Distraction Stabilization of Degenerative Lumbosacral Stenosis: Technique and Mid- to Long-Term Outcome in 30 Cases

To describe the dorsal laminectomy, annulectomy and distraction stabilization with pins and polymethylmethacrylate technique, its complications and outcome in the management of canine degenerative lumbosacral stenosis. To determine pre- and post-surgical foraminal width and vertebral step changes.

Multi-institutional retrospective clinical study.

Medical records (2005-2020) of dogs treated (n = 30). Clinical signs, Modified Frankel Score, Texas Spinal Cord Injury Score, pain score (dorsal palpation of spine, tail dorsiflexion), imaging findings and complications were retrieved pre-operatively, perioperatively and at long-term follow-up.

The most common presurgical imaging findings were disc protrusion (24/25) and sclerosis of the caudal end-plate of L7 (23/30). On short- to long-term assessment 18 out of 21 dogs exhibited clinical improvement and all exhibited improved pain scores (p < 0.0001). Catastrophic complications occurred in 3 dogs, and major complications occurred in 5, of which 3 required additional surgery. Mean lumbosacral step defect reduced 60% (1.8 mm ± 2.5 mm pre-surgery to 0.7mm ± 0.9mm post-surgery, p = 0.1585). Mean foraminal width significantly increased 50% long-term (3.3 mm ± 1.0 mm pre-surgery to 5.0 mm ± 0.9 mm post-surgery, p < 0.0001).

Dorsal laminectomy, annulectomy and distraction stabilization is a complex procedure which can significantly increase foraminal width, reduce pain and improve gait characteristics in dogs in the short- to long-term, and should be performed by surgeons experienced in lumbosacral pin placement.