# Lumbar and lumbosacral spondylosis deformans in a crab-eating fox (Cerdocyon thous): a longitudinal radiographic case

## TL;DR

A crab-eating fox developed chronic spinal degeneration, and radiographic monitoring showed worsening over five years.

## Contribution

This is the first longitudinal radiographic case report of spondylosis deformans in a crab-eating fox.

## Key findings

- Initial radiographs showed ventral osteophyte formation and disc space narrowing in the lumbar and lumbosacral spine.
- Follow-up radiographs revealed progression of degenerative changes, including increased bony proliferation and disc space reduction.
- Serial radiography proved effective for monitoring chronic vertebral degeneration in wild canids under human care.

## Abstract

Spondylosis deformans is a chronic degenerative disorder of the vertebral column that has been extensively described in domestic dogs but remains poorly documented in wild canids. The crab-eating fox (Cerdocyon thous) is frequently admitted to wildlife rehabilitation centers, and the characterization of musculoskeletal disorders in this species is particularly relevant given its ecological plasticity and close association with anthropized environments. This report describes a case of spondylosis deformans affecting the lumbar and lumbosacral spine of an adult neutered male Cerdocyon thous maintained under human care, which presented self-mutilation behavior and clinical signs consistent with lumbosacral pain. Three radiographic examinations of the vertebral column were performed in October 2021, October 2024 and January 2026, allowing longitudinal assessment of the lesion progression and stabilization patterns. The initial examination revealed ventral osteophyte formation, narrowing of intervertebral disc spaces, and vertebral endplate sclerosis involving the caudal lumbar vertebrae and the lumbosacral segment. At the follow-up examination, progression of the degenerative changes was evident, characterized by extensive ventral bony proliferation, greater involvement of the lumbosacral region, and further reduction of intervertebral disc spaces. Longitudinal comparison demonstrated a marked increase in both the extent and severity of the lesions over a five-year follow-up period, consistent with the chronic progression of spondylosis deformans. Serial radiography proved to be a valuable tool for the recognition and monitoring of degenerative vertebral disorders and may support clinical management of wild canids under human care.