Statistical evaluation of individual external exposure dose of outdoor worker and ambient dose rate at evacuation ordered zones after the Fukushima Daiichi nuclear power station accident.

Following the accident at the Fukushima Daiichi Nuclear Power Station, evacuation orders were issued for the surrounding communities. In order to lift the evacuation order, it is necessary to determine individual external doses in the evacuated areas. The purpose of this study was to determine the quantitative relationship between individual external doses and ambient dose rates per hour as conversion coefficients. More specifically, individual external doses of Tokyo Electric Power Company Holdings employees in difficult-to-return zone were measured broadly over a long period (FY2020 to FY2022). To obtain highly accurate estimates, we used not only ambient dose rates based on airborne radiological monitoring data, but also Integrated dose rate map data that had been statistically corrected to correspond to local ambient dose rate gradients on the ground. As a result, the conversion coefficients based on the ambient dose rate map measured by airborne radiological monitoring were 0.42 for the Evacuation-Order Lifted Zones (ELZs), 0.37 for the Special Zones for Reconstruction and Rehabilitation (SZRRs), and 0.47 for the Difficult-to-Return Zones without a SZRRs (DRZs). On the other hand, the conversion coefficients based on the Integrated dose rate map which is a highly accurate dose rate map based on statistical analysis of various types of monitoring that have been studied in government projects in recent years, were 0.78 for the ELZs, 0.72 for the SZRRs and 0.82 for the DRZs. Using these conversion coefficients, the individual external dose can be estimated from two representative ambient dose rate maps provided by the government. .

Predictive Performance of MRI for Antibiotic Treatment Failure of Pyogenic Vertebral Osteomyelitis: A Validation Study.

INTRODUCTION: Intravenous antibiotics are the primary treatment of choice for pyogenic vertebral osteomyelitis (PVO). Surgical intervention is required when the initial antibiotic treatment fails but is often difficult to perform, especially in older adults with multiple comorbidities, because of the reduced physical activity. The size of the infection signal in the spinal bone on magnetic resonance imaging (MRI) at the time of diagnosis was reported to have a high predictive accuracy for antibiotic treatment failure. However, the sample size was too small for this result to be adopted in clinical practice. Thus, we conducted a validation study of the previous research using a larger sample size. METHODS: We conducted a retrospective review of electronic medical records of patients admitted to the orthopedic department of a university hospital with a diagnosis of PVO between 2006 and 2021, and consecutively included patients without planned PVO surgery on admission and with a sagittal view of T1-weighted spinal MRI at the time of diagnosis. The index test was the percentage involvement of the affected areas in one motion segment on sagittal MRI. We also evaluated other MRI findings, such as bone destruction, segmental instability, epidural abscesses, and multiple sites for their predictive accuracy for antibiotic treatment failure. RESULTS: A total of 82 participants were eligible for the analysis. The presence of ≥90% affected area of one motion segment had a sensitivity of 16.7% and a specificity of 70.3% for future antibiotic treatment failure, resulting in poor predictive performance, with positive (LR+) and negative likelihood ratios of 0.56 and 1.19, respectively. The area under the receiver operating characteristic curve for a 10% increase in the affected area was 0.48. Among the other MRI findings, the presence of bone destruction had a significantly higher predictive accuracy (LR+ 3.11, 95% confidence interval 1.30-7.42). CONCLUSION: An infection signal ≥90% on a T1-weighted MRI of one spinal motion segment did not show sufficient predictive performance for antibiotic treatment failure. Spinal bone destruction had a mild-to-moderate predictive accuracy.

Clinical and neonatal outcomes of individually vitrified human sperm with Cryotop and Cell Sleeper.

Technique for preserving limited number of human spermatozoa is important for successful treatment of patients with azoospermia and cryptozoospermia. This study determined whether the non-biological devices (Cryotop and Cell Sleeper) efficiently vitrify small numbers of human spermatozoa. From December 2011 to December 2018, 10 males with very low sperm numbers managed with a single sperm vitrification method. Post-warmed sperm recovery was similar with both devices. Post-warmed sperm motility and fertilization after intracytoplasmic sperm injection were significantly higher in Cryotop group than in Cell Sleeper group (40.0% vs. 22.0%, P < 0.01 and 50.7% vs. 21.7%, P < 0.01, respectively). The pregnancy rate was 15.4% and 2 healthy babies were born in the Cryotop, while 14.3% and 1 baby in the Cell Sleeper, which did not differ between the groups. Both devices have clinical advantages in terms of easy use and safety, and would be performed more efficiently by using devices with different properties.

Endovascular Treatment of Cerebral Venous Circulation Dysfunction Caused by Hemodialysis Shunt: A Case Report.

Objective: Central venous disease, defined as ≥50% stenosis or obstruction of central veins, is one of many life-threatening complications faced by patients on hemodialysis. It often presents as upper limb edema to the arteriovenous (AV) shunt for hemodialysis, although neurological symptoms are rare. We report a case of central venous disease with neurological symptoms associated with endovascular therapy. Case Presentation: A 79-year-old man presented with status epilepticus. His past medical history included rectal carcinoma when he was 69 years old and indication for hemodialysis when he was 79 years old. However, he had no history of neurological disease or epilepsy. On arrival at our facility, CT perfusion revealed venous circulation dysfunction on the left cerebral hemisphere. DSA demonstrated regurgitation from the AV shunt on left upper limb to the cerebral veins and obstruction of the left subclavian vein. Ligation of the causal AV shunt was deemed difficult due to surrounding edema; therefore, endovascular transarterial coil embolization was performed. After completely occluding the AV shunt, patient's condition improved significantly. The patient was discharged 3 days later without neurologic symptoms, with no recurrence of epilepsy was observed to date. Conclusion: Coil embolization of causal AV shunt significantly improved the neurological symptoms of central venous disease.

Laser-assisted hatching on clinical and neonatal outcomes in patients undergoing single vitrified Blastocyst transfer: A propensity score-matched study.

PURPOSE: This study determined the effect of laser-assisted hatching on the clinical and neonatal outcomes of single vitrified blastocyst transfer. METHODS: From June 2014 to March 2018, 289 matched pairs after propensity score matching were analyzed. During the blastocyst warming procedure, a small section of the zona pellucida area in the empty perivitelline space was sliced off using multiple laser beams. The clinical and neonatal outcomes of the laser-treated group and non-treatment control were analyzed. RESULTS: In the laser-assisted hatching group, significantly higher rates of clinical pregnancy (40.8% vs 29.4%, P < .01) and live delivery (34.3% vs 22.5%, P < .01) were observed compared to the control group. Other variables such as the average gestational weeks, the sex of the baby, birthweight, or congenital malformations were found to have no significant differences in neonatal outcomes. Moreover, all babies were singleton live births. CONCLUSIONS: Single vitrified blastocyst transfer treated with laser-assisted hatching increases the live birth rate and has no adverse effects on neonatal outcomes.

Mechanical Thrombectomy for Acute Ischemic Stroke Caused by Prosthetic Aortic Valve Endocarditis Due to Exophiala dermatitidis Infection: A Case Report.

Prosthetic valve endocarditis (PVE) can cause large cerebral vessel occlusion. Many reports suggested that mechanical thrombectomy (MT) is effective and useful for early diagnosis from the histopathological findings of thrombus. We present the case of a 62-year-old man, with a history of prosthetic aortic valve replacement and pulmonary vein isolation for his atrial fibrillation, who developed a high fever and an acute neurological deficit, with left hemiplegia and speech disorder. He was diagnosed as having an acute right middle cerebral artery embolism and underwent an MT. The embolic source was found to be a PVE vegetation. However, histopathological analysis of the thrombus could not detect the actual diagnosis. Although he was treated for bacterial endocarditis, his blood culture revealed a rare fungal infection with Exophiala dermatitidis not until >3 weeks after admission. Subsequently, a ß-D-glucan assay also indicated elevated levels. Although he underwent an aortic valve replacement on day 36, MRI showed multiple minor embolic strokes till that day. Early diagnosis of fungal endocarditis and detection of the causative pathogen are still challenging, and the disease has a high risk of occurrence of early and repeated embolic stroke. In addition to clinical findings and pathological studies, ß-D-glucan assay might be a good tool for the diagnosis and evaluation of fungal endocarditis.

Effect of equilibration time on clinical and neonatal outcomes in human blastocysts vitrification.

PURPOSE: Prolonged exposure to equilibration solutions may be detrimental to an embryo's developmental potential, whereas a shorter exposure may affect the penetration of cryoprotectants into blastomeres. The purpose of this study was to evaluate the effects of different equilibration times on the clinical and neonatal outcomes of human blastocyst vitrification. METHODS: This is a retrospective study based on data collected between November 2008 and November 2015. A total of 192 blastocysts (80 non-expanded and 112 expanded) obtained from 167 patients were analyzed. The blastocysts were divided into two groups according to their equilibration time: 8-11 minutes or 12-15 minutes. The clinical and neonatal outcomes of warmed blastocysts were evaluated. RESULTS: The survival, implantation, and live birth rates of non-expanded blastocysts were not different between the two groups, but they significantly improved for the expanded blastocysts in the 12-15 minutes group compared to the 8-11 minutes group. The results were similar for the neonatal outcomes after vitrified embryo transfer, when partitioned by equilibration time and blastocyst stage at vitrification. CONCLUSIONS: For the non-expanded blastocysts, a shortened equilibration time (8-11 minutes) is sufficient for effective vitrification.

Evaluation of the effect of piezo-intracytoplasmic sperm injection on the laboratory, clinical, and neonatal outcomes.

PURPOSE: Limited research has been published on the effect of piezo-assisted intracytoplasmic sperm injection (P-ICSI). We evaluated the effect of P-ICSI on the laboratory, clinical, and neonatal outcomes. METHODS: This retrospective study was based on the data collected between April 2011 and October 2016. Total 1348 mature oocytes from 145 patients were analyzed. Laboratory, clinical, and neonatal outcomes of those given conventional intracytoplasmic sperm injection (C-ICSI) and those administered P-ICSI were examined. RESULTS: P-ICSI showed significantly more favorable results, with a survival rate of 97.0% (C-ICSI: 94.1%, P < .010) and a fertilization rate of 83.5% (C-ICSI: 70.6%, P < .001). There were no differences in the blastocyst development rate, implantation rate, miscarriage rate, live birth rate, gestational age, birth weight, proportion of male neonates, cesarean section rate, and congenital abnormalities between the two patient groups. CONCLUSIONS: Our comparison of P-ICSI with C-ICSI showed that P-ICSI significantly improved the survival and fertilization.

[Paroxysmal Atrial Fibrillation after Percutaneous Thrombectomy on Day 5 of Onset of Cerebral Embolism:A Case Report].

INTRODUCTION: We report a case of embolic stroke with an atypical course after endovascular therapy performed during the subacute stage of progressive stroke, where symptom relapse could not be controlled despite medical treatment. CASE PRESENTATION: An 81-year-old woman developed slight weakness in her left leg and was hospitalized three days after the onset of symptoms. On admission, her consciousness was almost clear and she exhibited left hemiparesis. The computed tomography(CT)and magnetic resonance imaging(MRI)revealed a cerebral infarction in the right caudate head and corona radiata, and CT perfusion showed no difference in the cerebral blood flow. However, three-dimensional computed tomography angiography showed right M1 occlusion. Considering the clinical course of the leg weakness without atrial fibrillation, antiplatelet therapy for atherosclerotic cerebral infarction was administered. Five days after the symptom onset, the left hemiparesis deteriorated. CT and diffusion-weighted MRI showed increasing edema associated with the cerebral infarction, and CTP showed decreased cerebral blood flow in the right middle cerebral artery region. Because angiography revealed an obstruction involving a long lesion with loss of contrast, we suspected an embolic stroke. Endovascular surgery was performed successfully using the Penumbra system. Postoperatively, the hemiparesis resolved and the patient was transferred to the rehabilitation hospital. CONCLUSION: In rare cases, patients with an embolic stroke develop gradual progression of symptoms. To differentiate between cardioembolic stroke and atherosclerotic cerebral infarction in such patients, a follow-up examination of the brain blood flow must be performed, especially when there is a change in symptoms. This may provide useful information for intravascular treatment even in the subacute period.

Effect on clinical and neonatal outcomes of blastocelic microsuction prior to vitrification.

PURPOSE: Microsuction (MS) is a technique for mechanically emptying fluid from blastocele using a microneedle. In this study, we evaluated the improvement in clinical and neonatal outcomes of vitrified blastocyst transfer programs when MS of blastocelic fluid was used before vitrification. METHODS: This was a retrospective study based on data collected between March 2014 and August 2016. A total of 317 blastocysts obtained from 211 patients were analyzed. The blastocelic fluid of expanded blastocysts was aspirated completely, and blastocysts were collapsed prior to vitrification. Clinical and neonatal outcomes of warmed blastocysts were compared. RESULTS: The survival rate of the MS blastocyst was significantly higher compared with the nontreatment control (98.7% vs 89.3%, OR: 9.34, 95% CI: 2.35-36.8, P < 0.01). The rates of implantation and live birth were higher in the MS group than in the control group, but the differences were not significant. There were no differences in gestational age, birthweight, proportion of male babies, rates of cesarean section, and congenital abnormalities. CONCLUSION: The MS procedure improved blastocyst survival and had little effect on further embryo development after warming.

Case of atypical femoral fractures that mimicked the typical imaging findings of prostate cancer-induced bone metastasis.

INTRODUCTION: Atypical femoral fractures are atraumatic or minimally traumatic fractures and rare side effects of bone resorption inhibitors. Bone resorption inhibitors are frequently used in the treatment of prostate cancer. CASE PRESENTATION: A 62-year-old man complained of difficulty in walking and left lower limb pain. Androgen deprivation and denosumab therapy for prostate cancer-induced bone metastasis was initiated 27 months ago. Even though the prostate-specific antigen level did not increase, imaging studies indicated the possibility of bone metastasis. The patient underwent bone biopsy; however, no malignancy was detected. Afterward, he had a fall, causing a complete fracture in his left femur. CONCLUSION: Atypical femoral fractures occasionally mimic typical imaging findings and outcomes of bone metastasis. This case is important for recognizing such cases.

[Economic Evaluation of mFOLFOX6-based First-line Regimens for Unresectable Advanced or Recurrent Colorectal Cancer Using Clinical Decision Analysis].

We evaluated four representative chemotherapy regimens for unresectable advanced or recurrent KRAS-wild type colorectal cancer: mFOLFOX6, mFOLFOX6+bevacizumab (Bmab), cetuximab (Cmab), or panitumumab (Pmab). We employed a decision analysis method in combination with clinical and economic evidence. The health outcomes of the regimens were analyzed on the basis of overall and progression-free survival. The data were drawn from the literature on randomized controlled clinical trials of the above-mentioned drugs. The total costs of the regimens were calculated on the basis of direct costs obtained from the medical records of patients diagnosed with unresectable advanced or recurrent colorectal cancer at Yamagata University Hospital and Yamagata Prefecture Central Hospital. Cost effectiveness was analyzed using a Markov chain Monte Carlo (MCMC) method. The study was designed from the viewpoint of public medical care. The MCMC analysis revealed that expected life months and expected cost were 20 months/3,527,119 yen for mFOLFOX6, 27 months/8,270,625 yen for mFOLFOX6+Bmab, 29 months/13,174,6297 yen for mFOLFOX6+Cmab, and 6 months/12,613,445 yen for mFOLFOX6+Pmab. Incremental costs per effectiveness ratios per life month against mFOLFOX6 were 637,592 yen for mFOLFOX6+Bmab, 1,075,162 yen for mFOLFOX6+Cmab, and 587,455 yen for mFOLFOX6+Pmab. Compared to the conventional mFOLFOX6 regimen, molecular-targeted drug regimens provide better health outcomes, but the cost increases accordingly. mFOLFOX 6+Pmab is the most cost-effective regimen among those surveyed in this study.

[Neuro-Endoscopic Surgery for Multi-Lobular Chronic Subdural Hematoma].

BACKGROUND: Chronic subdural hematoma(CSDH)generally occurs in the elderly, and is usually treated by burr-hole craniotomy with closed-system drainage. Treatment of recurrent CSDH is more challenging, especially when the hematoma is multi-lobular. A variety of approaches to the management of multi-lobular CSDH have been described, including evacuation through a wide craniotomy, placement of an Ommaya reservoir, subdural peritoneal shunting, and embolization of the middle meningeal artery. We have previously reported a method of evacuating multi-lobular CSDH through a small craniotomy using a rigid endoscope and aspiration tube. The objective of this study was to compare our operative method with others from the literature. MATERIALS AND METHODS: Between January 2012 and October 2016, eight patients diagnosed with multi-lobular CSDH using computed tomography(CT)imaging underwent endoscopic evacuation. First, we established a 3×3cm craniotomy at a position where a rigid endoscope and aspiration tube would be able to reach as much of the hematoma cavity as possible in the longitudinal plane. Second, after identifying and removing the outer membrane of the CSDH with the scope, we evacuated the hematoma longitudinally, keeping the inner membrane intact. We also applied monopolar diathermy to any obvious bleeding points and the capillary network on the outer membrane of the CSDH, using the aspiration tube. RESULT: The mean duration of surgery was 42 minutes. Follow-up CT scan revealed no recurrence in any of the cases, and neurologic function improved in all patients postoperatively. CONCLUSION: A multi-lobular CSDH can be drained quickly and effectively using a rigid endoscope and aspiration tube through a small craniotomy. In a cohort of eight patients, postoperative neurologic recovery was observed in all cases with no evidence of recurrence. This technique could be used in any facility with ready access to CT imaging and a rigid endoscope.

[Development of a New Neuro-Endoscope Cylinder for Safer Neuro-Endoscopic Surgery].

Objective:Successful endoscopic surgery for intracerebral hemorrhage has previously been hampered by impaired visualization during the operation to remove the clot, leading to a relatively low removal efficiency for hematomas. However, in multiple case series, intracerebral hematomas have been reported to be removed using endoscopic visualization. Although using tubular retractors in cranial surgery is one technique to gain access to deep-seated lesions, it is difficult to confirm the depth of the retractor's sheath in the surgical field using only the outer sheath. We built various-sized cylinders, developed by the Japan Science and Technology Agency's(JST)program for revitalization promotion, with scales that are visible during both endoscopic and radiographic procedures. We report the use of these cylinders in clinical cases. Method and Results:The JST-developed cylinders benefit from new techniques for plating and tantalum film implantation used to form tubes made of fluorinated ethylene propylene. We successfully removed various hematomas using these cylinders, as we were able to clearly visualize the border of the brain parenchyma and the depth of the hematoma using the cylinder. Conclusion:Cylinders with visible scales for both endoscopic and radiographic uses developed by the JST programs may provide greater patient safety during endoscopic surgery. We next plan to improve the hardness, length, and smoothness of the groove on the cylinder.

Successful delivery derived from vitrified-warmed spermatozoa from a patient with nonobstructive azoospermia.

OBJECTIVE: To report the clinical outcomes following intracytoplasmic sperm injection (ICSI) with vitrified sperm from patients with severe male factor infertility. DESIGN: Retrospective case series. SETTING: IVF unit of a medical center. PATIENT(S): Three patients with severe oligozoospermia or nonobstructive azoospermia (NOA). INTERVENTION(S): Cryopreservation of limited numbers of spermatozoa with the use of Cryotop and Cell Sleeper as nonbiologic containers. MAIN OUTCOME MEASURE(S): Four cycles underwent intracytoplasmic sperm injection (ICSI) with vitrified sperm. RESULT(S): A total of 148 spermatozoa in 18 containers (8.2 sperm per container) were vitrified and 36 of them (5 containers) were warmed. Thirty-three sperm (92%) were retrieved successfully and injected individually into 17 mature oocytes. Fertilization was observed in 12 oocytes (71%), and all zygotes (100%) cleaved. A couple with NOA achieved a singleton pregnancy and concluded with full-term delivery of a healthy boy (2,632 g). CONCLUSION(S): A successful delivery was achieved after transfer of a blastocyst derived from vitrified-warmed spermatozoa. A small number of vitrified sperm cells were used for ICSI to fertilize oocytes with predictable timing.

Simple vitrification for small numbers of human spermatozoa.

Conventional freezing procedures and containers are not appropriate for spermatozoa from the testis because of their low number and poor in-situ motility, and various types of container have been utilized to freeze small numbers of spermatozoa. This study tried to develop a vitrification method for small numbers of spermatozoa using the Cell Sleeper, which is a closed type of cell-cryopreservation container. The container with spermatozoa were cooled in liquid nitrogen vapour and then stored in a cryotank. Sperm motility parameters improved significantly (P < 0.05) by vitrification in oil-free droplets rather than in droplets covered with oil. After vitrification of five spermatozoa per container, all spermatozoa were recovered and the viable sperm rate was significantly higher when spermatozoa were vitrified in a 3.5-ll droplet rather than in 0.5 ll (72.0% versus 38.0%; P < 0.01). Recovery, motility and viability rates of vitrified­warmed spermatozoa were similar between the Cell Sleeper and the CryoTop groups. In conclusion, the Cell Sleeper is a highly effective tool for the cryopreservation of small numbers of spermatozoa and limited cells can be vitrified quickly and simply without significant loss.

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.

Separate demonstration of arterial- and venous-phase by 3D-CT angiography for brain tumors using 64-multidetector row CT: 3D-CT arteriography and 3D-CT venography.

We assessed the usefulness of the separate demonstration of the arterial- and venous phase on 3D-CT angiography (3D-CTA) using a 64-multidetector row CT (MDCT) scanner for the surgery of brain tumors. Nineteen patients with meningiomas (n=11), schwannomas, metastatic brain tumors (n=2 each), glioblastoma multiforme, malignant lymphoma, craniopharyngioma, and embryonal carcinoma (n=1 each) underwent scanning on a 64-MDCT scanner. After dynamic CT scanning to determine the scan timing for the arterial- and venous-phase, we individually scanned the arterial- and venous phase for 4 sec after injecting a nonionic contrast medium. Using the CT threshold setting and subtraction and cutting techniques, we produced individual 3D-CT images of the arteries, veins, tumors, and bones. The operators subjectively assessed the usefulness of these images in comparison with 3D-CTA. We separately demonstrated the arterial- and venous phase on 3D-CTA covering the entire head in all 19 cases. The 3D-CT arteriographs, 3D-CT venographs, and the fused 3D-CT images facilitated our understanding of the 3D anatomic relationship among the tumor, arteries, veins, and bony structures. In 14 of 19 cases our method provided the surgically valuable findings; the information on the anatomical relation between tumor and the surrounding arteries and veins (in 13 cases) the identification of anatomical course of the encased vessels (in one), and feeding arteries and draining veins (in one), and discrimination between the venous sinus and tumor (in one). The anatomical information yielded by our technique makes safer surgery possible. If more detailed information which 3D-CTA cannot provide is required, our method should be performed.

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.