Position and anatomical landmarks
The patient lies in a prone position on the operating table with a pillow under the pelvis, in such a way that the sacral bone is rotated in a ventral direction. Both cornu of the sacral hiatus are palpated. Thereafter, and more caudally, the sacro-coccygeal joint is marked and palpated.
Figure 1. Needle position for local infiltration of the sacrococcygeal joint: lateral view.
After sterile preparation of the area, the needle (22-G) is inserted (using ultrasound guidance) and 4 ml bupivacaine 0.25% with 40 mg depot corticosteroid is injected near the joint capsule or into the disc of the the sacro-coccygeal joint.
- The most serious complication after the injection is infection.
- Small subcutaneous bleedings may result in a temporary increase in pain after the injection.
- Local anaesthetic injection with corticosteroids always carries the risk of going through the disc and penetrating the rectum.