The role of transperineal ultrasonography in the assessment of the internal opening of cryptogenic anal fistula.
OBJECTIVE
The aim of this study was to assess the reliability of transperineal ultrasonography (TPUS) in the pre-operative identification of the internal opening of anal fistulas compared to conventional proctological examination and operative findings.


METHODS
Forty-three patients with anal fistula were assessed by TPUS with and without the use of hydrogen-peroxide injection (E-TPUS) in an attempt to identify the internal opening. Results were compared to preoperative conventional examination and operative findings.


RESULTS
Operative assessment showed an anterior internal opening in 29 patients (67.4%) and a posterior opening in 14 (32.6%). Compared to the operative findings, the agreement rate for the identification of the internal opening was 74.4% for physical examination alone, 93.0% for TPUS and 90.7% for E-TPUS. Physical examination was less accurate in detecting the internal opening than both TPUS (p=0.014) and E-TPUS (p=0.026).


CONCLUSIONS
TPUS and E-TPUS are superior to physical examination in the identification of internal openings in anal fistulas. Hydrogen peroxide injection does not provide additional advantages.
Kleinübing
H
H
Department of Colo-Proctology Hospital Municipal São José, Universidade da Região de Joinville, São José, Brazil. hkleinubing@terra.com.br
Jannini
J F
JF
Campos
A C L
AC
Pinho
M
M
Ferreira
L C
LC
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage; D007267:Injections; D008297:Male; D008875:Middle Aged; D010502:Perineum; D011300:Preoperative Care / Q000379:methods; D012003:Rectal Fistula / Q000000981:diagnostic imaging* / Q000601:surgery; D015203:Reproducibility of Results; D014463:Ultrasonography
D006861:Hydrogen Peroxide