Anterior Temporal Artery-to-Anterior Cerebral Artery Bypass: Anatomic Feasibility of a Novel Intracranial-Intracranial Revascularization Technique

Microsurgical Clipping and Bypass for Fusiform Middle Cerebral Artery Aneurysm: 2-Dimensional Operative Video

Fusiform middle cerebral artery (MCA) aneurysms that require treatment can often necessitate complex endovascular or microsurgical treatment. We present a case of a 25-yr-old female with an incidentally discovered left 14-mm fusiform MCA aneurysm incorporating the frontal MCA trunk origin in its dome. The location and anatomy were not favorable for endovascular treatment with flow diversion.  The patient was offered continued observation or microsurgical treatment. Direct clipping of this aneurysm was not possible. After a thorough discussion of the risks, benefits, indications, and natural history of the lesion, the patient desired to have the aneurysm treated given her young age, location, size of the aneurysm, and the significant clinical experience of the treating team in bypass surgery.  The patient underwent superficial temporal artery to frontal M2 (STA-FM2) direct bypass for flow replacement followed by microsurgical trapping and clip ligation. The patient was maintained on antiplatelet therapy preoperatively and postoperatively. The patient had a transient aphasia and mild right upper extremity weakness (4/5) in the immediate postoperative period, which fully recovered by the time of patient discharge. The case presentation, surgical anatomy, technique, and postoperative course and outcome are reviewed. The different strategies for bypass and clip ligation are reviewed with particular focus on the anatomic constraints for each bypass configuration. The outcomes of bypass surgery for MCA aneurysms are reviewed.1-7 The patient gave verbal consent for participating in the procedure, surgical video, and publication of their image.

Tailored Communicating Bypass for the Management of Complex Anterior Communicating Artery Aneurysms: "Flow-Counteraction" In Situ Bypass and Interposition Bypass Using Contralateral A2 Orifice as Donor Site

BACKGROUND

The use of bypass surgery for anterior communicating artery (ACOM) aneurysms is technically challenging. Communicating bypass (COMB), such as pericallosal artery side-to-side anastomosis, is the most frequently used and anatomically directed reconstruction option. However, in many complex cases, this technique may not afford a sufficient blood supply or necessitate sacrificing the ACOM and the eloquent perforators arising from it.

OBJECTIVE

To evaluate tailored COMB and propose a practical algorithm for the management of complex ACOM aneurysms.

METHODS

For 1 patient with an aneurysm incorporating the entire ACOM, conventional in Situ A3-A3 bypass was performed as the sole treatment in order to create competing flow for aneurysm obliteration, sparing the sacrifice of eloquent perforators. In situations in which A2s were asymmetric in the other case, the contralateral A2 orifice was selected as the donor site to provide adequate blood flow by employing a short segment of the interposition graft.

RESULTS

The aneurysm was not visualized in patients with in Situ A3-A3 bypass because of the "flow-counteraction" strategy. The second patient, who underwent implementation of the contralateral A2 orifice for ipsilateral A3 interposition bypass, demonstrated sufficient bypass patency and complete obliteration of the aneurysm.

CONCLUSION

The feasibility of conventional COMB combined with complete trapping may only be constrained to selected ideal cases for the treatment of complex ACOM aneurysms. Innovative modifications should be designed in order to create individualized strategies for each patient because of the complexity of hemodynamics and the vascular architecture. Flow-counteraction in Situ bypass and interposition bypass using the contralateral A2 orifice as the donor site are 2 novel modalities for optimizing the advantages and broadening the applications of COMB for the treatment of complex ACOM aneurysms.

Temporal Artery and Temporal Region Supplied by the Middle Cerebral Artery: An Anatomical Study

ABSTRACT

This study was conducted to describe in detail the branching patterns of cortical branches from the middle cerebral artery supplying the feeding of the temporal region, to define the arterial structure of temporal artery (TA) and to determine the effect of this arterial supply to the temporal region. The arteries of brains (n = 22; 44 hemispheres) were prepared for dissection after filling them with colored latex. TA was defined, and its classification was described, specifying its relationship with other cortical branches. A new classification was defined related to TA terminology. TA was found in 95% of cadavers, and it originated as an early branch in 75% and from the inferior trunk in 24% of cadavers. TA was classified as Type 0: No TA, Type I: single branch providing two cortical branches, Type II: single branch providing three or more cortical branches and Type III: double TA. Type I-TA (45%) was the most common, and Type II-TA arterial diameter was significantly larger than that of other types. All cadavers showed the cortical branches of temporal region from middle cerebral artery, anterior TA , middle TA, posterior TA and temporooccipital artery, except temporopolar artery (81%). Temporopolar artery, anterior TA, and middle TA primarily originated from TA, an early branch, but posterior TA and temporooccipital artery primarily originated from the inferior trunk. Detailed knowledge about cortical branches together with TA and also this region's blood supply would enable increased prediction of complications, especially in cases with these region-related pathologies, and would make interventions safer.

[Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]

Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.

Dissecting Aneurysm of the Anterior Temporal Artery: A Rare Case Report and Literature Review

Dissecting aneurysm located at the trunk of the anterior temporal artery (ATA) is an extremely rare entity of which only a few cases have ever been reported. As a result of the small caliber and supposed non-competency of the ATA, sacrificing of the artery distal to the aneurysm is the mainstay of treatment. In this report, we present a 28-year-old man who was admitted for a ruptured fusiform aneurysm of the left ATA. He underwent resection of the aneurysm combined with superficial temporal artery (STA)-ATA anastomosis. Histopathological study showed that the aneurysm was compliant with an artery dissection. The postoperative process was unremarkable and he was discharged with no neurological deficit. Follow-up angiography showed the anastomosis was patent. ATA is considered a non-competent intracranial artery. Although recently some investigators have conducted cadaveric studies using the ATA as a donor vessel for intracranial-intracranial (IC-IC) bypass, clinical consequences of ATA occlusion have not been reported yet. The supposed safety of ligation of ATA for IC-IC bypass was based on the fact that the anterior temporal lobectomy for temporal lobe epilepsy does not lead to major neurological deficits. This extrapolation could not be arbitrarily used in ATA occlusion for IC-IC bypass. STA-ATA anastomosis is a reasonable option in case of the ATA dissecting aneurysm.

Anatomical Assessment of the Temporopolar Artery for Revascularization of Deep Recipients

BACKGROUND

Intracranial-intracranial and extracranial-intracranial bypass options for revascularization of deep cerebral recipients are limited and technically demanding.

OBJECTIVE

To assess the anatomical feasibility of using the temporopolar artery (TPA) for revascularization of the anterior cerebral artery (ACA), posterior cerebral artery (PCA), and superior cerebellar arteries (SCA).

METHODS

Orbitozygomatic craniotomy was performed bilaterally on 8 cadaveric heads. The cisternal segment of the TPA was dissected. The TPA was cut at M3-M4 junction with its proximal and distal calibers and the length of the cisternal segment measured. Feasibility of the TPA-A1-ACA, TPA-A2-ACA, TPA-SCA, and TPA-PCA bypasses were assessed.

RESULTS

A total of 17 TPAs were identified in 16 specimens. The average distal TPA caliber was 1.0 ± 0.2 mm, and the average cisternal length was 37.5 ± 9.4 mm. TPA caliber was ≥ 1.0 mm in 12 specimens (70%). The TPA-A1-ACA bypass was feasible in all specimens, whereas the TPA reached the A2-ACA, SCA, and PCA in 94% of specimens (16/17). At the point of anastomosis, the average recipient caliber was 2.5 ± 0.5 mm for A1-ACA, and 2.3 ± 0.7 mm for A2-ACA. The calibers of the SCA and PCA at the anastomosis points were 2.0 ± 0.6 mm, and 2.7 ± 0.8 mm, respectively.

CONCLUSION

The TPA-ACA, TPA-PCA, and TPA-SCA bypasses are anatomically feasible and may be used when the distal caliber of the TPA stump is optimal to provide adequate blood flow. This study lays foundations for clinical use of the TPA for ACA revascularization in well-selected cases.