Many biliary tract surgeons have now reached a level of sophistication with laparoscopic cholecystectomy that they are now able to deal with the common bile duct at the same time. Preoperative endoscopic cholangiography can be reserved for cases where choledocholithiasis has a high degree of probability. This has served to decrease the number of negative studies. The surgeon has five choices regarding stones confirmed by operative cholangiography during laparoscopic cholecystectomy: (1) do nothing, hoping the stones will pass spontaneously or that a postoperative sphincterotomy with stone extraction will be successful; (2) perform a transcystic laparoscopic common bile duct exploration (best for stones less than 1 cm and distal to the cystic duct); (3) perform a laparoscopic common bile duct exploration by choledochotomy (best for large stones in patients with common bile ducts greater than 1 cm. It is also the preferred approach with stones proximal to the insertion of the cystic duct.); (4) perform an intraoperative sphincterotomy with stone extraction, either retrograde or antegrade (this approach has some proponents but has not gained popularity among the majority of surgeons); and (5) place a double lumen catheter through the cystic duct with a proximal lumen in the common bile duct and the distal lumen in the duodenum. This can be used for serial postoperative cholangiography to confirm spontaneous stone passage or falsely positive operative cholangiograms. It is useful in situations when laparoscopic common bile duct exploration equipment or surgeon expertise is not available. If stones persist, a guidewire can be introduced through the distal lumen of the catheter for a guidewire-assisted sphincterotomy. Other CBD interventions that have been reported include laparoscopic biliary bypass and resection of choledochal cysts. Malignant lesions should not be approached by a laparoscopic method except in unusual circumstances.

This paper describes the design of an active gravity balanced planar mechanism, where auxiliary parallelograms are used to physically locate the center of mass of the mechanism. A sliding carriage positions a counterweight directly above the center of mass of the mechanism in order to make the system gravity balanced. The sliding carriage uses joint encoder data from the mechanism to compute the location of the center of mass. Experiment results demonstrate the effectiveness of the approach.

Recent industrial InterestIn the low-temperature high-pressure processing of hydrocarbons has Increased the need for reliable data on the components found In natural gas. The objective of the work reported here is to provide accurate experimental measurements on a system of Industrial Interest and to assess the feasibility of modeling the phase equilibria with simple cubic equations of state. Liquid-vapor equilibria were measured for the binary systems N2 + C2H, and CH4 + C2He and the ternary system N2 + CH4 + C2He at 260.00, 270.00, and 280.00 K over the pressure regions of Industrial Interest. The data at 270.00 K were modeled with three cubic equations of state: the Peng-Roblnson equation, the Soave modification of the Redllch-Kwong equation, and a modified Clausius equation. All of the equations gave satisfactory results at lower pressures, but all failed to model the data satisfactorily near the critical points of the binary and ternary systems.

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Morgagni hernias are unusual diaphragmatic hernias which usually present in adulthood. They have traditionally been repaired through transabdominal or transthoracic approaches. The authors present a case of a laparoscopic repair of a Morgagni hernia in a 52-year-old female. A tension free repair of the defect was accomplished utilizing Goretex (W.L. Gore & Associates, Inc., North Elkton, MD) mesh. The patient had an uneventful recovery and is asymptomatic at 6 months follow-up. The etiology, diagnosis and traditional surgical approaches to this problem are discussed. A technique for laparoscopic repair of a Morgagni hernia is described. The literature on the laparoscopic repair of a Morgagni hernia is reviewed and different operative techniques are discussed.