title: A randomized clinical study on postoperative pain comparing the Polysoft patch to the modified Kugel patch for transinguinal preperitoneal inguinal hernia repair.
abstract: OBJECTIVE
  The transinguinal preperitoneal approach is a relatively new technique for inguinal hernia repair. Two types of memory-ring mesh are available in Japan: the modified Kugel patch (MK) and the Polysoft patch (PP). We tested the hypothesis that the PP is noninferior to the MK with respect to chronic postoperative pain.
  
  
  METHODS
  An unblinded randomized controlled trial was conducted to assess the noninferiority of PP compared to MK with a 5 % noninferiority margin. A total of 442 inguinal hernia patients operated on from November 2010 to December 2012 were included in this study. The primary endpoint was the pain score assessed by the visual analog scale (VAS) (0-1 vs. 2-10) 1 year after surgery.
  
  
  RESULTS
  The patients were randomized to the PP and MK groups (n = 221 each). One year after surgery, 206 patients (95.4 %) in the PP group and 182 patients (89.6 %) in the MK group rated pain at 0-1 on the VAS scale. According to this rating, the PP group appeared not to be inferior to the MK group (95 % confidence interval, 0.7-10.7 %, P < 0.05). Furthermore, crude superiority tests, adjusting for 1 month of pain, denoted that the outcomes were significantly improved with the PP compared to the MK.
  
  
  CONCLUSIONS
  The use of the PP was noninferior to the MK with respect to the severity of postoperative chronic pain scores 12 months after surgery.
authors.affiliation: Okinaga Clinic, Shimizu-cho 1-10, Itabashi-ku, Tokyo, 174-0053, Japan. kota@khe.biglobe.ne.jp.|Shin-Itabashi Clinic, Itabashi 4-4-4, Itabashi-ku, Tokyo, 173-0004, Japan. kota@khe.biglobe.ne.jp.
authors.forename: Kota
authors.initials: K
authors.lastname: Okinaga
authors.affiliation: Department of Surgery, Terada Hospital, Ohgi 1-20-12, Adachi-ku, Tokyo, 123-0873, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hori
authors.affiliation: Department of Surgery, Teikyo University Hospital, Kaga 2-11-1, Itabashi-ku, Tokyo, 173-8605, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inaba
authors.affiliation: Teikyo University Graduate School of Public Health, Kaga 2-11-1, Itabashi-ku, Tokyo, 173-8605, Japan.
authors.forename: Kazue
authors.initials: K
authors.lastname: Yamaoka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006552:Hernia, Inguinal / Q000601:surgery*; D059685:Herniorrhaphy / Q000009:adverse effects* / Q000379:methods*; D006801:Humans; D015994:Incidence; D007264:Inguinal Canal; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000453:epidemiology* / Q000209:etiology* / Q000517:prevention & control; D010537:Peritoneum; D012720:Severity of Illness Index; D013526:Surgical Mesh / Q000009:adverse effects*; D013997:Time Factors; D055815:Young Adult
keywords: Inguinal hernia; Modified Kugel patch; Polysoft patch; Postoperative pain; Transinguinal preperitoneal approach