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

Abstract

OBJECTIVE: &#x2003;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. STUDY DESIGN: &#x2003;Multi-institutional retrospective clinical study. METHODS: &#x2003;Medical records (2005-2020) of dogs treated (&#x2009;=&#x2009;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. RESULTS: &#x2003;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 (&#x2009;<&#x2009;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&#x2009;mm&#x2009;&#xb1;&#x2009;2.5&#x2009;mm pre-surgery to 0.7mm&#x2009;&#xb1;&#x2009;0.9mm post-surgery,&#x2009;=&#x2009;0.1585). Mean foraminal width significantly increased 50% long-term (3.3&#x2009;mm&#x2009;&#xb1;&#x2009;1.0&#x2009;mm pre-surgery to 5.0&#x2009;mm&#x2009;&#xb1;&#x2009;0.9&#x2009;mm post-surgery,&#x2009;<&#x2009;0.0001). CLINICAL SIGNIFICANCE: &#x2003;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.