title: Sphincter lesions observed on ultrasound after transanal endoscopic surgery.
abstract: OBJECTIVE
  To assess the morphological impact of transanal endoscopic surgery on the sphincter apparatus using the modified Starck classification.
  
  
  METHODS
  A prospective, observational study of 118 consecutive patients undergoing Transanal Endoscopic Operation/Transanal Endoscopic Microsurgery (TEO/TEM) from March 2013 to May 2014 was performed. All the patients underwent an endoanal ultrasound prior to surgery and one and four months postoperatively in order to measure sphincter width, identify sphincter defects and to quantify them in terms of the level, depth and size of the affected anal canal. To assess the lesions, we used the "modified" Starck classification, which incorporates the variable "sphincter fragmentation". The results were correlated with the Wexner incontinence questionnaire.
  
  
  RESULTS
  Of the 118 patients, twelve (sphincter lesions) were excluded. The results of the 106 patients were as follows after one month: 31 (29.2%) lesions found on ultrasound after one month, median overall Starck score of 4 (range 3-6); 10 (9.4%) defects in the internal anal sphincter (IAS) and 3 (2.8%) in the external anal sphincter (EAS); 17 patients (16%) had fragmentation of the sphincter apparatus with both sphincters affected in one case. At four months: 7 (6.6%) defects, all in the IAS, overall median Starck score of 4 (range 3-6). Mean IAS widths were 3.5 mm (SD 1.14) preoperatively, 4.38 mm (SD 2.1) one month postoperatively and 4.03 mm (SD 1.46) four months postoperatively. The only statistically significant difference in sphincter width in the IAS measurements was between preoperatively and one month postoperatively. No incontinence was reported, even in cases of ultrasound abnormalities.
  
  
  CONCLUSIONS
  TEO/TEM may produce ultrasound abnormalities but this is not accompanied by clinical changes in continence. The modified Starck classification is useful for describing and managing these disorders.
authors.affiliation: Laura Mora López, Xavier Serra-Aracil, Salvador Navarro Soto, General and Digestive Surgery Service, Parc Tauli University Hospital, Universidad Autonoma Barcelona, 08208 - Sabadell - Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Mora López
authors.affiliation: Laura Mora López, Xavier Serra-Aracil, Salvador Navarro Soto, General and Digestive Surgery Service, Parc Tauli University Hospital, Universidad Autonoma Barcelona, 08208 - Sabadell - Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Serra-Aracil
authors.affiliation: Laura Mora López, Xavier Serra-Aracil, Salvador Navarro Soto, General and Digestive Surgery Service, Parc Tauli University Hospital, Universidad Autonoma Barcelona, 08208 - Sabadell - Barcelona, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Navarro Soto
mesh_terms: D001003:Anal Canal / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D019160:Endosonography; D005242:Fecal Incontinence / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D011183:Postoperative Complications / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D000067368:Transanal Endoscopic Surgery / Q000009:adverse effects*; D016896:Treatment Outcome
keywords: Anal continence; Endoscopic ultrasound; Sphincteric lesions; Starck classification; Transanal endoscopic surgery