TECHNIQUE

Cholecystectomy in Bears (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords Gall bladder removal
Description This procedure is described for the treatment of bears which have been on bear bile farms and have had surgery for the collection of bile by a surgically implanted catheter or "free-dripping" fistula. This description has been provided by Animals Asia Foundation veterinarians, based on their extensive experience with this operation in bears rescued from bear bile farms.

NOTE: Although the procedure is described below as accurately as possible, this is NOT a substitute for learning the procedure by watching and assisting a veterinarian who is already experienced in the technique.

Anaesthesia, analgesia and maintenance

[Editor's note: the following anaesthesia and analgesia regime is the one followed at Animals Asia Foundation, where this operation has been carried out on hundreds of bears.]

  • Anaesthetise the bear using an initial dose (for non-stressed bears) 1 mg/kg Zoletil (tiletamine-zolazepam) plus 0.01 mg/kg medetomidine (reconstitute Zoletil-100 with 5 mL medetomidine 1 mg/mL to give 100 mg/mL tiletamine/zolazepam and 1 mg/mL medetomidine).
    • With stress or disturbance the dose needs to be increased.
    • If necessary, given an additional dose, based on the bear's state of sedation, to a maximum of 3 mL/100 kg of the medetomidine/tiletamine/zolazepam mixture.
    • Do not remove the bear from its cage until the palpebral reflexes and tongue withdrawal reflexes are absent.
  • Maintain on isoflurane at a flow rate of 1-2% (or higher if required). Halothane has been used also.
  • Give carprofen, 3.2 mg/kg subcutaneously as soon as the bear has been anaesthetised.
  • Give enrofloxacin, 5.0 mg/kg subcutaneously before starting the operation.
  • Give butorphanol, 0.075 mg/kg intramuscularly into the pectoral muscles 20 minutes before the onset of surgery then hourly during surgery. Or give morphine, 0.1 - 0.5 mg/kg intramuscularly or intravenously every 2-4 hours.
    • An apparent excitatory response to morphine has been seen in one bear.
  • Place an intravenous catheter into a cephalic or saphenous vein.
  • During anaesthesia, give warmed lactated Ringer's solution at a rate to maintain PCV. PCV and urine specific gravity are measured every hour; PCV is generally between 40% and 50%. Roughly, a 3 or 4 hour surgery requires about 4 liters of fluids in an average (100 to 150 kg) bear.
  • In cold ambient temperatures, keep the bear warm, e.g. with an electric heater beneath the operating table and hot water bottles along the bear's flanks (also useful for maintaining the bear's position).
  • In warm ambient temperatures, place cold water bottles along the bear's flanks (also useful for maintaining the bear's position).
  • Clip and shave the bear's abdomen around the surgical site.
  • Monitor and record the bear's rectal temperature every 30 minutes during surgery.
  • Monitor and record the bear's heart rate, respiratory rate, pCO2 and oxygen saturation every five minutes.
  • Monitor and record the bear's blood pressure every 10 minutes.
  • Further information on anaesthesia and monitoring are provided in Treatment and Care - Anaesthesia
Surgery
  • Make an elliptical incision in the skin around the bile duct fistula. 
    • The length and width of the incision is determined from the size of the mass palpated beneath the fistula and visualised ultrasonographically.
    • There is often a large mass of fibrotic tissue and old abscesses surrounding the gall bladder.
    • If there is an associated hernia, the incision must be sufficiently large to allow repair of the hernia,
  • Bluntly dissect through the subcutaneous tissues to the abdominal muscles.
    • Depending on the degree of inflammation and infection, the tissues may be extremely vascular.
    • Control bleeding with radio cautery and by ligation of vessels.
    • Note there are often abscesses in the subcutaneous tissues, commonly associated with old suture material.
  • Enter the peritoneal cavity at a point caudal to the fistula.
    • Note that in bears with a fistula the gall bladder is just below the abdominal surface, attached to the fistula.
    • Take care to avoid both the gall bladder and its surrounding mass of tissue while entering the abdominal cavity.
  • Make the opening large enough for the surgeon to insert a hand into the abdomen and locate the gall bladder manually.
  • Once the position of the gall bladder is determined, carefully transect the abdominal muscles around the gall bladder.
    • Constantly refer to the underlying mass of the gall bladder and associated tissues.
    • An assistant holds the fistula and its surrounding island of skin and muscle using an Allis tissue forcep.
  • NOTE: At the cranial end of the incision, which often abuts the rib cage, usually off-centre, take care to identify and avoid the large blood vessels in this area.
  • Once the gall bladder and associated mass are isolated in the centre of the aperture, dissect away the mesentery, omentum and other connecting tissues away from the mass, deep into the abdominal cavity, to several centimetres along the cystic duct.
    • Carefully examine the gall bladder, particularly at the fundus end where it is attached to the fistula, for areas of weakness or potential leakage.
    • At the cranial end of the incision it is common to find that the mass of tissue or an abscess has grown into a liver lobe and needs to be trimmed away.
    • The normal band of tissue connecting the small accessory lobe of the liver to the gall bladder needs to be transected.
    • Note: the tissues surrounding the gall bladder are very vascular. Careful dissection is required, with ligation of the numerous blood vessels.
  • Once the gall bladder and as much as possible of the cystic duct have been freed, place two bowel clamps across the cystic duct, as deep as possible, and proximal to another clamp which will be removed with the gall bladder.
  • Place two Allis tissue forceps on either side of the cystic duct, proximal to the most proximal of the bowel clamps, to provide additional security to the stump of the duct until it is ready to be released.
  • Have the surgical assistant hold the Allis forceps.
  • Transect the cystic duct between the two distal clamps (leaving the two bowel clamps attached to the stump) and the distal section with the gall bladder, and remove the gall bladder and distal duct.
  • If gall stones or "sand" has been palpated inside the gall bladder and duct, flush the duct by inserting a 16-gauge intravenous catheter into the open end of the cystic duct, carefully loosening one bowel clamp at a time to let the catheter through, and flush 20-60 mL of sterile saline through the remaining cystic duct into the duodenum.
  • Ligate the blood vessels running along either side of the cystic duct with 3-0 Vicryl.
  • Suture the open end of the cut stump in two layers, using 3-0 Vicryl, in first a horizontal then a vertical inverting suture pattern.
  • Once the surgeon is satisfied with the closure of the stump, release the duct.
  • Make a tactile exploration of the abdominal cavity to locate any foreign objects, abscesses or organ abnormalities.
  • Flush the abdominal cavity with one litre of warm sterile saline.
  • Infuse 1 000 000 IU Penicillin G, suspended in 5 mL of sterile water, into the abdominal cavity.
  • Close the abdominal cavity in three layers:
    • Close the muscle layer with a cruciate pattern using 0-0 or 1-0 PDS, placing the sutures at least 3 cm from the margin of the incision. Oversew with a simple continuous suture of the same material.
    • Close the subcutaneous layer with 0-0 or 2-0 Vicryl (depending on the quality and thickness of the tissue, in a simple interrupted or continuous pattern, taking care to close the dead space between the subcutaneous tissue and the muscle. 
      • Prior to closing this layer, it may be flushed with dilute (5%) metronidazole. 
    • Use 2-0 Vicryl for the subcuticular suture.
Reversal of anaesthesia
  • With the bear back in its cage, give atipamezole intravenously into the jugular vein: 1 mL for each mL medetomidine given within the last hour, plus 0.5 mL for every 1 mL medetomidine given more than one hour previously. 
Post-operative care
  • For analgesia, carprofen, 1.8 mg/kg orally once daily for 3-4 days (the dose may be increased to 1.8 mg/kg twice daily if the surgery has been particularly traumatic).
  • Antibiotics: enrofloxacin, 5.0 mg/kg orally once daily for at least 10 days (tablets can be crushed and given to the bear in a fruit shake).
    • Note: bears from Chinese bile farms may have been given a wide variety of antibiotics and infections may therefore be resistant to many of the commonly-available antibiotics.
    • Alternatively, amoxycillin/clavulanic acid may be given.
    • Note: Culture and sensitivity assays are not generally available for choosing antibiotics.

(V.w89, V.w90)

Appropriate Use (?)
  • For bears which have had gall bladder implants or "free dripping" fistulas created. See: Gall Bladder Fistula in Bears
  • Note: all bears which have had implants or fistulas, including those in which the fistula has closed, have significant gall bladder pathology.
  • It is necessary to carry out a complete cholecystectomy. All bears which have been fistulated (with or without an implanted catheter) have significant gall bladder pathology. Experience has shown that if only the damaged area of the gall bladder fundus is removed, further complications develop and cholecystectomy is required later.
  • Euthanasia is appropriate if inoperable tumours are detected at the time of surgery.
Notes
  • Surgery takes 3 to 6 hours on average. (V.w89)
  • Removal of several centimetres of cystic duct is recommended to prevent subsequent formation of gall stones in the distal end of the cystic duct.
Complications/ Limitations / Risk
  • Bile is caustic to tissues and precipitates severe inflammation if it leaks into the abdominal cavity. (P3.2006b.w1) Care must be taken not to puncture the gall bladder during surgery. 
Equipment / Chemicals required and Suppliers
  • Surgical kit including bowel clamps, Allis forceps and appropriate suture materials.

  • Appropriate anaesthetic, analgesic and antibiotic agents for use during the procedure and for post-operative care.

Expertise level / Ease of Use
  • This procedure should be carried out only by a competent veterinary surgeon who has been trained in the technique by a veterinarian who is already experienced with this operation.
Cost/ Availability
  • The costs of this procedure include the costs of the personnel required (minimum one veterinary surgeon to carry out the operation, one surgical assistant and one person to monitor the anaesthetic)
Legal and Ethical Considerations
  • In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery." (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons).).
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Suzanne I. Boardman BVMS MRCVS (V.w6), Gail Cochrane BVMS MRCVS (V.w89), Kati Loeffler DVM PhD (V.w90)
References V.w89, V.w90

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