Abstract
Background: pectus excavatum is a rare congenital or developmental deformity of the chest wall that has been reported in both dogs and cats. The clinical symptoms varies in severity and are correlated with the grade of the deformity. The most severe cases are at very high risk of intra- and post-operative complications that could result fatal.
Case description: a 3-months old kitten was presented for severe dyspnea and exercise intolerance. After the radiographic diagnosis of the severe pectus excavatum, a splint was designed based on the CT-scan of the kitten. A locking mechanism was applied on a dedicated pocket on the splint and secured with commercial glue. Five sutures were placed, the most caudal three with a surgical approach to the corresponding sternebra. The three caudal traction sutures were progressively tensioned during the first two weeks, then tied. The splint was removed one month post-operatively, neither surgical nor splint-associated complications were observed. The kitten well tolerated the splint and no further episodes of dyspnea or exercise intolerance were reported by the owner. Vertebral and frontosagittal indexes were 3.2 and 9.1 at presentation, respectively, and 10.2 and 2.0 four months post-operatively.
Conclusion: the use of a patient specific 3D-printed external splint associated with a progressive correction of the pectus excavatum can be a better solution for the treatment of severe cases of pectus excavatum, where a sudden distension of the rib cage could cause re-expansion injuries.

Key words: cat, pectus excavatum, splint, thoracic surgery, 3D printing