Preserving anus in rectal cancer surgery can be roughly divided into two categories according to the situation:
First, the tumor is located in the middle and high position of the rectum.
The rectum is an intestine about 15- 18 cm long from the anus. We divide it into three sections: high, medium and low. The closer it is to the anus, the lower it is, so the middle and high part of rectum is the intestine about 8 cm away from the anus. Then the tumor grows to more than 8 cm from the anus. Whether it is early, middle or late, surgery is basically allowed to preserve anus. The process of operation is simply to cut off the problematic intestine with tumor and connect the remaining intestines with good ends (anastomosis). This operation is mature and has a long history. Now the development can also be carried out under laparoscopy. If it is done under laparoscopy, the wound of the patient's abdominal wall will be easier to recover. The function of anus preservation is also ideal. The representative of this kind of operation is "Dixon operation" in clinic.
Second, the tumor is located in the low rectum.
As can be seen from the introduction just now, the tumor in this position is about 8 cm below the anus. At the beginning, the intestine in this position has a characteristic that tissues such as muscles grow around and are fixed in the abdominal cavity, so the condition that the two disconnected intestines are connected does not exist. For example, it is like connecting two water pipes. If they are all movable pipes, it is easier to connect them. If one water pipe is buried in the wall and only one hole is exposed, it will be difficult to connect another water-saving pipe. If rectal cancer in this position wants to preserve anus, the condition must be that the tumor is in stage I, because the cancer cells of this early tumor have not spread deep into the intestinal wall. To put it bluntly, its foundation is not deep enough, and it only stays in the shallow position of the intestinal wall and will not affect other tissues in the depth. In this case, the tumor can be removed by surgery. After excision, the muscular layer will not be affected, and the anus can be preserved. The process is to enter the anus through the operating rod to remove the tumor.
However, this kind of anus-preserving surgery has a great disadvantage: in clinic, the preoperative diagnosis can't determine the stage of the tumor 100%, and it is often necessary to continue pathological examination of the tumor samples taken out during the operation to determine the stage, so such patients are likely to find that the tumor is not stage I during or after the operation, and the cancer cells have invaded the deeper position of the intestinal wall. At this time, the tumor tissue can't be removed completely only by the surgical stick entering from the anus, so it is very likely that it will be changed to anal resection in the middle of the operation, or the second operation will be performed after the first operation to ensure the cancer cells are clean. Moreover, the discovery of rectal cancer in China is generally relatively late, and stage I and II are rarely found. Therefore, this kind of surgery is rarely done in clinic.
At present, the anus-preserving operation for low rectal cancer in hospitals is cryoablation. The principle of this medical technology is "freezing cancer tissue at ultra-low temperature, and finally solidifying and necrosis." When the cancer tissue is necrotic, it will naturally fall off (ablate) from the intestinal wall, thus ensuring' resection'. " It can make up for the deficiency that the surgical conditions of low rectal cancer are too harsh to be implemented.
Compared with the traditional scalpel physical cutting, the freezer has been updated for decades, which can ensure the accuracy of the freezing range, and basically ensure that as many cancer tissues need to be removed, as many cancer tissues will be frozen without destroying so many innocent healthy tissues. Moreover, the traditional surgical method is to open the intestine from the abdominal wall and then remove the tumor, while the cryoablation directly enters from the anus and directly acts on the tumor through the cryoneedle without destroying the normal tissues around the abdominal wall and intestine. This can preserve the anus without destroying the function of the anus!
This treatment has the following advantages:
1, spinal anesthesia (lower body anesthesia only) or local anesthesia (anus and rectum anesthesia only) was used to pass through anus, and the cryotherapy head was in direct contact with tumor tissue. Therefore, even if the patient suffers from serious basic diseases such as hypertension, diabetes, lung disease, etc. He can bear this kind of treatment because it does little harm to the patient's health, similar to hemorrhoids surgery.
2. Tumor tissue in rectum is directly frozen through anus. After being treated for necrosis, the cancer tissue will naturally fall off (ablate) from the intestinal wall, thus solving the problem of intestinal obstruction. Even if the rectal cancer recurs after treatment (the recurrence rate is the same in other aspects), the problem can be solved again by this method.