Determination of the Optimal Angle for Needle Insertion During Caudal Epidural Steroid Injection in Adults Using Ultrasound Imaging

Lumbar back pain is a common disease, which reduces life quality. Caudal epidural steroid injection (CESI) is frequently preferred to relieve lumbar back pain. However, various major complications can be observed due to CESI. A new technique of needle angle should be improved to prevent complications such as intraosseous, intrathecal or intravascular injection during CESI.

Caudal epidural steroid injection is one of the methods frequently used to treat chronic lumbar back pain. The current study aimed at examining the anatomy of the sacral hiatus and determining the optimal angle of the needle for CESI.

The current clinical trial was performed in Diyarbakır Selahaddin Eyyübi State Hospital from January to June in 2017. The study included 150 adult patients (first group = 92 males (%61.3), second group = 58 females (%38.7) aged 18 - 78 years applied to the Algology Polyclinic with ASA-PS classes I and II (the American Society of Anesthesiologists (ASA) physical status classification system). Measurements were taken during the CESI applied under ultrasonography (USG) guidance of the intercornual distance, the sacral space, and the optimal needle entry angle.

The intercornual distance was significantly higher in group one (mean ± standard deviation (SD): 16.6 ± 2.04) than group two (mean ± SD: 15.8 ± 2.51) (P < 0.049). No difference was observed between group one (mean ± SD: 4.49 ± 0.75) and group two (mean ± SD: 4.45 ± 0.88) with respect to sacral space (P > 0.79). The most appropriate entry angle for the needle in the application of CESI was mean 71.04° in the whole patient group, as 71.9° in group one and 69.7° in group two. There was no significant difference between the genders in terms of the mean optimal angle (P > 0.091). Also, no significant difference was observed among the patients in terms of the demographic data (P > 0.05).

The results of the current study revealed that the optimal needle angle for CESI applied under USG guidance was 71.04°, different from traditional method and the injection procedure could be safely made directly to the epidural space without changing the angle after entry of the needle to the epidural space