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

Early versus Delayed Surgical Management of Ruptured Arteriovenous Brain Malformations in a Tertiary Referral Center in Colombia, South America

BACKGROUND

Surgical timing after rupture of brain arteriovenous malformations (AVMs) is controversial. There is scarce literature on AVM surgical outcomes from developing countries. This study aims to determine if there is a difference between early and delayed surgical resection for patients with ruptured brain AVMs.

METHODS

This single-center retrospective review included patients who underwent surgical resection for ruptured brain AVMs in Colombia. Patients were stratified by the timing of surgical intervention relative to the rupture into early (≤72 hours of bleeding) and delayed (>72 hours) resection. Continuous variables were analyzed using an independent t-test, and dichotomous variables were analyzed using a χ2 test. A linear regression analysis was performed with the final mRankin score at 2 years as the dependent variable; P < 0.05 was considered significant.

RESULTS

Thirty-one patients were identified. The early treatment group included 14 (45.2%) patients, and the delayed group included 17 (54.8%) patients. The mean (SD) length of time between AVM rupture and surgical resection was 1.6 ± 1.2 days and 12.4 ± 8.4 days, respectively (P < 0.001). There were no differences regarding demographics, perioperative variables, and postoperative outcomes between groups. In the linear regression analysis, the only variable that had a significant association with the final mRankin score was the initial Glasgow Coma Scale, which had a β coefficient of -0.6341 (95% confidence interval: -0.41,-0.017, P = 0.035).

CONCLUSIONS

In this case series of 31 patients from a developing country, there were no differences in clinical outcomes at the final follow-up between acute and delayed surgical interventions for ruptured AVMs. The most important factor associated with the final outcomes was the initial Glasgow Coma Scale.

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.

Fluorescein-Guided Surgery for Arteriovenous Malformation

Microscopes with fluorescence modality for videoangiography (VAG) using indocyanine green or sodium fluorescein (FL) have been used in cerebrovascular surgeries as tools for brain blood flow assessment in vascular diseases, especially in brain aneurysms, extracranial-intracranial bypass, and arteriovenous malformations (AVMs). Indocyanine green-VAG is a well-documented tool frequently employed as an adjunct to microsurgery for AVM treatment. Nevertheless, it's worth noting that the use of FL-VAG has been significantly underrepresented in medical literature, with only a few studies addressing its application in this context.1,2 We report a case of a 33-year-old woman with a grade 1 frontal unruptured AVM, admitted because of recurrent headache. The AVM was exposed with a centered craniotomy (Video 1). Three FL injections were administered at different timing: 1) at the procedure's outset (before any dissection), 2) when the surgeon estimated most feeders had been disconnected, and 3) after the removal of the nidus. FL-VAG allowed visualization of the superficial AVM vessels and its draining veins. After identification and disconnection of feeding arteries, diminished blood flow was visualized and the AVM was completely removed, confirming no residual lesion by absence of FL on the surgical bed. Postoperative digital angiography showed complete removal of the AVM. FL-VAG represents a valuable adjunct in the AVM resection by facilitating the assessment of blood flow within cerebral vessels. This can be helpful to modify surgical strategies in some circumstances (e.g., selection of the main feeders vs. arteries in passage) and to save time making decisions about draining vein division and nidus removal.

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.

Application of Fluorescein Fluorescence in Vascular Neurosurgery

Background: Fluorescein sodium (FNa) is a fluorescent drug with a long history of use for assessing retinal blood flow in ophthalmology; however, its application in vascular neurosurgery is only now gaining popularity. This review summarizes the current knowledge about using FNa videoangiography in vascular neurosurgery.

Methods: We performed a literature review on the usage of FNa for fluorescent videoangiography procedures in neurosurgery. We analyzed methods of injection, dosages of FNa, visualizing platforms, and interpretation of FNa videoangiography. We also reviewed practical applications of FNa videoangiography during various vascular neurosurgeries.

Results: FNa videoangiography can be performed with intraarterial (intracarotid) or intravenous dye injections. Both methods provide excellent resolution with enhanced fluorescence that shows intravascular blood flow on top of visible surrounding anatomy, and both allow simultaneous purposeful microsurgical manipulations. Although it is invasive, an intracarotid FNa injection results in faster contrast appearance and higher-intensity fluorescence and requires a lower dose per injection (reported range, 1–50 mg) compared with peripheral intravenous FNa injection (reported range, 75–2,000 mg or 1–1.5 mg/kg body weight). Four optical excitation/detection tools for FNa videoangiography have been successfully used: conventional xenon-light operating microscope with a special filter set, pencil-type light-emitting diode probe with a filter set, laser-illumination operating microscope, and an endoscope with a filter set. FNa videoangiography was reported to be feasible and useful in various clinical scenarios, such as examining the feeders and drainers in arteriovenous malformation surgery, checking the patency of a microvascular anastomosis, and assessing blood flow during aneurysm clipping. FNa videoangiography can be repeated during the same procedure and used along with indocyanine green (ICG) videoangiography.

Conclusions: Compared with ICG videoangiography, FNa videoangiography has the advantages of enabling real-time inspection and better visualization at deep locations; however, thick vessel walls limit visualization of FNa in larger vessels. FNa videoangiography is a useful tool in multiple neurovascular scenarios and merits further studies to establish its clinical value.