Bypass Patency Research Articles

Bypass Patency and Amputation-Free Survival after Popliteal Aneurysm Exclusion Significantly Depends on Patient Age and Medical Complications: A Detailed Dual-Center Analysis of 395 Consecutive Elective and Emergency Procedures.

Background/Objectives: A popliteal artery aneurysm (PAA) is traditionally treated by an open PAA repair (OPAR) with a popliteo-popliteal venous graft interposition. Although excellent outcomes have been reported in elective cases, the results are much worse in cases of emergency presentation or with the necessity of adjunct procedures. This study aimed to identify the risk factors that might decrease amputation-free survival (efficacy endpoint) and lower graft patency (technical endpoint). Patients and Methods: A dual-center retrospective analysis was performed from 2000 to 2021 covering all consecutive PAA repairs stratified for elective vs. emergency repair, considering the patient (i.e., age and comorbidities), PAA (i.e., diameter and tibial runoff vessels), and procedural characteristics (i.e., procedure time, material, and bypass configuration). Descriptive, univariate, and multivariate statistics were used. Results: In 316 patients (69.8 ± 10.5 years), 395 PAAs (mean diameter 31.9 ± 12.9 mm) were operated, 67 as an emergency procedure (6× rupture; 93.8% severe acute limb ischemia). The majority had OPAR (366 procedures). Emergency patients had worse pre- and postoperative tibial runoff, longer procedure times, and more complex reconstructions harboring a variety of adjunct procedures as well as more medical and surgical complications (all p < 0.001). Overall, the in-hospital major amputation rate and mortality rate were 3.6% and 0.8%, respectively. The median follow-up was 49 months. Five-year primary and secondary patency rates were 80% and 94.7%. Patency for venous grafts outperformed alloplastic and composite reconstructions (p < 0.001), but prolonged the average procedure time by 51.4 (24.3-78.6) min (p < 0.001). Amputation-free survival was significantly better after elective procedures (p < 0.001), but only during the early (in-hospital) phase. An increase in patient age and any medical complications were significant negative predictors, regardless of the aneurysm size. Conclusions: A popliteo-popliteal vein interposition remains the gold standard for treatment despite a probably longer procedure time for both elective and emergency PAA repairs. To determine the most effective treatment strategies for older and probably frailer patients, factors such as the aneurysm size and the patient's overall condition should be considered.

Endovascular Transvenous versus Open Femoropopliteal Bypass.

Background and Objectives: Lower extremity arterial disease is one of the most prevalent manifestations of atherosclerosis. The results from numerous studies regarding the best revascularization method of an occluded superficial femoral artery have been conflicting. The aim of this study was to compare the patency of transvenous endovascular with open femoropopliteal bypass, both with vein and prosthetic grafts. To our knowledge, a direct patency comparison between transvenous endovascular and open femoropopliteal bypass has not been published. This could help elucidate which method is preferable and in which cases. Materials and Methods: Patients with complex TASC-C and D SFA lesions were offered endovascular transvenous or open bypass. A total of 384 consecutive patients with PAD requiring surgical treatment were evaluated for inclusion in this study. Three-year follow-up data were collected for 52 endovascular procedures, 80 prosthetic grafts, and 44 venous bypass surgeries. Bypass patency was investigated by Duplex US every 6 months. Kaplan-Meier plots were used to analyze primary, primary-assisted, and secondary patency for endovascular transvenous, autovenous, and prosthetic bypasses. Results: Primary, primary-assisted, and secondary patency in venous group at 3 years was 70.5%, 77.3%, and 77.3%, respectively. In the endovascular transvenous group, primary, primary-assisted, and secondary patency at 3 years was 46.2%, 69.2%, and 76.9%, respectively. The lowest patency rates at 3 years were noted in the prosthetic graft group with 22.5% primary, 26.6% primary-assisted, and 28.2% secondary patency. Conclusions: The saphenous vein is the best graft to perform in above-the-knee femoropopliteal bypass. Transvenous endovascular bypass is a viable option with comparable primary-assisted and secondary patency. Primary patency is substantially lower for endovascular transvenous compared to venous bypass. Patients treated with endovascular transvenous bypass will require a significant number of secondary procedures to provide optimal patency. Prosthetic grafts should only be used if no other option for bypass is available.

The Art of Cerebral Revascularization: An Illustrative Case Series of Bypass Techniques for Complex Intracranial Aneurysms

Complex intracranial aneurysms (CIAs) comprise a subset of lesions with defiant vascular architecture, difficult access, and prior treatment. Surgical management of CIAs is often challenging and demands an assessment on a case-by-case basis. The generational evolution of bypass surgery has offered a long-standing potential for effective cerebral revascularization. Herein, we aim to illustrate a single-center experience treating CIAs. The authors conducted a retrospective analysis of clinical records of patients treated with cerebral revascularization techniques at Hospital Nacional Dos de Mayo, Lima, Peru, during 2018-2022. Relevant data were collected, including patient history, aneurysm features on imaging, preoperative complications, the intraoperative course, aneurysm occlusion rates, bypass patency, neurological function, and postoperative complications. Seventeen patients (70.59% female; median age: 53years) with 17 CIAs (64.7% saccular; 76.5% ruptured) were included. The most common clinical presentation included loss of consciousness (70.6%) and headaches (58.8%). Microsurgical treatment included first-, second-, and third-generation bypass. In 47.1% of cases, an anastomosis between the superficial temporal artery and the M3 segment was predominantly used, followed by an A3-A3 bypass (29.4%), a superficial temporal artery-M2 bypass (17.6%), and an external carotid artery to M2 bypass (5.9%). The intraoperative aneurysm rupture rate was 11.8%. Postoperative complications included ischemia (40%), cerebrospinal fluid fistulas (26.7%), and pneumonia (20%). At hospital discharge, the median Glasgow Coma Scale score was 14 (range: 10-15). At the 6-month follow-up, 82.4% of patients had a modified Rankin Scale score ≤2, bypass patency was present in all cases, and the morbidity rate was 17.6%. CIAs represent a spectrum of defiant vascular lesions with a poor natural history. Bypass surgery offers the potential for definitive treatment. Our case series illustrated the predominant role of cerebral revascularization of CIAs with a critical case-by-case approach to provide optimal outcomes in a limited-resource setting.

Surgical Outcomes of Low-Flow Bypass Surgery in Intracranial Atherosclerotic Steno-Occlusive Diseases.

The role of bypass surgery in intracranial atherosclerotic steno-occlusive diseases (ICADs) remains controversial. We aimed to analyze the surgical outcomes of bypass surgery in patients with the ICADs in a single tertiary institution. Among 1018 cases of low-flow bypass surgery between 2003 and 2022, 215 patients with the ICAD refractory to medical treatment were finally enrolled in this study. Clinical and radiological outcomes were retrospectively evaluated, with survival analyses. All strokes, cerebral infarctions, and intracranial hemorrhages occurred in 12.1% (n = 26), 9.8% (n = 21), and 2.3% (n = 5), respectively, during the clinical follow-up of 54.6 ± 47.6 months (range, 0.6-237.8 months). Among all stroke events, 84.6% (n = 22) occurred within 30 postoperative days. The 2-year and 5-year cumulative risks of all strokes were 12.1% each. The mean modified Rankin Scale scores were 1.6 ± 1.1 (range, 0-5) preoperatively and 0.8 ± 1.2 (range, 0-6) at last (P < .01). The patency of direct bypass was 99.1% (n = 213) just before discharge and 96.3% (n = 184 of 191 patients with available tests) at the last angiographic follow-up of 27.0 ± 27.3 months (range, 2.3-97.3 months). All the patients with available data (n = 190) showed hemodynamic improvement on acetazolamide-challenged single-photon emission computed tomography with 99mTc-hexamethylpropyleneamine oxime during the follow-up of 38.6 ± 36.7 months (range, 2.3-158.6 months). Low-flow bypass surgery showed acceptable treatment outcomes in the prevention of recurrent stroke.

Dolichoectatic Posterior Inferior Cerebellar Artery Aneurysm Treated With Excision and Posterior Inferior Cerebellar Artery Double Reimplantation Bypass: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms account for 0.3% of all intracranial aneurysms, and they commonly present with a complex fusiform morphology that necessitates unique bypass strategies.1-5 An adolescent boy with a familial predisposition to aneurysmal subarachnoid hemorrhage was identified as harboring a fusiform aneurysm of the right distal PICA, characterized by 2 outflow branches. Our recommended treatment strategy involved a right far lateral craniotomy, followed by P1 PICA reanastomosis and P2 PICA reimplantation. Informed written consent was obtained. On exposure, the aneurysm was trapped, and the inflow and 2 outflow PICA branches were excised. Revascularization was established through a P1 PICA end-to-end reanastomosis using running continuous suturing techniques, followed by P2 PICA end-to-side reimplantation into a more distal portion of PICA. Subsequent indocyanine green videoangiography confirmed patency of the P2 PICA reimplantation; however, the initial P1 PICA reanastomosis was noted to be thrombosed. After several unsuccessful attempts to dissolve the thrombus, the decision was made to proceed with a P2 PICA side-to-side in situ reimplantation into the V4 segment of the vertebral artery. Indocyanine green videoangiography and postoperative digital subtraction angiography confirmed patency of the PICA double reimplantation bypass. The patient tolerated the procedure well and was discharged home at his neurological baseline. This video showcases the microsurgical treatment of a complex dolichoectatic, distal PICA aneurysm using a double reimplantation technique, in addition to highlighting bypass decision-making processes for managing complex PICA aneurysms.

External Scaffold for Venous Graft to Treat Chronic Limb-Threatening Ischemia: Results of the FRAME Vascular Support.

Background: The surgical treatment of chronic limb-threatening ischemia and optimal conduit choice are extensively debated. The presence of suboptimal autologous material, such as varicosities or venous aneurysms, might impair long-term outcomes. Therefore, kink-resistant external supports have been advocated in the recent literature to improve the conduit quality and outcomes. This study analyzes the FRAME external support in venous ectasic grafts in patients with chronic limb-threatening ischemia. Methods: From September 2017 to September 2023, a total of sixteen patients underwent CLTI surgery with FRAME external support for venous grafts. The inclusion criteria for FRAME applications were varicose or ectasic autologous material with a diameter ≥ 4.5 and ≤ 8 mm in an isolated segment or in the entire vein and a higher risk of bypass extrinsic compression (e.g., extra-anatomical venous bypass course). Results: Technical success and intraoperative patency were achieved in all cases. At 30 days, the limb salvage and survival rates were 100%. The primary bypass patency was 93.7% due to an early graft occlusion. No graft infection was registered. In one case, dehiscence of the surgical wound was treated by surgical debridement and antibiotic therapy. Minor amputation was required in four patients. Over a median follow-up of 32 months, two occlusions were observed; one was treated with reoperation and the other with major amputation. The primary patency was 68.7% and the assisted primary patency was 75%. Limb salvage rates observed during the entire follow-up period were 87.5%. No graft infections or dilatation of the reinforced veins were registered. Conclusions: For patients with CLTI undergoing infrainguinal bypass, satisfactory results in terms of patency and limb salvage rates were achieved using the autologous venous material, even if ectasic or varicose, with the vascular external support FRAME.

319 A Case Series of Direct Multi-territory Cerebral Revascularizations Using a Three-Vessel Anastomosis

INTRODUCTION: The ability to perform simultaneous, multi-territory cerebral bypass using a single interposition graft has significant utility for the revascularization of multiple cerebral territories that would otherwise require multiple constructs, serial anastomoses, or a combination of direct and indirect approaches. METHODS: Peri-operative data and outcomes were collected retrospectively for patients undergoing multi-territory cerebral revascularization using a three-vessel anastomosis over a 4-year period (2019-2023). RESULTS: Five patients underwent triple vessel bypass (median age 53 years [range 12-73]). Three patients with complex middle cerebral artery (MCA) aneurysms (one ruptured) were treated multi-territory external carotid artery (ECA)-M2-M2 revascularization using a saphenous vein interposition graft, followed by either proximal ligation or partial/complete aneurysm clip trapping. Two patients with predominately bilateral anterior cerebral artery (ACA) territory moyamoya disease were treated with proximal superficial temporal artery (STA)-A3-A3 revascularization using a radial artery or radial artery fascial flow-through free flap (RAFF) graft. Bypass patency was 100% and zero patients experienced surgery-related ischemia. One patient had new strokes from vasospasm after subarachnoid hemorrhage. One patient required a revision surgery for a post-operative hematoma and RAFF debridement that did not affect bypass patency or neurologic outcome. Median Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) scores on discharge were 4 (range 3-5) and 2 (range 0-5), respectively. GOS and mRS scores were stable or improved on follow up in 4/5 patients; one patient died from medical complications of their original stroke. CONCLUSIONS: In experienced hands, three-vessel anastomosis can be a viable option for the safe, simultaneous revascularization of multiple ACA and MCA territories.

Posterior Cerebral Artery–to–Superior Cerebellar Artery Side-to-Side Bypass via Extreme Lateral Supracerebellar Infratentorial Approach: Technical Note

Background and objectiveDifficult-to-treat aneurysms of the distal posterior cerebral artery (PCA) can often be treated by parent artery occlusion. A cerebrovascular bypass can complement PCA occlusion to curb the risk of ischemic complications.An in-situ bypass may be considered when the occipital artery or superficial temporal artery cannot serve as a bypass donor.This paper describes the use of a side-to-side bypass of superior cerebellar artery (SCA) as a donor to the posterior cerebral artery (PCA) via an extreme lateral supracerebellar infratentorial (ELSCIT) approach. This bypass approach can be a useful surgical strategy for PCA revascularization. MethodsA 40-year-old female patient underwent a side-to-side PCA-SCA bypass via the ELSCIT approach for the treatment of a complex and previously coiled PCA aneurysm.Bypass was followed by endovascular aneurysm and parent artery occlusion. ResultsPostoperatively, the patient experienced transient, partial trochlear nerve palsy of the left eye without ischemic lesions on MRI. The clinical condition was stable and angiography showed a patent bypass and complete aneurysm occlusion 12 months after surgery. ConclusionThe ELSCIT-approach offers access to the medial and distal PCA that is well suitable for a side-to-side PCA-SCA bypass. This type of approach and bypass may be of value when revascularization of a P2-P3 portion of the PCA is needed, but a suitable occipital artery (OA) or superficial temporal artery (STA) is not available.

Fluorescein videoangiography (FL-VAG) as a predictor of cerebral bypass patency

BackgroundThe fluorescein videoangiography (FL-VAG) has become a valuable adjunct tool in vascular neurosurgery. This work describes using the FL-VAG during bypass surgery and proposes a classification method for evaluating surgical results. MethodsWe analyzed 26 patients with 50 cerebral bypasses from September 2018 to September 2022. We used a three grades classification method based on the pass of intravenous fluorescein through the anastomosis. Grade 1 represents the synchronous and total filling of the "T" shape ("green T″) formed by the donor and recipient vessel, Grade 2, the asynchronous filling of the anastomosis (incomplete/asynchronous "green T″), and Grade 3, a non-patent anastomosis (absence of "green T″). ResultsOf the 26 patients, 8 underwent one bypass, 14 underwent double bypass, 2 underwent three bypasses, and 2 underwent four bypasses in two different interventions. The type of bypass was end-to-side anastomosis in 47 (94%) cases, internal maxillary artery to middle cerebral artery bypass with a radial artery graft (IMax-MCA anastomosis) in 2 (4%), and PICA-VA transposition in one (2%). We made 24 (48%) bypasses on the right side and 26 (52%) on the left side. After the initial surgery, thirty-nine (78%) bypasses were considered as Grade 1, 5 (10%) as Grade 2, and 6 (12%) as Grade 3. After intraoperative bypass patency assessment (IBPA), 45 (90%) of the bypasses were considered Grade 1 and remained patent on CTA. ConclusionsUsing FL-VAG and a three-tier classification method is a reliable tool to predict bypass patency. It is safe, low-risk, and available worldwide.

A direct aorta to segmental artery bypass for prevention of spinal cord ischemia after endovascular aortic repair

Spinal cord ischemia remains a persistent challenge after endovascular aortic aneurysm repair. We present a novel direct aorta to segmental artery bypass before aneurysm repair in a 64-year-old woman presenting with an enlarging aneurysm following dissection. Through an eighth intercostal incision, a polyester graft was sewn into the aorta using pledgeted sutures. An entry needle was used to directly access the previously treated aortic segment, and the opening was stented and angioplasty was performed to create inflow. Anastomoses were performed to a prominent left T10 segmental artery with a harvested saphenous vein. The patient remained neurologically intact postoperatively and the 1-month follow-up angiography demonstrated bypass patency.

Intracranial-intracranial bypass strategies for the treatment of complex intracranial aneurysms: anatomical characteristics and surgical intervention.

The effectiveness of revascularization for complex aneurysms is well-established. This study aimed to describe the technical characteristics and clinical efficacy of intracranial-to-intracranial (IC-IC) bypass for the treatment of complex intracranial aneurysms. We retrospectively reviewed all patients with aneurysms who underwent a preplanned combination of surgical or endovascular treatment and IC-IC bypass at our institution between January 2006 and September 2023. IC-IC bypass techniques included four strategies: type A (end-to-end reanastomosis), type B (end-to-side reimplantation), type C (in situ side-to-side anastomosis), and type D (IC-IC bypass with a graft vessel). During the study period, ten patients with aneurysms each underwent IC-IC bypass surgery. Aneurysms were located in the middle cerebral artery (60.0%), anterior temporal artery (10.0%), anterior cerebral artery (20.0%), and vertebral artery (10.0%). There were three saccular aneurysms (30.0%), two fusiform aneurysms (20.0%), one dissecting aneurysm (10.0%), and four pseudoaneurysms (40.0%). We performed the type A strategy on five patients (50.0%), type B on one (10.0%), type C on one (10.0%), and type D on three (30.0%). During a mean period of 68.3months, good clinical outcomes (modified Rankin Scale score, 0-2) were observed in all patients. Follow-up angiography demonstrated complete aneurysmal obliteration in all patients and good bypass patency in nine of ten patients (90.0%). The treatment of complex aneurysms remains a challenge with conventional surgical or endovascular treatments. IC-IC bypass surgery is a useful technique, associated with favorable clinical outcomes, for treating complex aneurysms.

Comparison of IMD and ICG videoangiography in combined bypass surgery: a single-center study.

Superficial temporal artery-middle cerebral artery (STA-MCA) bypass combined with an encephaloduromyosynangiosis (EDMS) had gained significant role in treating chronic cerebral ischemia. Invasiveness and costs of intraoperative digital subtraction angiography (DSA) limited its application in operations. To find the reliable parameters for determining bypass patency with intraoperative micro-Doppler (IMD) sonography and compare the diagnostic accuracy of indocyanine green (ICG) videoangiography with IMD in combined bypass. One hundred fifty bypass procedures were included and divided into patent and non-patent groups according to postoperative computed tomography angiography (CTA) within 72h. The surgical process was divided into four phases in the following order: preparation phase (phase 1), anastomosis phase (phase 2), the temporalis muscle closure phase (phase 3), and the bone flap closure phase (phase 4). The IMD parameters were compared between patent and non-patent groups, and then compared with the patency on CTA by statistical analyses. IMD with CTA, ICG videoangiography with CTA,IMD with ICGvideoangiography were performed to assess bypass patency. The agreement between methods was evaluated using kappa statistics. No significant differences of baseline characteristics were found between patent and non-patent group. Parameters in the STA were different between patent and non-patent groups in phases 2, 3, and 4. In patent group, Vm was apparently higher and PI was lower in phases 2, 3, and 4 compared with phase 1 (P < .001). In non-patent group, no differences of Vm and PI were found within inter-group. The best cutoff value of IMD in the STA to distinguish patent from non-patent bypasses was Vm in phase 4 > 17.5cm/s (sensitivity 94.2%, specificity 100%). In addition, the agreement for accessing bypass patency was moderate between ICGvideoangiography and CTA (kappa = 0.67), IMD and ICG videoangiography (kappa = 0.73), and good between IMD and CTA (kappa = 0.86). ICG videoangiography could directly display morphology changes of bypass. IMD could be used for providing half-quantitative parameters to assess bypass patency. Vm in phase 4 > 17.5cm/s suggesting the patency of bypass on CTA would be good. Also, compared with ICG videoangiography, IMD had more accuracy.

Usefulness of STA ultrasonography parameters after STA-MCA bypass in patients with moyamoya disease: A short review.

STA bypass assessment by ultrasonography after bypass surgery in patients with moyamoya disease is minimally invasive and can be performed repeatedly. With STA bypass assessment by ultrasonography, it was shown that in the short term, blood flow that passes through the STA peaks approximately 5days after the bypass surgery and then gradually decreases over 7days. In the medium and long terms, it has been shown that the blood flow through the bypass decreases, compared with that during the first postoperative week, and continues for approximately half a year. The ultrasonographic STA parameters can also clearly indicate bypass patency, but there remains some discussion regarding bypass function. Although some reports have tried to show that these parameters are also useful for predicting acute-phase TNEs and predicting the future of bypass function, no studies have yet examined these parameters in detail in relation to the state of cerebral circulation or degree of residual antegrade flow, and additional studies are needed in the future.

Exercise therapy results of postoperativ treated critical iliac artery stenosis (TASC II A and B) patients who were infected with the Covid 19

Introduction: Adequate individual physical activity after COVID 19 infection as a inevitable part of postoperative therapy of surgically treated vascular and endovascular patients witch still remains a scientific unexplored international neglected secret. General post-covid symptomatology is increasingly present in patients with surgical or endovascular procedures on the iliac segment in the form of a manifestation of various complaints that can affect the very accessibility of the choice of treatment according to the TASC II guidelines, but also affect physical activity and quality of life. Besides the medicament treatment, the management of moderate intensity exercise therapy and future consistency of self-controlled exercise after surgical and endovascular after treatment in iliac critic stenosis with other asymptomatic systemic atherosclerosis can be important factor to support and improve benefits of surgical and endovascular treatment outcome in variable symptomatology of POSTCOVID 19 patients treated classical surgical and endovascular. Goals: The focus is on priority of investigation of remodeling the pattern of cultural smoking behavior and increasing the dynamic of physical activity trying to prevent and avoid potential risk of sudden death, myocardial infarction, stroke graft (stent) occlusion, and cardiovascular mortality in patients with POSTCOVID 19 symptomatology in which is besides other asymptomatic systemic atherosclerosis is the main disease critical iliac artery stenosis (TASC II A and B). Scientifically unproven that sometimes can be associated with poor outcome of surgical intervention the which are in deficit with scientific studies to confirm these scientific observations. Second goals are to investigate the potential possibility of POST COVID 19 symptomatology associated with the success of classic surgical bypass or endovascular intervention and the possibility of reflection on physical activity after vascular intervention. Also the improving and secure the quality of life after successful surgical bypass and endovascular revascularization treatment with influence on primary iliac (TASC II A and B) vascular intervention potency one of main goals as well suppress permanent or permanent consequences of the Covid 19 virus during therapeutic surgical or endovascular procedures of the iliac segment (TASC II A and B) Traditional food as well wrong choice of diet and continuous fight with nicotinism is still remains generally main health threat. Subjects and Methods: 266 Symptomatic post COVID 19 Patients with were observed during 3 years (134 patients with surgical dacron reconstruction and 132 with endovascular treatmant of short segment critical iliac artery stenosis) Moderate interval Intensity Training with Short Interval Repetitions on standard treadmill procedure. Results: The connection of the outcome of surgical and endovascular treatment with post and long covid 19 symptomatology is possible and has a significant impact on the quality of the continuation of physical medication therapy. Difference between the surgical and endovascular groups was observed after the implementation of the treatment as well as factors affecting the outcome of therapy. the outcome is devastating with the prevention of the risk factor of nicotism as well as with the lack of physical activity in some groups. Conclusion: Primary potency after Three years of Endovascular procedure and Dacron bypass Revascularization, has shown as successful with support of supervised exercise training in POSTCOVID 19 patients. Nicotiism still remains highly potency outcome threat when supporting exercise therapy. Also, future and recent studies on this topic should expand their understanding of the effect of the COVID 19 virus on the body in this patients, as well as improving the quality of life in order to improve the patency of bypass or endovascular intervention on the arterial iliac segment.

Advanced fluorescence techniques in white matter fiber visualization for neurosurgical training.

Neurosurgical training requires a deep understanding of brain anatomy, especially white matter fiber pathways, to enhance surgical precision. Traditional dissection techniques, such as Klingler's white matter dissection, are essential, but newer methods can provide additional clarity. This study explores the application of a fluorescent-assisted technique to improve the visualization and understanding of white matter fibers during neurosurgical training. Twelve human brains were dissected following Klingler's protocol, with a focus white matter fiber pathway. Fluorescent alcoholic and oily solutions were applied to highlight the fibers. Ultraviolet (UV) blacklight and yellow monochromatic filters were used to enhance visualization. Dissections were documented through photography, and the effectiveness of the fluorescent techniques was analyzed. The application of UV light and fluorescent solutions enhanced the visualization of fiber pathways, particularly in regions with irregular fibers, such as the sagittal stratum. The alcoholic solution flowed along the anatomical paths of the fibers, aiding in their differentiation. The oily solution proved effective in specific areas, such as the internal capsule. The use of fluorescent techniques allowed for improved identification and anatomical detailing of major white matter tracts. The fluorescent-assisted dissection technique significantly enhances the visualization of white matter fibers, offering a valuable tool for neurosurgical training. This method deepens anatomical understanding, provides a three-dimensional perspective of brain structures, and can improve surgical outcomes. The study suggests potential applications in other fields, such as glioma simulation and bypass patency testing.

Analysis of Flow Through Extra-Anatomic Bypasses Between Supra-Aortic Branches Using Particle Image Velocimetry (PIV).

Supra-aortic extra-anatomic debranch (SAD) are prosthetic surgical grafts used to revascularize head and neck arteries that would be blocked during a surgical or hybrid procedure used in treating ascending and arch of the aorta pathologies. However, bypassing the supra-aortic arteries but not occluding their orifice might introduce potential for competitive flow that reduces bypass patency. Competitive flow within the bypasses across the supra-aortic arteries has not previously been identified. This research identified haemodynamics due to prophylactic inclusion of bypasses from the brachiocephalic artery (BCA) to the left common carotid artery (LCCA), and from the LCCA to left subclavian artery (LSA). Four model configurations investigated the risk of competitive flow and the necessity of intentionally blocking the proximal LSA and/or LCCA. Particle image velocimetry (PIV) was used to assess haemodynamics in each model configuration. We found potential for competitive flow in the BCA-LCCA bypass when the LSA was blocked, in the LSA-LCCA bypass, when the LCCA alone or LCCA and LSA were blocked. Flow stagnated at the start of systole within the RCCA-LCCA bypass, along with notable recirculation zones and reciprocating flow occurring throughout systolic flow. Flow also stagnated in the LCCA-LSA bypass when the LCCA was blocked. There was a large recirculation in the LCCA-LSA bypass when both the LCCA and LSA were blocked. The presence of competitive flow in all other configurations indicated that it is necessary to block or ligate the native LCCA and LSA once the debranch is made and the thoracic endovascular aortic repair (TEVAR) completed.

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

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

Long-term Patency of Retrograde Bypass Using a Distal Stump of the Parietal Superficial Temporal Artery for Moyamoya Disease.

There have been a number of anastomosis methods of bypass techniques reported for moyamoya disease. However, there are yet no randomized controlled trials conducted on the anastomosis method. Retrograde blood flow of the superficial temporal artery (STA) may be used as one of the donor options. Here, we examined the tolerability of retrograde bypass using a distal stump of the parietal STA (dsPSTA). Anastomosis between the dsPSTA and middle cerebral artery (MCA) was performed for consecutive patients with moyamoya disease whose parietal STA was visualized to be longer than 10 cm using contrast-enhanced computed tomography preoperatively. Retrospectively, we have examined its patency and clinical outcome. Retrograde dsPSTA-MCA bypass was performed in 22 hemispheres of 17 patients. The patency of retrograde dsPSTA-MCA bypass in all 22 anastomoses could be confirmed during follow-up periods (mean: 5.5, range: 2-15 years). No recurrence of ischemic events was observed. The dsPSTA-MCA bypass using retrograde blood flow has been determined as one of the many promising anastomosis methods, and long-term patency was achieved in moyamoya disease.

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

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. Retrospective review of perioperative data and outcomes for patients undergoing multiterritory cerebral revascularization using a 3-vessel anastomosis from 2019 to 2023. 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. The 3-vessel anastomosis technique can be considered for simultaneous revascularization of multiple intracranial territories.

RoboticScope-Assisted Microanastomosis in a Chicken Leg Model.

Background Many recent studies show that exoscopes are safe and effective alternatives to operating microscopes (OM). Developments of robotics and automation are present in neurosurgery with the appearance of a newer device such as RoboticScope (RS) exoscope with a digital three-dimensional (3D) image and a head-mounted display. The body of the RS is connected to a six-axis robotic arm that contains two video cameras, and serves as stereovision. This robotic arm allows accurate 3D camera motions over the field of view, giving the user a great degree of freedom in viewpoint selection. The surgeons may specify the direction and speed of the robotic arm using simple head movements when the foot pedal is pressed. Since its development in 2020, the RS has occasionally been used in neurosurgery for a multitude of procedures. Methods This study showcases vessel microanastomosis training on chicken legs using the RS. The aim of this study is to demonstrate the feasibility of the RS without a comparative analysis of the standard OM. The study was conducted in 2023 during a month-long trial period of the device at the Department of Neurosurgery of the Clinical Center of the University of Sarajevo. All procedures including RS-assisted anastomosis were performed by a neurosurgeon in anastomosis training (A.A.) supervised by a senior vascular neurosurgeon (E.B.). For the purpose of the study, we evaluated occlusion time in minutes, bypass patency with iodine, and overall satisfaction of the trainee in terms of light intensity, precision of automatic focus, mobility of the device, ergonomics, and convenience of the helmet. Results Ten RS-assisted microanastomoses were performed by interrupted suturing technique with 10.0 nylon thread. Bypass training included seven "end-to-side," two "end-to-end," and one "side-to-side" microanastomoses. The smallest vessel diameter was 1 mm. Occlusion time improved by training from 50 to 24 minutes, with contrast patency of the anastomoses in all cases without notable leakage of the contrast, except one case. Complete satisfaction of the trainee was achieved in 7 out of 10 cases. During this period, we also performed different RS-assisted surgeries including a single indirect bypass, convexity brain tumor resection, and microdiscectomies. Conclusion RS provides a new concept for microanastomosis training as an alternative or adjunct to the standard microscope. We found a full-time hands-on microsuturing without the need for manual readjustment of the device as an advantage as well as instant depth at automatic zooming and precise transposition of the focus via head movements. However, it takes time to adapt and get used to the digital image. With the evolution of the device helmet's shortcomings, the RS could represent a cutting-edge method in vessel microanastomosis in the future. Nevertheless, this article represents one of the first written reports on microanastomosis training on an animal model with the above-mentioned device.