title: Evaluation of invasiveness in single-site laparoscopic colectomy, using "the PainVision™ system" for quantitative analysis of pain sensation.
abstract: BACKGROUND
  Single-site laparoscopic colectomy (SLC) is increasingly performed for colon cancer. There are few reports on invasiveness in SLC. This study aimed to evaluate the postoperative pain from SLC, as compared to conventional multiport laparoscopic colectomy (MLC).
  
  
  METHODS
  We compared postoperative pain among patients from the SLC group (n = 11) with those from the MLC group (n = 11) who underwent laparoscopic surgery for colon cancer at our institution between May and October 2013. Patients were specifically matched for gender, age, body mass index, tumor size, and performance status. Postoperative pain was evaluated at rest and during mobilization, using a visual analog scale (VAS) on postoperative days (PODs) 1-7, and by postoperative frequency of analgesics; pain intensity was evaluated at rest, using the Pain Vision™ system on PODs 1-7. Other operative outcomes of the two groups were also recorded.
  
  
  RESULTS
  Patient demographics, operative outcomes, time duration before first flatus, and C-reactive protein and WBC count on POD 1 showed no significant differences between groups. Results of sequential VAS during mobilization until POD 7 were significantly less in the SLC group than in the MLC group (p = 0.009). However, sequential VAS at rest did not differ between the two groups (p = 0.11). Measured with the Pain Vision™ system, the difference in pain intensity at rest was statistically significant for the postoperative period (p = 0.003). Total requests for analgesics until POD 7 were reduced in the SLC group compared to that in the MLC group, but lacked statistical significance (three vs. seven, respectively, p = 0.07).
  
  
  CONCLUSIONS
  In both quantitative and objective measurements using the Pain Vision™ system, SLC significantly reduced postoperative pain. SLC is a promising procedure, associated with less invasiveness than MLC.
authors.affiliation: Department of Gastroenterological Surgery Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan, mhiraki@gesurg.med.osaka-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hiraki
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takemasa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Uemura
authors.forename: Naotsugu
authors.initials: N
authors.lastname: Haraguchi
authors.forename: Junichi
authors.initials: J
authors.lastname: Nishimura
authors.forename: Taishi
authors.initials: T
authors.lastname: Hata
authors.forename: Tsunekazu
authors.initials: T
authors.lastname: Mizushima
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
mesh_terms: D000368:Aged; D003082:Colectomy / Q000379:methods*; D003110:Colonic Neoplasms / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000295:instrumentation*; D010149:Postoperative Pain / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D012677:Sensation / Q000502:physiology*; D064232:Visual Analog Scale