Angiographic and Clinical Outcomes of Various Techniques of Intracranial-to-Intracranial Bypass for Complex Cases with a Review of Pertinent Literature and Illustrated Cases

BACKGROUND

We sought to determine the utility of intracranial-to-intracranial bypass (IIB) surgery and the available bypass options for complex cases.

METHODS

A total of 18 IIB cases were included. Each case was classified as IIB with or without an interposition graft. The clinical and angiographic status were evaluated pre- and postoperatively and at the last follow-up. Angiographic images were analyzed and reconstructed schematically. Postoperative angiography was used to measure the bypass patency and the presence of postoperative cerebral infarction. The recipient artery occlusion time for each bypass was measured.

RESULTS

Of the 18 patients, 14 had presented with a complex intracranial aneurysm (IA), 1 with vertebrobasilar dolichoectasia, and 3 with intracranial arterial steno-occlusive disease. Ten patients had an incidentally discovered IA. Seven patients had presented with neurological deficits due to ischemia or aneurysmal mass effects. Of the 18 cases, 10 were IIBs with an interposition graft, including 4 cases of superficial temporal artery and 6 of radial artery graft bypass, and 8 were IIBs with a noninterposition graft, including 3 cases of in situ bypass, 1 case of reanastomosis, and 4 cases of reimplantation. The pre- and postoperative modified Rankin scale score did not change or improve, and all the bypasses were patent. No patient had died during the mean follow-up period of 50.0 months. The mean occlusion time of the recipient artery was 59.5 minutes. A total of 8 patients experienced postoperative cerebral infarction but all had almost recovered at discharge.

CONCLUSIONS

With proper selection of the IIB type, IIB can be a suitable treatment option for some patients with complex IAs and intracranial arterial steno-occlusive disease when extracranial-to-intracranial bypass is not feasible.

Arterial Bypass in the Treatment of Complex Middle Cerebral Artery Aneurysms: Lessons Learned from Forty Patients

OBJECTIVE

Complex middle cerebral artery (MCA) aneurysms incorporating parent or branching vessels are often not amenable to standard microsurgical clipping or endovascular embolization treatments. We aim to discuss the treatment of such aneurysms via a combination of surgical revascularization and aneurysm exclusion based on our institutional experience.

METHODS

Thirty-four patients with complex MCA aneurysms were treated with bypass and aneurysm occlusion, 5 with surgical clipping or wrapping only, and 1 with aneurysm excision and primary reanastomosis. Bypasses included superficial temporal artery (STA)-MCA, double-barrel STA-MCA, occipital artery-MCA, and external carotid artery-MCA. After bypass, aneurysms were treated by surgical clipping, Hunterian ligation, trapping, or coil embolization.

RESULTS

The average age at diagnosis was 46 years. Of the aneurysms, 67% were large and most involved the MCA bifurcation. Most bypasses performed were STA-MCA bypasses, 12 of which were double-barrel. There were 2 wound-healing complications. All but 2 of the aneurysms treated showed complete occlusion at the last follow-up. There were 3 hemorrhagic complications, 3 graft thromboses, and 4 ischemic insults. The mean follow-up was 73 months. Of patients, 83% reported stable or improved symptoms from presentation and 73% reported a functional status (Glasgow Outcome Scale score 4 or 5) at the latest available follow-up.

CONCLUSIONS

Cerebral revascularization by bypass followed by aneurysm or parent artery occlusion is an effective treatment option for complex MCA aneurysms that cannot be safely treated by standard microsurgical or endovascular techniques. Double-barrel bypass consisting of 2 STA branches to 2 MCA branches yields adequate flow replacement in most cases.

Extracranial-intracranial bypass surgery for intracranial aneurysm of the anterior cerebral circulation: A systematic review and meta-analysis

Background

The safety of extracranial–intracranial (EC–IC) bypass in the management of anterior circulation intracranial aneurysms (IAs) remains to be determined. This systematic review aims to summarize the existing evidence and provide guidance for the precise management of IAs.

Data source

We constructed search strategies and comprehensively searched Pubmed, Medline, Embase, Web of science, and Cochrane library.

Methods

This systematic review was actualized according to the PRISMA statement. We evaluated study quality using the methodological index for non-randomized study (MINORS). Effect sizes were pooled using a random-effects model. Heterogeneity between studies was assessed using the I2 test. Publication bias was assessed using the Egger's test. The registration number for this systematic review is CRD42023396730.

Result

This systematic review included a total of 21 articles, involving 915 patients. Postoperative bypass patency rate was 99% (95% CI 0.98–1.00); short-term follow-up was 98% (95% CI 0.94–1.00); long-term follow-up was 95% (95% CI 0.93–0.97). The long-term follow-up occlusion rate of saphenous vein was higher than that of radial artery (OR 6.10 95% CI 1.04–35.59). Short-term surgery-related mortality was 0.3% (95% CI 0.000–0.012); long-term follow-up was 0.4% (95% CI 0.000–0.013); The proportion of patients with a score of 0–2 on the modified Rankin Scale (mRS) during long-term follow-up was 92% (95% CI 0.86–0.98). The incidence rates of long-term follow-up complications were: ischemic 3% (95% CI 0.01–0.06); hemorrhagic 1% (95% CI 0.00–0.03); neurological deficit 1% (95% CI 0.00–0.03); other 3% (95% CI 0.01–0.06).

Limitation

Most of the included studies were retrospective studies. Studies reporting preoperative status were not sufficient to demonstrate postoperative improvement. Lack of sufficient subgroup information such as aneurysm rupture status.

Conclusion

EC–IC therapy for anterior circulation IAs has a high safety profile. Higher level of evidence is still needed to support clinical decision.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023396730, identifier: CRD42023396730.

Evolution of Intracranial-Intracranial Bypass Surgery: A Bibliometric Analysis

OBJECTIVE

Modern cerebrovascular bypass surgery uses either extracranial-intracranial (EC-IC) or intracranial-intracranial (IC-IC) approaches. Compared with EC-IC bypasses, IC-IC bypasses allow neurosurgeons to safely address tumors, aneurysms, and other lesions using shorter grafts that are well matched to the size of recipient vessels. Fewer than 100 articles have been published on IC-IC bypasses compared with more than 1000 on EC-IC bypasses. This study examined the increase of interest and innovation in IC-IC bypass.

METHODS

PubMed and Web of Science were searched using keywords specific to IC-IC bypass, yielding 717 articles supplemented with 36 reports from other databases and gray literature. The articles were reviewed, and 98 articles were selected for further evaluation. Final articles were categorized as innovations or retrospective studies. Publication metrics were passed through an analytic program to assess statistical measures of growth.

RESULTS

The number of publications describing innovations (n = 52) and retrospective studies (n = 46) in IC-IC surgical techniques increased exponentially (R2 = 0.983 and R2 = 0.993, respectively), with both interest and research in the field increasing. The rate of publications in each group also increased. In recent years, increasing numbers of global institutions have researched and published on IC-IC bypasses.

CONCLUSIONS

As more work is undertaken on IC-IC bypasses, it is critical for knowledge to be shared through research, collaboration, publication, and early teaching within residency training programs. This field has increased exponentially in the past 2 decades and has yet to reach an inflection point, indicating possible additional interest and growth over time.

Multiple overlapping stent-assisted coiling improves efficacy and safety of treatment for complex intracranial aneurysms: a randomized trial

BACKGROUND

Intracranial aneurysm rupture is the main cause of subarachnoid hemorrhage, leading to high disability and mortality. This study aimed to evaluate the clinical treatment effects of multiple overlapping stent-assisted coiling for complex intracranial aneurysms.

METHODS

We conducted a randomized, controlled, single-blinded clinical trial among 168 patients diagnosed with complex intracranial aneurysms. Treatment allocation to either single stent (SS) group or multiple stent (MS) group was randomized at 1:1 ratio using a Web-based platform. The O'Kelly-Marotta (OKM) grading scale was used to evaluate the degree of aneurysm occlusion after operation and during follow-up. Good aneurysm occlusion was defined as OKM grade C-D. The modified Rankin Scale (mRS) was used to evaluate the neurological status and the clinical outcome of patients.

RESULTS

Efficacy comparative analysis demonstrated that major recurrence of aneurysms was significantly reduced in the MS group (P = 0.012). In addition, the MS group displayed significantly reduced number of patients with mRS between 3 and 6 (P = 0.007) and increased number of patients with mRS between 0 and 1 (P = 0.034). Furthermore, the MS group showed increased percentage of patients with OKM grade C-D (P = 0.041). Compared with the SS group, the MS group exhibited decreased mortality (P = 0.037) and morbidity (P = 0.035).

CONCLUSIONS

Multiple overlapping stent-assisted coiling significantly improved the clinical treatment effects and provided a new method for complex intracranial aneurysms.

Rescue Strategy for Troublesome Situations Related to Recipient and Donor Arteries During Low-Flow Bypass Surgery

OBJECTIVE

Although technically demanding, bypass surgery is a vital part of the neurosurgical armamentarium. The aim of this article was to present representative troublesome cases related to the manipulation of donor arteries (DAs) and recipient arteries during low-flow extracranial-intracranial bypass.

METHODS

In the past 5 years, 507 low-flow bypass surgeries were performed in patients with cerebral aneurysms, moyamoya disease, and intracranial atherosclerotic stenosis. Frustrating perioperative situations were retrospectively reviewed, and 6 representative cases were described.

RESULTS

Case 1 involved repeat microanastomosis owing to occlusion of the anastomotic segment by thrombus formation. Case 2 involved repair of the DA injured by thermal energy. Case 3 involved direct repair of the DA damaged by a sharp knife. Case 4 involved repeat microanastomosis owing to avulsion of the anastomotic segment. Case 5 involved lengthening of the short DA with a nearby interposition graft. Case 6 involved use of retrograde flow via the distal segment of the DA secondary to the injury of the proximal segment of the DA. In all patients, rescue procedures were successful, and bypass flow was patent with no relevant complications.

CONCLUSIONS

The intraoperative accidents reported here were frustrating; however, all patients were safely rescued without significant sequelae. It is hoped that our experiences will help young neurosurgeons handle troublesome situations.

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.

Determination of Aneurysm Volume Critical for Stability After Coil Embolization: A Retrospective Study of 3530 Aneurysms

BACKGROUND

Recurrence is one of the concerns even after successful endovascular treatment of intracranial aneurysms. We sought to determine the critical aneurysm volume and risk factors related to aneurysmal stability in patients undergoing coil embolization of intracranial aneurysms.

METHODS

Aneurysm volume and follow-up imaging data were retrieved in 3042 patients with 3530 aneurysms who were treated with endovascular coil embolization from January 2006 to October 2016. We analyzed the anatomic outcome in relation to aneurysm volume and determined the critical aneurysm volume favoring coil embolization.

RESULTS

Recanalization rates were 2.8%, 6.3%, 19.4%, and 67.4% in each group with aneurysm volume of <10, 10-100, 100-1000, and >1000 mm³, respectively. When we investigated the 100-1000 mm³ group, the recanalization rate remarkably increased at 500 mm³ (16.4% vs. 57.5%, P < 0.0001; odds ratio [OR], 6.968; 95% confidence interval [CI], 3.562-13.631). In the entire cohort, recanalization rates were significantly different between aneurysm volume of <500 and >500 mm³ (7.2% vs. 62.9%, respectively; P < 0.0001; OR, 21.848; 95% CI, 13.944-34.235). In aneurysm volumes of >500 mm³, the location was a significant prognostic factor for long-term stability (posterior circulation vs. anterior circulation; OR, 4.737; 95% CI, 1.275-17.602; P = 0.020).

CONCLUSIONS

In our series of cerebral aneurysms treated with coil embolization, 500 mm³ was found to be the critical volume determining stability after coil embolization. Large volume aneurysms in the posterior circulation were especially prone to recanalization after coiling.

Bypass Surgery for Complex Internal Carotid Artery Aneurysms: 39 Consecutive Patients

OBJECTIVE

Bypass surgery is a special technique used to treat complex internal carotid artery (ICA) aneurysms. The aim of this retrospective study is to provide a comprehensive description of treatment and outcome of complex ICA aneurysms at different ICA segments (cavernous, supraclinoid, ICA bifurcation) treated with bypass procedures.

METHODS

We identified 39 consecutive patients with 41 complex ICA aneurysms that were treated with 44 bypass procedures between 1998 and 2016. We divided the aneurysms into 3 anatomic subgroups to review our treatment strategy. All the imaging studies and medical records were reviewed for relevant information.

RESULTS

The aneurysm occlusion (n = 34, 83%) or flow modification (n = 5, 12%) was achieved in 39 aneurysms (95%). The long-term bypass patency rate was 68% (n = 30). Minor postoperative ischemia or hemorrhage was commonly seen (n = 20, 51%), but large-scale strokes were rare (n = 1, 3%). Preoperative dysfunction of extraocular muscles (cranial nerves III, IV, and VI) showed low-to-moderate improvement rates (20%-50%). Preoperative vision disturbance (cranial nerve II) improved seldom (22%). At the latest follow-up (mean; 51 months) 29 patients (74%) were independent (modified Rankin Scale ≤2).

CONCLUSIONS

Bypass surgery for complex ICA aneurysms is a feasible treatment method with an acceptable risk profile. Patients should be informed of the uncertainty related to improvement of pretreatment cranial nerve dysfunctions.

Surgical Treatment of Recurrent Previously Coiled and/or Stent-Coiled Intracerebral Aneurysms: A Single-Center Experience in a Series of 75 Patients

BACKGROUND

Endovascular treated cerebral aneurysms have a greater recurrence rate compared with microsurgical clip ligation. Despite recent endovascular advances, microsurgical clip ligation might be the treatment of choice for certain previously endovascular treated recurrent aneurysms. We report on our single-center experience with 76 previously coiled and/or stent-coiled aneurysms.

OBJECTIVE

To analyze the surgical and radiologic outcome after clipping of previous endovascular treated recurrent cerebral aneurysms.

METHODS

Patients were retrospectively identified. Demographic data, aneurysm size, location, perioperative coil extraction, occlusion rate, and complication rate were recorded. Patients were divided into a previously coiled-only group (COG) and a previously stent-assisted coiled group (SAC).

RESULTS

Seventy-five patients with 76 aneurysms were included. Sixty-nine patients were included in the COG, 7 patients in the SAC group. Complete or acceptable near-complete occlusion was obtained in 95% of patients in the COG and 57% in the SAC group. Two patients in the COG (2.9%) died postoperatively of a major stroke. One patient died of rehemorrhage after wrapping of an aneurysm. Minor complications occurred in 8.7%. In the SAC group, the mortality was 0%, with 1 major stroke (14.2%), 1 minor stroke (14.2%), and 1 cranial nerve palsy (14.2%). Intraoperative coil extraction and previous stent-assisted coiling were significant predictors of complication rate (P = 0.025 and P = 0.0036 respectively). Previous stent-assisted coiling was a significant predictor of incomplete occlusion (P = 0.036).

CONCLUSIONS

Microsurgical clipping of previously endovascular treated recurrent aneurysms is an effective treatment with high obliteration rates. Previously stent-assisted coiling and intraoperative coil extraction are predictors of worse outcome and incomplete occlusion.

The History and Evolution of Internal Maxillary Artery Bypass

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