Transdermal midline approach for ganglion impar block via the sacrococcygeal junction under fluoroscopic guidance: step-by-step technique

Abstract

Introduction
Chronic pain affecting the coccygeal, perineal, or sacral regions can be severely disabling and may originate from trauma, malignancy, surgery, or idiopathic causes. The ganglion impar, also known as the ganglion of Walther, is the terminal convergence of the bilateral sympathetic chains, located anterior to the sacrococcygeal junction. This report aimed to describe a safe, fluoroscopy-guided midline transdermal approach to the ganglion impar through the sacrococcygeal junction and demonstrate its applicability in treating chronic pelvic and perineal pain.
Technique
With the patient in the prone position and a pillow under the pelvis, the sacrococcygeal junction is identified under anteroposterior fluoroscopy. After local infiltration, a 22G spinal needle is inserted vertically along the midline and advanced through the sacrococcygeal ligament into the presacral space. Proper needle positioning is confirmed in lateral view. After negative aspiration, contrast is injected to confirm spread in the retroperitoneal space. A therapeutic injection (e.g., ropivacaine with dexamethasone) or pulsed radiofrequency (42°C, 120 seconds) may then be performed, depending on the indication.
Conclusion
The midline transdermal approach via the sacrococcygeal junction offers a direct, reproducible, and minimally invasive method for accessing the ganglion impar. It minimizes risk to adjacent structures and should be considered a first-line technique for sympathetic blockade in patients with chronic coccygeal, perineal, or pelvic pain refractory to conventional treatments.