted in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University between 2016 and 2021. Patients with posterior circulation aneurysms treated by clipping, bypass, and trapping were enrolled and followed up for at least six months. We included 50 patients carrying 53 posterior circulation aneurysms, 43 of whom had aneurysm ruptures. The posterior cerebral artery and posterior inferior cerebellar artery were the most common aneurysm locations. Direct clipping was performed in 43 patients, while bypass and trapping was performed in six patients. The retrosigmoid, far-lateral, and midline or paramedian suboccipital approaches were performed for those aneurysms in the middle and lower thirds. Aneurysms in the upper third required the lateral supraorbital approach, pterional approach, subtemporal approach, and occipital craniotomy. The lateral supraorbital approach was utilized in seven patients for aneurysms above the posterior clinoid process. Thirty-four patients recovered well with modified Rankin score 0-3 at discharge. No patient experienced aneurysm recurrence during the mean follow-up period of 3.57 years. Microsurgery clipping and bypass should be considered in conjunction with endovascular treatment as a treatment option in posterior circulation aneurysms. The lateral supraorbital approach is a feasible, safe, and simple surgical approach for aneurysms above the posterior clinoid process.

Olfactory nerve sparing technique for anterior skull base meningiomas: how I do it.

BACKGROUND: Olfactory function preservation is a desirable objective in anterior skull base (ASB) surgery. The "infracerebral-supraolfactory nerve" corridor is presented. METHOD: The technique for preserving the olfactory nerves (OlfNs) in anterior ASB meningioma removal involves the following points: deep knowledge of the ASB vascular and meningeal anatomy, precise preoperative planning, wide and sharp dissection of the OlfNs away from the frontal lobes, gravity-aided frontal lobe retraction, Gelfoam-assisted hemostasis on nervous structures, and access to the lesion through an infracerebral-supraolfactory nerve corridor. CONCLUSIONS: This technique may be a valid option for patients affected by anterior skull base meningiomas with intact preoperative olfactory function.

Clip Ligation of Midsegment M1 Artery Aneurysm through a Lateral Supraorbital Approach: 2-Dimensional Operative Video.

Lenticulostriate middle cerebral artery (MCA) aneurysms are rare and often involve perforating vessels, making endovascular treatment difficult. When projecting superiorly, aneurysm rupture can likely cause intraparenchymal hemorrhage in basal ganglia. Consequently, surgical clip ligation requires control not to aggressively elevate the frontal lobe to avoid intraoperative injury. We report a case of a growing right midsegment MCA aneurysm treated with clip ligation via a lateral supraorbital approach (LSO). The patient is a 71-year-old female found to have a 4 mm × 3 mm right M1 aneurysm in 2014 on workup for headaches. Subsequent imaging demonstrated aneurysm growth to 6 mm × 3.1 mm with peaked-dome appearance. The growth and location of the aneurysm led us to recommend open surgical treatment; the patient provided informed written consent to proceed. We performed a standard right-sided LSO approach.1 Microdissection was performed to split the sylvian fissure distally and then proximally to expose the MCA on either side of the aneurysm. Dissecting the aneurysm revealed a perforating artery at the proximal neck. Using minimal frontal lobe dynamic retraction, microsurgical clip ligation was performed. We ensured the clip was placed in line with the MCA trunk to avoid kinking the parent artery and subsequent stroke. Intraoperative micro-Doppler and indocyanine green injection confirmed the patency of vasculature. Postoperative angiogram confirmed complete aneurysm ligation. The patient clinically did well and was discharged home on postoperative day 2. Our video demonstrates safe and effective surgical treatment of a rare aneurysm2 through a small LSO craniotomy approach (Video 1).

[Cavernous malformation of the optic nerve: clinical case and literature review]. / Kavernoznaia mal'formatsiia zritel'nogo nerva: sluchai iz praktiki i obzor literatury.

INTRODUCTION: Cavernous malformation (cm) of the optic nerve is a rare condition It is clinically presented by the so-called chiasmal apoplexy. Microsurgical removal of cavernous malformation is the method of choice. MATERIAL AND METHODS: Authors present a clinical case of the removal of cavernous malformation of the left optic nerve. RESULTS: The presented case demonstrates the successful removal of the CM of the left optic nerve from the lateral supraorbital access. In the postoperative period, visual disorders did not worsen. Control MRI of the brain showed total removal of cavernoma. CONCLUSION: Presented clinical case demonstrates the radical removal of CM of the optic nerve. Early and correct diagnosis makes it possible to adequately treat the patient and preserve his/her visual functions.

How I do it: contralateral supraorbital approach for tuberculum sellae meningioma.

BACKGROUND: The resection of tuberculum sellae meningiomas poses a challenge particularly when dealing with the medial aspect of the optic nerve. Dissection of the tumor off the optic nerve is usually carried out in the blind spot "behind" the optic nerve. We describe a contralateral approach for asymmetric tuberculum sellae meningiomas, allowing direct visualization of the medial optic nerve. METHOD: Contralateral lateral supraorbital approach was performed, and complete tumor resection was achieved without any injury to the optic nerve. CONCLUSION: The contralateral approach for asymmetric tuberculum sellae meningioma is an efficient technique allowing improved visualization of the medial optic nerve.

Lateral supraorbital versus pterional approach for parachiasmal meningiomas: surgical indications and esthetic benefits.

The lateral supraorbital (LSO) approach is a minimally invasive modification of the pterional approach. The authors assess the surgical indications and esthetic benefits of the LSO approach in comparison with the pterional approach for parachiasmal meningiomas. From April 2013 to May 2017, a total of 64 patients underwent surgery for parachiasmal meningiomas. Among them, tumor resection was performed with the LSO approach for 34 patients and pterional approach for 30 patients. A retrospective analysis was done on tumor characteristics, surgical outcome, approach-related morbidity, and esthetic outcome between the two approaches. Gross total resection was achieved in 33 of 34 patients (97.1%) with the LSO approach. There were no differences in tumor size, origin, consistency, internal carotid artery encasement, cranial nerve adhesion, and optic canal invasion between the two approaches. The most common tumor origin was the tuberculum sellae for both the LSO and pterional approaches. For tumors with preoperative visual compromise, immediate visual outcome improved or remained stable in 76% and 80.9% with the LSO and pterional approaches, respectively. Surgery time, surgical bleeding, hospital length of stay, and esthetic outcome were significantly shorter and superior with the LSO approach. There were no differences in surgical morbidity and brain retraction injury between the two approaches. The LSO approach can provide a safe, rapid, and minimally invasive exposure for parachiasmal meningiomas compared with the pterional approach. Surgeons must consider tumor size, origin, and extent in determining the resectability of the tumor rather than the extent of exposure.

Selection Strategy for Optimal Keyhole Approaches for Middle Cerebral Artery Aneurysms: Lateral Supraorbital Versus Minipterional Craniotomy.

BACKGROUND/OBJECTIVE: The lateral supraorbital (LS) and minipterional (MP) approaches have been reported for treating intracranial aneurysms as alternative to the pterional approach. We describe our decision making for selecting the minicraniotomy, LS versus MP, for managing noncomplex aneurysms of the middle cerebral artery (MCA), based on the depth of the aneurysm within the Sylvian fissure. METHODS: We report on a consecutive case series of 50 patients who underwent clipping of 54 ruptured/unruptured MCA aneurysms by means of LS or MP craniotomies. The distance between the MCA (M1) origin and the aneurysmal neck is key to selection of the approach: LS was used for MCA aneurysms <15 mm from the M1 origin and MP for MCA aneurysms ≥15 mm from the M1 origin. RESULTS: 11 of 50 patients presented with subarachnoid hemorrhage (10 ruptured MCA aneurysms). Overall, 59 aneurysms were successfully clipped (54 of the MCA). The mean distance between the M1 origin and the aneurysmal neck was 10.1 mm (range, 4-17 mm) for patients treated by LS and 20 mm (range, 15-30 mm) for those treated by MP. All but 1 MCA aneurysms were successfully treated. At last follow-up (mean, 14 months), no reperfusion of the clipped aneurysms was observed. CONCLUSION: Our strategy for selecting the keyhole approach based on the depth of the aneurysm within the Sylvian fissure is efficient and safe. We suggest the use of the LS approach when the aneurysm is <15 mm from the M1 origin and the MP approach when the aneurysm is ≥15 mm from the M1 origin.

Anterior clinoidectomy for paraclinoid aneurysms in Helsinki Neurosurgery.

BACKGROUND: In this video abstract, we present an intradural anterior clinoidectomy for management of some paraclinoid aneurysms. Quick adenosine cardiac arrest performed instead of an anterior clinoidectomy and proximal temporary clipping usually allows us a proximal control of aneurysms in Helsinki Neurosurgery. However, when the neck of the aneurysm remains hidden under the anterior clinoid process, or when some complex aneurysms have reduced space for placing temporary clips obstructing the definitive clipping, anterior clinoidectomy is the most available option. TECHNIQUE: The patient with multiple intracranial aneurysms had a ruptured anterior cerebral artery aneurysm associated with a right middle cerebral artery aneurysm and a right small paraclinoid aneurysm. The patient underwent surgical clipping of all aneurysms by a right lateral supraorbital approach at one-stage surgery. After the associated aneurysms were clipped, the hidden paraclinoid aneurysm required an anterior clinoidectomy for definitive clipping. A small durotomy over the anterior clinoid process was made with microscissors after bipolar coagulation. Subsequently, the anterior clinoidectomy was performed under visual control with the use of an electric high-speed diamond drill (3 mm diameter). The direction and size of the drilling were performed according to the anatomical configuration and exact location of the aneurysm determined by the preoperative radiological analysis of the case. A definitive clip was applied after complete visualization of aneurysm. Postoperative computed tomography angiography demonstrated absence of complications. CONCLUSION: Anterior clinoidectomy is a useful procedure aiming at a proper definitive clipping of paraclinoid aneurysms with challenging locations and configurations. VIDEOLINK: http://surgicalneurologyint.com/videogallery/right-clinoidectomy/.

One burr-hole craniotomy: Lateral supraorbital approach in Helsinki Neurosurgery.

BACKGROUND: In this video abstract, we present a one burr-hole craniotomy for the standard lateral supraorbital approach (LSO) developed by Helsinki Neurosurgery. This is a more aesthetic variant of the classic pterional approach. Presently, the LSO approach is most commonly used at our institution. With the LSO technique, the temporal muscle is just minimally opened close to its superior insertion. Posterior and temporal extension of the craniotomy, furthermore, allows adequate access to the anterior skull base, the sellar and suprasellar regions, the middle cranial fossa, the anterior portion of the Sylvian fissure, and the distal Sylvian fissure. Even though the specific location and size of the lesion may vary, this approach accesses all mentioned structures with a very minimal variation. CASE DESCRIPTION: The patient with an unruptured anterior communicating artery aneurysm is placed in supine position with the head elevated 30 cm from the level of the heart. The head position is determined by the specific location of the lesion. A curved frontotemporal skin incision is made behind the hairline which stops 2-3 cm above the zygoma. Anterior retraction and hemostatic Raney clips placed at the posterior border of the skin flap maintain a clean space for the craniotomy. A burr-hole is made at the level of the temporal line in the frontal bone. After the dura is detached with blunt dissection, a craniotomy is performed to reach the anterior skull base. A few drill holes are made for tack-up sutures and the dura is opened using conventional techniques. The anterior skull base, sellar/suprasellar regions, and select lesions located in the upper basilar region may be accessed through this subfrontal approach. Middle cerebral artery aneurysms and lesions located along the sylvian fissure or in the middle fossas may also be approached with this exposure, but would require further opening of the proximal sylvian fissure. CONCLUSION: There we described the LSO one burr-hole craniotomy technique that may represent a more efficient procedure for performing LSO. VIDEOLINK: "http://surgicalneurologyint.com/videogallery/lso-right-side/"\t"_blank" http://surgicalneurologyint.com/videogallery/lso-right-side/.