Bone anatomic variations of the parasellar region and its technical implications in para clinoid and posterior communicating segment aneurysms microsurgical clipping - Technical note.

Background: Microsurgical treatment of paraclinoid aneurysms is a complex task that generally requires anterior clinoid process (ACP) removal to obtain adequate surgical exposure. This procedure poses a considerable technical difficulty due to the association of the ACP to critical neurovascular structures. Furthermore, anatomical variations in the parasellar region, such as the caroticoclinoid foramen (CCF) or an interclinoid bridge (ICB), may impose additional challenges and increase surgical complications. The present study aims to briefly review some anatomic variations in the parasellar region and describe a step-by-step surgical technique for a hybrid anterior clinoidectomy based on the senior author's experience. Methods: We present two cases with bone variations on the parasellar region in patients with a paraclinoid aneurysm and another with a posterior communicating segment aneurysm treated by microsurgical clipping at our hospital. Results: We focused on safely dealing with these variations during surgery, without further complications, and with good postoperative results. Patients were discharged with no significant deficit. Postoperative control, computed tomography angiography showed complete exclusion of aneurysms. Conclusion: Although anatomical variations in the parasellar region can complicate surgical clipping of these aneurysms, it is essential to ensure the best possible surgical outcome to conduct thorough preoperative and radiological evaluations.

Fluorescein videoangiography (FL-VAG) as a predictor of cerebral bypass patency.

Background: The fluorescein videoangiography (FL-VAG) has become a valuable adjunct tool in vascular neurosurgery. This work describes using the FL-VAG during bypass surgery and proposes a classification method for evaluating surgical results. Methods: We analyzed 26 patients with 50 cerebral bypasses from September 2018 to September 2022. We used a three grades classification method based on the pass of intravenous fluorescein through the anastomosis. Grade 1 represents the synchronous and total filling of the "T" shape ("green T″) formed by the donor and recipient vessel, Grade 2, the asynchronous filling of the anastomosis (incomplete/asynchronous "green T″), and Grade 3, a non-patent anastomosis (absence of "green T″). Results: Of the 26 patients, 8 underwent one bypass, 14 underwent double bypass, 2 underwent three bypasses, and 2 underwent four bypasses in two different interventions. The type of bypass was end-to-side anastomosis in 47 (94%) cases, internal maxillary artery to middle cerebral artery bypass with a radial artery graft (IMax-MCA anastomosis) in 2 (4%), and PICA-VA transposition in one (2%). We made 24 (48%) bypasses on the right side and 26 (52%) on the left side. After the initial surgery, thirty-nine (78%) bypasses were considered as Grade 1, 5 (10%) as Grade 2, and 6 (12%) as Grade 3. After intraoperative bypass patency assessment (IBPA), 45 (90%) of the bypasses were considered Grade 1 and remained patent on CTA. Conclusions: Using FL-VAG and a three-tier classification method is a reliable tool to predict bypass patency. It is safe, low-risk, and available worldwide.

Prototype of Low-Cost Microvascular Clips for Laboratory Use.

BACKGROUND: Vascular neurosurgical procedures require temporary or permanent surgical clips to treat cerebral aneurysms, arteriovenous malformations, or bypass surgery. In this scenario, surgical clips should have specific characteristics such as high-quality material, proper design, closing force, and biocompatibility. Due to these characteristics, the price of these clips does not allow their availability at the experimental surgery laboratory worldwide. METHODS: We describe here the technique for manufacturing handcrafted clips of low cost, using dental stainless steel or titanium wire of 0.18 mm, 0.20 mm, or 0.22 mm in diameter. We must complete six steps to obtain the clip using our hands and small electrician needle nose pliers for wire molding. RESULTS: These clips have a closing force of 30-60 gr/cm2 (depending on the wire diameter). They can be used in the experimental surgery laboratory to clip arteries or veins during vascular microsurgery procedures. Also, they can be used as temporary clips with confidence in low-flow bypass (v.gr. superficial temporal artery to middle cerebral artery or occipital artery to posterior inferior cerebellar artery anastomoses). CONCLUSIONS: Making practical low-cost clips for use in laboratory procedures or during low-flow anastomosis as temporary clips is possible. The main advantages are the low cost and the worldwide availability of the basic materials. The main disadvantage is the learning curve to get the ability to master the manufacturing of these clips.

Internal maxillary artery (IMax) - middle cerebral artery bypass in a patient with bilateral atherosclerotic carotid occlusion: A technical case report.

Since the first description of the possible utilization of the internal maxillary artery for bypass surgery, there are some reports of its use in aneurysm cases; however, there is no information about the possible advantages of this type of bypass for cerebral ischemic disease. We present a 77-year-old man with a history of diabetes, hypertension, systemic atherosclerosis, and two acute myocardial infarctions with left hemiparesis. Imaging studies reported total occlusion of the right internal carotid artery and 75% occlusion on the left side, with an old opercular infarction and repeated transient ischemic attacks in the right middle cerebral artery territory despite medical treatment. After a consensus, we decided to perform a bypass from the internal maxillary artery to the M2 segment of the middle cerebral artery using a radial artery graft. After performing the proximal anastomosis, the calculated graft's free flow was 216 ml/min. Subsequently, after completing the bypass, the patency was confirmed with fluorescein videoangiography and intraoperative Doppler. Postoperatively, imaging studies showed improvement in the perfusion values and the hemiparesis from 3/5 to 4+/5. The patient was discharged one week after the operation, with a modified Rankin scale of 1, without added deficits. The use of revascularization techniques in steno-occlusive disease indicates a select group of patients that may benefit from this procedure. In addition, internal maxillary artery bypass has provided a safe option for large areas of ischemia that cannot be supplied with a superficial temporal artery - middle cerebral artery bypass.

Paraclinoid aneurysms clipping through an extradural sphenoid ridge keyhole approach.

BACKGROUND: Paraclinoid aneurysms represent a challenge for neurosurgeons due to the anatomical complexity of this region. Then, innovative techniques such as the extradural sphenoid ridge approach are suitable for a safe microsurgical clipping. METHOD: A description of the surgical technique was made by the senior author, a vascular neurosurgeon experienced with the use of this approach in the management of paraclinoid aneurysms exemplified through a clinical case. CONCLUSION: Microsurgical clipping through an extradural sphenoid ridge keyhole approach for small and midsize paraclinoid aneurysms is an excellent treatment modality with good clinical and surgical results.

Limitation of fenestrated clips during clipping of middle cerebral artery aneurysm: Technical note.

Background: The middle cerebral artery (MCA) is a common site of cerebral aneurysms and 82.6% occur at the bifurcation. When surgery is selected as a therapeutic option, it intends to clip the neck completely because if some remnant occurs, there exists the possibility of regrowth and bleeding in the short- or long-term. Methods: We analyzed one drawback of the fenestrated clips of Yasargil and Sugita types to occlude the neck totally at a specific point formed by the union of the fenestra with the blades, creating a triangular space where the aneurysm can protrude, giving place to a remnant that can lead to a future recurrence and rebleeding. We show two cases of ruptured MCA aneurysms in which a cross-clipping technique occluded a broad base and dysmorphic aneurysm using straight fenestrated clips. Results: In both cases (one using a Yasargil clip and the other with a Sugita clip), a small remnant was visualized when fluorescein videoangiography (FL-VAG) was used. In both cases, the small remnant was clipped with a 3 mm straight miniclip. Conclusion: We should be aware of this drawback when clipping aneurysms using fenestrated clips to ensure a complete obliteration of the aneurysm's neck.

Lhermitte-Duclos disease: A rare case of cerebellar tumor with successful surgical treatment.

Background: Lhermitte-Duclos disease (LDD) or dysplastic gangliocytoma of the posterior fossa is a slow-growing and extremely rare mass lesion that involves the Purkinje neurons and the granular layer of the cerebellum. It is characterized by specific neuroradiological features and secondary hydrocephalus. However, documentation of surgical experience is scarce. Case Description: A 54-year-old man with LDD manifesting as progressive headache is presented with vertigo and cerebellar ataxia. Magnetic resonance imaging demonstrated a right cerebellar mass lesion with the characteristic "tiger-striped appearance." We decided to perform partial resection with reduction of tumor volume improving symptomatology as a result of the mass effect in the posterior fossa. Conclusion: Surgical resection is a good alternative for the management of LDD, especially when neurological compromise exists due to mass effect.

Microsurgical Treatment of a Giant Intracavernous Carotid Artery Aneurysm in a Pediatric Patient: Case Report and Literature Review.

Intracranial aneurysms in children account for 4%-5% of all cases, with 20% being considered giant (>25 mm). The main sites of occurrence are the internal carotid artery (ICA) and the middle cerebral artery (MCA). Rupture and secondary subarachnoid hemorrhage occur in approximately 55%-72.5% of cases, with a 10%-23% mortality rate. We report the case of a previously healthy nine-year-old girl who developed sudden, severe right retroocular pain and a holocranial headache as a mode of onset. Besides, the patient presented with double vision, and her relatives sought medical attention. Paresis of the right III, IV, and VI cranial nerves was found at physical examination. An MRI and digital subtraction angiography showed the presence of a giant aneurysm in the cavernous portion of the ICA with a mass effect. The patient was treated surgically through a high-flow bypass using a radial artery graft and trapping of the aneurysm. She had an uneventful postoperative course and was discharged three days after the operation to continue follow-up at the outpatient clinic. The therapeutic options were: a) an endovascular approach using flow diverters or stenting and coiling; or b) surgical treatment with proximal closure of the ICA if the patient had good collateral circulation or trapping the aneurysm combined with a high-flow bypass if the collateral circulation was not good or absent. After discussion, we decided on the surgical option. Even when the surgery was successful in this case, there is no consensus about the best way to treat it; the selection should be based on the center´s experience when confronting this rare entity.

Ruptured aneurysm associated with a twig-like middle cerebral artery: An illustrative case report.

Background: Anomalies of the middle cerebral artery (MCA) are rare; among the different types of anomalies, the aplastic or twig-like (Ap/T) MCA is extremely rare and has been reported under various names, including aplastic, unfused, or rete type anomaly. The occurrence of a brain aneurysm associated with this anatomic variant is an even rare event, and probably their development and rupture are related to hemodynamic stress of the tinny wall of vessels forming the network. Case Description: We present a 43-year-old male patient with an explosive and persistent right orbitofrontal headache. A computed tomography showed a right frontobasal hematoma with intraventricular disruption. Magnetic resonance angiography showed a right MCA aneurysm and what seems to be a MCA trunk stenosis. Cerebral digital subtraction angiography demonstrated a plexiform arterial network and one aneurysm arising from the network. The patient was successfully treated by surgical clipping to evacuate the hematoma and to prevent further intracranial hemorrhages. Conclusion: The Ap/T-MCA may be associated with hemodynamic stress with a significant effect through the tinny wall of the vessels causing hemorrhage or leading to the formation and rupture of cerebral aneurysms. Based on a correct diagnosis of the anomaly, treatment can be completed successfully through different standard methods.

Microsurgical treatment of carotid body tumors using periadventitial dissection: Analysis of outcomes and prognostic factors in a neurological referral center.

Background: Surgical resection for carotid body tumors (CBTs) is the gold standard of treatment and continues to be a challenging procedure, commonly associated with high vascular injury rates and neurological complications. Methods: It is a retrospective case series study between January 2002 and November 2020, with a mean follow-up of 29 months in a single nationwide referral center. Thirty-one patients diagnosed with a carotid body tumor and treated with microsurgical periadventitial resection were included in the study. Patients' demographics, comorbidities, clinical, radiological factors, and tumor grade, evaluated by the Shamblin scale, were obtained. Statistical analysis was performed on all collected data. Results: In this study, we included 31 patients (32 tumors), 80% of the patients were female, and 20% were male, with a mean age of 53 years. One patient presented with bilateral lesions, while 17 tumors were located on the left side. The most frequent symptom was a painless, slow-growing neck mass in 74% of patients. Using the Shamblin classification, 13% of tumors were Grade I, 53% Grade II, and 34% Grade III. In the postoperative period, 3% of patients presented with permanent cranial nerve deficit, while none had vascular injuries or postoperative stroke. A tumor >5 cm increased the risk for nerve lesion by 11 times (OR 12.6, CI 95% 7.4-11.4, P < 0.001). Conclusion: Preoperative embolization followed by periadventitial resection by means of a microsurgical technique is a safe and effective approach to remove CBT, with 3% cranial nerve injury rate and no need for vascular sacrifice or reconstruction.

Treatment of middle cerebral artery aneurysms: A comparative study and proposed treatment algorithm.

OBJECTIVES: We aimed to compare outcomes of patients with middle cerebral artery (MCA) aneurysms treated by either microsurgical clipping or endovascular therapy and provide a treatment algorithm based on available evidence. MATERIALS AND METHODS: We performed a retrospective analysis of 77 patients with 95 MCA aneurysms. Demographic, clinical, and aneurysm morphological variables were collected. Patients were divided into two groups depending on the received treatment. Clinical and radiological outcomes were collected at the end of a 1-year follow-up period and compared between both treatment groups. RESULTS: Mean age was 51.4 years. Fifty patients (65%) underwent microsurgical clipping and 27 (35%) were treated by endovascular therapy. Fifty-four patients (70%) presented with subarachnoid hemorrhage, while 23 (30%) were treated for unruptured aneurysms. Patients with subarachnoid hemorrhage were more frequently treated by microsurgical clipping than patients with unruptured aneurysms. Clinical outcomes, including functional status, were similar between treatment groups after 1-year follow-up even when adjusting for clinical presentation. Residual aneurysms were found less frequently in the microsurgical group (OR = 0.09; p < 0.001). CONCLUSIONS: In patients with MCA aneurysms, clinical outcomes at 1 year are similar between microsurgical clipping and endovascular therapy. However, microsurgery is associated with a lower risk of residual aneurysms.

OBJETIVO: Evaluar y comparar desenlaces de pacientes con aneurismas de arteria cerebral media (ACM) tratados mediante clipaje microquirúrgico o terapia endovascular, y proponer un algoritmo de tratamiento basado en evidencia. MATERIAL Y MÉTODOS: Estudio retrospectivo de 77 pacientes con 95 aneurismas de ACM. Se recabaron variables demográficas, clínicas y morfológicas de los aneurismas tratados. Se dividieron a los pacientes en dos grupos dependiendo del tratamiento recibido y se compararon los desenlaces clínicos y radiológicos al final del seguimiento a un año entre ambos grupos. RESULTADOS: La edad promedio fue 51.4 años. 50 pacientes (65%) fueron sometidos a clipaje microquirúrgico y 27 (35%) a terapia endovascular. 54 pacientes (70%) presentaron hemorragia subaracnoidea, quienes fueron tratados mediante microcirugía en mayor proporción que aquellos con aneurismas no rotos. Los desenlaces clínicos, incluyendo el estado funcional, fueron similares entre ambos grupos al año de seguimiento, aún tras ajustar el análisis por presentación clínica. El grupo de microcirugía presentó una menor proporción de aneurismas residuales (OR = 0.09; p < 0.001). CONCLUSIONES: En pacientes con aneurismas de ACM, los desenlaces clínicos a un año son similares entre clipaje microquirúrgico y terapia endovascular. Sin embargo, la microcirugía se asocia a un menor riesgo de aneurismas residuales.

Operative considerations and surgical treatment of sylvian fissure arteriovenous malformations: a 20-year experience.

OBJECTIVE: Sylvian fissure (SF) arteriovenous malformations (AVMs) are among the most challenging vascular lesions amenable to neurosurgical treatment and account for 10% of all locations. As radiosurgery and endovascular techniques are increasingly involved in multimodal management protocols, the role of microsurgery needs to be reassessed as a stand-alone technique. The aim of this study was to show that total excision can be achieved with reasonable levels of morbidity and mortality in a real-world setting from a specialized high-volume center. METHODS: Forty-three patients with SF AVMs were identified from a series of 577 AVM patients treated microsurgically over a 22-year period. The mean patient age was 33.07 years (range 15-60 years), and there were 22 male and 21 female patients. The mode of presentation was headache in 51.2%, hemorrhage in 34.9%, seizures in 30.2%, and steal phenomenon in 9.3%. The authors analyzed the anatomical basis and angiographic characteristics of such lesions. RESULTS: In the preoperative period, 83.7% of the patients had a modified Rankin Scale (mRS) score of 0-2, and 16.3% had an mRS score of 3-5. After a 12-month follow-up, 95.3% of patients had an mRS score of 0-2, and 4.7% had a score of 3-6. The difference between pre- and postoperative scores was not statistically significant. SF AVMs have several particular features: 1) They produce angiographic steal of the anterior cerebral artery. 2) The nidus is fed by only one of the main trunks of the middle cerebral artery (MCA). 3) Participation of deep perforators is uncommon. 4) They have two or more early draining veins showing their fistulous nature. 5) Preoperative embolization and radiosurgery have a low rate of permanent cure. CONCLUSIONS: These AVMs represent a surgical challenge due to their proximity to critical structures such as the MCA, insula, internal capsule, and speech and memory functions in the dominant hemisphere. Essential key points are the wide opening of the SF and proper differentiation between feeders and normal vessels. Although this location can seem daunting, SF AVMs carry no additional surgical risk if adequately managed.

Giant Posterior Inferior Cerebellar Artery Aneurysm Mimicking a Brainstem Tumor.

Aneurysms from the vertebrobasilar system are rare, accounting for only 5%-10% of all intracranial aneurysms. The most common sites in which these lesions occur are the bifurcation of the basilar artery and the origin of the posterior inferior cerebellar artery (PICA). When the aneurysms present in the distal portion of the PICA, they represent from 0.5% to 6%. These aneurysms are called giant when they exceed 25 mm in diameter. We present a case of a 49-year-old male who presented with acute obstructive hydrocephalus, which required ventriculoperitoneal shunting and left hemispheric cerebellar syndrome. The magnetic resonance imaging study revealed an occupative mass located in the fourth ventricle, and diagnostic angiography showed a partially thrombosed giant saccular aneurysm in the posterior inferior cerebellar artery. He underwent surgical management via a lateral suboccipital approach. The aneurysm was remodeled and clipped successfully without complications, with an uneventful postoperative course. Although rare, PICA aneurysms should always be considered when posterior fossa syndrome occurs, including brainstem and cranial nerve compression symptoms. It can easily be misdiagnosed as a neoplastic lesion, especially when the aneurysm reaches big or giant size. Therefore, complete diagnostic studies, such as cerebral angiography, must be performed. Surgical clipping must be offered as the first line of treatment. It provides occlusion of the aneurysm and relieves compressive symptoms.

Subarachnoid Hemorrhage From Rupture of an Undiagnosed Posterior Circulation Aneurysm During Sellar Tumor Surgery.

Association between cerebral aneurysms and sellar tumors has been previously reported. Rupture of anterior circulation aneurysms during a transsphenoidal surgery causing massive subarachnoid hemorrhage (SAH) is uncommon, but rupture of a posterior circulation aneurysm is an infrequent event. We present three cases of SAH secondary to rupture of an undetected posterior circulation aneurysm during transsphenoidal surgery to treat a sellar tumor. The common factor in these cases was the adverse outcome despite treatment.  The fatal outcome seen in all these cases questions whether to include a (magnetic resonance) MR angiography or (computed tomography) CT angiography during preoperative evaluation for sellar tumors in order to identify inadvertently associated aneurysms.

Neuroprotective effect of dapsone in patients with aneurysmal subarachnoid hemorrhage: a prospective, randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: In this study, the authors sought to define the differences in the incidence of delayed cerebral ischemia (DCI) between patients treated with dapsone and those treated with placebo. Secondary objectives were to define the clinical outcome at discharge and 3 months and the incidence of brain infarction. METHODS: A prospective, randomized, double-blind, placebo-controlled study was performed and included patients with aneurysmal subarachnoid hemorrhage (SAH) within 5 days from ictus who were candidates for aneurysm occlusion, and who had a Fisher grade of 3 or 4. Patients with sulfa or sulfone drug allergies, hemoglobin < 11 g/dl, known G6PD deficiency, and those refusing informed consent were excluded. A minimal relevant effect decrease of 35% in the incidence of DCI was established. Patients were randomly assigned to receive a regimen of dapsone 2.5 ml (100 mg) daily or a placebo (aluminum hydroxide suspension, 2.5 ml daily). Both groups received validated treatment for aneurysmal SAH. The appearance of DCI on CT was assessed in every patient at discharge and 3 months later. We used the chi-square test to compare the DCI incidence between both groups, and the Student t-test or nonparametric tests to compare quantitative variables. RESULTS: Overall, 48 patients (70.8% women and 29.2% men) were included. The mean age was 50 years (SD 14.28 years, range 18-72 years). Prerandomization and postrandomization characteristics were balanced, except for the necessity of intra-arterial nimodipine administration in patients treated with placebo (15.4% vs 45.5%, p = 0.029. The incidence of DCI, the primary endpoint, for the whole cohort was 43.8% and was significantly lower in the dapsone group (26.9% vs 63.6%, p = 0.011). In addition, the irreversible DCI incidence was lower in the dapsone group (11.5% vs 54.5%, p = 0.12). A favorable modified Rankin Scale score was more frequent in the dapsone group at discharge and at 3 months (76.9% vs 36.4%, p = 0.005 and 80% vs 38.9%, p = 0.019, respectively). Also, the brain infarction incidence was lower in the dapsone group (19.2% vs 63.6%, p = 0.001). There was no difference between groups regarding adverse events. CONCLUSIONS: Dapsone seems to play a role as a prophylactic agent in patients at high risk of developing DCI after aneurysmal SAH. A multicenter investigation is necessary to increase the study population and confirm the consistency of the results observed in this study.

Hypothalamic Cavernous Malformation: Surgical Technique and Literature Review.

Hypothalamic cavernous malformation (HCM) is rare, and to our knowledge, there are only 28 cases reported in the literature. An 18-year-old male presented two years ago with a severe headache followed by right eye blindness. Following imaging studies, a bleeding hypothalamic cavernoma was discovered together with another incidental cavernoma in the brain. We sustained the diagnosis of cavernomatosis, and conservative treatment was indicated. A year later, he presented severe headache and vomit; for this reason, the patient underwent a new MRI which showed a new bleeding episode of the HCM lesion. We carried out an endocrinological assessment, and microsurgical resection was recommended. Although visual impairment persisted as expected in the postoperative period, he showed good clinical recovery overall. Hypothalamic location of a cavernous malformation is infrequent, accounting for only 1% or less of these lesions, and are known to cause a variety of symptoms inducing headache, visual disturbance, and less frequently, hypothalamus dysfunction. Surgical intervention can be considered after a second symptomatic bleed, always assessing the risk of non-favorable postsurgical outcomes against the intrinsic risk that these malformations imply. Case reports like this are essential to reach a consensus towards the best treatment option for HCM.

Spontaneous regression of a thrombosed cerebral arteriovenous malformation in a patient with a prothrombotic state associated with multiple myeloma: A case report and literature review.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) are pathologic communications between veins and arteries of the brain vasculature. Its spontaneous regression is rare, and many factors have been described in the effort to explain this phenomenon, including a hypercoagulable state. CASE DESCRIPTION: We present the case of a spontaneous unruptured AVM regression in a patient where thrombosis of the malformation was found, probably due to a prothrombotic state associated with multiple myeloma (MM). CONCLUSION: We aim to contribute to the study of this rare phenomenon, presenting the relationship between a hypercoagulable state caused by MM and the spontaneous AVM regression that has not been previously reported.

Aneurisma incidental en mi consultorio / Incidental aneurysm in my office

Con regularidad, llegan a mi consulta pacientes con aneurismas que fueron hallazgos incidentales durante estudios de imagen realizados por otras causas puntuales (v.gr. cefalea recurrente, adormecimiento facial, trauma craneal o simplemente por estudios de revisión rutinarios). El hallazgo de una imagen compatible con un aneurisma inicia una serie de comentarios y recomendaciones por el médico tratante (que frecuentemente no es neurocirujano). Algunas de ellas son dirigidas con conocimiento del tema hacia opciones quirúrgicas o endovasculares, en otros casos, existe un sesgo evidente y recomendaciones que se salen de las guías de manejo hechas por las asociaciones dedicadas al tema. Un factor muy común es el hecho de que el paciente llega frecuentemente aterrorizado al consultorio por las recomen-daciones realizadas por el médico que hace el diagnóstico ("es una lesión mortal", "tiene alto riesgo de ruptura si no se trata inmediatamente", "no debe hacer ningún esfuerzo", etc.). Desafortunadamente, estas afirmaciones son en ocasiones ratificadas por neurocirujanos.

Sodium Fluorescein Videoangiography as an Adjunct to Resection of Cerebral Arteriovenous Malformations.

OBJECTIVE: To characterize dynamic changes of arteriovenous malformation using a microscope-integrated technique at the moment of performing intraoperative fluorescein videoangiography (FL-VAG) at each of the resection phases. METHODS: We prospectively recruited 12 patients with arteriovenous malformations and used FL-VAG as an ancillary technique for resection of the lesion. We analyzed transit time (TT) of FL in arterial feeders (arterial transit time [TTa]) and draining veins (venous transit time [TTv]) during the different stages of resection. To achieve this, we recorded 3 values of TT of FL (TTa, initial TTv, final TTv); when final TTv was markedly slower than initial TTv, we hypothesized that the nidus was devascularized enough and could be safely removed. RESULTS: No mortality or morbidity was related to use of FL. In most cases, TT values of arterial feeders and draining veins allowed an easier distinction between them. At advanced stages of resection, FL-VAG assessed increase in TTv (venous blood slower or absent), suggesting that most feeding arteries had been obliterated, indicating the appropriate moment for nidus removal. Optimal dose of FL was a 75-mg bolus followed by injection of 20 mL of saline solution. CONCLUSIONS: FL-VAG allows a distinction of normal from abnormal flow in draining vessels and might help the surgeon to decide when the nidus can be safely removed. This is the first study prospectively evaluating this technique, and it proposes an ideal dose for brain arteriovenous malformation surgery, in contrast to doses used in tumor cases.

Risk Factors for Unfavorable Outcomes in Surgically Treated Brainstem Cavernous Malformations.

OBJECTIVE: Brainstem cavernous malformations (BSCMs) account for up to 18% of all intracranial cavernous malformations. Due to their complex anatomic location, they represent a significant challenge for neurosurgeons. As such, the identification of risk factors associated with negative outcomes is of significant importance. We analyze a series of 50 cases of BSCMs treated surgically in order to identify risk factors for unfavorable outcomes. METHODS: Patients who underwent surgical resection of BSCM at our institution between 2000 and 2015 were retrospectively reviewed. Univariate and multivariable logistic regression models were used to identify predictors of unfavorable outcomes, defined as those with a modified Rankin score (mRs) of >2. RESULTS: Fifty Latin American patients, with a mean age of 35.85 ± 13.06 years, consisting of 29 females (58%) and 21 males (42%), underwent surgical resection. Mean modified Rankin Scale (mRs) score at admission was 2.6 ± 1.05, and the mean BCSM size was 18.00 ± 7.19 mm. The rate of gross total resection was 92%. Overall, 80% of patients showed improved or unchanged clinical status at the last follow-up period; however, only 58% of patients had a favorable outcome with a mean mRs of 2.33 ± 1.136. Multivariable logistic binary regression identified hemorrhagic recurrence (P = 0.040), lower cranial nerve deficit (P = 0.019), and BSCMs >15 mm in diameter (P = 0.006) as predictive factors for unfavorable surgical outcomes. CONCLUSION: BSCM size, compromise of lower cranial nerves, and hemorrhagic recurrence before surgery were identified as risk factors associated with unfavorable outcomes of surgically treated BSCMs in this cohort.