Resection Of Arteriovenous Malformations Research Articles

Chronic traumatic encephalopathy pathognomonic lesions occurring in isolation adjacent to infiltrative and non-infiltrative white matter lesions.

Chronic traumatic encephalopathy (CTE) is defined by perivascular neuronal phosphorylated-tau accumulation at cortical sulcal depths. CTE has been mainly described in the context of repetitive, impact-type traumatic brain injury (rTBI), principally from contact sports. Rarely, CTE has been associated with single TBIs, including in relationship to healed leucotomy sites in brains from formerly institutionalized psychiatric patients without documented rTBI. Given that leucotomy principally involves severing of white matter, this could suggest involvement of axonal injury in CTE pathophysiology. We present three cases wherein isolated CTE pathology was identified adjacent to distinct white matter lesions. Case 1 is a 41-year-old man with history of hereditary hemorrhagic telangiectasia and resection of a cerebral arteriovenous malformation (AVM). Case 2 is a 46-year-old man with glioblastoma. Case 3 is a 52-year-old man with a remote cerebral infarct. Isolated CTE lesions were found adjacent to the aforementioned pathologies in each case. Additional CTE lesions were not identified despite extensive sampling. Multiple age-related tau astrogliopathy (ARTAG)-like lesions were also identified at other sulcal depths near the AVM resection site in Case 1. These cases may provide insights regarding the pathophysiology of the CTE pathognomonic lesion and the development of ARTAG-like pathology adjacent to long-standing mass lesions.

Posterior Interhemispheric-Transtentorial Approach for Resection of an Arteriovenous Malformation of the Superior Medullary Velum and Fourth Ventricle: 2-Dimensional Operative Video.

Brain arteriovenous malformations (AVMs) of the fourth ventricle represent a rare subtype associated with an aggressive natural course.1,2 In this case, a woman in her early 50s presented with dizziness. An AVM was diagnosed in the left superior cerebellar peduncle extending into the fourth ventricle. The AVM was supplied by superior cerebellar artery branches and classified as a Spetzler-Martin grade III and a Lawton-Young grade III, with a supplemented grade of 6.3,4 Being a single case report, institutional review board approval was not needed. Patient consent was obtained. The lesion was accessed through a torcular craniotomy and posterior interhemispheric-transtentorial approach, employing gravity to naturally retract the parietooccipital lobe.5-7 Dissection continued into the quadrigeminal and ambient cisterns, where the tentorium was incised parallelling the straight sinus to reach the superior vermis. Partial resection of the lingual and central lobules of the vermis facilitated access to the superior medullary velum. The superior cerebellar artery feeders were divided and followed to the superior cerebellar peduncle and through the superior medullary vellum. A vertical incision in the superior medullary velum facilitated entry into the fourth ventricle, where the AVM nidus was dissected circumferentially and resected en bloc. Intraoperative indocyanine green videoangiography and postoperative digital subtraction angiography confirmed complete obliteration of the AVM. After surgery, the patient experienced mild ataxia, but motor symptoms greatly improved during 3-month follow-up. This video illustrates resection of a complex fourth ventricular AVM through a posterior interhemispheric-transtentorial approach, highlighting pivotal considerations of patient positioning and approach selection to optimize treatment outcome for complex posterior fossa AVM resection.

Microsurgical Resection of a Lateral Pontine Arteriovenous Malformation Masquerading as a Cavernous Malformation: 2-Dimensional Operative Video.

Although cavernous malformations (CMs) often demonstrate characteristic T2 heterogeneity and gadolinium enhancement, whereas arteriovenous malformations (AVMs) appear as tangles of T2 hypointense flow voids, small lesions in deep locations may have equivocal features on preoperative imaging.1-4 This video presents an unusual case of a lateral pontine AVM masquerading as a CM. The patient presented with sudden-onset headache, dizziness, double vision, and left facial numbness. Diagnostic imaging findings suggested a hemorrhagic left lateral pontine mass lesion, most consistent with brainstem CM. Resection through a left extended retrosigmoid craniotomy was recommended. Patient consent was obtained. During dissection, a prominent petrosal vein tributary was noted to be arterialized, which was concerning for AVM. Indocyanine green videoangiography (ICG-VA) was performed to confirm the diagnosis, and the intraoperative plan was dynamically adjusted in accordance with the principles of AVM resection. The small superficial feeding arteries were identified and disconnected, and the nidus was dissected circumferentially with the pial resection technique. After dearterialization, the draining petrosal vein was noted to darken, and repeat ICG-VA confirmed complete occlusion of the AVM without residual shunting. The patient recovered well, with no neurological deficits, and postoperative angiography confirmed complete resection of the Spetzler-Martin grade III AVM. Key learning points for this unusual case include the importance of dynamic interpretation of intraoperative findings, openness to alterations of the surgical plan when integrating new diagnostic information, and the integration of ICG-VA as a critical tool for differentiating CMs and AVMs during microsurgical resection. Images in Surgical Video © 2024 Barrow Neurological Institute. Used with permission.

Mixed reality in neurosurgery: redefining the paradigm for arteriovenous malformation planning and navigation to improve patient outcomes.

Brain arteriovenous malformations (AVMs) present significant challenges in neurosurgery, requiring detailed planning and execution. In this study, the authors aimed to evaluate the efficacy of mixed reality (MxR), a synergistic application of virtual reality (VR) and augmented reality (AR), in the surgical management of AVMs. A retrospective review was conducted on 10 patients who underwent AVM resection between 2021 and 2023. Preoperative planning used patient-specific 360° VR models, while intraoperative guidance used AR markers for targeted disconnection of arterial feeders. Data were analyzed for surgical duration, blood loss, and postoperative outcomes, stratified by Spetzler-Martin (SM) and supplemented Spetzler-Martin (Supp-SM) grades. In 10 patients with cerebral AVMs, MxR significantly facilitated the identification of 21 arterial feeders, including challenging deep feeders. MxR-assisted surgeries demonstrated efficient identification and disconnection of arterial feeders, contributing to precise AVM resection. The mean surgical duration was approximately 5 hours 11 minutes, with a mean intraoperative blood loss of 507.5 ml. Statistically significant variations in surgical duration and blood loss were observed based on SM and supplemented Supp-SM grades. Two patients experienced worsened postoperative neurological deficits, underscoring the inherent risks of AVM surgeries. The marked difference in hospital stays between patients with ruptured and those with unruptured AVMs, particularly for SM grade III, highlights the significant impact of rupture status on postoperative recovery. In this study, the authors delineated a novel paradigm using MxR for the surgical intervention of AVMs. Using 3D VR for preoperative planning and AR for intraoperative guidance, they achieved unparalleled precision and efficiency in targeting deep arterial feeders. While the results are promising, larger studies are needed to further validate this approach.

Updates on Neuronavigation: Emerging tools for tumor resection.

Multiple studies have been conducted to properly elucidate the various tools available to help enhance the resection of tumor tissue, aneurysms, and arteriovenous malformations (AVM). Diffusion tensor imaging (DTI) tractography is useful in providing a map of the tumor borders, allowing the optimal preservation of function and structure of specific regions of the brain. During neurosurgery, especially craniotomies, the possibility of the brain shifting due to swelling or gravity is high. Thus, tools for intraoperative imaging such as high-frequency linear array ultrasound transducers and doppler ultrasonography are utilized for high resolution images and detecting frequency shifts. 4D-digital subtraction angiography (DSA) is another technique used to create spatial resolutions and 3D maps for aneurysms. These similar techniques can also be utilized to assess the integrity of white matter in AVM. By implementing effective evaluation strategies, healthcare professionals can make informed decisions regarding treatment options, preventive measures, and long-term care plans tailored to individual patients.

Anatomical Variations and Anomalies of the Middle Cerebral Artery

Intracranial arteries have a high rate of variation, but a clear schematic overview is lacking. In this pictorial review we classify and depict all the variations and anomalies within the middle cerebral artery (MCA). PubMed was searched with the MeSH-term "Middle Cerebral Artery." Articles were selected based on their description of variants within the MCA. Cross-referencing was used to broaden the range of articles. The anatomical variants were then schematically drawn using the anteroposterior and lateral view during angiography of the internal carotid artery. A total of 29 unique medical illustrations were made, depicting variation in number of vessels; variation in vessel origin; and variation in morphology. The MCA provides vital blood supply to the frontal, parietal, temporal, and central brain structures. An overview of these variations is important to diagnose and treat patients with MCA-related pathology correctly and safely. They can aid in distinguishing pathology from normal anatomical variance; aid neurosurgeons during aneurysmal clipping or arteriovenous malformation resections; and aid interventional radiologists during thrombectomy or coiling. This article provides a summary regarding current knowledge of anatomical variations within the MCA, their prevalence and clinical relevance. A total of 29 unique illustrations were made, depicting currently known variants. We encourage all who diagnose, treat, and study the MCA to use this overview for a uniform and better understanding of its anatomy.

Dual Microscope Indocyanine Green Video Angiography and Endoscopic Review to Treat Intracranial Aneurysm: A Review of the Literature Regarding a Case.

The use of the indocyanine green video angiography (ICG-VA) both endoscope and microscope has become popular in recent decades thanks to the safety, efficacy, and added value that they have provided for cerebrovascular surgery. The dual use of these technologies is considered complementary and has helped cerebrovascular surgeons in decision-making, especially for aneurysm clipping surgery; however, its use has been described for both aneurysm surgery, resection of arteriovenous malformations, or even for bypass surgeries. We conducted a review of the literature with the MeSH terms "microscope indocyanine green video angiography (mICG-VA)," "endoscopic review," AND/OR "intracranial aneurysm." A total of 97 articles that included these terms were selected after a primary review to select a total of 26 articles for the final review. We also present a case to exemplify its use, in which we use both technological tools for the description of the aneurysm, as well as for decision-making at the time of clipping and for reclipping. Both tools, both the use of the endoscope and the mICG-VA, have helped decision-making in neurovascular surgery. A considerable clip replacement rate has been described with the use of these technologies, which has helped to reduce the complications associated with poor clipping. One of the main advantages of their usefulness is that they are tools for intraoperative use, which is why they have shown superiority compared to digital subtraction angiography, which takes longer to use and has a higher risk of complications associated with the contrast medium. On the other hand, a very low rate of complications has been described with the use of the endoscope and mICG-VA, which is why they are considered safe tools to use. In some cases, mention has been made of the use of one or the other technology; however, we consider that its dual use provides more information about the status of the clip, its anatomy, its relationship with other vascular structures, and the complete occlusion of the aneurysm. We consider that the use of both technologies is complementary, so in case of having them both should be used, since both the endoscope and the mICG-VA provide additional and useful information.

Use of near infrared spectroscopy for the prediction of perioperative complications in patients undergoing elective microsurgical resection of cerebral arteriovenous malformations- a prospective observational trial (NIRSCAM trial).

Cerebral arteriovenous malformations (AVM) represent focal abnormal areas of low resistance circulation which render the peri-nidal neuronal tissue susceptible to ischemia. The post-excision cerebral perfusion surge can result in hyperaemic complications.We hypothesised that Near Infrared Spectroscopy (NIRS)-guided perioperative management can aid in the prediction and prevention of perioperative complications in patients presenting for surgical excision of cerebral AVMs. We also intended to identify a threshold value of regional cerebral oxygen saturation (rScO2) to predict the incidence of perioperative complications. This was a prospective observational study involving patients undergoing elective supratentorial AVM resection surgeries. Intraoperative rScO2 and hemodynamic monitoring were done and continued for postoperatively for 12h. Any drift in rScO2 by > 12% from baseline was managed as per study protocol and perioperative adverse events were recorded and analyzed. Post surgery,for analytical purpose patients were categorized into two groups, Group A - patients without complications and Group B - patients who had complications postoperatively. Twenty-five patients presenting for surgical excision of cerebral AVM were recruited for this study of which 9 patients had postoperative adverse events and were allocated to group B. The ipsilateral mean rScO2 at the time of complication (Pc) was significantly lower in Group B than in group A [62.08 ± 9.33 vs.70.52 ± 7.17; p = 0.04]. The mean ipsilateral rScO2 drift from N2- N5 (i.e., post excision) was significantly higher in Group B than in Group A [12.01 ± 2.63% vs. 4.98 ± 5.7%;p = 0.02]. Mean ipsilateral rScO2 Drift ratio (N5 :N2) was significantly higher in group B as compared to group A [1.32 ± 0.01 vs. 1.01 ± 0.06;p < 0.001]. In the immediate post excision phase, the ipsilateral mean rScO2 was significantly higher in Group B at the post excision time point compared to Group A [ 83.03 ± 6.08 vs. 73.52 ± 7.07;p < 0.01)]. The mean ipsilateral rScO2 drift from N1-N6 (i.e., postoperatively) was significantly higher in Group B as compared to Group A [14.96 ± 0.080% vs. 6.88 ± 4.5% ; p < 0.01]. Similarly, the Mean Ipsilateral rScO2 Drift ratio (N6:N1) was significantly lower in group B as compared to group A [2.17 ± 0.02 vs. 1.05 ± 0.03 ;p < 0.0001]. In patients undergoing cerebral AVM resection, a post-resection ipsilateral rScO2 increase by > 12% with a drift ratio of > 1.3 could signify cerebral hyperemia. A postoperative ipsilateral rScO2 drift > 14.5% with a drift ratio of 2.1 from the baseline is associated with postoperative complications in our study. Further multi-centric randomized control trials are needed to support our research findings.

Microsurgical resection of a ruptured intraventricular arteriovenous malformation in a neonate: considerations in management. Illustrative case.

Arteriovenous malformations (AVMs) are the most common cause of intracranial hemorrhage in children, although they are rarer in neonates. Age, location, lesion architecture, and rupture status define treatment options. Sparse literature exists to guide the management of clinically symptomatic intraventricular AVM rupture in neonates. We highlight the case of a neonate with a ruptured intraventricular AVM to showcase considerations in treatment, discuss surgical technique, and help guide management. An 18-day-old female presented with lethargy in extremis and was found to have new intraventricular hemorrhage. Angiogram revealed a Spetzler-Martin grade 2 AVM with a right posterior choroidal feeder and deep venous drainage within the ventricle. Her age limited radiosurgical and endovascular interventions. She underwent an interhemispheric, transcollosal, intraventricular approach for complete AVM resection. Perioperative care was managed by a multidisciplinary team, successfully mitigating the patient's high risk of hemovascular collapse. Stereotactic radiosurgery, endovascular embolization, and microsurgery are options for AVM obliteration, and multimodal therapy must be tailored to the lesion and patient. Conservative management can also be considered. Each intervention carries risks and varying likelihoods of success. Balancing these outcomes is challenging without definitive, high-quality, evidence-based guidance. The best treatment maximizes the chance of AVM obliteration while minimizing morbidity.

Ischemic stroke in a young adult with a known epileptogenic arteriovenous malformation: illustrative case.

Brain arteriovenous malformations (AVMs) usually manifest as hemorrhages or seizures. They rarely present with ischemic symptoms, especially in young patients. We present a case of an epileptogenic AVM that led to cerebral infarction due to paradoxical embolic occlusion of the middle cerebral artery (MCA) involving the main feeder of the lesion. A 35-year-old male had been suffering from AVM-associated epilepsy for 10 years and was scheduled for surgery. He suddenly developed right-sided hemiconvulsions followed by hemiparalysis and impaired consciousness. Computed tomography revealed no intracerebral hemorrhage, and symptoms were initially thought to indicate epilepsy and Todd's palsy. Because of his prolonged symptoms, he underwent magnetic resonance imaging, which revealed a large cerebral infarction due to occlusion of the MCA involving the main feeder of the AVM. The patient underwent AVM resection, and the partially thrombosed nidus was completely removed. Histopathological investigation revealed a fresh thrombus in totally occluded nonarteriosclerotic feeders. He had no atrial fibrillation; however, subsequent transesophageal echocardiography revealed a patent foramen ovale, suggesting a paradoxical embolism. This case serves as a reminder that AVMs can present with considerable variability. Acute cerebral infarction should be considered a possible mechanism of seizures, even in patients with epileptogenic AVM.

Postoperative de novo epilepsy after resection of brain arteriovenous malformations: a national database study of 536 patients.

We aimed to assess the incidence and risk factors for de novo epilepsy after AVM resection and compare them with a non-resection cohort after propensity score matching, utilizing a national database. Utilizing the TriNetX Research Network, we queried cases from 1/1/2004 to 3/1/2022. We included patients of all ages who underwent supratentorial AVM resection, presenting without seizures on or before surgery and without being on antiseizure medications at least 1 day before surgery. The primary outcome was seizures manifesting at least 6 weeks after surgery. Patient characteristics and outcomes were compared between the cohorts with and without postoperative epilepsy. Further cohorts were created to compare cohorts with and without embolization or rupture. After propensity score matching, we compared an additional cohort of patients with an AVM diagnosis who did not undergo resection. Of the 536 patients (mean age 38.9±19.6, 52% females) presenting without seizure who underwent AVM resection, 99 (18.5%) developed de novo epilepsy, with a one-year cumulative incidence of 13.8%. Patients with epilepsy had higher rates of intracerebral hemorrhage, and intracerebral hemorrhage was less common in the embolization cohort. Patients in the ruptured cohort were older and more often males. After propensity score matching with 18588 patients with AVM diagnosis but no resection, each group consisted of 529 patients, and de novo epilepsy at 1 year was significantly higher in the AVM resection cohort compared to the non-resection cohort (11.5% vs. 3.4%, p<0.001). This analysis of 536 patients provides evidence that de novo epilepsy after brain AVM resection occurs at a one-year cumulative incidence of 13.8%, with a total of 19.4% developing de novo epilepsy. Intracerebral hemorrhage was inconsistently associated with postoperative de novo epilepsy. De novo epilepsy was significantly less frequent after AVM diagnosis without resection.

Microsurgical Treatment of Arteriovenous Malformations: A Single-Center Study Experience.

The purpose of the study was to assess the functional outcomes after microsurgical resection of arteriovenous malformations (AVMs) and to compare the results between patients eligible for A Randomized Trial of Unruptured Brain Arteriovenous Malformations in this surgical series to the results reported and the ARUBA study. We reviewed the records of 169 patients who underwent microsurgical treatment of arteriovenous malformation (AVMs) in our institution between January 2016 and December 2021. These patients' functional status was assessed using modified Rankin Scale (mRS) scores at the last follow-up and before treatment. The mRS scores at the latest follow-up were classified into good outcomes (mRS < 3) and poor outcomes (mRS ≥ 3). Clinical presentation, patients' demographics, AVM characteristics, follow-up time, and obliteration rate were analyzed. Subgroup analyses were performed on the whole cohort, comparing Spetzler-Martin Grade I and Grade II, and ARUBA-eligible AVMs. The initial hemorrhagic presentation occurred in 71 (42%) out of 169 patients. The majority of the patients presented with headaches (73%). The AVMs were completely obliterated in 166 (98.2%) patients. The series included 65 Spetzler-Martin Grade I (38.5%), 46 Grade II (27.2%), 32 Grade III (18.9%), 22 Grade IV (13%), and 4 Grade V (2.4%) AVMs. There were 98 unruptured and 79 ARUBA-eligible cases. Also, optimal functional outcome was achieved in 145 (85.8%) patients. The overall mortality rate was 5.3% (9/169). The multivariate analysis illustrated that a poor outcome was significantly associated with presurgical mRS ≥3 (p < 0.013; OR, 0.206; 95% CI 0.059-0.713), increasing age (p < 0.045; odds ratio [OR], 1.022; 95% CI 1.000-0.045), and female gender (p < 0.009; OR, 2.991; 95% CI 1.309-6.832). Our study suggests that better outcomes can be obtained using microsurgical resection in the majority of patients with AVMs. Independent predictors of poor outcomes after surgical resection of AVMs include increasing age at the time of surgery, poor presurgical functional status, and female gender. Supposing that patients are more suitable for microsurgery after presurgical examination, outcomes are normally better in that case than those achieved by multimodal interventions (such as conservative treatment or ARUBA treatment arm). Therefore, we recommend early surgical removal on all surgically accessible AVMs to prevent successive hemorrhages and the consequences of poor neurological outcomes.

Descending the reconstructive ladder: Salvage reconstruction by tissue expansion to revise a free flap-based forehead reconstruction

Abstract Background: Forehead defects pose a reconstructive challenge and multiple revisions are often required to achieve satisfactory outcomes. Materials and Methods: The case history of a 20-year-old woman undergoing radical resection of a forehead arteriovenous malformation and reconstruction with an anterolateral (ALT) free flap is described. Results: Although free tissue transfer with an ALT was successful, its color and texture mismatch were unacceptable to the patient. The esthetic result and patient satisfaction were improved by subsequent tissue expansion of the contralateral forehead, removal of the free flap and advancement of the contralateral forehead skin. Conclusion: Complex reconstructions utilize a breadth of techniques. We illustrate a dynamic use of the reconstructive ladder, implementing a descending approach to achieve a satisfactory reconstruction objectively and subjectively from the patient perspective.

Outcomes of Microsurgical Resection of Low-Grade Cerebral Arteriovenous Malformations: A Prospective Observational Multicenter Study from a Low-Middle-Income Country

ObjectiveTo appraise the overall outcomes of microsurgical resection of low-grade arteriovenous malformations (AVMs) in a low-middle-income country. MethodsData was collected prospectively from three different neurosurgical centres in Pakistan for this study and it lasted for two years. According to the Spetzler-Martin (S-M) grading system, patients diagnosed with cerebral AVMs were divided into three classes A, B, and C. AVMs of grade 1 and 2 were included in Class A. Class B contained grade 3 AVMs, while Class C contained grade 4 and 5 AVMs. All male and female patients in Class A were eligible for this study. Patients were evaluated postoperatively for seizures, haemorrhage, focal neurological deficits, and AVM cure rates. Morbidity, mortality, and functional recovery were used to evaluate the outcome. Functional recovery and cure rate were observed after 6 months of follow-up. ResultsThere were a total of 22 patients. Mean age was 36.41 ± 14.32 SD years. There were 12 (54.5 %) male patients and 10 (45.5 %) female patients. 13 patients (59.1 %) presented with spontaneous intracerebral haemorrhage, while 9 patients (40.9 %) presented with seizures. 14 patients (63.6 %) had S-M grade 1 and 8 patients (36.4 %) had S-M grade 2. All patients underwent microsurgical resection. We discovered 4.5 % morbidity in our study. There was no postoperative mortality. At 6 months, an excellent functional outcome of 95.5 % (according to the Glasgow outcome scale) and 100 % cure rate was observed. ConclusionMicrosurgery is a safe and effective treatment for low-grade AVMs in terms of morbidity, mortality, functional outcome and cure rates in our country.

Commentary: Resection of Arteriovenous Malformation With Sonolucent Cranioplasty: 2-Dimensional Operative Video With 360° Virtual Reality Fly-Through.

Department of Neurosurgery, Faculty of Medicine, Cairo University, Cairo, Egypt Correspondence: Nasser M. F. El-Ghandour, MD, Department of Neurosurgery, Faculty of Medicine, Cairo University, 81 Nasr Rd, Nasr City, Cairo11371, Egypt. Email: [email protected]

How I do it? Surgical removal of a corpus callosum arteriovenous malformation using a robotic digital microscope.

This report described the surgical nuance of a challenging deep-seated corpus callosum arteriovenous malformation (AVM) using a novel robotic digital microscope. A 64-year-old male was admitted to treat a ruptured corpus callosum AVM. In order to facilitate surgical manipulation under the robotic digital microscope, a gravity-assisted supine position was utilized. Intraoperatively, identifying and preserving the transit and bystander artery is important while skeletonizing the anterior cerebral artery. The nidus was totally resected and the patient was discharged without sequella. It is feasible to perform complicated AVM resection under the robotic digital microscope with a rigorous surgical plan.

Intraosseous resection of mandibular arteriovenous malformations: A mandible sparing multi-disciplinary case series

Mandibular arteriovenous malformations (AVMs) are high flow vascular malformations that can cause pain, hypertrophy, deformity, malocclusion, jaw asymmetry, bone destruction, tooth loss, and severe bleeding [1]. Although general principles apply, the rarity of mandibular AVMs limits definitive agreement on the best course of treatment. Current treatment options include embolization, sclerotherapy, surgical resection, or some combination of techniques [2]. [3]. An alternative multidisciplinary technique of embolization with mandibular-sparing resection is presented. This technique aims to mitigate bleeding with effective removal of the AVM, while preserving mandibular form, function, dentition, and occlusion.

A Classification Proposal for Spinal Vascular Lesions.

A Classification Proposal for Spinal Vascular Lesions.

Microsurgical resection of a ruptured right peri-ventricular brain arteriovenous malformation with preoperative embolization.

A 41-year-old female presented with a headache and left inferior quadrantanopia. Imaging demonstrated a clot spanning the atrium of the ventricle to the superior parietal lobule (SPL), with a small arteriovenous malformation (AVM) nidus outside the atrium of the ventricle. The nidus was supplied by parieto-occipital arterial (P4) feeders with a single atrial draining vein. Pre-operative embolization of a pedicle with Onyx provided a surgical marker. A parietal craniotomy was performed with a trans-cortical SPL approach. During AVM resection, the draining vein was injured, which was stabilized using a temporary clip to "spot weld" the defect and continue nidus dissection with patent venous outflow. After careful dissection, coagulation, and division of all the arterial feeders, the AVM was mobilized and the draining vein was clipped, coagulated, and divided. Follow-up indocyanine green angiography and cerebral angiography both confirmed complete resection of the AVM. The patient consented to the procedure and to publication.

You Take the Low Road: Differential Outcomes After Tangential and Transcortical Approaches to Medial Temporal Brain Arteriovenous Malformations

Microsurgical resection of medial temporal brain arteriovenous malformations (AVMs) is typically conducted through 2 approaches: the orbitozygomatic-tangential and subtemporal-transcortical. Relative indications and outcomes for these techniques have not been formally compared. The cerebrovascular database of a quaternary center was reviewed for patients with medial temporal AVMs treated between January 1, 1997, and July 31, 2021. Demographic characteristics, lesion characteristics, surgical approaches, and outcomes were retrospectively analyzed and compared. Postoperative outcome testing was performed using the Montreal Cognitive Assessment and Global Quality of Life Scale. Fifty-nine patients were assessed. Mean (standard deviation) age was 31 (18) years; 30 (51%) patients were male. Of the AVMs, 29 (49%) were left-sided and 30 (51%) were right-sided. The tangential approach was selected in 20 (34%) cases, whereas the transcortical technique was preferred in 39 (66%). Improved modified Rankin Scale status was significantly associated with the tangential resection technique both in the early postoperative period (P= 0.02) and at last follow-up (P= 0.01). Differences between the tangential and transcortical approaches were not significant with respect to new postoperative deficits (5/20 [25%] vs. 12/39 [31%], P= 0.87) or the presence of residual AVM on follow-up angiography (1/20 [6%] vs. 5/39 [14%], P= 0.65). The orbitozygomatic-tangential strategy was associated with favorable functional and quality-of-life outcomes after medial temporal AVM resection. These benefits are likely to be attributable to minimization of temporal retraction, avoidance of brain transgression, and avoidance of traction on the vein of Labbé, rendering the orbitozygomatic-tangential approach the preferred option for cases that are anatomically amenable to either strategy.