Utilización de la discografía para el diagnóstico del dolor discogénico: Comparación con la resonancia magnética nuclear

摘要

Objectives: Diskography is an invasive diagnostic procedure performed under fluoroscopic control in order to introduce contrast medium in the nucleus pulposus through puncture of an intervertebral disk. This technique allows disk assessment in terms of manometric and volumetric capacity, radiological image and response to the pain-inducing test. NMR provides early information on disk degeneration without the complications of an interventionist test. The aim of this study is to determine the effectiveness of diskography as diagnostic technique in lumbar pain of diskogenic origin and to compare diskographic images and NMR, as well as correlation in the pain-inducing test. Material and methods: Sixty (60) disks from 29 patients were assessed between April 2000 and April 2001. All the patients were asymptomatic and had lumbar or lumbosciatic pain. The average period of evolution was 17 months. Mean age was 43 years (range 75-26 years). The study population included 11 men and 18 women. Diskography was divided according to its radiological image in three stages: normal, degeneration and herniation. Classification of pain-inducing test was divided in four stages: absence of pain, non-concordant pain, similar pain and concordant pain. Images obtained through NMR were divided in three stages: normal, degeneration and herniation. Test usefulness for the diagnosis of pain is reviewed, as well as correlation between the two tests both in image and in pain induction. The number of complications associated to diskography is also reviewed. Results: In 35 of 54 levels (64.8%), NMR was adequate in order to predict whether disk morphology was normal or abnormal in the diskography. Of the 23 patients with a complete fissure, all of them except 2 (8.6%) had concordant pain. One of the 10 degenerated disks had a negative test (10%). Three of the disks with no pathology (21 disks) caused pain (14.2%). With NMR, correlation with pain among degenerated disks was present in 8 (sensitivity of 26.6%) and absent in 7 (specificity of 30.4%) with a VVP of 53.3%. Among fully degenerated disks, 24 levels, the test was positive in 19 cases (sensitivity of 63.3%) and negative in 5 (specificity of 78.5%) with a VVP of 79.1%. Among the 15 disks reported as normal by the radiologist, pain was absent in 12 (specificity of 50%) and present in 3 (sensitivity of 50%), with a VVP of 80%. The rate of false positive was 8.6% and the rate of false negative was 3.7%. There were no complications associated to this technique. Conclusion: Diskography cannot be displaced for the diagnosis of lumbar pain of diskogenic origin when the image shows a degenerate disk.