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Even though neurosurgeons exercise these enormous and versatile skills, the COVID-19 pandemic has shaken the fabrics of the global neurosurgical family, jeopardizing human lives, and forcing the entire world to be locked down. We stand on the shoulders of the giants and will not forget their examples and their teachings. We will work to the best of our ability to honor their memory. Professor Harvey Cushing said: "When to take great risks; when to withdraw in the face of unexpected difficulties; whether to force an attempted enucleation of a pathologically favorable tumor to its completion with the prospect of an operative fatality, or to abandon the procedure short of completeness with the certainty that after months or years even greater risks may have to be faced at a subsequent session-all these require surgical judgment which is a matter of long experience." It is up to us, therefore, to keep on the noble path that we have decided to undertake, to accumulate the surgical experience that these icons have shown us, the fruit of sacrifice and obstinacy. Our tribute goes to them; we will always remember their excellent work and their brilliant careers that will continue to enlighten all of us.

Background Several diseases that involve the optic canal or its contained structures may cause visual impairment. Several techniques have been developed to decompress the optic nerve. Objective To describe minimally invasive extradural anterior clinoidectomy (MiniEx) for optic nerve decompression, detail its surgical anatomy, present clinical cases, and established a proof of concept. Methods Anatomic dissections were performed in cadaver heads to show the surgical anatomy and to show stepwise the MiniEx approach. In addition, these surgical concepts were applied to decompress the optic nerve in 6 clinical cases. Results The MiniEx approach allowed the extradural anterior clinoidectomy and a nearly 270° optic nerve decompression using the no-drill technique. In the MiniEx approach, the skin incision, dissection of the temporal muscle, and craniotomy were smaller and provided the same extent of exposure of the optic nerve, anterior clinoid process, and superior orbital fissure as that usually provided by standard techniques. All patients who underwent operation with this technique had improved visual status. Conclusions The MiniEx approach is an excellent alternative to traditional approaches for extradural anterior clinoidectomy and optic nerve decompression. It may be used as a part of more complex surgery or as a single surgical procedure.

Rhino-cerebral mucormycosis is a rare fulminant fungal infection, that mostly occurs in individuals with committed immunity. The delay caused by late occurrence of cerebral manifestations led to poor prognosis. The treatment involves aggressive surgical therapy, with repeated debridement, in combination with intravenous anti-fungic therapy. We describe a case of microsurgical resection of rhino-cerebral mucormycosis with cavernous sinus extension and internal carotid thrombosis. Informed written consent was obtained from the patient. A 41-year-old patient, with diabetes mellitus was admitted at a nearby hospital for frontal headache and nasal congestion. Computed tomography scan showed diffuse sinusitis. Endoscopic endonasal debridement of the paranasal sinuses was performed. Patient was then transferred to our institution. After one day of treatment, patient developed left sided hemiplegia and worsening of periorbital swelling. Magnetic resonance image depicted hyperintense signal changes in the right orbit, ethmoidal and maxillary sinus, partial thrombosis of the right cavernous sinus and internal carotid artery, and right fronto-parietal ischemia. Debridement of the ethmoidal, maxilla and sphenoidal sinus, associated with right eye enucleation were performed. Histopathological examination revealed the presence of mucormycosis. Serial MRI imaging studies after day 40 showed increased extension of inflammatory changes in the right cavernous sinus and increased mass in the right trigeminal nerve, thrombosis of the right internal carotid artery and subacute cerebral infarcts. Because of the persistence of the infection the patient underwent extradural and subdural microsurgery resection of mucormycosis collection in the right cavernous sinus. During the follow-up she gradually improved and was discharged on an ambulatorial regimen.

Objective Sphenopetroclival (SPC) meningiomas are considered among the most complex skull-base neoplasms to approach surgically. We aim to determine whether some SPC meningiomas can be safely and effectively treated using a modified minimally invasive pterional posterolateral transcavernous-transtentorial approach (MIPLATTA). Methods Fourteen patients harboring SPC meningiomas were surgically treated through a MIPLATTA. MIPLATTA includes a minipterional craniotomy, anterior extradural clinoidectomy, peeling of the temporal fossa, decompression of cranial nerves (CNs) in the cavernous sinus, and sectioning of the tentorium to reach the upper part of the posterior fossa. Results Gross total resection was achieved in 11 of 14 patients (78%), whereas near-total resection was accomplished in the other 3 patients (22%), each of whom underwent a further complementary retrosigmoid approach for gross total tumor resection. There were no deaths, and 13 of 14 patients were independent at 6 months follow-up (modified Rankin Scale score ≤2). One patient had pontine infarction after the procedure and experienced moderate disability at follow-up (modified Rankin Scale score 3). All patients had some degree of CN impairment. Of 38 cranial neuropathies, 15 (39%) improved, 20 (53%) remained stable, and 3 (8%) worsened postoperatively. Four new CN deficits were observed postoperatively in 3 patients (fourth CN, 2 patients; third CN, 1; fifth CN, 1). Conclusions MIPLATTA is a useful and safe treatment alternative that allows resection of large SPC tumors with dominant invasion of cavernous sinus and middle fossa, preserves hearing and facial motor function, and provides good chances of recovery of visual and oculomotor deficits.

The study of cerebrovascular anatomy can be difficult and may take time due to its intrinsic complexity. However, it can also be difficult for the following reasons: the excessive description of neuroanatomy making articles hard to read, the unclear clinical application of what is written, the use of simplified or intricate schematic drawings that are not always appropriate for effective teaching, the poor quality of neuroanatomy dissections and the use of unusual views of figures that are not strictly related to the most frequent neuroimages to be interpreted in daily practice. Because of this, we designed an article that incorporates original and accurate anatomical dissections in an attempt to improve its comprehensibility. Five formalin-fixed adult cadaveric heads, whose vessels were injected with a colored silicone mixture (red for arteries and blue for veins), were dissected and examined under a microscope with magnifications from 3× to 40×. Special emphasis has been placed on correlating topographic anatomy with routine neuroimaging studies from computed tomographic angiography (CTA) and digital subtraction angiography (DSA). The essential surgical anatomy in a neurosurgeon’s daily practice is also described. The cadaveric dissections included in this study contribute to the understanding of the cerebrovascular anatomy necessary for the neurosurgeon’s daily practice.

Background: The clinical applicability of the minipterional (MPT) craniotomy is still limited to small and superficial anterior circulation aneurysms. We discuss the technical nuances of a modified MPT approach, the extradural MPT approach (eMPTa), for the treatment of a giant intracranial aneurysm (GIA) arising from the paraclinoid carotid artery. Case Description: A 44-year-old female presented with facial hypoesthesia and third cranial nerve palsy. Further investigations revealed the presence of a 27 mm aneurysm arising from the communicating segment of the internal carotid artery. The patient underwent surgical clipping through an extradural MPT craniotomy and combined anterior clinoidectomy. Postoperative angio-computed tomography demonstrated complete aneurysm occlusion and patency of the parent vessels. The patient recovered fully from her previous deficits. Conclusion: The skull base drilling, interdural dissection, and anterior clinoidectomy are key steps during the eMPTa that optimizes the use of the extradural corridor. Such adaptations are enough to improve the surgical maneuverability along the paraclinoid region and adapt the MPT suitability for the treatment of complex GIA.

Introducción: Las lesiones arteriales aneurismáticas cobran gran relevancia hoy en día ya que si se realiza un diagnóstico precoz se puede prevenir la rotura de las mismas. Aneurisma no roto o grado 0 se define a aquel que no sangro. El riesgo de tener una HSA de un aneurisma no roto es de aproximadamente 1,5% anual, acumulable. En el caso de lesiones grandes o gigantes como nuestro caso ese riesgo aumenta mucho porcentualmente, y aneurismas disecantes hasta 40%. Materiales y Métodos: En primer lugar se presenta caso clínico de una paciente que fue asistida en el Hospital Maciel, donde se estudia y opera de un aneurisma fusiforme mediante clipado, progresando la enfermedad requiriendo tratamiento endovascular y posteriormente exéresis asociada a bypass extra-intracraneano con injerto radial para lograr la curación del mismo. A partir de este caso clínico ilustrativo se realizó una puesta al día sobre esta patología. Discusión: Se discute la clasificación de aneurismas, etiología, opciones terapéuticas y el seguimiento de estos pacientes. Conclusiones: En caso de los aneurismas fusiformes debemos sospechar una base disecante, lo cual es importante para definir el tratamiento de estas lesiones.

The minipterional craniotomy (MPTc) has been widely accepted as a minimally invasive alternative to the pterional approach for the treatment of certain small non-ruptured anterior circulation aneurysms. The aim of this study was to determine the effectiveness and safety of the MPTc in the context of a complex and potentially harmful scenario: acute onset of subarachnoid hemorrhage (SAH) in patients harboring multiple intracranial aneurysms (MIA).Patients harboring MIA clipped through a unilateral MPTc were selected from four retrospective databases of four high-volume neurosurgical centers. Patients with a HuntHess score 4 or 5 were not considered candidates for clipping through a MPTc. Medical records and radiological images were retrospectively reviewed. Epidemiological, clinical and radiological data, as well as short-term outcome (modified Rankin scale at 6 month-follow-up) were analyzed.16 patients harboring 33 aneurysms (16 ruptured, 17 non ruptured) met the inclusion criteria. Each aneurysm size was 5.7 ± 2.1 mm (range 3-11). 12 out of 33 aneurysms were located in the middle cerebral artery (MCA). Anterior communicating (ACom) and MCA aneurysms were the aneurysm locations most commonly ruptured (5 each, 62 %). Complete occlusion was achieved in 32 aneurysms (97 %) and near-complete occlusion in 1 (3%). 13 patients (93 %) were independent at 6 month-follow-up. Mortality rate was 0%. Complications included 1 cerebrospinal-fluid leakage.When indicated (Hunt Hess4), performing a MPTc is safe and effective in aSAH cases with multiple aneurysms.

Saphenous vein high-flow bypass for complex aneurysms: technical aspects anti surgical results The vascular reconstruction technique for complex cerebral aneurysms utilizing high-flow venous bypass is presented The indications, complications, and results in a series of 27 patients operated on during the period between 1992 and 1997 are discussed. Seventy-one percent of the patients had giant intracavernous carotid aneurysms. Five patients underwent venous bypasses as a prophylatic means against intraoperative ischemia in the treatment of giant supraclinoid aneurysms. Seventy-five of our bypasses were patent at the post-operative angiogram. Our clinical results were good in 85, 7% of the patients with 3,6% ischemic morbidity and 7,1% non-ischemic morbidity; the overall mortality was 3,6%.

Objective Sphenopetroclival meningiomas (SPCMs) represent a challenge for surgical treatment. The authors used an objective volumetric analysis to assess the effect of the grade of resection and different surgical strategies that may affect the outcome of this tumors. Methods Over a period of 4 years, patients with SPCMs were treated using a middle versus posterior fossa approach, or a two-stage surgery combining both approaches, based on the tumor location in relation to the petrous ridge and tumor volume. Retrospectively, all cases were analyzed with regard to tumor volume, extent of resection (EOR), functional outcome, and complications. Results Twenty-seven patients with SPCMs met the inclusion criteria, and the mean follow-up was 24.8 months. Eleven patients underwent a two-stage surgery, while 16 patients had their SPCMs resected via a single craniotomy. Mean EOR was 87.6% and gross total resection was achieved in 48% of patients. Patients with greater EOR had better functional outcomes (r = 0.81, p Conclusion Staging of the surgical resection of larger tumors may lead to greater EOR, and this strategy should be considered for larger tumors.

Clipping continues to be one of the treatment strategies for ophthalmic artery aneurysms not amenable for stenting or coiling, or when long-term treatment durability is a concern. However, crescent development of endovascular techniques demands minimal invasiveness in the transcranial approaches while ensuring satisfactory results. We describe an extradural micropterional keyhole approach (eMKA) to the paraclinoid region and highlight the key anatomical elements of this surgical approach. The eMKA is a minimally invasive approach that provides access to the paraclinoid region using an extradural corridor. Therefore, it is suitable for clipping of ophthalmic artery aneurysms and other paraclinoid aneurysms.

Minipterional (MPT) craniotomy has recently been added to the neurosurgical armamentarium as a less invasive alternative to the pterional craniotomy for the treatment of parasellar lesions. However, its clinical applicability in the treatment of certain complex aneurysms, such as those arising in the paraclinoid region, remains unclear. To illustrate the microsurgical anatomy of a modified extradural MPT approach, which combines a classic MPT craniotomy with an extradural anterior clinoidectomy, and to demonstrate its clinical applicability in the treatment of complex paraclinoid aneurysms. A stepwise extradural MPT approach is illustrated in a cadaver study. Clinical outcome data from a series of 19 patients with 20 paraclinoid aneurysms treated surgically using the extradural MPT approach between 2016 and 2018 were retrospectively collected. In 95% of the cases, complete aneurysm occlusion was achieved. No aneurysm recurrences were seen during follow-up with a median length of 21 months. The outcome, according to the modified Rankin Scale, was 0 points in 12 patients (63%), 1 point in 6 patients (32%), and 2 points in 1 patient (5%). Four out of 6 patients (67%) with initial visual symptoms showed improvement following treatment, whereas in two (11%), vision became worse. The extradural MPT approach ensures a sufficiently large exposure of the paraclinoid region that is comparable with conventional approaches with the advantage of being minimally invasive. Our case series demonstrates the feasibility of this approach for the treatment of complex paraclinoid aneurysms.

Cavernous sinus and petroclival region is an anatomically complex region in close relationship with important neurovascular structures. As such, the surgical treatment of spheno-petro-clival (SPC) meningiomas represents an operative challenge, in which several routes and its combinations might be used. We describe in detail the surgical technique of the extradural minipterional pretemporal approach (eMPT-P) to the SPC region and highlight the main anatomical key elements involved in this approach as well as the technical aspects for avoiding surgical complications. The eMPT-P is a versatile approach that uses the extradural route, and thereby reduces brain retraction, while provides a good angle of exposure of the SPC region.

Clipping and coiling are currently the two alternatives in treatment of ruptured cerebral aneurysms. In spite of some meritorious analysis, further discussion is helpful to understand the actual state of art. Retreatment and rebleeding rates clearly favors clipping, although short-term functional outcome seems to be beneficial for clipping, while this different is not such if we perform the comparison at a longer follow up. Long-term follow ups and cost analysis are mandatory to have a clear view of the current picture in treatment of subarachnoid hemorrhage. Treatment strategy should be made by a multi-disciplinary team in accredited centers with proficient experience in both techniques. Fil: Martinez-Perez, Rafael. Universidad Austral de Chile; Chile Fil: Rayo, Natalia. Western University; Canadá Fil: Montivero, Agustin. Instituo de Neurocirugía Dr Alfonso Asenjo; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Farmacología Experimental de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Farmacología Experimental de Córdoba; Argentina Fil: Mura, Jorge Marcelo. Instituo de Neurocirugía Dr Alfonso Asenjo; Chile

Giant middle cerebral artery (MCA) aneurysms are rare complex cerebrovascular lesions to treat.1 The management of those aneurysms may be very challenging, despite the introduction of refined microsurgical techniques and the rapid progress in endovascular methods, which often require bypass surgery as part of the strategy.2-4 This approach is particularly relevant to giant, dolichoectatic, and thrombotic aneurysms.5,6 This video shows the surgical strategy and stepwise depiction of the surgical treatment of a complex giant thrombosed aneurysm using a double-barrel superficial temporal artery (STA) to MCA bypass (Video 1). Informed written consent was obtained from the patient and his family. The patient was a 50-year-old man, previously healthy, who presented with headache, memory difficulty, and left-sided involuntary movements for 2 months. Computed tomography scan showed a giant round calcified and heterogeneous lesion compatible with a thrombosed MCA aneurysm. Brain magnetic resonance imaging showed the same lesion with a flow void signal inside in a serpentine fashion and a complete hemosiderin halo. Conventional angiography showed the false lumen and the filling of the distal MCA branches with a certain degree of arterial delay. The lesion was located between M1 and M3 segments of MCA. Extracranial-intracranial STA-MCA bypass was performed. Then we opened the aneurysm sac for decompression and observed the lenticulostriate artery branches arising away from the aneurysm sac. The complete clipping and patency of the anastomosis was validated during surgery by indocyanine green angiography. Postoperative cerebral computed tomography angiography revealed good patency from the STA to the MCA. The patient was neurologically intact without complains.

Background: In this paper, we report a clinical series of skull base lesions operated on trough the MiniPT, extending its application to skull base lesions, either using the classical minipterional or a variant, we call extradural minipterional approach (MiniPTEx). Methods: We describe our surgical technique of operating on complex skull base lesions using a minipterional extradural approach. Anterior clinoidectomy, middle fossa peeling, transcavernous, and Kawase approaches were performed as needed. In total, we carried out 24 surgeries: three skull base tumors, 1 Moyamoya case, and 20 giant/complex intracranial aneurysms. All the patients present good neurological result (mRs < 3). Only two patients had paralysis of any cranial nerve and only one patient had a mild hemiparesis. Results: This surgery series there are 24 cases, 10 patients were treated with exclusive MiniPT. MiniPT extradural approach was made in 14 patients. Twelve were treated using pure MiniPTEx approach, 1 patient using transcavernous approach, and in 1 patient, the anterior clinoid was resected with the combination of a MiniPT, a medium fossa peeling, and the Kawase anterior petrosectomy for skull base surgery. Conclusion: We further advance the indications of the MiniPT by extending it to operate on the cranial base tumors or complex vascular lesions without additional morbidity. MiniPT approach may be safely associated with skull base techniques, including anterior and posterior clinoidectomies, peeling of the middle fossa, transcavernous approach, and anterior petrosectomy. The versatility of the MiniPT craniotomy and the feasibility of performing skull base surgery through the MiniPT technique have been demonstrated in this paper.

Ophthalmic trunk aneurysms associated with other vascular malformations are extremely rare, and little is known regarding its natural history and options of treatment. Case Description: We present the interesting case of a 51-year-old man who was admitted with progressive visual loss secondary to a concurrent fusiform ophthalmic trunk aneurysm associated with a dural arteriovenous fistula. He was treated with transarterial embolization of the fistulous point. Conclusions: A follow-up angiogram at 6 months showed complete obliteration of the dural arteriovenous fistula and regression of the ophthalmic trunk aneurysm. The literature is reviewed, and potential pathophysiologic mechanisms leading to this association and regression in this subgroup of aneurysms are discussed. Fil: Martínez-Pérez, Rafael. Universidad Complutense de Madrid; España. Universidad de Chile; Chile Fil: Tsimpas, Asterios. Advocate Illinois Masonic Medical Center; Estados Unidos Fil: Ruiz, Álvaro. Universidad de Chile; Chile Fil: Montivero, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Farmacología Experimental de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Farmacología Experimental de Córdoba; Argentina Fil: Mura, Jorge. Universidad de Chile; Chile

Background: Functional recovery after aneurysmal subarachnoid hemorrhage (SAH) remains a significant problem. We tested a novel therapeutic approach with long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) to assess the safety and feasibility of an effectiveness trial. Methods: We conducted a multicentre, parallel, randomized, open-label pilot trial. Patients admitted within 72 hours after SAH with modified Fisher scale scores of 3 or 4 who were selected for scheduled aneurysm clipping were allocated to receive either n-3 PUFA treatment (parenteral perioperative: 5 days; oral: 8 weeks) plus usual care or usual care alone. Exploratory outcome measures included major postoperative intracranial bleeding complications (PIBCs), cerebral infarction caused by delayed cerebral ischemia, shunt-dependent hydrocephalus, and consent rate. The computed tomography evaluator was blinded to the group assignment. Results: Forty-one patients were randomized, but one patient had to be excluded after allocation. Twenty patients remained for intention to treat analysis in each trial arm. No PIBs (95% confidence interval [CI]: 0.00 to 0.16) or other unexpected harm were observed in the intervention group (IG). No patient suspended the intervention due to side effects. There was a trend towards improvements in all benefit-related outcomes in the IG. The overall consent rate was 0.91 (95% CI: 0.78 to 0.96), and there was no consent withdrawal. Conclusions: Although the balance between the benefit and harm of the intervention appears highly favourable, further testing on SAH patients is required. We recommend proceeding with amendments in a dose-finding trial to determine the optimal duration of parenteral treatment.

Background Mild hearing loss following shunting has been described; however, severe auditory impairment associated with ventriculoperitoneal (VP) shunt is an uncommon, rarely reported phenomenon. Treatment options and pathophysiologic considerations are discussed in this case report. Case Description A 27-year-old man who was treated for an eighth cranial nerve schwannoma with complete resection and a VP shunt 10 years previously presented to the emergency department with acute severe hearing loss and headache. Imaging showed diminished size of the ventricles and dural contrast enhancement. The previous shunt was replaced with a programmable antisiphoning VP shunt. The patient's hearing and headache improved 48 hours later, as demonstrated in serial audiograms. Conclusions Hearing loss is an underestimated complication of shunting that in some cases may progress to severe impairment and deafness. Patients with a VP shunt who experience hearing loss should undergo further evaluation and possibly adjustment of shunt settings.

Objective This study sought to show and analyze the main authors' experience (P.R. and J.M.C.) in previously coiled aneurysm surgery as an emerging challenge in today's neurosurgical practice. Methods Twelve female and 8 male patients, whose ages ranged from 32 to 56 years (average 43.5), underwent surgery between April 2009 and September 2012 in 2 centers. Reasons for surgery were 13 partially occluded aneurysms and 7 recanalized aneurysms. Results There was no mortality in this series. Aneurysmal sites were 5 anterior communicating artery aneurysms, 5 posterior communicating artery aneurysms, 3 middle cerebral artery aneurysms, 6 paraclinoid carotid artery aneurysms, and 1 aneurysm in the pericallosal artery. A patient sustained a postsurgical frontal infarction with mild neurological deficit. One of the aneurysms presented with an arterial branch at the level of the aneurysmal neck; therefore, partial clipping and packing was required. Microsurgical clipping in the remaining patients was performed successfully. Eight cases required partial coil removal before clipping. Conclusions Surgical management of previously coiled aneurysms is an emerging challenge in neurosurgery. Incomplete or ineffective embolizations pose an increased risk for the patient, thus requiring surgical treatment. Although not advisable, coil removal might be necessary when in the vicinity of the aneurismal neck in order to place the clip correctly. The authors believe that adequate patient selection and careful preoperative planning are essential to reduce the incidence of patients with unsuccessful coils who will later need surgical treatment.

Background Cardiac myxoma is the most common cardiac tumor. Neurologic complications are seen in 20%-35%, most frequently embolic ischemic stroke, and rarely secondary to intracranial aneurysms. The mechanism of aneurysm formation in these patients is speculative. Methods We report, herein, a 37-year-old male with a cardiac myxoma who experienced repeated ischemic stroke and intracerebral hematoma despite resection of heart tumor, secondary to multiple cerebral aneurysm. Results We offered him surgery with a bypass and clipping, because growing of aneurysm was not suitable for endovascular treatment. Conclusion Bypass and clipping are possible options in this type of disease. Aneurysm biopsy supports mycotic theory of aneurysm formation.

This article is the second of two parts. Cerebral revascularization procedures regained popularity during the past few years. They have been used routinely to treat patientswith giant unclippable aneurysms and complex cranial base lesions. Furthermore, recent evidence has shown that a specific group of patients with ischemic cerebrovascular disease could benefit from low-flow or highflow bypass. Improvement in surgical techniques, with consequent decrease in morbidity and mortality associated with high-flowbypass for giant unclippable aneurysms, revitalized the question as to whether patients with indications for internal carotid artery (ICA) occlusion should be universally revascularized. Part I of this article discussed patient selection and surgical technique for extracranial-intracranial (EC-IC) bypass. In part II, we discuss graft selection and a universal versus selective revascularization approach.After reading this article, the neurosurgeon should be able to describe how to choose appropriate grafts for patients undergoing extracranial-intracranial bypass and explain the benefits and risks associated with use of a universal versus selective revascularization approach. The development of EC-IC bypasswas subsequent to the application of surgical microscope to neurosurgery. In 1962, Julius Jacobson (a general vascular surgeon) and Donaghy were the first to describe a microsurgical procedure in neurosurgery. In 1965, Yasargil went to study at Donaghy’s laboratory in Vermont. Their diligent work improved the pioneering bypass techniques of Suarez and Jacobson. In 1972, Yasargil performed the first superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in a patientwith moyamoya disease.Meanwhile, many other neurosurgeons were developing alternative bypass techniques. In the 1970s, Sundt and Ausman introduced posterior circulation revascularization. Lougheedwas the first to use a great saphenous vein (GSV) in an EC-IC bypass, followed byAusman in 1978, who used a radial artery (RA) graft. Since then, much of the technique has improved as have anesthetic techniques, ICU Basic Aspects of High-Flow Extracranial-Intracranial Bypass: Part II

Jorge Mura, M.D. performed the microsurgery presented in this report on August 22, 2006 at the Institute of Neurosurgery Asenjo in Santiago, Chile. A highly vascularized tumor was present in the patient's only functional vertebral artery. Intraoperative neuromonitoring was conducted throughout the procedure. Following resection of the tumor and completion of the vertebral artery microanastomosis, somatosensory evoked potentials were improved from baseline potentials. Motor function was stable throughout the procedure. A post-operative computerized tomography (CT) angiogram showed that the reconstructed artery was normal and three times the size of the right vertebral artery. The patient had no post operative deficits. The preliminary result of the biopsy was an angiofibroma.

Objective To describe the use of the superior thyroid artery as a donor vessel in extracranial-intracranial (EC-IC) revascularization when a “low-flow” bypass is required and the superficial temporal artery is not available. Design Case report. Setting University hospital. Participants Four cases. Main Outcome Measures Postoperative course after EC-IC bypass surgery. Results In case 1, the parent vessel was occluded postoperatively. The radial bypass was sufficient to replace the internal carotid artery (ICA) flow, and a prophylactic was turned into a definitive bypass. In case 2, the superior thyroid artery was used because the radial artery was not long enough to reach the external carotid artery. The recipient vessel was modified from the middle cerebral artery to the ophthalmic segment of the ICA. In case 3, the graft was occluded after surgery because of carotid artery reconstruction. In case 4, after surgery/radiotherapy for meningioma, the patient developed wound dehiscence and was reoperated for bypass occlusion. The graft was weak and bled intraoperatively, without infarction. The three first patients are intact, and the fourth remains disabled (Glasgow Outcome Scale: 3; Rankin Scale: 5). Conclusion The superior thyroid artery was adequate for proximal anastomosis in EC-IC procedures in the situations described.

Vestibular Schwannomas (VS) are benign intracranial tumors, for which their current management is a matter of debate, although microsurgical treatment remains the mode of choice in the majority of cases.To describe the surgical outcome of patients operated on for a VS in a Chilean Public Hospital.A series of 67 patients treated surgically between 2002 and 2012, in the Institute of Neurosurgery Asenjo is presented.Sixty-five cases (97%) corresponded to Koos III and IV tumors, of which 52% were large (3-4 cm) or Giant (4 cm). Forty-one cases were operated on using a retrosigmoid transmeatalapproach (61%). Total resection was achieved in 97% of the cases and subtotal in the remaining 3%. A mean six months follow-up showed that good facial function (House-Brackmann I or II) was obtained in 32.7% of the patients, and moderate function (House-Brackmann III or IV) in 42.3%. Cardiopulmonary complications were the most frequent (28%), and mortality was 1.5%.The VS are tumors that can cause significant neurological deficit in advanced stages, despite their benign nature. Surgical treatment is very complex, and must be performed by specialized teams to ensure optimal functional results.

Background There is no satisfactory medical treatment for hydrocephalus and most often surgical treatment is necessary, including shunting or endoscopic third ventriculostomy (ETV), both with their well-known advantages and drawbacks. The objective of this study is to describe a contemporary series of anterior ventriculocisternostomy. Patients Twenty-two patients with hydrocephalus treated at two institutions between 2005 and 2009 were presented. The authors employed a technique called anterior ventriculocisternostomy to treat selected cases. This technique includes supraciliary incision, small craniotomy, and fenestration of the lamina terminalis and Liliquist membrane. Hydrocephalus was secondary to hemorrhage from arteriovenous malformation (3 cases), spontaneous subarachnoid hemorrhage (2 cases), posterior fossa tumors (4 cases), head injury (1 case), basilar aneurysm (1 case), and posterior fossa hemorrhage (1 case). Eight patients had a normal-pressure hydrocephalus syndrome and one patient a slit ventricle syndrome. Aqueduct obstruction was noticed in one patient. Patients were followed up for 20.2 months (range: 10 to 46 months). Results No hemorrhagic complications or parenchymal injury were observed. One cerebrospinal fluid leakage occurred. No infection, mortality, and neurological morbidity were reported. Improvements were noticed in 18 cases. Eighty-two percent of the patients remained independent of shunt. Conclusion Anterior ventriculocisternostomy integrates old views of open ventriculocisternostomy with contemporary concepts of minimally invasive neurosurgery. It provides the most straightforward anatomical and physiological alternative to treat many types of hydrocephalus with no significant morbidity. Compared with conventional procedures, it has several advantages. This procedure is an important option to manage hydrocephalus and constitutes a safe, effective, and relatively inexpensive alternative to ETV and shunts.

Computational Structural Dynamics (CSD) simulations, Computational Fluid Dynamics (CFD) simulation, and Fluid Structure Interaction (FSI) simulations were carried out in an anatomically realistic model of a saccular cerebral aneurysm with the objective of quantifying the effects of type of simulation on principal fluid and solid mechanics results. Eight CSD simulations, one CFD simulation, and four FSI simulations were made. The results allowed the study of the influence of the type of material elements in the solid, the aneurism’s wall thickness, and the type of simulation on the modeling of a human cerebral aneurysm. The simulations use their own wall mechanical properties of the aneurysm. The more complex simulation was the FSI simulation completely coupled with hyperelastic Mooney-Rivlin material, normal internal pressure, and normal variable thickness. The FSI simulation coupled in one direction using hyperelastic Mooney-Rivlin material, normal internal pressure, and normal variable thickness is the one that presents the most similar results with respect to the more complex FSI simulation, requiring one-fourth of the calculation time.

Dear Editor, The authors present the named “unilateral subfrontal approach” for anterior communicating aneurysms, analyzed in a small clinical series. The authors present this approach mainly as an alternative to the pterional approach. This approach was previous described as the “superciliar keyhole approach” or the “lateral supraorbital approach” for the treatment not only of vascular disease but also for tumors.[2] The authors present their approach as a “tailored” pterional approach. Nevertheless, there are some aspects that are subject of criticism as the rutinary use of external ventriculostomy or lumbar drainage; these are procedures that carry additional risks: Intraoperative rebleeding, frontal lobe lesion among others. We strongly recommend the microsurgical wide opening of the basal cisterns and the fenestration of the lamina terminalis to obtain CSF drainage and brain relaxation during the surgery, we do not see the silvian fissure opening as an additional source of complications as the authors pointed out. Additionally, these microsurgical simple procedures are implicated in the prevention of the hydrocephalus and vasospasm in the subarachnoid hemorrhage secondary to ruptured aneurysms.[1] The four advantages that the authors provided are at least uncertain. In the number 4 we can say that the pterional approach provide a corridor to see up to the contralateral middle cerebral artery bifurcation. Another important issue is that they have a 50% of resection of the gyrus rectus in unruptured and 61% in ruptured aneurysms, so the approach does not avoid this designed resection of the frontal lobe; we only use a small gyrus rectus resection in the anterior communicating artery (ACoA) aneurysms superiorly projected located between the two A2 segments, especially in the large or giant lesions, in all the other cases we split the interhemispheric cistern, which is possible using the pterional approach. The authors point out that the pterional approach leave a cosmetic defect at the level of the pterion, but in their own series the leave two burr holes in the frontal bone visible in the forehead. Salma et al.[3] recently published a cadaveric anatomical study comparing this two approaches, in their paper they analyzes the qualitative and quantitative anatomic evaluation between this two approaches, showing that this kind of approach can eventually reduce the temporalis muscle trauma, and offers and equivalent access and exposure of the anterior communicating artery complex, optic nerve, optic chiasm, and sellar areas. However, like all the anatomical cadaveric models, they do not consider the role of the cisternal and ventricular opening using these anatomical corridors as the natural pathways to reach the pathology, in this case ACoA aneurysms. We think that in patient's ruptured aneurysms with hematoma or subarachnoid hemorrhage (SAH) of high Fisher grade this approach is not a good choice, because it does not allow a wide opening of the sylvian fissure for cleansing the blood clots and relaxing the brain. Hence, this approach would be useful just for treating the aneurysm, but not to deal with the SAH, without reducing neither the risk of vasospasm nor the hydrocephalus.

Intracranial aneurysm in the pediatric population is very rare; the prevalence has been reported from 0.5% to 4.6% [1–3]. This pathology is completely different from aneurysms in adults: gender predominance; location of aneurysm; incidence of spontaneous thrombosis; incidence of giant, dissecting, and fusiform aneurysm; and rate of subarachnoid hemorrhage, among others [4]. Different multidisciplinary approaches have been used, ranging from conservative follow-up to the most complex microsurgical and endovascular treatments. In the microsurgical group, there are different alternatives, direct clipping and reconstruction or trapping with bypass from extracranial–intracranial (EC–IC) or intracranial–intracranial (IC–IC) types. For the middle cerebral artery aneurysms, the revascularization is an excellent option, especially for the giant lesions in which the reconstruction is not an option. Even more, if we analyze this subject, the overall complication rate of EC–IC procedures is very low, and the 10-year patency rate is as high as 73% [5]. Different types of graft used in children have been reported for EC–IC bypasses with vein graft [5], with radial artery graft [2], and superficial temporal artery (STA) [2, 6]. In the pediatric group, the youngest patient previously reported with an EC–IC bypass with STA–middle cerebral artery (MCA) for a MCA aneurysm had 11 years [6]. We present our case report as the youngest patient ever treated with a combination of trapping with a successful STA–MCA bypass in a giant MCA aneurysm.

La acromegalia es una enfermedad cronica causada en la mayoria de los casos por un adenoma hipofisario. Su manejo es complejo por la gran variabilidad de la lesion causante y su repercusion clinica. Los resultados quirurgicos son pobres, con tasas de remision de la enfermedad en promedio de un 80% en microadenomas y 50% en macroadenomas. Se presenta la experiencia del autor en el manejo de esta patologia en 38 pacientes, los resultados de remision de la enfermedad. Se discute las alternativas de manejo, complicaciones asociadas y se ilustra con un caso clinico para demostrar las opciones terapeuticas en los casos mas complejos.

The walls of the blood vessels involved with cerebral aneurysms present different mechanical properties, when compared with those of normal artery. Consequently the models which may describe then predict an aneurysm rupture need as input their mechanical properties. This paper describes the experimental determination of the mechanical properties of the tissues of the blood vessels affected with a cerebral aneurysm. In particular, we determine and discuss the critical elongation and the rupture strength. The affected tissues were obtained from surgical clipping and extraction; six specimens were tested. The mechanical tests were performed in a tensile device. The experimental data was fitted numerically with a Mooney–Rivlin hyper elastic model. The model was compared with previous published data.

We discuss revascularization techniques for complex skull base lesions utilizing high-flow arterial bypass. At present, the radial artery is the donor graft utilized in most circumstances at our institution. The knowledge of revascularization techniques is very important to achieve radical resection in lesions where arterial compromise is documented.