Email updates

Keep up to date with the latest news and content from BMC Musculoskeletal Disorders and BioMed Central.

Open Access Highly Accessed Research article

Zygapophysial joint blocks in chronic low back pain: a test of Revel's model as a screening test

Mark Laslett1*, Birgitta Öberg1, Charles N Aprill2 and Barry McDonald3

Author Affiliations

1 Department of Health and Society: Physiotherapy, Faculty of Health Sciences, Linköpings Universitet, SE-581581-85, Sweden

2 Magnolia Diagnostics, 2718 Cadiz St, New Orleans LA 70115, LA, United States of America

3 Massey University, Institute of Information and Mathematical Sciences, Albany, New Zealand

For all author emails, please log on.

BMC Musculoskeletal Disorders 2004, 5:43  doi:10.1186/1471-2474-5-43

Published: 16 November 2004

Abstract

Background

Only controlled blocks are capable of confirming the zygapophysial joints (ZJ) as the pain generator in LBP patients. However, previous workers have found that a cluster of clinical signs ("Revel's criteria"), may be valuable in predicting the results of an initial screening ZJ block. It was suggested that these clinical findings are unsuitable for diagnosis, but may be of value in selecting patients for diagnostic blocks of the lumbar ZJ's. To constitute evidence in favour of a clinical management strategy, these results need confirmation. This study evaluates the utility of 'Revel's criteria' as a screening tool for selection of chronic low back pain patients for controlled ZJ diagnostic blocks.

Methods

This study utilized a prospective blinded concurrent reference standard related validity design. Consecutive chronic LBP patients completed pain drawings, psychosocial distress and disability questionnaires, received a clinical examination and lumbar zygapophysial blocks. Two reference standards were evaluated simultaneously: 1. 75% reduction of pain on a visual analogue scale (replication of previous work), and 2. abolition of the dominant or primary pain. Using "Revel's criteria" as predictors, logistic regression analyses were used to test the model. Estimates of sensitivity, specificity, predictive values and likelihood ratios for selected variables were calculated for the two proposed clinical strategies.

Results

Earlier results were not replicated. Sensitivity of "Revel's criteria" was low sensitivity (<17%), and specificity high (approximately 90%). Absence of pain with cough or sneeze just reached significance (p = 0.05) within one model.

Conclusions

"Revel's criteria" are unsuitable as a clinical screening test to select chronic LBP patients for initial ZJ blocks. However, the criteria may have use in identifying a small subset (11%) of patients likely to respond to the initial block (specificity 93%).