Low-flow Bypass Research Articles

Hunterian Ligation With Distal Revascularization for Management of a Previously Coiled Giant Internal Cerebral Artery Aneurysm: 2-Dimensional Operative Video.

Unclippable giant aneurysms pose a significant microsurgical challenge. Options for management are highly dependent on the aneurysm characteristics and cerebrovascular anatomy. Hunterian (proximal) ligation with either high-flow or low-flow distal revascularization is an option for the treatment of aneurysms of the internal carotid artery (ICA). This patient had a multiply recurrent supraclinoid ICA aneurysm following endovascular treatment and progressive ipsilateral homonymous hemianopsia. In preparation for the clip occlusion of the proximal ICA, the patient underwent a balloon test occlusion of the ICA, which had a negative result, indicative of tolerance. A pterional craniotomy was used to perform a low-flow bypass, superficial temporal artery to M2, and clip occlusion of the proximal ICA. The patient tolerated the procedure well with some pressure-dependent contralateral symptoms, which resolved. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Moyamoya Disease Superficial Temporal Artery-to-Middle Cerebral Artery Onlay: 2-Dimensional Operative Video.

The most frequently performed low-flow bypass procedure is the superficial temporal artery (STA) to middle cerebral artery (MCA) bypass. If available, a suitable M2 or M3 cortical branch is anastomosed to the donor vessel. This patient had severe moyamoya disease with an ipsilateral perfusion deficit and transient ischemic attacks. Given the need for revascularization, an STA-to-MCA bypass was performed. There was no suitable recipient M3 branch for direct anastomosis, and therefore an indirect bypass was performed by onlaying the STA onto the cortical surface and suturing the adventitia of the STA to the arachnoid of the underlying cortex. The dural leaflets were then inverted to potentiate further revascularization of the underlying cortex. The patient remained at their neurological baseline and demonstrated an enhanced perfusion of the ipsilateral MCA territory on follow-up evaluation. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Long-term patency in cerebral revascularization surgery: an analysis of a consecutive series of 430 bypasses.

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. 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. 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. 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.

Development of vascular substitutes for low-flow peripheral bypass grafting – a review

The development of alow-flow vascular prosthesis is avery topical issue. The authors present apathway for the development of aprosthesis with optimal properties based on the idea of mimicking the characteristics of abiological model (saphenous vein graft) and programming these properties in the model of the prosthetic substitute. The vascular prosthesis presented consists of three layers - anon-absorbable scaffold representing vascular &#8220;media&#8221;, and two absorbable collagen layers - pseudointima and pseudoadventitia. The basic methods of physical testing are presented - the single axis stretch test and inflation-extension test, as well as other procedures that affect the final properties. These include collagen curing, antithrombotic treatment of the inner layer and the use of sterilization methods. The designed new graft was successfully implanted in an ovine model.

Insurance and Flow-Alteration Superficial Temporal Artery to Middle Cerebral Artery (STA-MCA) Bypass in Management of Complex Anterior Intracranial Circulation Aneurysms in Postendovascular Era

Optimal management of complex anterior circulation aneurysms is an enigmatic challenge because of frequent involvement of major vessel bifurcation, choroidal vessels, and lenticulostriate/thalamostriate perforators. Cerebral ischemia associated with prolonged clipping time is a major concern pertinent to their surgical management, especially in patients with poor cross-flow. To circumvent this hurdle, single/double-barrel low-flow superficial temporal artery (STA) to middle cerebral artery (M3/M4-MCA) can be performed, which can maintain distal cerebral perfusion while facilitating safe clip reconstruction of complex MCA and supraclinoidal internal carotid artery (ICA) aneurysms involving ICA bifurcation or supraclinoidal ICA aneurysms with poor cross-circulation-insurance bypass, as well as supplement/alter blood flow after MCA aneurysm trapping-flow-alteration bypass. A retrospective chart review of consecutive neurosurgical patients operated over 2 years at this center was performed. Patients with complex MCA and ICA aneurysms who were treated with STA-MCA bypass were included. The clinical profile, pre- and postoperative images, intraoperative imaging, and patient outcomes were recorded. Surgical reconstruction of aneurysm was the treatment of choice due to involvement of choroidal/thalamostriate perforators, MCA/ICA bifurcation, complex aneurysm morphology, or dissecting/thrombosed nature of aneurysm. STA-MCA low-flow bypass was performed using M3/M4 segment of MCA as the recipient in anticipation ofprolonged temporary clipping time on M1-MCA, supraclinoidal ICA aneurysms with suspected ICA terminus involvement, or need for possible trapping of fusiform MCA aneurysm. The saccular/fusiform part of aneurysm was clip reconstructed and the partially thrombosed dissecting segment was opened for thrombectomy and trapped using proximal and distal clips after good patency of bypass was confirmed. The distal MCA flow was restored adequately and confirmed intraoperatively using indocyanine green angiography and micro-Doppler ultrasonography. MCA (n= 4) and supraclinoid-ICA (n= 1) aneurysms were managed successfully using this strategy, which involved 6 STA-MCA bypass procedures (insurance and flow-alteration bypass, 3 each). Postoperative check angiograms demonstrated patent bypass in all 5 patients. Four patients had favorable outcome (modified Rankin Scale score 0/1); one had recovering hemiparesis and aphasia (modified Rankin Scale score 4). This series highlights the surgical strategy and safety for successfully managing complex MCA and ICA aneurysms using low-flow STA-MCA revascularization procedures.

Surgical Strategies and Clinical Results of Site-Specific Treatment Using High-Flow Bypass for Ruptured Blood Blister–Like Anterior Wall Aneurysms of the Internal Carotid Artery

Surgical treatment of ruptured blood blister-like aneurysms (BBAs) arising from the internal carotid artery (ICA) is challenging. We retrospectively reviewed the results of our surgical strategies tailored for each aneurysm site. All ruptured ICA BBAs treated between 2003 and 2015 were reviewed. Aneurysms on the lateral side of the ICA were classified as type A, on the medial side of C2 as type B, and on the medial side of C1 as type C. The principal strategy was high-flow bypass (HFB) by use of a radial artery graft, with clipping, trapping, or proximal occlusion selected on the basis of aneurysm type. The results of each treatment were examined. This study included 20 patients. There were 11 type A aneurysms (55%), 2 type B (10%), and 7 type C (35%). HFB was used in 13 patients (65%) and low-flow bypass in 4 (20%). Except for 1 case, no other cases of rerupture or recurrence occurred. Severe ischemia due to cerebral vasospasm was confirmed in 4 of 20 patients (20%), 3 of whom had not received HFB. Modified Rankin Scale score was 0-2 in 16 of 20 patients (80%). Inadequate cerebral blood flow is a distinct possibility even with HFB, so parent artery flow should be preserved to protect against ischemia whenever possible. However, if preservation of the anterior choroidal artery or posterior communicating artery during clipping or trapping is difficult, HFB combined with occlusion of the proximal portion of the ICA in the neck is a feasible option.

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

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. 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. 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. 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.

High Flow Bypass for Cavernous Carotid Aneurysms

Abstract Introduction and objective: High flow extracranial to intracranial (HF EC-IC) cerebral revascularisation may be necessary in the management of complex skull base tumours and intracranial aneurysms. Bypass grafting can be considered high flow when a radial artery or the saphenous vein is interposed between the extracranial carotids arteries and intracranial vessels. The decision as to whether to use a low flow or high flow bypass is determined by the anticipated cerebral blood flow needed and the availability of a supply source. In this study, we have used this method to bypass for two cases of giant aneurysms of the cavernous sinus part of the ICA. Methods: Two cases of giant ICE aneurysm not amenable to clipping or coiling were taken since 2016. Patients were treated in Neurosurgery department of Fujita Health University Banbuntane Hotokukai Hospital, Nagoya, Japan. During bypass surgery, intraoperative methods were used to determine the patency of the graft artery: Doppler sonography and indocyanine green (ICG) Dual-Image Videoangiography (DIVA). Results: Two patients with symptomatic large and giant cavernous carotid aneurysms were evaluated as not amenable for clipping or endovascular treatment due to location and size of the aneurysm and associated high morbidity risk with these treatment options. In both cases radial artery graft was used for high-flow EC-MCA bypass and proximal internal carotid artery was ligated. Additionally, for high-flow bypass was performed superficial temporal artery (STA) to middle cerebral artery (MCA) bypass. DIVA, ICG and Doppler sonography were used multiple times to assess the patency of graft artery. In one case there was not complete ligation of the IC after postop DSA, the next day was performed reintervention to completely ligate IC. Postoperative course was uneventful, there were no mortality or morbidity. Follow-up showed good recovery and postoperative CT and DSA showed complete occlusion of ligated IC and patent functioning arterial graft. Conclusions: Cavernous carotid aneurysms (CCA) are rare and pose considerable challenges in management. A bypass procedure before parent artery occlusion, preferable to reduce the risks of postocclusion stroke. Intraoperative Doppler sonography and DIVA makes it easy to check the patency of the graft. DIVA is superior over Doppler or ICG in terms of better visualization of related anatomical structures.

Modified closed chamber sutureless technique for anomalous pulmonary venous connection.

Visibility continues to be a major problem during repair of obstructed total anomalous pulmonary venous connection (TAPVC) resulting in frequent use of deep hypothermia and low flow bypass. Sutureless technique for primary repair of anomalous pulmonary venous connection is fast becoming popular. In this described modification of sutureless technique through the lateral approach, the left atrium is marsupialized around the common pulmonary venous chamber, except on the right lateral aspect, providing a bloodless field with minimal retraction of heart facilitating the surgery at mild hypothermia. This technique can be particularly useful in small confluence obstructed TAPVC and in mixed TAPVC.

クリッピング困難な脳動脈瘤治療における術中運動誘発電位（MEP）の有用性

The utility of motor evoked potentials (MEPs) for intraoperative neurophysiological monitoring for unclippable complex aneurysms has not been established.The aim of this study was to evaluate and validate the usefulness of intraoperative MEP monitoring in the treatment of complex aneurysms with and without extracranial-intracranial (EC-IC) bypass.From among a group of patients who underwent intraoperative MEP monitoring during surgery for aneurysm, between 2007 and 2014, we retrospectively enrolled 17 consecutive patients with complex aneurysms.Aneurysms were located in the cavernous portion of the internal carotid artery (ICA) in 6, the intracranial portion of the ICA in 6, the anterior cerebral artery in 1, and the vertebral artery in 4 patients. They included 4 large, 7 thrombosed, and 6 dissecting aneurysms. All were treated with parent artery occlusion with or without EC-IC bypass, which included 7 high-flow bypass procedures with radial artery grafting, and 7 low-flow bypass procedures. Of the 17 patients, 6 showed transient or permanent MEP changes. Four of 6 patients showed MEP changes due to temporary occlusion of the recipient artery during bypass construction. However, these changes were reversed by substitution of the recipient artery, intentional hypertension, and shortening of occlusion time. Two patients demonstrated MEP changes when the parent artery was occluded. In one of those two patients, MEP completely disappeared after parent artery trapping, and this remained unchanged until the completion of the surgery without any modification in obliteration of the parent artery. This patient experienced permanent postoperative hemiparesis. The second patient showed significant changes in MEP during temporary ICA occlusion, which however improved after changing the site of occlusion to the common carotid artery (CCA).In conclusion, intraoperative MEP monitoring has a useful role in the treatment of complex aneurysms—in the selection of the safest and most appropriate recipient artery for EC-IC bypass, and choosing the most appropriate point for occlusion of the parent artery.

両側内頚動脈海綿静脈洞部脳動脈瘤に対してバイパス術を併用した母血管閉塞および血管内治療にて両側とも治癒せしめた1例

Aneurysms arising from the intracavernous carotid artery account for 3-5% of all intracranial aneurysms. Bilateral intracavernous carotid artery aneurysms are rare, and there are few reported cases that have been treated surgically. Here, we present the case of a 65-year-old woman with bilateral giant and large aneurysms, who was successfully treated with surgery for bilateral aneurysms. The patient presented with progressive left oculomotor and abducens nerve palsies, and magnetic resonance imaging (MRI) showed bilateral intracavernous mass lesions. Cerebral angiography revealed left giant and right large aneurysms at the intracavernous carotid artery. As a treatment for the symptomatic left aneurysm, balloon test occlusion (BTO) of the left internal carotid artery (ICA) was performed using 15O gas positron emission tomography (PET). The PET study during the BTO showed slightly decreased cerebral blood flow (CBF) in the left hemisphere, without any neurological symptoms. Therefore, left ICA proximal ligation with low-flow bypass was performed. Just after the treatment, thrombosis of the aneurysm began, and the left cranial nerve palsies gradually improved. Three months after the surgery for the left aneurysm, the right aneurysm was treated by using endovascular coil embolization with a stent assist. The postoperative course was uneventful, and the PET study performed 6 months after surgery showed normal CBF, even in the left hemisphere. Bilateral intracavernous carotid artery aneurysms are rare, and surgical treatment is controversial because there is no strict indication for the treatment. However, surgical treatment for patients with progressive symptoms should be considered carefully.

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.

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.

Rapid resolution of brain ischemic hypoxia after cerebral revascularization in moyamoya disease.

In moyamoya disease (MMD), cerebral revascularization is recommended in patients with recurrent or progressive ischemic events and associated reduced cerebral perfusion reserve. Low-flow bypass with or without indirect revascularization is generally the standard surgical treatment. Intraoperative monitoring of cerebral partial pressure of oxygen (PtiO2) with polarographic Clark-type probes in cerebral artery bypass surgery for MMD-induced chronic cerebral ischemia has not yet been described. To describe basal brain tissue oxygenation in MMD patients before revascularization as well as the immediate changes produced by the surgical procedure using intraoperative PtiO2 monitoring. Between October 2011 and January 2013, all patients with a diagnosis of MMD were intraoperatively monitored. Cerebral oxygenation status was analyzed based on the Ptio2/PaO2 ratio. Reference thresholds of PtiO2/PaO2 had been previously defined as below 0.1 for the lower reference threshold (hypoxia) and above 0.35 for the upper reference threshold (hyperoxia). Before STA-MCA bypass, all patients presented a situation of severe tissue hypoxia confirmed by a PtiO2/PaO2 ratio <0.1. After bypass, all patients showed a rapid and sustained increase in PtiO2, which reached normal values (PtiO2/PaO2 ratio between 0.1 and 0.35). One patient showed an initial PtiO2 improvement followed by a decrease due to bypass occlusion. After repeat anastomosis, the patient's PtiO2 increased again and stabilized. Direct anastomosis quickly improves cerebral oxygenation, immediately reducing the risk of ischemic stroke in both pediatric and adult patients. Intraoperative PtiO2 monitoring is a very reliable tool to verify the effectiveness of this revascularization procedure.

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.

Electroencephalographic Evaluation of Cerebral Hyperperfusion Syndrome Following Superficial Temporal Artery-Middle Cerebral Artery Anastomosis

Low-flow bypass, such as superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis, can result in cerebral hyperperfusion syndrome (CHS). The present study evaluated the pathophysiological conditions of CHS through the use of repeated electroencephalography (EEG). Among a total of 22 patients who underwent STA-MCA anastomosis over a course of 4 years, 3 patients were diagnosed with CHS based on clinical symptoms and neuroradiological examinations, including cerebral blood flow evaluation. Case 1 and Case 2 developed CHS on postoperative day 1, when EEG demonstrated focal slow waves on the frontal region of the operated side, indicating cortical dysfunction in these areas. Although prompt recovery of these EEG findings was noted with improvement of the clinical symptoms in Case 1, Case 2 developed an intracranial hemorrhage on postoperative day 5, when EEG clearly depicted persistent nonconvulsive status epilepticus (NCSE) after control of convulsive status epilepticus. In contrast, the clinical onset in Case 3 was delayed to postoperative day 6 and EEG revealed frequent ictal discharges in the operated hemisphere, although convulsive seizures were not apparent. Administration of anticonvulsants was performed after the diagnosis of NCSE, and complete recovery from CHS was achieved. Although the pathophysiology of CHS is cortical dysfunction, ictal hyperperfusion associated with NCSE could be included. The present findings emphasize the importance of repeated EEG examinations in the differential diagnosis of the various types of pathophysiological conditions of CHS.

“Closed-Vein” Technique for Primary Sutureless Repair of Anomalous Pulmonary Venous Connection

Deep hypothermic circulatory arrest or low-flow bypass are commonly used in primary repair of total anomalous pulmonary venous connection, or individual veins may be dissected to allow clamp or snare application, in order to provide a bloodless field for anastomosis by the direct or sutureless marsupialization technique. In the described technical modification, the marsupialization of the opened atrium to the posterior pericardium is completed before opening the pulmonary venous confluence, allowing bloodless exposure during full-flow normothermic bypass. In addition, vein branch dissection is avoided.

Treatment of a cerebral dissecting aneurysm in anterior circulation: report of 11 subarachnoid hemorrhage cases.

This report presents 8 cases of internal carotid artery aneurysms, 1 case of a middle cerebral artery aneurysm, and 2 cases of anterior cerebral artery aneurysms, together with a discussion of the treatment of aneurysms in anterior circulation. All cases showed subarachnoid hemorrhage. Two of the 8 internal carotid artery aneurysms were trapped with a low-flow bypass; however, both patients died of an immediate hemodynamic infarction or vasospasm-induced infarction. Five of the 8 internal carotid artery aneurysms were trapped after revascularization with high flow bypass. Four of those patients were self-supporting at discharge, but one patient was discharged in a vegetative state due to the sacrifice of arterial branches which were included in the dissecting portion. One case of the dissecting aneurysm in the M2 portion of the middle cerebral artery was trapped after low-flow bypass. This patient was self-supporting at discharge. In 2 cases of anterior cerebral artery aneurysms, the lesions were first wrapped with Bemsheets, and then the aneurysmal clip was applied on the wrapped dome. Trapping following high-flow bypass is the best method for treating a dissecting aneurysm in the internal carotid artery. Trapping also can be used to treat a dissecting aneurysm of the middle cerebral artery, after low-flow bypass. Clipping on the wrapped aneurysm can also be performed successfully in the anterior cerebral artery aneurysm.