High-Flow Bypass with Radial Artery Graft for Cavernous Carotid Aneurysms: A Case Series

Abstract

Background: The incidence of cavernous carotid aneurysms (CCAs) of intracranial aneurysms is low. Majority of cases presented as incidental findings with benign natural progression. The most common presenting symptoms are multiple cranial neuropathies among symptomatic patients. The treatment modalities for symptomatic patients include direct surgical clipping, endovascular coil embolization, or placement of flow diverter, or indirect procedures such as occlusion of parent artery with and without revascularization techniques. The advancement in the microsurgical treatments and endovascular devices have enable a high success rate in the treatment of patients with CCAs with low morbidity and mortality rates.

Objective: To study the surgical outcomes of patients with cavernous aneurysm who underwent high-flow bypass between 2015 and 2020 in our institution.

Materials and methods: A total of six patients in a single institution presented with CCAs who were treated with high-flow bypass surgery were included in this case-series. A single-case illustration was presented focusing on the details of surgical case management of CCA. The intraoperative middle cerebral artery (MCA) pressure monitoring during bypass surgery was also described.

Results: All five female patients and one male patient who were diagnosed with cavernous carotid aneurysms were studied. The mean age was 68.8 years old (range: 24-84 years old) and the mean size of the aneurysm was 19.6mm (range: 9.7 - 30mm). There were successfully treated with high flow bypasses using radial artery graft without any neurological sequelae.

Conclusion: The surgical treatments of cavernous carotid aneurysms should be limited to experienced neurosurgeons in view of significant risk of morbidity and mortality. Endovascular procedures may be the main stay of treatments. The success shown in this case series with parent artery occlusion and bypass surgery may provide an safe alternative to the endovascular treatment.

Keywords: Cavernous carotid aneurysms; high-flow bypass surgery; outcome.

Figure 1

Preoperative three-dimensional computed tomography angiogram of the left internal carotid artery with cavernous carotid aneurysms (a: Anterior view; b: Left lateral view; c: Posterior view; d: Head view with bone window)

Figure 2

Illustration showing the positioning and skin markings (a) Minimal hair shaving with marking of the left frontotemporal scalp marking; (b) Skin marking of the neck skin incision along the skin crest and marking of the angle of the left mandible; (c) Skin marking on the left forearm of the underneath location of the radial artery localized by ultrasound Doppler

Figure 3

Superficial temporal artery-M3 anastomosis (a) Scalp incision; (b) Harvesting superficial temporal artery; (c) Harvested anterior branch of the superficial temporal artery with the main trunk; (d) Sylvian fissure dissection; (e) Preparation of donor end of the superficial temporal artery for anastomosis; (f) Left middle cerebral artery M3 arteriotomy; (g and h) superficial temporal artery-M3 end to side anastomosis; (i) Checking flow using micro-Doppler; (j) indocyanide green showing good superficial temporal artery-M3 blood flow; (k) Postsuperficial temporal artery-M3 bypass FLOW 800 analysis demonstrates yellow color indicating good artery blood flow

Figure 4

External carotid artery-radial artery graft-M2 bypass (a) harvesting left radial artery graft; (b) Exposing the distal left cavernous carotid aneurysms, proximal left external carotid artery and internal carotid artery; (c) and (d) Tunneling of the radial artery graft from cranial to neck; (e) Preparation of donor site of the radial artery graft; (f) Marking of M2 for arteriotomy; (g) Left middle cerebral artery M2 arteriotomy; (h) radial artery graft-M2 anastomosis; (i) Left external carotid arteriotomy; (j) End to side radial artery graft-external carotid artery anastomosis; (k) Checking the blood flow from radial artery graft to M2 using micro Doppler; (l) indocyanine green showing good flow from radial artery graft to the M2; (m and n) Double ligations of the proximal internal carotid artery; (o) indocyanine green showing blood flow within external carotid artery and external carotid artery - radial artery graft bypass with no flow in the internal carotid artery

Figure 5

Intraoperative imaging of indocyanine green using Flow 800 showing radial artery graft-M2 blood flow in red color indicating good flow

Figure 6

Illustrative case showing the comparison between peripheral arterial blood pressure with middle cerebral artery pressure. Without bypass. (a) Before internal carotid artery occlusion; (b) After internal carotid artery occlusion. (c) With superficial temporal artery-M3 flow but external carotid artery - radial artery graft-M2 occlusion; (d) with superficial temporal artery-M3 and external carotid artery - radial artery graft-M2 flow AND internal carotid artery occlusion

Figure 7

Postoperative magnetic resonance angiography showing arterial blood flow from external carotid artery - radial artery graft-M2 and superficial temporal artery-M3 bypasses