title: Dorsal penile nerve block for rigid cystoscopy in men: study protocol for a randomized controlled trial.
abstract: BACKGROUND
  Pain is common in men undergoing rigid cystoscopy. Even with the application of a lubricant containing 2 % lidocaine, about 76 % of men suffer from mild to severe pain when undergoing rigid cystoscopy. The most painful part of the procedure for men is when the cystoscope passes through the membranous urethra. Song et al. (Neurourol Urodyn 29:592-5, 2010) did autopsies on males and found that the dorsal nerve of the penis (DNP), the terminal branch of the pudendal nerve, innervates the membranous urethra in 53.3 % of specimens. In addition, the urethral mucosa has branches of innervated DNP. Dorsal penile nerve block (DPNB) is usually used for circumcision in children, and it has been shown to provide effective analgesia for penile surgeries. In this study, we hypothesized that DPNB could reduce the overall pain level in men during rigid cystoscopy.
  
  
  METHODS
  The trial is a prospective, randomized, double-blind, placebo-controlled, single-center trial to evaluate the effectiveness and safety of DPNB in analgesia for men undergoing rigid cystoscopy. Participants will be enrolled and randomly allocated into one of three groups according to the different analgesia regimens: 1) tetracaine gel group (DPNB with saline), 2) DPNB group (DPNB with ropivacaine plus plain lubricant), 3) combination group (DPNB with ropivacaine plus tetracaine gel). The primary outcome of this study is the visual analog scale (VAS, 0-10) for pain at cystoscopic inspection of the external sphincter. VAS scores evaluated at other time points serve as secondary outcomes. Vital signs are secondary outcomes that address the discomfort and pain during the procedure. Furthermore, the incidence of adverse events as secondary outcomes will also be recorded for evaluation of the safety of DPNB in rigid cystoscopy. Clinical assessments will be evaluated prior to DPNB, at administration of the lubricant gel, at cystoscopic inspection of the penile and bulbar urethra, external sphincter, prostate, and bladder, as well as at withdrawal of the cystoscope.
  
  
  CONCLUSIONS
  This research will determine the effectiveness and safety of DPNB in men undergoing rigid cystoscopy. The results of this trial may have important implications for exploring the role of DPNB in analgesia for cystoscopy in men.
  
  
  BACKGROUND
  ClinicalTrials.gov identifier NCT02502487 (6 Jul 2015).
authors.affiliation: Department of Anesthesiology, West China Hospital of Sichuan University, #37, Guoxue Ave., Chengdu, Sichuan, 610041, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Department of Anesthesiology, West China Hospital of Sichuan University, #37, Guoxue Ave., Chengdu, Sichuan, 610041, China.
authors.forename: An-Min
authors.initials: AM
authors.lastname: Hu
authors.affiliation: Department of Anesthesiology, West China Hospital of Sichuan University, #37, Guoxue Ave., Chengdu, Sichuan, 610041, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, West China Hospital of Sichuan University, #37, Guoxue Ave., Chengdu, Sichuan, 610041, China. du_guizhi@yahoo.com.
authors.forename: Gui-Zhi
authors.initials: GZ
authors.lastname: Du
mesh_terms: D000328:Adult; D000577:Amides / Q000008:administration & dosage* / Q000009:adverse effects; D019162:Anesthetics, Combined / Q000008:administration & dosage* / Q000009:adverse effects; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D002681:China; D002985:Clinical Protocols; D003558:Cystoscopy / Q000009:adverse effects*; D004311:Double-Blind Method; D005782:Gels; D006801:Humans; D054327:Lubricants / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010146:Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D010147:Pain Measurement; D011446:Prospective Studies; D060525:Pudendal Nerve; D012107:Research Design; D000077212:Ropivacaine; D013748:Tetracaine / Q000008:administration & dosage* / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000577:Amides; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D005782:Gels; D054327:Lubricants; D013748:Tetracaine; D000077212:Ropivacaine
keywords: Analgesia; Dorsal penile nerve block; Men; Rigid cystoscopy