Ultrasonic Identification and Laparoscopic Approach of an Abdominal Mass in a Patagonian Sea Lion (Otaria flavescens)
In February 2008, during a routine ultrasound exam, a mass was identified adjacent to the left kidney and ovary in a 7.5 year-old Patagonian sea lion (Otaria flavescens) held at the Parc Zoologique d'Amneville in France. The mass, appearing to be an ovarian tumor, grew rapidly and its structure changed in the subsequent months, reaching a size of 9.6 x 5 cm in May. Because of this drastic change in a short time it was decided to perform an exploratory laparoscopy and possible excision the next month to avoid facing a difficult case during the busy summer period. The animal was anesthetized with a combination of Medetomidine (20 µ/kg) + Zoletil (Zolazepam + Tiletamine) (0.7 mg/kg), intubated and kept under Isoflurane gas anesthesia (0.6-1.5 % maintenance). The laparoscopy allowed a good visualization of the abdominal cavity and identification of the mass. However it was very difficult to confirm if the mass was attached to the left kidney or ovary due to all the connective tissues that had developed between the different organs. Excision of the tumor was started but because of the complexity of those connections and some bradycardia (50 BPM), it was decided to stop, wake the animal, and then discuss further the surgery details and contingency plans. Unfortunately the animal went into cardiac arrest while still under anesthesia. She was resuscitated with intracardiac injections of adrenaline and atropine, but succumbed a couple of minutes later. Although saddened by the circumstance, it was chosen to continue the laparoscopic exploration to gain knowledge and attempt the excision of the mass. The mass was excised from the left ovary, the right kidney was confirmed with an enlarged hiatus (as previously seen on ultrasound) and the lungs were observed through a trans-diaphragmatic approach and had a cottage cheese/omelette like appearance. The necropsy was performed the next morning.