Case Report: Extraforaminal endoscopic lumbar discectomy in two dogs with far-lateral intervertebral disc extrusions

Far-lateral intervertebral disc extrusions (IVDE) represent an uncommon subset of intervertebral disc disease in dogs, in which disc material is herniated dorsolaterally or laterally to compress the exiting nerve root in an extraforaminal location. While minimally invasive spinal surgery techniques have been described in dogs, to the authors knowledge, full-endoscopic discectomy has not previously been reported for extraforaminal IVDE. This case report describes the clinical presentation, surgical technique, and short-term outcomes of extraforaminal endoscopic lumbar discectomy (EELD) in two dogs. Two middle-aged crossbreed dogs were presented with subacute onset of vocalization, pelvic limb lameness presumed to be a nerve root signature, and marked lumbar hyperaesthesia without other abnormalities on neurological examination. MRI or CT confirmed L5-6 extraforaminal disc extrusion with L5 spinal nerve root compression in both cases. Medical management failed to resolve clinical signs. Using a uniportal approach, a 6.3 mm diameter working-channel endoscope was fluoroscopically docked onto the transverse process of the vertebra caudal to the affected disc, creating a muscle-sparing lateral corridor. Extruded disc material was visualized, released from its fibrous capsule, and removed piecemeal without the need for osteotomy. Surgical times were 25 and 30 min. Post-operative CT confirmed effective decompression in both dogs. Post-operative recovery was rapid, with low pain scores and no requirement for opioid analgesia. Dogs were discharged within 24 h, and by 3 weeks both were free of lameness and spinal pain. At 12 weeks, caregiver-reported outcomes demonstrated sustained improvement, including a substantial reduction in Canine Brief Pain Inventory scores. EELD provided effective decompression through a minimally invasive corridor with excellent early outcomes. This first description in dogs supports further investigation of EELD as an alternative to conventional open surgical approaches for extraforaminal IVDE.