title: Three-dimensional endoanal ultrasound for diagnosis of perianal fistulas: Reliable and objective technique.
abstract: OBJECTIVE
  To evaluate accuracy of three-dimensional endoanal ultrasound (3D-EAUS) as compared to 2D-EAUS and physical examination (PE) in diagnosis of perianal fistulas and correlate with intraoperative findings.
  
  
  METHODS
  A prospective observational consecutive study was performed with patients included over a two years period. All patients were studied and operated on by the Colorectal Unit surgeons. The inclusion criteria were patients over 18, diagnosed with a criptoglandular perianal fistula. The PE, 2D-EAUS and 3D-EAUS was performed preoperatively by the same colorectal surgeon at the outpatient clinic prior to surgery and the fistula anatomy was defined and they were classified in intersphincteric, high or low transsphincteric, suprasphincteric and extrasphincteric. Special attention was paid to the presence of a secondary tract, the location of the internal opening (IO) and the site of external opening. The results of these different examinations were compared to the intraoperative findings. Data regarding location of the IO, primary tract, secondary tract, and the presence of abscesses or cavities was analysed.
  
  
  RESULTS
  Seventy patients with a mean age of 47 years (range 21-77), 51 male were included. Low transsphincteric fistulas were the most frequent type found (33, 47.1%) followed by high transsphincteric (24, 34.3%) and intersphincteric fistulas (13, 18.6%). There are no significant differences between the number of IO diagnosed by the different techniques employed and surgery (P > 0.05) and, there is a good concordance between intraoperative findings and the 2D-EAUS (k = 0.67) and 3D-EAUS (k = 0.75) for the diagnosis of the primary tract. The ROC curves for the diagnosis of transsphincteric fistulas show that both ultrasound techniques are adequate for the diagnosis of low transsphincteric fistulas, 3D-EAUS is superior for the diagnosis of high transsphincteric fistulas and PE is weak for the diagnosis of both types.
  
  
  CONCLUSIONS
  3D-EAUS shows a higher accuracy than 2D-EAUS for assessing height of primary tract in transsphincteric fistulas. Both techniques show a good concordance with intraoperative finding for diagnosis of primary tracts.
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Marina
authors.initials: M
authors.lastname: Garcés-Albir
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Stephanie Anne
authors.initials: SA
authors.lastname: García-Botello
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Espi
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Pla-Martí
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Martin-Arevalo
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Moro-Valdezate
authors.affiliation: Marina Garcés-Albir, Joaquín Ortega, Department of General and Digestive Surgery, Hospital Clínico Universitario, 46010 Valencia, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Ortega
keywords: Dimensional endoanal ultrasound; High transsphincteric fistula; Intersphinteric fistula; Perianal fistula; Tridimensional endoanal ultrasound