title: Ultrasound-guided ganglion impar block: a technical report.
abstract: OBJECTIVE
  Ganglion impar block is an uncommon procedure that has been performed traditional with fluoroscopy. One approach is the trans-sacrococcygeal approach. Sometimes this can be difficult because the sacrococcygeal joint (SCJ) cannot be readily seen on anteroposterior (AP) and lateral fluoroscopy. This technical report describes the feasibility of ultrasound in assisting ganglion impar blocks.
  
  
  METHODS
  We performed ganglion impar block using ultrasound as the primary imaging tool, with fluoroscopic confirmation in 15 patients. We used a linear array transducer (5-12 MHz) to obtain sonographic transverse and longitudinal views at the sacral cornua; we identified the first cleft below the sacral hiatus as the SCJ. Then we inserted a 23-gauge (7 cm in length) needle into the SCJ under sonographic guidance. Then we confirmed proper needle depth by lateral fluoroscopy and injection of contrast agent.
  
  
  RESULTS
  In all 15 procedures, we accurately located and passed the needle into the patients' SCJs under real time sonographic guidance.
  
  
  CONCLUSIONS
  In cases where the cleft cannot be readily seen on AP and lateral fluoroscopy, we have found ultrasound to be of assistance. Ultrasound does not replace fluoroscopy, because lateral fluoroscopy is still required to establish safe depth, and correct site of injection. However, ultrasound can be helpful when fluoroscopy alone is insufficient.
authors.affiliation: Department of Anesthesiology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Chia-Shiang
authors.initials: CS
authors.lastname: Lin
authors.forename: Jen-Kun
authors.initials: JK
authors.lastname: Cheng
authors.forename: Yung-Wei
authors.initials: YW
authors.lastname: Hsu
authors.forename: Chien-Chuan
authors.initials: CC
authors.lastname: Chen
authors.forename: Hsuan-Chih
authors.initials: HC
authors.lastname: Lao
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Huang
authors.forename: Peter H
authors.initials: PH
authors.lastname: Cheng
authors.forename: Samer
authors.initials: S
authors.lastname: Narouze
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D005471:Fluoroscopy; D005728:Ganglia, Sympathetic / Q000000981:diagnostic imaging*; D005730:Ganglionic Blockers / Q000008:administration & dosage; D006801:Humans; D009339:Needles; D009407:Nerve Block / Q000379:methods*; D016684:Prone Position; D012445:Sacrococcygeal Region / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D005730:Ganglionic Blockers