Early experience of laparoscopic resection and comparison with open surgery for gastric gastrointestinal stromal tumor: a multicenter retrospective study.

The advantages of laparoscopic resection over open surgery in the treatment of gastric gastrointestinal stromal tumor (GIST) are not conclusive. This study aimed to evaluate the postoperative and oncologic outcome of laparoscopic resection for gastric GIST, compared to open surgery. We retrospectively reviewed the prospectively collected database of 1019 patients with gastric GIST after surgical resection at 13 Korean and 2 Japanese institutions. The surgical and oncologic outcomes were compared between laparoscopic and open group, through 1:1 propensity score matching (PSM). The laparoscopic group (N = 318) had a lower rate of overall complications (3.5% vs. 7.9%, P = 0.024) and wound complications (0.6% vs. 3.1%, P = 0.037), shorter hospitalization days (6.68 ± 4.99 vs. 8.79 ± 6.50, P < 0.001) than the open group (N = 318). The superiority of the laparoscopic approach was also demonstrated in patients with tumors larger than 5 cm, and at unfavorable locations. The recurrence-free survival was not different between the two groups, regardless of tumor size, locational favorableness, and risk classifications. Cox regression analysis revealed that tumor size larger than 5 cm, higher mitotic count, R1 resection, and tumor rupture during surgery were independent risk factors for recurrence. Laparoscopic surgery provides lower rates of complications and shorter hospitalizations for patients with gastric GIST than open surgery.

A simple method for removing initial irregularity of an electrocardiogram during a transient state of a power supply in a defibrillator.

BACKGROUND: The defibrillator is a device that instantaneously discharges the high energy stored in the capacitor to the human body to help revitalize the heart. The circuit for charging the capacitor uses the same power source as the biosignal measurement unit. Therefore, variation in main power supply voltage, ground noise, and electromagnetic interference from the charging circuit can induce distortion into the biosignal at the initial stage of charging. OBJECTIVE: In this study, a simple method is proposed for removing the initial irregularity of an electrocardiogram due to the transient state of a power supply. METHODS: To evaluate the method, a 1-channel electrocardiogram measurement unit and peripheral units were separated from the main control module using galvanic isolation. An isolated push-pull converter was designed to power the secondary side. The method was tested under steady-state and transient conditions. RESULTS: The obtained results proved that biosignal distortion can be significantly reduced. CONCLUSION: This method could be another simple implementation approach for solving signal distortions due to the transient status of power supplies used in medical devices.

A simple segmentation and quantification method for numerical quantitative analysis of cells and tissues.

BACKGROUND: Microscopic image analysis based on image processing is required for quantitative evaluation of decellularization. Existing methods are not widely used because of expensive commercial software, and machine learning-based techniques lack generality for decellularization because many high-resolution image data has to be processed. OBJECTIVE: In this study, we developed an image processing algorithm for quantitative analysis of tissues and cells in a general microscopic image. METHODS: The proposed method extracts the color images obtained by the microscope into reference images consisting of grayscale, red (R), green (G), and blue (B) information and transforms each into a binary image. The transformed images were extracted by separating the cells and tissues through outlier noise elimination, logical multiplication and labeling. In order to verify the method, decellularization of porcine arotic valve was performed by the electrical method. Slice samples were obtained by time and the proposed method was applied. RESULTS: The experimental results show that the segmentation of cells and tissues, and quantitative analysis of the number of cells and changes in tissue area during the decellularization process was possible. CONCLUSIONS: The proposed method shows that cell and tissue extraction and quantitative numerical analysis were possible in different brightness of microscopic images.

Long-Term Surgical Outcome of 1057 Gastric GISTs According to 7th UICC/AJCC TNM System: Multicenter Observational Study From Korea and Japan.

The aim of this study was to evaluate the treatment and prognosis of gastric gastrointestinal stromal tumors (GISTs) according to the 7th UICC/AJCC tumor-node-metastasis (TNM) system and the modified National Institutes of Health (NIH) risk classification. The study cohort consisted of 1057 patients with gastric GIST who underwent surgery between January 2000 and December 2007 from 13 institutions in Korea and 2 in Japan. Clinicopathologic characteristics, surgical outcomes, recurrence, and 5-year recurrence-free survival were evaluated.The mean age of the patients was 58.6 years. Thirty patients (2.8%) had distant metastasis preoperatively. Median tumor size was 4.0 cm. Complete resection (R0 resection) was achieved in 1018 patients (96.3%). Eighty-six patients (8.1%) had postoperative complications, and 2 patients (0.2%) died within 30 days after surgery. According to the 7th UICC/AJCC TNM system, 5-year recurrence-free survival rates were 95% to 99% in stage I, 94.1% in stage II, 74.1% in stage IIIA, 48.6% in stage IIIB, and 50.0% in stage IV patients. On survival analysis of high-risk patients according to the TNM system, the 5-year recurrence-free survival rates were 91.6% in stage II, 74.1% in stage IIIA, and 48.6% in stage IIIB patients. Independent factors of recurrence following surgery for gastric GIST were gender, tumor size, mitotic count, and radicality on multivariate analysis.The treatment outcome and prognosis of gastric GIST in Korea and Japan seem more favorable compared to those in Western countries. Compared to the modified NIH risk classification, the 7th UICC/AJCC TNM system is more reflective of the 5-year recurrence-free survival of patients with gastric GIST.

Effect of visceral fat area on outcomes of laparoscopyassisted distal gastrectomy for gastric cancer: subgroup analysis by gender and parameters of obesity.

PURPOSE: The aim of this study was to investigate the impact of the visceral fat area (VFA) of patients with gastric cancer undergoing laparoscopic surgery on operative outcomes such as number of retrieved lymph nodes (LNs) and operative time. METHODS: We retrospectively reviewed the medical records and the CT scans of 597 patients with gastric cancer who underwent laparoscopy assisted distal gastrectomy (LADG) with partial omentectomy and LN dissection (>D1 plus beta). Patients were stratified by gender, VFA, and body mass index (BMI), and the clinicopathologic characteristics and operative outcomes were evaluated. Multiple linear regression analysis was used to assess the effects of VFA and BMI on the number of retrieved LNs and operative time in male and female patients. RESULTS: The mean number of retrieved LNs was significantly decreased for both male and female patients with high VFA. The operative time was significantly longer for both male and female patients with high VFA. The number of retrieved LNs had a statistically significant negative correlation with VFA in both men and women, but not with BMI. The operative time had a statistically significant positive correlation with VFA in men, whereas the operative time had a statistically significant positive correlation with BMI in women. CONCLUSION: The preoperative VFA of male patients with gastric cancer who undergo LADG may affect the number of retrieved LNs and operative time. VFA was more useful than BMI for predicting outcomes of LADG.

How much progress has been made in minimally invasive surgery for gastric cancer in Korea?: a viewpoint from Korean prospective clinical trials.

Gastric cancer is the most common cancer in Korea. Because the incidence of gastric cancer is still high even with early detection and because of developments in surgical instruments and technological advances, minimally invasive surgery has rapidly become an accepted treatment for gastric cancer in Korea. Many Korean gastric surgeons have contributed to the rapid adaptation of minimally invasive surgery for gastric cancer: not only the Korean Laparoscopic Gastrointestinal Surgery Study (KLASS) group, but also other expert surgeons after the 2000s. Thanks to their vigorous efforts involving active learning, education, workshops, academic communications, and international communications with active laparoscopic gastric surgeons in Korea, numerous results and well-designed large-scale clinical studies have been published or are actively ongoing, thus increasing its wide acceptance as an option for gastric cancer. Now, Korea has become one of the leading countries using minimally invasive surgery for the treatment of gastric cancer. This review article will summarize the current status and issues, as well as the clinical trials that have finished or are ongoing, regarding minimally invasive surgery for gastric cancer in Korea.

Risk factors for duodenal stump leakage after gastrectomy for gastric cancer and management technique of stump leakage.

BACKGROUND/AIMS: The goal of this study was to elucidate the risk factors for duodenal stump leakage after gastrectomy for gastric cancer. In addition, the management of duodenal stump leakage is reviewed. METHODOLOGY: From January 2002 through December 2012, 1,195 patients with gastric cancer who underwent gastric R0 resection were enrolled in this study. The clinicopathologic features, postoperative outcomes (i.e., operation time, hospital stay, surgical procedures, method of duodenal stump closure, retrieved lymph nodes), and the risk factors of duodenal stump leakage were analyzed. RESULTS: Of the 1,195 patients, 13 patients (1.1%) suffered duodenal stump leakage. Most of the patients with duodenal stump leakage were male (92.3%). Nine patients underwent a subtotal gastrectomy with Billroth- II or Roux-en-Y anastomosis; the other four patients underwent a total gastrectomy with a Roux-en-Y anastomosis. There were two mortalities. With univariate and multivariate analysis, age was the most predictable factor for duodenal stump leakage (p= 0.034, p=0.044) CONCLUSIONS: Duodenal stump leakage was affected by the age. For older patients who undergo a radical gastrectomy for gastric cancer, the surgeon must pay meticulous attention to the transection and mobilization of the duodenum in order to prevent duodenal stump leakage.

Comprehension of readmission after laparoscopy assisted distal gastrectomy: what are the causes?

PURPOSE: The aim of this study is to evaluate long-term outcomes regarding readmission for laparoscopy-assisted distal subtotal gastrectomy (LADG) compared to conventional open distal subtotal gastrectomy (CODG) for early gastric cancer (EGC). METHODS: Between January 2003 and December 2006, 223 and 106 patients underwent LADG and CODG, respectively, for EGC by one surgeon. The clinicopathologic characteristics, postoperative outcomes, postoperative complications, overall 5-year survival, recurrence, and readmission were retrospectively compared between the two groups. RESULTS: Multiple readmission rate in LADG was significantly less than that in CODG (0.4% vs. 3.8%, P = 0.039), although the readmission rate, reoperation rate after discharge, and mean readmission days were not significantly different between the two groups. Readmission rates of the LADG and CODG groups were 12.6% and 14.2%, respectively. First flatus time and postoperative hospital stay was significantly shorter in the LADG group. However, there was no significant difference in the complication rates between the two groups. Overall 5-year survival rates of the LADG and CODG group were 100% and 99.1% (P = 0.038), respectively. CONCLUSION: Compared to the CODG group, the LADG group has several advantages in surgical short-term outcome and some benefit in terms of readmission in surgical long-term outcome for patients with EGC, even though the oncologic outcome of LADG is similar to that of CODG over 5 years.

Analysis of prognostic factors and outcomes of gastric cancer in younger patients: a case control study using propensity score methods.

AIM: To understand the clinicopathological and prognostic features of gastric cancer in younger and older patients. METHODS: Between January 2002 and December 2008, 1667 patients underwent curative gastric surgery. For comparative purposes, the patients were divided into two groups: younger patients who were less than 40 years old (112 patients), and older patients who were 40 years old and older (1555 patients). In both groups, propensity scoring methods were used to select patients with similar disease statuses. A total of 224 matched cases, with 112 patients in each group, were included in the final analysis. RESULTS: Compared to the older group, the younger group with gastric cancer had a significantly higher percentage of females (P = 0.007), poorly differentiated or signet ring cell carcinoma (P < 0.001), advanced T stage gastric cancer (P = 0.045), and advanced tumor-node-metastasis stage cancer (P = 0.036). The older group with gastric cancer had more comorbidities (P < 0.001). With the exception of the number of lymph node dissection (P < 0.001) and retrieved lymph node (P = 0.010), there were no statistically significant differences between the postoperative outcomes of the two groups. During the follow-up period, there were 19 recurrences in the younger group and 11 recurrences in the older group. The overall five-year survival rates in the younger and older groups were 84.3% and 89.6%, respectively (P = 0.172). There were no significant differences (P = 0.238) in the overall survival of patients with advanced T stage gastric cancer in the two groups, with five-year survival rates of 70.8% in the younger group and 79.5% in the older group. With regard to the age-adjusted survival rate, there was significant difference between the two groups (P = 0.225). CONCLUSION: In spite of aggressive cancer patterns in the younger group with gastric cancer, the younger group did not have a worse prognosis than the older group in our study.

Is the rate of postoperative complications following laparoscopy-assisted gastrectomy higher in elderly patients than in younger patients?

BACKGROUND: With an increase in life expectancy, very elderly patients are presenting with gastric cancer more commonly than ever. The present study retrospectively analyzed the surgical outcomes of laparoscopy-assisted gastrectomy for gastric cancer in the young, elderly, and very elderly age groups. METHODS: The study group consisted of 1,055 patients who underwent laparoscopy-assisted gastrectomy between February 2002 and December 2012. We divided these patients into three groups; group 1 (young age, <65 years), group 2 (elderly age, 65-74 years), and group 3 (very elderly age, ≥75 years). RESULTS: There were statistical differences in the rates of postoperative complications among the three groups (P = 0.008). However, when assessed according to the severity of postoperative complications based on the Clavien-Dindo classification, there was no statistical difference among the three groups (P = 0.562). CONCLUSIONS: Laparoscopy-assisted gastrectomy for gastric cancer can be performed in very elderly patients. In analyzing studies of elderly patients with postoperative complications following the procedure, not only should the rate of postoperative complications be taken into consideration, but also the severity of any postoperative complications.

Readmissions following elective radical total gastrectomy for early gastric cancer: a case-controlled study.

BACKGROUND: Readmission after gastrectomy is one of the factors that reflect quality of life. Therefore, we analyzed the several factors related to readmissions after total gastrectomy for early gastric cancer. METHODS: From January 2002 through December 2009, 102 consecutive patients who underwent radical total gastrectomy for early gastric cancer were enrolled in this study. We evaluated the incidence, cause, time point, and type of treatment for readmission after discharge; we compared the readmission and non-readmission groups in regard to clinicopathologic features and postoperative outcomes. RESULTS: The readmission rate during the five years after total gastrectomy was 22 of 102 (21.6%). The most common cause for readmission was esophagojejunostomy stricture (5 cases). The treatment given for 31 readmissions included 23 conservative therapies, 3 radiologic or endoscopic interventions, and 5 re-operations. No significant differences were detected in the clinicopathologic feature, postoperative outcomes, or 5-year survival rates between the readmission and non-readmission group. No specific risk factor was found to be associated with readmission. CONCLUSION: Although we could not determine a specific risk factor associated with readmission after radical total gastrectomy, prevention of readmission by evaluating the causes and treatments after radical total gastrectomy can improve the patient's quality of life.

The differences in clinicopathological features and prognosis among the subtypes of signet ring cell, mucinous, papillary, and lymphoepithelioma-like carcinoma in advanced gastric cancer.

BACKGROUND/AIMS: There are differing histologic subtypes of gastric cancer. We investigated the clinicopathological features and prognosis of: signet ring cell (SRC), mucinous (MGC), papillary (PGC), and lymphoepithelioma-like (LELC) carcinoma in advanced gastric cancer. METHODOLOGY: One hundred thirty six advanced gastric cancer patients, including 62 SRCs, 43 MGCs, 9 PGCs, and 22 LELCs, who underwent R0 gastrectomy between 2002 and 2013, were retrospectively evaluated. RESULTS: There were significant differences in several clinicopathological features. There were found to be statistical differences in postoperative outcomes in the type of gastrectomy and type of anastomosis (p<0.001 and p<0.001, respectively). In terms of overall survival analysis, there was no statistical survival difference among the subtypes of advanced gastric cancer (p=0.088). However, LELC had a better prognosis than the other groups. CONCLUSIONS: There were some differences in several of the clinicopathological features of the subtypes advanced gastric cancer. Although there were no statistical differences in survival, those with LELC showed a better prognosis than did the other groups. Therefore, the treatment of advanced gastric cancer should be individualized, and prognosis considered, according to the subtype.

In-plane switching of vertically aligned negative liquid crystals for high transmittance and wide viewing angle.

We propose a method for in-plane switching of vertically aligned negative liquid crystals (LCs) for high transmittance and wide viewing angle. By applying an in-plane electric field using a double-layered electrode structure, LC molecules can be rotated by the vertical as well as the in-plane components of the applied field over the entire region so that high transmittance can be achieved. The threshold voltage difference can be obtained simply by varying the electrode structure, which can reduce the off-axis gamma shift in a multidomain vertical alignment LC cell.

Light shutter using dichroic-dye-doped long-pitch cholesteric liquid crystals.

We propose a light shutter device using dichroic-dye-doped liquid crystals (LCs) whose Bragg reflection wavelength is set to be infrared by controlling the pitch of cholesteric liquid crystals (ChLCs). A dye-doped long-pitch ChLC cell is switchable between the dark planar state and the transparent homeotropic state. It has the advantages of high transmittance, low operation voltage, and an easy fabrication process relative to previous LC light shutter devices. The proposed light shutter device is expected to achieve high visibility for transparent organic light-emitting diode displays and emerging smart windows, which can be used in airplanes, cars, and other similar applications.

Long term survival results for gastric GIST: is laparoscopic surgery for large gastric GIST feasible?

BACKGROUND: Recently, laparoscopic resection for relatively small sized gastric gastrointestinal stromal tumors (GISTs) has been widely accepted as minimally invasive surgery. However, no report on the long-term safety and efficacy of this surgery for large sized gastric GISTs has been published to date. METHODS: Between July 1998 and January 2011, 104 consecutive patients who underwent resection for gastric GISTs were enrolled in this retrospective study. We assessed the clinicopathological characteristics, postoperative outcomes, patient survival, and tumor recurrence. RESULTS: Of the 104 patients with gastric GISTs who were included in the study, there were 47 males and 57 females whose mean age was 59.8 years. Sixty-four patients (61.5%) had symptoms associated with tumor. Ten patients included in the group 1, 49 in the group 2, 15 in the group 3a, 9 in the group 5, 14 in the group 6a, and 7 in the group 6b. There was one minor complication and no mortalities. Recurrence was noted in 5 patients, with a median follow-up period of 49.3 months (range, 8.4 to 164.4). The 5-year overall and disease free survival rates of 104 patients were 98.6% and 94.8%, respectively. When comparing large tumor (5-10 cm) between laparoscopic and open surgery, there were statistically differences in age, tumor size, tumor location, and length of hospitalization. There were no statistical differences in the 5-year survival rate between laparoscopic and open surgery for large tumor (5-10cm). CONCLUSION: Laparoscopic surgery is feasible and effective as an oncologic treatment of gastric GISTs. Moreover, laparoscopic surgery can be an acceptable alternative to open methods for gastric GISTs of size bigger than 5 cm.

Dual mode switching of cholesteric liquid crystal device with three-terminal electrode structure.

We propose a cholesteric liquid crystal device with a three-terminal electrode structure that can be operated in both the dynamic and the bistable modes. Fast switching (less than 5 ms) between the planar and the in-plane-field-induced states can be realized by applying an in-plane electric field, and conventional bistable switching between the planar and focal conic states can be realized by applying a vertical electric field.

Endoscopic treatment and risk factors of postoperative anastomotic bleeding after gastrectomy for gastric cancer.

BACKGROUND: Anastomotic leakage, bleeding, and stricture are major complications after gastrectomy. Of these complications, postoperative anastomotic bleeding is relatively rare, but lethal if not treated immediately. METHODS: Of 2031 patients with gastric cancer who underwent radical gastrectomy (R0 resection) between January 2002 and December 2010, postoperative anastomotic bleeding was observed in 7 patients. The clinicopathological features, postoperative outcomes such as surgical procedures, bleeding sites and, methods used to achieve hemostasis, and the risk factors of anastomotic bleeding of these 7 patients were analyzed. RESULTS: Of the 2031 patients, 1613 and 418 underwent distal and total gastrectomy, respectively. The bleeding sites were as follows: Billroth-I anastomosis using a circular stapler (n = 1), Billroth-II anastomosis by manual suture (n = 5), and esophagojejunostomy using a circular stapler (n = 1). All patients were treated with endoscopic clipping or epinephrine injection. There was no further endoscopic intervention or reoperation for anastomotic bleeding. CONCLUSIONS: Postoperative anastomotic bleeding is an infrequent but potentially life-threatening complication. Scrupulous surgical procedures are essential for the prevention of postoperative bleeding, and endoscopy was useful for both the confirmation of bleeding and therapeutic intervention.

Comparative study of laparoscopy-assisted versus open subtotal gastrectomy for pT2 gastric cancer.

PURPOSE: Laparoscopy-assisted distal gastrectomy (LADG) is a widely accepted surgery for early gastric cancer. However, its use in advanced gastric cancer has rarely been studied. The aim of this study is to investigate the feasibility and survival outcomes of LADG for pT2 gastric cancer. MATERIALS AND METHODS: Between January 2004 and December 2009, we evaluated 67 and 52 patients who underwent open distal gastrectomy (ODG) and LADG, respectively, with diagnosis of pT2 gastric cancer. The clinicopathological characteristics, postoperative outcomes, and survival were retrospectively compared between the two groups. RESULTS: There were statistically significant differences in the proximal margin of the clinicopathological parameters. The operation time was significantly longer in LADG than in ODG (207.7 vs. 159.9 minutes). There were 6 (9.0%) and 5 (9.6%) complications in ODG and LADG, respectively. During follow-up periods, tumor recurrence occurred in 7 (10.4%) patients of the ODG and in 4 (7.7%) patients of the LADG group. The 5-year survival rate of ODG and LADG was 88.6% and 91.3% (p=0.613), respectively. In view of lymph node involvement, 5-year survival rates were 96.0% in ODG versus 97.0% in LADG for patients with negative nodal metastasis (p=0.968) and 80.9% in ODG versus 78.7% in LADG for those with positive nodal metastasis (p=0.868). CONCLUSION: Although prospective study is necessary to compare LADG with open gastrectomy for the treatment of advanced gastric cancer, laparoscopy-assisted distal gastrectomy might be considered as an alternative treatment for some pT2 gastric cancer.

Patient perception of natural orifice transluminal endoscopic surgery in an endoscopy screening program in Korea.

PURPOSE: Natural orifice transluminal endoscopic surgery (NOTES) is a new method of accessing intracavitary organs in order to minimize pain by avoiding incisions in the body wall. The aim of this study is to determine patients' acceptance of NOTES in Korea and to compare their views about laparoscopic surgery and NOTES for benign and malignant diseases. MATERIALS AND METHODS: The target number of total subjects was calculated to be 540. The subjects were classified into 18 sub-groups based on age groups, gender, and history of prior surgery. The questionnaire elicited information about demographic characteristics, medical check-ups, diseases, endoscopic and surgical histories, marital status and childbirth, the acceptance of NOTES, and the preferred routes for NOTES. In addition, the subjects chose laparoscopic surgery or NOTES for a hypothetical cholecystectomy and rectal cancer surgery, and responded to questions regarding the acceptable complication rate of NOTES, the appropriate cost of NOTES, and the reason(s) why they did not select NOTES. RESULTS: 486 of 540 patients (90.0%) who agreed to participate in this study completed the questionnaire. NOTES was preferred by the following patients: elderly; a history of treatment due to a disease; having regular check-ups; and a history of an endoscopic procedure (p<0.05). The most preferred route for NOTES was the stomach (67.1%). Eighty-four percent of the patients choosing NOTES responded that the complication rate of the new surgical method should be the same or lower than laparoscopic surgery. Vague anxiety over a new surgical method was the most common reason why NOTES was not selected in benign and malignant diseases (64% and 73%), respectively. CONCLUSION: Patients appear to be interested in the potential benefits of NOTES and would embrace it if their concerns about safety are met. We believe that qualified surgical endoscopists can meet these safety concerns, and that NOTES development has the potential to flourish.

Ultrafast switching of randomly-aligned nematic liquid crystals.

We propose an ultrafast nematic liquid crystal (LC) device without alignment layers, where both the dark and bright states can be realized by applying an electric field. A vertical electric field is applied to vertically align the LCs for the dark state, whereas an in-plane electric field is applied to homogeneously align the LCs for the bright state. We achieved a total response time of less than 3 ms in the proposed device. This device may contribute, not only to a significant improvement of the switching speed in liquid crystal devices, but also to the simplification of the device fabrication by the omission of the alignment layer coating and the rubbing process.