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Hirasawa Y.,Tokyo Medical University | Ohno Y.,Tokyo Medical University | Nakashima J.,Tokyo Medical University | Shimodaira K.,Tokyo Medical University | And 5 more authors.
Surgical Endoscopy and Other Interventional Techniques | Year: 2015

Background: To assess the impact of preoperatively estimated prostate volume (PV) using transrectal ultrasonography (TRUS) on surgical and oncological outcomes in robot-assisted radical prostatectomy (RARP). Methods: We analyzed the experience of a single surgeon at our hospital who performed 436 RARPs without neoadjuvant hormone therapy between August 2006 and December 2013. Patients were divided into three groups according to their preoperative PV calculated using TRUS (PV ≤ 20 cm3: group 1, n = 61; 20 < PV < 50 cm3: group 2, n = 303; PV ≥ 50 cm3: group 3, n = 72). Results: Blood loss was significantly higher in group 3 than in group 1 and group 2. In stage pT2 patients, the rate of positive surgical margin (PSM) was significantly lower in group 3 than in group 1. In addition, perioperative complications significantly increased with increasing PV, while the extraprostatic extension (EPE) rate significantly decreased with increasing PV. The preoperative biopsy Gleason score, prostate-specific antigen (PSA) density, and clinical T2 stage were inversely correlated with increasing PV. Biochemical recurrence-free survival after RARP was significantly lower in group 1 than in groups 2 and 3. Conclusions: A large prostate size was significantly associated with increased blood loss and a higher rate of perioperative complications. A small prostate size was associated with a higher PSM rate, PSA density, Gleason score, EPE rate, and biochemical recurrence rate. These results suggest that RARP was technically challenging in patients with large prostates, whereas small prostates were associated with unfavorable oncological outcomes. © 2015 Springer Science+Business Media New York Source


Nakata Y.,Teikyo University | Yoshimura T.,Shin Yurigaoka General Hospital | Watanabe Y.,Teikyo University | Otake H.,Showa University | And 2 more authors.
International Journal of Health Care Quality Assurance | Year: 2015

Purpose – The purpose of this paper is to examine whether the current surgical reimbursement system in Japan reflects resource utilization after the revision of fee schedule in 2014. Design/methodology/approach – The authors collected data from all the surgical procedures performed at Teikyo University Hospital from April 1 through September 30, 2014. The authors defined the decision-making unit as a surgeon with the highest academic rank in the surgery. Inputs were defined as the number of medical doctors who assisted surgery, and the time of operation from skin incision to closure. An output was defined as the surgical fee. The authors calculated surgeons’ efficiency scores using data envelopment analysis. Findings – The efficiency scores of each surgical specialty were significantly different ( p=0.000). Originality/value – This result demonstrates that the Japanese surgical reimbursement scales still fail to reflect resource utilization despite the revision of surgical fee schedule. © Emerald Group Publishing Limited. Source


Nakata Y.,Teikyo University | Watanabe Y.,Teikyo University | Narimatsu H.,Kanagawa Cancer Center Research Institute | Yoshimura T.,Shin Yurigaoka General Hospital | And 2 more authors.
International Journal of Health Care Quality Assurance | Year: 2016

Purpose – The sustainability of the Japanese healthcare system is in question because the government has had a huge fiscal debt. Despite an enormous effort to cut the deficit, our healthcare expenditure is increasing every year because of the rapidly aging population. One of the solutions for this problem is to improve the productivity of healthcare. The purpose of this paper is to determine the factors that change surgeons’ productivity in one year. Design/methodology/approach – The authors collected data of all surgical procedures performed at Teikyo University Hospital from April 1 through September 30 in 2014 and 2015, and computed the surgeons’ Malmquist index (MI), efficiency change (EC) and technical change (TC) using non-radial and non-oriented Malmquist model under the constant returns-to-scale assumptions. The authors then divided the surgeons into two groups; one whose productivity progressed and the other whose productivity regressed. These two groups were compared to identify factors that may influence their MI. Findings – The only significant difference between the two groups was ECs (p<0.0001). The other factors, such as TC, experience, surgical volume, emergency cases, surgical specialty, academic ranks, medical schools and gender, were not significantly different between the two groups. Originality/value – EC is a major determinant of surgeons’ productivity change. The best way to improve surgeons’ productivity may be to enhance their efficiency regardless of their surgical volume and personal backgrounds. © 2016, © Emerald Group Publishing Limited. Source


Nakata Y.,Teikyo University | Yoshimura T.,Shin Yurigaoka General Hospital | Watanabe Y.,Teikyo University | Otake H.,Showa University | And 2 more authors.
Operations Research for Health Care | Year: 2016

The goal of this study is to evaluate Japanese surgeons' productivity change before and after the revision of fee schedule.We focused on the revision of fee schedule that was implemented on April 1, 2014. We analyzed all the surgical procedures performed from April 1 through September 30 in 2013 and 2014 at Teikyo University Hospital. Non-radial and non-oriented Malmquist model under the constant returns-to-scale assumptions was employed. Inputs were defined as the number of medical doctors who assisted surgery, and the time of surgical operation from skin incision to skin closure. The output was defined as the surgical fee for each surgery. We computed each surgeon's natural logarithms of Malmquist index, efficiency change and technical change.We analyzed 5,315 surgical procedures performed by 108 surgeons. The productivity change was not significantly different from 0 (. p=. 0.230). However, the efficiency change was significantly positive (. p=. 0.041) while the technical change was significantly negative (. p<. 0.0001).Surgeons' productivity did not significantly change after the revision of fee schedule because surgeons performed surgery more efficiently to compensate for their reduced reimbursements. © 2016 Elsevier Ltd. Source


Sugiyama N.,Japan National Institute of Infectious Diseases | Murayama A.,Japan National Institute of Infectious Diseases | Suzuki R.,Japan National Institute of Infectious Diseases | Watanabe N.,Japan National Institute of Infectious Diseases | And 4 more authors.
PLoS ONE | Year: 2014

The hepatitis C virus (HCV) culture system has enabled us to clarify the HCV life cycle and essential host factors for propagation. However, the virus production level of wild-type JFH-1 (JFH-1/wt) is limited, and this leads to difficulties in performing experiments that require higher viral concentrations. As the cell culture-adapted JFH-1 has been reported to have robust virus production, some mutations in the viral genome may play a role in the efficiency of virus production. In this study, we obtained cell culture-adapted virus by passage of full-length JFH-1 RNA-transfected Huh-7.5.1 cells. The obtained virus produced 3 log-fold more progeny viruses as compared with JFH-1/wt. Several mutations were identified as being responsible for robust virus production, but, on reverse-genetics analysis, the production levels of JFH-1 with these mutations did not reach the level of cell culture-adapted virus. By using the single strain isolation method by end-point dilution and infection, we isolated two strains with additional mutations, and found that these strains have the ability to produce more progeny viruses. On reverse-genetics analysis, the strains with these additional mutations were able to produce robust progeny viruses at comparable levels as cell culture-adapted JFH-1 virus. The strategy used in this study will be useful for identifying strains with unique characteristics, such as robust virus production, from a diverse population, and for determining the responsible mutations for these characteristics. Source

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