Presented at the 2012 AAPM Annual Meeting « Back

Audit on the Use of "Thumb Pressure" or Volume-Controlled Provocative Discography in Order to Determine Painful Lumbar Disc Level

Leonardo Kapural, MD PhD, lkapural@ccrpain.com¹, Thomas Weber, Fellow², (1) Wake Forest University Baptist Health, Pain Medicine Center, Winston-Salem, North Carolina, (2) Wake Forest University Pain Fellowship program, Winston-Salem, North Carolina

Objective, Design, and Interventions: Discography as a test mimics physiologic disc loads and evokes patient’s pain by increasing intradiscal pressure. The intensity of stimulus can be controlled through the skilled operation of a manometer. A syringe with manual thumb pressure is still utilized by many operators. It is approximated that >80% of practitioners do not use manometry when performing discography. Most abnormal discs will provoke a painful response somewhere between 15 and 50 psi. [1,2]. Normal disc can hurt if pressurized too high with uncontrolled, “thumb” pressurization [3,4]. At > 50 psi, the response must be reported as indeterminate, because it is difficult to distinguish between a pathologically painful disc and the pain evoked from simply mechanically stimulating a normal or subclinically symptomatic disc [5]. To limit false-positives, most discography standards set a pressure criteria of < 50 psi. [6] We tested the ability of experienced discographer (LK) to assess the optimal disc pressurization, without producing excessive intradiscal pressures. Provocative discography was conducted using standard technique. Reading from the inline manometer taken by the assistant after blinded operator reached satisfactory point of disc pressurization (end points pain 7/10, or 3.5ml contrast injected). Patients and Results: Ten lumbar discs were pressurized in three patients. Positive response in 3/10 discs was achieved when intradiscal pressure difference was above 50 psi. Conclusions: Based on 3/10 discs potentially false-positive, we hypothesized that overpressurization of the intervertebral discs happens frequently if manometry control is not used and that in turn can cause false-positive results. References: 1)Derby, R.ISISociety News, 1993;1:8-17. 2)Derby, R., et al.,Spine, 1999. 24(4):364-71. 3)Carragee, E.J., et al.Spine, 1999;24:2542-7 4)Carragee, E.J., et al.Spine, 2000;25(11):1373-80 5)5. Endres, S. and N. Bogduk, C., ISIS, Editor. 2003. 6)Seo, K.-S., et al.Spine J, 2007;7(1):68-73.

Funding: None