Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Alan Kawarai Lefor has a total of 1000 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Letter to: The use of Bakri balloon to reduce the anastomosis tension in hepaticojejunostomy: An exchange between surgery and obstetrics/gynecology

    by Shigeki Matsubara, Alan Lefor

    Letter to: The use of Bakri balloon to reduce the anastomosis tension in hepaticojejunostomy: An exchange between surgery and obstetrics/gynecology - Turkish Journal of Surgery

  • Changes in thoracic radio density after living donor liver transplantation

    by Atsushi Miki, Yasunaru Sakuma, Yukihiro Sanada, Jun Watanabe, Yasuharu Onishi, Noriki Okada, Toshio Horiuchi, Takahiko Omameuda, Takumi Teratani, Alan K. Lefor, et al.

    Background: The outcomes after liver transplantation have greatly improved, which has resulted in greater focus on improving non‐hepatic outcomes of liver transplantation. The present study aimed to evaluate thoracic spine radio density in children and adolescents after liver transplantation.Methods: A total of 116 patients who underwent living donor liver transplantation were retrospectively analyzed. The radio density at the eleventh thoracic vertebra was measured using computed tomography scan performed preoperatively then annually for 5 years postoperatively and subsequently every 2 or 3 years.Results: The mean thoracic radio density of male recipients of male grafts had the lowest values during the study. The radio density of patients receiving a graft from a female donor was higher than in recipients with grafts from males. Total mean radio density decreased for first 5 years postoperatively and then increased. Changes in radio density were equally distributed in both steroid withdrawal and no steroid withdrawal groups for 5 years, after which patients with steroid withdrawal had a greater increase. Changes in radio density were equally distributed in both the steroid withdrawal and no steroid withdrawal groups up to age 20, after which patients in the steroid withdrawal group had a greater increase.Conclusions: Gender differences may affect the outcome of radio density changes after transplantation. Given the moderate association between thoracic radio density and bone mineral density in skeletally mature adults and further studies are needed to validate this relationship between thoracic radio density and bone mineral density changes in pediatric liver transplantation.


  • Open Access

    Naldemedine is associated with earlier defecation in critically ill patients with opioid-induced constipation: A retrospective, single-center cohort study

    by Seiya Nishiyama, Shigehiko Uchino, Yusuke Sasabuchi, Tomoyuki Masuyama, Alan Kawarai Lefor, Masamitsu Sanui

    There are few reports describing the association of naldemedine with defecation in critically ill patients with opioid-induced constipation. The purpose of this study was to determine whether naldemedine is associated with earlier defecation in critically ill patients with opioid-induced constipation. In this retrospective cohort study, patients admitted to the Intensive Care Unit (ICU) without defecation for 48 hours while receiving opioids were eligible for enrollment. The primary endpoint was the time of the first defecation within 96 hours after inclusion. Secondary endpoints included presence of diarrhea, duration of mechanical ventilation, ICU length of stay, ICU mortality, and in-hospital mortality. The Cox proportional hazard regression analysis with time-dependent covariates was used to evaluate the association naldemedine with earlier defecation. A total of 875 patients were enrolled and were divided into 63 patients treated with naldemedine and 812 patients not treated. Defecation was observed in 58.7% of the naldemedine group and 48.8% of the no-naldemedine group during the study (p = 0.150). The naldemedine group had statistically significantly prolonged duration of mechanical ventilation (8.7 days vs 5.5 days, p < 0.001) and ICU length of stay (11.8 days vs 9.2 days, p = 0.001) compared to the no-naldemedine group. However, the administration of naldemedine was significantly associated with earlier defecation [hazard ratio:2.53; 95% confidence interval: 1.71–3.75, p < 0.001]. The present study shows that naldemedine is associated with earlier defecation in critically ill patients with opioid-induced constipation.


  • Clinical features and distribution of the APC variant in duodenal and ampullary polyps in patients with familial adenomatous polyposis: a multicenter retrospective cohort study in Japan

    by Yasuyuki Miyakura, Tatsuro Yamaguchi, Alan Kawarai Lefor, Sawako Tamaki, Akinari Takao, Misato Takao, Yoshiko Mori, Kenichi Chikatani, Hideyuki Ishida, Mitsuhiro Kono, et al.

    Background Management of duodenal or ampullary adenomas in patients with familial adenomatous polyposis (FAP) is a major challenge for clinicians. Insufficient data are available to evaluate the clinical manifestations and distribution of adenomatous polyposis coli (APC) variants in these patients. Methods We enrolled 451 patients with data regarding duodenal or ampullary polyps from 632 patients with FAP retrospectively registered in a nationwide Japanese multicenter study. Clinicopathological features and distribution of APC variants were compared between patients with and without duodenal or ampullary polyps. Results Duodenal and ampullary polyps were found in 59% and 18% of patients with FAP, respectively. The incidence of duodenal cancer was 4.7% in patients with duodenal polyps, and that of ampullary cancer was 18% in patients with ampullary polyps. Duodenal polyps were significantly associated with the presence of ampullary polyps and jejunal/ileal polyps. Duodenal polyps progressed in 35% of patients with a median follow-up of 776 days, mostly in those with early Spigelman stage lesions. Ampullary polyps progressed in 50% of patients with a follow-up of 1484 days. However, only one patient developed a malignancy. The proportion of patients with duodenal polyps was significantly higher among those with intermediate- or profuse-type APC variants than attenuated-type APC variants. The presence of duodenal polyps was significantly associated with ampullary and jejunal/ileal polyps in patients with intermediate- or profuse-type APC variants. Conclusions Periodic endoscopic surveillance of the papilla of Vater and small intestine should be planned for patients with FAP with duodenal polyps.


  • Open Access

    Repeat bidirectional double-balloon enteroscopy 1 year later may be proper in Peutz-Jeghers patients with difficult-to-reach polyps

    by Yohei Funayama, Kunihiko Oguro, Hirotsugu Sakamoto, Tomonori Yano, Jun Owada, Takuma Kobayashi, Yusuke Ono, Alan Kawarai Lefor, Hironori Yamamoto

    Background and study aims Small-bowel polyps in patients with Peutz–Jeghers syndrome (PJS) are sometimes difficult to reach using double-balloon enteroscopy (DBE). However, they can induce intussusception, especially when ≧15 mm. This study aimed to review the outcomes of patients with such polyps. Patients and methods All patients with PJS with small-bowel polyps that bidirectional DBE failed to reach and were ≧5 mm as shown by DBE enterography at our institution from May 2006 to April 2022 were retrospectively evaluated. The endpoint was the earliest occurrence of symptomatic intussusception induced by the polyp, endoscopic removal by repeat DBE or intraoperative endoscopy, or the last medical record describing the patient’s condition. Results This study included 27 polyps in 13 patients. All patients had extraluminal adhesions. None developed symptomatic intussusception, eight patients underwent endoscopic removal at repeat DBE without surgery, two patients underwent removal with intraoperative endoscopy, two patients were observed without polyp removal, and one patient had a polyp removed at repeat DBE and three unreachable polyps remained. Repeat DBE without surgery was able to remove 14 polyps (52%). Polyps ≧15 mm included 11 lesions in eight patients and were observed for a median of 14 months without symptomatic intussusception. Conclusions The difficult-to-reach polyps may have a low risk of immediate symptomatic intussusception, possibly due to limited bowel mobility by extraluminal adhesions, and the likelihood of reaching them at repeat DBE was substantial. Hence, repeat DBE 1 year later may be proper in such patients with PJS.


  • Open Access

    Remnant liver function is associated with long-term survival in patients with hepatocellular carcinoma undergoing hepatectomy

    by Atsushi Miki, Yasunaru Sakuma, Jun Watanabe, Kazuhiro Endo, Hideki Sasanuma, Takumi Teratani, Alan Kawarai Lefor, Atsushi Shimizu, Joji Kitayama, Yoshikazu Yasuda, et al.

    It is important to assess the prognosis and intervene before and after surgery in patients with hepatocellular carcinoma. This study aims to elucidate the association of outcomes and residual liver function after hepatectomy. A total of 176 patients who underwent the initial resection for hepatocellular carcinoma between January 2011 and March 2021 at Jichi Medical University were included. Hepatic clearance of the remnant liver was measured using 99mTc-galactosyl serum albumin scintigraphy. The log-rank test was used to analyze survival using the Kaplan–Meier method. Hazard ratios (HR) and 95% confidence intervals (CI) for overall survival were calculated using Cox’s proportional hazard model. In multivariate analysis, microvascular invasion, intraoperative blood loss, and hepatic clearance of the remnant liver were independently associated with overall survival. Hepatic clearance of the remnant liver was independently associated with recurrence free survival. This is the first report to show that lower residual liver function is associated with shorter survival in patients with hepatocellular carcinoma undergoing hepatectomy. Preoperative determination of remnant liver function may allow assessment of prognosis in patients planned to undergo resection of hepatocellular carcinoma. Preservation of liver functional reserve may be crucial for improved long-term outcomes after hepatectomy.


  • Open Access

    Survival and revival of surgical procedures

    by Shigeki Matsubara, Alan Kawarai Lefor


  • Open Access

    Pseudocysts and Walled‐Off Necrosis After Acute Pancreatitis

    by Naohiro Sata, Masaru Koizumi, Alan Kawarai Lefor

  • Open Access

    Laparoscopic sleeve gastrectomy followed by laparoscopic adrenalectomy for patients with obesity and primary aldosteronism: Report of two patients

    by Masayuki Shinoda, Shin Saito, Hideki Sasanuma, Yoshinori Hosoya, Alan Kawarai Lefor, Naohiro Sata

    Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Surgical treatment of unilateral PA usually resolves excessive aldosterone secretion. Obesity is an independent factor for postoperative persistent hypertension for patients with unilateral PA. Laparoscopic sleeve gastrectomy has become popular due to its efficacy in resolving obesity. A specific strategy might to be needed for patients with unilateral PA and obesity. Two males with PA and obesity (Body Mass Index: BMIs of 35.9 and 39.0, respectively) were referred for evaluation. Both patients had hypertension caused by PA and obesity. We performed laparoscopic sleeve gastrectomy (LSG) prior to adrenalectomy to avoid persistent postoperative hypertension and perioperative obesity related comorbidities. LSG could lead to decreasing of BMIs to 27.7 and 32.1. Comorbidities associated with obesity were also resolved in both patients. Laparoscopic adrenalectomy was then safely performed in these two patients with PA. Patients with PA developing resistant hypertension were estimated to be 20 % of those who underwent adrenalectomy. Decreased BMI can be an independent preoperative determinant for successful outcome after adrenalectomy regarding hypertension. We need to review with special care the preoperative BMI and the nature of hypertension before performing surgery on patients with unilateral PA. A successful strategy was used to treat two obese patients with unilateral PA who underwent laparoscopic adrenalectomy after LSG to minimize complications associated with obesity-related comorbidities.


  • Open Access

    Endoscopic submucosal dissection of gastric neoplasms with severe fibrosis using a new thin-therapeutic endoscope and a dedicated conical cap

    by Yoshimasa Miura, Hisashi Fukuda, Takashi Ueno, Yoshikazu Hayashi, Hiroyuki Osawa, Alan Kawarai Lefor, Hironori Yamamoto

    Recently, endoscopic submucosal dissection (ESD) using the pocket-creation method (PCM) has been developed as a kind of third space endoscopy. PCM enables complete dissection under the lesion before making the circumferential incision [1]. Using this method, a wide submucosal space should be created with a small entrance where a small-diameter endoscope is more desirable. A few endoscopists reported ESD using ultrathin endoscopy, but disadvantages for such a procedure have been discussed. Although the accessory channels of existing ultrathin endoscopes (EG-L580NW7, Fujifilm Co., Tokyo, Japan) have a diameter of 2.4 mm, some ESD devices such as the knife and coagulation forceps cannot be inserted through the channel because of their larger diameter [2]. The EG-840TP (Fujifilm Co.) was newly developed for endoscopic treatment as a relatively thin endoscope that has an outer diameter of only 7.9 mm but an accessory channel diameter as large as 3.2 mm ([Fig. 1]). It also has a down angle function up to 160 degrees. A calibrated, small-caliber-tip, transparent hood (CAST hood; TOP, Tokyo, Japan) was designed to perform balloon dilation of small intestinal strictures [3]. It is transparent with a 4-mm tip diameter that can be used in ESD. PCM combined with this hood may be more effective in cases with gastric neoplasms accompanied by fibrosis [4]. We present a patient with gastric cancer with fold convergence that recurred after ESD, located in the posterior wall of the middle gastric body. ESD was performed using the PCM with the EG-840TP and a dedicated conical cap (prototype CAST hood), resulting in successful complete resection. Such a therapeutic approach is expected not only to allow precise dissection of severely fibrotic tissue but also to improve endoscopic maneuverability even in a narrow submucosal pocket with severe fibrosis ([Video 1]). This endoscope may be used for third space endoscopy especially in a narrow space. Video 1 The procedure for the pocket-creation method with an EG-840TP and a dedicated conical cap for early gastric cancer. Endoscopy_UCTN_Code_TTT_1AO_2AG Article published online: 13 July 2023 © 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany