Periprocedural management of patients presenting for neurointerventional procedures using flow diverters for complex intracranial aneurysms: An anesthetist's perspective - A narrative review.

Complex intracranial aneurysms pose significant challenges in the realm of neurointervention, necessitating meticulous planning and execution. This article highlights the crucial roles played by anesthetists in these procedures, including patient assessment, anesthesia planning, and continuous monitoring and maintaining hemodynamic stability, which are pivotal in optimizing patient safety. Understanding these complex procedures and their complications will aid the anesthetist in delivering optimal care and in foreseeing and managing the potential associated complications. The anesthetist's responsibility extends beyond the procedure itself to postprocedure care, ensuring a smooth transition to the recovery phase. Successful periprocedural anesthetic management in flow diverter interventions for complex intracranial aneurysms hinges on carefully orchestrating these elements. Moreover, effective communication and collaboration with the interventional neuroradiologist and the procedural team are emphasized, as they contribute significantly to procedural success. This article underscores the essential requirement for a multidisciplinary team approach when managing patients undergoing neurointerventions. In this collaborative framework, the expertise of the anesthetist harmoniously complements the skills and knowledge of other team members, contributing to the overall success and safety of these procedures. By providing a high level of care throughout the periprocedural period, anesthetists play a pivotal role in enhancing patient outcomes and minimizing the risks associated with these intricate procedures. In conclusion, the periprocedural anesthetic management of neurointervention using flow diverters for complex intracranial aneurysms is a multifaceted process that requires expertise, communication, and collaboration.

Optimizing the Approach to STA-MCA Bypass Surgery and Reducing Wound Complications.

BACKGROUND AND OBJECTIVES: The treatment of complex intracranial aneurysms with bypass surgery using 2 branches of the superficial temporal artery (STA) proves to be an effective surgical option. However, the harvest of these 2 STA branches, combined with a pterional craniotomy, carries the potential risk of delayed wound healing of the skin flap. This study undertook a retrospective analysis to examine and identify the factors associated with this delayed wound healing. METHODS: A total of 56 consecutive cases, including both ruptured and unruptured complex intracranial aneurysms, that underwent bypass surgery with 2 branches of the STA, were analyzed retrospectively. RESULTS: Major delayed wound healing was observed in 6 (10.7%) cases. Univariate analysis demonstrated significant associations with the following factors: rupture (P = 0.023), presence of diabetes mellitus (P = 0.028), large craniotomy size (P = 0.012), and the type of skin incision (P ≤ 0.001). Age (P = 0.283), sex (P = 0.558), body mass index (P = 0.221), and other blood test parameters did not demonstrate any statistical significance. Similarly, the presence of a dominant frontal branch (P = 0.515) or a low-positioned frontal branch (P = 0.622) did not reveal statistically significant results. CONCLUSIONS: In the treatment of complex intracranial aneurysms, where harvesting of the 2 STA branches is involved with a pterional craniotomy, producing a smaller skin flap (L- or T-shaped incision) is effective in minimizing the risk of delayed wound healing. The process of harvesting the STA and closing the wound demands meticulous care, taking into consideration the normal anatomical structures and the subdermal vascular plexus of the scalp.

Role of multimodal monitoring in the management of patients undergoing complex intracranial bypass procedures - A case series and literature review.

Patients undergoing complex intracranial neurovascular procedures continue to have a high mortality rate. Individualised goal-directed cerebral resuscitation employing multimodality neuromonitoring may impact these patients' treatment and prognosis. Advanced monitoring methods aid in the early identification of secondary brain insults and serve as endpoints for goal-directed therapy in the perioperative period. Unfortunately, there is a paucity of literature exploring the impact of multimodality monitoring and its outcome in these patients. We aim to present this case series wherein the patients had a favourable outcome post-intracranial complex bypass procedure, owing to goal-directed management guided by multimodality monitoring in the perioperative period.

Complex Intracranial Aneurysms.

Complex intracranial aneurysms remain challenging to treat using standard microsurgical or endovascular techniques. These aneurysms often require a combination of deconstructive and reconstructive procedures, such as parent artery occlusion, flow alteration, and blind-alley formation with or without bypass surgery, for effective and enduring therapeutic effects. It is important to determine the type of bypass based on the site of occlusion of the patent artery, anatomical features of the distal vessels, and expected adequate blood flow. In this chapter, we describe the "Standards," "Advances," and "Controversies" in the context of a microsurgical treatment strategy for complex intracranial aneurysms. "Standards" include a combination of frequent and commonly used procedures that have been gathering a certain consensus on their effectiveness. "Advances" include infrequent, demanding, and/or uncertain surgical procedures that are currently under debate. Finally, "Controversies" discuss a number of unsolved issues.

Anterior Cerebral Artery Bypass for Complex Aneurysms: Advances in Intracranial-Intracranial Bypass Techniques.

BACKGROUND: Anterior cerebral artery (ACA) bypasses for complex aneurysms are infrequently performed, yet previous experience demonstrates the importance of intracranial-intracranial bypasses. Here we describe technical advances in intracranial-intracranial bypass techniques and their clinical results. METHODS: Twenty-three patients with complex aneurysms requiring ACA bypasses were retrospectively studied. Ten patients were treated in period 1 (1997-2013) and 13 in period 2 (2014-2018). RESULTS: There were 3 precommunicating, 8 communicating, and 8 postcommunicating ACA aneurysms, plus 4 middle cerebral artery aneurysms. ACA in situ bypass was the most commonly performed (9 patients; 39%). The classic left A3 ACA-right A3 ACA in situ bypass was performed in 5 patients, but 3 new in situ variations emerged in period 2: left pericallosal artery (PcaA)-right PcaA (n = 1), left callosomarginal artery (CmaA)-right CmaA (n = 2), and left CmaA-right A3 ACA (n = 1). The sole reimplantation in period 1 was the ipsilateral and vertical PcaA-CmaA reimplantation, whereas reimplantations in period 2 were contralateral and horizontal (left PcaA-right PcaA and right A3 ACA-left anterior internal frontal artery). The A1 ACA was used as a donor only in period 2 in 4 patients with middle cerebral artery bifurcation aneurysms. Bypass patency was 91%, and 21 patients (91%) improved or remained at neurologic baseline (mean [standard deviation] follow-up duration, 26 [8.2] months). CONCLUSIONS: ACA bypass techniques continue to evolve with the addition of several variations. These variations push bypass techniques beyond the standard constructs and add important alternatives to our bypass arsenal.

"Reverse Picket Fence" Technique for Clipping of a Large, Anterior Communicating Artery Aneurysm: 2-Dimensional Operative Video.

The "picket fence" technique is a clipping technique used for large, wide-neck complex aneurysms not suitable for conventional clipping.1 With this technique, simple or fenestrated straight clips are stacked side-by-side perpendicular to the neck rather than the conventional parallel placement. In complex aneurysms projecting away from the surgeon, the picket fence technique is impossible. Instead, fenestrated clips are applied in a reverse direction from neck-to-dome, using the blade heels to close the neck. This fenestration tube transmits the bifurcation. This video demonstrates a "reverse picket fence" clipping technique of an incidental, large anterior communicating artery (ACoA) aneurysm in a 52-yr-old woman. Bilaterally adherent A2-anterior cerebral artery (ACA) segments led to abortion of a prior clipping attempt at an outside hospital. After obtaining patient consent, a modified orbitozygomatic craniotomy was performed with gyrus rectus removal. Temporary clips were applied to A1-ACA for freeing the adherent A2-ACA segments from the dome. The aneurysm was clipped using a "reverse picket fence" technique transmitting the A1-A2-A2 bifurcation through the fenestration tube. Bilateral recurrent artery of Heubner was preserved. Indocyanine angiography demonstrated parent vessel patency with complete aneurysm exclusion. Postoperatively, the patient experienced short-term memory loss, which resolved over 6 mo with cognitive rehabilitation. The "reverse picket fence" technique can be considered for large aneurysms directed away from the surgeon, obviating the need for difficult dissection of adherent efferent arteries from aneurysmal sac. Adjusting the heel position of each fenestrated clip in this construct allows the patency of hidden perforators behind the aneurysm to be maintained. Video © Barrow Neurological Institute. Used with permission.

Assessment of ischemic risk following intracranial-to-intracranial and extracranial-to-intracranial bypass for complex aneurysms using intraoperative Indocyanine Green-based flow analysis.

Cerebral bypass is often needed for complex aneurysms requiring vessel sacrifice, yet intraoperative predictors of ischemic risk in bypass-dependent territories are limited. Indocyanine Green (ICG)-based flow analyses (ICG-BFAs; Flow 800, Carl Zeiss, Oberkochen, Germany) semi-quantitatively assess cortical perfusion, and in this work we determine the efficacy of ICG-BFA for assessing post-operative ischemic risk during cerebral bypass surgery for complex aneurysms. Retrospective clinical and pre/post-bypass intra-operative ICG-BFA data (delay and blood flow index [BFI]) on ten patients undergoing cerebral bypass for complex cerebral aneurysms requiring vessel sacrifice were collected from a single-institution prospective database and analyzed via non-parametric testing and logistic regression. Mean age was 55.9 ±â€¯14.8 years. Pre/post-bypass delay (median 35.6 [5.1-51.3] vs. 26.0 [17.1-59.9]; p = 0.2) and BFI (median 56.1 [8.1-120.4] vs. 32.2 [3.0-147.4]; p = 0.2) did not significantly differ. Two patients (20%) developed post-operative ischemia in bypass dependent territories. Delay ratio did not differ between patients with and without post-operative ischemia (median 1.15 [0.67-1.64] vs. 0.83 [0.36-3.56]; p = 0.6), nor predict stroke risk (odds ratio = 1.1, p = 0.9). Conversely, BFI ratio was significantly lower for patients experiencing post-operative ischemia than those without ischemia (median 0.11 [0.06-0.17] vs. 0.99 [0.28-1.42]; p = 0.03). A BFI ratio <0.21 predicted the occurrence of post-operative ischemia (odds ratio = 0.02, p = 0.05). These data suggest that intraoperative ICG-BFA may help assess post-operative ischemic risk during cerebral bypass surgery for complex aneurysms requiring vessel sacrifice.

Intracranial-Intracranial Bypass with a Graft Vessel: A Comprehensive Review of Technical Characteristics and Surgical Experience.

OBJECTIVE: Intracranial-intracranial (IC-IC) bypass with a graft vessel (IBGV) is a straightforward arterial reconstruction technique used for the treatment of complex aneurysms and skull base tumors. We have described the technical characteristics and summarized the clinical results of IBGV in complex cerebrovascular disorders. METHODS: We performed a search of the PubMed and Google Scholar online databases. The terms "intracranial-intracranial bypass," "jump graft bypass," "interposition graft bypass," "radial artery graft bypass," "saphenous vein graft bypass," and "superficial temporal artery graft bypass" were searched. Studies involving IBGV combined with other bypass methods were excluded. Illustrations of the technique have been provided to enhance comprehension. RESULTS: We identified 59 cases involving 6 types of graft vessels were identified from 1978 to July 2018. The IBGV technique was divided into the following 4 subtypes: type IA, in situ interposition graft bypass; type IB, Y-shaped double-barrel interposition graft bypass; type IIA, long jump graft bypass; and type IIB, Y-shaped double-barrel jump graft bypass. Grafts from the radial (44.1%; 26 of 59) and superficial temporal (39.3%; 22 of 59) arteries were used most frequently, and the middle cerebral artery territory was the most commonly involved region for IBGV. Of the cases with the specified postoperative characteristics, the graft patency and overall uneventful rates were 96.3% (52 of 54) and 82.2% (37 of 45), respectively. A higher patency rate (100% vs. 90.5%) and a lower complication rate (<20% vs. 60%) were observed with the type II group with an arterial graft. CONCLUSIONS: The IBGV method is a technically feasible option for vascular disease or complex cerebral tumors and should be considered by neurosurgeons. Long jump bypass with arterial grafts should be preferred when IC-IC bypass has been considered owing to the high rates of graft patency and favorable clinical outcomes.

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.

The In Situ Side-To-Side Bypass Technique: A Comprehensive Review of the Technical Characteristics, Current Anastomosis Approaches, and Surgical Experience.

OBJECTIVE: In situ side-to-side (STS) revascularization is an intracranial-intracranial bypass technique that is increasingly used to treat complex aneurysms and cerebral ischemia. This sophisticated technique involves connecting 2 proximal parallel vessels to create an artificial conduit for blood flow. This study aims to provide a detailed description of the configuration of the STS bypass technique and extensive information regarding its technical characteristics, current anastomosis approaches, and surgical significance. METHODS: A literature search was performed using the PubMed, Medline, ScienceDirect, Embase, Wiley Online Library, Cambridge Journals, SAGE Journals, Oxford Journals, Research Gate, and Google Scholar databases. The terms "intracranial-intracranial bypass," "in situ bypass," "communicating bypass," and "STS anastomosis" were searched to identify pertinent articles. Articles involving in situ STS anastomosis combined with other bypass methods were excluded. Computer tablet-drawn illustrations of this technique are provided to enhance comprehension. RESULTS: In total, 70 articles that met our search and inclusion criteria were identified. Overall, the radiographic and clinical outcomes of 132 (125 aneurysms and 7 cerebral ischemias) patients who underwent in situ STS revascularization were analyzed. CONCLUSIONS: Intracranial-intracranial bypass in the STS fashion can be a safe and effective strategy for the management of complex intracranial aneurysms and cerebral ischemia and is particularly attractive in rescue, anticipated, and troubleshooting cases. Despite its extreme rarity, a de novo aneurysm may be observed after STS anastomosis; thus, long-term follow-up is mandatory. Vascular neurosurgeons should consider including this procedure in their treatment armamentarium.

The effectiveness of the waffle-cone technique in treating complex intracranial aneurysms.

We report 13 consecutive cases of complex intracranial aneurysms treated by the waffle-cone technique and the midterm angiographic results and discuss the effectiveness and safety of this technique. We performed a retrospective review to evaluating the angiographic results and clinical effectiveness of 15 cases in which waffle-cone stenting for treating broad-necked complex intracranial aneurysms at our institution up to July 2008. Among these 15 patients, we enrolled 13 patients who had undergone at least one follow-up angiography. We collected patient data including age, sex, ruptured state, aneurysm size, neck size, complications, initial Hunt and Hess (HH) grade, modified Rankin Score (mRS) at the last angiographic follow-up, and initial and follow- up angiographic results.The mean size of the aneurysm was 10.6 mm (range, 4.0 to 20.4 mm) and the mean size of the aneurysm neck was 5.7 mm (range, 2.7 to 9.2 mm). The mean angiographic follow-up time was 13.6 months (range, six to 30 months). There were no procedure-related complications. However, there were two delayed complications. One complication was delayed focal embolic infarct and the other complication was delayed rebleeding. Angiographic improvement was achieved in two cases (15.4%), stable occlusion was achieved in seven cases (53.8%), and recanalization or compaction that needed retreatment occurred in four cases (30.8%). We think that the waffle-cone technique is an effective alternative in selected aneurysms unable to be "Y" stented or surgically clipped.

The efficacy of bypass surgery using a short interposition graft for the treatment of intracranial complex aneurysm.

OBJECTIVE: To evaluate the efficacy of a short interposition graft using saphenous vein or radial artery to connect the proximal superficial temporal artery and the M2 segments of the middle cerebral artery for the treatment of complex intracranial aneurysm. METHODS: From March 2007 to February 2012, short interposition graft bypass operations were performed in 13 patients with complex intracranial aneurysms. There were 6 ruptured aneurysms, including blood blister-like aneurysms in 3 patients, giant aneurysms in 2 patients, and fusiform dissecting aneurysm in 1 patient. Among 7 patients with unruptured aneurysms, there were 5 giant aneurysms and 2 large fusiform aneurysms in the M2 segment. RESULTS: Parent artery occlusion with endovascular coiling (3 patients) or trapping by direct clipping (10 patients) was used to treat complex cerebral aneurysms. Complete occlusion of the aneurysm was demonstrated in 11 patients (85%); the other 2 patients did not demonstrate occlusion immediately postoperatively. Except for 2 patients who presented with poor-grade subarachnoid hemorrhage, patients (n = 11; 85%) demonstrated good scores on the Glasgow Outcome Scale. No new neurologic deficits developed in relation to insufficient blood flow through the bypass graft. In all 13 patients, graft patency was good at long-term follow-up (overall mean follow-up, 28.2 months). CONCLUSIONS: Superficial temporal artery-middle cerebral artery bypass surgery using a short interposition graft for intracranial complex aneurysms seems to be safe and efficient hemodynamically after occlusion of the parent artery. It could be regarded as a good alternative to high-flow bypass surgery.