Minimally Invasive Surgery
World Small Animal Veterinary Association World Congress Proceedings, 2008
Eric Monnet, DVM, PhD, FAHA, DACVS, ECVS
Colorado State University
Fort Collins, CO, USA

There are a number of minimally invasive surgical (MIS) procedures that are currently performed using laparoscopy and thoracoscopy. 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.


Techniques for the following procedures are described fully in a separate presentation on laparoscopy.

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.

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.

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. The feeding tube exits through the incision.


A preventive gastropexy can be performed using the laparoscope simply by exteriorizing the pyloric antrum region of the stomach through the right abdominal wall.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.

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.

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.


Thoracoscopy can be performed with a trans-diaphragmatic or an intercostal approach. The trans-diaphragmatic approach allows visualization of both hemi-thoraces. A long axis view of the thorax is then obtained. This is the approach of choice for exploration of the thoracic cavity and biopsy.


Biopsy of a solid mass in the parietal pleura, lymph nodes, pericardium or right atrium can be collected with a biopsy forceps. Lymph nodes can be completely dissected out with scissors and grasping forceps. Cultures can also be taken. Needle aspiration of lymph nodes can be also guided under thoracoscopy.

Biopsy of the lung requires a pre-tied ligature (EndoLoop) that eliminates knot tying in the thoracic cavity. The EndoLoop is introduced in the thoracic cavity through a cannula. A grasping forceps passed in the loop grasps the tip of the lung to biopsy. The lung parenchyma is pulled back into the loop. The loop is then tied. Metzenbaum scissors are then used to cut the biopsy. Hook scissors are then introduced in the thoracic cavity to cut the ends of the suture.

Pericardial Window

Creation of a window in the pericardium establishes permanent drainage for patients with pericardial effusion. This technique is performed effectively with minimally invasive technique, with greatly reduced operative trauma and postoperative pain. Indications for permanent pericardial drainage include neoplastic effusions, hemorrhage from neoplastic masses, inflammatory disease and idiopathic effusions. This procedure prevents cardiac tamponade in the future by allowing drainage of pericardial fluid into the pleural space. Results with this procedure are excellent with long-term resolution in cases with idiopathic or inflammatory disease, and dramatic improvements in quality of remaining life in neoplasia cases.

Partial Lung Lobectomy

Lung biopsy for chronic lung disease, excision of lung masses, lung abscesses, emphysematous bullae, or any other localized disease process in the peripheral portions of the lung lobes, can be performed quickly and effectively with minimally invasive technique. Partial lung lobectomy can also be performed for diagnostic biopsy of generalized lung disease.

Lung Lobectomy

Complete lung lobectomy can also be performed with minimally invasive technique. Lung lobes with small masses and away from the hilus of the lung can be removed with minimally invasive surgery. Large masses impair visualization of the hilus of the lung and make manipulation of the lung difficult.

Correction of Persistent Aortic Arches

Minimally invasive transection of the ligamentum arteriosum in cases with persistent right aortic arch has been shown to be an effective alternative to the open surgical approach.

The most important benefit from thoracoscopy in small animal surgery is the fast recovery. Since there is no rib retraction during thoracoscopy, and limited incision even to exteriorize a mass, the amount of post operative pain is significantly reduced when compared to thoracotomy.

Speaker Information
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Eric Monnet, DVM, PhD, FAHA, DACVS, ECVS
Colorado State University
Fort Collins, Colorado, USA

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