Outcome in 60 consecutive patients treated with early aneurysm operation and intravenous nimodipine

Sixty consecutive patients with a ruptured supratentorial aneurysm underwent operation during the acute stage, 56 of them within 72 hours after the first bleed, one on the 4th day, and three on the 5th day. Six patients were classified preoperatively in Hunt and Hess neurological Grade I, 39 in Grade II, 11 in Grade III, and four in Grade IV or V. Nine patients had severe intracerebral hematomas, and one patient had a subdural hematoma. After the aneurysm was clipped, nimodipine was applied to the exposed arterial segments in a 2.5 X 10(-5)M solution for 10 minutes. Subsequently, all patients received a continuous intravenous nimodipine infusion (2 mg/hr) for 7 to 12 days, followed by oral treatment (270 mg/day). Forty-six patients (77%) made a good neurological recovery; the morbidity rate was 22%, and mortality rate 1.5%. Of the 45 patients in good condition (Grades I to II) preoperatively, 38 (84%) made a good neurological recovery. Two patients (3% of the total series) developed a typical picture of cerebral ischemic dysfunction of delayed onset with subsequent fixed neurological deficits. The results favor the opinion that early operative intervention is beneficial in patients in good condition rather than delaying surgery, and indicate that nimodipine provides an additional anti-ischemic effect. The appearance and severity of late angiographic vasospasm did not seem to be affected by nimodipine.     

Surgical approach to giant intracranial aneurysms. Operative experience with 80 cases.

The authors report experience with the surgical management of 80 giant intracranial aneurysms (greater than 2.5 cm in diameter) during a 10-year period in which they performed 594 operations for aneurysms. The overall incidence of giant aneurysms was 13% but varied according to location: 20% of aneurysms of the internal carotid artery (ICA); 13% of middle cerebral artery (MCA) aneurysms; 1% of anterior cerebral artery (ACA) aneurysms; 15% of aneurysms of the basilar artery caput (BAC); and 18% of vertebrobasilar trunk (VB) aneurysms. Twenty-five patients had a subarachnoid hemorrhage (SAH), 49 had mass effect from the aneurysm, and six had ischemic events. There was no apparent difference in results related to the presence or absence of an SAH. Poor results were attributable to the operation except in the two cases of ACA aneurysm in which preexisting dementia persisted. Mortality was 4% and morbidity was 14%, varying from a combined low morbidity-mortality of 8% for ICA lesions to a high to 50% for BAC aneurysms. During the period of the study, different techniques were developed in an attempt to lower the risks of surgery. Ultimately ICA aneurysms were monitored with cerebral blood flow measurements and electroencephalography before and after temporary ICA ligation, then approached following resection of the anterior clinoid or treated with bypass in combination with ICA ligation. Aneurysms of the MCA were either opened during temporary MCA occlusion or resected in combination with a bypass procedure. Bypass grafts and circulatory arrest with extracorporeal circulation may have a role in giant aneurysms of the posterior circulation.     

Ruptured cerebral aneurysm of the median artery of the corpus callosum (accessory anterior cerebral artery): case report

A rare case of ruptured cerebral aneurysm of median artery of corpus callosum (accessory anterior cerebral artery: Acc ACA) is reported. A 66-year-old hypertensive female suddenly lost consciousness for 5 minutes and later complained of severe headache. On admission, the next day, consciousness was clear and she showed no neurological deficit except for right motor weakness. CT scan revealed subarachnoid hemorrhage, and carotid angiography showed triplicated anterior cerebral artery with a saccular aneurysm on the Acc ACA. Twenty hours after the onset, an operation was performed to clip the aneurysm neck. Post-operative course was uneventful and she was discharged on the 25th postoperative day without neurological deficits. When the median artery of corpus callosum(MACC), a branch of anterior communicating artery distributes to one or to both hemispheres, it is called Acc ACA. It is thought to be a vascular anomaly and which has an incidence of 20%. However, cases of aneurysm of MACC (or Acc ACA) have not been reported and our case is considered to be the first.     

Nimodipine and early aneurysm operation in good condition SAH patients

A prospective open multicenter study on the preventive effect of nimodipine on symptomatic vascular spasm was performed in 120 (consecutive) patients with aneurysmal subarachnoid haemorrhage (SAH). All patients underwent early surgery (i.e. within 72 hours post SAH) and were in neurological grades I-III in Hunt and Hess. Grade IV and V as well as patients with significant intracerebral haematoma are not included. On preoperative CT, SAH was mild in 28 cases, moderate in 56 and severe in 36 cases. 25 patients (21%) were in grade I, 63 patients (53%) in grade II and 32 patients (26%) in grade III. The ruptured aneurysm was located on the anterior cerebral artery complex in 57 patients, on the internal carotid artery complex in 35, on the middle cerebral artery in 24 patients and on the basilar artery in 4 patients. After occlusion of the ruptured aneurysm, the lipophilic calcium channel blocker nimodipine was administered in the following manner: Intraoperative, topical irrigation of the exposed arteries. Intravenous infusion until day 7-14 after SAH followed by peroral medication for another week. Nimodipine was well tolerated and neither significant hypotension nor any other adverse reaction attributable to the drug was observed. Ischaemic cerebral dysfunction of delayed onset with permanent neurological deficit occurred in 2 patients (2%). Another 8 patients showed transient ischaemic symptoms. At 6 months follow-up, 93% of the patients were classified as having made a full recovery, 16% as being minimally disabled, 5% as being moderately disabled and 3% as being severely disabled. Three patients had died. The present study supports the concept that preventive nimodipine treatment may reduce delayed ischaemic deficit in early aneurysm surgery.     

Intracerebral hematomas caused by aneurysm rupture. Experience with 67 cases

During a six-year period (1986–1992) 334 patients with subarachnoid hemorrhage (SAH) were admitted to the Department of Neurosurgery, Medical University of Lübeck, Germany. In 281 patients the SAH was caused by rupture of an intracranial arterial aneurysm, verified by angiography, postmortem examination, or at emergency operation without angiography. In 67 (23.8 %) of the 281 aneurysmal SAH patients the initial computerized tomography (CT) demonstrated an intracerebral hematoma (ICH). An ICH localized in the temporal lobe due to the rupture of a middle cerebral artery (MCA) aneurysm was found in 47 patients (70.2 %). Forty-three patients were considered for surgery with a surgical mortality of 8 (18.6 %). In the group of 19 ICH patients not operated upon, 16 individuals died (84.2%).We therefore advocate active surgical management of ICH patients: hematoma evacuation and aneurysm clipping at the same operation. Emergency surgery in younger patients (grade V) with temporal ICH suggesting the rupture of a MCA or internal carotid artery (ICA) aneurysm can be done without angiography.     

Middle cerebral-anterior cerebral-radial artery interposition graft bypass for proximal anterior cerebral artery aneurysm

A 74-year-old man underwent pterional craniotomy to treat a left proximal anterior cerebral artery (ACA) aneurysm. The orifice of the aneurysm was located at the origin of the proximal segment of the ACA, and the right A(1) segment of ACA was hypoplastic. After failed attempts at neck plasty with fenestrated clips, trapping and bypass were performed. Superficial temporal to left frontopolar artery bypass was performed to secure minimal blood supply. The radial artery (RA) was then harvested, and middle cerebral artery (MCA) to A(1) segment of the ACA bypass was performed using the RA interposition graft. Trapping of the aneurysm was successfully achieved without ischemic event. Intracranial-intracranial bypass has been employed in the treatment of complex cerebral aneurysm in an increasing number of selected patients. The present case shows that MCA-ACA-RA interposition graft bypass is an effective procedure to provide blood supply to the ACA territory if a proximal A(1) lesion requires trapping with incompetent contralateral A(1).     

Double-insurance bypass for internal carotid artery aneurysm surgery

OBJECTIVE: The aim of this article is to present the usefulness of a double-bypass method in the surgical treatment of complex internal carotid artery (ICA) aneurysms. For patients with clippable but complex aneurysms of the ICA having poor collateral circulation, bypass surgery is needed before temporary occlusion of the ICA. We propose a double bypass for safety. METHODS: The superficial temporal artery was anastomosed to the distal cortical branch of the middle cerebral artery (MCA), followed by anastomosis between the radial artery and the inferior trunk of the MCA. For patients with clippable ICA aneurysms, the radial artery was temporarily anastomosed to the inferior trunk of the MCA by raising the ipsilateral forearm to the head after the radial artery was harvested. After the aneurysm had been clipped, the anastomosed radial artery was cut close to the anastomosed site and repositioned back to the original arm. RESULTS: This double-bypass procedure was performed in two patients, and no ischemic complications related to revascularization were observed. Temporary occlusion times of the MCA for superficial temporal artery-to-MCA anastomosis and radial artery-to-MCA anastomosis were 30 and 46 minutes in one patient and 28 and 55 minutes in another. CONCLUSION: This surgical procedure, which we called "double-insurance bypass," can reduce the risk of ischemic complications associated with revascularization of the ICA.     

Endovascular Treatment of Aneurysmal Subarachnoid Hemorrhage in Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2

To distinguish the characteristics of ruptured cerebral aneurysm that are suitable for endovascular treatment from those that are not, we evaluated factors that influenced the results of aneurysm embolization in patients with ruptured cerebral aneurysm, based on data from the Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2. The multivariate analysis revealed that young patients, patients with low modified Rankin Scale (mRS) scores before onset, and patients with low World Federation of Neurosurgical Societies (WFNS) grades had good outcome. Compared to proximal internal carotid artery (ICA) aneurysms, the odds ratio of middle cerebral artery (MCA) aneurysms was 1.67, indicating poorer outcome for MCA aneurysms, and patients with small, wide-neck cerebral aneurysms had poor outcome. Patients treated after 15 days had better outcome than during other periods. The timing of treatment, however, did not influence the outcome in patients treated within 14 days. The outcome was poorer when the responsible doctor for the treatment was a specialist or a non-specialist than a supervisory doctor. The outcome of patients treated with bare platinum coils, and three dimensional (3D) rotational angiography was better, and the outcome of patients who completed treatment with body filling was poorer than in patients with complete occlusion. Perioperative hemorrhagic complications, all ischemic complications, and rebleeding occurred in 4.5%, 6.4%, and 1.4% of patients, respectively. All these complications had poor outcome factors on day 30, with odds ratios of 2.72, 2.96, and 25.49, respectively. We must be fully aware of these risk factors and determine indications for the treatment when endovascular treatment is performed as the treatment of choice for ruptured cerebral aneurysm.     

无蛛网膜下腔出血的大脑中动脉动脉瘤破裂

目的总结无蛛网膜下腔出血（SAH）的大脑中动脉（MCA）动脉瘤破裂的临床特点。方法对6例在首次CT扫描上表现为脑内出血（ICH），或壁内出血（IMH）而无SAH的MCA动脉瘤破裂患者的临床表现、影像学检查、治疗方法和预后进行回顾性总结。结果本组首次CT扫描时间为起病后0—2d，表现为单纯ICH者4例，IMH者2例。DSA和手术证实为MCA动脉瘤破裂。开颅动脉瘤切除1例，夹闭5例，其中4例同时行血肿清除术。术后无死亡。结论MCA动脉瘤破裂首次CT扫描可仅表现为ICH或IMH而无SAH，与动脉瘤的部位、出血量以及CT扫描时间相关。     

Observation of de novo formation and growth of an intracranial aneurysm: a case report

We observed a de novo formation and growth of an aneurysm in a 43-year-old woman who was followed up after treatment of a subarachnoid hemorrhage (SAH). In 2002, the patient, whose mother had a history of SAH, presented with SAH at the age of 36. Three-dimensional computed tomography angiography (3D-CTA) and digital subtraction angiography showed an aneurysm in the right internal carotid-posterior communicating artery. The aneurysm was clipped and postoperative course was uneventful without neurological deficit. The patient was followed up by 3D-CTA and magnetic resonance angiography every 6 months, because of an untreated small aneurysm, 3 mm in diameter, in the left middle cerebral artery (MCA). The MCA aneurysm remained unchanged but a de novo aneurysm, 1.5 mm in diameter, developed in the right anterior cerebral artery (ACA) 6 years after the first surgery. The ACA aneurysm grew to 4 mm in diameter during the following 10 months but the MCA aneurysm remained unchanged. Both aneurysms were clipped in one session. The MCA aneurysm had a smooth wall but the ACA aneurysm had an irregular and thin wall. The postoperative course was uneventful. Young female patients who have developed SAH with familial history, like this case, should receive long-term follow up to check whether a de novo aneurysm has developed.     

Subdural hematoma due to ruptured intracranial aneurysm.

Subdural hematoma (SDH) was observed in 15 of 484 cases of aneurysmal subarachnoid hemorrhage (SAH). There were four males and 11 females, with ages ranging from 39 to 75 years. The clinical grades (Hunt and Hess) on admission were 11 in three cases, III in two, IV in four, and V in six. The ruptured aneurysms were located in the middle cerebral artery (MCA) in six cases, anterior communicating artery in three, internal carotid artery in two, and distal anterior cerebral artery (ACA) in two, with two cases unconfirmed. A high proportion of aneurysms occurred in the MCA and distal ACA. Aneurysmal neck clipping and removal of SDH were performed in the acute stage of seven cases, without intraoperative rerupture. The outcomes 1 year after SAH of the seven patients undergoing surgery were good recovery in five, but in two, vegetative state due to preoperative rerupture or medical complications. All eight patients without surgical intervention died. A good prognosis for patients with ruptured intracranial aneurysms accompanied by SDH can be expected with direct surgical intervention in the acute stage, even if the clinical grade on admission is poor.     

Thrombosed unruptured cerebral aneurysm causing brain infarction followed by subarachnoid hemorrhage--case report--

A 71-year-old man presented with right hemiparesis and aphasia due to cerebral infarction in the frontal lobe. Computed tomography (CT) revealed a high-density mass, 12 mm in diameter, in the stem of the left sylvian fissure. Carotid angiography demonstrated occlusion of the left ascending frontal artery complex and retention of contrast medium at the bifurcation of the left middle cerebral artery (MCA). The diagnosis was cerebral infarction caused by occlusion of the ascending frontal artery complex resulting from thrombosed left MCA aneurysm. The patient was managed conservatively and his neurological symptoms gradually improved. One month later, he lapsed into a coma. CT revealed subarachnoid hemorrhage. Carotid angiography showed a large left MCA aneurysm with branch occlusion of the left ascending frontal artery complex. A left frontotemporal craniotomy was performed. The MCA aneurysm was opened and the intramural thrombi removed, and finally neck clipping was performed. The patient made a good postoperative recovery.     

Treatment of ruptured intracranial aneurysms: our approach.

OBJECTIVE: Subarachnoid hemorrhage (SAH) often results in devastating neurological deficits requiring hospitalization and loss of independence. This is often a difficult time for patients and their families who are struggling to cope with this sudden illness. Current treatment options include surgical clipping of the aneurysm or endovascular obliteration using Guglielmi detachable coils. Our purpose in writing this paper was to review the factors that determine the choice of treatment. In addition to this we wanted to study the benefits of surgical clipping for ruptured aneurysms over endovascular coiling. MATERIAL AND METHODS: We studied--retrospectively--450 cases of ruptured cerebral aneurysms admitted to our institution from 1997 to 2003. Out of these, 324 were subjected to surgical clipping and 126 to endovascular techniques. The outcome was studied using the Glasgow Outcome Score (GOS). RESULTS: Of the 324 cases of surgical clipping 222 had a good recovery, 38 had moderate disability, 15 had severe disability, 13 became vegetative and 36 patients died. In the endovascular group 34 had a good recovery, 22 had moderate disability, 18 had severe disability, 15 became vegetative and 37 patients died. Grade to Outcome was compared for both forms of treatment. In our series clipping for ruptured aneurysm was preferred to coiling in fusiform-shaped aneurysms, large or giant aneurysms, MCA aneurysms, blister aneurysms, complex configurations, partially thrombosed aneurysms and aneurysms associated with cerebral hemorrhage. Coiling was performed for basilar tip and trunk aneurysms, high anterior communicating artery aneurysms, patients in subacute stages of subarachnoid hemorrhage, and those with associated medical complications. CONCLUSION: Based on this study we were able to formulate a few definite indications for clipping, even in the times of advanced endovascular techniques. In addition we could also prove the benefits of surgical clipping over the endovascular technique in severe subarachnoid hemorrhage.     

Characteristics of aneurysms of the internal carotid artery bifurcation

Summary Background. Arterial bifurcations are sites of maximal hemodynamic stress, where cerebral aneurysms commonly develop. However, in our experience with endovascular treatment for aneurysms of the internal carotid artery (ICA) bifurcation, we often experienced that the aneurysmal neck did not necessarily exist only at the ICA bifurcation (ICBi). In this study, we have retrospectively evaluated characteristics of aneurysms at the ICBi. Methods. Ten ICBi aneurysms in 10 consecutive patients were studied retrospectively. The size of the aneurysms, the angles formed between the ICA and the anterior cerebral artery (ACA) and middle cerebral artery (MCA), and the diameter of the ICA, ACA and MCA were measured. Furthermore, to study the relationship between the location of the aneurysmal neck and the bifurcation of the ICA, the distance between the midline of the aneurysmal neck and of the ICA was measured. Results. The average aneurysm size was 6.3 ± 3.2 mm and the average neck was 3.1 ± 1.2 mm. The average ICA-ACA angle was 57.3 ± 16.5 degrees, and the average ICA-MCA angle was 128.9 ± 24.1 degrees. The average diameters of the ICA, ACA and MCA were 2.9 ± 0.5 mm, 1.9 ± 0.4 mm and 2.5 ± 0.4 mm, respectively. The average distance between the midline of the aneurysmal neck and the ICA was 1.6 ± 0.6 mm, and all aneurysmal necks of the ICBi arose from the side of the ACA. Conclusion. ICBi aneurysms were deviated to the side of the A1 segment of the ACA, where the artery might suffer higher hemodynamic stress.     

Ruptured middle cerebral artery aneurysm with intracerebral hemorrhage in younger patients appearing moribund: emergency operation?

Four women, aged 39 to 46 years, were urgently admitted to our neurosurgical unit after strokes. On admission, all appeared moribund, presenting with deep coma, pupils bilaterally dilated and fixed, decerebrate posture, and markedly abnormal respiratory patterns. Computed tomography revealed subarachnoid hemorrhage with an associated large intracerebral hematoma and pronounced shift of midline structures in all four cases. Because of the clinical appearance, the patients were given urea and were operated without preceding angiography. The origin of the hemorrhage was identified as a middle cerebral artery (MCA) bifurcation berry aneurysm in one patient and giant MCA aneurysms in the other three. The hematomas were evacuated, and the aneurysms were occluded. All four patients received intravenous nimodipine, none showed any sign of delayed ischemic deterioration, and all regained full consciousness within a few days. One patient died 3 weeks later from a pulmonary embolus. Three patients are presently at home with moderate focal neurological deficits and moderate to marked cognitive impairment. The psychosocial readjustment was very good in a patient with a left giant aneurysm, satisfactory in a patient with a right giant aneurysm, and unsatisfactory in a patient with a right berry aneurysm. The indications, ethical considerations, and technical aspects of operating on seemingly moribund patients who probably harbor a ruptured MCA aneurysm are discussed.     

Tailored flow sequestration treatment using high-flow and low-flow bypass for partially thrombosed giant internal carotid artery aneurysm—a technical case report

Direct clipping of giant partially thrombosed intracranial internal carotid artery (ICA) aneurysms is challenging, especially when important perforating arteries are involved. Proximal occlusion with bypass represents a possible alternative approach. An 80-year-old female presented with worsening visual acuity and severe headache caused by partially thrombosed giant (38 mm in diameter) aneurysms of the right ICA, suggestive of impending rupture. Direct clipping in conjunction with temporary occlusion of the lesion involving the anterior choroidal artery (AChA) was considered too risky. Thus, we sequestrated the ipsilateral ICA flow into a low-flow and a high-flow system using two external carotid artery (ECA)-ICA bypasses and one in situ bypass with cervical ICA ligation. As a result, the low-flow system by the superficial temporal artery-middle cerebral artery (MCA) bypass perfused mainly the proximal MCA lesions and aneurysm, whereas the high-flow system by ECA-radial artery-M2 bypass exclusively supplied the residual distal MCA area. This tailored flow sequestration successfully interrupted intra-aneurysmal flow and accelerated near-complete thrombosis of the aneurysm while preserving the AChA and avoiding any significant neurological deterioration. We conclude that this method is effective for the management of giant partially thrombosed aneurysms of the ICA, especially when direct clipping is difficult.     

Regional cerebral blood flow (rCBF) in patients with ruptured cerebral aneurysm: site of aneurysm and rCBF

To investigate the relationship between the site of ruptured cerebral aneurysm and rCBF, 92 measurements of rCBF were conducted in 57 patients with ruptured cerebral aneurysm. Excluded from this study were patients with multiple aneurysms, intracerebral hematoma, and/or hydrocephalus. Twenty-four patients had the anterior communicating aneurysm (A-com), 20 patients had the internal carotid aneurysm (ICA), and 13 patients had the middle cerebral aneurysm (MCA). All patients underwent unilateral fronto-temporal craniotomy for clipping of the aneurysm and their rCBF measurements, using the xenon-133 inhalation method, were performed in the first three weeks after surgery. In each rCBF measurement, the hemispheric mean value of initial slope index (meanISI) was calculated in both cerebral hemispheres, that is, in the cerebral hemispheres ipsilateral and contralateral to craniotomy. The authors defined the "symmetry index of the meanISI (%): symmetry index" as the ratio of the meanISI in the cerebral hemisphere ipsilateral to craniotomy compared to the meanISI in the cerebral hemisphere contralateral to craniotomy. There was no significant relationship between the site of aneurysm and the meanISI in both hemispheres, and this result suggests that the site of aneurysm makes no difference in the incidence of vasospasm. In the postoperative first week, the "symmetry index" was 91.2 +/- 7.4% in MCA, 95.3 +/- 4.1% in ICA, and 97.9 +/- 8.2% in A-com; that is, MCA had significant asymmetry of meanCBF compared with A-com (p less than 0.05). In the second and third postoperative weeks, there was no significant relationship between the site of aneurysm and the asymmetry of meanCBF.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intentional partial coil occlusion followed by delayed clip application to wide-necked middle cerebral artery aneurysms in patients presenting with severe vasospasm. Report of two cases

The treatment of ruptured cerebral aneurysms in patients presenting with vasospasm remains a particular challenge. The authors treated two patients harboring Hunt and Hess Grade 1 subarachnoid hemorrhages from middle cerebral artery (MCA) aneurysms associated with severe local angiographically demonstrated yet asymptomatic vasospasm on presentation. Because both aneurysms had wide necks and were located at the MCA bifurcation, they were believed to be anatomically suitable for microsurgical clip application. Severe M, vasospasm was believed to be a relative contraindication to open surgery, however. An intentionally staged endovascular and microsurgical treatment strategy was planned in each patient. Partial coil occlusion of the aneurysmal dome was performed to prevent the lesion from rebleeding and was followed by balloon angioplasty of the spastic vessel. Early treatment of the severe spasm appeared to prevent significant delayed neurological ischemic deficit. Following resolution of the vasospasm, definitive clipping of the aneurysms was performed on Day 13 post embolization. One patient had a good clinical recovery and was discharged without neurological deficit. The other patient's hospital course was complicated by the occurrence of a postoperative posterior temporal infarct requiring partial temporal lobectomy, although she eventually had a good recovery with only a small visual field deficit. Based on data obtained in these two patients, one can infer that ruptured wide-necked MCA aneurysms associated with severe local vasospasm may best be treated using a staged combined treatment plan. Delayed clip application might be performed more safely 4 to 6 weeks postocclusion, or later, than at 2 weeks.     

Somatosensory evoked potential monitoring of temporary middle cerebral artery occlusion during aneurysm operation

Somatosensory evoked potentials (SEPs) in response to median nerve stimulation were used as a guide to cortical function during temporary occlusion of the distal M1 segment of the middle cerebral artery (MCA) in the surgical treatment of five large aneurysms of the MCA bifurcation. MCA occlusion times ranged from 8 to 19 minutes under moderate hypothermia at 28.8 degrees to 30.3 degrees C. SEPs were preserved for variable times during MCA occlusion, ranging from no increase in latency after 13 minutes of occlusion to severe deterioration after 6 minutes. In no case was MCA occlusion maintained for longer than 3 minutes in the presence of a severely disturbed SEP. Recovery of the SEP to its preoperative relationship with that of the nonoperated hemisphere was seen in all cases before the end of operation. All patients were awake after rewarming at the end of operation without any neurological deficit. Monitoring the SEP pertaining to the territory of a cerebral artery during its temporary occlusion can help avoid ischemic damage and will allow the surgeon to take advantage of the several benefits of this technique in aneurysm surgery.