Internal Maxillary Artery Bypass Research Articles

Internal maxillary artery (IMax) - middle cerebral artery bypass in a patient with bilateral atherosclerotic carotid occlusion: A technical case report.

Since the first description of the possible utilization of the internal maxillary artery for bypass surgery, there are some reports of its use in aneurysm cases; however, there is no information about the possible advantages of this type of bypass for cerebral ischemic disease. We present a 77-year-old man with a history of diabetes, hypertension, systemic atherosclerosis, and two acute myocardial infarctions with left hemiparesis. Imaging studies reported total occlusion of the right internal carotid artery and 75% occlusion on the left side, with an old opercular infarction and repeated transient ischemic attacks in the right middle cerebral artery territory despite medical treatment. After a consensus, we decided to perform a bypass from the internal maxillary artery to the M2 segment of the middle cerebral artery using a radial artery graft. After performing the proximal anastomosis, the calculated graft's free flow was 216 ml/min. Subsequently, after completing the bypass, the patency was confirmed with fluorescein videoangiography and intraoperative Doppler. Postoperatively, imaging studies showed improvement in the perfusion values and the hemiparesis from 3/5 to 4+/5. The patient was discharged one week after the operation, with a modified Rankin scale of 1, without added deficits. The use of revascularization techniques in steno-occlusive disease indicates a select group of patients that may benefit from this procedure. In addition, internal maxillary artery bypass has provided a safe option for large areas of ischemia that cannot be supplied with a superficial temporal artery - middle cerebral artery bypass.

How I do it: internal maxillary artery to middle cerebral artery bypass to manage giant thrombosed internal carotid artery aneurysm.

Internal maxillary artery (IMA) bypass has become popularized due to its medium-to-high blood flow, short graft length, and well-matched arterial caliber between donor and recipient vessels. We described an open surgery of a NEW "workhorse," the IMA bypass, to treat a giant, thrombosed cerebral aneurysm. The extracranial middle infratemporal fossa (EMITF) approach was used to unveil the pterygoid segment of the IMA for cerebral revascularization. Although this technique is technically challenging, the variations in IMA can be effectively identified and sufficiently exposed in this technique to achieve favorable clinical outcomes with a high bypass patency rate.

Letter to the Editor: “Can I Afford to Become a Neurosurgeon in the United Kingdom in the Current Atmosphere?”

Cerebral revascularization strategies through extracranial to intracranial bypass have been adopted in the management of complex intracranial aneurysms. The internal maxillary artery used as a donor in a bypass is an effective method. At present, there are few quantitative analyses of cerebral blood flow perfusion. The main focus of this study was to evaluate the effectiveness of blood perfusion after bypass grafting.From April 2015 to December 2017, 19 patients who underwent internal maxillary artery radial artery middle cerebral artery bypass surgery with unobstructed bypass vessels were selected. Cerebral blood flow perfusion before and after bypass surgery was quantitatively evaluated by computed tomography perfusion imaging. The cerebral blood perfusion in the region of interest was measured by computed tomography perfusion.The aneurysms were excised after trapping in 2 cases with mass effects and neural compression. Proximal occlusion of the parent artery was performed in 9 cases of fusiform or giant dissecting aneurysms. Trapping was performed after bypass surgery in 8 cases. Within 3 months after surgery, 17 patients had good outcomes. After the hypothesis test, there was a significant difference between the preoperative △cerebral blood volume and postoperative △cerebral blood volume in the anterior area of the semioval center cross section (P = 0.001 < 0.05).The internal maxillary artery as a bypass donor is an effective method that can provide sufficient intracranial blood perfusion, and there is usually no cerebral ischemia in the surrounding area.

Letter to the Editor Regarding “Burnout Among Neurosurgeons and Residents in Neurosurgery: A Systematic Review and Meta-Analysis of the Literature”

Cerebral revascularization strategies through extracranial to intracranial bypass have been adopted in the management of complex intracranial aneurysms. The internal maxillary artery used as a donor in a bypass is an effective method. At present, there are few quantitative analyses of cerebral blood flow perfusion. The main focus of this study was to evaluate the effectiveness of blood perfusion after bypass grafting.From April 2015 to December 2017, 19 patients who underwent internal maxillary artery radial artery middle cerebral artery bypass surgery with unobstructed bypass vessels were selected. Cerebral blood flow perfusion before and after bypass surgery was quantitatively evaluated by computed tomography perfusion imaging. The cerebral blood perfusion in the region of interest was measured by computed tomography perfusion.The aneurysms were excised after trapping in 2 cases with mass effects and neural compression. Proximal occlusion of the parent artery was performed in 9 cases of fusiform or giant dissecting aneurysms. Trapping was performed after bypass surgery in 8 cases. Within 3 months after surgery, 17 patients had good outcomes. After the hypothesis test, there was a significant difference between the preoperative △cerebral blood volume and postoperative △cerebral blood volume in the anterior area of the semioval center cross section (P = 0.001 < 0.05).The internal maxillary artery as a bypass donor is an effective method that can provide sufficient intracranial blood perfusion, and there is usually no cerebral ischemia in the surrounding area.

Computed Tomography Perfusion Imaging Study of Intracranial Complex Aneurysms Treated by Internal Maxillary Artery Bypass Grafting

Cerebral revascularization strategies through extracranial to intracranial bypass have been adopted in the management of complex intracranial aneurysms. The internal maxillary artery used as a donor in a bypass is an effective method. At present, there are few quantitative analyses of cerebral blood flow perfusion. The main focus of this study was to evaluate the effectiveness of blood perfusion after bypass grafting. From April 2015 to December 2017, 19 patients who underwent internal maxillary artery radial artery middle cerebral artery bypass surgery with unobstructed bypass vessels were selected. Cerebral blood flow perfusion before and after bypass surgery was quantitatively evaluated by computed tomography perfusion imaging. The cerebral blood perfusion in the region of interest was measured by computed tomography perfusion. The aneurysms were excised after trapping in 2 cases with mass effects and neural compression. Proximal occlusion of the parent artery was performed in 9 cases of fusiform or giant dissecting aneurysms. Trapping was performed after bypass surgery in 8 cases. Within 3months after surgery, 17 patients had good outcomes. After the hypothesis test, there was a significant difference between the preoperative △cerebral blood volume and postoperative △cerebral blood volume in the anterior area of the semioval center cross section (P=0.001<0.05). The internal maxillary artery as a bypass donor is an effective method that can provide sufficient intracranial blood perfusion, and there is usually no cerebral ischemia in the surrounding area.

Maximal Resection of Tumors Encasing the Internal Carotid Artery and Hindering Internal Carotid Artery Expansion Followed by Revascularization Surgery: A Series of Nine Cases at a Single Tertiary Center.

PurposeCerebral reconstruction appears to play a diminished role in managing complex skull base tumors involving vital neurovascular structures.Materials and MethodsPatients with recurrent or progressive middle cranial fossa tumors treated by radical resection followed by extracranial-to-intracranial (EC-IC) bypass from 2014 to 2019 were included. Balloon test occlusion (BTO) was performed preoperatively.ResultsOverall, 9 patients (5 males, 4 females; mean age, 29.9 years) were enrolled. The lesions arose from the parasellar region (3), cavernous sinus (3), petroclival region (2), or orbital apex (1), and all encased the cavernous/petrous portion of the internal carotid artery. Before tumor resection, internal maxillary artery (IMA) bypass was performed for 7 patients, cervical EC-IC bypass was performed for 1 patient, and interposed superficial temporal artery (STA) bypass was performed for 1 patient. BTO failed in 8 patients and was tolerated by one patient. Intraoperative blood flow of the interposed graft was 79.7 ± 37.86 ml/min after IMA bypass, 190.6 ml/min following cervical EC-IC bypass and 75 ml/min after interposed STA bypass. All bypasses were patent on intraoperative indocyanine green angiography. Radical tumor resection was achieved in 5 patients (55.6%), and patency was confirmed postoperatively in 88.8% (8/9) of bypasses. Six patients showed favorable outcomes at discharge. At the 2-year follow-up, 7 patients (77.8%) had favorable outcomes (Karnofsky Performance Scale score>80). At the 1.5-year follow-up, one patient had died due to infarction; at the 3-year follow-up, another patient had developed tumor recurrence despite being asymptomatic.ConclusionCerebral bypass remains a vital tool for managing select middle cranial fossa tumors that invade or erode the surrounding neurovasculature or hinder carotid artery expansion and are difficult to resect.

Internal maxillary artery bypass for the treatment of complex middle cerebral artery aneurysms

OBJECTIVEThe rapid innovation of the endovascular armamentarium results in a decreased number of indications for a classic surgical approach. However, a middle cerebral artery (MCA) aneurysm remains the best example of one for which results have favored microsurgery over endovascular intervention. In this study, the authors aimed to evaluate the experience and efficacy regarding surgical outcomes after applying internal maxillary artery (IMA) bypass for complex MCA aneurysms (CMCAAs).METHODSAll IMA bypasses performed between January 2010 and July 2018 in a single-center, single-surgeon practice were screened.RESULTSIn total, 12 patients (9 males, 3 females) with CMCAAs managed by high-flow IMA bypass were identified. The mean size of CMCAAs was 23.7 mm (range 10-37 mm), and the patients had a mean age of 31.7 years (range 14-56 years). The aneurysms were proximally occluded in 8 cases, completely trapped in 3 cases, and completely resected in 1 case. The radial artery was used as the graft vessel in all cases. At discharge, the graft patency rate was 83.3% (n = 10), and all aneurysms were completely eliminated (83.3%, n = 10) or greatly diminished (16.7%, n = 2) from the circulation. Postoperative ischemia was detected in 2 patients as a result of graft occlusion, and 1 patient presenting with subarachnoid hemorrhage achieved improved modified Rankin Scale scores compared to the preoperative status but retained some neurological deficits. Therefore, neurological assessment at discharge showed that 9 of the 12 patients experienced unremarkable outcomes. The mean interval time from bypass to angiographic and clinical follow-up was 28.7 months (range 2-74 months) and 53.1 months (range 19-82 months), respectively. Although 2 grafts remained occluded, all aneurysms were isolated from the circulation, and no patient had an unfavorable outcome.CONCLUSIONSThe satisfactory result in the present study demonstrated that IMA bypass is a promising method for the treatment of CMCAAs and should be maintained in the neurosurgical armamentarium. However, cases with intraoperative radical resection or inappropriate bypass recipient selection such as aneurysmal wall should be meticulously chosen with respect to the subtype of MCA aneurysm.

The History and Evolution of Internal Maxillary Artery Bypass.

Internal maxillary artery (IMA) bypass has gained momentum in the last 5 years for the treatment of complex cerebrovascular disorders and skull base tumors. However, some issues regarding this treatment modality have been proposed. As one of the most experienced neurosurgical teams to perform internal maxillary artery bypass in the world (>100 clinical cases), we reviewed the literature in aspects of basic anatomy of maxillary artery with its variations to the lateral pterygoid muscle, initial anastomosis modalities, and subsequent exposure techniques in cadaver studies, preoperative arterial evaluation methods, optimal interposed graft selections, and surgical outcome in the management of complex aneurysms, skull base tumors, and steno-occlusive disorders.

Internal Maxillary Bypass for Complex Pediatric Aneurysms

Complex pediatric aneurysms (PAs) are an unusual clinicopathologic entity. Data regarding the use of a bypass procedure to treat complex PAs are limited. Internal maxillary artery-to-middle cerebral artery bypass with radial artery graft was used to isolate PAs. Bypass patency and aneurysm stability were evaluated using intraoperative Doppler ultrasound, indocyanine green videoangiography, and postoperative angiography. Modified Rankin Scale was used to assess neurologic function. Over a 5-year period, 7 pediatric patients (≤18 years old) were included in our analysis. Mean age of patients was 14.4 years (range, 12-18 years), and mean size of PAs was 23.6 mm (range, 9-37 mm). All cases manifested with complex characteristics. Proximal artery occlusion was performed in 3 cases, complete excision following aneurysmal distal internal maxillary artery bypass was performed in 2 cases, and combined proximal artery occlusion and aneurysm excision was performed in the 2 remaining cases. Mean intraoperative blood flowwas 61.6 mL/minute (range, 40.0-90.8 mL/minute). Graft patency rate was 100% during postoperative recovery and at the last follow-up examination (mean, 20 months; range, 7-45 months). All patients had excellent outcomes except for 1 patient who died of multiple-organ failure. Internal maxillary artery bypass is an essential technique for treatment of selected cases of complex PAs.

Flow reversal bypass surgery: a treatment option for giant serpentine and dolichoectatic aneurysms-internal maxillary artery bypass with an interposed radial artery graft followed by parent artery occlusion.

Giant serpentine and dolichoectatic aneurysms (GSDAs) are a small subgroup of intracranial aneurysms that often have poor clinical outcomes and are hardly to be treated by either conservative or endovascular management. We assessed seven patients who underwent internal maxillary artery bypass using radial artery graft interposition followed by parent artery occlusion to treat GSDAs. Intraoperative Doppler ultrasonography was used to assess the patency of the graft. CT angiogram or DSA were used postoperatively. The patients received follow-up after discharge and their neurological outcomes were measured using the Glasgow Outcome Score. Postoperative angiogram demonstrated that all the grafted conduits were patent, and the aneurysms were absent in two and collapsed or shrank in five of the patients. The rate of normal life or independent daily activities after internal maxillary artery bypass in the anterior and posterior GSDA patients was 66.7 and 75%, respectively. One patient experienced postoperative frontal ischemia and was managed conservatively. His symptoms had completely resolved at discharge. No patient encountered perforator's occlusion in the series. During 2.6years follow-up, six patients experienced favorable outcomes. One patient died in the third year after discharge attribute to unrelated disease. Based on the mechanism of flow reversal, internal maxillary artery bypass with radial artery graft followed by patent artery occlusion is an effective, minimally invasive treatment modality for select patients with GSDAs.

Internal maxillary artery to intracranial artery bypass: a case series of 31 patients with chronic internal carotid/middle cerebral arterial-sclerotic steno-occlusive disease

Objective: To evaluate the effectiveness of internal maxillary artery (IMA) – radial artery graft (RAG) – middle cerebral artery (MCA) bypass surgery for chronic arterial-sclerotic severe stenosis or occlusion of the internal carotid artery (ICA) or MCA.Methods: A retrospective study was conducted in 31 patients with ischemic cerebrovascular disease who underwent bypass surgery of the IMA with a RAG of the MCA. Twenty-seven patients had complete occlusion of the ICA or MCA, and four patients had severe stenosis of the M1 segment of the MCA.Results: Patent IMA-RAG-MCA in 30 (96.8%) patients was confirmed by angiography after surgery. One case developed a new motor aphasia due to unsuccessful bypass. Eleven transient ischemic attacks (TIA) and five ischemic strokes resolved following surgery. The other 14 cases showed some improvement without ischemic events at one month following surgery. Prior to surgery, mean ± SD National Institute of Health Stroke Scale (NIHSS) score was 5.4 ± 1.1 in the ischemic stroke group. In the first month post-procedure, the NIHSS score decreased significantly to 3.8 ± 1.2, (p < 0.01). Perfusion weighted imaging (PWI) or computed tomography perfusion (CTP) indicated improved hemodynamics in 30 patients. In addition, seven patients demonstrated improved glucose metabolism on 18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) postoperatively. No new neurological deficit occurred in the 30 patients during a 2.19 ± 1.59 years of follow-up.Conclusions: By supplying an adequate flow to a larger flow territory of chronically stenotic/occlusive major cerebral arteries, IMA bypass surgery is efficient for restoring hemodynamics in selected patients and improving their neurological deficits.

Pipeline Embolization Device: Lessons Learned After 1000 Aneurysms

Giant intracranial aneurysms (GIAs) can be approached via microsurgical and endovascular techniques. Use of flow diversion devices has yielded favorable outcomes, and indications for cerebral revascularization have dramatically decreased.To evaluate the safety and validity of using internal maxillary artery (IMA) bypass with an interposed graft to treat GIAs.During a 6-year period, high-flow IMA bypass procedures were performed in 32 patients with GIAs at our institute. Intraoperative Doppler sonography, indocyanine green, and postoperative angiography were used to assess the patency of the graft conduit and the stability of the aneurysm. Neurologic function was assessed with the modified Rankin Scale.The mean GIA size was 33.7 mm (range, 25.3–64 mm), and all showed a nonsaccular morphology, except for 1 patient who underwent a first attempt at surgical clipping of a saccular aneurysm. Complete occlusion (65.6%, n = 21) or great diminishment (28.1%, n = 9) of the GIA was shown in 30 patients and the graft patency rate was 90.6% (n = 29). No deaths resulting from bypass surgery occurred. Functionally favorable outcomes (modified Rankin Scale score of 0–2) were recorded in 65.6% of patients at discharge, and the rate increased to 71.9% at the most recent follow-up (mean, 40.6 months). Surgical-related complications involving hydrocephalus and ischemic and hemorrhagic episodes were encountered in 5 patients, but 4 had complete regression of their neurologic symptoms.Considering the grave natural history and treatment complexity of these lesions, this study showed satisfactory results in the treatment of GIAs with IMA bypass.

Internal Maxillary Artery-Middle Cerebral Artery Bypass

BACKGROUND:Internal maxillary artery (IMax)–middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a “keyhole” craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis.OBJECTIVE:To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass.METHODS:Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. Tokyo, Japan). Additionally, we studied the approach in a cadaveric specimen in preparation for microsurgical bypass.RESULTS:There were 4 cases in which the technique was used. One bypass was performed for flow augmentation in a hypoperfused hemisphere. The other 3 were performed as part of treatment paradigms for giant middle cerebral artery aneurysms. Vein grafts were used in all patients. The proximal anastomosis was performed in an end-to-side fashion in 1 patient and end-to-end in 3 patients. Intraoperative graft flow measured with the Transonic flow probe ranged from 20 to 60 mL/min. Postoperative angiography demonstrated good filling of the graft with robust distal flow in all cases. All patients tolerated the procedure well.CONCLUSION:IMax to middle cerebral artery subcranial-intracranial bypass is safe and efficacious. The laterotemporal fossa craniectomy technique resulted in reliable identification and wide exposure of the IMax, facilitating the proximal anastomosis.ABBREVIATIONS:EC-IC, extracranial-intracranialIMax, internal maxillary arteryMCA, middle cerebral arterySC-IC, subcranial-intracranialSTA, superficial temporal artery

Radial artery graft for bypass of internal maxillary artery to intracranial artery: a wise choice for complex intracranial aneurysms

Objective To report results of the internal maxillary artery bypass (MA)to the intracranial arteries with radial artery (RA) graft for complex aneurysms.Methods 22 patients with complex aneurysms underwent MA bypass with radial artery graft.Aneurysms were located in the cavernous segment of the internal carotid artery (C3) in 8 cases,middle cerebral artery (MCA) in 6 cases,ophthalmic segment in 4 cases,supraclinoid segment (C4) in 1 case,vertebrobasilar junction in 2 cases,and low basilar trunk in 1 case.Vital branches or perforating arteries arose at the origin of aneurysm bodies in 9 cases.4 patients had recurrent filling aneurysms or migration after coiling treatment.A 7 cm RA harvest was gathered from the forearm.An end-to-end anastomosis was first performed between the proximal radial artery graft and the proximal MA.In internal carotid aneurysms,the distal end of the RA graft was then anastomosed to the side of the temporal-occipital branch of the MCA,while the distal end of the RA graft was anastomosed to the side of the P2 segment of the PCA for vertebrobasilar aneurysms.After the completion of all anastomosis,the aneurysms were trapped in 16 cases,and proximal artery patent arteries was occluded only for creating reversal flow bypasses to aneurysms related to the small perforating arteries in 6 cases.Results 20 patients obtained excellent recovery; furthermore,patency of the bypass graft with elimination of aneurysms was confirmed in 20 patients.Patency of the bypass was unidentifiable in the remaining 2 patients,however,both patients did not have any symptoms without patent bypass in spite of the occlusion.22(100％)patients were followed-up between 3 months and 3 years after surgery.21 patients recovered their normal lives,while 1 patient still needed assistance for daily life for a disease unrelated to the surgery.Conclusion The selection of maxillary artery bypass to the intracranial artery distal to the aneurysm with subsequent reversal flow to the aneurysm body or trapping of the aneurysm should be an effective management in patients with unclipped giant aneurysm. Key words: Intracranial aneurysm; Cerebral revascularization; Vascular grafting; Maxillary artery; Radial artery