Randomized clinical trials have proved that carotid endarterectomy prevents cerebral ischemic events. A low complication rate is, however, an indispensable prerequisite for effectiveness of the surgery. In this article, we offer tips and pitfalls of carotid endarterectomy, especially for inexperienced neurosurgeons.

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We retrospectively examined both the incidence of newly detected hyperintense areas using diffusion-weighted MR images (DWI-HIA) and postoperative complications after carotid endarterectomy (CEA) for patients with high cervical internal carotid artery (ICA) stenosis. Among 39 patients who underwent CEA between January 2001 and October 2006, 10 showed high cervical ICA stenosis on the preoperative carotid angiogram. CEA was successfully performed on 9 patients with oral intubation and 1 patient with nasal intubation under general anesthesia. Transient hypoglossal nerve palsy was seen in 1 patient and wound hematoma in 1 patient. Mortality and morbidity were zero at 1 month after CEA. In 3 of 10 patients (30%), asymptomatic small DWI-HIAs were detected postoperatively.
Gentle manipulation of the internal carotid artery is essential for high cervical carotid artery stenosis to prevent embolic complication after CEA.

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We investigated the usefulness of the posterior tibial nerve somatosensory evoked potentials (PTN-SEP) for detecting the cerebral blood flow insufficiency of the anterior cerebral artery (ACA) during anterior communicating (Acom) or distal ACA aneurysm surgery. PTN-SEP monitoring was employed in 112 patients of Acom and 23 patients of distal ACA aneurysm. After dural incision, control data were recorded, and a decrease of more than 50% in the amplitude of P37-N45 was defined as significant. We evaluated the intraoperative PTN-SEP findings, causes of PTN-SEP change, and motor outcomes in the lower extremities. PTN-SEP changes were observed in 21 patients.
The causes of SEP change were thought to be attributable to blood flow insufficiency with aneurysmal bleeding, with or without temporary occlusion on the ACA in 10 patients. In the other 10 patients, the cause was intensive temporary occlusion. In the last patient, inappropriate clipping on the parent artery was the cause of SEP change. No obvious difference was observed between bilateral and unilateral ACA occlusion. Following the release of the occlusion and repositioning of the clip, PTN-SEP was recovered to the control value in all but 1 patient. Of these 21 patients, 11 did not show any postoperative motor paresis of the lower extremity; transient motor paresis was recognized in 10 patients.
Despite the large variability of territories of the ACA and collateral circulation via the leptomeninges, intraoperative PTN-SEP monitoring was helpful in the operative maneuver, such as ACA occlusion.

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Before the PiCCO system became available, patients with delayed vasospasm were treated in order to control circulating blood volume from the viewpoint of several systemic factors associated with pressure such as central venous pressure, pulmonary arterial wedged pressure, etc. Since, however, these factors are well-known to not always reflect the circulating blood volume, excessive intravenous administration induces over-hydration in patients who are either aged and/or are experiencing symptomatic vasospasm, leading to serious conditions such as pulmonary edema and cardiac failure. The PiCCO system has enabled us to treat patients with symptomatic vasospasm by more precisely estimating circulating hemodynamics. Taking into account the data obtained from the PiCCO system, we discuss its advantages and disadvantages. Out of patients who underwent acute surgery from June 2006 to May 2007, a total of 18 patients with Fisher 3 in CT grading of SAH who were thought to be likely to suffer from cardiac failure or pulmonary edema were selected. The average age was 63.2. The number of patients of preoperative Hunt and Kosnik Grade II, III, IV and V was 3, 10, 3 and 2, respectively. Angiographic vasospasm was revealed in 10 patients, 7 of whom were symptomatic. The in- and out-put control in these 18 patients was executed using the PiCCO system. None showed clinical symptoms associated with cardiac failure or pulmonary edema.
We conclude that the PiCCO system is very useful to control the systemic hemodynamics in the treatment of patients with delayed vasospasm.

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We experienced STA-MCA anastomoses with 4 symptomatic patients with near occlusion of the internal carotid artery (ICA) who demonstrated hemodynamic ischemia confirmed by cerebral blood flow (CBF) measurement. Although we had usually performed carotid endarterectomy (CEA) for patients with near occlusion of the ICA, we performed STA-MCA anastomosis for these patients. The reasons for performing STA-MCA anastomoses were difficulties of CEA due to highly positioned stenosis and high risk of hyperperfusion after CEA because of preoperative hemodynamic ischemia. There were no perioperative complications or restrokes during follow-up (from 6 months to 5 years and 1 month).
Evaluation of the CBF of these patients after CEA showed improvement in both resting CBF and cerebral vascular reactivity.
Therefore, STA-MCA anastomosis may be effective for the patient with near occlusion of the internal carotid artery (ICA) who has a high risk of CEA and hemodynamic ischemia.

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The management of patients with unruptured intracranial aneurysms (UIAs) is controversial. We aimed to assess the natural history of UIAs and evaluate the surgical results. We analyzed 154 patients (181 saccular UIAs) with no history of subarachnoid hemorrhage (SAH) from a different aneurysm. Aneurysms were detected by magnetic resonance angiography (MRA) or by 3-dimensional CT angiography. Although the most frequent reason for the diagnosis was routine brain examinations of healthy patients or a vague symptom such as headache or dizziness, 15 patients were symptomatic. The natural history in patients who did not have surgery (follow-up group: 76 cases, 95 aneurysms) was assessed, and the surgical outcome of UIAs (surgical group: 78 cases, 86 aneurysms) was evaluated. Among 76 patients in the follow-up group, 7 had SAH. The mean latency period to aneurysm rupture was 3.2 months. The aneurysms with subsequent bleeding ranged from 5 to 25 mm (19.3 mm on average), whereas those without ranged from 1 to 28 mm (4.5 mm on average). The rupture rates of UIAs in anterior and posterior circulation were 6.2% and 14.3%, respectively. All ruptured cases were females. Mortality and morbidity associated with UIAs in the follow-up group were 3.9% and 3.9%, respectively. In the surgical group, no mortality was noted. Permanent morbidity associated with prospective repair of UIAs was 5.1%, although the morbidity of the patients with preoperative Rankin scores of 0 or 1 was 1.3%. Transient morbidity was observed in 6 patients (7.7%) with the size of the aneurysm 19.8 mm on average. The natural history and surgical results in patients with UIAs are modified by several factors including aneurysm size and location, the patient's age and gender, the medical status and the patient's preoperative Rankin score.
The present results indicated that these factors should be considered in deciding whether to treat UIAs, and that careful assessment of the surgical benefits might be essential especially in the cases of larger aneurysm size (more than 15 mm) because they are associated either with a greater risk of rupture or with a higher surgical risk.

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The efficacy of a superficial temporal artery (STA)—middle cerebral artery (MCA) anastomosis for patients with poor cerebral blood flow (CBF) and severe decrease of cerebral vascular reserve (CVR) has been recently proved in a Japanese EC-IC bypass trial study. However, we have little clinical knowledge or evidence regarding how to increase CBF or how to evade ischemic risk when performing this surgery. We examined the size and the number of the donor arteries and the location of the recipient artery to retrospectively determine the difference of increase on CBF and CVR by their methods.
The objects were 34 patients with preoperative misery perfusion of low rCBF and poor rCVR. Both were evaluated preoperatively, immediately after operation, and at least 3 weeks after operation with N-isopropyl-p-[¹²³I] iodoamphetamine. The patients were divided into groups based on the number of the donor arteries or the location of the recipient artery and statistically compared.
Postoperative rCVRs increased dramatically from preoperative rCVRs, compared with a small increase of rCBF. Single bypass showed an increase of rCBF and rCVR similar to that of double bypass. Selection of the recipient artery in the sylvian fissure showed significantly more increase of rCVR.
Double bypass with selection of the larger recipient artery was most effective for improving misery perfusion.

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Dramatic recovery after intravenous t-PA therapy may be associated with early recanalization of the occluded vessel. On the contrary, no clinical improvement may indicate persistent occlusion, and clinical aggravation may result from untimely re-perfusion, causing irreversible brain damage because of severe ischemia.
Diffusion-weighted magnetic resonance imaging (DWI) was useful to determine the early ischemic change by main artery occlusion, and the DWI/PWI mismatch was helpful to decide the indication of intravenous t-PA therapy.
Digital subtraction angiography was performed to evaluate recanalization of the occluded artery after intravenous t-PA therapy. Percutaneous transluminal angioplasty was useful if the arterial occlusion had persisted.
Ten cases of this protocol show good outcome and no hemorrhagic complications. It is important to ensure early re-perfusion of the undamaged brain (penumbra).

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Surgery of direct neck clipping of basilar tip aneurysms is one of the most challenging procedures in vascular neurosurgery, as these lesions are deeply situated in the interpeduncular region and maintain an intimate relationship with important anatomical structures. So aneurysms of this location are now frequently treated with endovascular technique. Microsurgical clipping occlusion technique still, however, maintains its solid position because of its completeness. We suggest the transsylvian approach for aneurysms of this location.
There are several tactics to improve operative results. A wider surgical field can be obtained by dissecting the sylvian fissure from the distal segment. And anterior clinoidectomy and unroofing of the optic canal widen the space around the internal carotid artery and its cisternal cavity. Transection of the posterior communicating artery is needed in particular cases.
The temporary clipping method and intensive hypotension are useful for dissecting perforating arteries and ensuring complete neck clipping.

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Insufficient exposure at the distal site of the internal carotid artery is often encountered in carotid endarterectomy, especially when the lesion is high beyond the second vertebral body (C2) or atheromatus thickened intima continue to the far distal region. Previously reported fixative materials like strings or clips restrict the operative field in such cases.
We conducted a new fixative method of internal carotid shunt at the distal internal carotid artery in carotid endarterectomy. We prepared a Sugita fenestrated clip, silicone tube used in CSF shunt and an internal shunt. A Pruitt-Ihanara carotid internal shunt is fixed in the usual manner using the tape at the common carotid artery but is fixed by the prepared Sugita clip from the proximal side at the distal internal carotid artery.
This method provides at least 10-15 mm far distal operative field. In addition, the distal flap can be easily stripped or sutured.

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