Tele-proctoring for minimally invasive surgery across Japan: An initial step toward a new approach to improving the disparity of surgical care and supporting surgical education.

Aim: The aim of this study was to verify the clinical feasibility of tele-proctoring using our ultra-low latency communication system with shared internet access. Methods: Connections between two multiple remote locations at various distances were established through the TELEPRO® tele-proctoring system. The server records the latency between the two locations for tele-proctoring using the annotations. Questionnaires were administered to the surgeons, assistants, and medical staff. Respondents rated the quickness and quality of communication in terms of latency and disturbances in the audio, video, and usefulness of the live telestrations with annotation. Results: Seven hospitals tele-proctored with Sapporo Medical University between January 2021 and September 2022. The median latency of annotation between the two locations ranged from 24.5 to 48.5 ms. No major technological problems occurred, such as streaming interruption, loss of video or audio, poor resolution. The video encoding time was 10 ms, and its decoding time was 0.8 ms. The total latency positively correlated with the distance between two locations (R = 0.55, p < 0.01). The quality of communication regarding latency, disturbance, and surgical education with intraoperative annotative instructions showed similar trends, with perfectly fine being the most common response. No significant differences in surgical quality, educational effect, or social impact were observed between the latency ≥30 and <30 ms groups for whether the size of latency affects surgical education. Conclusion: The feasibility of the tele-proctoring system is expected to be a sustainable approach to help education for young surgeons and surgical supports in rural areas, thereby reducing disparities in health care.

Current status and future perspectives for the treatment of resectable locally advanced esophagogastric junction cancer: A narrative review.

Incidence rates for esophagogastric junction cancer are rising rapidly worldwide possibly due to the economic development and demographic changes. Therefore, increased attention has been paid to the prevention, diagnosis, and the treatment of esophagogastric junction cancer. Although there are discrepancies in the treatment strategy between Asian and Western countries, surgery remains the mainstay of treatment for esophagogastric junction cancer. Recent developments of perioperative multidisciplinary treatment may lead to better therapeutic effect, higher complete resection rate, and better control of the residual diseases, thus result in prolonged prognosis. In this review, we will focus on the treatment of locally advanced resectable esophagogastric junction cancer, and discuss the current status and future perspectives of the perioperative treatment including chemotherapy, radiation therapy, and immunotherapy, as well as the surgical strategy. Better understanding of the latest treatment strategy and future overlook may enable to standardize and individualize the treatment for esophagogastric junction cancer, thus leading to better prognosis for those patients.

Tele-assessment of bandwidth limitation for remote robotics surgery.

PURPOSE: We investigated the communication bandwidth (CB) limitation for remote robotics surgery (RRS) using hinotori™ (Medicaroid, Kobe, Japan). METHODS: The operating rooms of the Hokkaido University Hospital and Kyushu University Hospital were connected using the Science Information NETwork (SINET). The minimum required CB for the RRS was verified by decreasing the CB from 500 to 100 Mbps. Ten surgeons were tested on a task (intracorporeal suturing) at different levels of video compression (VC) (VC1: 120 Mbps, VC2: 40 Mbps, VC3: 20 Mbps) with the minimum required CB, and assessed based on the task completion time, Global Evaluative Assessment of Robotic Skills (GEARS), and System and Piper Fatigue Scale-12 (PFS-12). RESULTS: Packet loss was observed at 3-7% and image degradation was observed at 145 Mbps CB. The task performance with VC1 was significantly worse than that with VC2 and VC3 according to the task completion time (VC1 vs VC2, P = 0.032; VC1 vs. VC3, P = 0.032), GEARS (VC1 vs VC2; P = 0.029, VC1 vs VC3; P = 0.031), and PFS-12 (VC1 vs. VC2; P = 0.032, VC1 vs. VC3; P = 0.032) with 145 Mbps. CONCLUSION: Our findings provide evidence that RRS using hinotori™ requires a CB ≥ 150 Mbps. We also found that when there is insufficient CB, RRS can be continued by compressing the image.

Development of an intraoperative breast cancer margin assessment method using quantitative fluorescence measurements.

Breast-conserving surgery has become the preferred treatment method for breast cancer. Surgical margin assessment is performed during surgery, as it can reduce local recurrence in the preserved breast. Development of reliable and lower-cost ex vivo cancer detection methods would offer several benefits for patient care. Here, a practical and quantitative evaluation method for the ex vivo fluorescent diagnosis of breast lesions was developed and confirmed through a three-step clinical study. Gamma-glutamyl-hydroxymethyl rhodamine green (gGlu-HMRG) has been reported to generate fluorescence in breast lesions. Using this probe, we constructed a reliable and reproducible procedure for the quantitative evaluation of fluorescence levels. We evaluated the reliability of the method by considering reproducibility, temperature sensitivity, and the effects of other clinicopathological factors. The results suggest that the fluorescence increase of gGlu-HMRG is a good indicator of the malignancy of breast lesions. However, the distributions overlapped. A 5 min reaction with this probe could be used to distinguish at least part of the normal breast tissue. This method did not affect the final pathological examination. In summary, our results indicate that the methods developed in this study may serve as a feasible intraoperative negative-margin assessment tool during breast-conserving surgery.

Functional assessment of miR­1291 in colon cancer cells.

miR­1291 exerts an anti­tumor effect in a subset of human carcinomas, including pancreatic cancer. However, its role in colorectal cancer (CRC) is largely unknown. In the present study, the expression and effect of miR­1291 in CRC cells was investigated. It was identified that miR­1291 significantly suppressed the proliferation, invasion, cell mobility and colony formation of CRC cells. Additionally, miR­1291 induced cell apoptosis. A luciferase reporter assay revealed that miR­1291 directly bound the 3'­untranslated region sequence of doublecortin­like kinase 1 (DCLK1). miR­1291 also suppressed DCLK1 mRNA and protein expression in HCT116 cells that expressed DCLK1. Furthermore, miR­1291 suppressed cancer stem cell markers BMI1 and CD133, and inhibited sphere formation. The inhibitory effects on sphere formation, invasion and mobility in HCT116 cells were also explored and verified using DCLK1 siRNAs. Furthermore, miR­1291 induced CDK inhibitors p21WAF1/CIP1 and p27KIP1 in three CRC cell lines, and the overexpression of DCLK1 in HCT116 cells led to a decrease of p21WAF1/CIP1 and p27KIP1. Intravenous administration of miR­1291 loaded on the super carbonate apatite delivery system significantly inhibited tumor growth in the DLD­1 xenograft mouse model. Additionally, the resultant tumors exhibited significant upregulation of the p21WAF1/CIP1 and p27KIP1 protein with treatment of miR­1291. Taken together, the results indicated that miR­1291 served an anti­tumor effect by modulating multiple functions, including cancer stemness and cell cycle regulation. The current data suggested that miR­1291 may be a promising nucleic acid medicine against CRC.

Development of an x-ray-opaque-marker system for quantitative phantom positioning in patient-specific quality assurance.

PURPOSE: We developed an x-ray-opaque-marker (XOM) system with inserted fiducial markers for patient-specific quality assurance (QA) in CyberKnife (Accuray) and a general-purpose linear accelerator (linac). The XOM system can be easily inserted or removed from the existing patient-specific QA phantom. Our study aimed to assess the utility of the XOM system by evaluating the recognition accuracy of the phantom position error and estimating the dose perturbation around a marker. METHODS: The recognition accuracy of the phantom position error was evaluated by comparing the known error values of the phantom position with the values measured by matching the images with target locating system (TLS; Accuray) and on-board imager (OBI; Varian). The dose perturbation was evaluated for 6 and 10 MV single-photon beams through experimental measurements and Monte Carlo simulations. RESULTS: The root mean squares (RMSs) of the residual position errors for the recognition accuracy evaluation in translations were 0.07 mm with TLS and 0.30 mm with OBI, and those in rotations were 0.13° with TLS and 0.15° with OBI. The dose perturbation was observed within 1.5 mm for 6 MV and 2.0 mm for 10 MV from the marker. CONCLUSIONS: Sufficient recognition accuracy of the phantom position error was achieved using our system. It is unnecessary to consider the dose perturbation in actual patient-specific QA. We concluded that the XOM system can be utilized to ensure quantitative and accurate phantom positioning in patient-specific QA with CyberKnife and a general-purpose linac.

Current status of site-specific cancer registry system for the clinical researches: aiming for future contribution by the assessment of present medical care.

BACKGROUND: The current status of site-specific cancer registry has not been elucidated, but sufficient system is found in some societies. The purpose of this study was to clear the present condition of site-specific cancer registries in Japan and to suggest for the improvement. METHODS: The questionnaire was conducted by the study group of the Ministry of Health, Labor, and Welfare. It consisted of 38 questions, conflicts of interest, clinical research method, informed consent and funding for registry. We distributed this questionnaire to 28 academic societies, which had published the clinical practice guideline(s) assessed under Medical Information Network Distribution Service (MINDS). RESULTS: The concept of the importance in assessment for medical quality by the data of the site-specific cancer registry was in good consensus. But the number of the society with the mature registry was limited. The whole-year registry with the scientific researches in the National Clinical Database (NCD) and in the Translational Research Informatics Center (TRI) might seem to be in success, because assured enhancement may be estimated. Now, academic societies have the structural factors, i.e., the financial limitation in the registry maintenance and the data analysis, and in the difficulty of employment of the researchers with skill and talent. CONCLUSIONS: To manage the site-specific cancer registry effectively, the scientific registry system will be essentially important. Each academic society had much experienced highly qualified clinical researches in past. Accordingly, the scientific suggestion and co-operation should be of great importance for the improvement.

Biliary Stricture: The Achilles Heel of Pediatric Living Donor Liver Transplantation.

Since a 1989 report demonstrating successful living donor liver transplantation (LDLT), living donors have been increasingly used to overcome the disparity between organ supply and demand, especially in the cases of pediatric patients. Although short-term graft outcomes after LDLT have improved significantly because of progress in surgical techniques and immunosuppression, biliary stricture (BS) remains the Achilles heel of pediatric LDLT and is the major cause of significant long-term morbidity. BS results in poor quality of life or even in graft loss after LDLT, with a reported incidence of BS after pediatric LDLT of 10% to 35%. The suggested risk factors for BS after LDLT are hepatic arterial thrombosis, bile duct ischemia, acute cellular rejection, older donor age, and ABO incompatibility. Duct-to-duct biliary reconstruction, which enables an endoscopic approach to be attempted after BS, is the preferred technique for LDLT. Endoscopic approaches are less invasive and more convenient for recipients than surgical and percutaneous interventions. However, the major cause of end-stage liver disease in pediatric recipients is biliary atresia, and hepaticojejunostomy is needed to reconstruct the bile duct because of the lack of recipient bile duct. Endoscopic approaches for BS are usually less favorable in patients with hepaticojejunostomy than in those with duct-to-duct biliary reconstruction. Treatment options for BS after hepaticojejunostomy at many centers thus involve interventional radiology or surgical reintervention. Although endoscopic approaches remain controversial in pediatric recipients, several reports have shown them to be safe and less invasive.

Factors predictive of high-output ileostomy: a retrospective single-center comparative study.

PURPOSE: High-output syndrome (HOS) is a complication of ileostomy, which can affect quality of life significantly; however, its exact cause remains unknown. The aim of this study was to establish the frequency, as well as the preoperative and intraoperative factors predictive of HOS. METHODS: The subjects of this study were 164 consecutive patients who underwent colorectal cancer surgery with ileostomy construction at our institute between January, 2011 and August, 2018. Thirteen patients with postoperative complications reported as causes of HOS, including intraperitoneal abscess, paralytic ileus, and outlet obstruction, were excluded. We used a logistic regression analysis to identify the factors predictive of HOS. RESULTS: HOS developed in 36 of the 151 patients (23.8%). There were significantly more diabetic patients in the HOS group (P = 0.03), but other patient factors such as age, gender, body mass index, and use of daily laxatives were not significantly different between the groups. The HOS group had significantly more cases of total proctocolectomy (P = 0.04), but other surgical factors such as operative time, and blood transfusion were not significantly different between the two groups. CONCLUSIONS: These results indicate that diabetes and total proctocolectomy are preoperative predictors of HOS, allowing for the possibility of early intervention via post-surgical treatment.

Risk assessment of morbidities after right hemicolectomy based on the National Clinical Database in Japan.

OBJECTIVE: Nationwide databases are expected to provide critical data to improve medical practice. The present study used such data to develop risk models for clinically important outcomes after right hemicolectomy based on preoperative risk factors. METHODS: Japan's National Clinical Database (NCD) identified 38 030 cases of right hemicolectomy in the years 2011 and 2012. These were used to analyze correlations between mortality and eight selected clinical outcomes of interest by Pearson's correlation coefficient (r). To construct risk models for the eight selected clinical outcomes, 80% of all the examined cases were extracted randomly as a development cohort, and preoperative risk factors for each clinical outcome were identified using a forward stepwise selection method. Morbidities predicted from the risk models were used to find areas under the receiver operator curves among the remaining 20% of the testing cohort. RESULTS: The following clinical outcomes were identified as highly associated with operative mortality: systemic sepsis (r = .360), renal failure (r = .341), unplanned intubation (r = .316) and central nervous system (CNS) occurrences (r = .301). Risk models containing up to 21 preoperative variables were constructed for these eight postoperative clinical outcomes. Predictive values of the eight models were as follows: surgical site infections (0.634), anastomotic leakage (0.656), systemic sepsis (0.816), pneumonia (0.846), unplanned intubation (0.838), renal failure (0.883), CNS occurrences (0.833) and transfusion >5 units (0.846). CONCLUSIONS: This study indicated that the NCD-generated risk models for six of the eight selected critical postoperative outcomes had high discrimination among right hemicolectomy patients. These risk models can accurately identify high-risk patients prior to surgery.

Assessment potential of a new suture simulator in laparoscopic surgical skills training.

BACKGROUND: The skills necessary for performing effective laparoscopic suturing are difficult to acquire; as a result, simulators for learning these skills are rapidly becoming integrated into surgical training. The aim of the study was to verify whether a new hybrid simulator has the potential to measure skill improvement in young, less experienced gastroenterological surgeons. MATERIAL AND METHODS: The study included 12 surgeons (median age, 29 (27-38)] years; 11 men (91.7%), one woman (8.3%)) who participated in a two-day laparoscopic training seminar. We used the new simulator before and after the program to evaluate individual performance. Skills were evaluated using five criteria: volume of air pressure leakage, number of full-thickness sutures, suture tension, wound area, and performance time. RESULTS: Air pressure leakage was significantly higher after than before the training (p = .027). The number of full-thickness sutures was significantly higher post-training (p < .01). Suture tension was significantly less post-training (p = .011). Wound opening areas were significantly smaller post-training (p = .018). Performance time was significantly shorter post-training (p = .032). CONCLUSIONS: Our study demonstrated the assessment quality of this new laparoscopic suture simulator.

Prediction of Postoperative Complications Following Elective Surgery in Elderly Patients with Colorectal Cancer Using the Comprehensive Geriatric Assessment.

AIMS: The study aims to determine whether the Comprehensive Geriatric Assessment (CGA) could predict complications of colorectal cancer (CRC) surgery and identify the problems. So we compared the prognostic value of the CGA with patient characteristics and determined predictive scores. METHODS: A total of 156 patients aged 75 years and older, who underwent surgery for CRC at Osaka University Hospital, were enrolled. Each patient was examined by the CGA prospectively, and all postoperative complications were obtained from the medical records. The CGA included the Barthel Index (BI), Vitality Index, instrumental activities of daily living (iADL), Mini-Mental State Examination (MMSE) and Geriatric Depression Score (GDS). All elements were retrospectively compared in patients with or without postoperative complications, including delirium, surgical site infection and ileus. RESULTS: Overall, postoperative complications developed in 76 patients (48.7%). The BI and MMSE were associated with the incidence of complications, and BI, iADL, MMSE and GDS were significantly related with delirium. Multivariate logistic analysis identified the MMSE as a significant determinant of postoperative complications after adjusting for other determined predictive scores including the prognostic nutritional index and performance status. CONCLUSION: The CGA was a useful predictor of postoperative complications in elderly patients when administered before surgery for CRC.

Risk Evaluation of Postoperative Delirium Using Comprehensive Geriatric Assessment in Elderly Patients with Esophageal Cancer.

BACKGROUND: The number of geriatric patients with esophageal cancer is increasing in step with the aging of the population. Geriatric patients have a higher risk of postoperative complications, including delirium that can cause a fall or impact survival. Therefore, it is very important that we evaluate risks of postoperative complications before surgery. The aim of this study was to predict postoperative delirium in elderly patients. METHODS: We retrospectively reviewed the medical records of 91 patients aged 75 years and over who underwent esophagectomy between January 2006 and December 2014. We investigated the association between postoperative delirium and clinicopathological factors, including comprehensive geriatric assessment (CGA). RESULTS: Postoperative delirium developed in 24 (26 %) patients. Postoperative delirium was significantly associated with low mini-mental state examination (MMSE) and high Geriatric Depression Scale 15 (GDS15), which are components of CGA, and psychiatric disorder (P < 0.0001, P = 0.002, and P = 0.017, respectively). With multiple logistic regression analysis, MMSE (odds ratio [OR], 1.4; 95 % confidence interval [CI], 1.2-1.6; P < 0.0001] and GDS15 (OR, 1.3; 95 % CI, 1.1-1.6; P = 0.004) were independently associated with postoperative delirium. CONCLUSIONS: Preoperative CGA, especially MMSE and GDS15, was useful for predicting postoperative delirium in elderly patients undergoing esophagectomy for esophageal cancer. Intervention by a multidisciplinary team using CGA might help prevent postoperative delirium.

Comprehensive Geriatric Assessment is a useful predictive tool for postoperative delirium after gastrointestinal surgery in old-old adults.

AIM: To determine whether carrying out the Comprehensive Geriatric Assessment before operations would be useful for predicting complications, particularly postoperative delirium (POD), in old-old patients. METHODS: A total of 517 patients aged 75 years and older, who underwent radical surgery for gastrointestinal cancer at Osaka University Hospital, were recruited for this observational study. The Comprehensive Geriatric Assessment components and assessment of performance status were carried out before surgery, and a record of postoperative complications including POD was made prospectively until discharge from hospital. The following morphological and clinical measurements were also obtained from the medical records: age, sex, disease type, previous history, comorbid lifestyle-related diseases, POD, postoperative complications, operative method, duration of operation, hemorrhage volume, blood transfusion volume, method of anesthesia, body mass index and blood tests. RESULTS: POD appeared in 24.0% of the 517 patients who underwent surgery. Barthel Index, Mini-Mental State Examination, instrumental activities of daily living and Geriatric Depression Scale results were associated with the incidence of POD, and the Barthel Index, Mini-Mental State Examination and Instrumental Activities of Daily Living results were extracted as independent factors associated with the development of POD after adjusting for traditional risk factors for postoperative complications and performance status. CONCLUSIONS: The Comprehensive Geriatric Assessment before gastrointestinal surgery can be a useful tool for predicting the development of POD in old-old patients. Geriatr Gerontol Int 2016; 16: 1036-1042.

Gasless transumbilical laparoscopic-assisted appendectomy as a safe and cost-effective alternative surgical procedure for mild acute appendicitis.

PURPOSE: Several reports have demonstrated the effectiveness and feasibility of single incisional transumbilical laparoscopic-assisted appendectomy (TULAA). We developed a modified TULAA technique, gasless-TULAA, which involves lifting the abdominal wall with a retractor, without pneumoperitoneum or another incision. METHODS: We assessed the surgical outcomes of 257 patients treated for appendicitis in our hospital between 2005 and 2013. In a preoperative comprehensive evaluation, appendicitis without abscess was defined as mild appendicitis (mild appendicitis group: MAG), and appendicitis with abscess was defined as severe appendicitis (severe appendicitis group: SAG). The clinical outcomes were compared with those in other published reports. The cost-effectiveness of gasless-TULAA was compared with that of conventional multiport laparoscopic appendectomy (CMLA) in our hospital. RESULTS: In MAG (n = 228), the operation time and postoperative hospital stay were 46.9 ± 22.7 min and 2.6 ± 1.2 days, respectively. The gasless-TULAA was completed without trocars in 91.2 % of patients. The surgical outcomes of SAG were significantly worse than those of MAG (p < 0.001). The surgical cost of gasless-TULAA was significantly lower than that of CMLA (p < 0.001). CONCLUSION: Gasless-TULAA is a cost-effective, safe, and readily available surgical technique for mild appendicitis, which can obviate the need for specialized equipment.

Feasibility of single-port laparoscopic surgery for sigmoid colon and rectal cancers and preoperative assessment of operative difficulty.

PURPOSE: Single-port laparoscopic surgery is more difficult for sigmoid colon and rectal cancers than for right-sided colon cancer. We sought to analyze the feasibility of this procedure for sigmoid colon and rectal cancers and to estimate its difficulty. METHODS: We analyzed prospectively collected data from 63 consecutive patients with sigmoid colon or rectal cancers who underwent single-port laparoscopic surgery at our institution from June 2009 to December 2011. Patient and tumor characteristics, including patients' pelvic anatomy which was assessed on CT scan imaging, were evaluated to elucidate what factors would affect the difficulty of the procedure and the necessity of using an additional trocar. RESULTS: Overall, the median operative duration was 190 min and blood loss was 20 ml, with no postoperative complications. The median number of lymph nodes harvested was 17 and the distal margin was 58 mm. The tumor was located significantly closer to the anus in cases in which an additional trocar was required in the right lower quadrant (9.5 vs 18 cm, p < 0.0001). Procedural difficulty was significantly increased in cases in which the sacral promontory protruded ventrally (odds ratio 0.779 [95% confidence interval 0.613 to 0.945], p = 0.0236). CONCLUSIONS: Depending on tumor location and sacral promontory shape, the introduction of an additional trocar might render single-port laparoscopic surgery feasible for sigmoid colon and rectal cancer resection.

Risk model for right hemicolectomy based on 19,070 Japanese patients in the National Clinical Database.

BACKGROUND: Right hemicolectomy is a very common procedure throughout the world, although this procedure is known to carry substantial surgical risks. The present study aimed to develop a risk model for right hemicolectomy outcomes based on a nationwide internet-based database. METHODS: The National Clinical Database (NCD) collected records on over 1,200,000 surgical cases from 3,500 Japanese hospitals in 2011. After data cleanup, we analyzed 19,070 records regarding right hemicolectomy performed between January 2011 and December 2011. RESULTS: The 30-day and operative mortality rates were 1.1 and 2.3 %, respectively. The 30-day mortality rates of patients after elective and emergency surgery were 0.7 and 6.0 %, respectively (P < 0.001). The odds ratios of preoperative risk factors for 30-day mortality were: platelet <50,000/µl, 5.6; ASA grade 4 or 5, 4.0; acute renal failure, 3.2; total bilirubin over 3 mg/dl, 3.1; and AST over 35 U/l, 3.1. The odds ratios for operative mortality were: previous peripheral vascular disease, 3.1; cancer with multiple metastases, 3.1; and ASA grade 4 or 5, 2.9. Sixteen and 26 factors were selected for risk models of 30-day and operative mortality, respectively. The c-index of both models was 0.903 [95 % confidence interval (CI) 0.877-0.928; P < 0.001] and 0.891 (95 % CI 0.873-0.908; P < 0.001), respectively. CONCLUSION: We performed the first reported risk stratification study for right hemicolectomy based on a nationwide internet-based database. The outcomes of right hemicolectomy in the nationwide population were satisfactory. The risk models developed in this study will help to improve the quality of surgical practice.

Proposal for a sub-classification of hepato-biliary-pancreatic operations for surgical site infection surveillance following assessment of results of prospective multicenter data.

BACKGROUND: Surgical site infection (SSI) surveillance in Japan is based on the National Nosocomial Infection Surveillance system, which categorizes all hepato-biliary-pancreatic surgeries, except for cholecystectomy, into "BILI." We evaluated differences among BILI procedures to determine the optimal subdivision for SSI surveillance. METHODS: We conducted multicenter SSI surveillance at 20 hospitals. BILI was subdivided into choledochectomy, pancreatoduodenectomy, hepatectomy, hepatectomy with biliary reconstruction, pancreatoduodenectomy with hepatectomy, distal pancreatectomy and total pancreatectomy to determine the optimal subdivision. The outcome of interest was SSI. Univariate and multivariate analyses were performed to determine the predictive significance of variables in each type of surgery. RESULTS: 1,926 BILI cases were included in this study. SSI rates were 23.2 % for all BILI; for choledochectomy 23.6 %, pancreatoduodenectomy 39.3 %, hepatectomy 12.8 %, hepatectomy with biliary reconstruction 41.9 %, pancreatoduodenectomy with hepatectomy 27.3 %, distal pancreatectomy 31.8 %, and total pancreatectomy 20.0 %. SSI rates for hepatectomy were significantly lower than those for non-hepatectomy BILI. Risk factors for developing SSI with hepatectomy were drain placement and long operative duration, while for non-hepatectomy BILI, risk factors were use of intra-abdominal silk sutures, SSI risk index and long operative duration. CONCLUSIONS: Hepatectomy and non-hepatectomy BILI differ with regard to the incidence of and risk factors for developing SSI. These surgeries should be assessed separately when conducting SSI surveillance.

Assessment of COPD severity by combining pulmonary function tests and chest CT images.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitations. Physicians frequently assess the stage using pulmonary function tests and chest CT images. This paper describes a novel method to assess COPD severity by combining measurements of pulmonary function tests (PFT) and the results of chest CT image analysis. METHODS: The proposed method utilizes measurements from PFTs and chest CT scans to assess COPD severity. This method automatically classifies COPD severity into five stages, described in GOLD guidelines, by a multi-class AdaBoost classifier. The classifier utilizes 24 measurements as feature values, which include 18 measurements from PFTs and six measurements based on chest CT image analysis. A total of 3 normal and 46 abnormal (COPD) examinations performed in adults were evaluated using the proposed method to test its diagnostic capability. RESULTS: The experimental results revealed that its accuracy rates were 100.0 % (resubstitution scheme) and 53.1 % (leave-one-out scheme). A total of 95.7 % of missed classifications were assigned in the neighboring severities. CONCLUSIONS: These results demonstrate that the proposed method is a feasible means to assess COPD severity. A much larger sample size will be required to establish the limits of the method and provide clinical validation.