Maxillary Artery to Intracranial Bypass

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.

Maxillary artery utilization in subcranial-intracranial bypass procedures: a comprehensive systematic review and pooled analysis

The utilization of the internal maxillary artery (IMAX) in subcranial-intracranial bypass for revascularization in complex aneurysms, tumors, or refractory ischemia shows promise. However, robust evidence concerning its outcomes is lacking. Hence, the authors embarked on a systematic review with pooled analysis to elucidate the efficacy of this approach. We systematically searched PubMed, Embase, and Web of Science databases following PRISMA guidelines. Included articles used the IMAX as a donor vessel for revascularizing an intracranial area and reported at least one of the following outcomes: patency, complications, or clinical data. Favorable outcomes were defined as the absence of neurologic deficits or improvement in the baseline condition. Complications were considered any adverse event directly related to the procedure. Out of 418 retrieved articles, 26 were included, involving 183 patients. Among them, 119 had aneurysms, 41 experienced ischemic strokes (transient or not), 2 had arterial occlusions, and 3 had neoplasia. Furthermore, 91.8% of bypasses used radial artery grafts, and 87.9% revascularized the middle cerebral artery territory. The median average follow-up period was 12 months (0.3-53.1). The post-operation patency rate was 99% (95% CI: 97-100%; I2=0%), while the patency rate at follow-up was 82% (95% CI: 68-96%; I2=77%). Complications occurred in 21% of cases (95% CI: 9-32%; I2=58%), with no significant procedure-related mortality in 0% (95% CI: 0-2%; I2=0%). Favorable outcomes were observed in 88% of patients (95% CI: 81-96%; I2=0%), and only 3% experienced ischemia (95% CI: 0-6%; I2=0%). The subcranial-intracranial bypass with the IMAX shows excellent postoperative patency and considerable favorable clinical outcomes. While complications exist, the procedure carries a minimal risk of mortality. However, long-term patency presents heterogeneous findings, warranting additional research.

Maxillary Nerve as Landmark for Exposure of the Internal Maxillary Artery in Extracranial-Intracranial Bypass Surgery

OBJECTIVE

To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery.

METHODS

To explore the positional relationship between the IMA and the maxillary nerve and pterygomaxillary fissure, 11 formalin-fixed cadaveric specimens were dissected. Three bone windows of the middle fossa were created for further analysis. Then the IMA length that could be pulled up above the middle fossa was measured after different degrees of removal of bony structure. The IMA branches under each bone window were also explored in detail.

RESULTS

The top of the pterygomaxillary fissure was located 11.50 mm anterolateral to the foramen rotundum. The IMA could be identified just inferior to the infratemporal segment maxillary nerve in all specimens. After drilling of the first bone window, the IMA length that could be pulled above the middle fossa bone was 6.85 mm. After drilling of the second bone window and further mobilization, the IMA length that could be harvested was significantly longer (9.04 mm vs. 6.85 mm; P < 0.001). Removal of the third bone window did not significantly improve the IMA length that could be harvested.

CONCLUSIONS

The maxillary nerve could be used as a reliable landmark for the exposure of the IMA in the pterygopalatine fossa. With our technique, the IMA could be easily exposed and sufficiently dissected without zygomatic osteotomy and extensive middle fossa floor removal.

Double-barreled IMA-M2 and STA-MCA bypass in severe stenosis of terminal internal carotid artery: three case reports

EC-IC bypasses have been performed to treat complex aneurysms or moyamoya disease or atherosclerotic steno-occlusive disease. We report the three cases that underwent EC-IC revascularization of the IMA-M2 bypass using the radial artery graft concurrently after the STA-MCA anastomosis to prevent potential ischemic damage during the operation and augment more flow in terminal internal carotid artery stenosis. All patients experienced neither perioperative complications nor further events for a 3-month follow-up. The double-barreled IMA-M2 and STA-MCA bypass is a good option for substantial amount of EC-IC revascularization with minimizing ischemic injury and maximizing flow amount in patients with severe hemodynamic compromise.

Giant Aneurysm Management

The treatment of giant aneurysms has always been a challenge in the field of neurovascular disease. Giant aneurysms are larger in size and are associated with thrombosis development and the calcification of the aneurysmal wall and neck, which often interfere with direct clipping. Most giant aneurysms have a wide neck with an incomplete thrombus, making complete embolization almost impossible. Giant aneurysms of different sites have entirely different hemodynamic characteristics. Moreover, aneurysms at the same site may exhibit very different hemodynamics among different individuals. Therefore, careful assessment of each case is required before and during treatment to develop and carry out an individualized treatment plan.

Internal Maxillary Artery-Radial Artery-Middle Cerebral Artery Bypass and STA-MCA Bypass for the Treatment of Complex Middle Cerebral Artery Bifurcation Aneurysm: A Case Report

Background

Children's complex middle cerebral artery (MCA) aneurysm is a relatively rare occurrence. When the huge aneurysm is located in the MCA bifurcation with an inconspicuous neck and involving numerous arteries, intravascular interventional surgery or aneurysm clipping are often difficult treatment options. At this point, high flow bypass revascularization is necessary as a treatment to preserve cerebral blood flow. In recent years, the internal maxillary artery (IMA) has gradually become the mainstream donor artery of thw high flow bypass. We performed internal maxillary artery -radial artery-middle cerebral artery (IMA-RA-MCA) and superficial temporal artery-middle cerebral artery (STA-MCA) bypass as the treatment of a complex MCA bifurcation aneurysm in consideration of the patient's condition and the advantage of the IMA. According to the author, this case is the youngest reported case of IMA-RA-MCA bypass at present.

Case Description

A male child, 7 years and 8 months, was admitted to the hospital due to “recurrent headache for more than 9 months,” DSA indicated that there was a large wide-necked aneurysm at the bifurcation of the right MCA M1 segment, with a size of about 1.16*1.58*1.32 cm. The inflow path of the aneurysm was in front of M1 bifurcation, and one outflow path originated from the aneurysm body, and another small outflow path attached to the aneurysm body. After completing the preoperative evaluation, an extended pterional approach with zygomatic osteotomy was performed to fully expose the aneurysm and IMA, harvesting the left radial artery at the same time, then a STA-MCA bypass, IMA-RA-MCA bypass, and aneurysm trapping were performed. postoperative re-examination showed that bypass vessels and the distal middle artery vessels were patent and the aneurysm disappeared, the child has no neurological dysfunction.

Conclusions

IMA-RA-MCA bypass is an effective high-flow cerebral blood reconstruct scheme in the treatment of complex middle cerebral artery bifurcation aneurysms. This case can provide a reference for the surgical treatment of complex middle cerebral artery bifurcation aneurysms in children.

Advantages of petrosectomy for superficial temporal artery to superior cerebellar artery bypass based on three-dimensional distance measurements using cadaver heads

Superficial temporal artery (STA) to superior cerebellar artery (SCA) bypass is usually performed via the subtemporal approach (StA), anterior transpetrosal approach (ApA), or combined petrosal approach (CpA), but no study has yet reported a quantitative comparison of the operative field size provided by each approach, and the optimal approach is unclear. The objective of this study is to establish evidence for selecting the approach by using cadaver heads to measure the three-dimensional distances that represent the operative field size for STA-SCA bypass. Ten sides of 10 cadaver heads were used to perform the four approaches: StA, ApA with and without zygomatic arch osteotomy (ApA-ZO^- and ApA-ZO⁺), and CpA. For each approach, the major-axis length and the minor-axis length at the anastomosis site (La-A and Li-A), the major-axis length and the minor-axis length at the brain surface (La-B and Li-B), the depth from the brain surface to the anastomosis site (Dp), and the operating angles of the major axis and the minor axis (OAa and OAi) were measured. Shallower Dp and wider operating angle were obtained in the order CpA, ApA-ZO⁺, ApA-ZO^-, and StA. In all parameters, ApA-ZO^- extended the operative field more than StA. ApA-ZO⁺ extended La-B and OAa more than ApA-ZO^-, whereas it did not contribute to Dp and OAi. CpA significantly decreased Dp, and widened OAa and OAi more than ApA-ZO⁺. ApA and CpA greatly expanded the operative field compared with StA. These results provide criteria for selecting the optimal approach for STA-SCA bypass in light of an individual surgeon's anastomosis skill level.

Controversies and Advances in Adult Intracranial Bypass Surgery in 2020

Cerebral revascularization utilizing a variety of bypass techniques can provide either flow augmentation or flow replacement in the treatment of a range of intracranial pathologies, including moyamoya disease, intracranial atherosclerotic disease, and complex aneurysms that are not amenable to endovascular or simple surgical techniques. Though once routine, the publication of high-quality prospective evidence, along with the development of flow-diverting stents, has limited the indications for extracranial-to-intracranial (EC-IC) bypass. Nevertheless, advances in imaging, assessment of cerebral hemodynamics, and surgical technique have changed the risk-benefit calculus for EC-IC bypass. New variations of revascularization surgery involving multiple anastomoses, flow preserving solutions, IC-IC constructs, and posterior circulation bypasses have been pioneered for otherwise difficult to treat pathology including giant aneurysms, dolichoectasia, and medically refractory intracranial atherosclerosis. This review provides a practical update on recent advances in adult intracranial bypass surgery.

Imaging features of internal maxillary artery and extracranial middle meningeal artery and their relationships on head CTA

BACKGROUND

The internal maxillary artery and extracranial middle meningeal artery are vitally important. Anatomical studies of the relationship of between them using computed tomography angiography are rare.

MATERIAL AND METHODS

This study assessed 75 cases involving 150 sides. And the vascular diameters and lengths of the internal maxillary artery and middle meningeal artery were measured using a GE workstation. The distance between the zygomatic arch midpoint and the internal maxillary artery, the angle between the internal maxillary artery and middle meningeal artery were measured, and the middle meningeal artery branch and internal maxillary artery aneurysm were recorded. The internal maxillary artery course classifications were recorded. All of these parameters were statistically analysed.

RESULTS

Ages ranged from 18 to 72 (average 40.2) years, and there were 30 women (40%, 30/75) and 45 men (60%, 45/75). Internal maxillary artery length from its origin to middle meningeal artery origin was 1.37 ± 0.59 cm. The extracranial middle meningeal artery length was 1.79 ± 0.48 cm. The vessel diameters of internal maxillary artery origin, middle meningeal artery origin, and middle meningeal artery at the skull base were 2.93 ± 0.52 mm, 1.58 ± 0.43 mm, and 1.33 ± 0.43 mm, respectively. Among the 150 sides of internal maxillary artery course type, there were 138 superficial (92%, 138/150) and 12 (8%, 12/150) deep course cases. The angle between the internal maxillary artery and middle meningeal artery was 116.2 ± 35.76°.

CONCLUSIONS

The findings of this study elucidate the imaging features of the internal maxillary artery and extracranial middle meningeal artery and their relationships, which are helpful for the extracranial-intracranial bypass and endovascular treatment via the internal maxillary artery and middle meningeal artery.

Internal maxillary artery to middle cerebral artery bypass for a complex recurrent middle cerebral artery aneurysm: case report and technical considerations

We report the case of a 41-year-old male who presented with an enlarging aneurysm neck one year after clipping. The patient underwent an IMAX-MCA bypass followed by endovascular coil occlusion of the aneurysm neck incorporating an MCA branch origin. To our knowledge, this case represents the first documented IMAX-MCA bypass from a European centre. This case demonstrates that for neurosurgeons experienced in EC-IC bypass surgery, IMAX-MCA bypass is feasible and can be performed safely as long as careful attention is paid to anatomical landmarks and vascular anastomosis principles. CTA-based neuronavigation and micro-Doppler are essential intraoperative tools for identifying the IMAX.

Pterygo-Maxillary Fissure as a Landmark for Localization of Internal Maxillary Artery for Use in Extracranial-Intracranial Bypass

BACKGROUND

Internal maxillary artery (IMax) is a relatively new donor vessel used in the extracranial-intracranial bypass surgery. However, unfamiliarity and relatively elaborate techniques of its harvest precluded its widespread use.

OBJECTIVE

To present a simplified technique of IMax harvest based on constant anatomical landmarks without the need of extensive skull-base drilling while providing adequate space for proximal anastomosis.

METHODS

Cadaveric dissection on 4 cadaveric heads (8 sides) was performed. Zygomatic osteotomy was performed and temporal muscle was dissected off the zygomatic process of the frontal bone and the frontal process of the zygomatic bone and reflected inferiorly into the bony gap created by the zygomatic osteotomy. Posterior wall of the maxilla (PWoM) was palpated. Following PWoM inferiorly leads to pterygo-maxillary fissure (PMF), which is a constant landmark IMax passes through.

RESULTS

IMax was localized following this technique before its entrance into PMF in every specimen. Proximal dissection was carried on to the exposed adequate length of the vessel. Depending on the relationship with the lateral pterygoid muscle, this might need to be incised to allow for identification of the IMax. After its transection, proximal stump is mobilized superiorly into the surgical field. Clinical application of this technique was demonstrated on an aneurysm case.

CONCLUSION

Using the palpation of the PWoM as a landmark for localization of PMF facilitates harvesting of IMax without need for extensive skull-base drilling and shortens the time of the surgery.