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Pressure Increase in Adjacent Discs During Clinical Discography Questions the Methods Validity

Hebelka, Hanna, MD*; Nilsson, Andreas, MSc; Hansson, Tommy, MD, PhD

doi: 10.1097/BRS.0000000000000166
Diagnostics
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Study Design. Observational in vivo clinical study.

Objective. To investigate whether intradiscal pressure is transferred to adjacent discs during clinical discography in subjects with discogenic pain.

Summary of Background Data. Despite the introduction of pressure registration in discography, the validity of the method remains controversial. Discography in vivo in anesthetized pigs has shown that the pressure increase during disc injection is transmitted to adjacent discs. If pressure transmission is confirmed in human spines, it could be a potential source of false-positive discography responses.

Methods. Twenty-five discograms were performed in 9 consecutive patients. A pressure sensor was introduced through a 22-gauge needle into the nucleus pulposus in 2 adjacent discs. Contrast was injected with a manometer (∼0.05 mL/s) into one of the discs, whereas intradiscal pressure was measured simultaneously in both discs. The injection continued until one of the endpoints was reached; concordant pain with an intensity of 5/10 or more, intradiscal pressure of 80 psi (absolute pressure), and/or 3.5-mL contrast volume.

Results. Intradiscal pressure was successfully measured in 22 adjacent discs of which 7 were not filled with contrast and 15 were prefilled from the previous discogram. A mean pressure increase of 13 psi (range, 3–42 psi) was recorded in 55% (12) of the adjacent discs, corresponding to an increase of 62% above baseline. Of discograms inducing pressure transmission, all had Pfirrmann degeneration grade of 3 or more and, of adjacent discs with increased pressure, 75% had degeneration of 3 or more. Maximum pressure in injected discs averaged 35 psi above opening pressure (range, 10–69 psi).

Conclusion. Clinical discography induces a pressure increase in adjacent discs. The induced pressure increase was of a clinically relevant magnitude and was evident despite low absolute pressures in the injected disc. Pressure transmission during discography constitutes a potential major source of false-positive responses, questioning the ability of discography to provoke pain at just a single disc level.

Level of Evidence: 1

During clinical discography, 12 (54%) of the 22 discs adjacent to the discogram displayed a pressure increase of a mean of 13 psi (range, 3–42 psi), corresponding to an increase of 62%. This pressure transmission constitutes a potential major source of false-positive responses, questioning the validity of discography.

*Department of Radiology, Sahlgrenska University Hospital, SU/M and

Department of Orthopaedics, Sahlgrenska University Hospital, SU/S, University of Göteborg, Göteborg, Sweden.

Address correspondence and reprint requests to Hanna Hebelka, MD, Drottning Silvias Barn och Ungdomssjukhus, Barnröntgen, Smörslottsgatan 1, 416 85 Göteborg, Sweden; E-mail: hanna.hebelka@vgregion.se

Acknowledgment date: May 6, 2013. First revision date: October 7, 2013. Second revision date: November 27, 2013. Acceptance date: December 8, 2013.

The device(s)/drug(s) that is/are the subject of this manuscript is/are not FDA-approved for this indication and is/are not commercially available in the United States.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.

The manuscript includes unlabeled/investigational uses of the products/devices listed below and the status of these is disclosed in the manuscript: Sensor for disc pressure measurements.

University of Göteborg (ALF) and Göteborg Medical Society funds were received to support this work.

No relevant financial activities outside the submitted work.

© 2014 by Lippincott Williams & Wilkins