Pelvic Endoprosthesis after Hemipelvectomy Using a 3D-Printed Osteotomy Guide for Infiltrative Osteoma in a Cat

With the development of 3D printing and surgical techniques, various defect reconstruction methods after tumor resection have been applied not only in humans but also in veterinary medicine. This report describes a case of reconstruction after hemipelvectomy for an osteoma in a cat using a 3D-printed pelvic endoprosthesis and micro total hip replacement (mTHR). A 5-year-old spayed female Turkish Angora cat was referred for a 1-month history of constipation and intermittent weight-bearing lameness in the left hindlimb. An osteoma in the pelvis measuring 4.5 × 3 × 5.4 cm was identified based on diagnostic examinations. A left mid-to-caudal partial and right caudal partial hemipelvectomy, and a left femoral head and neck osteotomy, were planned to remove the mass. Reconstruction of the bone defect using 3D-printed metal endoprosthesis and mTHR in the left hindlimb was intended. During right caudal partial hemipelvectomy, right femoral head and neck osteotomy was performed because there was infiltration in the medial wall of the acetabulum. Histopathological examination confirmed the diagnosis of an osteoma. Two weeks post-surgery, surgical debridement and femoral stem removal were performed because of delayed wound healing and sciatic neurapraxia, leading to femoral stem dislocation from the cup. The delayed wound healing and sciatic neurapraxia were appropriately addressed. The cat regained normal weight and defecation 4 weeks post-operatively. Two years post-surgery, the patient recovered with an almost normal gait. Hemipelvectomy with 3D-printed endoprosthesis provides a safe surgical option with favorable outcomes for neoplasms in the pelvis of cats.