High-flow Bypass Research Articles

Predictive Factors for the Occurrence of Visual and Ischemic Complications After Open Surgery for Paraclinoid Aneurysms of the Internal Carotid Artery.

To investigate the predictive factors for visual and ischemic complications after open surgery for paraclinoid aneurysms of the internal carotid artery (ICA). Thirty-eight consecutive patients with unruptured paraclinoid aneurysms of ICA operated on between 2009 and 2013 were included in this study. The male:female ratio was 6:32 and the ages ranged from 33 to 81 (mean: 60 ± 2). Twenty cases were asymptomatic and 18 had ophthalmological symptoms. The sizes of the aneurysms ranged from 2 to 35 mm (mean: 10.6 ± 9 mm). Twenty-three patients were treated by clipping and 15 by trapping with bypass (high-flow bypass in 11, and low-flow in 4). Twenty-four patients underwent removal of the anterior clinoid process. Among them, 8 underwent en bloc anterior clinoidectomy with a high-speed drill, and 16 had piecemeal excision with a microrongeur or ultrasonic bone curette. Intraoperative monitoring was performed using motor-evoked potentials (MEP) and visual-evoked potentials (VEP) in 27 and 15 cases, respectively. Complete obliteration of the aneurysm was achieved in 37 cases (97.4 %). The patency rate of bypass was 100 %. Postoperative worsening of visual acuity, including one case of blindness, was observed in six cases (11 %). Worsening of visual field defects occurred in 14 cases (38 %), but 10 of them were transient. Transient oculomotor nerve palsy occurred in six cases (15 %). Postoperative stroke was detected by diffusion-weighted imaging (DWI) in five cases (13 %), four of which were symptomatic. Statistical analysis showed that piecemeal anterior clinoidectomy was significantly safer than en bloc removal in preserving visual function. Trapping with high-flow bypass had a significantly greater risk of postoperative stroke than direct clipping. Intraoperative VEP monitoring might be useful for preventing postoperative worsening of visual function. Two-stage treatment with bypass and endovascular trapping might be safer than single-stage trapping alone.

High flowバイパス 20年後のグラフト血管に発生した破裂部分血栓化巨大動脈瘤の治療例

Cerebral revascularization with high-flow extracranial-intracranial (EC-IC) bypass is generally indicated in patients with complex intracranial aneurysms. This is the first reported case of aneurysm formation followed by rupture occurring on the graft itself, which was constructed to treat a patient with a giant internal carotid artery (ICA) aneurysm. A-78-year-old woman who had undergone right EC-IC bypass using a saphenous vein graft and ligation of the right cervical ICA to treat an unruptured right ICA giant aneurysm 20 years earlier presented with a subarachnoid hemorrhage (SAH). Computed tomography (CT) on admission revealed a ring-like mass in the right temporal lobe with an SAH. Angiography showed a fusiform aneurysmal formation on the graft just before the anastomotic site. We initially performed detachable coil embolization of the aneurysm with a stent in the acute stage. Next, endovascular trapping of the parent artery (saphenous vein graft) and removal of intraaneurysmal thrombus were performed, after we created a new high-flow EC-IC bypass using a radial artery. We report this case along with a review of the literature.

Surgical treatment of distal extracranial internal carotid artery aneurysms associated with pathological artery kinking

Extracranial internal carotid artery (ICA) aneurysms located at the entrance of the skull are a rare pathology. Surgical treatment is indicated for this pathology because of the risk of arterio-arterial embolism and the development of cerebrovascular disease. The domestic and international literature reports single cases or small group cases of successful surgical treatment of patients with distal internal carotid artery aneurysms associated with pathological kinking of the artery. Open surgery for aneurysms of this localization is complicated because of a high injury risk associated with the approach. Endovascular interventions are not always possible due to the presence of degenerative changes in the vascular wall and pathological artery kinking. We propose a surgical option for creating a high-flow ec-ic bypass between the external carotid artery and the M2 segment of the middle cerebral artery. The article describes the results of successful application of this technique in three patients with distal extracranial internal carotid artery aneurysms associated with pathological kinking of the artery.

The Valveless Saphenous Vein Graft Technique for EC-IC High-Flow Bypass: Technical Note

Extracranial to intracranial (EC-IC) high-flow bypass using radial artery or saphenous vein (SV) graft has remained vital for complex aneurysms. If an Allen test is positive, the radial artery cannot be harvested because of poor palmer collateral circulation. The valves are thought to be one of causes of SV graft failure. Herein we illustrate the "valveless SV graft technique" as bypass conduits. Between August 2014 and December 2014 at the Department of Neurosurgery at Teishinkai Hospital, 4 patients whose Allen test was positive underwent EC-IC bypass with the valveless SV graft for complex internal carotid artery (ICA) aneurysm. After SV harvesting, we identified the SV valve, cut it, and performed an end-to-end anastomosis using the fish mouth trimming technique. Graft patency was confirmed by computed tomography angiography. We have not encountered any problems related to graft failure, and all valveless SV grafts were patent during the follow-up period (median, 210 days; interquartile range, 93-287 days). The valveless SV graft technique is a useful technique in patients with complex ICA aneurysms who undergo EC-IC high-flow bypass with therapeutic ICA occlusion and whose Allen tests are positive.

Extracranial to intracranial by-pass anastomosis: Review of our preliminary experience from a low volume center in Egypt.

Background:Cerebral revascularization is a useful microsurgical technique for the treatment of steno-occlusive intracranial ischemic disease, complex intracranial aneurysms that require deliberate occlusion of a parent artery and invasive skull base tumors. We describe our preliminary experience with extracranial-to-intracranial by-passes at a low volume center; and discuss clinical indications and microsurgical techniques, challenges in comparison to large advanced referral centers.Materials and Methods:Twenty-seven patients with hemodynamic ischemia or complex aneurysms or skull base tumors were operated at Cairo University Hospitals in the period between May 2009 and June 2014. All patients operated by a low flow by-pass were operated through a superficial temporal artery to middle cerebral artery (MCA) anastomosis. All patients chosen for a high flow by-pass were operated using a radial artery graft interposed between the MCAs distally and the common or the external carotid artery proximally. Patency was confirmed at the end of surgery using appearance on the table and confirmed after surgery by transcranial color-coded duplex or computed tomography angiography. All patient data were prospectively collected and retrospectively analyzed at the end of surgery.Results:Nineteen patients (70.4%) were operated upon for flow augmentation and eight patients (29.6%) were operated upon for flow replacement. A total of 30 anastomoses were performed. All except one were patent which gives a patency rate of 96.3%. There was one death in the present series resulting from a hyperperfusion syndrome. 89.5% of patients with hemodynamic ischemia stopped having symptoms after surgery. All but one patient operated for hemodynamic ischemia showed a considerable cognitive improvement after surgery. None of the patients operated upon for flow replacement showed improvement of oculomotor nerve function in spite of adequate intraoperative decompression. All patients treated for flow replacement showed the absence of recurrence on follow-up.Conclusion:Our initial results for both low and high flow by-pass procedures in our low volume center indicate that such complex surgical procedures are possible with results comparable to those obtained in other larger referral centers throughout the world. This procedure not only represents a more definitive treatment when compared to other endovascular or radiation treatments but is also much less costly when compared to other treatment modalities.

Risk Factors for Low-Flow Related Ischemic Complications and Neurologic Worsening in Patients with Complex Internal Carotid Artery Aneurysm Treated by Extracranial to Intracranial High-Flow Bypass

The revascularization technique has remained indispensable for complex aneurysms. However, risk factors for low-flow related ischemic complications (LRICs) and neurologic worsening (NW) have been less well documented. We evaluated the risk factors for LRICs and NW in 67 patients treated with extracranial to intracranial bypass graft using radial artery or saphenous vein graft for complex internal carotid artery (ICA) aneurysm with ICA occlusion. Intraoperative middle cerebral artery pressure (MCAP) by backup superficial temporal artery to middle cerebral artery bypass was measured. The MCAP ratio was the ratio of the MCAP after release of the graft bypass to the initial MCAP. LRICs were defined as new neurologic deficits and ipsilateral cerebral blood flow reduction in single-photon emission computed tomography. Early and late NW were defined as an increase in 1 or more modified Rankin Scale at discharge and at the 12-month follow-up examination. During a median follow-up period of 13.3 months, LRICs were observed in 7 patients (10%). The Cox proportional hazards model showed that an MCAP ratio ≤0.80 was significantly related to LRICs. Multivariate logistic regression analysis revealed that perforating artery ischemia was significantly associated with early NW (n = 13, 19%) and late NW (n = 7, 13%). It also showed that LRICs were also significantly related to late NW. The present study showed that regardless of the graft type, the MCAP ratio was associated with LRICs, which were related to late NW in patients with complex ICA aneurysms treated by extracranial to intracranial high-flow bypass graft.

Surgical Treatment of 127 Paraclinoid Aneurysms with Multifarious Strategy: Factors Related with Outcome

Few reports have been published discussing surgical outcomes of paraclinoid aneurysms using multifarious treatments such as high-flow bypass. We retrospectively analyzed findings from 127 consecutive patients (19 males, mean age at surgery: 56.8 years, range: 19-81 years) at our hospital. The size of aneurysms ranged from 2.7-43.2 mm (mean: 6.9 mm). Extradural anterior clinoidectomy was used to clip small aneurysms. As large or giant aneurysms required a longer temporal occlusion period and often could not undergo simple clipping, high-flow bypass with anterior clinoidectomy or cervical internal carotid ligation was performed to reduce aneurysm blood flow and induce thrombosis. We reviewed a postoperative modified Rankin Scale (mRS), radiographic outcomes, cerebral infarction, and visual disturbance. In addition, we analyzed factors relating to the outcomes and complications, with focus on the aneurysm size, location, and type of surgical treatment. Good outcomes were achieved in all patients, as follows: mRS 0:100, mRS 1:16, mRS 2:11, and mRS 3-6:0. Among the 127 patients, complete exclusion of aneurysm was achieved in 119 cases (93.7%). Postoperative morbidity included ischemic lesions in 11 (8.6%) and visual disturbance in 24 (18.8%). Significant statistical differences were observed between ischemic complication and aneurysm size and location (P = 0.0001) and surgical treatment (P < 0.0001). Surgical treatment of unruptured paraclinoid aneurysm has high efficacy with good outcomes and a high rate of complete exclusion. However, the rate of visual disturbance is relatively high. Careful surgical techniques and intraoperative monitoring are therefore required.

Indications and Outcomes of Prophylactic and Therapeutic Extracranial-to-intracranial Arterial Bypass for Cerebral Revascularization.

Background:Extracranial-to-intracranial (EC-IC) arterial bypass is a technically demanding procedure used to treat complex cerebral artery diseases. The indications, proper surgical techniques, and outcomes of this procedure have been under debate over the recent decades.Methods:Between January 2004 and December 2012, 28 patients, including patients with cerebral artery occlusion, intracranial aneurysm, cranial base tumor, and Moyamoya disease, underwent EC-IC bypass. Patients’ records were retrospectively reviewed for demography, indications, complications, high-flow versus low-flow bypass, patency rate of bypass, and neurological outcome. The patients were sorted into prophylactic (n = 16) and therapeutic (n = 12) groups based on the preoperative presentation of their neurological symptoms. Follow-up evaluation was performed at a mean of 32.7 ± 24.3 months.Results:The overall patency rate of bypass was 100%, the postoperative stroke rate was zero, and the surgical complication rate was 14.3%. There was no significant difference in the bypass patency rate between the 2 groups or between the high-flow and low-flow bypass patients. Patients who underwent prophylactic bypass had minimal surgical and total complications (P = 0.03 and P < 0.01, respectively) and a better neurological outcome. Surgical complications were more common in patients who underwent therapeutic bypass (25%).Conclusions:The collaboration of neurosurgeons and plastic surgeons in performing EC-IC bypass can result in excellent outcomes with a high bypass patency rate and few complications, particularly for prophylactic EC-IC bypass.

Treatment of Symptomatic Bilateral Cavernous Carotid Aneurysms: Long-term Results of 6 Cases

Bilateral cavernous carotid aneurysms (CCAs) are very rare. A treatment strategy for symptomatic bilateral CCAs has not been established because of their complex pathogenesis. Here we report our treatment strategy and long-term results for 6 cases of symptomatic bilateral CCAs. From January 2007 to December 2013, we treated 6 patients (2 men and 4 women; mean age at first treatment, 56.0 years) with symptomatic bilateral CCAs. All patients began to experience unilateral symptoms. Five of the 6 underwent high-flow bypass (HFB) with parent artery occlusion (PAO), and 1 received PAO only. Mean follow-up period after the first treatment was 61.3 months. All symptoms improved after the treatment. Five contralateral CCAs became enlarged during the follow-up period. Of these, 4 became symptomatic. One patient received superficial temporal-middle cerebral artery bypass with PAO, 2 received HFB with PAO, and 1 refused treatment. Final modified Rankin Scale scores were 0 in 4 patients, 1 in 1 patient, and 2 in 1 patient. There was no mortality in this series. HFB with PAO is feasible as the first treatment for symptomatic bilateral CCAs. This treatment strategy steadies and simplifies future treatment of contralateral CCAs should they become symptomatic.

Bypass of the maxillary artery to proximal middle cerebral artery.

The objective of this work was to explore the feasibility of bypass between the maxillary artery (MA) and proximity of middle cerebral artery (MCA). Ten fixed and perfused adult cadaver heads were dissected bilaterally, 20 sides in total. The superficial temporal artery and its 2 branches were dissected, and outer diameters were measured. The MA and its branch were exposed as well as deep temporal artery; outer diameter of MA was measured. The lengths between the external carotid artery, internal carotid artery, maxillary artery, and proximal middle cerebral artery were measured. Ten healthy adults as targets (20 sides), inner diameter and blood flow dynamic parameters of the common carotid artery, external carotid artery, internal carotid artery, maxillary artery, superficial temporal artery, and its 2 branches were done with ultrasound examination. The mean outer diameter of MA (2.60 ± 0.20 mm) was larger than that of the temporal artery trunk (1.70 ± 0.30 mm). The mean lengths of graft vessels between the internal carotid artery, external carotid artery, and the bifurcation section of MCA (171.00 ± 2.70 and 162.40 ± 2.60 mm) were longer than the mean lengths of graft vessels between MA and MCA bifurcation section (61.70 ± 1.50 mm). In adults, the mean blood flow of the second part of MA (62.70 ± 13.30 mL/min) was more than that of the 2 branches of the superficial temporal artery (15.90 ± 3.70 mL/min and 17.70 ± 4.10 ml/min). Bypass between the maxillary artery and proximity of middle cerebral artery is feasible. It is a kind of effective high flow bypass with which the graft vessel is shorter and straighter than the bypass between internal carotid artery or external carotid artery and proximity of middle cerebral artery.

Radical Removal of Recurrent Malignant Meningeal Tumors of the Cavernous Sinus in Combination with High-Flow Bypass

Meningiomas or solitary fibrous tumors arising from the cavernous sinus (CS) are usually treated with radiosurgery to control growth. Surgical removal of cavernous tumors is indicated only for tumors extending outside the CS. However, even after adequate treatment, the tumor may exhibit recurrence or malignant transformation. We report a treatment option for recurrent meningeal tumors of the CS. In 4 patients with CS tumors that exhibited regrowth after multiple operations and radiosurgery, radical removal in combination with high-flow bypass was performed, and a vascularized muscle flap was used for reconstruction. One patient had a radiation-induced atypical meningioma, 2 patients had transformed atypical meningiomas, and 1 patient had a frequently recurring solitary fibrous tumor. No local recurrence was observed in any patients during a follow-up period of 13-41 months. In all patients, a Karnofsky performance scale score of >80 on admission was maintained at >70 at the final follow-up evaluation. Radical removal in combination with high-flow bypass provides favorable results and maintains quality of life in patients with recurrent CS meningeal tumors.

STA本幹をドナーとしグラフト血管を用いた端側吻合による頭蓋内血行再建術

Vascular reconstruction is often essential for the treatment of complex intracranial saccular or dissecting aneurysms. We describe the use of a short interposed graft using the saphenous vein or radial artery to connect the proximal side of the superficial temporal artery (STA) and the recipient's intracranial artery (e.g., the M2 or M3 segment of the middle cerebral artery or the A3 segment of the anterior cerebral artery). In this procedure, the STA and the short interposed graft are anastomosed in side-to-end fashion so that the distal side of the STA is preserved. In this way, the blood flow of the scalp skin flap is not disturbed.Bypass surgery using a short interposed graft was performed between December 2007 and January 2014 in 7 patients with complex intracranial aneurysms requiring parent artery occlusion or trapping. All 7 patients demonstrated good recovery according to the Glasgow Outcome Scale. No newly developed neurological deficits related to bypass surgery were observed in any of the 7 patients, all of whom had good graft patency after surgery. No scalp skin problems were observed.Short interposed grafting from the proximal side of the STA to the recipient intracranial artery without occlusion of the distal side of the STA is effective after occlusion of the parent artery. This “moderate flow bypass” technique may be a effective alternative to high-flow bypass surgery.

Urgent cerebral revascularization bypass surgery for iatrogenic skull base internal carotid artery injury.

When feasible, the management of iatrogenic internal carotid artery (ICA) injury during skull base surgery is mainly endovascular. To propose a cerebral revascularization procedure as a rescue option when endovascular treatment is not feasible. We retrospectively reviewed all extracranial-intracranial (EC-IC) bypass procedures performed between July 2007 and January 2014. From 235 procedures, we identified 8 consecutive patients with iatrogenic ICA injury managed with an EC-IC bypass. Injury to the ICA occurred during an endoscopic transsphenoidal surgery (n=3), endoscopic transfacial-transmaxillary surgery (n=1), myringotomy (n=1), cavernous sinus meningioma resection (n=1), posterior communicating artery aneurysm clipping (n=1), and cavernous ICA aneurysm coiling (n=1). Endovascular management was considered first-line treatment but was not successful. All patients received a high-flow EC-IC bypass. At a mean clinical/radiographic follow-up of 19 months (range, 3-36 months), all patients had a modified Rankin Scale score of 0 or 1. All bypasses remained patent. Iatrogenic injury of the skull base ICA is uncommon but can lead to lethal consequences. Many injuries can be treated with endovascular techniques. However, certain cases may still require a cerebral revascularization procedure.

Pipeline Embolization Device: Lessons Learned After 1000 Aneurysms

Giant intracranial aneurysms (GIAs) can be approached via microsurgical and endovascular techniques. Use of flow diversion devices has yielded favorable outcomes, and indications for cerebral revascularization have dramatically decreased.To evaluate the safety and validity of using internal maxillary artery (IMA) bypass with an interposed graft to treat GIAs.During a 6-year period, high-flow IMA bypass procedures were performed in 32 patients with GIAs at our institute. Intraoperative Doppler sonography, indocyanine green, and postoperative angiography were used to assess the patency of the graft conduit and the stability of the aneurysm. Neurologic function was assessed with the modified Rankin Scale.The mean GIA size was 33.7 mm (range, 25.3–64 mm), and all showed a nonsaccular morphology, except for 1 patient who underwent a first attempt at surgical clipping of a saccular aneurysm. Complete occlusion (65.6%, n = 21) or great diminishment (28.1%, n = 9) of the GIA was shown in 30 patients and the graft patency rate was 90.6% (n = 29). No deaths resulting from bypass surgery occurred. Functionally favorable outcomes (modified Rankin Scale score of 0–2) were recorded in 65.6% of patients at discharge, and the rate increased to 71.9% at the most recent follow-up (mean, 40.6 months). Surgical-related complications involving hydrocephalus and ischemic and hemorrhagic episodes were encountered in 5 patients, but 4 had complete regression of their neurologic symptoms.Considering the grave natural history and treatment complexity of these lesions, this study showed satisfactory results in the treatment of GIAs with IMA bypass.

EC-IC bypass for cavernous carotid aneurysms: An initial experience with twelve patients.

Aims:Need for performing a bypass procedure prior to parent artery occlusion in patients with good cerebral vascular reserve is controversial. We analyze our experience of 12 giant internal carotid artery aneurysms treated with extracranial-intracranial (EC-IC) bypass and proximal artery occlusion.Materials and Methods:Retrospective analysis of the case records of all complex carotid aneurysms operated in our institute since January 2009.Results:The study included eleven cavernous carotid aneurysms and one large fusiform cervical carotid aneurysm reaching the skull base. Preoperative assessment of cerebral vascular reserve was limited to Balloon test occlusion with hypotensive challenge. Eleven patients who successfully completed a Balloon test occlusion (BTO) underwent low flow superficial temporal artery to middle cerebral artery (STA-MCA) bypass, while one patient with a failed BTO underwent a high flow bypass using a saphenous vein graft. Parent artery ligation was performed in all patients following the bypass procedure. Check angiogram revealed thrombosis of the aneurysm in all patients with a graft patency rate of 81.8%. We had one operative mortality, probably related to a leak from the anastomotic site. The only patient who had a high flow bypass developed contralateral hemispheric infarcts and remained vegetative. All the other patients had a good recovery and with a Glasgow outcome score of 5 at last follow-up.Conclusion:We feel that combining EC-IC bypass prior to parent vessel occlusion helps in reducing the risk of post operative ischemic complications especially in situations where a complete mandated cerebral blood flow studies are not feasible.

Role of the emergency extra-intracranial bypass in acute occlusive arterial disease: evidence in the literature as to the benefit to young patients and an illustrative case of a patient with extra- and intracranial traumatic internal carotid artery occlusion

AbstractThe extra-intracranial bypass has been used in the treatment of patients with chronic cerebrovascular insufficiency. More recent studies have demonstrated the benefit of this technique to patients with arterial occlusion in the acute phase. We relate the case of a 19-year-old patient, victim of cervical trauma, who presented evidence of intra- and extracranial internal carotid artery (ICA) occlusion and progressive intra hospital clinical worsening. He underwent a high-flow bypass surgery with NIHSS at 17, progressing with progressive intra hospital improvement and in the outpatient segment achieved a NIHSS of 2 in 6 months of follow-up. We discuss the role of high- and low-flow bypass in chronic occlusive arterial disease, based on a review of the literature. We conclude that in spite of there being a divergence as to the indication for, and benefits of, these techniques in chronic occlusive arterial disease, in the acute phase, there appears to be a more evident benefit mainly in the young patients, whose etiology is the dissection of the ICA.

海綿静脈洞部大型・巨大内頚動脈瘤に対する頭蓋外内バイパス術とそのピットフォール

Our treatment modalities and techniques for intracavernous large or giant internal carotid artery (ICA) aneurysms have been changed based on past clinical experience. We report clinical results and pitfalls of bypass surgery for intracavernous ICA aneurysms. This study included unruptured symptomatic 37 intracavernous ICA aneurysms in 36 patients. Treatment methods were selected based on the anatomical features of the aneurysm and neurological/hemodynamic conditions during balloon test occlusion (BTO). Eleven aneurysms were treated without bypass surgery. Low flow bypass (STA-MCA anastomosis) was performed for 18 aneurysms, and eight aneurysms were treated with high flow bypass. A saphenous vein graft was originally used for high flow bypass, but it was changed with a radial artery because of the problem of long-term patency. ICA occlusion was accomplished by ligation of the cervical ICA alone in the early cases until we encountered a case with brain infarction due to emboli from the aneurysm after ICA ligation. Accordingly, ICA occlusion was performed by endovascular internal trapping two days after bypass surgery. There was, however, a case of graft thrombosis before ICA occlusion. We now occlude ICA by surgical trapping between the neck and the intracranial ICA immediately after revascularization. No patients had permanent ischemic neurological deficits due to cerebral hypoperfusion after ICA occlusion. Our treatment algorithm based on BTO was reliable. When the patients undergo bypass surgery, we perform ICA occlusion by surgical trapping between the neck and the intracranial portion.

The preparation of anastomosis site at the insular segment of middle cerebral artery.

Background:An anastomosis at the insular segment of the middle cerebral artery (M2) is often required in cerebral reconstruction with high- or low-flow bypass. It is necessary to create a shallow, wide, fixed, and bloodless anastomosis field to achieve a safe and quick anastomosis for low surgical morbidity. We describe a method to perform a safe and quick anastomosis.Methods:From 2009 to 2013, the technique was used in 20 procedures to create an extracranial M2 high-flow bypass. The Sylvian fissure was dissected wide open to expose the M2. A silicon sheet was laid under M2 and the absorbable gelatin-compressed sponges were inserted between M2 and the insula cortex to lift up the M2 and fix it. The rolling surgical sheets were placed at each edge of the dissected Sylvian fissure, instead of brain spatulas. Finally, a small suction tube was placed at the Sylvian fissure and cerebrospinal fluid was continuously sucked. The postoperative patency of the bypass was evaluated by three-dimensional computed tomographic angiography (3D-CTA) in the acute and chronic stages.Results:In all cases, the operation field acquired for the anastomosis was adequate. The average time required for the procedure was 19 min 27 s. Good patency of all high-flow grafts was confirmed by postoperative three-dimensional computed tomography angiography (3D-CTA).Conclusion:In our series, there were no technical complications related to the anastomosis at M2 performed according to our method.

破裂動脈瘤に待機的に治療を行うリスク

The optimal timing of surgery for patients with subarachnoid hemorrhage (SAH) has been debated over the last few decades. Recent literature largely advocates “early surgery,” namely within 48 hours after the onset of bleeding, for ruptured cerebral aneurysms. However, early surgery is not always safe for some complicated aneurysms. It can be even hazardous due to the vulnerability of the brain during the acute stage of SAH. Although elective surgery may be a useful option for better surgical outcome for these high-risk aneurysms, the actual risk of postponing surgery in the modern neurosurgical environment has not been well understood. We retrospectively analyzed the surgical outcome of our patients with SAH between January 2008 and September 2012. Our management policy for SAH is to perform clipping within 48 hours after hospitalization. Among a total of 235 patients with SAH, however, we found 43 patients who were treated after 48 hours from admission for various reasons. We analyzed the characteristics of these aneurysms, reasons for waiting, complications due to awaiting surgery, and outcomes. Among these 43 patients, the mean waiting period was 11 days (2–69 days, median; 6 days). During this period, we had four cases (9.3%) of rebleeding and three of these four patients died due to rerupture. Other complications included severe pneumonia in three (7.0%), symptomatic vasospasm and hydrocephalus in two (4.7%), respectively. These complications were all successfully treated. The reasons for elective surgery included a tight operating room schedule (23.3%), severe systemic conditions of patients (14.0%), the necessity of high flow bypass (18.6%), the time required for arranging endovascular surgery (14.0%), and elective clipping for aneurysms located in the posterior circulation (4.7%). Symptomatic vasospasm before surgery was observed in two cases (4.7%). Good outcome (GR and MD on Glasgow Outcome Scale) was achieved in 65.2% of patients treated during 3–7 day and in 60.0% of patients treated after seven days or later. The mortality was 11.6%, including three patients with rebleeding. Although “early surgery” is critical to treat patients with aneurysmal SAH, it is also true that “timing of surgery” is not the only factor affecting the outcome. Our study indicated that elective surgery can be an important option for aneurysms with high surgical risks in the acute phase of SAH under relatively acceptable complication rates and can provide useful data when the elective surgery is carefully planned for those selected cases.

"How I Do It:" Non-occlusive High Flow Bypass Surgery.

Giant intracranial aneurysms are a formidable challenge for treatment, considering their grim prognosis. Until lately, endovascular treatment options have been disappointing, and neurosurgical treatment results are by far the most promising. In the neurosurgical treatment of giant intracranial aneurysms, the non-occlusive nature of the ELANA anastomosis technique is a major advantage in flow replacement bypass surgery where large proximal arteries with higher flows need to be replaced or reconstructed. The construction of a deep intracranial anastomosis using the ELANA technique needs less vessel exposure than when using a conventional occlusive technique. This extra advantage facilitates the construction of anastomoses even on the ICA, MCA, ACA, P1, P2, SCA or BA, using the trans-Sylvian route only, without major skull base surgery. Several different types of EC-IC and IC-IC flow replacement bypass are now safely applicable due to the non-occlusive character of this technique.Future improvements of the technique are focused on sutureless applications, graft improvements and Flow Model Simulation. It is clear that not only conventional bypass techniques, but also, and even especially, the ELANA bypass technique, are of great value in the treatment of giant aneurysms.