Exploring ideal operative time for best outcomes in gastric cancer surgery:A multi-institutional study based on KLASS-07 database

Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.

Comparison of different nutritional assessments in detecting malnutrition among gastric cancer patients

AIM: To evaluate the prevalence of preoperative and postoperative malnutrition and the relationships between objective and subjective nutritional assessment of gastric cancer patients. METHODS: From October 2005 to July 2006, we studied 80 patients with no evidence of recurrent disease and no loss to follow-up after curative surgery for gastric cancer. In this group, 9 patients underwent total gastrectomy and 71 patients subtotal gastrectomy. At admission, 6 and 12 mo after surgery, the patients were assessed on the subjective global assessment (SGA), nutritional risk screening (NRS-2002), nutritional risk index (NRI) and by anthropometric measurements and laboratory data. Differences between the independent groups were assessed with the Student's t test and oneway analysis of variance. Spearman's rank correlation coefficients were calculated to evaluate the association between the scores and variables. RESULTS: The prevalence of malnutrition at admissionwas 31% by SGA and 43% by NRS-2002. At admission, the anthropometric data were lower in the malnourished groups defined by the SGA and NRS-2002 assessments, but did not differ between the groups using the NRI assessment. Body weight (BW), body mass index (BMI), triceps skin fold and midarm circumference were significantly reduced, but the total lymphocyte count, albumin, protein, cholesterol and serum iron levels did not decrease during the postoperative period. Six months after surgery, there was a good correlation between the nutritional assessment tools (SGA and NRS-2002) and the other nutritional measurement tools (BW, BMI, and anthropometric measurements). However, 12 mo after surgery, most patients who were assessed as malnourished by SGA and NRS-2002 had returned to their preoperative status, although their BW, BMI, and anthropometric measurements still indicated a malnourished status. CONCLUSION: A combination of objective and subjective assessments is needed for the early detection of the nutritional status in case of gastric cancer patients after gastrectomy.

Design,Fabrication,and Analysis of Flapping and Folding Wing Mechanism for a Robotic Bird

Emulating periodic main wing movement of a bird for generating lift and thrust remains a significant challenge in developing a robotic bird.The sequences of main wing motion are comprised of flapping,folding,bending,and twisting.In this paper,we concentrate on the flapping and folding motion,and design two wing mechanisms based on a 4-bar linkage structure:one is only for Flapping Motion(FM)and the other is for simultaneous Flapping and Folding Motion(FFM)during a wing stroke.We derive relationships between length and angle of links to analyze kinematic characteristics of the mechanisms and conduct an optimization to select the length parameters of links that allow maximization of the flapping angle.We run a simulation to confirm the performance of the optimized parameters by examining physical properties,and fabricate two wing mechanisms accordingly.In particular,the folding motion is achieved without using an additional actuator.Force measurements to investigate a lift profile of each mechanism and their quantitative comparison of the performance of both types confirm the benefits of the folding motion in the perspectives of wing frequency and lift.We expect that our kinematic formulation,design procedures,and comparative measurement results can help develop a wing mechanism to create a truly biomimetic robotic bird.