| Objective:Lumbar discogenic pain is a common clinical disease, which severely affects the quality of patient's life. This study's object is to explore and evaluate the clinical significance of pressure-controlled discography in diagnosis of discogenic low back pain.Materials and Methods:From July 2008 to October 2009, pressure controlled discography under C-arm guidance was taken in 52 patients with chronic low back pain which were identified as suspected discogenic by MRI and clinical symptoms. Discography was underwent in 135 discs of 52 patients, including 83 degenerative discs and 52 "good" discs. The pressure of discography, the character of pain and the morphological grade of vertebral disc were observed and recorded. The evaluative criterion of the results of discography included:(1) coincident pain——the character of induced pain is similar to the present symptom;(2) incoincident pain——the character of induced pain is significantly different from the present symptom. (3) Painless. The first manifestation of coincident pain could be assessed as positive, and the second and third manifestation would be assessed as negative. According to Adams' morphological classification of discography, the gradeⅢandⅣwere observed and analyzed principally. However, based on the pressure of discography inducing pain, the discs were divided into four groups:less than 30psi, 30 to 50psi; 50 to 70psi and more than 70psi. By using SPSS 11.0 statistical software, the correlation of pressure of discography and positive proportion was analyzed.Results:One hundred and thirty-five discs were performed by C-arm guided pressure controlled discography successfully. Of 83 degenerative discs,46 discs were assessed with coincident pain,16 discs incocident pain, and 21 discs no pain. The pressure during discography of positive degenerative discs was 36.5±15.7psi; the pressure of negative degenerative discs was 50.5±26.2psi, and the normal discs'pressure was 98.6±3.7psi. A significant difference could be found among the three groups (F=194.78,P<0.001). In different pressure groups, the positive proportions were analyzed byχ2 test, and a significant difference was found as well. But no significant difference was found between the group of less than 30psi and 30 to 50psi (x2=18.437, P<0.001). According to Adams'morphological classification of discography, the discography pressure of gradeⅢandⅣof the positive discs showed a significant difference (x2=4.113, P=0.043). The pressure of disc varied from 30 to 50psi in gradeⅢ, however, that is less than 30psi in gradeⅣ.Conclusion:1. The discography is as a unique "golden standard" for the diagnosis in lumbar discogenic pain. However, because of false positive rate, the sensitivity of the clinical diagnosis can be influenced. As the excessive pressure can result in a disruption of annular fibrosus, which may be lead to higher false positive rate, so that the pressure-controlled during the discography is mandatory. It will be valuable for clinical diagnosis if the pressure below 50psi during the discography.2. During the discography, the morphological classification of discs should be evaluated. It could indicate the degree of the disruption of annular fibrosus, which can affect the pressure of the discography. And it also is contributed to discover the mechanism of lumbar discogenic pain. The morphological character of positive result discs is always AdamsⅢorⅣ.3. For the results of this research, we believe that the mechanism of lumbar discogenic pain including chemical and mechanical factors, and the pressure controlled is necessary in discography. |
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