Abstract
Introduction: Current evidence suggests that CES should be operated within 48 hours from onset of sphincteric symptoms in order to maximise chances of recovery. Measurement reproducibility of large disc prolapses and clinical correlations have not previously been studied.
Objectives: (1) Determine whether initial MRI findings correlate with clinical outcome (2) Study the reproducibility of MRI measurements of large disc prolapses (3) Estimate the ability to predict CES based on MRI alone.
Study Design: 31 patients with CES were identified, the case notes reviewed and the patients invited to attend clinic. Outcome consisted of history and examination, and several validated questionnaire assessments. 19 patients who underwent discectomy for persistent radiculopathy were identified. None had sphincteric symptoms. All had a significant surgical target. Digital photographs of all 50 MRIs were obtained showing the T2 mid-sagittal image and the axial image with the greatest disc protrusion. The Observers: 1 Consultant Radiologist, 2 Consultant Spinal Surgeons and 1 SHO did not know the number of patients in each group. Observers estimated the percentage spinal canal compromise on each view and indicated whether they thought the scan findings could produce CES. Measurements were repeated after 2 weeks.
Results: 26 patients attended clinic mean follow up 51 months (25 to 97). As expected, the % canal compromise differed significantly between the two groups (p0.001). 12 of the 26 patients with CES had, on average, over75% canal compromise. No significant correlations were found between MRI canal compromise and clinical outcome. Canal compromise did predict whether the patient would fail their Trial Without Catheter (p0.05). Based on MRI alone, the correct identification of CES has sensitivity 68%, specificity 78%, positive predictive value 84% and negative predictive value 58%. Kappa values for intra-observer reproducibility ranged from 0.4 to 0.85 for sagittal compromise, axial compromise and correct prediction of CES. All three interobserver kappa values for these measurements were 0.64.
Conclusions: This is the largest radiological case series of CES with 4 years clinical follow up. Canal compromise on MRI does not appear to directly predict clinical outcome. Reproducibility of MRI measurements of large disc protrusions has substantial agreement. MRI could be of help in equivocal cases if the scan shows a large disc.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
