Oblique “Scotty dog” versus antero-posterior (AP) views in performing x-ray guided facet joint injections

Abstract

BackgroundFacet joint pain contributes significantly to lower back pain. Image intensifier x-ray guidance is used to locate the facet joints. This can either be in the oblique “Scotty dog” or antero-posterior views. The aim is to investigate whether improved visualisation of facet joints using the oblique method would increase the accuracy of the injection and hence lead to enhanced pain relief effect when compared to AP views in Lumbar facet joints. MethodsSingle centre, single blinded. A total of 42 consecutive patients were recruited between December 2014 and March 2015 at Colchester General Hospital. Patients randomly allocated into facet joint injections using the oblique or AP projection. Pre-operatively the patients were asked to rate their back pain using a numerical 11 point pain rating scale in the questionnaire. Post-operatively patients were seen at 6 weeks and once again were asked to fill out the afore mentioned questionnaire. The results were collated and statistical analysis performed using Microsoft Excel. Results29 patients returned their post-op questionnaire at approximately 6 weeks post-op. 12 patients had oblique view and 17 patients had AP view. There was a statistically significant difference in the pain scores comparing pre and post op scores for both the Oblique and AP groups. However, there was no significant difference when comparing the post-op pain scores or the absolute changes in pain scores between the two groups. DiscussionSpinal facet joint injections provide significant relief at the 6 week post-op follow up with no difference between the oblique and AP techniques.