Analysis of Blind Reconstruction of BCH Codes.

In this paper, the theoretical lower-bound on the success probability of blind reconstruction of Bose-Chaudhuri-Hocquenghem (BCH) codes is derived. In particular, the blind reconstruction method of BCH codes based on the consecutive roots of generator polynomials is mainly analyzed because this method shows the best blind reconstruction performance. In order to derive a performance lower-bound, the theoretical analysis of BCH codes on the aspects of blind reconstruction is performed. Furthermore, the analysis results can be applied not only to the binary BCH codes but also to the non-binary BCH codes including Reed-Solomon (RS) codes. By comparing the derived lower-bound with the simulation results, it is confirmed that the success probability of the blind reconstruction of BCH codes based on the consecutive roots of generator polynomials is well bounded by the proposed lower-bound.

Roux Stasis Syndrome and Gastric Food Stasis After Laparoscopic Distal Gastrectomy with Uncut Roux-en-Y Reconstruction in Gastric Cancer Patients: A Propensity Score Matching Analysis.

BACKGROUND: Uncut Roux-en-Y gastrojejunostomy (uRYGJ) was developed to prevent slow peristalsis in the Roux limb after Roux-en-Y gastrojejunostomy (RYGJ). This study compared the incidence of Roux stasis syndrome (RSS) and severe gastric food stasis in gastric cancer patients who underwent RYGJ or uRYGJ after laparoscopic curative distal gastrectomy. METHODS: Between January 2006 and June 2012, 319 patients underwent RYGJ or uRYGJ. After covariates were adjusted by propensity score matching, 39 patients in the RYGJ group and 65 patients in the uRYGJ group were included in the final analysis. RSS was defined as the presence of symptoms, such as nausea, vomiting, and abdominal fullness, requiring refasting without ileus or obstruction within 30 days post-surgery. Gastric food stasis was measured endoscopically at 1 and 3 years after gastrectomy. RESULTS: Operative outcomes and morbidities were similar between the two groups, whereas the incidence of RSS was higher in the RYGJ group than in the uRYGJ group, although the difference was not significant (7.7 vs. 0%; odds ratio (OR) 0.157; 95% confidence interval (CI) 0-1.059, p = 0.111). Comparison of endoscopic findings revealed that severe gastric stasis 1 year after surgery was significantly less frequent in the uRYGJ group (46.2 vs. 13.8%; OR 0.247; 95% CI 0.102-0.599, p = 0.002). The same result was reproduced 3 years after surgery (39.4 vs. 15.5%; OR 0.279; 95% CI 0.088-0.882, p = 0.030). CONCLUSIONS: Compared with RYGJ, uRYGJ after laparoscopic distal gastrectomy is a safe and effective procedure for preventing severe postoperative gastric food stasis.

The learning curve associated with laparoscopic total gastrectomy.

BACKGROUND: Although the frequency of laparoscopic total gastrectomy (LTG) has been increasing, the procedure requires considerable experience because of its technical difficulty and the concern for oncological safety. This study intended to define the learning curve associated with the procedure. METHODS: All 256 cases of LTG performed from June 2003 to December 2012 were enrolled. The cases were divided into ten groups of 25 cases based on when they occurred. The learning curve was defined using the moving average method. LTG, performed in the absence of other procedures (pure-LTG, 132 cases), was extracted from the ten groups, and the mean operative time and estimated blood loss (EBL) were compared to define the learning curve. Retrieved lymph nodes, hospital stay, and complications were compared across the phases of the learning curve. LTG with spleen resection, performed in the absence of other procedures (pure-srLTG, 53 cases), was also analyzed by the same method. RESULTS: A three-phase learning curve of LTG was defined: the first two groups, the following two groups, and the final six groups (mean operative time: 223.0, 244.8, and 207.8 min, respectively, p = 0.003; mean EBL: 94.6, 237.0, and 116.5 ml, respectively, p < 0.001). The rates of complications and open conversions were similar across the three phases. There were no significant differences in mean operative time, EBL, retrieved LNs, hospital stay, or complication rates between pure-LTG and pure-srLTG, after completing the respective learning curves. CONCLUSIONS: Experience with approximately 100 LTG cases was required to complete learning of the procedure.

Is a robotic system really better than the three-dimensional laparoscopic system in terms of suturing performance?: comparison among operators with different levels of experience.

BACKGROUND: High-quality three-dimensional (3D) vision systems are now available for laparoscopic surgery and may improve surgical performance relative to two-dimensional (2D) laparoscopy. It is unclear whether 3D laparoscopy is superior to 3D robotic systems. The effect of surgeon experience on surgical performance with different instruments also remains unclear. This study compared the ability of experienced and inexperienced surgeons to perform a suturing task with 2D laparoscopy, 3D laparoscopy, and a 3D robot. METHODS: The 20 recruited surgeons consisted of experts (≥100 laparoscopic cases, n = 9), surgeons with intermediate experience (20-99 cases, n = 7), and novices (<20 cases, n = 4). All performed a suturing task three times with each instrument. Task failure rates and completion times were measured. RESULTS: All novices failed to complete the task with 2D or 3D laparoscopy, but all completed the task with the robot. The intermediate group failed the task with 2D laparoscopy (23.8% failure rate) more often than with 3D laparoscopy (4.8%) or the robot (0%; P = 0.04). Expert failure rates were low for all instruments. Intermediate group task completion times were similar to 2D laparoscopy (median 312 s; range 229-495 s), 3D laparoscopy (324 s; 170-443 s), and the robot (319 s; 213-433 s) (P = 0.237). The expert times differed significantly (P = 0.01); post hoc analyses showed that their total completion time with 3D laparoscopy (177 s; 126-217 s) was significantly shorter than with 2D laparoscopy (244 s; 155-270 s; P = 0.004). It also tended to be shorter than with the robot (233 s; 187-461 s; P = 0.027). CONCLUSIONS: Novices benefited particularly from the robot. The intermediate group completed the task equally well and equally quickly with 3D laparoscopy and the robot. The experts completed the task equally well regardless of instrument, but their times were much faster with 3D laparoscopy. Thus, well-trained laparoscopic surgeons may not really benefit from 3D robot systems if 3D laparoscopy is available.

Feasibility of hyperthermic pressurized intraperitoneal aerosol chemotherapy in a porcine model.

BACKGROUND: Peritoneal carcinomatosis is an unmet therapeutic need. Several types of intraperitoneal chemotherapy have been introduced. However, hyperthermic intraperitoneal chemotherapy has limited drug distribution and poor peritoneal penetration. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) does not have the benefits of hyperthermia. We developed a device to apply hyperthermic PIPAC (H-PAC) and evaluated its feasibility in a porcine model. METHODS: The device for H-PAC consisted of a laparoscopic aerosol spray and a heater to create hyperthermic capnoperitoneum. We operated on five pigs for the development of the new device and on another five pigs as a survival model. After a pilot experiment of the survival model (Pig A), a hyperthermic pressurized intraperitoneal aerosol of indocyanine green was administered after insertion of three trocars (Pig B) and laparoscopy-assisted distal gastrectomy (LADG) (Pig C) without chemotherapeutic agents. After that, H-PAC with cisplatin was administered after insertion of three trocars (Pig D) and LADG (Pig E). Autopsies were performed on postoperative day 7. RESULTS: Median operation time was 85 min (80-110 min). Intraperitoneal temperature was constant for 1 h of H-PAC (38.8-40.2 °C). All five pigs were healthy and survived for 7 days. Median weight loss was 0.2 kg. Autopsy tissues of stomach, peritoneum, and jejunum were intact in all five pigs. CONCLUSIONS: H-PAC was feasible and safe in a porcine model.

Eleven-year experience with 3000 cases of laparoscopic gastric cancer surgery in a single institution: analysis of postoperative morbidities and long-term oncologic outcomes.

BACKGROUND: The present study summarizes the 11-year laparoscopic gastric cancer surgery experience of a single institution in South Korea and evaluates the current trends of laparoscopic gastric cancer surgery through our experience. METHODS: A total of 3000 minimally invasive gastric cancer surgeries were performed at Seoul National University Bundang Hospital between May 2003 and January 2014. The types of laparoscopic gastrectomy used, surgical techniques, postoperative morbidities, and long-term oncologic outcomes were analyzed. RESULTS: The proportion of challenging procedures such as laparoscopic total gastrectomy and laparoscopic gastrectomy for patients with advanced gastric cancer increased during the study period. The frequency of laparoscopic function-preserving gastrectomy for patients with early-stage cancer also increased. The overall rate of complications was 16.7 %; surgical and systemic complication rates were 11.8 and 6.2 %, respectively. There was one case of postoperative mortality due to delayed bleeding after discharge. Male gender, high BMI, long operating times, combined resection of other organs, and total and proximal gastrectomies were independent predictors of surgical morbidities; however, pathologic T-stage was not a predictable factor. Accumulated experience in laparoscopic surgery decreased the surgical complication rates of total and proximal gastrectomies more than it did in distal gastrectomy over time. The 5-year overall survival rates of patients in advanced stages and those who underwent laparoscopic total gastrectomy were comparable to those reported previously. CONCLUSIONS: Our results indicate the trends toward the expansion of laparoscopic approaches to technically demanding procedures and an increased use of laparoscopic function-preserving surgeries for patients with EGC with acceptable outcomes.

Rapid Staining Using the Shorr Method for Intraoperative Peritoneal Washing Cytology in Advanced Gastric Cancer: a Pilot Study from a Single Institution.

PURPOSE: Intraoperative peritoneal washing cytology (PWC) is used to determine treatment strategies for gastric cancer with suspected serosal invasion. However, a standard staining method for intraoperative PWC remains to be established. We evaluated the feasibility of a rapid and simple staining method using Shorr's stain for intraoperative PWC in advanced gastric cancer. MATERIALS AND METHODS: Between November 2012 and December 2014, 77 patients with clinical T3 or higher gastric cancer were enrolled. The sensitivity, specificity, and concordance between the Shorr staining method and conventional Papanicolaou (Pap) staining with carcinoembryonic antigen (CEA) immunohistochemistry (IHC) were analyzed. RESULTS: Intraoperative PWC was performed laparoscopically in 69 patients (89.6%). The average time of the procedure was 8.3 minutes, and the average amount of aspirated fluids was 83.3 mL. The average time for Shorr staining and pathologic review was 21.0 minutes. Of the 77 patients, 16 (20.7%) had positive cytology and 7 (9.1%) showed atypical findings; sensitivity and specificity were 73.6% and 98.2% for the Shorr method, and 78.9% and 98.2% for the Pap method with CEA IHC, respectively. Concordance of diagnosis between the 2 methods was observed in 90.9% of cases (weighted κ statistic=0.875) and most disagreements in diagnoses occurred in atypical findings (6/7). In overall survival, there was no significant difference in C-index between the 2 methods (0.459 in Shorr method vs. 0.458 in Pap with CEA IHC method, P=0.987). CONCLUSIONS: Shorr staining could be a rapid and reliable method for intraoperative PWC in advanced gastric cancer.

Spleen-preserving lymphadenectomy versus splenectomy in laparoscopic total gastrectomy for advanced gastric cancer.

BACKGROUND: To investigate the optimal approach for laparoscopic splenic hilum lymph node dissection in proximal advanced gastric cancer, we compared the operative outcomes between laparoscopic spleen-preserving total gastrectomy (sp-LTG) and laparoscopic total gastrectomy with splenectomy (sr-LTG). METHODS: A retrospective case-cohort study was conducted between February 2006 and December 2012. The operative outcomes, the number of retrieved splenic hilum lymph node, complication, and patients' survivals were analyzed. RESULTS: 112 patients who underwent laparoscopic total gastrectomy with or without splenectomy for advanced gastric cancer were enrolled (68 sp-LTGs and 44 sr-LTGs). The mean operation time (227 min vs. 224 min, p = 0.762), estimated blood loss (157 ml vs. 164 ml, p = 0.817), and complication rate (17.6% vs. 13.6%, p = 0.572) were not different between two groups. Regarding splenic lymph node dissection, there were significantly differences in the mean number of retrieved lymph nodes between sp-LTG and sr-LTG (LN no.10; 1.78 vs. 3.21, p = 0.033, LN no.11d; 1.41 vs. 2.76, p = 0.004). The 5-year survivals were 77.3% in sp-LTG and 65.9% in sr-LTG (p = 0.240). The hazard ratio of splenectomy was 1.139 (95% confidence interval 0.514-2.526, p = 0.748). CONCLUSION: In laparoscopic total gastrectomy for proximal advanced gastric cancer, spleen-preserving hilar dissection showed comparable short-term and long-term outcomes.

An extension and test of Sutherland's concept of differential social organization: the geographic clustering of Japanese suicide and homicide rates.

In an effort to explain the spatial patterning of violence, we expanded Sutherland's (1947) concept of differential social organization to include the level of deviance exhibited by neighboring areas. To test the value of this extension, the geographic clustering of Japanese suicide and homicide rates is assessed using 1985 and 1995 data for prefectures. Univariate results show that both types of violence cluster significantly in space. Inconsistent with the proposed expansion of differential social organization, multivariate results show that proximity to homicide does not increase the risk of homicide in Japan. Results for suicide are supportive and suggest that proximity to higher rates of suicide exposes residents to cultural values that support suicide and to role models who have committed suicide.

Solo Intracorporeal Esophagojejunostomy Reconstruction Using a Laparoscopic Scope Holder in Single-Port Laparoscopic Total Gastrectomy for Early Gastric Cancer.

Single-incision laparoscopic total gastrectomy for gastric cancer has recently been reported by Seoul National University Bundang Hospital. However, this is not a popular procedure primarily because of the technical difficulties involved in achieving consistent intracorporeal esophagojejunostomy. At Seoul National University Bundang Hospital, we recently introduced a simple, easy-to-use, low-profile laparoscopic manual scope holder that enables the maintenance of a stable field of view, the most demanding condition in single-port gastrectomy. In this technical report, we describe in detail the world's first solo single-incision laparoscopic total gastrectomy with D1+ lymph node dissection and intracorporeal esophagojejunostomy for proximal early gastric cancer.