Anterior cerebral artery bypass for complex aneurysms: an experience with intracranial-intracranial reconstruction and review of bypass options

Three-Vessel Anastomosis for Direct Multiterritory Cerebral Revascularization: Case Series

BACKGROUND AND OBJECTIVE

Cerebral revascularization of multiple territories traditionally requires multiple constructs, serial anastomoses, or a combination of direct and indirect approaches. A novel 3-vessel anastomosis technique allows for direct, simultaneous multiterritory cerebral revascularization using a single interposition graft. We herein present our experience with this approach.

METHODS

Retrospective review of perioperative data and outcomes for patients undergoing multiterritory cerebral revascularization using a 3-vessel anastomosis from 2019 to 2023.

RESULTS

Five patients met inclusion criteria (median age 53 years [range 12-73]). Three patients with complex middle cerebral artery aneurysms (1 ruptured) were treated with proximal ligation or partial/complete clip trapping and multiterritory external carotid artery-M2-M2 revascularization using a saphenous vein interposition graft. Two patients with moyamoya disease, prior strokes, and predominately bilateral anterior cerebral artery hypoperfusion were treated with proximal superficial temporal artery-A3-A3 revascularization using a radial artery or radial artery fascial flow-through free flap graft. No patients experienced significant surgery-related ischemia. Bypass patency was 100%. One patient had new strokes from vasospasm after subarachnoid hemorrhage. One patient required a revision surgery for subdural hematoma evacuation and radial artery fascial flow-through free flap debridement, without affecting bypass patency or neurologic outcome. On hospital discharge, median Glasgow Outcome Scale and modified Rankin Scale scores were 4 (range 3-5) and 2 (range 0-5), respectively. On follow-up, 1 patient died from medical complications of their presenting stroke; Glasgow Outcome Scale and modified Rankin Scale scores were otherwise stable or improved.

CONCLUSION

The 3-vessel anastomosis technique can be considered for simultaneous revascularization of multiple intracranial territories.

In situ interposition bypass for complex intracranial aneurysms: A single-center experience and efficacy analysis

The purpose of this study was to investigate the application and efficacy analysis of in situ interposition bypass in complex intracranial aneurysms. This study retrospectively analyzed the clinical data of 21 patients with complex intracranial aneurysms treated with in situ interposition bypass grafting in the Department of Neurosurgery at Tianjin Huanhu Hospital from June 2015 to December 2022. The aneurysms were located in the middle cerebral artery in 16 cases, the anterior cerebral artery in 3 cases, the posterior cerebral artery in 1 case, and the posterior inferior cerebellar artery in 1 case. The interposition graft vessels were taken from the radial artery in 15 cases, the superficial temporal artery in 5 cases, and the occipital artery in 1 case. All patients underwent end-to-end anastomosis with in situ interposition bypass after aneurysm resection, including 13 cases of "I-shaped" type, 5 cases of "V-shaped" type, and 3 cases of "Y-shaped" type. Postoperative digital subtraction angiography (DSA) or computed tomography angiography (CTA) reviews were performed for all the patients, and modified Rankin Scale (mRS) score was used to assess patient prognosis. Three patients developed postoperative basal ganglia infarction and two of them recovered well. One case developed transient incomplete aphasia and one case developed mild hemiparesis, which recovered well after 3 months. The remaining 16 patients did not develop new neurological deficits. Postoperative DSA or CTA showed that the anastomosis of the bypass graft and the graft vessels were patent, and all aneurysms were completely eliminated. Regular postoperative follow-up ranged from 3 to 89 months, and no aneurysm recurred. The percentage of patients with mRS ≤ 2 at the final follow-up was 90.5%. Based on the experience of surgical treatment in our center, in situ interposition bypass technique is a safe and effective option for the treatment of some complex intracranial aneurysms.

Superficial temporal artery interposition bypass for the treatment of complex intracranial aneurysms: Flexible and creative options for flow preservation bypass

PURPOSE

Flow-preservation bypass is a treatment option for complex intracranial aneurysms (IAs) that cannot be managed with microsurgical clipping or endovascular treatment. Various bypass methods are available, including interposition grafts such as the radial artery or saphenous vein. Size discrepancy, invasiveness, and procedure complexity must be considered when using interposition grafts. We describe our experience of treating complex IAs using a superficial temporal artery (STA) interposition bypass.

METHODS

We retrospectively reviewed the medical records and operative videos of all patients who were treated for complex IAs at our center from January 2009 to December 2021 using cerebral revascularization. Clinical, radiological, and surgical findings of the cases that underwent STA interposition bypass were investigated.

RESULTS

Seventy-six bypass procedures were performed of which seven (9.2%) complex IAs were managed using STA interposition bypass. Of these 5 cases were of anterior cerebral artery, 1 of middle cerebral artery, and 1 of posterior inferior cerebellar artery aneurysm. There were no postoperative ischemic complications. Revision surgery for postoperative pseudomeningocele was performed in one case. The long-term bypass patency rate was 85.7% (6 out of 7) and good long-term aneurysm control was achieved in all cases, with a mean follow-up of 64 months.

CONCLUSIONS

When treating complex IAs, creative revascularization strategies are needed in selective cases for favorable outcomes. STA interposition graft bypass which can reduce the size discrepancy between the donor and recipient may be a less invasive, flexible, and practical option for treating complex IAs.

Hemodynamics of vascular shunts: trends, challenges, and prospects

Vascular bypass surgery takes a significant place in the treatment of vascular disease. According to various assessments, this type of surgery is associated with almost 20 % of all vascular surgery episodes (up to 23 % according to the Federal Neurosurgical Center of Novosibirsk). Even though the problem of using of vascular grafts is obvious and natural, many problems associated with them are not still elucidated. From the mechanics' point of view, a vascular bypass is a converging or diverging tee, and the functioning of such structures still does not have strict mathematical formulations and proofs in the general case, which forces many researchers to solve specific engineering problems associated with shunting. Mathematical modeling, which is the gold standard for virtual simulations of industrial and medical problems, faces great difficulties and limitations in solving problems for vascular bypasses. Complications in the treatment of the vascular disease may follow the difficulties in mathematical modeling, and the price can be a cardiac arrest or a stroke. This work is devoted to the main aspects of the medical application of vascular bypasses and their functioning as a mechanical system, as well the mathematical aspects of their possible setup.

Selective clipping of giant anterior communicating artery aneurysms remains a reliable therapeutic option

BACKGROUND

Giant anterior communicating artery (AcomA) aneurysm represent a significant surgical challenge. Our study aimed to discuss the therapeutic strategy in patients with a giant AcomA aneurysm treated by selective neck clipping through a pterional approach.

METHODS

Among all operated patients from an intracranial aneurysm between January 2015 and January 2022 (n = 726) in our institution, three patients with a giant AcomA aneurysm treated by neck clipping were included. Early (<7days) outcome was noted. Early postoperative CT scan was performed in all patients to detect any complications. Early DSA was also performed to confirm giant AcomA aneurysm exclusion. The mRS score was recorded 3 months after treatment. The mRS≤ 2 was considered as a good functional outcome. Control DSA was performed one year after treatment.

RESULTS

In the three patients, after a large frontopterional approach, a selective exclusion of their giant AcomA aneurysm was obtained after a partial pars orbitalis of the inferior frontal gyrus resection. Ischemic lesion was noted in 1 patient and chronic hydrocephalus in 2 patients with ruptured aneurysm. The mRS score after 3 months was good in 2 patients. Long term complete occlusion of the aneurysm were noted in the three patients.

CONCLUSION

Selective clipping of a giant AcomA aneurysm is a reliable therapeutic option after a careful evaluation of local vascular anatomy. An adequate surgical exposure is frequently obtained through an enlarged pterional approach with an anterior basifrontal lobe resection, especially in an emergency situation and/or in case of high position of anterior communicating artery.

A comparison study of vessel twisting by different microsurgical suture techniques in a chicken wing artery side to side bypass training model

OBJECTIVE

Microvascular anastomosis, particularly side-to-side (STS) bypass, is a complex surgical procedure. While several suture techniques exist, none of them is superior to the others. We assessed the association between various STS bypass techniques and vessel twisting using chicken wing training models.

METHODS

Three suture techniques were compared over an anterior wall suture procedure. The unidirectional continuous suture (UCS) group used a downward "right-to-left" continuous suture. The reverse continuous suture (RCS) group used a downward "left-to-right" continuous suture. The interrupted suture (IS) group used the standard interrupted suture. The number of samples in each of the three groups was 30 (n=90). We compared the incidence of vessel twisting and rotation angles across groups.

RESULTS

Vessel twisting occurred in 96.7%, 56.7%, and 0% of the cases in the UCS, IS, and RCS groups, respectively. The incidence of vessel twisting differed significantly in all 3 groups (p<0.001), with an apparent trend (p=0.002). The mean rotation angles were 201˚±90.6˚, 102˚±107.6˚, and 0˚ in the UCS, IS, and RCS groups, respectively, which were significantly different (p<0.001). On excluding cases without twisting, the rotation angles of twisted vessels in the UCS and IS groups were 207.9˚±83.7˚ and 180˚±77.9˚, respectively, which yielded a significant difference between these groups (p<0.001).

CONCLUSIONS

We found that the incidence and trend of vessel twisting differed significantly across suture techniques. The RCS technique may aid in preventing vessel twisting in the STS bypass procedure.

External carotid artery-radial artery graft-posterior cerebral artery bypass for complex vertebrobasilar aneurysms: efficacy and analysis of outcome in a single center

The purpose of this research was to demonstrate the effectiveness and clinical outcome of an external carotid artery-radial artery graft-posterior cerebral artery (ECA-RAG-PCA) bypass in the treatment of complex vertebrobasilar artery aneurysms (VBANs) in a single-center retrospective study. An ECA-RAG-PCA bypass may be a last and very important option in the treatment of complex VBANs when conventional surgical clipping or endovascular interventions fail to achieve the desired outcome. This study retrospectively analyzed the clinical presentation, case characteristics, aneurysm location, size and morphology, choice of surgical strategy, complications, clinical follow-up, and prognosis of the patients enrolled. The data involved were analyzed by the appropriate statistical methods. A total of 24 patients with complex VBANs who met the criteria were included in this study. Eighteen (75.0%) were male and the mean age was 54.1 ± 8.83 years. The aneurysms were located in the vertebral artery, the basilar artery, and in the vertebrobasilar artery with simultaneous involvement. All patients underwent ECA-RAG-PCA bypass surgery via an extended middle cranial fossa approach, with 8 (33.3%) undergoing ECA-RAG-PCA bypass only, 3 (12.5%) undergoing ECA-RAG-PCA bypass combined with aneurysm partial trapping, and 12 (50.0%) undergoing ECA-RAG-PCA bypass combined with proximal occlusion of the parent artery. The average clinical follow-up was 22.0 ± 13.35 months. The patency rate of the high-flow bypass was 100%. At the final follow-up, 15 (62.5%) patients had complete occlusion of the aneurysm, 7 (29.2%) patients had subtotal occlusion of the aneurysm, and 2 (8.3%) patients had stable aneurysms. The rate of complete and subtotal occlusion of the aneurysm at the final follow-up was 91.7%. The clinical prognosis was good in 21 (87.5%) patients and no procedure-related deaths occurred. Analysis of the good and poor prognosis groups revealed a statistically significant difference in aneurysm size (P = 0.034, t-test). Combining the results of this study and the clinical experience of our center, we propose a surgical algorithm and strategy for the treatment of complex VBANs.The technical approach of ECA-RAG-PCA bypass for complex VBANs remains important, even in an era of rapid advances in endovascular intervention. When conventional surgical clipping or endovascular intervention has failed, an ECA-RAG-PCA bypass plays a role that cannot be abandoned and is a very important treatment option of last resort.

The application of high-resolution vessel wall imaging in the in situ bypass surgeries for complex anterior cerebral artery aneurysms

OBJECTIVE

Complex anterior cerebral artery (ACA) aneurysms are still technically challenging to treat. Bypass surgery is needed to achieve aneurysm obliteration and ACA territory revascularization. Severe atherosclerosis of aneurysm walls can cause clip slippage, intraoperative rupture, postoperative ischemic events. How to assess the atherosclerotic changes in vascular walls by high-resolution vessel wall magnitude resonance imaging (VWI) is the key question in complex ACA aneurysm surgical management.

METHODS

This retrospective single-center study included eight patients diagnosed with complex anterior cerebral arteries admitted to our hospital for bypass surgery from January 2019 to April 2022. We discussed the application of VWI in aneurysms treated with in situ bypass and reviewed previous experience of revascularization strategies for complex ACA aneurysms.

RESULTS

In this study, we treated 8 cases of complex ACA aneurysms (3 communicating aneurysms/5 postcommunicating aneurysms) over the prior one year. In situ side-to-side anastomosis (1 A2-to-A2/6 A3-to-A3) was performed in seven cases, and trapping combined with excision was performed in another case. Following bypass, complete trapping was performed in 4 cases, and proximal clipping was performed in 3 cases. No surgery-related neurological dysfunctions were observed. The final modified Rankin scale was 0 in seven of the eight cases and 2 in one case.

CONCLUSION

High-resolution VWI, as a favorable preoperative assessment tool, provides insight into patient-specific anatomy and microsurgical options before operations, which can help neurosurgeons develop individualized and valuable surgical plans.

Combined open revascularization and endovascular treatment of complex intracranial aneurysms: case series

Background and purpose

The treatment of complex intracranial aneurysms can be challenging with stand-alone open or endovascular techniques, particularly after rupture. A combined open and endovascular strategy can potentially limit the risk of extensive dissections with open-only techniques, and allow for aggressive definitive endovascular treatments with minimized downstream ischemic risk.

Materials and methods

Retrospective, single-institution review of consecutive patients undergoing combined open revascularization and endovascular embolization/occlusion for complex intracranial aneurysms from 1/2016 to 6/2022.

Results

Ten patients (4 male [40%]; mean age 51.9 ± 8.7 years) underwent combined open revascularization and endovascular treatment of intracranial aneurysms. The majority of aneurysms, 9/10 (90%), were ruptured and 8/10 (80%) were fusiform in morphology. Aneurysms of the posterior circulation represented 8/10 (80%) of the cases (vertebral artery [VA] involving the posterior inferior cerebellar artery [PICA] origin, proximal PICA or anterior inferior cerebellar artery/PICA complex, or proximal posterior cerebral artery). Revascularization strategies included intracranial-to-intracranial (IC-IC; 7/10 [70%]) and extracranial-to-intracranial (EC-IC; 3/10 [30%]) constructs, with 100% postoperative patency. Initial endovascular procedures (consisting of aneurysm/vessel sacrifice in 9/10 patients) were performed early after surgery (0.7 ± 1.5 days). In one patient, secondary endovascular vessel sacrifice was performed after an initial sub-occlusive embolization. Treatment related strokes were diagnosed in 3/10 patients (30%), largely from involved or nearby perforators. All bypasses with follow-up were patent (median 14.0, range 4-72 months). Good outcomes (defined as a Glasgow Outcomes Scale ≥4 and modified Rankin Scale ≤2) occurred in 6/10 patients (60%).

Conclusion

A variety of complex aneurysms not amenable to stand-alone open or endovascular techniques can be successfully treated with combined open and endovascular approaches. Recognition and preservation of perforators is critical to treatment success.

The changing landscape of cerebral revascularization surgery: A United Kingdom experience

Objective

We describe the chronological trends in cerebral revascularization surgery through a single-surgeon experience; and we review whether in the context of giant and fusiform cerebral aneurysms, flow-diverting stents have impacted on the use of cerebral revascularization surgery.

Methods

We review our single institution prospectively collected database of cerebral revascularization procedures between 2006 and 2018. Comparing this to our database of flow-diverting endovascular stent procedures, we compare the treatment of fusiform and giant aneurysms. We describe patient demographics, procedural incidence, complications, and outcomes.

Results

Between 2006 and 2018, 50 cerebral revascularization procedures were performed. The incidence of cerebral revascularization surgery is declining. In the context of giant/fusiform aneurysm treatment, the decline in cerebral revascularization is accompanied by a rise in the use of flow-diverting endovascular stents. Thirty cerebral revascularizations were performed for moyamoya disease and 11 for giant/fusiform aneurysm. Four (14%) direct bypass grafts occluded without neurological sequela. Other morbidity included hydrocephalus (2%), transient ischemic attacks (2%), and ischemic stroke (2%). There was one procedure-related mortality (2%). Flow-diverting stents were inserted for seven fusiform and seven giant aneurysms. Comparing the treatment of giant/fusiform aneurysms, there was no significant difference in morbidity and mortality between cerebral revascularization and flow-diverting endovascular stents.

Conclusion

We conclude that with the decline in the incidence of cerebral revascularization surgery, there is a need for centralization of services to allow high standards and outcomes to be maintained.

Comparison of Pipeline Embolization Device and Traditional Endovascular Therapeutic Approaches in Distal Cerebral Circulation Aneurysms Using Propensity Score Matching Analysis

Background

Coiling and stent-assisted coiling remain the first-line treatments for distal cerebral circulation aneurysms (DCCAs). The off-label use of the pipeline embolization device (PED) for these aneurysms has been explored recently but remains controversial.

Objective

To compare traditional endovascular therapeutic approaches (coiling and stent-assisted coiling) and PED for DCCAs in a multicenter cohort of patients.

Methods

A multicenter, retrospective cohort comparison study was conducted that included consecutive patients with unruptured DCCAs treated with either traditional endovascular therapeutic approaches or PED placement at three centers between 2016 and 2020. Propensity score matching analysis was applied to adjust for baseline risk factors between the PED and TET groups. Matching was based on age, sex, aneurysm size, location, morphology, adjunctive coiling, treatment history, and preoperative mRS score.

Results

In total, 209 patients with DCCAs treated with PED or traditional endovascular therapeutic approaches were identified. Thirty-seven patients underwent PED treatment, and 172 patients underwent traditional endovascular therapeutic approaches. After propensity score matching, 37 aneurysm pairs were matched, and the baseline characteristics of the patients were balanced between the groups. The complete occlusion rate between PED and traditional endovascular therapeutic approach in both matched cohorts (91.7 vs. 92.3%, p > 0.78) was similar. The rate of periprocedural treatment-related complications in both the PED and traditional endovascular therapeutic groups was 13.5%. Univariate analysis identified average parent vessel diameter as the only predictor of complete occlusion (p = 0.038).

Conclusions

PED is a viable option for treating DCCAs by providing occlusion and complication rates similar to those of traditional endovascular therapeutic approaches. A rigid patient selection procedure and proper planning should be undertaken to reduce treatment-related complications.

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.

Recovery of Visual Loss Following Internal Trapping of Anterior Cerebral Artery (A1 Segment) for Partially Thrombosed Large Anterior Communicating Artery Aneurysm: A Case Report

A 60-year-old woman, who experienced progressive right visual loss, was diagnosed with an unruptured large cerebral aneurysm. Magnetic resonance imaging (MRI) and angiography revealed a large partially thrombosed anterior communicating artery (Acom) aneurysm. The aneurysmal neck was located at the junction of the left A1–A2 segments, and the aneurysmal dome communicated with the right A1–A2 junction by the Acom. Endovascular treatment using the flow alteration technique was selected. Following an oral antiplatelet therapy for 9 days, balloon test occlusion (BTO) of the medial portion of the left A1 segment was performed under local anesthesia. After confirming the tolerance of the BTO, internal trapping of the medial portion of the left A1 segment by detachable coils was performed following intra-aneurysmal coil embolization. Oral antiplatelet treatment was continued for 19 days postoperatively. Within 3 months following the operation, her right visual acuity dramatically improved to the original level. Owing to aneurysmal recanalization and the disappearance of the thrombus, the second and third embolization was performed through the Acom route, 4 months and 3 years following the first embolization, respectively, and followed up for an additional 7 years by MRI; no deterioration of her visual acuity and no aneurysmal recanalization was observed. Thus, endosaccular embolization combined with flow alteration is considered a useful alternative treatment for large and partially thrombosed Acom aneurysms.

A Case of Ruptured Anterior Cerebral Artery Dissection Prevented from Re-rupture with Stenting and Modification of Antiplatelet Agents

A case of ruptured anterior cerebral artery (ACA) dissection was treated with multiple neck-bridge stents, with modification of antiplatelet administration according to changes in the shape of the aneurysm in the acute phase. A 67-year-old woman presented with severe subarachnoid hemorrhage and fusiform dilatation was observed in the left ACA between the A1 and A2 segments. The use of stents in the acute phase is associated with high risk of ischemic complications. Prasugrel administration, which is considered to have low drug resistance, may have allowed safe stent use in the acute phase.

Coding cerebral bypasses: a proposed nomenclature to better describe bypass constructs and revascularization techniques

OBJECTIVE

Bypass surgery has evolved into a complex surgical art with a variety of donor arteries, recipient arteries, interpositional grafts, anastomoses, and suturing techniques. Although innovation in contemporary bypasses has increased, the literal descriptions of these new bypasses have not kept pace. The existing nomenclature that joins donor and recipient arteries with a hyphen is simplistic, underinformative, and in need of improvement. This article proposes a nomenclature that systematically incorporates anatomical and technical details with alphanumeric abbreviations and is a clear, concise, and practical "code" for bypass surgery.

METHODS

Detailed descriptions and illustrations of the proposed nomenclature, which consists of abbreviations for donor and recipient arteries, arterial segments, arteriotomies, and sides (left or right), with hyphens and parentheses to denote the arteriotomies joined in the anastomosis and brackets and other symbols for combination bypasses, are presented. The literature was searched for articles describing bypasses, and descriptive nomenclature was categorized as donor and recipient arteries (donor-recipient), donor-recipient with additional details, less detail than donor-recipient, and complete, ambiguous, or descriptive text.

RESULTS

In 483 publications, most bypass descriptions were categorized as donor-recipient (335, 69%), with superficial temporal artery-middle cerebral artery bypass described most frequently (299, 62%). Ninety-seven articles (20%) used donor-recipient descriptions with additional details, 45 (9%) were categorized as ambiguous, and none contained a complete bypass description. The authors found the proposed nomenclature to be easily applicable to the more complex bypasses reported in the literature.

CONCLUSIONS

The authors propose a comprehensive nomenclature based on segmental anatomy and additional anastomotic details that allows bypasses to be coded simply, succinctly, and accurately. This alphanumeric shorthand allows greater precision in describing bypasses and clarifying technical details, which may improve reporting in the literature and thus help to advance the field of bypass surgery.

Revascularization to the ACA: effectiveness and variation of the STA-RAG-A3 bonnet bypass

BACKGROUND

The effectiveness of bypass surgery in patients with atherothrombotic ischemia in the anterior cerebral artery (ACA) domain remains unclear. In this study, three cases with ischemia in the ACA territory underwent revascularization surgery using superficial temporal artery (STA)-radial artery graft (RAG)-A3 (pericallosal artery) bonnet bypass. Herein, we discuss the effectiveness and variations of this approach.

METHODS

Among 182 consecutive patients with atherothrombotic ischemic stroke admitted to the NTT Medical Center, Tokyo, from April 2017 to May 2021, three patients with hemodynamic insufficiency in the extensive ACA territory beyond the recent infarct area were treated using STA-RAG-A3 bonnet bypass.

RESULTS

One patient with bilateral severe cerebral blood flow (CBF) deficiency required additional A3-A3 and STA-middle cerebral artery single bypass in conjunction with STA-RAG-A3 bypass. There were no complications associated with the surgical procedure. The patients' hemodynamic study results and neurocognitive performances improved dramatically after surgery.

CONCLUSION

Our results suggest the efficacy of STA-RAG-A3 bypass for atherothrombotic ACA ischemia. However, because the number of cases was too small to generalize our results, more cases and thorough pre- and postoperative hemodynamic studies are necessary to prove the validity of the approach.

Superficial Temporal Artery Extended Interposition Graft to Anterior Cerebral Artery Bypass for the Treatment of a Large Fusiform Distal Anterior Cerebral Artery Aneurysm: 2-Dimensional Operative Video

Fusiform aneurysms of the distal anterior cerebral artery (DACA) are infrequent. Clip reconstruction and sequential progressive clipping have been described in the management of giant thrombosed DACA aneurysms.1,2 Customized revascularization with bypass, side-to-side anastomosis, and trapping of the aneurysmal segment have also been performed for treating DACA aneurysms.3-12 We present a 2-dimensional operative video of superficial temporal artery (STA) to distal anterior cerebral artery bypass, followed by trapping of the aneurysm-bearing segment. A 57-yr-old lady presented with a large ruptured subcallosal fusiform DACA aneurysm (WFNS grade 1, Fisher grade 1). Angiography revealed a 1.3 × 0.9 cm fusiform aneurysm in the DACA.  Informed consent was secured from the patient and her family for the surgery and permission was obtained for the publication of the patient's image/surgical video. The frontal and parietal branches of the STA were dissected. The parietal branch was explanted and used as a free interposition graft between the frontal branch (end-to-end anastomosis) and calloso-marginal artery (end-to-side anastomosis). After confirming blood flow through the bypass using Doppler, the aneurysm was trapped and excised.  The patient had an uneventful recovery. Her postoperative computed tomography (CT) head revealed no evidence of neurological insult. The patency of the bypass conduit and the complete removal of the aneurysm were confirmed using a digital subtraction angiogram. Histopathological examination revealed an eccentric atheromatous plaque with a lipid core. There was no evidence of intraplaque hemorrhage. This extended STA graft utilizing the frontal and parietal branches of the STA, and its implantation into the distal ACA, offers a novel bypass strategy for tackling fusiform aneurysms of the DACA. Anastomosis to the calloso-marginal artery ensured perfusion of the ACA territory through the pericallosal artery during temporary occlusion.

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.

In Situ Side-to-Side Pericallosal-Pericallosal Artery and Callosomarginal-Callosomarginal Artery Bypasses for Complex Distal Anterior Cerebral Artery Aneurysms: A Technical Note

BACKGROUND

Despite surgical and endovascular technical improvements over the last decades, the treatment of complex aneurysms of the distal anterior cerebral artery (ACA) is very challenging for both vascular neurosurgeons and interventional neuroradiologists. Furthermore, the interpersonal anatomic variability requires, most of the time, a tailored planning.

OBJECTIVE

To describe a novel technique of bypasses in the territory of ACA to protect the brain territory distal to the aneurysm.

METHODS

A 53-yr-old male with a large complex fusiform aneurysm of the left distal A2 segment of the ACA, involving the origin of the callosomarginal and pericallosal arteries, was judged not suitable for a single procedure (endovascular or neurosurgical). Two side-to-side bypasses were performed in a single surgery to connect the pericallosal and callosomarginal arteries of both sides, distally to the aneurysm. Subsequently, an endovascular embolization of the aneurysm was achieved with coils.

RESULTS

The patency of the microanastomoses, performed in the anterior interhemispheric fissure, was positively evaluated intraoperatively with indocyanine green and fluorescein videoangiography. The aneurysm sac, together with proximal A2 segment, was completely occluded with platinum coils. At the last follow-up, computed tomography angiography confirmed the patency of both bypasses, without any sign of aneurysm recanalization. The patients never complained of any focal neurological deficits or worsening of clinical status.

CONCLUSION

We present an elegant and innovative solution to completely protect the distal ACA territory in cases of complex aneurysm involving the origin of both callosomarginal and pericallosal arteries.

[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.

A3-A3 Anastomosis in the Management of Complex Anterior Cerebral Artery Aneurysms: Experience With in Situ Bypass and Lessons Learned From Pseudoaneurysm Cases

BACKGROUND

A3-A3 side-to-side bypass is an intracranial-to-intracranial (IC-IC) revascularization option when aneurysm treatment involves occlusion of one anterior cerebral artery (ACA).

OBJECTIVE

To describe applications of A3-A3 side-to-side bypass in the management of ACA true and pseudoaneurysms along with a review of pertinent literature.

METHODS

Six consecutive patients undergoing an A3-A3 bypass as part of their aneurysm management, representing a single-surgeon experience in a 2-yr period, were included in this retrospective review of a prospectively collected database.

RESULTS

Three male and three female patients with a median (range) age of 41.5 (11-69) years representing four ruptured and two unruptured aneurysms were included. Two of the aneurysms were communicating while four were postcommunicating from which three were pseudoaneurysms. Complete aneurysm obliteration was achieved in 5/6 cases. Bypass patency was evaluated in all cases intra- and postoperatively. Good outcomes (modified Rankin Scale score ≤ 2) at follow-up were observed in 4/6 patients. An improvement in mRS scores at the most recent follow-up as compared to preoperative status was achieved in three while scores remained the same in two patients. Ischemic complications related to aneurysm treatment were observed in two patients, both of which achieved good functional recovery upon follow-up. One patient deceased postoperatively due to progression of vasospasm-related infarcts.

CONCLUSION

A3-A3 bypass in the management of true as well as pseudoaneurysms of the ACA can achieve good postoperative outcomes in selected patients. Prompt diagnosis and aggressive surgical treatment needs to be pursued if a vessel injury with pseudoaneurysm formation is suspected.

[Resection of a giant fusiform aneurysm of the pericallosal artery with «hemi-bonnet bypass» procedure (case report and literature review)]

A 30-year-old woman with giant fusiform aneurysm of the azygos anterior cerebral artery is reported. Clipping of the aneurysm followed by modeling of pericallosal artery was performed in 2017. However, further enlargement of the aneurysm has been observed for subsequent 2 years. The patient underwent redo surgery with excision of the aneurysm followed by «hemi-bonnet bypass» procedure (anastomosis between superficial temporal artery and anterior cerebral artery with radial artery as an interposition graft). Literature data on reconstructive surgery in the treatment of complex pericallosal artery aneurysms are reviewed.

Carotid artery occlusion and revascularization in the management of meningioma

As the carotid artery courses through the skull base and into the subarachnoid space, it lies in close proximity to regions notorious for meningioma growth. Although infrequent, the growth of these tumors can compromise blood flow through the artery, putting the downstream territory at risk for stroke. In other scenarios, removal of these tumors sometimes requires planning to accomplish both tumor removal and revascularization in the same procedure when then the tumor invades the artery. Since revascularization (bypass surgery) is best performed on a nonemergent basis, it should be given consideration in the preoperative setting. Crisis situations related to intraoperative iatrogenic injury are managed methodically by determining the site of vessel injury and then deciding whether a primary repair or bypass procedure is necessary. The mainstays of revascularization procedures of the carotid artery include flow augmentation and flow replacement, with the superficial temporal artery and external carotid artery being the donor sites, respectively. Although tumor control or cure can be accomplished with surgical, radiosurgical, or combined methods, attention to vascular structures and ensuring blood flow preservation as part of the treatment plan is an important tenet in meningioma surgery.

[Giant thrombosed aneurysm of the pericallosal artery: clinical observation, literature review]

Are characterized by Distal giant aneurysms of the anterior cerebral artery are an extremely rare pathology. There are less than 40 cases of this disease described in literature.

OBJECTIVE

The aim of the article is to present the clinical observation of a successfully treated giant aneurysm of the pericallosal artery in a 58-year-old man, and also analyze the publications on distal cerebral aneurysms.

MATERIAL AND METHODS

The data of a patient hospitalized with a suspected tumor of the left brain hemisphere spreading to the left lateral ventricle is presented. Repeated MRI suggests a giant subtotal thrombotic aneurysm of the left perical artery, which was confirmed by SCT angiography. The patient underwent aneurysm treping-cliping with dissection of the aneurysm sac. In the analysis of the literature it was shown that the frequency of perical artery aneurysms varies from 5.3-6.0%, and giant aneurysms of this localization are extremely rare and occur in 1-4.5% of all perical artery aneurysms. Unlike distal anterior cerebral artery aneurysms of small and medium size, giant aneurysms are characterized by pseudotumorrhagic symptoms, which causes diagnostic difficulties.

CONCLUSION

It is necessary to remember about the diagnostic difficulties caused by the pseudotumorrhosis of the giant aneurysms of the pericallosal artery and the frequent negative angiography data due to total thrombosis of the aneurysmal sac. The gold standard is microsurgical clipping with excision of the aneurysmal sac. The prognosis for this group of patients is favorable.

Long-term patency in cerebral revascularization surgery: an analysis of a consecutive series of 430 bypasses

OBJECTIVE

Large cohort analysis concerning intracerebral bypass patency in patients with long-term follow-up (FU) results is rarely reported in the literature. The authors analyzed the long-term patency of extracranial-to-intracranial (EC-IC) and intracranial-to-intracranial (IC-IC) bypass procedures.

METHODS

All intracranial bypass procedures performed between 1997 and 2017 by a single surgeon were screened. Patients with postoperative imaging (CT angiography, MR angiography, or catheter angiography) were included and grouped into immediate (< 7 days), short-term (7 days-1 year), and long-term (> 1 year) FU groups. Data on patient demographics, bypass type, interposition graft type, bypass indication, and radiological patency were collected and analyzed with univariate and multivariate (adjusted multiple regression) models.

RESULTS

In total, 430 consecutive bypass procedures were performed during the study period (FU time [mean ± SD] 0.9 ± 2.2 years, range 0-17 years). Twelve cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 97%. All bypass occlusions occurred within a week of revascularization. All patients in the short-term FU group (n = 76, mean FU time 0.3 ± 0.3 years) and long-term FU group (n = 89, mean FU time 4.1 ± 3.5 years) had patent bypasses at last FU. Patients who presented with aneurysms had a lower rate of patency than those with moyamoya disease or chronic vessel occlusion (p = 0.029). Low-flow bypasses had a significantly higher patency rate than high-flow bypasses (p = 0.033). In addition, bypasses with one anastomosis site compared to two anastomosis sites showed a significantly higher bypass patency (p = 0.005). No differences were seen in the patency rate among different grafts, single versus bilateral, or between EC-IC and IC-IC bypasses.

CONCLUSIONS

The overall bypass patency of 97% indicates a high likelihood of success with microsurgical revascularization. Surgical indication (ischemia), low-flow bypass, and number of anastomosis (one site) were associated with higher patency rates. EC-IC and IC-IC bypasses have comparable patency rates, supporting the use of intracranial reconstructive techniques. Bypasses that remain patent 1 week postoperatively and have the opportunity to mature have a high likelihood of remaining patent in the long term. In experienced hands, cerebral revascularization is a durable treatment option with high patency rates.

Flow diversion for small caliber vessel aneurysms: efficacy, safety, and functional outcome

BACKGROUND

Flow-diverting stents had gained prominence among neurointerventionalists. Aneurysms originating from distal vessels, particularly dissecting or fusiform, pose more technical challenges. The aim of the following single center large series was to report the safety, efficacy, and functional outcome of flow diversion for aneurysms originating from small caliber vessel and compare to proximal vessels group.

METHODS

A retrospective chart review of a prospectively maintained database for subjects treated with flow diversion from 2010-2019.

RESULTS

A total of 598 aneurysms were treated during a period extending from 2010-2019 (87.8% large caliber group versus 12.20% small caliber group); 84.28% (N.=504) were females and the average age was 55.5 years. Ischemic stroke occurred at a rate of 2.99% with a non-significant difference between both groups. Delayed aneurysmal rupture and distal intraparenchymal bleed occurred at a rate of 3.70% with a non-significant difference between both groups. Complete aneurysms occlusion was seen at a rate of 75.3% with a non-significant difference between both groups. Morbidity rate occurred at a rate of 5.8% with non-significant difference between both groups. Multivariate logistic regression showed that small vessel was an independent predictor of aneurysm obliteration with a 2.6-fold-higher likelihood.

CONCLUSIONS

Flow-diverting stents are being used to treat diverse types of aneurysms and in various locations, in distal small caliber vessels where other treatment options pose a considerable risk. Small caliber group had similar complication and occlusion rates compared to proximal vessel group.

Radial Artery Fascial Flow-Through Free Flap for Complex Cerebral Revascularization: Technical Notes and Long-Term Neurologic and Radiographic Outcomes

BACKGROUND

Surgical innovation is critical for the management of challenging cerebrovascular pathology. Flow-through free flaps are versatile composite grafts that combine viable tissue with a revascularization source. Neurosurgical experience with these flaps is limited.

OBJECTIVE

To provide an in-depth technical description of the radial artery fascial (and fasciocutaneous) flow-through free flap (RAFF and RAFCF, respectively) for complex cerebral revascularizations.

METHODS

An Institutional Review Board-approved, prospective database was retrospectively reviewed to identify patients that underwent extracranial-to-intracranial cerebral bypass with a RAFF or RAFCF. Patient demographics, underlying pathology, surgical treatment, complications, and outcomes were recorded.

RESULTS

A total of 4 patients were treated with RAFFs or RAFCFs (average age 40 ± 8.8 yr). Two patients with progressive moyamoya disease involving multiple vascular territories with predominantly anterior cerebral artery (ACA) symptoms and flow alterations underwent combined direct ACA and indirect middle cerebral artery (MCA) bypass with a RAFF. The third patient with moyamoya disease and concomitant proximal fusiform aneurysms requiring internal carotid artery sacrifice underwent dual direct ACA and MCA bypass and indirect MCA revascularization with posterior tibial artery and RAFF grafts. The fourth patient with a large MCA bifurcation aneurysm and recurrent wound complications underwent a direct MCA bypass and complex wound reconstruction using a RAFCF. Good neurologic outcomes (Glasgow Outcomes Scale score ≥4 at discharge) were achieved in all patients. There were no perioperative surgical complications, and graft patency was confirmed on long-term follow-up.

CONCLUSION

The RAFF and RAFCF are versatile grafts for complex cerebral revascularizations.

Pipeline for Distal Cerebral Circulation Aneurysms

BACKGROUND

Pipeline embolization device (PED; Medtronic, Dublin, Ireland) utilization is not limited to the treatment of giant wide-necked aneurysms. It has been expanded to handle small blisters, fusiforms, and dissecting intracranial aneurysms.

OBJECTIVE

To report the use of the PED in various off-label distal cerebral circulation (DCC) arteries with a follow-up to assess clinical outcomes.

METHODS

Between 2011 and 2016, of 437 consecutive patients, 23 patients with aneurysms located in DCCs were treated with PED. Data on patient presentation, aneurysm characteristics, procedural outcomes, postoperative course, and aneurysm occlusion were gathered. To control confounding, we used multivariable logistic regression and propensity score conditioning.

RESULTS

A total of 437 patients (mean age 52.12 years; 62 women [14.2%]) underwent treatment with PED in our institution. Twenty-three of 437 (5.2%) received a pipeline in a distal artery: 11/23 middle cerebral artery, 6/23 posterior cerebral artery, 3/23 anterior cerebral artery (A1/A2, pericallosal artery), and 3/23 posterior inferior cerebellar artery. Twenty percent of the aneurysms were treated in the past, 10% had previously ruptured, and 5.9% ruptured at presentation to our hospital. The mean aneurysm size was 9.0 ± 6 mm. The mean follow-up was 12 mo (SD = 12.5). In multivariable logistic regression, no associations were found between PED deployment in DCCs and aneurysm occlusion or thromboembolic complications. PED use in DCC was associated with a good clinical outcome. Twenty-two people of 23 (95%) had a good clinical outcome in the latest follow-up.

CONCLUSION

Treatment of DCC aneurysms with PED is technically challenging mainly because of the small caliber and tortuosity of the parent arteries. The results of this study further support the safety of flow diverters in the treatment of various distal aneurysms.

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.

Side-to-Side Anastomosis Training Model Using Rat Common Carotid Arteries

BACKGROUND

The side-to-side anastomosis is one of the difficult bypass configurations that may be used in various complex cerebral vascular and neoplastic cases. Few pure arterial models exist for practicing this bypass subtype.

OBJECTIVE

To provide an optimized side-to-side anastomosis training model using rat common carotid arteries (CCA).

METHODS

Bilateral CCAs were exposed in the neck of 10 anesthetized Sprague-Dawley rats. The arteries were juxtaposed in parallel, using temporary aneurysm clips applied proximally and distally. CCA caliber and the length of CCA juxtaposition were measured. Side-to-side anastomosis was completed and ischemia time was recorded. Unintended complications were recorded for further analysis.

RESULTS

Anastomosis was completed successfully in all animals. The CCAs were approximated in all animals without any difficulty or undue tension. In 2 rats, death occurred prior to completion of anastomosis, which was attributed to injury to the external jugular vein during vessel exposure. Mean ischemia time was 35 min with an average of 22 sutures done to complete the anastomosis. The average CCA caliber was 1.1 ± 0.2 mm and the arteries could be juxtaposed for an average length of 10.2 ± 1.5 mm.

CONCLUSION

Full exposure of the cervical segment of the CCAs enables tension-free approximation of adequate length of the vessel for a side-to-side anastomosis. Avoiding complications during exposure helps in prevention of animal death during the ischemia period.

National trends in cerebral bypass for unruptured intracranial aneurysms: a National (Nationwide) Inpatient Sample analysis of 1998–2015

OBJECTIVE

The development and recent widespread dissemination of flow diverters may have reduced the utilization of surgical bypass procedures to treat complex or giant unruptured intracranial aneurysms (UIAs). The aim of this retrospective cohort study was to observe trends in cerebral revascularization procedures for UIAs in the United States before and after the introduction of flow diverters by using the National (Nationwide) Inpatient Sample (NIS).

METHODS

The authors extracted data from the NIS database for the years 1998–2015 using the ICD-9/10 diagnostic and procedure codes. Patients with a primary diagnosis of UIA with a concurrent bypass procedure were included in the study. Outcomes and hospital charges were analyzed.

RESULTS

A total of 216,212 patients had a primary diagnosis of UIA during the study period. The number of patients diagnosed with a UIA increased by 128% from 1998 (n = 7718) to 2015 (n = 17,600). Only 1328 of the UIA patients (0.6%) underwent cerebral bypass. The percentage of patients who underwent bypass in the flow diverter era (2010–2015) remained stable at 0.4%. Most patients who underwent bypass were white (51%), were female (62%), had a median household income in the 3rd or 4th quartiles (57%), and had private insurance (51%). The West (33%) and Midwest/North Central regions (30%) had the highest volume of bypasses, whereas the Northeast region had the lowest (15%). Compared to the period 1998–2011, bypass procedures for UIAs in 2012–2015 shifted entirely to urban teaching hospitals (100%) and to an elective basis (77%). The median hospital stay (9 vs 3 days, p < 0.0001), median hospital charges ($186,746 vs $66,361, p < 0.0001), and rate of any complication (51% vs 17%, p < 0.0001) were approximately threefold higher for the UIA patients with bypass than for those without bypass.

CONCLUSIONS

Despite a significant increase in the diagnosis of UIAs over the 17-year study period, the proportion of bypass procedures performed as part of their treatment has remained stable. Therefore, advances in endovascular aneurysm therapy do not appear to have affected the volume of bypass procedures performed in the UIA population. The authors’ findings suggest a potentially ongoing niche for bypass procedures in the contemporary treatment of UIAs.

Side-to-Side Bypass between Bilateral Distal Anterior Cerebral Arteries and Surgical Trapping of a Pseudoaneurysm from the Anterior Communicating Artery: Lessons Learnt

Background:

Treatment options for a ruptured anterior communicating artery (ACoA) pseudoaneurysm are limited. In most cases trapping of the ACoA is the best treatment option. Occasionally, bypass surgery is warranted to ensure blood flow to the contralateral anterior cerebral artery (ACA) in cases with one dominant A1. We report a case of an ACoA pseudoaneurysm presenting with delayed subarachnoid hemorrhage following surgical clipping of an unruptured ACoA aneurysm, with a review of the literature.

Case description:

A 74-year-old female had undergone surgical clipping of a 1.2-cm-sized unruptured ACoA aneurysm through the left supraorbital keyhole approach. During the operation, there had been a small tear between the aneurysm neck and the right proximal A2, and the tear point was controlled by clipping of the tear site. One month later, she was admitted again because of subarachnoid hemorrhage. Cerebral angiography showed a probable pseudoaneurysm from the previous tear site. The patient had a dominant left A1 with a right A1 aplasia. The pseudoaneurysm was treated with side-to-side bypass between the distal ACAs and subsequent trapping of the ACoA harboring a pseudoaneurysm. Both the distal ACAs were preserved; however, post-hemorrhagic neurological sequelae remained.

Conclusions:

Side-to-side bypass between distal ACAs and surgical trapping of the ACoA for the ruptured ACoA pseudoaneurysm was a good rescue option to prevent rebleeding and preserve blood supply to the contralateral ACA territory.

A3-A3 Bypass Surgery for Aneurysm: Technical Nuances

BACKGROUND

Cerebral bypass remains important for the treatment of complex cerebral aneurysms including dissecting, giant, and fusiform aneurysms not amenable to endovascular treatment or simple clip ligation. For such aneurysms involving the anterior communicating artery complex or its branches, distal anterior cerebral artery (ACA) A3-A3 side-to-side bypass represents a valuable treatment option. Distal ACA in situ anastomosis is recognized to be technically demanding mainly due to the relative depth and narrowness of the interhemispheric surgical corridor and type of anastomosis.

OBJECTIVE

To demonstrate technical nuances of A3-A3 side-to-side in situ bypass surgery through case illustrations and operative videos.

METHODS

Elements of the procedure relating to positioning, approach, and anastomosis which have evolved in the operative technique of the senior author were collated based on review of clinical case material, imaging and video recordings of ACA aneurysms treated with side-to-side in situ A3-A3 bypass procedure. Technical elements were contrasted with relevant literature.

RESULTS

Nuances relative to patient positioning, selection of craniotomy variants, adjunctive intraoperative tools and microsurgical nuances of the side-to-side bypass procedure are reviewed. Three illustrative operative video cases, along with illustrations, are provided to complement the description of the nuances.

CONCLUSION

In the light of the inherent technical difficulty, as well as the rather limited case volumes, the technical tips provided may contribute to bringing additional refinement and simplicity to the A3-A3 bypass procedure.

Coil embolization of saccular frontopolar artery aneurysm

In this case report, a distal anterior cerebral artery aneurysm was presented. While most distal anterior aneurysms occur at the bifurcation of the pericallosal and callosomarginal arteries, this particular aneurysm occurred at the frontopolar artery, a case rarely reported in published literature. The aneurysm had a recurrent subarachnoid haemorrhage due to the rupture of a saccular aneurysm and was treated through endovascular coiling.

Revascularization of the anterior cerebral artery by Y-shaped superficial temporal artery interposition graft for the treatment of a de novo aneurysm arising at the site of A3-A3 bypass: technical case report

The most frequently used option to reconstruct the anterior cerebral artery (ACA) is an ACA-ACA side-to-side anastomosis. The long-term outcome and complications of this technique are unclear. The authors report a case of a de novo aneurysm arising at the site of A3-A3 anastomosis. A 53-year-old woman underwent A3-A3 side-to-side anastomosis for the treatment of a ruptured right A2 dissecting aneurysm. At 44 months after surgery, a de novo aneurysm developed at the site of anastomosis. The aneurysm developed in the front wall of the anastomosis site, and projected to the anterosuperior direction. A computational fluid dynamics (CFD) study showed the localized region with high wall shear stress coincident with the pulsation in the front wall of the anastomosis site, where the aneurysm developed. A Y-shaped superficial temporal artery (STA) interposition graft was used successfully to reconstruct both ACAs, and then the aneurysm was trapped. To the authors' knowledge, this is the first case of a de novo aneurysm that developed at the site of an ACA-ACA side-to-side anastomosis. A CFD study showed that hemodynamic stress might be an underlying cause of the aneurysm formation. A Y-shaped STA interposition graft is a useful option to treat this aneurysm. Long-term follow-up is necessary to detect this rare complication after ACA-ACA anastomosis.

The re-anastomosis end-to-end bypass technique: a comprehensive review of the technical characteristics and surgical experience

Re-anastomosis end-to-end bypass is a straightforward subtype of intracranial-intracranial reconstruction technique that has been utilized to treat complex aneurysms and skull base tumors. This simple technique involves connecting the cut ends of an afferent and efferent artery under added tension after excising the lesion. The current study aims to provide a detailed description of the technical pitfalls, ideal anatomical sites and indications, and clinical outcomes for intracranial complex disorders. A literature search was performed using the terms "intracranial-intracranial bypass," "re-anastomosis bypass," "reconstructive bypass," "end-to-end bypass," and "end-to-end anastomosis" to identify pertinent articles. Articles involving end-to-end re-anastomosis combined with other bypass methods were excluded. Computer-tablet-drawn illustrations of this technique are provided to enhance comprehension. Eighty-six patients who met our search and inclusion criteria were identified between 1978 and the present. However, comprehensive descriptions of medical records and neuroimaging were available in only 41 cases (40 complex aneurysms and a skull base tumor). Of 40 reported cases of complex cerebral aneurysms treated by this technique, the overall rate of full recovery without complication is 87.5% (35/40). Meanwhile, all aneurysms were completely eliminated from the circulation, with 92.5% of bypasses being patent. End-to-end re-anastomosis remains a simple modality in the microsurgical bypass armamentarium. Safe and effective surgical outcomes can be achieved in select cases that rarely involve perforators or branches.

EC-IC bypass for cerebral revascularization following skull base tumor resection: Current practices and innovations

Complex skull base tumors can involve critical vessels of the head and neck. To achieve a gross total resection, vessel sacrifice may be necessary. In cases where vessel sacrifice will cause symptomatic cerebral ischemia, surgical revascularization is required. The purpose of this paper is to review cerebral revascularization for skull base tumors, the indications for these procedures, outcomes, advances, and future directions.

Superficial temporal artery-middle cerebral artery bypass for the treatment of complex middle cerebral artery aneurysms

Objectives:

Direct microsurgical clipping for complex middle cerebral artery (MCA) aneurysms may require a long ischemic time. Sacrifice of the parent artery with trapping or endovascular coiling also may lead to ischemic stroke. We described our institutional experience with the treatment of complex MCA aneurysms using extracranial-intracranial (EC-IC) (superficial temporal artery [STA]-MCA) bypass.

Materials and Methods:

We retrospectively reviewed patients who had treatment of IC aneurysms with the assistance of STA-MCA bypass from July 2002 to December 2016. Six patients with complex MCA aneurysms were identified, and we reviewed their clinical characteristics.

Results:

There were three men and three women with age ranging from 27 to 59 (mean 49) years old. Image studies showed subarachnoid hemorrhage in three cases. All patients underwent STA-MCA anastomosis, and the follow-up period ranged from 2 to 116 months (mean 51.5 months). Two of the six MCA aneurysms were fusiform, two aneurysms had bizarre configurations, one was a dissecting saccular aneurysm, and one had a blister configuration. Three patients received direct vessel trapping, two patients received aneurysm clipping, and one received aneurysm coiling. The postoperative bypass patency rate was 100%. The modified Rankin scale showed good outcomes in the six patients.

Conclusions:

EC-IC bypass plays an important role as a salvage procedure in the treatment of complex MCA aneurysms which have a fusiform, bizarre, or blister configuration.

Safety and Efficacy of Flow Diverter Treatment for Aneurysm in Small Cerebral Vessels: A Systematic Review and Meta-Analysis

PURPOSE

To clarify the safety and efficacy of flow diverter (FD) treatment for aneurysm in small cerebral vessels, we conducted a systematic review of the literature analyzing perioperative and long-term clinical and angiographic outcomes.

METHODS

A comprehensive review of the up-to-date literature for studies with ≥10 patients related to FD treatment of small vessel aneurysms published was performed. Random-effects meta-analysis was used to pool the following outcomes: complete occlusion, technical procedural success, perioperative mortality, perioperative stroke, procedure-related morbidity and mortality, all complications, long-term mortality, and overall good outcome.

RESULTS

We included 26 noncomparative studies with 572 target aneurysms. The technical procedural success rate was 96% (95% confidence interval [CI] 0.93-1.00). At final follow-up, the complete occlusion rate was 70% (95% CI 0.64-0.76). The all-cause morbidity rate was 20% (95% CI 0.14-0.25). Procedure-related morbidity and mortality rates were 9% (95% CI 0.07-0.12) and 4% (95% CI 0.00-0.08), respectively. Overall long-term good outcome rate was 96% (95% CI 0.93-0.99). In the 3 subgroup analyses, complete occlusion rate of saccular aneurysms was lower than that of nonsaccular aneurysms (55% vs. 73%, respectively; odds ratio 0.40, 95% CI 0.17-0.98, P = 0.04). The procedure-related morbidity rate and the good outcome rate were not significantly different in this subgroup. In the other 2 subgroups in which we compared anterior circulation aneurysms with posterior circulation aneurysms and single FD strategy with overlapped FD strategy, the rates were also not significantly different.

CONCLUSIONS

Our meta-analysis demonstrated that FD treatment of small vessel aneurysms is technically feasible and effective with a high rate of complete occlusion. Although the comorbidities of patients cannot be neglected, the FD approach was associated with an acceptable rate of procedure-related morbidity and a satisfactory rate of overall good outcome.

STA-ACA bypass using the ipsilateral free STA graft as an interposition graft and A3-A3 anastomosis for treatment of bilateral ACA steno-occlusive ischemia

BACKGROUND

Anterior cerebral artery (ACA)-related ischemia is a rare entity in patients with atherosclerosis. Some surgical treatments are reported to date.

METHOD

We present the modification of intracranial-intracranial and intracranial-extracranial bypasses for symptomatic bilateral ACA steno-occlusive disease. The A3-A3 bypass followed by the superficial temporal artery-ACA bypass using the ipsilateral free superficial temporal artery graft is useful without harvesting of the radial artery.

CONCLUSION

Bilateral ACA steno-occlusive induced ischemia can be treated with tailored bypass procedures.

Endovascular treatment of complex intracranial aneurysms

PURPOSE

Complex intracranial aneurysms (CIA) are heterogenous group of intracranial vascular malformations. Due to its giant size, difficult location, broad neck, branches arising from the aneurysm, wall structure, calcification, presence of intraluminal thrombus or previous treatments it requires more careful approach. The aim of this study was to evaluate endovascular treatment results of CIA in our Department.

MATERIAL AND METHODS

In order to differentiate CIA from all the aneurysms, treated endovascularly in years 2008-2014, authors proposed their own qualification criteria. Additionally, subgroup of patients with CIA with simultaneous subarachnoid haemorrhage (SAH) was divided. Clinical outcomes of patients were assessed with Glasgow Outcome Scale (GOS), while radiological outcomes were assessed with Montreal Scale. Aneurysm localization, incidence of aborted procedures, intraoperative complications were also evaluated.

RESULTS

Internal carotid artery was the most common localization in both CIA and non-complex (nCIA) groups. Incidence of aborted procedures was significantly higher in CIA group than in nCIA (25% vs. 7%; p < 0.01). CIA group had worse Montreal scores then nCIA group (1.90 vs. 1.49; p < 0.01). Clinical outcome in GOS scale in patients with SAH and CIA was significantly worse than in SAH and nCIA (2.86 vs. 4.06; p = 0.04).

CONCLUSIONS

To conclude, proposed criteria of CIA should be taken into consideration during diagnosis and qualification to invasive treatment. Classifying aneurysm as CIA is related to greater possibility of aborting endovascular procedure due to technical difficulties.

Contemporary endovascular and open aneurysm treatment in the era of flow diversion

Clinical outcomes have improved considerably over the last decade for patients with ruptured and unruptured aneurysms. Modern endovascular techniques, such as flow diversion, are associated with high aneurysm occlusion rates and have become a popular treatment modality for many types of aneurysms. However, the safety and effectiveness of flow diversion has not yet been established in trials comparing it with traditional aneurysm treatments. Moreover, there are some types of aneurysms that may not be appropriate for endovascular coiling, such as wide-necked aneurysms located at branch points of major vessels, large saccular aneurysms with multiple efferent arteries, dolichoectatic aneurysms, large aneurysms with mass effect, when there are technical complications with endovascular treatment, when patients cannot tolerate or have contraindications to antiplatelet therapy or in the setting of a subarachnoid haemorrhage. For these cases, open cerebrovascular surgery remains important. This review provides a discussion on the current trends and evidence for both flow diversion and open cerebrovascular surgery for complex aneurysms that may not be suitable for coiling. We emphasise a continued important role for surgical treatment in certain situations.