Intermediate-grade brain arteriovenous malformations and the boundary of operability using the supplemented Spetzler-Martin grading system

J Neurosurg 136:125–133, 2022

Supplemented Spetzler-Martin grading (Supp-SM), which is the combination of Spetzler-Martin and Lawton-Young grades, was validated as being more accurate than stand-alone Spetzler-Martin grading, but an operability cutoff was not established. In this study, the authors surgically treated intermediate-grade AVMs to provide prognostic factors for neurological outcomes and to define AVMs at the boundary of operability.

METHODS Surgically treated Supp-SM intermediate-grade (5, 6, and 7) AVMs were analyzed from 2011 to 2018 at two medical centers. Worsened neurological outcomes were defined as increased modified Rankin Scale (mRS) scores on postoperative examinations. A second analysis of 2000–2011 data for Supp-SM grade 6 and 7 AVMs was performed to determine the subtypes with improved or unchanged outcomes. Patients were separated into three groups based on nidus size (S1: < 3 cm, S2: 3–6 cm, S3: > 6 cm) and age (A1: < 20 years, A2: 20–40 years, A3: > 40 years), followed by any combination of the combined supplemented grade: low risk (S1A1, S1A2, S2A1), intermediate risk (S2A2, S1A3, S3A1, or high risk (S3A3, S3A2, S2A3).

RESULTS Two hundred forty-six patients had intermediate Supp-SM grade AVMs. Of these patients, 102 had Supp-SM grade 5 (41.5%), 99 had Supp-SM grade 6 (40.2%), and 45 had Supp-SM grade 7 (18.3%). Significant differences in the proportions of patients with worse mRS scores at follow-up were found between the groups, with 24.5% (25/102) of patients in Supp-SM grade 5, 29.3% (29/99) in Supp-SM grade 6, and 57.8% (26/45) in Supp-SM grade 7 (p < 0.001). Patients with Supp-SM grade 7 AVMs had significantly increased odds of worse postoperative mRS scores (p < 0.001; OR 3.7, 95% CI 1.9–7.3). In the expanded cohort of 349 Supp-SM grade 6 AVM patients, a significantly higher proportion of older patients with larger Supp-SM grade 6 AVMs (grade 6+, 38.6%) had neurological deterioration than the others with Supp-SM grade 6 AVMs (22.9%, p = 0.02). Conversely, in an expanded cohort of 197 Supp-SM grade 7 AVM patients, a significantly lower proportion of younger patients with smaller Supp-SM grade 7 AVMs (grade 7–, 19%) had neurological deterioration than the others with Supp-SM grade 7 AVMs (44.9%, p = 0.01).

CONCLUSIONS Patients with Supp-SM grade 7 AVMs are at increased risk of worse postoperative neurological outcomes, making Supp-SM grade 6 an appropriate operability cutoff. However, young patients with small niduses in the low-risk Supp-SM grade 7 group (grade 7−) have favorable postoperative outcomes. Outcomes in Supp-SM grade 7 patients did not improve with surgeon experience, indicating that the operability boundary is a hard limit reflecting the complexity of high-grade AVMs.

Evaluation of Serial Intraoperative Surgical Microscope-Integrated Intraoperative Near-Infrared Indocyanine Green Videoangiography in Patients With Cerebral Arteriovenous Malformations

Neurosurgery 70[ONS Suppl 1]:ons34–ons43, 2012 DOI: 10.1227/NEU.0b013e31822d9749 

With the use of indocyanine green (ICG) as a novel fluorescent dye, fluorescence angiography has recently reemerged as a viable option.

OBJECTIVE: To show the result of ICG videoangiography in cases of cerebral arteriovenous malformations.

METHODS: Twenty-seven ICG videoangiography procedures were performed in 11 patients with cerebral arteriovenous malformations. Intraoperative digital subtraction angiography (DSA) was performed 27 times in these patients. The timing of intraoperative DSA was before dissection, after clipping of feeders, and after dissection of the nidus.

RESULTS: The procedures were performed in 4.7 ± 1.4 minutes (mean ± SD; n = 27 minutes), whereas intraoperative digital subtraction angiography was performed for a mean of 16.6 ± 3.8 minutes (n = 27 minutes). In predissection studies, feeders were visualized by ICG in 3 of 9 cases. The nidus was visualized in all 9 cases, and drainers were visualized in 8. Intraoperative DSA visualized the feeders, nidus, and drainers in all 9 cases. After clipping of feeders, ICG videoangiography showed flow reduction of the nidus in 7 of 7 cases. Intraoperative DSA also showed that finding in 9 of 9 cases. After total dissection of the nidus, all cases disclosed that the drainers were without ICG filling. Intraoperative DSA also showed that result in all of the cases. Unexpected residual nidus was not visualized in our series with either method.

CONCLUSION: We found that ICG videoangiography is helpful for resecting cerebral arteriovenous malformation. It is especially effective in visualizing the nidus and superficial drainers, as well as changes in flow after clipping or coagulating of feeders.

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