PMC8769404_01
(A) Sagittal MRI demonstrates an enhanced solid tumor with a cyst in the dorsal medulla oblongata. (B) Postoperative sagittal MRI reveals total resection of the tumor. Lateral-view right (C) and left (D) vertebral angiograms reveal the tumor is mainly fed by the PICA and radiculomeningeal artery from the C2 segmental artery. (E) Picture of the hybrid operating room. MRI: magnetic resonance imaging, PICA: posterior inferior cerebellar artery.
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Magnetic resonance imaging (MRI) revealed an enhancing solid tumor with a maximum diameter of 3.0 cm accompanying a cyst in the dorsal medulla oblongata (Fig. 1A). Digital subtraction angiography (DSA) demonstrated a highly vascularized tumor mainly fed by bilateral posterior inferior cerebellar arteries (PICAs) and radiculomeningeal arteries from bilateral C2 segmental arteries (Figs. 1C and 1D). ICG videoangiography is routinely performed in the hybrid operating room (Fig. 1E) for AVM surgery in our institution to assess the flow dynamics of niduses using an ICG videoangiography technology-integrated microscope (Kinevo 900; Carl Zeiss, Oberkochen, Germany). Intra-arterial ICG videoangiography was approved by the ethics review board at Postoperative MRI revealed total resection of the tumor (Fig. 1B).
Surgical views before (A) and after partial coagulation of superficial feeders (E) and after partial (I, M) and total (O) dissection of the tumor. Upper is the caudal side, lower is the rostral side. ICG videoangiography studies (B-D, F-H, J-L, and N, P) were performed at the time of the operation. On intraoperative ICG videoangiography, feeders appear at 1 s, then feeders disappear and drainers appear at 5 s, then drainers disappear at 10 s. Normal veins are still present at 10 s (B-D). After coagulating the superficial feeders of the caudal and right sides (E), ICG videoangiography reveals that superficial feeders of the left side are present at 1 s, whereas some drainers are still present at 10 s, indicating reduced flow in the tumor (F-H). After dissection of the superficial part of the tumor (I), ICG videoangiography demonstrates no appearance of superficial feeders at 1 s, whereas drainers are still present at 5 and 10 s, indicating that the tumor is supplied by remaining deep feeders (J-L). The deep part of the tumor is carefully dissected by coagulating deep feeders (M). ICG videoangiography shows that the main drainer is still filled with ICG (N), indicating that the tumor is not completely dissected. The tumor is removed after ICG videoangiography shows no filling of ICG in the main drainer (P). ICG: indocyanine green.
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After opening the dura mater, multiple tumor-related vessels were exposed in the cisterna magna (Fig. 2A). Normal veins were still present at 10 s (Figs. 2B-2D). After coagulating the superficial feeders of the caudal and right sides (Fig. 2E), ICG videoangiography disclosed superficial feeders on the left side at 1 s, whereas some drainers were still present at 10 s, indicating reduced flow in the tumor (Figs. 2F-2H). After dissection of the superficial part of the tumor (Fig. 2I), ICG videoangiography demonstrated no appearance of superficial feeders at 1 s, whereas drainers were still present at 5 and 10 s, indicating that the tumor was supplied by the remaining deep feeders (Figs. 2J-2L). The deep part of the tumor was carefully dissected by coagulating the deep feeders (Fig. 2M). ICG videoangiography subsequently showed that the main drainer was still filled with ICG (Fig. 2N), indicating that the tumor had not been completely dissected. The tumor was removed after ICG videoangiography showed no filling of ICG in the main drainer (Fig. 2O and 2P).
The captured video is analyzed by Flow 800. Surgical views before (A) and after (C) partial coagulation of superficial feeders. Upper is the caudal side, lower is the rostral side. The color of the drainer before coagulation of superficial feeders (B) is yellow, changing to blue after coagulation (D), demonstrating that Flow 800 can detect even small decelerations in blood flow. The diagram also shows that ROI-1 (squares in E and F) slowly increases (F) compared to that observed in the precoagulation diagram (E). Delay time is prolonged in ROI-1 and speed is slowed after coagulation of superficial feeders (F) as compared to that observed before coagulation (E). ROI: region of interest.
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Prior to dissection (Fig. 3A), the color of the drainer was yellow (Fig. 3B), changing to blue after partial coagulation of the superficial feeders on the caudal and right sides (Figs. 3C and 3D). As seen in a diagram for region of interest (ROI)-1 (Figs. 3E and 3F), a slower increase was seen compared to that on the pre-dissection diagram. In addition, compared to the pre-dissection diagram (Fig. 3E), the delay time in ROI-1 was prolonged, and blood flow slowed after partial coagulation of the superficial feeders (Fig. 3F).