The End-scan Convex Array Probe Is Used To Locate The Internal Orifice Of The Male Anal Fistula Before Perineal Ultrasound

Objective:The structure of male anal canal was observed by perineal ultrasonography with end-scan convex array intracavity probe.Anal mucosa,internal sphincter,external sphincter and perianal tissue were displayed.The position of the internal orifice of anal fistula and the relationship between the fistula and the sphincter were examined.The characteristics of ultrasonography were analyzed.The external orifice and fistula were observed with high frequency linear array probe.The purpose of this method was to explore the diagnostic value of this method for anal fistula and to explore the end-scan convex.The diagnostic value of intraperineal probe for internal orifice was evaluated,and the clinical application value of ultrasonography in the diagnosis of anal fistula was evaluated,in order to provide another ultrasonographic diagnostic method for clinical examination of anal fistula and to guide clinical treatment.Methods:36 male patients with anal fistula who met the inclusion criteria were examined by ultrasonography.Perineal sphincter and surrounding tissues were scanned by end-scan intracavity probe with frequencies of 3-10 MHz.The position and size of the internal orifice of anal fistula were observed.The internal orifice of anal fistula was described by clock method on the transverse section of anal canal.The external orifice and fistula were examined by high-frequency linear probe with frequencies of 5-12 MHz.The accuracy of ultrasonography in the diagnosis was studied by comparing with the results of operation.In addition,15 healthy volunteers were examined for anal canal structure and ultrasonographic segmentation.Results:Case group:(1)36patients were able to tolerate the examination.End-scan convex array intracavity probe could display the transverse section of the anal canal,clearly showing the anal mucosa,internal sphincter,external sphincter and perianal tissue.(2)The coincidence rate of high frequency linear array probe ultrasonography in diagnosis of anal fistula was 97.22%(35/36).The typical sonographic features were hypoechoic oblique passage of anal canal in subcutaneous soft tissue around the anus.The dynamic observation of the probe pressure showed fluid flow when combined with abscess.(3)End-scan convex array intracavity probe can clearly show the internal and external anal sphincters by perineal ultrasonography.The internal orifice ultrasonography shows the high echo interruption defect of the longitudinal anal muscles,and the interruption defect continues with the low echo fistula.Thirty-six patients with anal fistula were confirmed by operation with 38 internal orifices,33 internal orifices were detected by preoperative ultrasonography,3 internal orifices of simple anal fistula were missed,1 of 2 internal orifices of complex anal fistula was missed,and 1 internal orifice of simple anal fistula was misdiagnosed as normal gland canal.The coincidence rate of diagnosing internal orifice of anal fistula by perineal end scan ultrasonography was 86.84%(33/38).(3)End-scan convex array intracavity probe has high accuracy in preoperative diagnosis of anal fistula.Healthy group:15 cases of normal group can clearly show the whole process of anal canal through perineum,the transverse section of anal canal is round,three echoes,the outer layer is high echoes external sphincter,the middle layer is low echoes internal sphincter,the center is high echoes mucosa.The anal canal is divided into three segments.There is no obvious demarcation between the external anal sphincter and the puborectal muscle on ultrasonography.The morphological distinction shows that the puborectal muscle has U-shaped high echo and the internal sphincter has circular low echo as the upper segment The external and internal sphincter have closed high echo and low echo as the middle segment The lower segment shows the subcutaneous high echo of the external anal sphincter.Conclusions:(1)End-fire endoprob intracavity probe can be used to observe the structure of anal canal in real time and dynamically by perineal ultrasound.The method is simple,fast and non-invasive,and has high clinical value.(2)End-fire endoprob intracavity probe can be used to detect the internal orifice of anal fistula and part of the fistula in the sphincter by perineal ultrasound.The relationship between the internal orifice of anal fistula and the sphincter has good practicability in clinic.It can be used as a method of ultrasound examination of anal fistula.