Gentle transanal endoscopic microsurgery, or TEM, is used to remove smaller carcinomas or adenomas (polyps). This minimally invasive surgical technique in the lower rectum involves placing the patient under either general or spinal anesthesia.
What is transanal endoscopic microsurgery?
Transanal endoscopic microsurgery (TEM) is a modern surgical procedure that can be considered for small tumors or adenomas, also called polyps, in the rectum. Transanal endoscopic microsurgery (TEM) is a modern surgical procedure that can be considered for small tumors or adenomas, also called polyps, in the rectum. The term microsurgery indicates that it is a procedure that does not require a skin incision. In this respect, the TEM procedure belongs to the field of minimally invasive, and thus extremely gentle surgical techniques. To date, this technique is also the only one in endoscopic surgery that allows direct access to the surgical organ. The patient is operated on in the so-called lithotomy position. The patient lies on his back with his legs bent at 90 degrees and his lower legs on supports. The procedure is performed through an endoscope, also called a rectoscope, which is inserted into the rectum. The specially designed surgical instruments, such as a camera and magnifying glass, are also inserted this way to the surgical site. Up to three surgical instruments can be inserted via the rectoscope. The endoscope, which is about 50 millimeters thick, is connected to the operating table by a holding function to ensure a stable construction. The procedure is monitored by video. Important for precise work of the surgeon, is a good view of the surgical field. Therefore, the rectum is dilated with carbon dioxide (CO2). This procedure guarantees a comprehensive overview during the operation. Before the doctor decides on TEM, a colonoscopy and a biopsy (tissue sample) are performed.
Function, effect and goals
Transanal endoscopic microsurgery is used for both benign and malignant diseases of the rectum. Among the benign ones is diverticulitis, an inflammation of the colon in which mucosal outpouchings, although unpleasant for the affected person, form harmlessly. TEM occupies a broad field in the removal of polyps. These adenomas are considered to be precursors of rectal cancer. Consistent screening examinations are therefore an effective cancer prophylaxis to detect adenomas in time, and to tackle their removal. The risk of them developing into a malignant tumor is between 20 and 50 percent, and depends on the tissue type. Therefore, comprehensive preoperative diagnostics are required before surgery. This includes biopsy, colonoscopy and rectoscopy, as well as endosonography of the rectum. Since the procedure can only be performed under general or spinal anesthesia, an EKG is taken and anesthesiological evaluation of the patient is required. The extent of a rectal tumor can be determined either by endorectal sonography. If this is not sufficient, an additional magnetic resonance imaging of the pelvis is recommended. Up to a size of two centimeters, adenomas can still be removed during a colonoscopy using a so-called diathermy snare. Modern transanal endoscopic microsurgery, on the other hand, makes it possible to remove large polyps at an early stage. This also eliminates the need for an abdominal incision or the creation of an artificial anus. This is because a major advantage of the TEM method is that it focuses on preserving the sphincter muscle. This can prevent the anus preter, which is feared by patients. The surgical rectoscope can be used to remove polyps and carcinomas located up to 24 centimeters from the anus. The rectoscope provides very good viewing conditions so that even high rectal tumors can be operated on accurately and reliably. If the tumor is a polyp, a mucosectomy is performed. Here, only the inner layer of the mucosa is removed. If a carcinoma is present, the surgeon will opt for a full-wall excision, in which the tumor itself and a thin margin of healthy tissue are excised. The associated lymphatic tissue remains untouched.The procedure itself is almost bloodless, as the tumors are cut out with a high-frequency current needle. The intestinal wall is then sutured back together.
Risks, side effects and dangers
Because TEM is a minimally invasive surgical method, patient distress is low, as is the complication rate, which is 2.5 percent. No direct pain is felt in the rectal area, so there is little postoperative discomfort. The patient usually does not need painkillers either and can even get up on the day of the operation. He is usually discharged home after about a week. In the rare cases where problems do occur, there may be intestinal perforation, suture insufficiency, or fistula formation. Inflammation in the surgical area has also occurred, accompanied by fever. The doctor prescribes antibiotics against these. However, a new operation is not necessary. Back at home, the patient can eat normally. However, very spicy foods should be avoided at the beginning. After two weeks at the latest, the patient is fully fit again. A follow-up is recommended after about three months. Disadvantages are not to be expected from transanal endoscopic surgery. The adenoma removed during surgery is sent to pathology to verify that the tumor has been completely removed. TEM is a complex procedure that requires experience and tact on the part of the surgeon. Patients should inquire about this in advance of surgery.
