Revascularization with saphenous vein bypasses for complex intracranial aneurysms

Surgical repair of torn base of ruptured middle cerebral artery trifurcation aneurysm

BACKGROUND

Treating complex middle cerebral artery (MCA) trifurcation aneurysms requires a delicate balance between achieving aneurysm obliteration and preserving vascular integrity. Various cerebral revascularization techniques, including bypass, and clip reconstruction are considered individually or in combination.

METHODS

This case report outlines a successful repair of a ruptured neck and base of MCA trifurcation aneurysm using a suturing-clip reconstruction technique. Temporary aneurysm trapping was implemented, with maintained elevated blood pressure to ensure collateral perfusion during repair of ruptured base and neck of MCA aneurysm.

CONCLUSION

The suturing-clip reconstruction exhibited long-term radiological stability, emerging as a valuable alternative for managing challenging MCA trifurcation aneurysms.

Stent infection and pseudoaneurysm formation after carotid artery stent treated by excision and in situ reconstruction with polytetrafluoroethylene graft: A case report

Background:

Stent infection after carotid artery stenting (CAS) can be a life-threatening postoperative complication, but there is a paucity of data due to its exceedingly low frequency. We report a case of stent infection with pseudoaneurysm formation after CAS that was treated through replacing the infected stent and pseudoaneurysm with a polytetrafluoroethylene (PTFE) synthetic vessel graft.

Case Description:

An 86-year-old man was treated for the right internal carotid artery with CAS in local hospital. One month after stenting, he suffered aspiration pneumonia and septicemia. Three months after stenting, swelling and tenderness of the right side of his neck appeared. His general condition deteriorated due to septicemia and he was unable to ingest anything by mouth as a result of decreasing levels of consciousness. He was transferred to our hospital. Computed tomography and digital subtraction angiography showed the presence of a pseudoaneurysm around the stent. The neck mass enlarged daily and surgical intervention was required to prevent closure of the airway. Stent and pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft were performed. The patient returned to his local hospital 36 days after surgery and had a modified Rankin Score of 5.

Conclusion:

Although the risk of reinfection is high due to the nature of artificial material, stent/pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft might be one of the best options for patients suffering stent infection after CAS. To the best of our knowledge, this is the first report of treatment using this material.

Microsurgery of Giant Intracranial Aneurysm: A Single Institution Outcome Study

Background

Giant intracranial aneurysms (GIAs) are treacherous lesions and in spite of the many advances, endovascular therapy (EVT) of GIAs is challenging.

Objective

A retrospective analysis of our results with microsurgery of GIAs is presented to examine the role of microsurgery in the current trend of EVT.

Materials and Methods

Between 1996 and 2019, 134 patients with 147 GIAs had microsurgery by the senior author in a single institute. The medical and imaging records for all the patients were reviewed. The patient outcome was determined by modified Rankin scale (mRS); ≤3 was considered as a good outcome. Statistical analysis was done using the SPSS program and odds ratios and their 95% confidence intervals were computed; a probability value of < 0.05 was considered significant.

Results

There were 123 aneurysms (83.7%) in the anterior circulation and 24 aneurysms (16.3%) in the posterior circulation. Overall 103 out of 134 (76.8%) patients had a good outcome postoperatively. Good preoperative mRS score (≤3) had an overall good prognosis in the postoperative period and was statistically significant (P = 0.000, odds ratio: 0.036, 95% CI: 0.008-0.171). Presence of subarachnoid hemorrhage (SAH) was also statistically significant for good outcome (P = 0.04, odds ratio: 2.898, 95% CI: 1.051-7.991), but age was not a significant prognostic factor. Mortality within 30 days of treatment was 4.47%.

Conclusion

GIAs need treatment because of their dismal natural history. Results of microsurgical treatment by a single surgeon of the large current series compare well with the results of EVT and justifies pursuing microsurgery for GIAs.

Final Results of the Prospective Multicenter Excimer Laser-Assisted High-Flow Bypass Study on the Treatment of Giant Anterior Circulation Aneurysms

BACKGROUND

Both conventional bypass utilizing temporary recipient vessel occlusion and the excimer laser-assisted nonocclusive anastomosis (ELANA) bypass technique are possible strategies in the treatment of giant aneurysms. These treatments have only been studied in single institutional retrospective studies. The potential advantage of the ELANA technique is the absence of temporary occlusion of major arteries, decreasing the risk of intraoperative ischemia.

OBJECTIVE

To investigate the risks and potential benefits of high-flow bypass surgery for giant and complex aneurysms of the anterior cerebral circulation. In addition, the effectiveness of the ELANA bypass procedure in the treatment of these aneurysms is determined.

METHODS

A total of 37 patients were included in 8 vascular neurosurgical centers in the United States, Canada, and Europe. A 30-d postoperative bypass follow-up was studied by using digital subtraction angiography and/or magnetic resonance angiography and computed tomography angiography to assess patency as well as by clinical monitoring in all patients.

RESULTS

In 35 patients, an ELANA high-flow bypass was performed and the aneurysm treated. Four patients had remaining neurological deficits after 30 d caused by stroke (11.4%). These strokes were not related to the ELANA anastomosis device.

CONCLUSION

This study does not prove that the ELANA technique has an advantage over conventional bypass techniques, but it appears to be an acceptable alternative to conventional transplanted high-flow bypass in this very-difficult-to-treat patient group, especially in select patients whom cannot be bypassed using conventional means in which temporary occlusion is considered to be not recommended.

Cerebral revascularization for the management of complex intracranial aneurysms: a single-center experience

OBJECTIVE

Because simple intracranial aneurysms (IAs) are increasingly treated endovascularly, neurovascular surgery has become focused on complex IAs that may require deconstructive aneurysm therapy with concomitant surgical bypass. The authors describe the decision-making process concerning cerebral revascularization and present outcomes that were achieved in a large case series of complex IAs managed with cerebral revascularization and parent artery occlusion.

METHODS

The authors retrospectively reviewed the medical records, including neuroimaging studies, operative reports, and follow-up clinic notes, of all patients who were treated at the National Brain Aneurysm Center between July 1997 and June 2015 using cerebral revascularization as part of the management of an IA. They recorded the location, rupture status, and size of each IA, as well as neurological outcome using the modified Rankin Scale (mRS), aneurysm and bypass status at follow-up, and morbidity and mortality.

RESULTS

The authors identified 126 patients who underwent revascularization surgery for 126 complex, atheromatous, calcified, or previously coiled aneurysms. Ninety-seven lesions (77.0%) were unruptured, and 99 (78.6%) were located in the anterior circulation. Aneurysm size was giant (≥ 25 mm) in 101 patients, large (10-24 mm) in 9, and small (≤ 9 mm) in 16 patients. Eighty-four low-flow bypasses were performed in 83 patients (65.9%). High-flow bypass was performed in 32 patients (25.4%). Eleven patients (8.7%) underwent in situ or intracranial-intracranial bypasses. Major morbidity (mRS score 4 or 5) occurred in 2 (2.4%) low-flow cases and 3 (9.1%) high-flow cases. Mortality occurred in 2 (2.4%) low-flow cases and 2 (6.1%) high-flow cases. At the 12-month follow-up, 83 (98.8%) low-flow and 30 (93.8%) high-flow bypasses were patent. Seventy-five patients (90.4%) undergoing low-flow and 28 (84.8%) high-flow bypasses had an mRS score ≤ 2. There were no statistically significant differences in patency rates or complications between low- and high-flow bypasses.

CONCLUSIONS

When treating challenging and complex IAs, incorporating revascularization strategies into the surgical repertoire may contribute to achieving favorable outcomes. In our series, low-flow bypass combined with isolated proximal or distal parent artery occlusion was associated with a low rate of ischemic complications while providing good long-term aneurysm control, potentially supporting its wider utilization in this setting. The authors suggest that consideration should be given to managing complex IAs at high-volume centers that offer a multidisciplinary team approach and the full spectrum of surgical and endovascular treatment options to optimize patient outcomes.

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.

“BONNET” BYPASS IN BRAIN REVASCULARISATION

The article describes the “bonnet” bypass, the type of extracranial-intracranial bypass. This technique is performed when ipsilateral arteries can’t be used as a donor when cerebral revascularization is required. The literature was analyzed and three main techniques of “bonnet” have been defined. The indications for performing “bonnet” bypass are determined, and the disadvantages are indicated. Alternative methods of revascularization are presented and technical details of graft protection are described. The “bonnet” bypass is a rare and laborious technique of cerebral revascularisation. However, it is an alternative and effective method of treatment to prevent serious ischemic disorders.

The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms. In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice. Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.

Intraoperative Test Occlusion as Adjustment of Extracranial-to-Intracranial Bypass Strategy for Unclippable Giant Aneurysm of the Internal Carotid Artery

BACKGROUND

There is still a controversy for low-flow extracranial-intracranial or high-flow extracranial-intracranial bypass with proximal occlusion in the treatment of unclippable giant internal carotid artery aneurysms.

CASE DESCRIPTION

A 61-year-old woman presented with a 1-month history of double vision. Neuroimages revealed an unclippable giant internal carotid artery aneurysm located from the cavernous sinus to proximal site of the posterior communicating artery. Ipsilateral A1 of the anterior cerebral artery was hypoplastic, and posterior communicating artery was patent. Intraoperative proximal test occlusion at cervical internal carotid artery under neurophysiological monitoring, instead of preoperative balloon test occlusion, was performed to assess whether low-flow bypass was sufficient. The monitoring was unchanged during test occlusion, and the aneurysm was successfully trapped without high-flow bypass. Neither ischemic lesion nor neurologic deficits were found postoperatively.

CONCLUSIONS

Intraoperative proximal test occlusion is useful to decide on the surgical procedure of revascularization in patients with unclippable internal carotid aneurysm.

Descending Branch of the Lateral Circumflex Femoral Artery Graft for Posterior Inferior Cerebellar Artery Revascularization

BACKGROUND

Posterior inferior cerebellar artery (PICA) revascularization can be achieved with relative ease when a contralateral PICA is present. However, without a contralateral PICA, identification of a suitable vessel alternative can be challenging due to a size mismatch.

OBJECTIVE

To propose the descending branch of the lateral circumflex femoral artery (DLCFA) to be an acceptable, if not preferred, arterial graft for PICA revascularization.

METHODS

Data from patients who underwent PICA revascularization with DLCFA grafts were obtained from an institutional review board-approved prospectively maintained database with informed consent from the patients.

RESULTS

Three patients, all presenting with ruptured aneurysms, were treated with PICA revascularization using the DLCFA. All cases achieved bypass patency and no ischemic events occurred during the bypass procedures. Graft spasm occurred in 2 patients. Two patients that presented with neurological deficits achieved excellent neurological outcomes and 1 suffered an anterior spinal artery stroke during a repeat endovascular treatment 1 wk after revascularization.

CONCLUSION

The DLCFA is favorable for PICA revascularization when a contralateral PICA is not a viable option.

High-Flow Bypass with Internal Carotid Artery to Middle Cerebral Artery Bypass Using Radial Artery Graft Through the Supramandibular-Subzygomatic Route for Giant Internal Carotid Aneurysm: Technical Case Report

BACKGROUND

A unique case of an internal carotid artery (ICA) giant aneurysm treated by high-flow bypass is presented. This patient had some anatomic variations in the neck region that posed problems for the high-flow bypass, and a new approach to address them is presented.

CASE DESCRIPTION

A 55-year woman presented with diplopia, abducens nerve palsy, severe headache, and disordered consciousness. She had a giant ICA aneurysm (diameter, 32 mm). Although high-flow bypass was considered, this patient had 3 anatomic issues that posed problems: an elongated styloid process, a high carotid bifurcation, and a meandering external carotid artery. Thus, some changes had to be introduced to proceed with the high-flow bypass. A tunnel radial artery (RA) graft was made between the supramandibular and subzygomatic areas, and an ICA-RA-M2 anastomosis was performed. The patient's preoperative symptoms improved gradually after surgery. Magnetic resonance imaging and computed tomography showed good patency of the RA graft and no ischemic change. She was discharged without neurological deficits.

CONCLUSIONS

This case provided 2 new methods for high-flow bypass: RA graft route and the anastomosis of the ICA in carotid bifurcation. To our knowledge, this is the first case report of a high-flow bypass with a tunnel created for the RA graft (supramandibular-subzygomatic route) and an ICA-RA-M2 anastomosis.

Flow diversion versus parent artery occlusion with bypass in the treatment of complex intracranial aneurysms: Immediate and short-term outcomes of the randomized trial

OBJECTIVE

We performed prospective randomized comparison of clinical and surgical outcomes of flow diversion versus PVO and bypass in patients with complex anterior circulation aneurysms.

PATIENTS AND METHODS

Open, prospective, randomized, parallel group, multicenter study of complex intracranial aneurysms treatment was conducted. Patients with complex intracranial aneurysms of anterior circulation with neck is more than 4 mm wide, dome/neck ratio is equal or less than 2:1, which is suitable for flow diversion and occlusion with bypass were included in the study. A total of 111 potential participants were enrolled since March 2015. Additional propensity score matching was performed with 40 patients in each group selected for analysis.

RESULTS

39 out of 40 patients (97.5%) from matched FD group reached good clinical outcome. In the matched bypass group acceptable outcome was achieved in 32 (80%) out of 40 patients (difference between groups p = 0.029). The morbidity and mortality rates were 15% and 5%, respectively. Difference in the rates of favorable outcomes, compared by χ2 met statistical significance (p = 0.014). The rate of complete aneurysm occlusion at 6 months was 42.5% in the FD group and 95% in surgical group (p < 0.0001). The rate of complete occlusion at 12 months was 65% in the FD group and 97.5% in surgical group. The difference between groups was still significant (p = 0.001). There were no significant differences between groups by occurrence of ischemic (p = 0.108) and hemorrhagic (p = 0.615) complications.

CONCLUSION

The study demonstrated superior clinical outcomes for endovascular flow diversion in comparison with bypass surgery in treatment of complex aneurysms. Though, both techniques grant similar percentage of major neurologic complications and comparable cure rate for cranial neuropathy. Nevertheless, flow diversion is associated with significantly lower early obliteration rate, thus possesses patient for risks of prolonged dual antiplatelet regimen and delayed rupture. Hence, it's important to stratify patient by the natural risk of aneurysm rupture prior to treatment selection.

Hemodynamic effect of bypass geometry on intracranial aneurysm: A numerical investigation

BACKGROUND AND OBJECTIVE

Hemodynamic analyzes are used in the clinical investigation and treatment of cardiovascular diseases. In the present study, the effect of bypass geometry on intracranial aneurysm hemodynamics was investigated numerically. Pressure, wall shear stress (WSS) and velocity distribution causing the aneurysm to grow and rupture were investigated and the best conditions were tried to be determined in case of bypassing between basilar (BA) and left/right posterior arteries (LPCA/RPCA) for different values of parameters.

METHODS

The finite volume method was used for numerical solutions and calculations were performed with the ANSYS-Fluent software. The SIMPLE algorithm was used to solve the discretized conservation equations. Second Order Upwind method was preferred for finding intermediate point values in the computational domain. As the blood flow velocity changes with time, the blood viscosity value also changes. For this reason, the Carreu model was used in determining the viscosity depending on the velocity.

RESULTS

Numerical study results showed that when bypassed, pressure and wall shear stresses reduced in the range of 40-70% in the aneurysm. Numerical results obtained are presented in graphs including the variation of pressure, wall shear stress and velocity streamlines in the aneurysm.

CONCLUSION

Considering the numerical results for all parameter values, it is seen that the most important factors affecting the pressure and WSS values in bypassing are the bypass position on the basilar artery (L_b) and the diameter of the bypass vessel (d). Pressure and wall shear stress reduced in the range of 40-70% in the aneurysm in the case of bypass for all parameters. This demonstrates that pressure and WSS values can be greatly reduced in aneurysm treatment by bypassing in cases where clipping or coil embolization methods can not be applied.

Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization

OBJECT Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options. METHODS Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm. RESULTS Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery-MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up. CONCLUSIONS The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.

Rescue Bypass for Revascularization After Ischemic Complications in the Treatment of Giant or Complex Intracranial Aneurysms

BACKGROUND

Surgical trapping or endovascular deconstruction commonly is used for the treatment of giant or complex intracranial aneurysms. Preoperative balloon test occlusion and cerebral blood flow studies and intraoperative neurophysiologic monitoring can indicate whether sufficient collateralization exists or whether revascularization is needed. Hemodynamic insufficiency can occur, however, despite passing these tests, necessitating posttreatment revascularization.

METHODS

We conducted a retrospective review of patients who underwent surgical or endovascular parent vessel occlusion for the management of giant or complex intracranial aneurysms and subsequently required rescue bypass for symptoms of hemodynamic insufficiency. Pre- and postrevascularization functional status was measured with the modified Rankin Scale.

RESULTS

During a 15-year period from 1997 to 2012, a rescue bypass was performed in 5 patients each harboring a giant or complex intracranial internal carotid artery (ICA) aneurysm that was treated with surgical trapping or endovascular deconstruction in a previous procedure. All bypasses were extracranial-to-intracranial and included cervical ICA to middle cerebral artery, subclavian to middle cerebral artery, and cervical ICA to supraclinoid ICA anastomoses via either a saphenous vein or radial artery graft. Functional outcome at time of last follow-up was improved in each patient (improvement in modified Rankin Scale of 1-3 points).

CONCLUSIONS

Ischemic complications must always be anticipated in the treatment of giant or complex intracranial aneurysms, even if pre- and intraoperative blood flow studies indicate sufficient collateralization. Here we show that extracranial-to-intracranial bypass is an effective option to rescue unanticipated hemodynamic insufficiency after parent vessel occlusion. This study emphasizes the need for cerebrovascular surgeons to maintain proficiency in complex bypass techniques.

Advances in Open Microsurgery for Cerebral Aneurysms

BACKGROUND:

Endovascular techniques introduced strong extrinsic forces that provoked reactive changes in aneurysm surgery. Microsurgery has become less invasive, more appealing to patients, lower risk, and efficacious for complex aneurysms, particularly those unfavorable for or failing endovascular therapy.

OBJECTIVE:

To review specific advances in open microsurgery for aneurysms.

METHODS:

A university-based, single-surgeon practice was examined for the use of minimally invasive craniotomies, surgical management of recurrence after coiling, the use of intracranial-intracranial bypass techniques, and cerebrovascular volume-outcome relationships.

RESULTS:

The mini-pterional, lateral supraorbital, and orbital-pterional craniotomies are minimally invasive alternatives to standard craniotomies. Mini-pterional and lateral supraorbital craniotomies were used in one-fourth of unruptured patients, increasing from 22% to 28%, whereas 15% of patients underwent orbital-pterional craniotomies and trended upward from 11% to 20%. Seventy-four patients were treated for coil recurrences (2.3% of all aneurysms) with direct clip occlusion (77%), clip occlusion after coil extraction (7%), or parent artery occlusion with bypass (16%). Intracranial-intracranial bypass (in situ bypass, reimplantation, reanastomosis, and intracranial grafts) transformed the management of giant aneurysms and made the surgical treatment of posterior inferior cerebellar artery aneurysms competitive with endovascular therapy. Centralization maximized the volume-outcome relationships observed with clipping.

CONCLUSION:

Aneurysm microsurgery has embraced minimalism, tailoring the exposure to the patient's anatomy with the smallest possible craniotomy that provides adequate exposure. The development of intracranial-intracranial bypasses is an important advancement that makes microsurgery a competitive option for complex and recurrent aneurysms. Trends toward centralizing aneurysm surgery in tertiary centers optimize results achievable with open microsurgery.

Revascularization for complex cerebral aneurysms

BACKGROUND AND PURPOSE

Complex cerebral aneurysms may require indirect treatment with revascularization. This manuscript describes various surgical revascularization techniques together with clinical outcomes.

METHODS

Thirty-two consecutive patients with complex cerebral aneurysm were managed from November 2005 to October 2008. Techniques used for revascularization were high-flow bypass, low-flow bypass, branch artery reimplantion, and primary reanastomosis. Physiologic and anatomic monitoring technologies, including electroencephalography, somatosensory evoked potential monitoring, microvascular doppler ultrasonography, and/or indocyanine green videoangiography were used intraoperatively to assess both brain physiology and vascular anatomy. Patient outcome was determined using the Glasgow Outcome Scale at discharge and at a mean of 12 months post operation (range 6-25 months).

RESULTS

Two cervical carotid aneurysms (6%) were resected followed by primary reanastomosis, 21 aneurysms (66%) were trapped following saphenous vein high-flow bypasses, five (16%) were clipped after superficial temporal or occipital artery low-flow bypasses, and four (12%) middle cerebral branch arteries were reimplanted. Of the 32 patients at discharge, 29 (91%) had a Glasgow Outcome Scale of four or five, two (6%) had severe disability, and one (3%) died.

CONCLUSION

Cerebral revascularization remains an effective and reliable procedure for treatment of complex cerebral aneurysms. Low morbidity and mortality rates reflect the maturity of patient selection and surgical technique in the management of these lesions.

Indocyanine green videoangiography for confirmation of bypass graft patency

OBJECTIVE

The aim of the study is to determine the efficacy of indocyanine green (ICG) videoangiography for confirmation of vascular anastomosis patency in both extracranial-intracranial and intracranial-intracranial bypasses.

METHODS

Intraoperative ICG videoangiography was used as a surgical adjunct for 56 bypasses in 47 patients to assay the patency of intracranial vascular anastomosis. These patients underwent a bypass for cerebral ischemia in 31 instances and as an adjunct to intracranial aneurysm surgery in 25. After completion of the bypass, ICG was administered to assess the patency of the graft. The findings on ICG videoangiography were then compared to intraoperative and/or postoperative imaging.

RESULTS

ICG provided an excellent visualization of all cerebral arteries and grafts at the time of surgery. Four grafts were determined to be suboptimal and were revised at the time of surgery. Findings on ICG videoangiography correlated with intraoperative and/or postoperative imaging.

CONCLUSION

ICG videoangiography is rapid, effective, and reliable in determining the intraoperative patency of bypass grafts. It provides intraoperative information allowing revision to reduce the incidence of technical errors that may lead to early graft thrombosis.

Endovascular stenting of an extracranial-intracranial saphenous vein high-flow bypass graft: Technical case report

Background:

The authors describe a case of endovascular stenting of an extracranial–intracranial saphenous vein high-flow bypass graft in the management of a complex bilateral carotid aneurysm case.

Case Description:

A 43-year-old woman was admitted with progressive visual field restriction and headache. Imaging studies revealed bilateral supraclinoid carotid aneurysms. The right carotid aneurysm was clipped and the left one was treated by an endovascular procedure, after performing an internal carotid artery–middle cerebral artery (ICA-MCA) saphenous vein bypass graft. A few months following the bypass procedure, a 70–80% stenosis of the graft was discovered and treated endovascularly with a stenting procedure. Follow-up at 36 months after the first operation showed the patency of the venous graft and no neurological deficits.

Conclusions:

Endovascular stenting of the extracranial–intracranial saphenous vein high-flow bypass graft is technically feasible when postoperative graft occlusion is discovered.

BYPASS SURGERY FOR COMPLEX BRAIN ANEURYSMS

OBJECTIVE

Bypass surgery for brain aneurysms is evolving from extracranial-intracranial (EC-IC) to intracranial-intracranial (IC-IC) bypasses that reanastomose parent arteries, revascularize efferent branches with in situ donor arteries or reimplantation, and reconstruct bifurcated anatomy with grafts that are entirely intracranial. We compared results with these newer IC-IC bypasses to conventional EC-IC bypasses.

METHODS

During a 10-year period, 82 patients underwent bypass surgery as part of their aneurysm management. A quarter of the patients presented with ruptured aneurysms and two-thirds presented with compressive symptoms from unruptured aneurysms. Most aneurysms (82%) had non-saccular morphology and 56% were giant sized. Common locations included the cavernous internal carotid artery (23%), middle cerebral artery (20%), and posteroinferior cerebellar artery (12%).

RESULTS

Forty-seven patients (57%) received EC-IC bypasses and 35 patients (43%) received IC-IC bypasses, including 9 in situ bypasses, 6 reimplantations, 11 reanastomoses, and 9 intracranial grafts. Aneurysm obliteration rates were comparable in EC-IC and IC-IC bypass groups (97.9% and 97.1%, respectively), as were bypass patency rates (94% and 89%, respectively). Three patients died (surgical mortality, 3.7%), and 4 patients were permanently worse as a result of bypass occlusions (neurological morbidity, 4.9%). At late follow-up (mean duration, 41 months), good outcomes (Glasgow Outcome Scale score 5 or 4) were measured in 68 patients (90%) overall, and were similar in EC-IC and IC-IC bypass groups (91% and 89%, respectively). Changes in Glasgow Outcome Scale score were slightly more favorable with IC-IC bypass (6% worse or dead after IC-IC bypass versus 14% with EC-IC bypass).

CONCLUSION

IC-IC bypasses compare favorably to EC-IC bypasses in terms of aneurysm obliteration rates, bypass patency rates, and neurological outcomes. IC-IC bypasses can be more technically challenging to perform, but they do not require harvest of extracranial donor arteries, spare patients a neck incision, shorten interposition grafts, are protected inside the cranium, use caliber-matched donor and recipient arteries, and are not associated with ischemic complications during temporary arterial occlusions. IC-IC bypass can replace conventional EC-IC bypass with more anatomic reconstructions for selected aneurysms involving the middle cerebral artery, posteroinferior cerebellar artery, anterior cerebral artery, and basilar apex.

Microsurgical management of incompletely coiled and recurrent aneurysms: trends, techniques, and observations on coil extrusion

OBJECTIVE

With the growing volume of aneurysms treated with endovascular methods and the unavoidable risks of incomplete coiling or recurrence, the volume of coiled aneurysms requiring surgical management is growing. We present a consecutive surgical experience with previously coiled aneurysms to examine clinical trends, the phenomenon of coil extrusion, microsurgical techniques, and morphological features affecting clippability.

METHODS

During a 10-year period, 43 patients underwent surgical management of an incompletely coiled or recurrent aneurysm (Gurian group B). Most patients (88%) presented initially with subarachnoid hemorrhage, most commonly (28%) located in the anterior communicating artery, and 42% of aneurysms were large or giant sized.

RESULTS

Twenty-one patients had incompletely coiled aneurysms and 22 patients had recurrent aneurysms, with a mean time to recurrence of 28 months. Coil extrusion was observed in 1 of the incompletely coiled (5%) and 12 of the recurrent aneurysms (55%). Overall, 33 aneurysms were clipped directly, 7 unclippable aneurysms were bypassed, and 3 were wrapped. Three patients died (surgical mortality, 7%), 1 patient (2%) experienced permanent neurological morbidity, and the remaining 39 patients (91%) had good outcomes (mean follow-up, 4.3 years).

CONCLUSION

This study demonstrated a sharp increase in the incidence of coiled aneurysms requiring surgery, reflecting the increasing numbers of patients opting for endovascular therapy initially. Coil extrusion occurs more often than expected, is often misdiagnosed on angiography as simply compaction, and seems to be a time-dependent process not seen acutely. Direct clipping is the preferred microsurgical treatment of coiled aneurysms and may be predicted by the relationship between coil width and compaction height (C/H < 2.5, or a wedge angle < 90 degrees). We recommend a bypass strategy for unclippable coiled aneurysms because it can be executed methodically; has predictable ischemia times; and is associated with more favorable results than thrombectomy, coil extraction, and clip reconstruction.

C-Port Flex-A–assisted automated anastomosis for high-flow extracranial-intracranial bypass surgery in patients with symptomatic carotid artery occlusion: a feasibility study

Object

Preliminary experience with the C-Port Flex-A Anastomosis System (Cardica, Inc.) to enable rapid automated anastomosis has been reported in coronary artery bypass surgery. The goal of the current study was to define the feasibility and safety of this method for high-flow extracranial-intracranial (EC-IC) bypass surgery in a clinical series.

Methods

In a prospective study design, patients with symptomatic carotid artery (CA) occlusion were selected for C-Port–assisted high-flow EC-IC bypass surgery if they met the following criteria: 1) transient or moderate permanent symptoms of focal ischemia; 2) CA occlusion; 3) hemodynamic instability; and 4) had provided informed consent. Bypasses were done using a radial artery graft that was proximally anastomosed to the superficial temporal artery trunk, the cervical external, or common CA. All distal cerebral anastomoses were performed on M2 branches using the C-Port Flex-A system.

Results

Within 6 months, 10 patients were enrolled in the study. The distal automated anastomosis could be accomplished in all patients; the median temporary occlusion time was 16.6 ± 3.4 minutes. Intraoperative digital subtraction angiography (DSA) confirmed good bypass function in 9 patients, and in 1 the anastomosis was classified as fair. There was 1 major perioperative complication that consisted of the creation of a pseudoaneurysm due to a hardware problem. In all but 1 case the bypass was shown to be patent on DSA after 7 days; furthermore, in 1 patient a late occlusion developed due to vasospasm after a sylvian hemorrhage. One-week follow-up DSA revealed transient asymptomatic extracranial spasm of the donor artery and the radial artery graft in 1 case. Two patients developed a limited zone of infarction on CT scanning during the follow-up course.

Conclusions

In patients with symptomatic CA occlusion, C-Port Flex-A–assisted high-flow EC-IC bypass surgery is a technically feasible procedure. The system needs further modification to achieve a faster and safer anastomosis to enable a conclusive comparison with standard and laser-assisted methods for high-flow bypass surgery.

Clipping of complex aneurysms with fenestration tubes: application and assessment of three types of clip techniques

OBJECTIVE

Straight fenestrated clips can be stacked to create tubes that reconstruct origins of branch arteries at the necks of complex aneurysms. Three variations of fenestration tubes were conceived and applied to a consecutive series of patients with aneurysms to determine their usefulness.

METHODS

Antegrade fenestration tubes are built with stacked, straight fenestrated clips with an open tube transmitting the efferent artery with forward blood flow. Retrograde fenestration tubes are also built with stacked, straight fenestrated clips, but the fenestration tube is closed with a nonfenestrated clip to reverse the direction of blood flow into the efferent artery that exits from the base of the tube. Aneurysm dome fenestration tubes encircle the dome rather than transmitting an efferent artery and use the tips of stacked, straight fenestrated clips to reconstruct the aneurysm neck.

RESULTS

During a 2-year period in which 465 aneurysms were treated microsurgically, 25 patients had 26 aneurysms clipped with fenestration tubes (antegrade tubes, 15 aneurysms; retrograde tubes, four aneurysms; dome tubes, seven aneurysms). Angiographically, 92% of the aneurysms were completely eliminated with no branch artery occlusions. Neurologically, good outcomes were observed in 84% of the patients (Glasgow Outcome Scale score 5 or 4) with 96% either improved or unchanged.

CONCLUSION

Clip reconstruction with fenestration tubes is another microsurgical technique that can be used to treat aneurysms with large or giant-sized efferent arteries that adhere to the aneurysm and/or unusual branch anatomy. Fenestration tubes are safe and effective, and they are used more frequently than expected for what might seem to be a subtle technical nuance. This technique relies on intraoperative adjuncts such as temporary clipping, careful application of clips to preserve the patency of branch arteries, and technology to detect inadvertent branch occlusions.

Automated, compliant, high-flow common carotid to middle cerebral artery bypass

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial–intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection.

The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery.

The C-Port system facilitates the performance of a high-flow extracranial–intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.

TREATMENT OF GIANT MIDDLE CEREBRAL ARTERY ANEURYSMS WITH A FLOW REPLACEMENT BYPASS USING THE EXCIMER LASER-ASSISTED NONOCCLUSIVE ANASTOMOSIS TECHNIQUE

OBJECTIVE

To define the clinical value of the flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis (ELANA) technique in the treatment of patients with a noncoilable, nonclippable giant intracranial aneurysm of the middle cerebral artery (MCA).

METHODS

Between 1999 and 2006, 22 patients with a giant intracranial aneurysm of the MCA were treated in our hospital with an ELANA flow replacement bypass and MCA occlusion. We collected data on patient characteristics, operative aspects, complications, and functional health scores using the modified Rankin Scale. Mean follow-up was 3.6 years (range, 0.2–7.7 yr).

RESULTS

We were able to construct a patent bypass in 20 (91%) of 22 patients. All 34 ELANA attempts resulted in a patent anastomosis with a strong backflow directly after ELANA catheter retraction. The patients did not need to undergo temporary occlusion in any of the ELANA constructions. Mean ± standard deviation intracranial-to-intracranial bypass flow was 53 ± 13 ml/min. MCA aneurysm treatment was attempted in all 20 patients who had a patent bypass and was successful in 19 of them. There was a fatal hemorrhagic complication in one patient (5%), a nonfatal hemorrhagic complication in three patients (14%), and a nonfatal ischemic complication in six patients (27%). At follow-up, 17 patients (77%) had a functionally favorable outcome (modified Rankin Scale score at follow-up was the same as or less than the preoperative modified Rankin Scale score). All of these patients were independent at follow-up (modified Rankin Scale score ≤2).

CONCLUSION

This study demonstrates satisfactory results in the treatment of giant MCA aneurysms with an ELANA flow replacement bypass, considering the very grave natural history and treatment complexity of these lesions. The ELANA technique is a useful tool in the treatment armamentarium of the vascular neurosurgeon.

External carotid artery to middle cerebral artery bypass with the saphenous vein graft

Patients with occlusive cerebrovascular disease who have failed maximal medical therapy, which consists of antiplatelet agents as well as maximizing modifiable risk factors such as blood pressure, cholesterol, smoking cessation, and obesity, and whose lesions are not amenable or have not responded to the more common vascular procedures (i.e., carotid endarterectomy or stenting) are considered candidates for an extracranial-intracranial bypass. Additionally, for a patient to be a candidate, he/she must have an adequate graft vessel. Typically, this vessel is the superficial temporal artery. However, oftentimes, the superficial temporal artery is an inadequate vessel or the patient requires a high-flow conduit. It is in these patients that use of the saphenous vein should be considered. In this report, we detail the technical aspects of performing an extracranial-intracranial bypass by using a saphenous vein graft.

Use of radial artery grafts in extracranial-intracranial revascularization procedures

Cerebral revascularization procedures have been used in the clinical management of actual or threatened cerebral ischemic states and unclippable cerebral aneurysms. An alternative to a low-flow bypass graft (for example, with the superficial temporal artery) is the use of high-flow grafts created using the saphenous vein (SV) or radial artery (RA). These high-flow grafts are particularly useful when otherwise adequate collateral flow is insufficient to enable sacrifice of the parent vessel without the risk of cerebral ischemia. In their clinical series of 13 patients who underwent high-flow bypass with an RA graft, the authors describe 8 women and 5 men whose ages ranged from 44 to 69 years (mean 57.84 +/- 9.05 years). Indications for RA graft bypass were unclippable aneurysms in 10 patients and occlusive cerebrovascular disease in 3 patients. The authors review the properties of the 2 most common conduits, the SV and RA grafts. They present the technique of high-flow extracranial-intracranial bypass produced using RA grafts in the management of occlusive atherosclerotic disease and complex intracranial aneurysms that are not otherwise amenable to either clip ligation or coil occlusion.

Management of complex, surgically intractable intracranial aneurysms: the option for intentional reconstruction of aneurysm neck followed by endovascular coiling

BACKGROUND

A limited series of patients with aneurysm were reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex, surgically intractable aneurysms.

METHODS

Four patients were managed in Fujita Health University with a multimodality approach: intentional reconstruction of the aneurysm neck followed by endovascular coiling.

RESULTS

A total of 5 aneurysms were treated, of which 3 were large or giant in size, and 3 were fusiform or multilobulated. Complete angiographic obliteration was confirmed in 4 aneurysms (80%). All patients had a good outcome (Glasgow Outcome Scale score 5; mean follow-up, 64 months).

CONCLUSION

As for complex, surgically intractable aneurysms, the intentional reconstruction of the aneurysm neck followed by endovascular coiling should be considered more often.

Estimating the hemodynamic impact of interventional treatments of aneurysms: numerical simulation with experimental validation: technical case report

OBJECTIVE

The goal of this study was to use phase-contrast magnetic resonance imaging and computational fluid dynamics to estimate the hemodynamic outcome that might result from different interventional options for treating a patient with a giant fusiform aneurysm.

METHODS

We followed a group of patients with giant intracranial aneurysms who have no clear surgical options. One patient demonstrated dramatic aneurysm growth and was selected for further analysis. The aneurysm geometry and input and output flow conditions were measured with contrast-enhanced magnetic resonance angiography and phase-contrast magnetic resonance imaging. The data was imported into a computational fluid dynamics program and the velocity fields and wall shear stress distributions were calculated for the presenting physiological condition and for cases in which the opposing vertebral arteries were either occluded or opened. These models were validated with in vitro flow experiments using a geometrically exact silicone flow phantom.

RESULTS

Simulation indicated that altering the flow ratio in the two vertebrals would deflect the main blood jet into the aneurysm belly, and that this would likely reduce the extent of the region of low wall shear stress in the growth zone.

CONCLUSIONS

Computational fluid dynamics flow simulations in a complex patient-specific aneurysm geometry were validated by in vivo and in vitro phase-contrast magnetic resonance imaging, and were shown to be useful in modeling the likely hemodynamic impact of interventional treatment of the aneurysm.

Treatment of a partially thrombosed giant aneurysm of the vertebral artery by aneurysm trapping and direct vertebral artery-posterior inferior cerebellar artery end-to-end anastomosis: technical case report

OBJECTIVE

The purpose of this article is to focus for the first time on the operative management of a direct vertebral artery (VA)-posterior inferior cerebellar artery (PICA) end-to-end anastomosis in a partially thrombosed giant VA-PICA-complex aneurysm and to underline its usefulness as an additional treatment option.

METHODS

The operative technique of a direct VA-PICA end-to-end anatomosis is described in detail. The VA was entering the large aneurysm sack. Distally, the PICA originated from the aneurysm sack-VA-complex. The donor and recipient vessel were cut close to the aneurysm. Whereas the VA was cut in a straight manner, the PICA was cut at an oblique 45-degree angle to enlarge the vascular end diameter. Vessel ends were flushed with heparinized saline and sutured. The thrombotic material inside the aneurysm sack was removed and the distal VA clipped, leaving the anterior spinal artery and brainstem perforators free.

RESULTS

The patient regained consciousness without additional morbidity. Magnetic resonance imaging scans revealed a completely decompressed brainstem without infarction. The postoperative angiograms demonstrated a good filling of the anastomosed PICA.

CONCLUSION

Despite the caliber mistmatch of these two vessels the direct VA-PICA end-to-end anastomosis provides an accurate alternative in addition to other anastomoses and bypass techniques, when donor and recipient vessels are suitable and medullary perforators do not have to be disrupted.