川平 洋

Surgeons have increased physical stress during laparoscopic surgery due to operative site constraints. We developed a wearable device to reduce the physical stress on surgeons' lower extremities. The device mechanically facilitates maintaining a near-upright posture. The surgeon's knees are gently bent by a knee-joint locking mechanism, and fixing and releasing are performed independently on each side. The subjects were one female and two male surgeons, who wore the device during laparoscopic inguinal hernia repair or high anterior resection. Surface electromyogram (EMG) was conducted for both iliopsoas muscles. Control values were determined with the subject not wearing the device. Participants completed a post-procedure questionnaire. With the device, EMG activity had a tendency to decrease in the left iliopsoas muscle (P = .055), but it changed little on the right (P = .406). The post-procedure questionnaire showed an overall positive impression, although subjects reported some difficulty walking. This device decreases EMG activity and may improve a surgeon's work environment.

背景:近年、国内外において、脱出ゲーム(ER)を用いた教育実践が増加している。方法:医学部1年生に対し、既存知識の確認とチームでの協力性を学習させる目的でERを用いた授業を行った。70分の授業時間のうち45分をERに用いた。パズル的な謎に加え、BLSなどのタスクも含めた運用を行った。また、最終的な回答を複数用意した分岐の導入など、学生の意欲を高めるための方策を取り入れた。結果:授業の運営を通じて、謎やストーリーの作成にかかる負荷、当日の人員確保などの課題が明らかになった。考察:ERを用いた教育実践に関しては包括的な調査が少ない。事例の整理を通じ、効果的な実践方法の検討を重ねる必要がある。(著者抄録)

BACKGROUND: Helicobacter pylori (H. pylori) eradication is required to reduce incidence related to gastric cancer. Recently, it was found that even after the successful eradication of H. pylori, an increased, i.e., moderate, risk of gastric cancer persists in patients with advanced mucosal atrophy and/or intestinal metaplasia. This study aimed to develop a computer-aided diagnosis (CAD) system to classify the status of H. pylori infection of patients into three categories: uninfected (with no history of H. pylori infection), currently infected, and post-eradication. METHODS: The CAD system was based on linked color imaging (LCI) combined with deep learning (DL). First, a validation dataset was formed for the CAD systems by recording endoscopic movies of 120 subjects. Next, a training dataset of 395 subjects was prepared to enable DL. All endoscopic examinations were recorded using both LCI and white-light imaging (WLI). These endoscopic data were used to develop two different CAD systems, one for LCI (LCI-CAD) and one for WLI (WLI-CAD) images. RESULTS: The diagnostic accuracy of the LCI-CAD system was 84.2% for uninfected, 82.5% for currently infected, and 79.2% for post-eradication status. Comparisons revealed superior accuracy of diagnoses based on LCI-CAD data relative based on WLI-CAD for uninfected, currently infected, and post-eradication cases. Furthermore, the LCI-CAD system demonstrated comparable diagnostic accuracy to that of experienced endoscopists with the validation data set of LCI. CONCLUSIONS: The results of this study suggest the feasibility of an innovative gastric cancer screening program to determine cancer risk in individual subjects based on LCI-CAD.

Accumulating evidence suggests that metformin reduces the incidence and mortality of colorectal cancer (CRC). However, underlying mechanisms have not been fully clarified. The aim of this study was to examine the pathological characteristics of resected CRC from patients treated with metformin for type 2 diabetes mellitus (DM). In total, 267 patients with DM underwent curative colectomy for Stage I-III CRC and 53 (19.9%) patients had been treated medically including metformin. Pathological N-stage was significantly lower in metformin-treated patients (P < .05) with prolonged disease-free survival (DFS) (P < .05). Immunohistochemistry showed that the densities of CD3(+) and CD8(+) tumor-infiltrating lymphocytes (TILs) in the invasive front area were significantly higher in 40 patients treated with metformin compared with propensity score matched cases without metformin (P < .05). The density of tertiary lymphoid structures (TLS) in tumor stroma was markedly increased in metformin-treated patients (P < .001). In those tumors, there were more CD68(+) tumor-associated macrophages (TAM) infiltrated (P < .05), while the ratio of CD163(+) M2-phenotype was markedly reduced (P < .001). Stromal fibrosis tended to be suppressed by metformin intake (P = .051). These findings suggested that metformin drastically changes the characteristics of infiltrating immune cells in CRC and reprograms the tumor microenvironment from immunosuppressive to immunocompetent status, which may lead to suppression of microscopic tumor spread and improve the outcomes of patients with CRC and type 2 DM.

Objectives: To evaluate the effect of simulator fidelity on procedure skill training through a review of existing studies. Methods: MEDLINE, OVID and EMBASE databases were searched between January 1990 and January 2019. Search terms included "simulator fidelity and comparison" and "low fidelity" and "high fidelity" and "comparison" and "simulator". Author classification of low- and high-fidelity was used for non-laparoscopic procedures. Laparoscopic simulators are classified using a proposed schema. All included studies used a randomized methodology with two or more groups and were written in English. Data was abstracted to a standard data sheet and critically appraised from 17 eligible full papers. Results: Of 17 studies, eight were for laparoscopic and nine for other skill training. Studies employed evaluation methodologies, including subjective and objective measures. The evaluation was conducted once in 13/17 studies and before-after in 4/17. Didactic training only or control groups were used in 5/17 studies, while 10/17 studies included two groups only. Skill acquisition and simulator fidelity were different for the level of training in 1/17 studies. Simulation training was followed by clinical evaluation or a live animal evaluation in 3/17 studies. Low-fidelity training was not inferior to training with a high-fidelity simulator in 15/17 studies. Conclusions: Procedure skill after training with low fidelity simulators was not inferior to skill after training with high fidelity simulators in 15/17 studies. Some data suggest that the effectiveness of different fidelity simulators depends on the level of training of participants and requires further study.

自治医科大学メディカルシミュレーションセンター(以下、当SC)は年1万人以上が利用しており、予約管理を効果的・効率的に行えていないことが課題であった。また、利用者が手軽に予約できる仕組みを構築することも求められていた。そこで、当SCではオンライン予約管理システムを開発し、2018年4月より導入した。本邦の多くのシミュレーションセンター(以下、SC)においても、利用者数増加に伴い同様の課題を抱える傾向にあるが、システムの効果に言及した報告は少なく、多くのSCにとって導入のための効果判断の情報が少ない。そこで本稿では予約管理システムの導入から半年間の当SC利用者の利用形態を分析し、その短期的影響について報告する。(著者抄録)

従来、シミュレーションセンターにおける予約管理システムは管理者や教育者の支援としての位置づけが強く、(1)実施日時(2)学習者(3)教育者(4)利用シミュレータ(5)実施した手技といった要素を記録することに重きがおかれていた。こうした活用に加え、学習管理の側面をもたせることも検討可能である。この場合、Moodle等の学習管理システムで取得されることも多い(6)学習時の到達目標、ゴール(7)実際の到達度合い(8)学習を通じて得られた省察といった要素も必要となる。こうした予約・学習管理システムは、次世代の医療シミュレーション教育を実施していくうえでも、学習者と教育者、双方にとって有用となる。(著者抄録)

Laparoscopic surgery requires highly trained skills to manipulate the laparoscopic instruments. The effectiveness and efficiency of manipulation training are expected to increase by quantitatively evaluating how a series of trainee's manipulations are different from those conducted by skilled surgeons and providing feedback. However, such detailed feed- back is not available because adequate measurement systems have not been proposed to measure the precise forces applied to suture training pads without disturbing the delicate manipulations. Therefore, we proposed a sensorized suture training pad satisfying the above requirements. Three surgical residents participated in an experiment to measure time sequences of three-dimensional forces applied to the pad when executing a transfixion suture. As a result, the differences in manipulation patterns among the residents were found by dividing the transfixion operation based on the sequential force data and recorded videos.

BACKGROUND: We developed a surgical knee rest (SKR) that can be used to decrease the stress placed on the lower half of the body when surgeons work in the standing position. We tested the effectiveness of this device in the context of laparoscopic surgery. MATERIAL AND METHODS: Five healthy, right-handed male surgeons participated, and we recorded surface electromyography (sEMG) signals from the two heads of the left and right gastrocnemius (Gc) muscles during laparoscopic resections of colorectal cancer. The outcome variable was the percentage of maximum Gc muscle effort generated, reported as percent maximal isometric voluntary contraction (%MVC), and this variable was compared between surgeries performed with and without use of the SKR. Assessment covered the first 100 min of surgery, subdivided into two 50-min periods. RESULTS: Mean %MVC of the left Gc muscle for the full 100-min test period was significantly decreased when the SKR was used (p = .027, vs. SKR not used). Notably, mean %MVC of both Gc muscles was significantly decreased during the first 50 min of surgery (p = .008 and p = .0046). CONCLUSION: The SKR is useful for decreasing physical stress incurred by laparoscopic surgeons when working in the standing position.

OBJECTIVE: This study aimed to use convolutional neural network (CNN), a deep learning software, to assist in cT1b diagnosis. METHODS: This retrospective study used 190 colon lesion images from 41 cases of colon endoscopies performed between February 2015 and October 2016. Unenhanced colon endoscopy images (520 × 520 pixels) with white light were used. Images included 14 cTis cases with endoscopic resection and 14 cT1a and 13 cT1b cases with surgical resection. Protruding, flat, and recessed lesions were analyzed. AlexNet and Caffe were used for machine learning. Fine tuning of data to increase image numbers was performed. Oversampling for the training images was conducted to avoid impartiality in image numbers, and learning was carried out. The 3-fold cross-validation method was used. Sensitivity, specificity, accuracy, and area under the curve (AUC) values in the receiver operating characteristic curve were calculated for each group. RESULTS: The results were the average of obtained values. With CNN learning, cT1b sensitivity, specificity, and accuracy were 67.5, 89.0, and 81.2%, respectively, and AUC was 0.871. CONCLUSION: Quantitative diagnosis is possible using an endoscopic diagnostic support system with machine learning, without relying on the skill and experience of endoscopists. Moreover, this system could be used to objectively evaluate endoscopic diagnoses.

Background and study aims : Helicobacter pylori (HP)-associated chronic gastritis can cause mucosal atrophy and intestinal metaplasia, both of which increase the risk of gastric cancer. The accurate diagnosis of HP infection during routine medical checks is important. We aimed to develop a convolutional neural network (CNN), which is a machine-learning algorithm similar to deep learning, capable of recognizing specific features of gastric endoscopy images. The goal behind developing such a system was to detect HP infection early, thus preventing gastric cancer. Patients and methods:  For the development of the CNN, we used 179 upper gastrointestinal endoscopy images obtained from 139 patients (65 were HP-positive: ≥ 10 U/mL and 74 were HP-negative: < 3 U/mL on HP IgG antibody assessment). Of the 179 images, 149 were used as training images, and the remaining 30 (15 from HP-negative patients and 15 from HP-positive patients) were set aside to be used as test images. The 149 training images were subjected to data augmentation, which yielded 596 images. We used the CNN to create a learning tool that would recognize HP infection and assessed the decision accuracy of the CNN with the 30 test images by calculating the sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC). Results:  The sensitivity and specificity of the CNN for the detection of HP infection were 86.7 % and 86.7 %, respectively, and the AUC was 0.956. Conclusions:  CNN-aided diagnosis of HP infection seems feasible and is expected to facilitate and improve diagnosis during health check-ups.

Background: Surgical workflow analysis has recently been studied to optimize complex surgical processes and assist in learning of surgical skills. Two important challenges are acquiring detailed task information for the analysis without affecting the surgical environment and deriving comprehensive evaluation of a surgeon's skill and the surgical process based on the task information. Thus, the purpose of this study was to present a comprehensive method for achieving both quantification of a surgeon's skill level and comparative evaluation of the surgical process in laparoscopic surgery on the basis of navigation information only. Material and methods: Laparoscopic cholecystectomy was selected as the target surgery and the task features during the dissecting tasks, which are especially important for the procedure, were parameterized and analyzed. The proposed approach uses these parameters to quantify a surgeon's skill level based on a multiple regression analysis, and to create and compare surgical process models based on a multiple alignment algorithm. Results: A total of 37 procedures of simulated laparoscopic cholecystectomy were analyzed for validation of the proposed approach. From the experimental results, we found that the multiple regression analysis reasonably quantified the surgeons' skill levels, and that the clustering for comparison of the surgical process models reflected the features of surgical performance during the procedure. Conclusions: This study indicates the availability of navigation information for quantitatively evaluating comprehensive surgical performance during laparoscopic surgery.

PURPOSE: By integrating locally operated small surgical robots in a sterilized area, a surgeon can perform safe and accurate robotically assisted laparoscopic surgery. At present, there is no locally operated compact forceps robot that can operate within a small space while providing a wide working area on the abdominal wall. In the present study, a new spherical-coordinate manipulator with a linear telescopic rail and two circular telescopic rails that can act as a third arm for the surgeon has been developed. METHODS: A compact locally operated detachable end-effector manipulator (LODEM) was developed. This manipulator uses circular telescopic rails with linkage mechanisms for the yaw and pitch axes, and a linear telescopic rail for the insertion/extraction axis is attached to forceps. The dimensions of the manipulator are [Formula: see text] when contracted and [Formula: see text] when expanded. The positional accuracy, mechanical deflection, and backlash of the prototype were evaluated while performing simulated in vivo laparoscopic surgery. RESULTS: The positional accuracy, deflection, and backlash of the telescopic rail mechanism were 2.1, 1.8, and 5.1 mm, respectively. The manipulator could successfully handle the target and maintain stability, while the arms of the endoscope specialist were free from collisions with the manipulator during an in vivo laparoscopic surgery. CONCLUSIONS: A compact LODEM was designed to facilitate minimally invasive, robotically assisted laparoscopic surgery by a doctor working near the patient. This device could be used for such applications.

Background and study aims We have developed a combined laparoscopic and luminal endoscopic surgery technique for resection of gastric submucosal tumors (SMTs) that can be performed without excessive resection of the stomach. In a multicenter retrospective study we aimed to evaluate the feasibility and safety of laparoscopic and endoscopic cooperative surgery (LECS) for gastric SMT resection. Patients and methods Between October 2007 and December 2011, 126 patients with gastric SMTs underwent LECS at 8 institutions. Patient demographics, tumor histopathologic characteristics, and operative and follow-up data were reviewed. Results 16 tumors (12.7 %) were located in the upper third of the stomach, 88 (69.8 %) in the middle third, 5 (4.0 %) in the lower third, and 17 (13.5 %) at the esophagogastric junction. The mean (standard deviation [SD]) operation time for LECS was 190.2 (66.8) min, with a mean estimated blood loss of 15.1 (38.6) mL. In 2 cases (1.6 %), the procedure was converted to open surgery because of intra-abdominal adhesions or stenosis. Morbidity was found in 6 cases (4.8 %), including 2 leakage, 2 gastric stasis, 1 fever, and 1 cystitis. Histologically, a gastrointestinal stromal tumor (GIST) was found in 86 (68.3 %) cases. The median follow-up period was 54.7 months; no local or distant tumor recurrence was observed and all patients were alive. Conclusions LECS proved to be a safe and feasible procedure for the resection of gastric SMTs, with a reasonable operation time, low bleeding, and an acceptable complication rate in this multicenter study in Japan.

AIM: To investigate the detrimental impact of loss of reservoir capacity by comparing total gastrectomy (TGRY) and distal gastrectomy with the same Roux-en-Y (DGRY) reconstruction. The study was conducted using an integrated questionnaire, the Postgastrectomy Syndrome Assessment Scale (PGSAS)-45, recently developed by the Japan Postgastrectomy Syndrome Working Party. METHODS: The PGSAS-45 comprises 8 items from the Short Form-8, 15 from the Gastrointestinal Symptom Rating Scale, and 22 newly selected items. Uni- and multivariate analysis was performed on 868 questionnaires completed by patients who underwent either TGRY (n = 393) or DGRY (n = 475) for stage I gastric cancer (52 institutions). Multivariate analysis weighed of six explanatory variables, including the type of gastrectomy (TGRY/DGRY), interval after surgery, age, gender, surgical approach (laparoscopic/open), and whether the celiac branch of the vagus nerve was preserved/divided on the quality of life (QOL). RESULTS: The patients who underwent TGRY experienced the poorer QOL compared to DGRY in the 15 of 19 main outcome measures of PGSAS-45. Moreover, multiple regression analysis indicated that the type of gastrectomy, TGRY, most strongly and broadly impaired the postoperative QOL among six explanatory variables. CONCLUSION: The results of the present study suggested that TGRY had a certain detrimental impact on the postoperative QOL, and the loss of reservoir capacity could be a major cause.

The sidestream dark-field (SDF) imaging allows direct visualization of red blood cells in microvessels near tissue surfaces. We have developed an image-based oximetry method using two-band images obtained by SDF imaging (SDF oximetry) and a trial SDF device with light-emitting diodes to obtain band images. In this study, we propose a technique of producing oxygen saturation (SO2) maps from SDF images and perform animal experiments in vivo. To produce SO2 maps, we use spectral analysis using two band images obtained with our SDF device. As an image processing, the combination of both the Hessian-based and pixel value-based techniques as blood vessel extraction from an SDF image is used. From the experiment with the surface of rat small intestines, we can produce SO2 maps and find that the map represents arterioles and venules those were determined based on the blood ow from SDF images. Moreover, we find the variation of SO2 along a blood vessel running direction.

Background/Aims: Totally laparoscopic distal gastrectomy (TLDG) has become a feasible and safe surgical option for early gastric cancer. However, determining the transection line of the stomach without palpation is still difficult. This study aimed to assess the efficacy of TLDG for gastric resection under retroflexed endoscopic guidance (GRREG) in patients with gastric cancer in the middle third of the stomach. Methods: Fifteen patients with gastric cancer underwent TLDG using GRREG. Preoperative tumor localization using endoscopic metal clips was performed in all cases. After lymphadenectomy, two-thirds of the estimated transection line was occluded by an endoscopic stapler, beginning at the lesser curvature. Under gastric occlusion, the gastroscope was passed via the narrow lumen along the greater curvature followed by retroflexion to reveal the occlusion line, marking clips, and tumor in the same field of view. This view verified the safe oncological transection line. Results: All patients had cancer-free margins and did not require additional surgery. The mean (+/- SD) proximal margin was 23.5 +/- 10.4 mm. There were no procedure-related complications. Conclusions: GRREG was a safe and effective technique for TLDG. Ideal transection of the stomach was achieved using a combination of an endoscopic stapler and gastroscope retroflexion. (C) 2016 S. Karger AG, Basel

The sidestream dark-field (SDF) imaging allows direct visualization of red blood cells in microvessels near tissue surfaces. We have developed an image-based oximetry method using two-band images obtained by SDF imaging (SDF oximetry) and a trial SDF device with light-emitting diodes to obtain band images. In this study, we propose a technique of producing oxygen saturation (SO2) maps from SDF images and perform animal experiments in vivo. To produce SO2 maps, we use spectral analysis using two band images obtained with our SDF device. As an image processing, the combination of both the Hessian-based and pixel value-based techniques as blood vessel extraction from an SDF image is used. From the experiment with the surface of rat small intestines, we can produce SO2 maps and find that the map represents arterioles and venules those were determined based on the blood flow from SDF images. Moreover, we find the variation of SO2 along a blood vessel running direction.

We have previously proposed an estimation method of intravascular oxygen saturation (SO2) from the images obtained by sidestream dark-field (SDF) imaging (we call it SDF oximetry) and we investigated its fundamental characteristics by Monte Carlo simulation. In this paper, we propose a correction method for scattering by the tissue and performed experiments with turbid phantoms as well as Monte Carlo simulation experiments to investigate the influence of the tissue scattering in the SDF imaging. In the estimation method, we used modified extinction coefficients of hemoglobin called average extinction coefficients (AECs) to correct the influence from the bandwidth of the illumination sources, the imaging camera characteristics, and the tissue scattering. We estimate the scattering coefficient of the tissue from the maximum slope of pixel value profile along a line perpendicular to the blood vessel running direction in an SDF image and correct AECs using the scattering coefficient. To evaluate the proposed method, we developed a trial SDF probe to obtain three-band images by switching multicolor light-emitting diodes and obtained the image of turbid phantoms comprised of agar powder, fat emulsion, and bovine blood-filled glass tubes. As a result, we found that the increase of scattering by the phantom body brought about the decrease of the AECs. The experimental results showed that the use of suitable values for AECs led to more accurate SO2 estimation. We also confirmed the validity of the proposed correction method to improve the accuracy of the SO2 estimation.

The purpose of this study was to design an endoscopic dissector handle and objectively assess its usability. The handles were designed with increased contact area between the fingers and thumb and the eye rings, and the eye rings were modified to have a more perpendicular insertion angle to the finger midline. Four different handle models were compared, including a conventional product. Subjects performed dissection, exclusion, grasping, precision manipulation and precision handling tasks. Electromyography and subjective evaluations were measured. Compared to conventional handles, the designated handle reduced the muscle load in the extensor and flexor muscles of the forearm and increased subjective stability. The activity of the first dorsal interosseous muscle was sometimes influenced by the shape of the other parts. The ergonomically designed endoscopic dissector handle used in this study achieved high usability. Medical instrument designs based on ergonomic concepts should be assessed with objective indices.

A male patient in his early seventies complained of swallowing difficulty and back pain. Esophagogastroscopy was performed and the patient was diagnosed as squamous cell carcinoma in the middle and lower part of the esophagus with a longitudinal submucosal elevation of 15 cm and S2 stage of gastric ulcer infected by Helicobacter pylori. Multiple lymph node swelling was detected not only in the mediastinum but also in the neck and the para-aortic area by CT scanning. The clinical stage was T3 N4 M0 Stage IVa. Systemic chemotherapy was applied first and the curative effectiveness was SD based on the RECIST criteria. PET revealed accumulation of FDG in the esophageal and stomach wall. These lesions were suspected to be HP-infected esophageal cancer, and Helicobacter pylori elimination was performed. After HP eradication, the tumor of the esophagus, submucosal elevation of esophagus, and gastric ulcer was markedly shrunk. Multiple lymph node swelling was definitely shrunk based on CT. Overall the early esophageal cancer remained. Endoscopic submucosal dissection (ESD) was performed. The pathological diagnosis was Type 0-IIc, pT1b(SM2), ly1, v2, pHM0, pVM0. After ESD, he indicated febrile neutropenia, was diagnosed as myelodysplastic syndrome (MDS) during the follow-up period and chose best supportive care (BSC).

Background and AimTo demonstrate the effect of endoscopic injection sclerotherapy (EIS) with argon plasma coagulation (APC) as a primary/secondary prophylaxis for esophageal varies (EV) on portal hemodynamics and long-term outcomes in cirrhosis. MethodsThis prospective study included 48 cirrhotic patients (64.511.4years; 26 bleeders, 22 non-bleeders). Post-treatment outcomes (EIS and APC; median observation period, 12.8months for recurrence and 21.1months for prognosis) were evaluated with respect to the findings of hepatic venous catheterization, Doppler ultrasound, and endoscopic ultrasonography (EUS). ResultsAll patients showed EV eradication after endoscopic treatment, and a decreased frequency of a patent left gastric vein (pre: 83.3%, post: 27.1%, P&lt;0.001). However, hepatic venous pressure gradient (HVPG, mmHg) remained unchanged after the treatment, pre: 16.1 +/- 3.6, post: 15.6 +/- 3.8 (P=0.269). Cumulative variceal recurrence/rebleeding rates were 25.5%/5.6% and 62.4%/23.1% at 1 and 3years, respectively. Post-treatment EUS finding, area of submucosal vessels in the cardia 12mm(2) was the only significant factor for variceal recurrence (hazard ratio 9.769, 95% confidence interval 3.046-31.337; P&lt;0.001). Cumulative recurrence rate was significantly higher in patients with area of submucosal vessels in the cardia 12mm(2) (58.3% at 1year and 100% at 3years) than in those without (11.4% at 1year and 40.9% at 3years, P&lt;0.001). Cumulative overall survival rates were 95.2% and 71.9% at 1 and 3years, respectively, showing no significant relationship with HVPG. ConclusionEIS with APC for EV is unlikely to have a significant influence on portal pressure.

Background: Laparoscopic and robot-assisted surgeries are performed under carbon dioxide insufflation. Switching from gas to an isotonic irrigant introduces several benefits and avoids some adverse effects of gas insufflation. We developed an irrigating device and apparatus designed for single-incision laparoscopic surgery and tested its advantages and drawbacks during surgery in a porcine model. Materials and Methods: Six pigs underwent surgical procedures under general anesthesia. A 30-cm extracorporeal cistern was placed over a 5-6-cm abdominal incision. The abdomen was irrigated with warm saline that was drained via a suction tube placed near the surgical field and continuously recirculated through a closed circuit equipped with a hemodialyzer as a filter. Irrigant samples from two pigs were cultured to check for bacterial and fungal contamination. Body weight was measured before and after surgery in four pigs that had not received treatments affecting hemodynamics or causing diuresis. Results: One-way flow of irrigant ensured laparoscopic vision by rinsing blood from the surgical field. Through a retroperitoneal approach, cystoprostatectomy was successfully performed in three pigs, nephrectomy in two, renal excision in two, and partial nephrectomy in one, under simultaneous ultrasonographic monitoring. Through a transperitoneal approach, liver excision and hemostasis with a bipolar sealing device were performed in three pigs, and bladder pedicle excision was performed in one pig. Bacterial and fungal contamination of the irrigant was observed on the draining side of the circuit, but the filter captured the contaminants. Body weight increased by a median of 2.1% (range, 1.2-4.4%) of initial weight after 3-5 hours of irrigation. Conclusions: Surgery under irrigation is feasible and practical when performed via a cistern through a small abdominal incision. This method is advantageous, especially in the enabling of continuous and free-angle ultrasound observation of parenchymal organs. Adverse effects of abdominal irrigation need further assessment before use in humans.

Aim: Dumping syndrome is a well-known adverse outcome after gastrectomy, but the precise clinical features have not been described. The aim of this study was to examine global aspects of dumping syndrome and to explore factors affecting the intensity of dumping syndrome in a large cohort using a newly developed integrated questionnaire, the Post-Gastrectomy Syndrome Assessment Scale (PGSAS)-45. Methods: Eligible questionnaires retrieved from 2,368 patients after 6 types of gastrectomy were analyzed. The incidence, intensity and number of symptoms of early general, early abdominal and late dumping syndrome were examined across various types of gastrectomy, and clinical factors affecting the intensity of each category of dumping syn- drome were identified by multiple regression analysis. Results: Dumping syndromes occurred most frequently and strongly in patients who underwent total gastrectomy with Roux-en-Y (TGRY), followed by proximal gastrectomy (PG), distal gastrectomy with Billroth-I, distal gastrectomy with Roux-en-Y, pylorus-preserving gastrectomy (PPG) and local resection (LR), in that order. Significant positive correlations among different categories of dumping syndromes were observed. TGRY, female sex, younger age, division of the celiac branch of the vagus nerve, PG and shorter postoperative period were independently related to worse dumping syndrome. Conclusions: Dumping syndromes were most common after TGRY and least common after PPG and LR among the various gastrectomy procedures. Type of gastrectomy and several clinical factors were related to the intensity of dumping syndrome. PGSAS-45 could offer a useful tool for evaluating dumping syndrome after gastrectomy. (C) 2015 S. Karger AG, Basel

The optimal surgical procedure for distal gastrectomy with Roux-en-Y reconstruction (DGRY) remains to be determined. Recently, a self-report assessment instrument, the Postgastrectomy Syndrome Assessment Scale-45 (PGSAS-45), was compiled to evaluate symptoms, the living status and the quality of life of patients who have undergone gastrectomy. We used this scale to evaluate procedures used for DGRY. The subjects included 475 patients who underwent DGRY for stage IA/IB gastric cancer. We evaluated whether the size of the remnant stomach, length of the Roux limb, reconstruction route and anastomotic procedure affected the patients' symptoms, living status and quality of life assessed using the PGSAS-45. Patients with a residual stomach of more than half had significantly worse esophageal reflux scores than the patients with a smaller residual stomach (P = 0.0462); a residual stomach of one-third or one-fourth was favorable. A shorter length of the Roux limb was shown to be preferable to a longer Roux limb based on the results of the PGSAS-45. In addition, antecolic reconstruction and the anastomotic procedure using a linear stapler were found to be more favorable. The size of the remnant stomach and the length and route of the Roux limb significantly influence the patient-reported DGRY outcomes.

To compare the results of abdominal wall closure using interrupted synthetic short-term vs. long-term tensile strength-retaining absorbable sutures. The subjects were 55 patients undergoing elective laparotomy through a midline vertical incision for gastric or colon cancer surgery between November 2008 and August 2010, at our hospital. After providing informed consent, the patients were randomized for suturing with Polysorb(A (R)), which provides short-term tensile strength, or with (PDSII)-I-A (R), which provides long-term strength. The primary outcome analyzed was the incidence of incisional hernia or wound dehiscence. There were 28 patients allocated to the Polysorb group and 27 to the PDS II group. Postoperative wound dehiscence was noted in two patients (3.6 %). Five of 51 patients (9.8 %) suffered incisional hernia within 1 year after surgery, 6 of 41 patients (14.6 %) within 2 years, and 6 of 35 patients (17.1 %) within 3 years. There was no significant per year difference in the incidence of incisional hernia or wound dehiscence between the groups. Outcomes were favorable in both groups and not inferior to reported outcomes of larger-scale studies. Verification of the equivalence between the two types of suture material necessitates larger-scale studies that adopt the same suture methods.

We investigate the possibility of oxygen saturation estimation from images obtained by the sidestream dark-field (SDF) technique. The SDF technique is a method for microvascular imaging. In SDF imaging, light enters a tissue directly from illumination sources configured around a camera and then the camera captures the light scattered by the tissue. To advance the capability of the SDF imaging system, we develop a SDF oximetry method with LED illumination sources. In this paper, we evaluate some SDF oximetry methods from virtual SDF images obtained by the Monte Carlo photon propagation simulation. As a result, we verify that SDF imaging allows the estimation of oxygen saturation of the individual vessels from virtual images using the average extinction coefficients considering the bandwidth of the illumination and the effect of the integration of the camera. (C) 2015 Optical Society of America

Pylorus-preserving gastrectomy (PPG) is sometimes performed as a function-preserving surgery for the treatment of early gastric cancer. The aim of this study was to use an integrated assessment scale for postgastrectomy syndrome to determine the appropriate indicators and optimal methods for PPG. The Postgastrectomy Syndrome Assessment Study (PGSAS) is a multicenter survey based on an integrated questionnaire (PGSAS-45) consisting of 45 items. Questionnaire responses were retrieved from a total of 2,520 patients, each of whom had undergone one of six different types of gastrectomy procedures; 313 responses from patients who had received PPG were analyzed here. The size of the proximal gastric remnant (less than one-quarter, about one-third, or more than one-half of the original size) significantly influenced the change in body weight, the scores for dissatisfaction at the meal, and dissatisfaction for daily life subscale (P = 0.030, P = 0.005, P = 0.034, respectively). The nausea score in patients who underwent hand-sewn anastomosis was significantly lower than in those who underwent anastomosis with a linear stapler (P = 0.006). The scores for diarrhea subscale, increased passage of stools, and sense of foods sticking differed significantly depending on the length of the preserved pyloric cuff (P = 0.047, P = 0.021, P = 0.046, respectively). The results suggest that preservation of a sufficient proximal gastric remnant is recommended when utilizing PPG as function-preserving surgery.

This paper presents two features to make neurosurgery with 5-ALA-induced fluorescent imaging more convenient and more reliable. The first one is the concept for a system that switches between white light and excitation light rapidly and allows surgeons to easily locate the tumor region on the normal color image. The second one is the way for color signal processing that yields a stable fluorescent signal without depending on the lighting condition. We developed a prototype system and confirmed that the color image display with the fluorescent region worked well for both the brain of a dead swine and the resected tumor of a human brain. We also performed an experiment with physical phantoms of fluorescent objects and confirmed that the calculated flurophore density-related values were stably obtained for several lighting conditions.

Advanced surgical procedures, which have become complex and difficult, increase the burden of surgeons. Quantitative analysis of surgical procedures can improve training, reduce variability, and enable optimization of surgical procedures. To this end, a surgical task analysis system was developed that uses only surgical navigation information. Division of the surgical procedure, task progress analysis, and task efficiency analysis were done. First, the procedure was divided into five stages. Second, the operating time and progress rate were recorded to document task progress during specific stages, including the dissecting task. Third, the speed of the surgical instrument motion (mean velocity and acceleration), as well as the size and overlap ratio of the approximate ellipse of the location log data distribution, was computed to estimate the task efficiency during each stage. These analysis methods were evaluated based on experimental validation with two groups of surgeons, i.e., skilled and "other" surgeons. The performance metrics and analytical parameters included incidents during the operation, the surgical environment, and the surgeon's skills or habits. Comparison of groups revealed that skilled surgeons tended to perform the procedure in less time and involved smaller regions; they also manipulated the surgical instruments more gently. Surgical task analysis developed for quantitative assessment of surgical procedures and surgical performance may provide practical methods and metrics for objective evaluation of surgical expertise.

Billroth-I (BI) and Roux-en-Y (RY) are well-known reconstruction methods that are conducted following distal gastrectomy. However, the relative merits of these 2 methods are not well documented. The newly developed Postgastrectomy Syndrome Assessment Scale (PGSAS)-45 is an integrated questionnaire consisting of 45 items, including 8 items from the 8-Item Short-Form Health Survey (SF-8), 15 items from the Gastrointestinal Symptom Rating Scale, and 22 items selected by gastric surgeons. Postoperative QOL ratings were evaluated for each reconstruction method using PGSAS-45. The PGSAS-45 questionnaire was distributed to 2,922 patients who underwent gastrectomies at 52 medical institutions. Among the questionnaires distributed, 2520 (86 %) were retrieved and 2368 (81 %) met eligibility requirements. Statistical analyses were conducted to compare 1,384 of the eligible questionnaires, including responses from patients who underwent BI (n = 909) and RY (n = 475) procedures. BI procedures were associated with significantly longer postoperative periods, a significantly greater size of gastric remnants, and a higher frequency of laparoscopic approaches and celiac branch preservation. Postoperative QOL analysis indicated that BI procedures resulted in significantly lower postoperative weight loss and significantly higher esophageal reflux symptoms than RY procedures. There was no significant difference between the two groups on other outcome measures. Although weight loss was significantly lower following BI procedures, esophageal reflux symptoms were significantly higher. Either BI or RY procedures may be recommended based on the individual patient's condition after distal gastrectomy. The newly developed QOL questionnaire, PGSAS-45 and changes in body weight proved useful for evaluation of QOL following gastrectomy.

In laparoscopic surgery, to identify the location of lesions and blood vessels inside organs, an ultrasound probe which can be inserted through small incision is used. However, since surgeons must observe the laparoscopic and ultrasound images both at the same time, it is difficult to understand the correspondence between the ultrasound image and real space. Therefore, to recognize the correspondence between these two images intuitively, we developed a system for overlaying ultrasound image on the laparoscopic image. Since the tip of the probe is flexed freely, we acquired the probe tip position and orientation using a method for detecting the probe angle from laparoscopic image and information obtained from optical tracking sensor. As a result of an experiment using a wire phantom, overlaying error of ultrasound images was found to be 0.97 mm. Furthermore, the rate of probe angle detection was evaluated through an animal experiment to be 83.1%.

In gastrointestinal surgery, surgeon subjectively judges if the organ is healthy from the color. However it is difficult to discriminate a small difference of organ's color by visual inspection. In this paper, we focus on the tissue oxygen saturation (StO(2)) that represents balance of oxygen demand and supply in tissue and try to estimate its value by transmitted light intensity analysis. We developed a system for measurement of transmitted light intensity using a compact spectrometer and a halogen light source and collected transmitted light intensity data from pig's small intestines. Absorbance of the tissue was then calculated from those data. On the basis of Beer-Lambert law, we estimated StO(2) from the calculated absorbance. Results of evaluation experiment to pig's small intestines suggested the possibility of quantitative evaluation of tissue viability by the proposed method.