The Functional Anaesthetic Discogram: Description of a Novel Diagnostic Technique and Report of 3 Cases

BACKGROUND The diagnostic evaluation of patients with presumed discogenic low back pain is controversial; recent studies have brought the specificity of the traditional technique, provocative lumbar discography, into question. One of the explanations for the relative lack of predictability in treatment outcomes for patients with discogenic low back pain may be a corresponding lack of certainty in the diagnosis. PURPOSE A new diagnostic technique is described for the evaluation of patients with presumptive discogenic low back pain; the cases of 3 patients in whom the technique was used are presented. STUDY DESIGN/SETTING Case report; university practice. METHODS A technique is described in which an anaesthetic catheter is placed into putative symptomatic lumbar discs, the patient elicits his or her typical pain via a position or activity, and anaesthetic or placebo is delivered to the disc. The effect of the injected substance on the patient's pain is then noted. RESULTS In one patient, the new test was confirmatory of the results of the provocative discogram; in two patients, the test results were divergent. CONCLUSIONS These case studies and technical description are presented as a first step in examining this method of preoperative assessment. Further study of the technique will allow us to make more definitive recommendations with regards to its validity and utility. LEVEL OF EVIDENCE Level 4 - Case Series.