EXPRESS: Use of a 3D-Printed Spine Model for Surgical Planning in a Feline Vertebral Chondroblastic Osteosarcoma: A Case Report

A 2-year-old male neutered domestic shorthair cat presented with a 1-month history of nonspecific pain and inappetence, left-sided Horner syndrome, pelvic limb proprioceptive ataxia, upper motor neuron paraparesis, and a plantigrade stance. Advanced imaging revealed a heterogeneous contrast-enhancing extradural mass dorsal to the T1-T2 intervertebral disc space, causing severe left-sided spinal cord compression. Medical image processing software was used to generate a patient-specific 3D spine model based on magnetic resonance and computed tomography data. A biomechanical 3D-printed replica of the T1–T3 region allowed preoperative simulation of a left-sided hemilaminectomy and mass removal, confirming contiguity of the lesion with the T1 vertebral body and extension along the vertebral canal to T2–T3. The model aided intraoperative landmark identification and facilitated safe and effective spinal cord decompression. Histopathology from surgical biopsy was most consistent with either chondroblastic osteosarcoma or chondrosarcoma. Postoperative radiation therapy was initiated but discontinued due to difficulties establishing reliable intravenous access. Progressive neurologic deterioration eventually led to euthanasia. Post-mortem CT and necropsy confirmed a diagnosis of chondroblastic osteosarcoma without evidence of metastatic disease. Survival time of 356 days following surgery (387 days from initial presentation). Relevance and novel information This report describes the first known vertebral chondroblastic osteosarcoma in a cat. It highlights the value of biomechanical 3D-printed spine models for preoperative planning in complex vertebral surgery and demonstrates that tumor debulking, even when combined with incomplete radiotherapy, can provide meaningful palliation and prolonged survival. Further studies are needed to define optimal treatment strategies and prognosis for feline vertebral osteosarcoma subtypes.