Sigmoidoscopy is a diagnostic test aimed at visually exploring the anus, rectum and the terminal tract of the colon, called the sigmoid or sigmoid colon. Thanks to a flexible probe, inserted through the anal orifice and equipped at its end with a camera and light source, the doctor can appreciate on the special monitor the state of health of the mucosa that covers these intestinal tracts internally. Furthermore, during the sigmoidoscopy the operator has the possibility of removing polyps or samples of abnormal tissue, useful for a subsequent microscopic examination and for therapeutic purposes.
Colorectal cancers
Colorectal cancer is the second leading cause of death in the Western world. Fortunately, if found and treated in the early stages it is curable in more than 90% of cases. Screening tests - such as fecal occult blood, sigmoidoscopy and colonoscopy - ensure timely diagnosis, significantly reducing incidence and mortality. Even if unwelcome to the patient, colonoscopy and sigmoidoscopy allow you to fight:
- early stage tumors, diagnosing and treating them with less traumatic and more effective therapies;
- tumors still confined to the polyp, diagnosing and removing them on an outpatient basis during the examination itself, without the need for surgery;
- polyps that can turn into malignant tumor, diagnosing and removing them during the examination, without the need for surgery;
These last two points are not satisfied by the virtual colonoscopy.
People reluctant to the idea of undergoing sigmoidoscopy and / or colonoscopy should know that in an advanced stage colorectal cancer determines the formation of secondary tumors (metastases) in the abdominal organs, first of all the liver, making it necessary the partial or total removal of the intestinal tract involved and of any metastases This intervention, in addition to significantly worsening the patient's quality of life, is not always decisive.
Sigmoidoscopy is therefore of "enormous importance in the diagnosis and screening of colorectal cancer, proving also useful in the investigation of intestinal symptoms such as abdominal pain and cramps, rectal bleeding, constipation or chronic diarrhea, frequent alterations of the" alvo (periods constipation alternating with diarrheal episodes), iron deficiency anemia of unknown origin, tenesmus (sensation of incomplete evacuation of stool), emission of ribbon-like excrement and abundant presence of mucus in the stool. For all these reasons, sigmoidoscopy is in effect a simplified version of the best known, but also more invasive, colonoscopy; this last diagnostic procedure, in fact, examines the entire large intestine, resulting therefore more accurate but also more invasive and annoying for the patient; compared to sigmoidoscopy it is also burdened by a higher rate of complications, which however remains very low (approximately 3 cases per thousand tests).
Statistically speaking, despite the enteric tracts examined by sigmoidoscopy represent less than half of the total length of the large intestine, they are home to about 60-70% of benign and malignant tumors. For this reason, numerous guidelines agree in "entrusting the screening. of colon cancer to the coupled sigmoidoscopy / search for occult blood in the faeces, reserving the colonoscopic examination for the evaluation of positive cases. In particular, from the age of 50 it is recommended to carry out a search for occult blood in the faeces every two years, while between the ages of 58 and 60 it is important to undergo a rectosigmoidoscopy to be repeated every decade. However, in the presence of familiarity with the pathology, these screening tests can be recommended already at an early age and more frequently.
Alternative names: rectosigmoidoscopy, proctosigmoidoscopy; the adjective flexible refers to the probe used, which before the advent of microtechnologies was rigid, without a camera and based on "Spartan" procedures and instruments, very similar to those described in the article dedicated to rectoscopy.
Is sigmoidoscopy painful? How is it performed and how do you prepare for the exam?
The sigmoidoscope, with a diameter of about one centimeter, is gently inserted through the anus, after adequate lubrication and digital inspection. During the examination, the patient lies on his side, usually the left one, with his knees bent towards his chest; as a rule, the procedure does not cause significant pain and therefore does not require the use of painkillers; the use of sedatives may however be necessary in the face of a particularly anxious patient. During the examination it is possible to feel sensations of pressure, air movements and evacuative stimuli; in fact, through the sigmoidoscope, the doctor insufflates carbon dioxide to stretch the intestinal walls and obtain a better overview of them. This operation is also responsible for transient meteorism and abdominal cramps that occur at the end of the investigation.
Sigmoidoscopy takes an average of 10-20 minutes and there is usually no need for anesthesia or sedation. If the latter is necessary, the doctor may ask the patient to stay in the hospital for an "hour or more, in order to" dispose of "the effect of the drug; at the same time he will advise against driving the car, recommending rest for the rest of the day.
The "standard" preparation for sigmoidoscopy consists in "performing a single or double evacuative enema at home two hours before the procedure. This" operation is necessary to clean the walls of the final section of the intestine, thus preventing residues fecal hide the underlying mucosa. The methods of preparation are suggested by the digestive endoscopy center and can vary from clinic to clinic; instead of the enema, for example, a liquid diet can be prescribed in the 12-24 hours preceding the appointment, assisted by a laxative to be taken the evening before or the following morning if the appointment is fixed in the afternoon (in these cases the preparation for sigmoidoscopy is similar to that described for colonoscopy).
