Patient-specific three-dimensional-printed models for canine adrenalectomy: a report of three cases

<b>Case history:</b> Three dogs with adrenal masses scheduled for adrenalectomy were prospectively enrolled into a study to investigate the effectiveness of a 1:1-scale, three-dimensional (3D) printed model of neoplastic adrenal glands to aid surgical planning and provide intra-operative assistance during adrenalectomy in dogs.Case 1 presented with anorexia, lethargy and a distended abdomen; Case 2 with loss of appetite, behavioural changes, and vocalisation; and Case 3 with mild inappetence during the previous 15 days.<b>Clinical and imaging findings:</b> On physical examination, mild abdominal pain was noted in all cases. Case 1 was consistently mildly hypertensive over repeated measurements. All cases had mild or moderate elevations in the activities of alanine aminotransferase and aspartate aminotransferase, and the concentration of C-reactive protein. Cases 1 and 2 also had mild leucocytosis. Abdominal CT revealed a left-sided adrenal tumour with caval invasion in Case 1, and right-sided adrenal tumours without caval invasion in Cases 2 and 3. 3D-printed models were created from the CT scan. Different colours were assigned to anatomical structures for better visualisation. Measurements of six anatomical landmarks were made on CT images and on the 3D-printed model. The median absolute difference in measurements taken from the model and the CT scan was 0.75 (min 0, max 3.2) mm.<b>Treatment and outcome:</b> All dogs underwent surgical removal of the adrenal tumour via sterno-pubic celiotomy. Placing the 3D model on the operating table in the same orientation as the patient allowed for precise pre-planning of the dissection depth. Printed without the fat, and fibrous and capsular tissues that typically cover the retroperitoneal space, the model helped the surgeon to visualise vascular structures that were still covered by connective tissue in the patient. Subjectively, the use of 3D models improved surgical planning and execution by enhancing the understanding of anatomical relationships and enabling the accurate identification of surgical landmarks.No major intra-operative complications were reported. Post-operative outcomes were favourable, with no significant complications observed.<b>Clinical relevance:</b> The use of 3D-printed models in adrenal surgeries for dogs may enhance the surgeon's spatial awareness and intra-operative confidence. We recommend that these models are used in conjunction with CT imaging for effective pre-operative planning. Further research with larger sample sizes and a control group would allow a fuller exploration of the benefits of 3D-printed models in veterinary surgical practices.<b>Abbreviations:</b> ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; CRP: C-reactive protein; CVC: Caudal vena cava; 3D: Three-dimensional.