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Background and Objectives: Microsurgical resection is the only curative intervention for symptomatic brainstem cavernous malformations (BSCMs), but the management of these lesions in older adults (≥65 years) is not well described. This study sought to address this gap by examining the safety and efficacy of BSCM resection in a cohort of older adults., Methods: Records of patients who underwent BSCM resection over a 30-year period were reviewed retrospectively. Baseline characteristics and outcomes were compared between older (≥65 years) and younger (<65 years) patients., Results: Of 550 patients with BSCM who met inclusion criteria, 41 (7.5%) were older than 65 years. Midbrain (43.9% vs 26.1%) and medullary lesions (19.5% vs 13.6%) were more common in the older cohort than in the younger cohort ( P = .01). Components of the Lawton BSCM grading system (ie, lesion size, crossing axial midpoint, developmental venous anomaly, and timing of hemorrhage) were not significantly different between cohorts ( P ≥ .11). Mean (SD) Elixhauser comorbidity score was significantly higher in older patients (1.86 [1.06]) than in younger patients (0.66 [0.95]; P < .001). Older patients were significantly more likely than younger patients to have poor outcomes at final follow-up (28.9% vs 13.8%, P = .01; mean follow-up duration, 28.7 [39.1] months). However, regarding relative neurological outcome (preoperative modified Rankin Scale to final modified Rankin Scale), rate of worsening was not significantly different between older and younger patients (23.7% vs 14.9%, P = .15)., Conclusion: BSCMs can be safely resected in older patients, and when each patient's unique health status and life expectancy are taken into account, these patients can have outcomes similar to younger patients., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background: Spetzler-Martin (SM) grade III arteriovenous malformations (AVMs) are at the boundary of safe operability, and preoperative embolization may reduce surgical risks., Objective: To evaluate the benefits of preoperative AVM embolization by comparing neurological outcomes in patients with grade III AVMs treated with or without preoperative embolization., Methods: All microsurgically treated grade III AVMs were identified from 2011 to 2018 at 2 medical centers. Neurological outcomes, measured as final modified Rankin Scale scores (mRS) and changes in mRS from preoperative baseline to last follow-up evaluation, were compared in patients with and without preoperative embolization., Results: Of the 102 patients with grade III AVMs who were treated microsurgically, 57 (56%) underwent preoperative embolization. Significant differences were found between the patients with and without embolization in AVM eloquence (74% vs 93%, P = .02), size ≥ 3 cm (47% vs 73%, P = .01), diffuseness (7% vs 22%, P = .04), and mean final mRS (1.1 vs 2.0, P = .005). Poor outcomes were more frequent in patients without embolization (38%) than with embolization (7%) (final mRS > 2; P < .001). Propensity-adjusted analysis revealed AVM resection without embolization was a risk factor for poor outcome (mRS score > 2; odds ratio, 4.2; 95% CI, 1.1-16; P = .03)., Conclusion: Nonembolization of SM grade III AVMs is associated with an increased risk of poor neurological outcomes after microsurgical resection. Preoperative embolization of intermediate-grade AVMs selected because of large AVM size, surgical inaccessibility of feeding arteries, and high flow should be employed more often than anticipated, even in the context of increasing microsurgical experience with AVMs., (© Congress of Neurological Surgeons 2021.)

Objective: A direct comparison of endovascular versus microsurgical treatment of ruptured middle cerebral artery (MCA) aneurysms in randomized trials is lacking. As endovascular treatment strategies continue to evolve, the number of reports of endovascular treatment of these lesions is increasing. Herein, the authors report a detailed post hoc analysis of ruptured MCA aneurysms treated by microsurgical clipping from the Barrow Ruptured Aneurysm Trial (BRAT)., Methods: The cases of patients enrolled in the BRAT who underwent microsurgical clipping for a ruptured MCA aneurysm were reviewed. Characteristics of patients and their clinical outcomes and long-term angiographic results were analyzed., Results: Fifty patients underwent microsurgical clipping of a ruptured MCA aneurysm in the BRAT, including 21 who crossed over from the endovascular treatment arm. Four patients with nonsaccular (e.g., dissecting, fusiform, or blister) aneurysms were excluded, leaving 46 patients for analysis. Most (n = 32; 70%) patients presented with a Hunt and Hess grade II or III subarachnoid hemorrhage, with a high prevalence of intraparenchymal blood (n = 23; 50%), intraventricular blood (n = 21; 46%), or both. At the last follow-up (up to 6 years after treatment), clinical outcomes were good (modified Rankin Scale score 0–2) in 70% (n = 19) of 27 Hunt and Hess grades I–III patients and in 36% (n = 4) of 11 Hunt and Hess grade IV or V patients. There were no instances of rebleeding after the surgical clipping of aneurysms in this series at the time of last clinical follow-up., Conclusions: Microsurgical clipping of ruptured MCA aneurysms has several advantages over endovascular treatment, including durability over time. The authors report detailed outcome data of patients with ruptured MCA aneurysms who underwent microsurgical clipping as part of a prospective, randomized trial. These results should be used for comparison with future endovascular and surgical series to ensure that the best results are being achieved for patients with ruptured MCA aneurysms.

Background: Cerebellar arteriovenous malformations (CAVMs) are challenging to treat given their close proximity to the brain stem, greater propensity for rupture, and greater rates of morbidity and mortality than other brain arteriovenous malformations. The present investigation sought to describe and characterize the features of these rare and unique lesions., Methods: A retrospective review of CAVM cases treated at 2 tertiary medical centers was performed. Patients surgically treated at institution 1 from September 1999 to February 2013 and institution 2 from October 2008 to October 2015 were included., Results: A total of 120 patients had been treated. Of the 120 patients, 85 (70.8%) had initially presented with hemorrhage, 45 (37.5%) of whom experienced hemorrhage requiring emergent surgery. A favorable neurological outcome was observed in 76 patients (63.3%; modified Rankin Scale score <3). The perioperative mortality was 2.5% (n = 3). The long-term mortality rate was 7.5% (n = 9). The mean follow-up time was 1.82 years. On average, the patients with large CAVMs (≥3 cm; P ≤ 0.001), who had received embolization before surgery (P = 0.04), did not have an associated aneurysm (P ≤ 0.001), or had a residual CAVM after surgery (P = 0.008) were significantly younger. Female patients had fewer CAVMs with deep venous drainage (54.3% vs. 72.3%; P = 0.049), experienced decreased mortality (1.4% vs. 16.7%; P = 0.003), and were less likely to have worse neurological status after treatment (P = 0.003)., Conclusions: CAVMs are rare lesions that exhibit unique disease characteristics. Although most patients will experience a favorable outcome, CAVMs frequently present with hemorrhage, result in high rates of morbidity and mortality, and characteristically differ depending on patient age and gender., (Copyright © 2018. Published by Elsevier Inc.)

Background: Despite the latest developments in microsurgery, electrophysiological monitoring, and neuroimaging, the surgical management of intrinsic brainstem lesions remains challenging. Several safe entry points have been described to access the different surfaces of the brainstem. Knowledge of this entry zone anatomy is critical to performing a safe and less morbid approach. To access the anterior midbrain surface, a well-known entry point is the anterior mesencephalic (AM) zone. Our aim was to quantify surgical AM zone exposure through the orbitozygomatic (OZ) and subtemporal (ST) approaches. We also analyzed the angular exposure along the horizontal and vertical axis angles for the AM zone., Methods: Ten cadaveric heads were dissected using the OZ and ST approaches for anterior midbrain surface exposure. A neuronavigation system was used to determine the 3-dimensional coordinates. The area of surgical exposure, angular exposure, and anatomical limits of each craniotomy were evaluated and determined using software analysis and compared for intersection areas and AM safe zone exposure., Results: The median surgical exposure was 164.7 ± 43.6 mm 2 for OZ and 369.8 ± 70.1 mm 2 for ST (P = 0.001). The vertical angular exposure was 37.7° ± 9.92° for the OZ and 18.4° ± 2.8° for the ST opening (P < 0.001). The horizontal angular exposure to the AM zone was 37.9° ± 7.3° for the OZ and 47.0° ± 3.2° for the ST opening (P = 0.002)., Conclusions: Although the OZ craniotomy offers reduced surgical exposure, it provides a better trajectory to the AM zone compared with the ST approach., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVE Overlapping surgery is a controversial subject in medicine today; however, few studies have examined the outcomes of this practice. The authors analyzed outcomes of patients with acutely ruptured saccular aneurysms who were treated with microsurgical clipping in a prospectively collected database from the Barrow Ruptured Aneurysm Trial. Acute and long-term outcomes for overlapping versus nonoverlapping cases were compared. METHODS During the study period, 241 patients with ruptured saccular aneurysms underwent microsurgical clipping. Patients were separated into overlapping (n = 123) and nonoverlapping (n = 118) groups based on surgical start/stop times. Outcomes at discharge and at 6 months, 1 year, 3 years, and 6 years after surgery were analyzed. RESULTS Patient variables (e.g., age, smoking status, cardiovascular history, Hunt and Hess grade, Fisher grade, and aneurysm size) were similar between the 2 groups. Aneurysm locations were similar, with the exception of the overlapping group having more posterior circulation aneurysms (18/123 [15%]) than the nonoverlapping group (8/118 [7%]) (p = 0.0495). Confirmed aneurysm obliteration at discharge was significantly higher for the overlapping group (109/119 [91.6%]) than for the nonoverlapping group (95/116 [81.9%]) (p = 0.03). Hospital length of stay, discharge location, and proportions of patients with a modified Rankin Scale (mRS) score > 2 at discharge and up to 6 years postoperatively were similar. The mean and median mRS, Glasgow Outcome Scale, Mini-Mental State Examination, National Institutes of Health Stroke Scale, and Barthel Index scores at all time points were not statistically different between the groups. CONCLUSIONS Compared with nonoverlapping surgery, overlapping surgery was not associated with worse outcomes for any variable at any time point, despite the complexity of the surgical management in this patient population. These findings should be considered during the discussion of future guidelines on the practice of overlapping surgery.

Objectives: Frozen section histological analysis is currently the mainstay for intraprocedural tissue diagnosis during the resection of intracranial neoplasms and for evaluating tumor margins. However, frozen sections are time-consuming and often do not reveal the histological features needed for final diagnosis when compared with permanent sections. Confocal scanning microscopy (CSM) with certain stains may be a valuable technology that can add rapid and detailed histological assessment advantage for the neurosurgical operating room. This study describes potential advantages of CSM imaging of fresh human brain tumor tissues labeled with acriflavine (AF), acridine orange (AO), cresyl violet (CV), methylene blue (MB), and indocyanine green (ICG) within the neurosurgical operating room facility., Patients and Methods: Acute slices from orthotopic human intracranial neoplasms were incubated with AF/AO and CV solutions for 10 s and 1 min respectively. Staining was also attempted with MB and ICG. Samples were imaged using a bench-top CSM system. Histopathologic features of corresponding CSM and permanent hematoxylin and eosin images were reviewed for each case., Results: Of 106 cases, 30 were meningiomas, 19 gliomas, 13 pituitary adenomas, 9 metastases, 6 schwannomas, 4 ependymomas, and 25 other pathologies. CSM using rapid fluorophores (AF, AO, CV) revealed striking microvascular, cellular and subcellular structures that correlated with conventional histology. By rapidly staining and optically sectioning freshly resected tissue, images were generated for intraoperative consultations in less than one minute. With this technique, an entire resected tissue sample was imaged and digitally stored for tele-pathology and archiving., Conclusion: CSM of fresh human brain tumor tissue provides clinically meaningful and rapid histopathological assessment much faster than frozen section. With appropriate stains, including specific cellular structure or antibody staining, CSM could improve the timeliness of intraoperative decision-making, and the neurosurgical-pathology workflow during resection of human brain tumors, ultimately improving patient care., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Microneurosurgical techniques involve complex manual skills and hand-eye coordination that require substantial training. Many factors affect microneurosurgical skills. The goal of this study was to use a systematic evidence-based approach to analyze the quality of evidence for intrinsic and extrinsic factors that influence microneurosurgical performance and to make weighted practical recommendations., Methods: A literature search of factors that may affect microsurgical performance was conducted using PubMed and Embase. The criteria for inclusion were established in accordance with the PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) statement., Results: Forty-eight studies were included in the analysis. Most of the studies used surgeons as participants. Most used endoscopic surgery simulators to assess skills, and only 12 studies focused on microsurgery. This review provides 18 practical recommendations based on a systematic literature analysis of the following 8 domains: 1) listening to music before and during microsurgery, 2) caffeine consumption, 3) β-blocker use, 4) physical exercise, 5) sleep deprivation, 6) alcohol consumption before performing surgery, 7) duration of the operation, and 8) the ergonomic position of the surgeon., Conclusions: Despite the clear value of determining the effects of various factors on surgical performance, the available body of literature is limited, and it is not possible to determine standards for each surgical field. These recommendations may be used by neurosurgical trainees and practicing neurosurgeons to improve microsurgical performance and acquisition of microsurgical skills. Randomized studies assessing the factors that influence microsurgical performance are required., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The authors describe the interpeduncular fossa safe entry zone as a route for resection of ventromedial midbrain lesions. To illustrate the utility of this novel safe entry zone, the authors provide clinical data from 2 patients who underwent contralateral orbitozygomatic transinterpeduncular fossa approaches to deep cavernous malformations located medial to the oculomotor nerve (cranial nerve [CN] III). These cases are supplemented by anatomical information from 6 formalin-fixed adult human brainstems and 4 silicone-injected adult human cadaveric heads on which the fiber dissection technique was used. The interpeduncular fossa may be incised to resect anteriorly located lesions that are medial to the oculomotor nerve and can serve as an alternative to the anterior mesencephalic safe entry zone (i.e., perioculomotor safe entry zone) for resection of ventromedial midbrain lesions. The interpeduncular fossa safe entry zone is best approached using a modified orbitozygomatic craniotomy and uses the space between the mammillary bodies and the top of the basilar artery to gain access to ventromedial lesions located in the ventral mesencephalon and medial to the oculomotor nerve.

Objective: In our study, we comprehensively detail the technique of the low retrosigmoid approach to the lateral medullary area, including the inferior cerebellar peduncle, postolivary sulcus, pontomedullary sulcus, and inferior olivary nucleus, as well as the lateral recess of the fourth ventricle., Methods: Four formalin-fixed, silicone-injected, cadaveric human heads were examined under the operating microscope to demonstrate pertinent descriptive anatomy using the low retrosigmoid approach in a stepwise manner. Clinical parameters of a patient with a lateral medullary lesion were reviewed retrospectively to describe preoperative and postoperative examination and surgical details of the approach to the lateral medulla., Results: The clinical case report describes a low retrosigmoid craniotomy performed to access the exiting points of cranial nerves IX (glossopharyngeal) and X (vagus), foramen of Luschka, inferior cerebellar peduncle (lateral medullary zone), postolivary sulcus, and olivary nucleus. The lesion was exposed using the inferior cerebellar peduncle and removed using standard microsurgical technique., Conclusions: The lower retrosigmoid infratonsillar approach provides excellent exposure to medullary safe entry zones, including the transolivary, postolivary sulcus, pontomedullary sulcus, and lateral medullary (inferior cerebellar peduncle) zones, for removal of lesions in this area., (Copyright © 2017 Elsevier Inc. All rights reserved.)

OBJECTIVE Fusiform cerebral aneurysms represent a small portion of intracranial aneurysms; differ in natural history, anatomy, and pathology; and can be difficult to treat compared with saccular aneurysms. The purpose of this study was to examine the techniques of treatment of ruptured and unruptured fusiform intracranial aneurysms and patient outcomes. METHODS In 45 patients with fusiform aneurysms, the authors retrospectively reviewed the presentation, location, and shape of the aneurysm; the microsurgical technique; the outcome at discharge and last follow-up; and the change in the aneurysm at last angiographic follow-up. RESULTS Overall, 48 fusiform aneurysms were treated in 45 patients (18 male, 27 female) with a mean age of 49 years (median 51 years; range 6 months-76 years). Twelve patients (27%) had ruptured aneurysms and 33 (73%) had unruptured aneurysms. The mean aneurysm size was 8.9 mm (range 6-28 mm). The aneurysms were treated by clip reconstruction (n = 22 [46%]), clip-wrapping (n = 18 [38%]), and vascular bypass (n = 8 [17%]). The mean (SD) hospital stay was 19.0 ± 7.4 days for the 12 patients with subarachnoid hemorrhage and 7.0 ± 5.6 days for the 33 patients with unruptured aneurysms. The mean follow-up was 38.7 ± 29.5 months (median 36 months; range 6-96 months). The mean Glasgow Outcome Scale score for the 12 patients with subarachnoid hemorrhage was 3.9; for the 33 patients with unruptured aneurysms, it was 4.8. No rehemorrhages occurred during follow-up. The overall annual risk of recurrence was 2% and that of rehemorrhage was 0%. CONCLUSIONS Fusiform and dolichoectatic aneurysms involving the entire vessel wall must be investigated individually. Although some of these aneurysms may be amenable to primary clipping and clip reconstruction, these complex lesions often require alternative microsurgical and endovascular treatment. These techniques can be performed with acceptable morbidity and mortality rates and with low rates of early rebleeding and recurrence.

CLOVES (congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and scoliosis/skeletal/spinal anomalies) syndrome is a congenital and almost exclusively pediatric syndrome associated with vascular malformations of the neuroaxis. We report the case of a complex spinal arteriovenous fistula in an adult woman with CLOVES syndrome treated using a multidisciplinary approach with endovascular embolization and microsurgical technique, and review the medical literature on this disease., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Ruptured blister aneurysms of the carotid artery are difficult to safely treat. We present a novel strategy of microsurgical clip wrapping of internal carotid artery blister aneurysms in the setting of acute rupture, followed by delayed placement of a pipeline embolization device for definitive treatment., Clinical Presentation: We present two cases of ruptured blister aneurysms of the internal carotid artery treated by wrapping of the diseased segment of the vessel, followed by delayed deployment of a flow diverting stent once the patient was out of the vasospasm window but during the same hospitalization., Results: Clip wrapping followed by flow diversion in a delayed fashion results in anatomic remodeling of the diseased artery without a high morbidity., Conclusions: A combined approach of acute surgical stabilization followed by definitive endovascular reconstruction may reduce hemorrhagic complications while improving long term treatment durability., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

OBJECT The aim of this study was to enhance the planning and use of microsurgical resection techniques for intrinsic brainstem lesions by better defining anatomical safe entry zones. METHODS Five cadaveric heads were dissected using 10 surgical approaches per head. Stepwise dissections focused on the actual areas of brainstem surface that were exposed through each approach and an analysis of the structures found, as well as which safe entry zones were accessible via each of the 10 surgical windows. RESULTS Thirteen safe entry zones have been reported and validated for approaching lesions in the brainstem, including the anterior mesencephalic zone, lateral mesencephalic sulcus, intercollicular region, peritrigeminal zone, supratrigeminal zone, lateral pontine zone, supracollicularzone, infracollicularzone, median sulcus of the fourth ventricle, anterolateral and posterior median sulci of the medulla, olivary zone, and lateral medullary zone. A discussion of the approaches, anatomy, and limitations of these entry zones is included. CONCLUSIONS A detailed understanding of the anatomy, area of exposure, and safe entry zones for each major approach allows for improved surgical planning and dissemination of the techniques required to successfully resect intrinsic brainstem lesions.

Objective: We used microscopy to conduct qualitative and quantitative analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric, subtemporal (ST), and transchoroidal (TC). In addition, we performed a parahippocampal gyrus resection in the ST context., Methods: Each approach was performed in 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the parahippocampal gyrus was resected through an ST approach. The qualitative analysis was based on anatomic observation and the quantitative analysis was based on the linear exposure of vascular structures and the area of exposure of the ambient cistern region., Results: The ST approach provided good exposure of the inferior portion of the cistern and of the proximal segments of the posterior cerebral artery. After the resection of the parahippocampal gyrus, the area of exposure improved in all components, especially the superior area. A TC approach provided the best exposure of the superior area compared with the other approaches. The posterolateral approaches (SC/occipital interhemispheric) to the ambient cistern region provided similar exposure of anatomic structures. There was a significant difference (P < 0.05) in linear exposure of the posterior cerebral artery when comparing the ST/TC and ST/SC approaches., Conclusions: This study has demonstrated that surgical approaches expose dissimilarly the different regions of the ambient cistern and an approach should be selected based on the specific need of anatomic exposure., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Blister-like aneurysms (BLAs) are challenging lesions that require unique microsurgical strategies. BLAs are predominantly found along the internal carotid artery; however, BLAs of the basilar artery are a rare subset that requires a modified treatment strategy., Objective: To discuss the microsurgical management and review the long-term outcomes of patients with BLAs of the basilar artery., Methods: We retrospectively reviewed the surgical technique, postoperative results, and long-term outcomes of all patients with basilar artery BLAs treated at our institution from 2005 to 2011., Results: Four patients with basilar artery BLAs were identified over this 6-year interval. All 4 patients were treated by direct microsurgical clipping. A thin layer of cotton reinforcement was used beneath the clip tines to minimize the risk of clip slippage in 2 of 4 patients; 1 patient required adjunctive endovascular stent placement for residual aneurysm after clipping. Complete obliteration of all aneurysms was achieved, and there has been no recurrence at mean clinical follow-up of 72 months (median, 74.5; range, 37-103) and imaging follow-up of 48 months (median, 54; range 12-72)., Conclusion: Direct clipping with or without cotton reinforcement can obliterate basilar BLAs with excellent long-term outcomes. Clip wrapping is not an option for these lesions given the proximity to perforating branches. Endovascular techniques provide a useful adjunctive strategy; however, risks with antiplatelet therapy in the acute subarachnoid hemorrhage period must be considered.

A 70-year-old man with progressive visual disturbances, left superior quadrantanopsia, and right-sided papilledema underwent imaging that demonstrated a right internal carotid artery (ICA) terminus aneurysm with third-ventricle mass effect and ipsilateral optic nerve and chiasm compression. We performed a right modified orbitozygomatic craniotomy, with proximal control and dissection of the aneurysm and small perforator arteries. Temporary ICA and anterior cerebral artery (ACA) clips allowed placement of a large curved permanent clip, reconstructing the ICA bifurcation and maintaining adequate patency of the ACA and middle cerebral artery. Complete aneurysm obliteration was confirmed by intraoperative indocyanine green angiography and postoperative CT angiography. The video can be found here: http://youtu.be/5WEEgmA-g2A.

Unruptured posterior circulation aneurysms pose a treatment challenge. Although data supports the use of endovascular technique for select ruptured cases, in unruptured cases, there may be clinical equipoise. Furthermore, wide-necked basilar apex aneurysms commonly require the use of stents and placement of patients on dual therapy. We present a case of a healthy 50-year-old woman with an incidental basilar tip aneurysm treated via an orbitozygomatic craniotomy. This video highlights the steps of dynamic retraction, which is retraction without placement of permanent rigid retraction system, and the added maneuverability afforded by the use of the mouthpiece on the microscope. The video can be found here: http://youtu.be/jVfC6CCXdZY .

Intraoperative rupture of an intracranial aneurysm is a potentially devastating but controllable complication. The authors have successfully used the previously described cotton-clip technique to repair tears at the necks of aneurysms. (1-4) A tear on the neck of the aneurysm is covered with a piece of cotton and held in place with a suction device. The cotton is then clipped onto the tear with an aneurysm clip, using the cotton as a bolster. This simple, effective method has been useful in repairing a partial avulsion of the neck of an aneurysm. (1 , 3) The video can be found here: http://youtu.be/nT86RYVQWpc .

Background: The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients., Objective: To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone., Methods: Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers., Results: In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P < .001). Stratified analysis fitting models within 3 different follow-up groupings (<6 months, 6 months-2 years, and >2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SM-Supp grades ≤6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades >6 (39%-63%)., Conclusion: This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of 6 is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

Middle cerebral artery aneurysms, especially those with complex morphology, are considered excellent aneurysms for surgical clipping, given the challenges that exist with current endovascular techniques. We present a case of a large, complex, left middle cerebral artery aneurysm treated with microsurgical clipping. This video highlights critical steps in obtaining proximal and distal control as well as subarachnoid dissection necessary to prepare the aneurysm for final clipping. The video can be found here: http://youtu.be/RlKH2Km9z5Y .

Posterior circulation aneurysms are commonly treated with endovascular techniques. In select cases, microsurgery remains an essential tool for treating these lesions. We present a case of a ruptured posterior inferior cerebellar artery (PICA) aneurysm approached via a craniotomy. Given the labyrinth of neurovascular bundles present in the posterior fossa, surgical exposure of PICA aneurysms can be challenging. This video demonstrates the steps of the craniotomy, subarachnoid dissection, mobilization of the vertebral artery and lower cranial nerves, and clipping of the aneurysm. The video can be found here: http://youtu.be/fQSxQj7oL0U .

We present the case of a 26-year-old female patient who had two episodes of sudden, left, upper and lower extremity paresthesias and weakness, which resolved completely after 5 months. After recovery, she presented for evaluation. Imaging demonstrated a C3-C6 intra- and extra-axial arteriovenous malformation (AVM) with spinal cord compression and edema. A spinal angiogram showed arterial feeders arising from both vertebral arteries and from the right ascending pharyngeal artery. The AVM had been partially embolized after her first bleeding episode. She underwent C3-C6 laminoplasty and microsurgical resection of the AVM. After locating the main arterial feeders and draining veins, the malformation was resected using the pial resection technique. A postoperative spinal angiogram demonstrated gross total resection. Video used with permission from Barrow Neurological Institute. The video can be found here: http://youtu.be/JbbIwCTUsuI.

Object: Aneurysms are relatively rare in the pediatric population and tend to include a greater proportion of large and giant lesions. A subset of these large and giant aneurysms are not amenable to direct surgical clipping and require complex treatment strategies and revascularization techniques. There are limited data available on the management of these lesions in the pediatric population. This study was undertaken to evaluate the outcome of treatment of large and giant aneurysms that required microsurgical revascularization and vessel sacrifice in this population., Methods: The authors retrospectively identified all cases in which pediatric patients (age < 18 years) with aneurysms were treated using cerebral revascularization in combination with other treatment modalities at their institution between 1989 and 2013., Results: The authors identified 27 consecutive patients (19 male and 8 female) with 29 aneurysms. The mean age of the patients at the time of treatment was 11.5 years (median 13 years, range 1-17 years). Five patients presented with subarachnoid hemorrhage, 11 with symptoms related to mass effect, 2 with stroke, and 3 with seizures; in 6 cases, the aneurysms were incidental findings. Aneurysms were located along the internal carotid artery (n = 7), posterior cerebral artery (PCA) (n = 2), anterior cerebral artery (n = 2), middle cerebral artery (MCA) (n = 14), basilar artery (n = 2), vertebral artery (n = 1), and at the vertebrobasilar junction (n = 1). Thirteen were giant aneurysms (45%). The majority of the aneurysms were fusiform (n = 19, 66%), followed by saccular (n = 10, 34%). Three cases were previously treated using microsurgery (n = 2) or an endovascular procedure (n = 1). A total of 28 revascularization procedures were performed, including superficial temporal artery (STA) to MCA (n = 6), STA to PCA (n = 1), occipital artery to PCA (n = 1), extracranial-intracranial (EC-IC) bypass using radial artery graft (n = 3), EC-IC using a saphenous vein graft (n = 7), STA onlay (n = 3), end-to-end anastomosis (n = 1), and in situ bypasses (n = 6). Perioperative stroke occurred in 4 patients, but only one remained dependent (Glasgow Outcome Scale [GOS] score 3). At a mean clinical follow-up of 46 months (median 14 months, range 1-232 months), 26 patients had a good outcome (GOS score 4 or 5). There were no deaths. Five patients had documented occlusion of the bypass graft. The majority of aneurysms (n = 24) were obliterated at last follow-up. There was a single case of a residual aneurysm and one case of recurrence. Angiographic follow-up was unavailable in 3 cases., Conclusions: Cerebral revascularization remains an essential tool in the treatment of complex cerebral aneurysms in children.

Objective: The CO2 laser has a long record of use in neurosurgery. However, its utility has been limited by its bulky design and the challenge of using it with the operating microscope. With the development of the OmniGuide fiber, a technology that delivers the beam through flexible hollow-core photonic bandgap mirrors, the laser can now be held and used with greater ease and accuracy., Methods: We retrospectively analyzed a prospectively maintained database to assess the utility of the laser in 23 consecutive patients (10 male, 13 female; mean age, 40.8 years; range, 9-64 years) with a cavernous malformation treated by the senior author (R.F.S.)., Results: Four lesions were located in noneloquent areas, 13 were in the brain stem, four were in the spinal cord, and two were in the thalamus. The usefulness of the laser was rated on a scale of 1 to 5, with 5 defined as "extremely helpful." The mean utility score was 3.5 ± 0.94 (range, 2-5). The laser was judged most useful in creating cortisectomies in eloquent areas and in "shrinking" cavernous malformations away from adjacent hemosiderin-stained tissue. The laser was ineffective against calcification and in obtaining hemostasis., Conclusions: The CO2 laser is a useful addition to the neurosurgical armamentarium for treating lesions in the brainstem, thalamus, and spinal cord. Its primary utility lies in its ability to create focused cortisectomies safely and to shrink cavernous malformations away from eloquent hemosiderin-stained brain., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Aneurysms of the lenticulostriate artery have been associated with hypertension, vasculopathy, tumors, and arteriovenous malformations. Although several cases of microsurgical treatment of ruptured lenticulostriate artery aneurysms have been reported, to our knowledge there is no published case of microsurgical treatment of an unruptured lenticulostriate artery aneurysm. We report a 66-year-old woman with a history of moyamoya disease, previously treated with a right-sided middle cerebral artery-to-superficial temporal artery bypass who presented with an unruptured aneurysm of a lenticulostriate artery. We report successful microsurgical treatment of this rare lesion and discuss the rationale for our treatment strategy., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Background: Conus medullaris arteriovenous malformations (AVMs) are rare, challenging spinal vascular lesions that cause progressive debilitating myeloradiculopathy. Only sporadic reports of conus AVMs have been published., Objective: To better define the presentation, prognosis, and optimal treatment of these lesions, we present the first case series of conus AVMs, reflecting over 2 decades of experience with a multimodality endovascular and surgical approach., Methods: We retrospectively reviewed the charts of 16 patients with a conus AVM evaluated at our institution from 1989 to 2010. For each patient, the following clinical data were collected: age, sex, symptoms, angiographic findings, type of treatment, complications, degree of angiographic obliteration, recurrence at follow-up, and need for re-treatment. Ambulatory status, Frankel Grade, motor function, and bladder/bowel function were assessed before treatment, at discharge, and at last follow-up., Results: All 16 patients were treated. Eight (50%) patients underwent embolization followed by microsurgical resection, and 8 (50%) underwent microsurgical resection only. The rate of complete angiographic obliteration was 88%. At last follow-up (mean, 70 months), 43% of patients neurologically improved, 43% were stable, and 14% worsened in comparison with before treatment. During follow-up, 3 recurrences were detected, including the only 2 instances of long-term neurological decline. In the absence of recurrence, all patients ambulatory before treatment remained ambulatory at follow-up, whereas 75% of the initially nonambulatory patients regained the ability to walk., Conclusion: Although conus AVMs are challenging to treat, excellent long-term outcomes are possible with a multimodality approach. Recurrence is associated with long-term neurological decline and calls for close follow-up.

Object: Intramedullary, or glomus, spinal arteriovenous malformations (AVMs) are rare vascular lesions amenable to resection with or without adjuvant embolization. The authors retrospectively reviewed the senior author's (R.F.S.'s) surgical series of intramedullary spinal AVMs to evaluate clinical and radiographic outcomes., Methods: Detailed chart and radiographic reviews were performed for all patients with intramedullary spinal AVMs who underwent surgical treatment between 1994 and 2011. Presenting and follow-up neurological examination results were obtained and graded using the modified Rankin Scale (mRS) and McCormick Scale. Surgical technique, outcomes, complications, and long-term angiographic studies were reviewed., Results: During the study period, 20 patients (10 males and 10 females) underwent resection of glomus spinal AVMs. The mean age at presentation was 30 ± 17 years (range 7-62 years). The location of the AVMs was as follows: cervical spine (n = 10), thoracic spine (n = 9), and cervicothoracic junction (n = 1). The most common presenting signs and symptoms included paresis or paralysis (65%), paresthesias (40%), and myelopathy (40%). Perioperative embolization was performed in the majority (60%) of patients. Pial AVM resection was performed in 17 cases (85%). Angiographically verified AVM obliteration was achieved in 15 patients (75%). At a mean follow-up duration of 45.4 ± 52.4 months (range 2-176 months), 14 patients (70%) remained functionally independent (mRS and McCormick Scale scores ≤ 2). One perioperative complication occurred, yielding a surgical morbidity rate of 5%. Three symptomatic spinal cord tetherings occurred at a mean of 5.7 years after AVM resection. No neurological decline was observed after endovascular and surgical interventions. No deaths occurred. Long-term angiographic follow-up data were available for 9 patients (40%) at a mean of 67.6 ± 60.3 months (range 5-176 months) following AVM resection. Durable AVM obliteration was documented in 5 (83%) of 6 patients., Conclusions: Intramedullary AVMs may be safely resected with satisfactory clinical and angiographic results. The pial resection technique, which provides subtotal AVM nidus resection, effectively devascularized these lesions, as confirmed on postoperative angiography, without violating the spinal cord parenchyma, thereby potentially reducing iatrogenic injury.

Object: Frozen-section analysis is the current standard for the intraoperative diagnosis of brain tumors. Intraoperative confocal microscopy is an emerging technology with the potential to visualize tumor histopathological features and cell morphology in real time. The authors report their findings using this new intraoperative technology in vivo with sodium fluorescein contrast during the course of 50 microsurgical tumor resections., Methods: Eighty-eight regions were visualized with confocal microscopy, and corresponding biopsy samples were examined with routine neuropathological analysis. The tumors studied included meningiomas, schwannomas, gliomas of various grades, and a hemangioblastoma. The confocal microscopic features of each tumor and of various artifacts inherent to the technology were documented. A pathologist working in a blinded fashion reviewed a subset of the images in a further evaluation of the usefulness of the device as a diagnostic tool., Results: Overall, intraoperative confocal imaging correlated surprisingly well with corresponding traditional histological findings, including the identification of many pathognomonic cytoarchitectural features of various brain tumors. In the blinded study, 26 (92.9%) of 28 lesions were diagnosed correctly., Conclusions: Further study will be necessary for better definition of the role of intraoperative confocal microscopy as a routine adjunct for intraoperative brain tumor diagnosis.

Object: The purpose of this ongoing study is to compare the safety and efficacy of microsurgical clipping and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to determine if one treatment is superior to the other by examining clinical and angiographic outcomes. The authors examined the null hypothesis that no difference exists between the 2 treatment modalities in the setting of subarachnoid hemorrhage (SAH). The current report is limited to the clinical results at 1 year after treatment., Methods: The authors screened 725 patients with SAH, resulting in 500 eligible patients who were enrolled prospectively in the study after giving their informed consent. Patients were assigned in an alternating fashion to surgical aneurysm clipping or endovascular coil therapy. Intake evaluations and outcome measurements were collected by nurse practitioners independent of the treating surgeons. Ultimately, 238 patients were assigned to aneurysm clipping and 233 to coil embolization. The 2 treatment groups were well matched. There were no anatomical exclusions. Crossing over was allowed, but primary outcome analysis was based on the initial treatment modality assignment. Posttreatment care was standardized for both groups. Patient outcomes at 1 year were independently assessed using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score > 2 at 1 year. The primary outcome was based on the assigned group; that is, by intent to treat., Results: One year after treatment, 403 patients were available for evaluation. Of these, 358 patients had actually undergone treatment. The remainder either died before treatment or had no identifiable source of SAH. A poor outcome (mRS score > 2) was observed in 33.7% of the patients assigned to aneurysm clipping and in 23.2% of the patients assigned to coil embolization (OR 1.68, 95% CI 1.08-2.61; p = 0.02). Of treated patients assigned to the coil group, 124 (62.3%) of the 199 who were eligible for any treatment actually received endovascular coil embolization. Patients who crossed over from coil to clip treatment fared worse than patients assigned to coil embolization, but no worse than patients assigned to clip occlusion. No patient treated by coil embolization suffered a recurrent hemorrhage., Conclusions: One year after treatment, a policy of intent to treat favoring coil embolization resulted in fewer poor outcomes than clip occlusion. Although most aneurysms assigned to the coil treatment group were treated by coil embolization, a substantial number crossed over to surgical clipping. Although a policy of intent to treat favoring coil embolization resulted in fewer poor outcomes at 1 year, it remains important that high-quality surgical clipping be available as an alternative treatment modality.

Object: Schwannomas occupying the craniocervical junction (CCJ) are rare and usually originate from the jugular foramen, hypoglossal nerves, and C-1 and C-2 nerves. Although they may have different origins, they may share the same symptoms, surgical approaches, and complications. An extension of these lesions along the posterior fossa cisterns, foramina, and spinal canal--usually involving various cranial nerves (CNs) and the vertebral and cerebellar arteries--poses a surgical challenge. The primary goals of both surgical and radiosurgical management of schwannomas in the CCJ are the preservation and restoration of function of the lower CNs, and of hearing and facial nerve function. The origins of schwannomas in the CCJ and their clinical presentation, surgical management, adjuvant stereotactic radiosurgery, and outcomes in 36 patients treated at Barrow Neurological Institute (BNI) are presented., Methods: Between 1989 and 2009, 36 patients (mean age 43.6 years, range 17-68 years) with craniocervical schwannomas underwent surgical resection at BNI. The records were reviewed retrospectively regarding clinical presentation, radiographic assessment, surgical approaches, adjuvant therapies, and follow-up outcomes., Results: Headache or neck pain was present in 72.2% of patients. Cranial nerve impairments, mainly involving the vagus nerve, were present in 14 patients (38.9%). Motor deficits were found in 27.8% of the patients. Sixteen tumors were intra- and extradural, 15 were intradural, and 5 were extradural. Gross-total resection was achieved in 25 patients (69.4%). Adjunctive radiosurgery was used in the management of residual tumor in 8 patients; tumor control was ultimately obtained in all cases., Conclusions: Surgical removal, which is the treatment of choice, is curative when schwannomas in the CCJ are excised completely. The far-lateral approach and its variations are our preferred approaches for managing these lesions. Most common complications involve deficits of the lower CNs, and their early recognition and rehabilitation are needed. Stereotactic radiosurgery, an important tool for the management of these tumors as adjuvant therapy, can help decrease morbidity rates.

Background: Spinal dural arteriovenous fistulae (dAVFs), are lesions involving an aberrant connection between a radicular feeding artery and the venous system of the spinal cord at the dural sleeve of the nerve root. When rare dAVFs are occult on digitally subtracted catheter-based angiography, they present a diagnostic and therapeutic challenge., Objective: We report 3 cases of angiographically occult spinal dAVFs that were evaluated during surgery with indocyanine green (ICG) fluorescent microscope-integrated angiography., Methods: Three patients with clinical and magnetic resonance imaging features suggestive of a spinal dAVF but no abnormality on digital subtraction angiography underwent surgical exploration with the aid of microscope-integrated ICG videoangiography., Results: In all 3 cases, ICG identified the intradural vein draining the fistula, clearly distinguishing it from an artery or uninvolved medullary vein., Conclusion: ICG angiography can rapidly identify a draining vein as it enters the spinal canal even in dAVFs not identifiable on catheter-based digital subtraction angiography.

Background: Pediatric aneurysms are rare and complex to treat. Long-term angiographic and clinical data after microsurgical or endovascular therapies are lacking., Objective: To study the clinical and radiographic outcomes in aneurysms in pediatric patients treated with microsurgery., Methods: Between 1989 and 2005, 48 patients

Introduction: The CO2 laser has a long history in both experimental and clinical neurosurgery. However, its use over the past decade has been limited by its cumbersome design and bulky set-up of the micromanipulator. These limitations are amplified when it is used with the operating microscope. These restrictions are addressed by the Omniguide fiber, which delivers the beam through flexible hollow-core photonic bandgap mirror fibers and allows the laser to be wielded like any other surgical instrument., Methods: The attending neurosurgeon prospectively assessed the usefulness of the laser in its first 45 consecutive uses at our institution based on a scale of 1 to 5., Results: The series included 11 cavernous malformations, 14 meningiomas, 7 ependymomas, 3 metastases, 3 astrocytomas, and 7 miscellaneous lesions. The laser was set up 91 times and used in 45 cases. The Omniguide fiber failed 5 times. No adverse events involving patients or staff were associated with laser use. The mean utility score was 3.7 +/- 0.8 (range, 2-5). The laser was most helpful in debulking fibrous lesions too tough for ultrasonic aspiration and lesions adherent to delicate neurovascular structures. The laser was not helpful with highly vascular tumors., Conclusion: In our early experience, the Omniguide laser was very helpful in selected cases in resecting specific types of lesions without complications; we have added the device to our neurosurgical armamentarium.

Objective: We introduce a technique for performing a selective amygdalohippocampectomy (AH) through a minisupraorbital approach., Methods: A minisupraorbital craniotomy and an anterior selective AH were performed in 8 cadaver heads (16 sides). The anatomic specimens were analyzed, and the extent of resection of the hippocampus and amygdala was evaluated. Surgically relevant measurements were performed using anatomic specimens. An image-guided system was used to document the extent of the anterior AH. Laboratory data were used to support the clinical application of the technique., Results: The anterior route allowed removal of the amygdala and hippocampus, as confirmed by anatomic assessment. The image-guided system and anatomic evaluation confirmed that the amygdala and hippocampus can be accessed and removed through this route. The mean distance between the anterior aspect of the uncus and the tip of the temporal horn was 17.0 +/- 4.6 mm; the mean distance from the head of the hippocampus to the posterior border of the cerebral peduncles was 26.0 +/- 3.2 mm. Clinical application resulted in satisfactory removal of the amygdala and hippocampus., Conclusion: The anterior route for selective AH is a logical and straightforward approach to the mesial temporal lobe. Compared with other variations, it is less invasive and destructive, especially in terms of the fibers of the optic pathway, temporal stem, and lateral temporal neocortex.

Background: The callosomarginal artery (CMA), the main branch of the pericallosal artery, courses in or near the cingulate sulcus and gives rises to 2 or more major cortical branches. There is confusion about the artery best fitting the definition of "callosomarginal artery." Distal anterior cerebral artery aneurysms represent 1.5% to 9% of intracranial aneurysms, and most often occur at the origin of the CMA. The microsurgical anatomic features of the CMA, its relationship with the pericallosal artery, and clinical implications are presented., Methods: The origin, course, branching pattern, and diameter of the CMA and its branches and its relationship with the pericallosal artery were studied in 60 cerebral hemispheres, including cadaveric dissections and angiographic images., Results: The CMA was present in 93.3% of hemispheres studied and arose mainly from A3 (55.2%), a mean of 3.11 +/- 1.90 cm from the anterior communicating artery. The mean diameter of the CMA at its origin was 1.53 +/- 0.36 mm. The CMA ran 1.28 +/- 0.89 cm until its first branch, describing an anterior convex curve backward and upward (60.7%). An average of 3 lesser branches originated from the CMA. The most consistent branch was the posterior internal frontal artery (67.9%). The mean diameter of the CMA branches was 0.93 +/- 0.33 mm., Conclusion: These morphometric measurements can help neurosurgeons access lesions located in distal intracranial vessels. The vessel coursing the longest pathway in or near the cingulate sulcus and otherwise following Moscow's classic definition should be considered the CMA.

Purpose: Nonvestibular cranial nerve schwannomas (NVCNS) are relatively rare tumors. We evaluated our experience with radiosurgical and microsurgical treatment alone and in combination for the management of NVCNS., Methods: The charts of 62 patients with NVCNS who were treated between 1993 and 2005 at our institution were reviewed. Patients diagnosed with neurofibromatosis type 2 were excluded. The patients underwent microsurgery and/or radiosurgery treatment., Results: Trigeminal and jugular foramen schwannomas were the most common NVCNS tumors (n = 47), and the only two groups with sufficient numbers of patients to allow comparison of the three treatment approaches. In these two groups, the mean tumor volume was significantly higher in those who received combined therapy (8.59 +/- 2.29 cc), compared with radiosurgery (4.94 +/- 3.02 cc; p = 0.05) or microsurgery alone (5.38 +/- 3.23; p = 0.027). Patients who underwent radiosurgery alone were significantly older (67.7 +/- 13.3 years; p = 0.019) than those treated with microsurgery (55.3 +/- 13.7 years) or with both modalities (48.7 +/- 12.8 years). The Karnofsky Performance Scale scores were significantly higher (p < or = 0.05) at follow-up compared with baseline for all three treatment approaches. There was no significant change in the Glasgow Outcome scores before and after treatment., Conclusions: Microsurgery and radiosurgery can both be used to manage NVCNS tumors with excellent results. When treatment with either modality alone is not reasonable, tumors can be managed effectively with combined micro- and radiosurgery treatment.

Objective: To increase the extent of the depth of field and focal sharpness in highly magnified image series from cadaveric microneurosurgical anatomic study or live surgery photographs obtained with the operating microscope, providing a higher quality and more satisfactory photographic and imaging experience., Methods: We used a computer workstation, CombineZM software (Alan Hadley, United Kingdom, www.hadleyweb.pwp.blueyonder.co.uk/), an injected cadaver head specimen, and an operating microscope equipped with a digital single-lens reflex camera. Fifteen images were obtained of the dissection area through an anterior petrosal approach. The focus point was fixed to different points in each image. The images were loaded into CombineZM software for processing., Results: The stacking process of photographs with CombineZM freeware provides significant increase in extent of depth of field and wider area of image clarity, producing a sharp, high-quality image., Conclusion: An image processed from a stack of photographs from cadaveric microneurosurgical studies or from the operating microscope in live surgery can be rendered to show extended 3-dimensional depth of field and clarity. This method offers improvements for editing, displaying, and publishing neurosurgical anatomic images.

Objective: We retrospectively reviewed our experience treating third ventricular colloid cysts to compare the efficacy of endoscopic and transcallosal approaches., Methods: Between September 1994 and March 2004, 55 patients underwent third ventricular colloid cyst resection. The transcallosal approach was used in 27 patients; the endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of hydrocephalus were similar between the two groups., Results: The operating time and hospital stay were significantly longer in the transcallosal craniotomy group compared with the endoscopic group. Both approaches led to reoperations in three patients. The endoscopic group had two subsequent craniotomies for residual cysts and one repeat endoscopic procedure because of equipment malfunction. The transcallosal craniotomy group had two reoperations for fractured drainage catheters and one operation for epidural hematoma evacuation. The transcallosal craniotomy group had a higher rate of patients requiring a ventriculoperitoneal shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up demonstrated more small residual cysts in the endoscopic group than in the transcallosal craniotomy group (seven versus one). Overall neurological outcomes, however, were similar in the two groups., Conclusion: Compared with transcallosal craniotomy, neuroendoscopy is a safe and effective approach for removal of colloid cysts in the third ventricle. The endoscope can be considered a first-line treatment for these lesions, with the understanding that a small number of these patients may need an open craniotomy to remove residual cysts.

Objective: To compare anatomically the surgical exposure provided by pterional (PT), orbitozygomatic (OZ), and minisupraorbital (SO) craniotomies., Methods: Seven sides of six fixed cadaver heads injected with silicone were used. The mini-SO craniotomy followed by the PT and OZ approaches were performed sequentially. The bony flaps were attached with miniplates and screws, allowing easy conversion between the approaches. A frameless stereotactic device was used to calculate an area of surgical exposure and the angles of approach for six different anatomic targets. An image guidance system was used to demonstrate the limits of the surgical exposure for each technique., Results: No significant differences were observed in the total area of surgical exposure when comparing the mini-SO (A = 1831.2 +/- 415.3 mm), PT (A = 1860.0 +/- 617.2 mm), and OZ approaches (A = 1843.3 +/- 358.1 mm; P > 0.05). Angular exposure was greater for the OZ and PT approaches than for the mini-SO approach, either in the vertical and horizontal axes, considering all of the six targets studied (P < 0.05). Except for the distal segment of the ipsilateral sylvian fissure, no practical differences in the limits of the exposure were detected., Conclusion: The mini-SO approach may offer a similar surgical working area compared with that provided by standard craniotomies and constitutes an excellent alternative to the OZ and PT craniotomies in selected patients. Selection should not be based primarily on the area to be exposed, but rather on the working angles that are anticipated to be required. The key point is to use the most adequate technique for a particular patient, rather than using a one-size-fits-all approach for all patients.