Universal fluorescence module for intraoperative fluorescein angiography

Acta Neurochirurgica (2019) 161:1343–1348

Even in specialized centers, suboptimal aneurysm clipping can be as high as 12%. Intraoperative fluorescence angiography with indocyanine green and, more recently, fluorescein sodium have been shown to be a good method for intraop- erative flow assessment. However, the cost with the apparatus it entails limits its widespread use.

We have developed a low-cost universal fluorescence module (FM) designed to visualize fluorescein and perform intraoperative angiography. The purpose of this paper is to describe this device as well as to present our early experience with its use in the treatment of cerebral aneurysms.

Method A FM was designed and built using a cyan-blue narrow bandpass (460 to 490 nm) excitation filter and a yellow-orange longpass (blocking wavelengths under 520 nm) barrier filter mounted on a 3D-printed holding tray in a specific disposition to perfectly match the light source and the objective lens of the surgical microscope. It allowed switching from white light to fluorescence mode in a simple and sterile fashion. Its perfect attachment to the microscope was possible by reusing the lens fittings extracted from used original drape sets that would otherwise be discarded. Four patients underwent aneurysm clipping using the FM at two institutions from April to September 2018.

Results A bright green fluorescence against a dark background was observed after intravenous bolus of fluorescein. Blood vessels became obviously distinct from non-contrast-filled structures such as clipped aneurysms and the brain. Vascular anatomy could be appreciated without any distortion, including perforating arteries.

Conclusions Intraoperative fluorescence angiography was successfully performed with the use of this universal FM after intra- venous injection of fluorescein sodium. This simple and low-cost device may be useful in resource-limited centers, where other sorts of intraoperative angiography are not available.

Impact of Indocyanine Green Videoangiography on Rate of Clip Adjustments Following Intraoperative Angiography

Essentials in intraoperative indocyanine green videoangiography assessment for intracranial aneurysm surgery

Neurosurgery 75:437–444, 2014

Intraoperative angiography (IA) is used to evaluate the adequacy of clip reconstruction of intracranial aneurysms. Alternative imaging such as indocyanine green videoangiography (ICG-VA) has been proposed. The additional benefit of ICG-VA when IA is routinely used has not been previously determined.

OBJECTIVE: To report our experience with the use of ICG-VA in combination with IA vs IA alone.

METHODS: We retrospectively reviewed cases of aneurysm clipping during a 21-month period by a single surgeon in which ICG-VA was performed after clip reconstruction prior to IA, or IA alone was performed to verify optimal clipping. Records were reviewed for age, sex, race, length of stay, rupture status, Hunt and Hess grade, aneurysm size, location, and temporary clipping. Intraoperative decision making was determined for each group.

RESULTS: Ninety-four patients who underwent 97 craniotomies for 128 aneurysms met inclusion criteria for this study. ICG-VA1IA was performed in 37 craniotomies; IA alone was performed for 60 craniotomies. Baseline characteristics were similar with the exception that median aneurysm size was slightly larger in the ICG-VA group (5.6 mm vs 4.3 mm, P = .04). ICG-VA produced 4 false negatives, which required clip adjustments following IA (10.8%), vs 7 patients (11.7%) in the IA-alone group requiring clip adjustments (P = .897).

CONCLUSION: When IA is routinely performed, the additional use of ICG-VA does not eliminate the need for post-IA clip adjustments owing to the possibility of false negatives. When ICG-VA suggests optimal clipping, but is followed by IA, the rate of post-IA modifications in this study did not differ significantly than if ICG-VA had not been performed.

Intraoperative angiography reloaded: a new hybrid operating theater for combined endovascular and surgical treatment of cerebral arteriovenous malformations

Intraoperative angiography reloaded

Acta Neurochir (2013) 155:2071–2078

Multimodality treatment suites for patients with cerebral arteriovenous malformations (AVM) have recently become available. This study was designed to evaluate feasibility, safety and impact on treatment of a new intraoperative flat-panel (FP) based integrated surgical and imaging suite for combined endovascular and surgical treatment of cerebral AVM.

Methods Twenty-five patients with AVMs to treat with combined endovascular and surgical interventions were prospectively enrolled in this consecutive case series. The hybrid suite allows combined endovascular and surgical approaches with intraoperative scanner-like imaging (XperCT®) and intraoperative 3D rotational angiography (3D-RA). The impact of intraoperative multimodal imaging on feasibility, workflow of combined interventions, surgery, and unexpected imaging findings were analyzed.

Results Twenty-five patients (mean age 38±18.6 year) with a median Spetzler-Martin grade 2 AVM (range 1–4) underwent combined endovascular and surgical procedures. Sixteen patients presented with a ruptured AVM and nine with an unruptured AVM. In 16 % (n=4) of cases, intraoperative imaging visualized AVM remnants ≤3 mm and allowed for completion of the resections in the same sessions. Complete resection was confirmed in all n =16 patients who had follow-up angiography one year after surgery so far. All diagnostic and therapeutical steps, including angiographic control, were performed without having to move the patients

Conclusion The hybrid neurointerventional suite was shown to be a safe and useful setup which allowed for unconstrained combined microsurgical and neuroradiological workflow. It reduces the need for extraoperative angiographic controls and subsequent potential surgical revisions a second time, as small AVM remnants can be detected with high security.

Safety and Efficacy of Intraoperative Angiography in Craniotomies for Cerebral Aneurysms and Arteriovenous Malformations

Intraoperative angiography in aneurysms surgery

Neurosurgery 71:1162–1169, 2012

In an era of indocyanine angiography, the routine use of intraoperative angiography (IOA) in the surgical treatment of aneurysms and vascular malformations is controversial.

OBJECTIVE: To retrospectively assess the safety and efficacy of IOA and to determine predictors of surgical revision.

METHODS: Between 2003 and 2011, IOA was performed during surgical treatment of 976 aneurysms, 101 arteriovenous malformations (AVMs), and 16 arteriovenous fistulas.

RESULTS: In 80 of 976 aneurysms (8.2%), IOA prompted clip repositioning. The reason for readjustment was residual aneurysm in 54.7%, parent vessel occlusion in 42.9%, and both in 2.4% of cases. In multivariate analysis, increasing aneurysm size (P,.001), ruptured aneurysm (P,.001), and increasing number of vessels injected (P,.001) were strong predictors of clip readjustment. There was a strong trend for posterior circulation aneurysm location to predict clip repositioning (P = .06). IOA revealed residual nidus/ fistula requiring further intervention in 9 of 101 AVMs (8.9%) and 3 of 16 arteriovenous fistulas (18.8%). Of 9 AVMs requiring a surgical revision, 2 (22.2%) were Spetzler-Martin grade II, 5 (55.6%) were grade III, and 2 (22.2%) were grade IV. Mean Spetzler-Martin grade was 3.0 in AVMs requiring surgical revision compared with 2.3 in those not requiring revision (P = .05). IOA-related complications were all transient or minor and occurred in 0.99% of patients; none resulted in permanent morbidity.

CONCLUSION: IOA remains a valuable tool in the surgical treatment of brain vascular abnormalities, guiding surgical re-exploration in >8% of cases. Easy access to an angiographer and routine use of IOA are important factors contributing to procedural safety and efficacy.

Use of Microscope-Integrated Near-Infrared Indocyanine Green Videoangiography in the Surgical Treatment of Spinal Dural Arteriovenous Fistulae

Neurosurgery 66:978-985, 2010 DOI: 10.1227/01.NEU.0000368108.94233.22

Identification and complete interruption of fistulae are essential but not always obvious during the surgical treatment of spinal dural arteriovenous fistulae (dAVFs). We examined cases in which we identified and confirmed surgical obliteration of a spinal dAVF with the aid of microscope-integrated near-infrared indocyanine green (ICG) videoangiography.

METHODS: ICG videoangiography was performed during 6 surgical interventions in which 6 intradural dorsal AVFs (type I) were interrupted. An operating microscope-integrated light source containing infrared excitation light illuminated the operating field and was used to visualize an intravenous bolus of ICG. The locations of fistulae, feeding arteries, and draining veins and documentation of occlusion of the fistulae were compared with findings on preoperative and postoperative digital subtraction angiography.

RESULTS: ICG videoangiography identified the fistulous point(s), feeding arteries, and draining veins in all 6 cases, as confirmed by immediate postoperative selective spinal angiography. In 1 case, intraoperative ICG ruled out an additional questionable fistula at a contiguous level suspected on the preoperative angiography.

CONCLUSION:Microscope-based ICG videoangiography is simple and provides real-time information about the precise location of spinal dAVFs. During spinal dAVF surgery, this technique can be useful as an independent form of angiography or as an adjunct to intraor postoperative digital subtraction angiography. Larger series are needed to determine whether use of this modality could reduce the need for immediate postoperative spinal angiography after obliteration of intradural dorsal AVFs.