Pedicle Screw-Rod Fixation of the Canine Lumbosacral Junction

• Published in: Veterinary surgery 2012-08, Vol.41 (6), p.720-732
• Main Authors: Smolders, Lucas A., Voorhout, George, van de Ven, Renée, Bergknut, Niklas, Grinwis, Guy C. M., Hazewinkel, Herman A. W., Meij, Björn P.
• Format: Article
• Language: English
• Subjects: Animals; Bone Screws - veterinary; Bone surgery; Cadaver; Clinical Science; Diskectomy - veterinary; Dog Diseases - surgery; Dogs; Klinisk vetenskap; Laminectomy - veterinary; Lumbosacral Region - surgery; Pilot Projects; Spinal Cord Compression - surgery; Spinal Cord Compression - veterinary; Spinal Fusion - instrumentation; Spinal Fusion - methods; Spinal Fusion - veterinary; Spine; Surgical outcomes; Transplants & implants; Veterinary medicine
• ISSN: 0161-3499; 1532-950X; 1532-950X
• DOI: 10.1111/j.1532-950X.2012.00989.x

Objective To assess pedicle screw‐rod fixation (PSRF) of the canine lumbosacral junction (LSJ) ex vivo and in vivo. Study Design Ex vivo cadaver study and in vivo pilot study. Sample Population Six canine cadaveric lumbosacral spinal specimens and 3 Greyhound dogs diagnosed with degenerative lumbosacral stenosis (DLSS). Methods Ex vivo study: PSRF of the LSJ was performed in 6 spinal specimens using guidelines and was evaluated by radiography, computed tomography, and magnetic resonance imaging. In vivo study: 3 Greyhounds diagnosed with DLSS had dorsal laminectomy and partial discectomy combined with PSRF of the LSJ. Curettage of the endplates with insertion of an autologous cancellous bone graft was performed to promote spinal fusion. During 18‐month follow‐up, dogs were monitored by clinical evaluation, diagnostic imaging, and force plate analysis. Dogs were euthanatized for reasons unrelated to PSRF or their lumbosacral disease, and postmortem imaging and histopathologic investigations of the LSJ were performed. Results Ex vivo study: Sixteen of 24 inserted screws had an acceptable placement. In vivo study: Ten of 12 inserted screws had acceptable placement. Clinical signs of ``lower'' back pain resolved at 4 weeks after surgery. Diagnostic imaging and histopathology showed no bony spinal fusion of the LSJ. Force plate analysis revealed a trend toward improved pelvic limb function relative to preoperative function. Conclusions PSRF of the LSJ of large breed dogs is technically possible. Improvements to the surgical technique to induce spinal fusion and assessment in a larger sample size are required before it can be recommended.