Yuji Endo

Blood flow disturbance in perforating arteries attributable to aneurysm surgery

OBJECT The object of this study was to investigate patients with cerebral infarction in the area of the perforating arteries after aneurysm surgery. METHODS The authors studied the incidence of cerebral infarction in 1043 patients using computed tomography or magnetic resonance imaging and the affected perforating arteries, clinical symptoms, prognosis, and operative maneuvers resulting in blood flow disturbance. RESULTS Among 46 patients (4.4%) with infarction, the affected perforating arteries were the anterior choroidal artery (AChA) in nine patients, lenticulostriate artery (LSA) in nine patients, hypothalamic artery in two patients, posterior thalamoperforating artery in five patients, perforating artery of the vertebral artery (VA) in three patients, anterior thalamoperforating artery in nine patients, and recurrent artery of Heubner in nine patients. Sequelae persisted in 21 (45.7%) of the 46 patients; 13 (28.3%) had transient symptoms and 12 (26.1%) were asymptomatic. Sequelae developed in all patients with infarctions in perforating arteries in the area of the AChA, hypothalamic artery, or perforating artery of the VA; in four of five patients with posterior thalamoperforating artery involvement; and in two of nine with LSA involvement. The symptoms of anterior thalamoperforating artery infarction or recurrent artery of Heubner infarction were mild and/or transient. The operative maneuvers leading to blood flow disturbance in perforating arteries were aneurysmal neck clipping in 21 patients, temporary occlusion of the parent artery in nine patients, direct injury in seven patients, retraction in five patients, and trapping of the parent artery in four patients. CONCLUSIONS The patency of the perforating artery cannot be determined by intraoperative microscopic inspection. Intraoperative motor evoked potential monitoring contributed to the detection of blood flow disturbance in the territory of the AChA and LSA.

Intraoperative monitoring of visual evoked potential: introduction of a clinically useful method

OBJECT To obtain a clinically useful method of intraoperative monitoring of visual evoked potentials (VEPs), the authors developed a new light-stimulating device and introduced electroretinography (ERG) to ascertain retinal light stimulation after induction of venous anesthesia. METHODS The new stimulating device consists of 16 red light-emitting diodes embedded in a soft silicone disc to avoid deviation of the light axis after frontal scalp-flap reflection. After induction of venous anesthesia with propofol, the authors performed ERG and VEP recording in 100 patients (200 eyes) who were at intraoperative risk for visual impairment. RESULTS Stable ERG and VEP recordings were obtained in 187 eyes. In 12 eyes, stable ERG data were recorded but VEPs could not be obtained, probably because all 12 eyes manifested severe preoperative visual dysfunction. The disappearance of ERG data and VEPs in the 13th eye after frontal scalp-flap reflection suggested technical failure attributable to deviation of the light axis. The criterion for amplitude changes was defined as a 50% increase or decrease in amplitude compared with the control level. In 1 of 187 eyes the authors observed an increase in intraoperative amplitude and postoperative visual function improvement. Of 169 eyes without amplitude changes, 17 manifested improved visual function postoperatively, 150 showed no change, and 2 worsened (1 patient with a temporal tumor developed a slight visual field defect in both eyes). Of 3 eyes with intraoperative VEP deterioration and subsequent recovery upon changing the operative maneuver, 1 improved and 2 exhibited no change. The VEP amplitude decreased without subsequent recovery to 50% of the control level in 14 eyes, and all of these developed various degrees of postoperative deterioration of visual function. CONCLUSIONS With the strategy introduced here it is possible to record intraoperative VEPs in almost all patients except in those with severe visual dysfunction. In some patients, postoperative visual deterioration can be avoided or minimized by intraoperative VEP recording. All patients without an intraoperative decrease in the VEP amplitude were without severe postoperative deterioration in visual function, suggesting that intraoperative VEP monitoring may contribute to prevent postoperative visual dysfunction.

Surgery of acutely ruptured cerebral aneurysms aided by three-dimensional computerized tomography angiography without conventional angiography

Abstract In our previous study, 60 cases of subarachnoid hemorrhage (SAH) from ruptured aneurysms were prospectively evaluated both by three-dimensional computerized tomography angiography (3D-CTA) and conventional catheter angiography (CCA), which resulted in a 100% accuracy for 3D-CTA in the diagnosis of ruptured aneurysms. Based on the results, we assessed whether the aneurysm surgery can be performed on patients with ruptured cerebral aneurysms using 3D-CTA without CCA. 3D-CTA was performed with a helical CT scanner. A total of 123 consequent patients with SAH who had undergone surgery in the acute stage on the basis of 3D-CTA findings were studied. One hundred and twenty-three ruptured aneurysms, including 49 associated unruptured aneurysms, were detected using 3D-CTA. In 7 of 123 ruptured aneurysms, 3D-CTA was followed by CCA to acquire the diagnostic confirmation or the information of the vein. All of the ruptured aneurysms were confirmed at the surgery and treated successfully. One hundred and sixteen patients who underwent the operation with the use of 3D-CTA only had no complications related to the lack of CCA information. 3D-CTA provided us with aneurysm location as well as the surgically important information on the configuration of its sac and neck, and its relationship to adjacent vessels and bone structures. 3D-CTA can replace CCA in the diagnosis of ruptured aneurysms and acute surgery can be performed in almost all acutely ruptured aneurysms by using only 3D-CTA without CCA.

Prevention of symptomatic vasospasm — effect of continuous cisternal irrigation with urokinase and ascorbic acid

Background Continuous cisternal irrigation (CCI) with urokinase (UK) and ascorbic acid (AsA) has been performed to prevent symptomatic vasospasm (SVS) after severe aneurysmal subarachnoid haemorrhage (SAH). To dissolve and wash out the SAH, CCI with urokinase is used. Ascorbic acid is added to degrade oxyhemoglobin, one of the strong spasmogenic substances. The efficacy and safety of this method were evaluated.

The surgery of ruptured and unruptured cerebral aneurysms using three-dimensional CT angiography without conventional catheter angiography

Abstract The object of this study is to assess whether aneurysm surgery can be performed in patients with ruptured and unruptured cerebral aneurysms by using three-dimensional computerized tomography angiography (3D-CTA) alone, without conventional catheter angiography (CCA). We have operated on 153 consecutive patients with ruptured aneurysms and 89 patients with unruptured aneurysms based on 3D-CTA findings since December 1996 and February 1997, respectively. In the cases of ruptured aneurysm, 153 ruptured aneurysms including 62 associated unruptured aneurysms were detected by 3D-CTA. CCA was performed in 7 of 153 patients after they underwent 3D-CTA, which included four dissecting vertebral artery (VA) aneurysms, two basilar artery (BA) tip aneurysms, and one BA–superior cerebellar artery (SCA) aneurysm. In 89 patients with unruptured aneurysms, 101 unruptured aneurysms were detected by 3D-CTA. In 5 of 101 unruptured aneurysms, which included giant or large aneurysms and a case of an aneurysm associated with infarction, CCA was needed. All of the ruptured and unruptured aneurysms were confirmed during surgery and treated successfully. The authors stress that 3D-CTA could replace CCA in the diagnosis of saccular aneurysms and that surgery could be performed in almost all ruptured and unruptured aneurysms by using only 3D-CTA without CCA.