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Megumi Takahashi,1 Hiroshi Okudera,2 Masahiro Wakasugi,2 Mie Sakamoto,2 Hiromi Shimizu,3 Tokie Wakabayashi,3 Tsuneaki Yamanouchi,3 Hisashi Nagashima2 1Department of Quality and Patient Safety, Tokyo Medical University, Tokyo, Japan; 2Department of Crisis Medicine and Clinical Safety, University of Toyama, Toyama, Japan; 3Department of Medical Management Office, Toyama University Hospital, Toyama, JapanCorrespondence: Megumi Takahashi, Department of Quality and Patient Safety, Tokyo Medical University, 6-7-1, Nishishinjuku, Shinjuku, Tokyo, Japan, Tel +81 3 3342 6111 Ext 3939, Fax +81 3 5339 3791, Email megu3@tokyo-med.ac.jpPurpose: Our aim was to inform a new definition of wrong-patient errors, obtained through an analysis of incident reports related to medication errors.Methods: We investigated wrong-patient medication errors in incident reports voluntarily reported by medical staff using a web-based incident reporting system from 2015 to 2016 at a university hospital in Japan. Incident report content was separately evaluated by four evaluators using investigational methods for clinical incidents from the Clinical Risk Unit and the Association of Litigation and Risk Management. They investigated whether it was the patient or drug that was incorrectly chosen during wrong-patient errors in drug administration in incident reports and assessed contributory factors which affected the error occurrence. The evaluators integrated the results and interpreted them together.Results: Out of a total 4337 IRs, only 30 cases (2%) contained wrong-patient errors in medication administration. The cases where the intended drugs were administered to incorrect patients occurred less frequently than cases where the wrong drugs were administered to the intended patients through the investigation of wrong targets. After a discussion, the evaluators concluded that the patient - drug/CPOE screen mismatch, caused by choosing the wrong patient, drug, or CPOE screen (mix-ups), occurred in the wrong-patient medication errors. These errors were caused by three conditions: (1) where two patients/drugs were listed next to one another, (2) where two patients’ last names/drugs’ names were the same, and (3) where the patient/drug/CPOE screen in front of the staff involved was believed to be the correct one. Additionally, these errors also involved insufficient confirmation, which led to failure to detect and correct the mismatch occurrences.Conclusion: Based on our study, we propose a new definition of wrong-patient medication errors: they consisted of choosing a wrong target and insufficient confirmation. We will investigate other types of wrong-patient errors to apply this definition.Keywords: wrong-patient error, medication error, web-based incident reporting system, computerized physician order entry, human error

Amnion membrane studies related to miscarriage have been conducted in the field of obstetrics and gynecology. However, the distribution of stem cells within the amnion and the differences in the properties of each type of stem cells are still not well understood. We address this gap in knowledge in the present study where we morphologically classified the amnion membrane, and we clarified the distribution of stem cells here to identify functionally different amniotic membrane–derived stem cells. The amnion can be divided into a site that is continuous with the umbilical cord (region A), a site that adheres to the placenta (region B), and a site that is located opposite the placenta (region C). We found that human amnion epithelial stem cells (HAECs) that strongly express stem cell markers were abundant in area A. HAEC not only expressesed stem cell-specific surface markers TRA-1-60, Tra-1-81, SSEA4, SSEA3, but was also OCT-3/4 positive and had alkaline phosphatase activity. Human amniotic mesenchymal stem cells expressed KLF-A, OCTA, Oct3/4, c-MYC and Sox2 which is transcription factor. Especially, in regions A and B they have expressed CD73, and the higher expression of BCRP which is drug excretion transporter protein than the other parts. These data suggest that different types of stem cells may have existed in different area. The understanding the relation with characteristics of the stem cells in each area and function would allow for the efficient harvest of suitable HAE and HAM stem cells as using tool for regenerative medicine.

Koji Shimizu, Masahiro Wakasugi, Toshiomi Kawagishi, Tomoya Hatano, Takamasa Fuchigami, Hiroshi Okudera Emergency and Disaster Medicine, University of Toyama, Toyama, JapanCorrespondence: Masahiro WakasugiEmergency and Disaster Medicine, University of Toyama, 930-0194 Sugitani, Toyama, JapanTel +81 76-434-7786Fax +81 76-434-5110Email mwaka@med.u-toyama.ac.jpPurpose: To obtain effective systemic blood flow and coronary perfusion by chest compressions during cardiopulmonary resuscitation, it is recommended that the interruption time of chest compressions be kept to a minimum, and that the chest compression fraction (CCF) should be kept high. In this study, we examined the effects of advanced airway management by paramedics in out-of-hospital cardiac arrest (OHCA) cases on CCF and on return of spontaneous circulation (ROSC) before arrival at the hospital.Participants and Methods: A total of 283 adult, non-traumatic OHCA cases who were in cardiopulmonary arrest at the time of EMS contact between April 2015 and March 2017 were registered for this study. We retrospectively investigated the presence or absence of advanced airway clearance, CCF and ROSC during CPR. CCF was calculated by measuring the chest compression interruption time from the ECG waveform recorded on a semiautomatic defibrillator (Philips HeartStart MRX). The data obtained were recorded on a computer, and comparisons between groups were examined using an untested t-test and χ2- test.Results: Of the 283 patients with OHCA, 159 were included in the analysis. The CCF of the AAM group was 89.4%, which was significantly higher than that in the BMV group (84.3%) (P< 0.01). Forty-one patients had ROSC at the time of arrival at the hospital, and the CCF of ROSC patients was 89.7%, which was significantly higher than that of non-ROSC patients (87.2%) (P< 0.01). ROSC was also obtained in 31.8% of the patients in the AAM group, which was significantly higher than that in the BMV group (12.2%).Conclusion: In this study, we found that advanced airway management during prehospital emergency transport by paramedics showed high CCF and ROSC rates and contributed to improving the prognosis of OHCA patients through high-quality resuscitation.Keywords: cardio pulmonary resuscitation, endotracheal intubation, supraglottic airways devices, outcome

Mass gatherings are events characterized by “the concentration of people at a specific location for a specific purpose over a set period of time that have the potential to strain the planning and response resources of the host country or community.” Previous reports showed that, as a result of the concentration of people in the limited area, injury and illness occurred due to several factors. The response plan should aim to provide timely medical care to the patients and to reduce the burden on emergency hospitals, and to maintain a daily emergency medical services system for residents of the local area. Although a mass gathering event will place a significant burden on the local health‐care system, it can provide the opportunity for long‐term benefits of public health‐care and improvement of daily medical service systems after the end of the event. The next Olympic and Paralympic Games will be held in Tokyo, during which mass gatherings will occur on a daily basis in the context of the coronavirus disease (COVID‐19) epidemic. The Academic Consortium on Emergency Medical Services and Disaster Medical Response Plan during the Tokyo Olympic and Paralympic Games in 2020 (AC2020) was launched 2016, consisting of 28 academic societies in Japan, it has released statements based on assessments of medical risk and publishing guidelines and manuals on its website. This paper outlines the issues and countermeasures for emergency and disaster medical care related to the holding of this big event, focusing on the activities of the academic consortium., This article describes medical problems, tasks, and topics at mass gathering events. It also introduces the current activities of the Academic Consortium on Emergency Medical Services and Disaster Medical Response Plan during the 2020 Tokyo Olympics (AC2020), consisting of 28 medical societies in Japan.

Most patients with coronavirus disease 2019 (COVID-19) have just only mild symptoms, but about 5% are very severe. Although extracorporeal membranous oxygenation (ECMO) is sometimes used in critically patients with COVID-19, ECMO is only an adjunct, not the main treatment. If the patient's condition deteriorates and it is determined to be irreversible, it is necessary to decide to stop ECMO. A 54-year-old man was admitted on day 6 of onset with a chief complaint of high fever and cough. Computed tomography (CT) showed a ground glass opacity in both lungs, and reverse transcription-polymerase chain reaction (RT-PCR) diagnosed COVID-19. He was admitted to the hospital and started to receive oxygen and favipiravir. After that, his respiratory condition deteriorated, and he was intubated and ventilated on day 9 of onset, and ECMO was introduced on day 12. Two days after the introduction of ECMO, C-reactive protein (CRP) increased, chest X-p showed no improvement in pneumonia, and PaO2/FiO2 decreased again. As D-dimer rose and found a blood clot in the ECMO circuit, we had to decide whether to replace the circuit and continue with ECMO or stop ECMO. At this time, the viral load by RT-PCR was drastically reduced to about 1/1750. We decided to continue ECMO therapy and replaced the circuit. The patient's respiratory status subsequently improved and ECMO was stopped on day 21 of onset. In conclusion, viral load measurement by RT-PCR may be one of the indicators for promoting the treatment of severe COVID-19 patients.

OBJECTIVES To analyze incidents related to Foley catheter insertion and maintenance, and to compare the rate of incidents before and after a medical staff education program. METHODS Data regarding Foley catheter insertion incidents and maintenance were collected at Toyama University Hospital, Toyama, Japan. The degree of harm for each incident was assessed. In the middle of the study period, a medical staff education program by urologists was implemented to help understand basic urological anatomy, urethral catheter insertion techniques and catheter safety. The incidents before and after the intervention were then compared. RESULTS During the study period, Foley catheter insertion was carried out in 12 476 patients. Related incidents were reported in 66 (0.53%), including 22 (0.18%) occurring during catheter insertion and 44 (0.35%) occurring during catheter maintenance. A total of 13 (0.10%) cases of urethral injury were reported. The degree of harm associated with catheter insertion incidents was moderate in 13. Nine of these incidents occurred before the education program (9/6799, 0.13%), and four were reported after the end of the program (4/5677, 0.07%, P = 0.4303). Transient suprapubic cystostomy was required in two due to urethral injury reported before the program. Among 44 incidents occurring during catheter maintenance, 37 catheters were removed or cut by the patient. Such incidents occurred regardless of the education program. CONCLUSIONS The rate of incidents related to Foley catheter use at our institution is low. A specific medical staff education program might prevent iatrogenic catheter-related urethral injury requiring cystostomy.

BackgroundSevere burn injuries create large skin defects that render the host susceptible to bacterial infections. Burn wound infection often causes systemic sepsis and severe septicemia, resulting in an increase in the mortality of patients with severe burn injuries. Therefore, appropriate wound care is important to prevent infection and improve patient outcomes. However, it is difficult to heal a third-degree burn injury. The aim of this study was to investigate whether hyperdry human amniotic membrane (HD-AM) could promote early granulation tissue formation after full-thickness skin excision in third-degree burn injury sites in mice.MethodsAfter the development of HD-AM and creation of a third-degree burn injury model, the HD-AM was either placed or not placed on the wound area in the HD-AM group or HD-AM group, respectively. The groups were prepared for evaluation on postoperative days 1, 4 and 7. Azan staining was used for granulation tissue evaluation, and estimation of CD163, transforming growth factor beta-1 (TGF-β1), vascular endothelial growth factor (VEGF), CD31, alpha-smooth muscle actin (α-SMA) and Iba1 expression was performed by immunohistochemical staining. Quantitative reverse-transcription polymerase chain reaction (PCR) was used to investigate gene expression of growth factors, cell migration chemokines and angiogenic and inflammatory markers.ResultsThe HD-AM group showed significant early and qualitatively good growth of granulation tissue on the full-thickness skin excision site. HD-AM promoted early-phase inflammatory cell infiltration, fibroblast migration and angiogenesis in the granulation tissue. Additionally, the early infiltration of cells of the immune system was observed.ConclusionsHD-AM may be useful as a new wound dressing material for full-thickness skin excision sites after third-degree burn injuries, and may be a new therapeutic technique for improving the survival rate of patients with severe burn injuries.

Objectives: Medical oncologists and pharmacists at our institution established an integrated support program aimed at preventing unnecessary treatment interruption or dose reduction during oral targeted therapy with lenvatinib. Here, we evaluated the benefits of this program in managing patients with thyroid cancer receiving lenvatinib. Methods: We retrospectively evaluated thyroid cancer patients who received lenvatinib between May 2015 and March 2017. This descriptive study collected records in which pharmacists contributed to changing doctors’ prescriptions and categorized the interventions. Results: During the study period, 24 thyroid cancer patients were treated with lenvatinib. Among patients, the incidence of temporary interruption and dose reduction of lenvatinib due to adverse drug reactions was 100% (n = 24) and 83.3% (n = 20), respectively. There were 193 temporary interruptions of lenvatinib due to adverse drug reactions. A total of 501 outpatient pharmacy services were conducted by pharmacists in collaboration with oncologists, of which 125 were interventions (24.9%). In addition, pharmacists conducted 156 telephone follow-up services; 18 (11.5%) of these were to consult an oncologist about a patient’s confirmed problems and resulted in the decision to continue observation with no medical intervention while 41 (26.2%) resulted in the oncologist deciding to temporarily interrupt lenvatinib treatment after the report of an adverse drug reaction from the pharmacist. Conclusion: Pharmacist interventions in collaboration with medical oncologists improved lenvatinib therapy. Interventions for outpatients were conducted not only in outpatient clinics but also by telephone follow-up, clarifying the importance of continuous management for patients at risk of adverse reactions and misuse of oral medicine.

Background Among Organisation for Economic Co-operation and Development countries, the number of cadaveric donors per population is the lowest in Japan. The present study investigated whether a continuing educational intervention for medical staff, such as Donor Action Program (DAP) that is aimed at increasing the number of cadaveric donors, improved the confirmation rate of organ donation in potential donors. Material and Methods We studied 2 hospitals with emergency centers in Toyama, Japan. DAP was conducted 2 to 3 times each year. We extracted mortality cases recorded in the emergency care departments of each hospital for over 10 years between 2007, prior to DAP’s implementation, and 2017 to examine the confirmation rate of the intent of the families of potential donors for organ donation and the timing and methods for confirming intent to donate in cases that resulted in organ donation. Results The confirmation rate increased after the introduction of DAP and remained high (over 80%) in both hospitals after 2012. Regarding actual organ donation, some patients were asked by staff about their intent when they became potential donors in addition to the hospitalization intake form; it was offered by family members of some of the patients. Conclusion Regular educational training on organ donation improved the confirmation rate of potential organ donors’ donation intention. For organ donation, medical practitioners must take the appropriate steps to confirm the patient’s intent to donate when he/she is determined as a potential donor.

Background Disseminated intravascular coagulation (DIC) associated with multiple organ dysfunction syndrome (MODS) plays pivotal roles in severe sepsis. Objectives We performed a multicenter, prospective data collection study and retrospectively analyzed the data to confirm the role of DIC in severe sepsis. Methods Eligible patients were ICU patients who met the definitions of severe sepsis, and 1013 patients were included. DIC scores as well as disease severity and the development of MODS on the day of the diagnosis of severe sepsis (day 0) and at day 3 were evaluated. The primary outcome was hospital mortality, and MODS on days 0 and 3 was the secondary outcomes. Results The overall mortality rate of severe sepsis was 21.5%, and the prevalence of DIC was 50.9% (516/1013). DIC patients were more seriously ill and exhibited a higher prevalence of MODS (32.0% vs. 13.1%) on day 0 and worse mortality rate (24,8% vs. 17.5%) than non-DIC patients. DIC patients also showed a lower survival probability than non-DIC patients (Log rank p = 0.028). Logistic regression analyses after propensity score adjustment for potential confounders confirmed a significant association between DIC and MODS and hospital death in the patients with severe sepsis. The new development of DIC and persistent DIC from days 0 to 3 were associated with a high incidence of MODS and low survival probability. Conclusions The mortality rate of severe sepsis has been improved; however, DIC is still associated with the poor prognosis of these patients. Evaluating the dynamic changes in the DIC status may improve the prediction capability.

Objective In Japan, stroke care is provided through medical cooperation and standardized treatment. However, various factors affect mortality in the hyperacute phase. The present study investigated factors associated with death within 24 h after admission for acute stroke. Methods Among 2335 patients admitted within 24 h after stroke onset from 1 January 2007 to 31 December 2012, a total of 139 deaths occurred. Forty-eight deaths occurred within 24 h after admission. We retrospectively examined the clinical features of these 48 patients. Results The overall mortality rate was 6.0%. When the initial 72-h period was divided into ≤24 h (Period I), >24 to 48 h (Period II), and >48 to 72 h (Period III), deaths were significantly more frequent in Period I than in the other two periods. The frequency of intracerebral haemorrhage (ICH) was also significantly higher in Period I than in the other two periods. Factors significantly associated with death from ICH were systolic blood pressure, hematoma volume, and surgery. Conclusion The mortality rate was low among patients with stroke transported to the authors’ medical center within 24 h of onset. Blood pressure management and the timing of determining indications for surgery are important factors in acute haemorrhagic stroke care.

On November 22, 2010, a simulation-based hands-on education course for medical staff in the neurosurgical fields was held in 8 th Asian Congress of Neurological Surgeons (ACNS) in Kuala Lumpur, Malaysia. The present education course called Primary Neurosurgical Life Support (PNLS) course had been started by the Japan Society of Neurosurgical Emergency since 2008. This report summarizes the international version of PNLS course in 8 th ACNS.

Valacyclovir (VACV) is used increasingly to treat herpes zoster, although neuropsychiatric symptoms [VACV neurotoxicity (VAN) or acyclovir neurotoxicity], may accompany use of this drug. To promote awareness of this rare condition, we describe here two clinical cases of VAN we previously reported and review 20 cases from the literature. In all cases, chronic or acute renal failure preceded VAN. The symptoms of VAN varied, but disturbances of consciousness and hallucination occurred most commonly. When acute renal failure was due to the drug, recovery from both the disturbance of consciousness and renal failure followed within several days after discontinuation of VACV. Early recognition and diagnosis will ensure effective treatment of VAN.

症例1 : 63歳, 男性. 右完全片麻痺, 全失語にて発症. CTにて明らかな異常を認めず, 脳血管撮影にて巨大塞栓子による左頚部内頚動脈閉塞を認めた. 血栓の脇にカテーテルを進め末梢側で造影したところ, 内頚動脈分岐部で閉塞を認めた. 末梢部の血栓溶解を施行し側副血行路を開通させ, 症状の回復が見られたが, 2日後に頚部血栓が末梢へ移動し, 高度の後遺症が残存した. 症例2 : 79歳, 男性. 右不全片麻痺, 失語にて発症. 脳血管撮影では, 巨大塞栓子による左頚部内頚動脈閉塞を認め, 側副血行により左中大脳動脈が描出された. 左内頚動脈が逆行性に錐体部まで描出されていたため, 緊急で頚動脈血栓摘出術を施行し, 術後, 症状の改善が見られた. 巨大塞栓子による急性期頚部内頚動脈閉塞症は稀な疾患であり, 血栓溶解療法による再開通が困難で, 開通した場合でも末梢塞栓を起こしやすい. われわれが経験した2症例を踏まえ, 治療フローチャートを提唱する.

According to the 2010 neuroresuscitation guideline, status epilepticus (SE) is a critical condition that causes respiratory and circulation dysfunction, including "acute consciousness disturbance" and "elevated intracranial pressure." There are two types of SE: general convulsive SE (GCSE) and nonconvulsive SE (NCSE). GCSE is easily diagnosed because the patients show continuous convulsions. In contrast, NCSE can only be diagnosed by electroencephalography (EEG), which can delay diagnosis. Moreover, GCSE and NCSE occasionally manifest in the same patient and alternate. Here, we describe the case of a 64-year-old male patient who experienced losses of consciousness mimicking stroke. We could not diagnose these episodes as NCSE until the patient had a general continuous convulsion. In this case, the delayed diagnosis of NCSE resulted in uncontrollable GCSE that required intensive management, including mechanical ventilation under sedation. It is important to recognize that NCSE can cause consciousness disturbance and to initiate treatment as soon as possible to improve patient prognosis. This could be achieved by performing an EEG earlier, such as at the scene of emergencies.

Immediate Stroke Life Support (ISLS) is a curriculum for evaluation and management of acute stroke syndromes. ISLS was developed by Japan ISLS task force consisting of Japanese Association of Acute Medicine (JAAM) and Japanese Congress on Neurological Emergencies (JCNE). The course incorporates role play, mannequin simulation modalities, and clinical maps. ISLS has undergone a collaborative iterative process from Japanese to enable English language / North American student participation. ISLS complements the neurological skills and knowledge which are essential to cerebral resuscitation. This program will introduce teachers to the techniques used in this course, through sequential train-the-trainer exercises in each of the integrated simulation techniques.

Treatment options for cerebral arteriovenous malformation (AVM) are still controversial due to the recent result of stereotactic radiosurgery and the improved result of microsurgical resection. We investigated previously treated AVM cases and discussed the efficacy and safety of preoperative embolization especially for microsurgical resection of high-grade AVM in the Spetzler-Martin grading. Efficacy of preoperative embolization was evaluated based on 126 previously treated AVM cases at Shinshu University Hospital during the last 25 years. The safety of embolization was evaluated based on our previously-embolized 58 AVM cases (91 procedures) in the last 11 years after introduction of preoperative embolization for AVM. In all 126 cases, 82 were treated before introduction of embolization and 44 were treated after introduction of embolization. In 82 cases of the pre-embolization era, 63 lesions were removed totally in 63 AVMs (77%), partially resected in 11 (13%) and untreated in eight (10%). In 74 surgically removed cases, 11 (15%) cases showed severe intra/postoperative bleeding. In 44 cases of the embolization era, lesions were removed totally in 29 AVMs (66%), disappeared only with embolization in one (2%), disappeared with radiosurgery in seven (16%) and were untreated in five (11%). In 32 surgically removed cases, only one (2%) case showed severe intra/postoperative bleeding. In all 58 embolized cases, 44 were surgically removed, six were treated with radiosurgery, one was eliminated with embolization alone and six were partially obliterated and followed up for their location. In 91 procedures for 58 cases, two haemorrhagic and three ischemic complications occurred, three were transient and two remained having neurological deficits. The introduction of preoperative embolization improved the total removal rate and reduced the intra/postoperative bleeding rate in surgical removal of AVM. The total risk of embolization is low and well-designed preoperative embolization makes surgical resection safer even in high-grade AVM in the Spetzler-Martin grading.

Objective Microneurosurgery can be performed less invasively with the recent advances in neuronavigation and neuroendoscopy. For even less invasive microneurosurgery, we have developed a telecontrolled micromanipulator system. Methods The NeuRobot telecontrolled micromanipulator system was developed. With the use of this system, surgical simulations were performed with a human cadaveric head. Results The system consists of four main parts, i.e., a micromanipulator (slave manipulator), a manipulator-supporting device, an operation-input device (master manipulator), and a three-dimensional display monitor. Three 1-mm forceps and a three-dimensional endoscope, which could be remotely controlled with three degrees of freedom (rotation, neck swinging, and forward/backward motion), were installed in the slave manipulator. All surgical procedures were accurately performed with this system. Conclusion The use of telecontrolled manipulator systems in neurosurgery is very promising, and we are convinced that this system will facilitate more accurate, less invasive microneurosurgery. The details of the NeuRobot system and preliminary results are presented.

Clinical features on the first unexpected nerve gas terrorism using sarin (isopropyl methylphosphonofluoridate) on citizens in the city of Matsumoto is described. The nerve gas terrorism occurred at midnight on 27 June, 1994. About 600 people including residents and rescue staff were exposed to sarin gas. Fifty-eight victims were admitted to hospitals and seven died. Theoretically, sarin inhibits systemic acetylcholinesterase and damages all the autonomic transmission at the muscarinic and nicotinic acetylcholine receptor. Miosis was the most common finding in the affected people. In cases with severe poisoning, organophosphate may affect the central nervous system and cause cardiomyopathy. A few of the victims complained of arrhythmia and showed a decreased cardiac contraction. Abnormal electroencephalograms were recorded in two patients. The clinical features and follow-up studies are discussed with reference to the Tokyo subway terrorism and related articles.

Cavernous angioma of the pineal region is rare, as is brain tumour coincident with Parkinsonism. The authors describe the case of a 55 year old woman with a pineal region cavernous angioma, who subsequently developed Parkinsonism after her increased intracranial pressure was relieved. The cause of Parkinsonian syndrome is unclear, but compression of the posterior thalamus and upper mid-brain with congestion of the deep venous system may have caused vascular disturbance of the nigro-striate-pallidal system. Her symptoms gradually improved after total excision of the lesion.

Owing to the deep location of the posterior cerebral artery (PCA) and its close relationship with the brainstem and surrounding vital structures, surgical treatment of aneurysms in this region is complex. This study was undertaken in an attempt to better delineate the surgical risks of PCA aneurysms. A retrospective analysis was undertaken in 11 patients with PCA aneurysm surgically treated between 1988 and 1996 at Shinshu University and its affiliated hospitals. Data regarding surgical strategy, surgical complications and outcomes were analysed. Seven aneurysms were saccular (including one mycotic) and the other four were fusiform, dissecting, thrombosed and an infundibular dilatation. The locations of the aneurysms were at the P1 segment in two patients, P1-P2 junction in two, P2 segment in six and P3 segment in one. Six saccular non-mycotic aneurysms were treated with neck clipping and the other five aneurysms were treated each with proximal occlusion of the parent artery, excision of the aneurysm or wrapping. All aneurysms were satisfactorily exposed except one large saccular aneurysm. Surgical outcomes were either good recovery or moderate disability in 10 patients, and severe disability in one patient with a large aneurysm due to temporal lobe contusion. In conclusion it is the responsibility of the surgeon dealing with rare PCA aneurysms to be aware of these specific characteristics and to appreciate which surgical technique is appropriate for each patient.

In this article we demonstrate a computer graphics model to represent the microsurgical anatomy of the supraclinoid portion of the internal carotid artery (ICA). The source of the input data is a variety of publications showing the detailed anatomy of the area. A computer graphics model of the supraclinoid portion of the ICA and relevant structures including perforators and cranial nerves was made under full colour shading using a Z-buffer algorithm. Complicated microstructures including perforators or cranial nerves are depicted in detail, and can be rotated and viewed from any direction, and thus allows understanding of the three-dimensional relations of the area. Using our method, it may be possible to represent more complicated models of various anatomies, and this methodological tool would be useful for teaching surgical microanatomy and pathology and in pre-surgical operative planning and preparation of the surgeon, introducing a new style navigational system for open microneurosurgery.

Two cases of overlooked, traumatic unilateral occlusion of the carotid artery are reported. Postmortem revealed occlusion of the internal carotid artery in one case and that of the common carotid artery in another. The progression of the morbid state, along with the management with emphasis on the significance of the carotid angiogram and follow-up repeated computed tomography are mentioned. Although traumatic occlusion of the common carotid artery is not as common as that of the internal carotid artery, both entities are well known to produce morbidity and mortality.

✓ The authors' goal was to develop a computer graphics model to simulate the displacement and morphological changes that are caused by the retraction of fine intracranial structures.The authors developed an application program to interpolate the contour of models of an artery and a retractor. The center of the displacement was determined by spatial coordinates, and the shape of the displacement of the arterial model was calculated using a cosine-based formula with representation of a brain retractor. This computer graphics model was applied to the simulation of the displacement and morphological changes that occur when retraction is performed in the optic nerve. An illustrative case is presented, in which the optic nerve was displaced by a retractor to simulate the surgery performed in a carotid cave aneurysm of the internal carotid artery.The authors have named this methodological tool a “virtual retractor.” This new navigational system for open microneurosurgery would be useful in teaching surgical microanatomy and in presurgical operative planning.

To represent multiple microstructures, including perforators, dura, and cranial nerves, and to allow understanding of the three-dimensional relations of the paraclinoid area, we made a computer graphics model. The source of the input data is a variety of publications showing the detailed anatomy of the paraclinoid area. To produce the model, we traced such data, input selected points for each structure, smoothed the lines with a spline program, and added depth using wire-framing and color alterations. The computer graphic model of the paraclinoid area showing perforators, dural ring, optic nerve, and so forth, was made using a paint method for hidden line removal. It can be rotated and viewed from any direction and thus allows understanding of the relations of the area. Using our method, it may be possible to obtain a more detailed model of various anatomies including the skull base, and such data would be useful for preoperative simulation to understand relative regional relations for a specific case and as a new navigational system for open microneurosurgery. Concepts and technical details of the method are described.