General Anesthesia and Surgery to Treat a Mandibular Sequestrum in an Atlantic Bottlenose Dolphin (Tursiops truncatus)
American Association of Zoo Veterinarians Conference 2017
Lara A. Croft1, DVM; Stacy DiRocco1, DVM; Michelle Davis1, DVM, DACZM; Todd Schmitt2, DVM; James Bailey3, DVM, MS, DACVA; Dean Hendrickson4, DVM, MS, DACVS
1SeaWorld Orlando, Orlando, FL, USA; 2SeaWorld San Diego, San Diego, CA, USA; 3Innovative Veterinary Medicine, Gainesville, FL, USA; 4College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA


An adult male bottlenose dolphin (Tursiops truncatus) presented with diffuse swelling of the frenulum and intermittent swelling along the lateral aspect of the right mandible. This dolphin had sustained an open fracture of right caudal mandible 6 years previously. Radiographs revealed chronic sequestrum formation with free fragments of bone present within a well-demarcated lytic cavity. Treatment of the sequestrum required general anesthesia and surgical debridement of the mandible. The dolphin received 0.27 mg/kg oral diazepam in a single, easily digestible fish 2 hours prior to handling. Additional premedications (0.05 mg/kg midazolam and 0.1 mg/kg butorphanol IM) were administered immediately after removing dolphin from pool. For induction, 5 mg midazolam, then 3 mg/kg propofol were administered slowly through an IV catheter placed in the lateral peduncle. Intubation was accomplished by manual dislocation of the goosebeak and insertion of an 18-mm ET tube. Anesthetic maintenance was with sevoflurane at 1–3%. Surgery was performed with the dolphin in sternal recumbency to allow for optimal ventilation. An incision was made on the lateral aspect of the mandible after review of pertinent vasculature.1 Bone curettes were used to remove any abnormal tissue, then endogenous PRP was infused into the bone defect. Closure was in two layers with overlying silicone button stents to help distribute tension over skin. Flumazenil, naloxone, and then naltrexone were all given intravenously to reverse sedative and respiratory depressant effects of midazolam and butorphanol. The dolphin recovered well from anesthesia and surgery and exhibited decreased swelling and improved comfort (interpreted by cessation in rubbing behavior) following the procedure.


The authors would like to thank the veterinary services and animal care department at SeaWorld Orlando for their dedication and assistance in this dolphin’s care.

Literature Cited

1.  Costidis A, Rommel SA. Vascularization of air sinuses and fat bodies in the head of the bottlenose dolphin (Tursiops truncatus): morphological implications on physiology. Front Physiol. 2012;3:243.


Speaker Information
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Lara A. Croft, DVM
SeaWorld Orlando
Orlando, FL, USA

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