VALIDATION OF ULTRASOUND FOR PERFORMING CAUDAL EPIDURAL STEROID INJECTIONS

Abstract

Introduction:  Primary aim of this study was to use ultrasound for performing caudal epidural injections, as ultrasound can provide the clear images of the sacral structures like sacral cornuas and sacral hiatus and can detect the anatomic variations of  the sacrum and sacral hiatus that make caudal epidural injection difficult or impossible. And thus to validate ultrasound for performing caudal epidural injections. Performing Caudal epidural injections solely under the C-Arm guidance carries more risk of  radiation hazard as many a times multiple X-Rays are required while  performing this procedure. In this method we used ultrasound  guidance to identify caudal structures and to insert and advance the  needle in sacral hiatus, as well as to observe turbulence of the injected contrast agent in the sacral canal, but final confirmation of correct placement of needle and filling of contrast  agent in epidural space was done in fluoroscopic view.

Materials and Methods: This was an observational case study. 32 patients (16 male and 16 female  patients)  with low  back pain posted for caudal epidural steroid injection   as per the inclusion criteria were included in this study.  Ultrasound images of the sacral hiatus and bilateral   cornua were obtained by a real-time linear array  transducer. Under the ultrasonography guidance wede fined the procedure successful if the needle was visualised in sacral hiatus, and turbulence of injected   contrast agent in the sacral canal observed and with fluoroscopic view correct placement of needle and filling of epidural space with contrast agent was   confirmed.

Results: The epidurogram showed that the injection was successful in 31 out of 32 patients. In only 1 out of 32 patients filling of contrast agent was not seen in  fluoroscopic view. The mean distance between bilateral  sacral cornua of all 32 patients was found to be 18.30 ±   0.96 mm, the  mean distance between anterior and posterior wall of  sacral hiatus apex area of all 32 patients were found to be 2.93±0.42 mm. In 1 patient in which the filing of contrast agent in epidural space was not seen on fluoroscopic view, distance between the anterior and posterior wall of sacral hiatus in apex area was 1.80 mm which was smallest among all 32 patients. And the distance between bilateral sacral cornua were 18.60 mm. The mean of Body Mass Index (BMI) was found to 26.79± 3.54.

Conclusion: In conclusion, ultrasound could be safe and reliable modality to observe anatomic variations of sacral hiatus and to perform caudal epidural injections.