title: Damage to anal sphincter/levator ani muscles caused by operative procedure in anal sphincter-preserving operation for rectal cancer.
abstract: BACKGROUND
  Details of postoperative damage to anal sphincter tonus following sphincter-preserving operation for rectal cancer remain unclear.
  
  
  METHODS
  Postoperative anal tonus was measured using 3-dimensional (3D) vector manometry in 56 patients. Anal length with pressure from any direction was defined as total length (TL). Length with circular pressure (LCP), which is only measurable using 3D manometry, was also evaluated.
  
  
  RESULTS
  In operations associated with low anastomosis, both TL and LCP at rest were significantly shortened when compared with control (high interior resection [HAR]). In particular, degraded LCP at rest was obvious. Anal lengths in squeezing state were preserved except in cases with intersphincteric resection (ISR). Postoperative incontinence score inversely correlated with functional anal length at rest.
  
  
  CONCLUSIONS
  Although the sphincter muscles are mechanically preserved, function of the internal sphincter and subsequent defecatory function can be degraded in cases with operative procedures including surgical maneuvers at the pelvic floor.
authors.affiliation: Department of Surgery, Teikyo University, Chiba Medical Center, Ichihara City, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirano
authors.forename: Keiji
authors.initials: K
authors.lastname: Koda
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kosugi
authors.forename: Masato
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Hideki
authors.initials: H
authors.lastname: Yasuda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000293:injuries* / Q000503:physiopathology; D005242:Fecal Incontinence / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D009129:Muscle Tonus / Q000502:physiology; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology; D012004:Rectal Neoplasms / Q000601:surgery*