Abstract
Background:
Working dogs routinely engage in demanding physical activities, such as sprinting, jumping, apprehension tasks, and vertical searches, which exert substantial biomechanical stress on the lumbosacral (LS) spine. This repetitive stress predisposes them to degenerative lumbosacral stenosis (DLSS) and cauda equina syndrome, common conditions that can limit their active service life. Osteochondritis dissecans (OCD) of the sacrum is an uncommon, likely underrecognized cause of cauda equina syndrome in dogs, resulting from abnormal endochondral ossification and potentially causing nerve root compression. Although conservative treatments, surgical interventions, and epidural corticosteroid infiltrations have been utilized for managing general lumbosacral pathologies, specific reports detailing epidural corticosteroid therapy for sacral OCD in working dogs remain limited.

Case Description:
A 6-year-old, 38 kg, intact male Dutch Shepherd working dog presented with persistent intermittent left pelvic limb lameness initially attributed to a suspected cranial cruciate ligament injury. Advanced diagnostic imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), identified a sacral OCD lesion contributing to DLSS and cauda equina syndrome and associated left sciatic nerve root inflammation. Conservative management with a three-part series of methylprednisolone acetate epidural steroid infiltrations (ESIs) at time points day 0, 2 weeks, and 6 weeks post initial treatment, resulted in significant clinical improvement, allowing the dog to return to full active duty for detection and apprehension. The working dog required a repeated series of ESIs approximately 18 months later due to recurrence of mild clinical signs, again responding positively, and has remained in active duty and fit for deployment.

Conclusion:
This report describes the first documented case of a sacral OCD lesion associated with cauda equina syndrome successfully managed with a series of ESIs in a working dog, facilitating sustained return to high-level active duty and deployment. This minimally invasive management strategy warrants consideration in similarly affected dogs, particularly working dogs, to provide effective, targeted anti-inflammatory therapy for sacral OCD-associated cauda equina syndrome where maintenance of active duty and minimal downtime is critical.

Key words: Cauda equina syndrome; Degenerative lumbosacral stenosis; Epidural steroid infiltration; Sacral OCD; Working dog.