Minimally invasive removal of gallstones

All of these techniques depend on the percutaneous puncture of the gallbladder and the removal of stones either mechanically or by dissolution. Some procedures can be performed under local anaesthesia, others require general anaesthesia, but none requires a conventional surgical incision. Mechanical removal of the stones, with or without crushing, can be achieved under direct vision after dilating the percutaneous track to the gallbladder, in a similar fashion to percutaneous nephrolithotomy. After removing all the stones attempts have been made to obliterate the gallbladder lumen by instilling drugs such as tetracycline.

 

Many chemicals have been tested for their ability to dissolve gallstones and a few of them are clinically useful. Methyl tert-butyl ether is an alkyl ether that rapidly dissolves cholesterol. It smells unpleasant and causes vomiting and sedation if it is absorbed; the catheter should take a transhepatic route to the gallbladder to minimize the possibility of intraperitoneal leakage. Small volumes of methyl tert-butyl ether, which will not overflow into the bile duct, are then instilled and aspirated cyclically until the stones have dissolved.

 

The stone recurrence rate following either procedure has not yet been assessed but there is no reason to think that it will be any different to the results following dissolution with oral therapy.

 

Extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy was first introduced for the management of renal calculi and has subsequently been adapted for fragmentation of both gallbladder and common bile duct stones. Once again the stones should be radiolucent and the gallbladder must function so that the tiny fragments of stone can pass spontaneously. Adjuvant oral dissolution therapy is required concurrently. The stones should be less than 30 mm in diameter and there should not be more than three (ideally only one). These criteria restrict the use of extracorporeal shock wave lithotripsy to between 5 per cent and 10 per cent of patients.

 

Shock waves are generated either by a spark gap system, a piezoelectric generator, or by the electromagnetic deflection of a metal membrane. They are then synchronized with the r wave of the electrocardiogram and focused on to the gallstone, which is imaged using either ultrasound or X-rays. With modern piezoelectric machines the treatment is virtually painless, even though more than one treatment and several thousand shocks may be required. Cutaneous petechiae, transient haematuria, and mild pancreatitis are recognized complications, and about one-third of patients experience biliary colic. Oral treatment with stone-dissolving drugs needs to continue, but in one reported series by the end of 2 years after extracorporeal shock wave lithotripsy the gallbladder was empty in all the patients who had solitary stones and in three-quarters of those with multiple stones.

 

Any fragments of stone which remain can act as a nidus for recurrent stones, but at the moment the recurrence rate after complete clearance of the gallbladder is not known.

 

Cholecystectomy

Cholecystectomy is the most common major abdominal operation in the Western world, and the rules for its safe execution are well established even though there are a number of different techniques. Elective operations, planned for the convenience of the patient and the surgeon, play an important role in training because a cholecystectomy teaches several important surgical principles. A routine operation requires careful dissection within a confined space in an important anatomical area and no major structure should be divided until the anatomy has been clearly identified. A certain degree of surgical skill is needed and successfully completing the operation is always a landmark in a young surgeon's career.

 

Patients who are admitted as emergencies may require an immediate operation by an experienced surgeon. More commonly they will respond to conservative treatment and should undergo operation on the next convenient list. There are no surgical advantages in waiting for 6 weeks while the inflammation subsides although there may, on occasion, be medical advantages. With the advent of ultrasound it is now easy to make the diagnosis acutely. A delayed operation is no easier and several trials have shown that the early operation is not associated with a greater risk of damage to the bile duct. Furthermore conservative treatment fails for one in seven patients, and a similar number are readmitted with a further acute attack before their planned admission date. From the economic point of view operation during the first admission saves money.

 

Preoperative preparation

Fluid depletion and electrolyte imbalance should be corrected in the acutely ill patient, and blood should be grouped and serum saved for crossmatching should blood transfusion be needed.

 

Routine preoperative antibiotic prophylaxis to prevent wound infection is always appropriate. Although the incidence of anaerobic bacteria in the biliary tract is low our present practice is to give everyone metronidazole 0.5 g and cefuroxime 1.5 g intravenously on induction of anaesthesia. This is probably sufficient, but some surgeons also give a second dose 12 h after operation.

 

Routine prophylaxis against deep venous thrombosis is also necessary. Patients undergoing elective operations should stop the contraceptive pill 1 month in advance and everyone should wear compression stockings on their legs. Patients as well as staff should appreciate the importance of mobility after the operation. Several drugs reduce the incidence of deep vein thrombosis, and some also reduce the incidence of pulmonary embolism. Our choice is to give 500 ml Dextran 70 during surgery and a further 500 ml during the first 24 h postoperatively. High-risk patients receive 6000 units heparin by subcutaneous injection 2 h before operation and every 12 h thereafter.

 

Operative technique

The principles of the operation are the same whichever surgical approach is used. They are to isolate, occlude, and divide the cystic artery and the cystic duct, and then to remove the gallbladder from the liver bed. A peroperative cholangiogram helps to delineate the biliary anatomy and to identify stones in the bile duct: the operation is best performed on an operating table suitably adapted for cholangiography. General anaesthesia with good relaxation provides the best exposure.

 

Open operation

Conventional incision

Four incisions can be used for cholecystectomy: midline, right paramedian, right subcostal, or right transverse. A midline incision is useful when the diagnosis is not definite, while a subcostal incision gives the best exposure when difficulties are expected. However, it does not provide good access to the rest of the abdomen. A transverse incision gives a good cosmetic result and less postoperative pain but provides more limited exposure. Choosing the most appropriate incision for any particular patient depends partly on the preference of the surgeon, partly on the build of the patient, and partly on the expected pathology. Improvements in preoperative diagnosis have reduced the need for a full diagnostic laparotomy. On the other hand it is easy and essential always to examine the gallbladder, the liver, the pancreas, the stomach, and the duodenum. In most operations it will be possible to assess the diameter of the bile duct.

 

⇐ Предыдущая567891011121314Следующая ⇒

Поделиться: