Spetzler-Martin grade IV and V arteriovenous malformations: Treatment outcomes and risk factors for negative outcomes after surgical resection

Enhancing the quality of evidence, comparability, and reproducibility in brain arteriovenous malformations treated with open surgery research: a systematic review and proposal of a reporting guideline for surgical and clinical outcomes

Brain Arteriovenous Malformations (bAVMs) are rare but high-risk developmental anomalies of the vascular system. Microsurgery through craniotomy is believed to be the mainstay standard treatment for many grades of bAVMs. However, a significant challenge emerges in the existing body of clinical studies on open surgery for bAVMs: the lack of reproducibility and comparability. This study aims to assess the quality of studies reporting clinical and surgical outcomes for bAVMs treated by open surgery and develop a reporting guideline checklist focusing on essential elements to ensure comparability and reproducibility. This is a systematic literature review that followed the PRISMA guidelines with the search in Medline, Embase, and Web of Science databases, for studies published between January 1, 2018, and December 1, 2023. Included studies were scrutinized focusing on seven domains: (1) Assessment of How Studies Reported on the Baseline Characteristics of the Patient Sample; (2) Assessment and reporting on bAVMs grading, anatomical characteristics, and radiological aspects; (3) Angioarchitecture Assessment and Reporting; (4) Reporting on Pivotal Concepts Definitions; (5) Reporting on Neurosurgeon(s) and Staff Characteristics; (6) Reporting on Surgical Details; (7) Assessing and Reporting Clinical and Surgical Outcomes and AEs. A total of 47 studies comprising 5,884 patients were included. The scrutiny of the studies identified that the current literature in bAVM open surgery is deficient in many aspects, ranging from fundamental pieces of information of methodology to baseline characteristics of included patients and data reporting. Included studies demonstrated a lack of reproducibility that hinders building cumulative evidence. A bAVM Open Surgery Reporting Guideline with 65 items distributed across eight domains was developed and is proposed in this study aiming to address these shortcomings. This systematic review identified that the available literature regarding microsurgery for bAVM treatment, particularly in studies reporting clinical and surgical outcomes, lacks rigorous scientific methodology and quality in reporting. The proposed bAVM Open Surgery Reporting Guideline covers all essential aspects and is a potential solution to address these shortcomings and increase transparency, comparability, and reproducibility in this scenario. This proposal aims to advance the level of evidence and enhance knowledge regarding the Open Surgery treatment for bAVMs.

Unruptured brain arteriovenous malformations causing seizures localize to one common brain network

Seizures are a frequent symptom of unruptured brain arteriovenous malformations (bAVMs). However, the brain regions responsible for these seizures remain unclear. To identify the brain regions causally involved in bAVM-related seizures, we retrospectively reviewed 220 patients with unruptured bAVMs. Using voxel-based lesion-symptom mapping (VLSM) analyses, we tested whether individual brain regions were associated with unruptured bAVM-related seizures. The result revealed that unruptured bAVMs causing seizures are anatomically heterogeneous at the voxel level. Subsequently, lesion network mapping (LNM) analyses was performed to determine whether bAVMs causing seizures belonged to a distributed brain network. LNM analyses indicated that these lesions were located in a functional network characterized by connectivity to the left caudate and precuneus. Moreover, the discrimination performance of the identified seizure network was evaluated in discovery set by calculating the individualized network damage score and was tested in validation set. Based on the calculated network damage scores, patients were divided into low-, medium-, and high-risk groups. The prevalence of seizures significantly differed among the three risk categories in both discovery (p = .003) and validation set (p = .004). Finally, we calculated the percentage of voxels in the canonical resting-state networks that overlapped with the seizure-susceptible brain regions to investigate the involvement of resting-state networks. With an involvement percentage over 50%, the frontoparietal control (82.9%), limbic function (76.7%), and default mode network (69.3%) were considered to be impacted in bAVM-related seizures. Our study identified the seizure-susceptible brain regions for unruptured bAVMs, which could be a plausible neuroimaging biomarker in predicting possible seizures.

Single-Stage Combined Embolization and Resection for Spetzler-Martin Grade III/IV/V Arteriovenous Malformations: A Single-Center Experience and Literature Review

Background and Purpose: This study sought to identify the efficacy and intraoperative operational details of single-stage combined embolization and microsurgery strategy for Spetzler-Martin (SM) grade III/IV/V arteriovenous malformations (AVMs).

Methods: The authors retrospectively reviewed consecutive SM grade III/IV/V AVMs who underwent hybrid procedures and surgical resection alone procedures from January 2016 to February 2018. Outcomes [modified Rankin Scale (mRS)] were compared between hybrid group and surgical resection alone group in ruptured or unruptured subgroup. Factors associated with long-term disability were assessed using multivariable logistic regression analyses.

Results: A total of 100 AVM patients (47 corrected using hybrid procedures whereas 53 by surgical resection alone) were evaluated. After a mean follow-up of 2.3 ± 0.6 years, we found no difference in long-term prognosis and incidences of disability rates between these two strategies. However, the hybrid strategy offers significant advantage in accelerating the resection process [ruptured (P = 0.000); unruptured (P = 0.002)]. In the analysis of risk factors, excessive embolization (Grade C, 60–100%) was significantly associated with long-term disability in the hybrid cohorts (P = 0.041; odds ratio, 24.000; 95% CI, 1.140–505.194), and involvement of deep perforating arteries was the significant predictor of long-term disability in the surgical resection alone cohort (P = 0.025; odds ratio, 15.389; 95% CI, 1.412–167.66). In the subgroup analysis of the hybrid cohort, moderate embolization (Grade B, 30–60%) was recommended because of the low risk ratio of major intraoperative bleeding (P = 0.033).

Conclusions: Single-stage combined embolization and resection is an efficient strategy for the treatment of SM grade III/IV/V AVMs. Although the long-term outcomes were similar to surgical resection alone, the hybrid strategy had obvious advantages of shorter resection. In the hybrid technique, moderate embolization was recommended, and excessive embolization might be detrimental to the subsequent microsurgical resection.

Clinical Trial Registration:http://www.clinicaltrials.gov. Unique identifier: NCT04136860.