© Borgis - New Medicine 4/2006, s. 102-106
*Małgorzata Kołodziejczak, Iwona Sudoł-Szopińska1
The practical use of endosonography in the daily work of a surgeon
Department of General Surgery with Subdepartment of Proctology, Solec Hospital, Warsaw
Head of Department: Jacek Bierca, MD PhD
Head of Subdepartment: Małgorzata Kołodziejczak MD, PhD
1Central Institute for Labour Protection – National Research Institute, Warsaw
Director: Prof. Danuta Karadecka, MD, PhD and Department of Diagnostic Imaging, Medical School, Warsaw, Head of the Dept. Prof. Wiesław Jakubowski, MD PhD
The usefulness of endosonography before an operational diagnosis of proctological diseases is undeniable nowadays. This paper discusses the practical aspect of this diagnostic method, namely, in which situations a surgeon can take advantage of it, and what is more, to what degree the endosonography result can influence the decision about an operation as well as the type of procedure to be applied. The use of endosonography is presented for such diseases as: abscesses and fistulas of the anus, anal sphincter defects and narrowing of the anal canal.
Introducing endosonography has become a breakthrough in the diagnosis of proctological diseases. Although the method has been known since 1956 [1, 2], for the first 30 years it was only used in the diagnosis of tumours of the rectum. Since 1989 it has been used in the diagnosis of inflammatory disorders of the anus and rectum as well as injuries of the anal sphincters [3, 4, 5, 6, 7]. That was when an anal probe with a plastic narrow cone was used for the first time. Thanks to the use of rotation of the probe in the transverse position in relation to the long axis of the anal canal, it was possible to obtain transverse cross-sections of the anal canal as well as the surrounding tissues that measured 360°, which made the morphological assessment of anal sphincters accurate [2, 3] (Fig. 1).
Fig. 1. Endorectal probe with a narrow (diameter 17 mm) plastic cone (BK Medical).
In order to examine the anal canal, different kinds of probes can be used such as: sector-sector, sector-linear and mechanical, also called rotating. The last ones emit waves of frequency measuring 7.0 MHz, which gives high resolution as well as deep penetration and good visualization of tissues surrounding the anal canal in the range of 4 cm from it . Thanks to the insertion of the rotating probe one can get 360° transverse sections of the anal canal and the surrounding tissues, which is of great help in rating anal sphincter defects [8, 9].
The majority of reports connected with ultrasonographic diagnosis are written by specialists of pictorial diagnosis. The presented paper is the result of long-term cooperation of a surgeon with a radiologist. Its goal is to show to what degree endosonography can have an influence on a surgical procedure.
Below, the application of endosonography before operational diagnosis of abscesses and fistulas of the anus, injuries of it as well as narrowing of the anal canal is presented.
Patients who have anal abscesses do not have to have any special diagnosis before an operation. Abscesses located superficially (subcutaneous and ischiorectal) do not cause any diagnostic problems for a surgeon or proctologist. The clinical picture is clear and it includes: pain, high temperature, redness as well as fluctuation of skin and subcutaneous tissue near the anus. In such cases performing endosonography is useless. However, it is different when it comes to abscesses which are located suprasphincterically. The clinical picture is not straightforward. In connection with the anatomical structure of the anal canal, e.g. the lack of pain innervation above the dentate line, a patient with a suprasphincteric abscess does not feel any pain, except the feeling of distension in the anus and rectum. The local symptoms on the anus and anal canal´s side are slight. However, general symptoms dominate such as hectic temperature and the bad condition of the patient. It sometimes happens that the first doctor examining such a patient is a urologist, as the patient suffers from urinary obstruction. That is why a high rectal abscess is difficult to recognize in a clinical examination. It often happens that the final diagnostic checkup is the endosonography.
The examination shows the receptacle of fluid precisely, which is located above the anal sphincters, and it is an examination of choice in the diagnosis of high intrasphincteric (Fig. 2), suprasphincteric and pelvic-rectal abscesses [10, 11, 12].
Fig. 2. High, posterior, intrasphincteric anal abscess.
Anal endosonography has been used during the diagnosis of abscesses and fistulas in the Proctology Department since 1996 and in most cases their endosonographic images coincided with the intra-operative diagnosis. However, looking through the literature, it is hard not to mention the discrepancy between the results. According to those who conducted the checkup, it is possible to reveal all of the abscesses while using endosonography . However, Law et al.  describe some difficulties in endosonographic diagnosis of suprasphincteric and ischiorectal abscesses. In our own material endosonography shows high efficiency as all of the abscesses were detected by this method and then they were confirmed intraoperatively .
A good way of supporting anal endosonography is with transperineal sonography. Thanks to this method it is possible to confirm the presence of an ichiorectal abscess as well as other abscesses located more superficially. Ultrasonography through the perineum is another means of diagnosis among those patients who have strong, painful ailments in whom the insertion of a probe would be simply impossible without an anaesthetic [16, 17, 18, 19].
Comparing the diagnostic effectiveness of anal ultrasonography and transperineal sonography it is necessary to state that anal endosonography is more accurate when it comes to the rating of structures highly located. This is due to the possibility of better visualization of the anatomy of the region to be examined, and especially the interaction between an abscess or fistula of the anus and the anal sphincters. The importance of transperineal sonography increases in the diagnosis of any changes located very superficially, while in anal endosonography it is possible for artefacts to appear that are the result of the presence of air between the probe and anal canal walls shading the endosonographic image. Also, transperineal sonography can be performed by doctors who are not necessarily skilled in endosonography. In our practice these two kinds of approaches are combined, when necessary .
How important it is to recognise that a patient has got a suprasphincteric abscess properly is a fact that unrecognised and untreated can lead to septic complications, which may be life-threatening or in final cases may lead to Fournier´s necrosis of the perineum. It is the worst, although infrequent, sceptic complication of outstaying abscesses. It causes extensive necrosis of peritoneum tissues with recrement. It often coexists with necrosis of the scrotum, caused by bacterial embolisms in vessels. This complication concerns obese people who suffer form diabetes as well as patients with lowered immunity and people with other general illnesses such as tuberculosis, scattered, malignant process or HIV.
To sum up, endosonography enables one to recognise and describe precisely the location of an abscess. It allows a surgeon to decide whether a patient needs to be operated on and, thanks to the precise localisation, what operational tactics ought to be followed, namely, from what approach the operation should be conducted, that is, if an abscess should be opened from the skin side or the anal canal.
Unfortunately, it often happens that a patient with an abscess is taken to emergency during the night, when there is no possibility to perform endosonography. If the patient´s general state allows, it is worth waiting until morning, and then performing the endosonography before the procedure, as it helps in better preparation for the operation, namely, to define the localisation (the type) of the abscess, and to exclude the possible coexistence of a fistula and possible anal sphincter defects.
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