There are a number of minimally invasive surgical (MIS) procedures that are currently performed using laparoscopy. Many of these procedures require multiple trocar cannula portals, specific minimally invasive surgical instruments, loop ligatures, clip applicators and monopolar electrosurgery. The techniques described below are the 'tip of the iceberg' in as far as the potential for MIS in veterinary medicine.
Laparoscopy
Intestinal Biopsy
Small intestinal biopsies can be obtained using the laparoscope simply by exteriorizing a piece of intestine through the abdominal wall and then collecting the sample externally as would be done with a standard surgical biopsy. A 5 mm atraumatic grasping forceps with multiple teeth is used to grasp the intestine at the site to be biopsied. It may be necessary to 'run' the bowel with two grasping forceps to select a location to biopsy. The antimesenteric border is firmly grasped with the forceps. The intestine is then pulled to the cannula. A 3-4 cm loop of intestine is exteriorized. A small full thickness biopsy is then obtained in the same manner as one would use when performing an open abdominal surgical technique. The intestine is then returned to the abdominal cavity. If too much intestine is exteriorized it is difficult to return it to the abdominal cavity through a small incision.
Intestinal Feeding Tube Placement
Duodenostomy or jejunostomy feeding tubes can be placed using the laparoscope simply by exteriorizing a respective piece of intestine through the abdominal wall and inserting the tube externally. Once the location of the bowel for tube placement is determined, the antimesenteric border is firmly grasped with the forceps. The intestine is then pulled close to the cannula in which the intestine will be exteriorized. A 3-4 cm loop of intestine is exteriorized and four stay sutures (4-0 monofilament absorbable) are placed in the intestine to prevent the intestine from falling back into the abdominal cavity. A purse-string suture is placed on the antimesenteric border of the intestine. A number 11 blade is used to puncture the intestine in the middle of the purse-string suture and the jejunostomy feeding tube (5 French for cats and 8 French for dogs) is introduced in the loop of bowel in the aboral direction. The purse string suture is closed and the intestine is returned to the abdominal cavity except for the segment containing the feeding tube. The stay sutures are then used to pexy the intestine to the abdominal wall using 4.0 monofilament absorbable sutures. The abdominal wall is then closed with simple continuous suture pattern. Subcutaneous tissue and skin are closed in a routine fashion. The feeding tube exits through the incision.
Gastropexy
A preventive gastropexy can be performed using the laparoscope simply by exteriorizing the pyloric antrum region of the stomach through the right abdominal wall.The animal is placed in dorsal recumbency and the telescope portal is placed on the midline at the level of the umbilicus. A 5 mm atraumatic grasping forceps with multiple teeth is used to grasp the pyloric antrum mid-distance between the lesser and the greater curvature. The pyloric antrum is exteriorized after extension of the cannula site situated behind the last rib on the right side. An incisional gastropexy is then performed.
Ovariohysterectomy /Ovariectomy
Ovariohysterectomy or ovariectomy can be performed using laparoscopy in most all medium and large size dogs. The space in the abdominal cavity of small dogs and cats make the procedure technically very difficult. The advantage of this technique is the perceived rapid patient recovery following the procedure.
The procedure is performed in dorsal recumbency approach and the table is tilted at 15 degrees with the head of the dog in a dependent position.
Following insufflation of the abdominal cavity using a Veress needle and CO2, the cannula for the telescope is introduced cranial to the umbilicus. Instrument ports are then placed at the level of the umbilicus on the edge of the rectus abdominalis muscle. In the caudal abdomen, the uterus laying over the colon is visible. After moving loops of intestine and omentum that are covering the ovarian pedicle, one uterine horn is grabbed with a fine tooth grasper and pulled caudally to expose the ovarian pedicle. Electrocauterization is used to cauterize the suspensory ligament while cutting with the scissors. A hole is then made in the mesovarium isolating the ovarian pedicle. The ovarian pedicle can be ligated with either suture, vascular clips, or electrocautery. After placing two sutures or two vascular clips on the ovarian pedicle it is then transected with Metzenbaum scissors. The second ovarian pedicle is then dissected and ligated in a similar fashion.
If only an ovariectomy is performed, another ligature will be placed on each uterine horn before transecting the ovaries from the uterus. Both ovaries will be removed through one cannula site.
If an ovariohysterectomy is being performed, a pre-tied loop of suture (Endoloop SutureTM or Loop LigatureTM) is placed in the abdominal cavity through one of the cannulae. Both ovaries and uterine horns are then passed through the loop. The loop is then tightened down at the level of the cervix. Metzenbaum scissors are used to transect the cervix cranial to the suture. Both ovarian pedicles and the cervix are inspected for bleeding. The uterus and both ovaries are removed through one of the cannula holes which must have been enlarged to receive these organs. The enlarged cannula site is sutured with a simple continuous suture pattern with 2-0 monofilament absorbable suture material. Subcutaneous tissue and skin are closed in a routine fashion. The other cannula sites require only subcutaneous and skin sutures.
Cryptorchid Surgery
A testicle that is located in the abdominal cavity can be removed easily with laparoscopy.Laparoscopic vasectomy can also be performed through this technique.The dog is placed in dorsal recumbency with the table tilted at 15 degrees with the head of the patient in the lower position. Gravity will then displace the abdominal organs in the cranial abdomen, which will facilitate visualization of the internal inguinal canal. The monitor is placed at the end of the table as described for ovariohysterectomy surgery.
The ectopic testicle is usually readily visible upon entering the abdominal cavity. The ectopic testicle of one side rarely ever crosses the midline but stays lateral to the bladder on the affected side. The testicle is grabbed with a fine tooth grasper. The gubernaculum is divided with Metzenbaum scissors and, if needed, electrocautery. The vascular pedicle and the vas deferens are ligated with a pre-tied suture or clips. The ectopic testicle is removed through one the cannula holes that generally must be enlarged. The enlarged cannula site is sutured with a simple continuous suture pattern with 2-0 monofilament absorbable suture material. Subcutaneous tissue and skin are closed in a routine fashion. The other cannula sites require only subcutaneous and skin sutures.
Laparoscopic Cystoscopy
Laparoscopic cystoscopy is an alternative method that allows placement of a laparoscopic telescope into the urinary bladder that has been exteriorized through the abdominal wall for examination, biopsy and calculi removal. The technique involves a standard laparoscopic entry with the telescope placement on the abdominal midline cranial to the umbilicus. Once the urinary bladder is visualized, a second trocar cannula is placed directly over the urinary bladder at the location of exteriorization. Using atraumatic forceps with multiple teeth, the bladder is grasped and pulled into the trocar cannula as described in the intestinal biopsy section. Once the apex of the bladder is exteriorized, stay sutures are placed from the bladder wall. The bladder is temporally pexied to the abdominal wall. A small incision is made in the bladder wall, the bladder is then flushed with sterile saline and the telescope is introduced into the bladder. Forceps can be placed in the lumen along the telescope to obtain a biopsy or remove calculi. At the conclusion of the procedure, the bladder is closed in a standard manner and placed back into the abdomen. The cannula ports are then closed. The pexy is released and the abdominal closed in a routine fashion.
Conclusion
Laparoscopy is a minimally invasive technique for diagnostic and surgical procedures. Once the basic technique of laparoscopy is mastered and the appropriate indications are applied to the procedures it becomes a simple and rewarding addition to small animal veterinary medicine and surgery. As our ability advances, newer diagnostic and therapeutic procedures will no doubt be developed.