1. 2017;20;E823-E828Repeated Ganglion Impar Block in a Cohort of 83 Patients with Chronic Pelvic and Perineal Pain
   Retrospective Study
   Quentin-Come Le Clerc, MD, Thibault Riant, MD, Amelie Levesque, MD, Jean-Jacques Labat, MD, Stephane Ploteau, MD, Roger Robert, MD, Marie-Aimee Perrouin-Verbe, MD, and Jerome Rigaud, MD, PhD.

BACKGROUND: The ganglion impar is the first pelvic ganglion of the efferent sympathetic trunk that relays pelvic and perineal nociceptive messages and therefore constitutes a therapeutic target.

OBJECTIVE: The objective of this single-center study was to evaluate the effectiveness of 3 repeated ganglion impar blocks in patients with chronic pelvic and perineal pain on intention-to-treat.

STUDY DESIGN: Retrospective single-center study.

SETTING: We reviewed the medical records of 83 patients with chronic refractory pelvic and perineal pain. On intention-to-treat analysis, 62 (74.7%) of the patients received 3 ganglion impar blocks.

METHODS: Ganglion impar block was performed with 0.75% ropivacaine via a lateral approach over the Co1-Co2 coccygeal joint with computed tomography (CT) guidance. The effectiveness of ganglion impar blocks was evaluated by visual analogue scale (VAS) before and 30 minutes after the blocks. Evaluation at least one month after the block was also performed by Patient Global Impression of Change (PGI-C).

RESULTS: A total of 220 blocks were performed, 193 (87.7%) of which were considered to be positive with immediate but transient improvement of pain by more than 50% and complete but transient pain relief after the procedure in 119 (54.1%) procedures. The variation of the VAS score before and after each block was statistically significant (P < 0.001). Similarly, the VAS score before repeated blocks was significantly improved with decreased pain intensity over time (P = 0.001). Analysis of the PGI-C one month after the block demonstrated improvement in 41% of cases in the overall population and in 43.6% of cases in the subgroup of 62 patients treated by 3 blocks.

LIMITATIONS: Retrospective study, short term follow-up.

CONCLUSIONS: Repeated ganglion impar blocks allowed short-term reduction of pain intensity with a moderate intermediate-term effect. Ganglion impar appears to be a useful therapeutic target to block the nociceptive message by acting on sensitization phenomena.

Key words: Pudendal neuralgia, impar block, pain, perineal, coccygodynia