Evaluation of the intervertebral disk, vertebral body, and spinal cord for changes secondary to percutaneous laser disk ablation.

Abstract

OBJECTIVE: To evaluate the intervertebral disk, vertebral endplates, and spinal cord for perioperative changes secondary to percutaneous laser disk ablation (PLDA) and correlate findings to clinical outcomes in dogs receiving thoracolumbar PLDA. STUDY DESIGN: Blinded study. ANIMALS: Thirty dogs. METHODS: Magnetic resonance imaging (MRI) was performed before PLDA (control/Group&#x2009;C), immediately following PLDA (Group&#x2009;I), and 3&#x2009;months later (perioperative/Group&#xa0;P). Dogs were followed 3&#x2009;years. Groups and dogs were randomized for evaluation. Two radiologists were blinded to each MRI study and dog. Each radiologist evaluated the disk, vertebral body, and spinal cord at each disk space receiving PLDA. RESULTS: Mean disk degeneration was increased in Group&#xa0;P at L1-2 (p&#x2009;<&#x2009;.0001) and L2-3 (p&#xa0;=&#xa0;.0081). Both radiologists identified mild diskitis (1%-15%) in Group&#xa0;P (radiologist&#x2009;1, p&#x2009;<&#x2009;.0001; radiologist&#x2009;2, p&#xa0;=&#xa0;.0012). Cranial endplate lesions were identified in Group&#xa0;P at T11-12 (p&#xa0;=&#xa0;.0353), T13-L1 (p&#xa0;=&#xa0;.0026), and L4-5 (p&#xa0;=&#xa0;.0210). Lesions were identified in the caudal endplates of all eight disk spaces in Group&#xa0;P: T10-11 (p&#xa0;=&#xa0;.0004), T11-12 (p&#x2009;<&#x2009;.0001), T12-13 (p&#x2009;<&#x2009;.0001), T13-L1 (p&#x2009;<&#x2009;.0001), L1-2 (p&#x2009;<&#x2009;.0001), L2-3 (p&#x2009;<&#x2009;.0001), L3-4 (p&#x2009;<&#x2009;.0001), and L4-5 (p&#x2009;<&#x2009;.0001). There was no disk extrusion or spinal cord lesions identified. CONCLUSION: This study evaluated effects that may occur secondary to PLDA, using MRI. Although vertebral body changes were identified, they did not correlate with clinical complications. CLINICAL SIGNIFICANCE: PLDA appears to be a safe, effective procedure performed on thoracolumbar disks to reduce recurrence of intervertebral disk herniation (IVDH) in dogs that previously experienced IVDH, despite the appearance of visible vertebral endplate lesions and mild diskitis on MRI.