What Is a Colonic Stent?

Intestinal stent profile

The intestine is the longest tube in the digestive organs, including the duodenum, small intestine, cecum, colon, and rectum, with a total length of about 7m. The small intestine bends back to the center of the abdomen and is surrounded by the colon. The surface of the small intestinal mucosa is covered with intestinal villi, mainly for digestion and absorption of food. Various digestive fluids in the small intestine break down the chyme into glucose and amino acids, making the food After digestion and absorption, the remaining waste forms feces, which are stored in the left colon and discharged out of the body.

When the intestine is narrowed or blocked due to advanced malignant tumors or other malignant lesions in the abdomen, it will cause food digestion and absorption and defecation difficulties. There are about 850,000 new cases of colorectal malignancies worldwide each year, and the first symptoms of 7% to 29% of patients are acute complete or incomplete intestinal obstruction. Due to colorectal cancer with obstruction, intestinal preparation cannot be performed before surgery, clinical treatment is difficult, complications such as anastomotic leakage and severe infection are prone to occur after surgery, which is the most fundamental problem in surgical treatment of colorectal cancer obstruction. Numerous scholars at home and abroad have carried out a variety of intraoperative proximal bowel decompression and lavage methods, such as various bowel lavage methods during surgery, temporary proximal colostomy, intraanal decompression during surgery, After anal canal decompression. The development of the above method has reduced the incidence of anastomotic leakage after left-sided colorectal cancer obstruction after stage I resection and anastomosis, and has been clinically promoted. However, there are still some disadvantages such as long operation time, pollution of the abdominal cavity, loss of intestinal electrolytes and disturbance of the internal environment of the body.

In recent years, reports of the use of various metal stents as intestinal lumen support to treat colorectal malignant obstruction have gradually increased in recent years. Unobstructed, can be used for permanent or temporary treatment of malignant obstruction of colorectal cancer, and create conditions for elective surgery. Intestinal stent is suitable for patients with duodenal, small intestine, colon, rectal stricture obstruction and anastomotic stenosis due to late abdominal malignant tumor invasion, compression or other malignant lesions. The application of intestinal stents in the treatment of colorectal cancer obstruction is mainly divided into temporary transitional placement and palliative treatment [9-10]. Among them, palliative treatment is suitable for primary or recurrent colorectal cancer whose local lesions cannot be resected. Those who have extensively metastasized or cannot tolerate surgical treatment to relieve obstruction, avoid patients suffering from long-term anal pouch, and improve their quality of life. . The transitional placement of the intestinal stent can replace the colostomy, perform sufficient intestinal decompression, alleviate the symptoms of obstruction, and restore the local and systemic pathophysiology of patients with obstructive left colorectal cancer or approach the non-obstructive state Then, we choose the stage I laparoscopic surgery for simple colorectal cancer to reduce surgical complications and mortality, avoid secondary surgical trauma, improve survival rate, and improve patient quality of life.

Complications of stent implantation include intestinal perforation, intestinal bleeding, stent displacement, shedding, and obstruction.

Figure 1. Schematic diagram of intestinal structure

Figure 2. Intestinal stent appearance

Classification of intestinal stents

According to different lesions, intestinal stent can be divided into duodenal stent, small intestine stent, colon stent, and rectal stent according to different positions (as shown in Figure 3). Clinically, different diameter stent should be selected according to the situation of the patient.

Figure 3. Classification of intestinal stents

Characteristics of intestinal stent

In China, the technology of intraluminal stent is relatively mature. The intestinal stent produced by Nanjing Minimally Invasive Medical Technology Co., Ltd. is the most widely used in clinical practice. Has the following characteristics:

(1) Made of titanium nickel alloy, it has excellent biocompatibility and corrosion resistance, and has memory characteristics and super elasticity. It is easy to place in the inserter at a certain temperature. When the stent is released in the body, it can gradually return to its original shape, producing a continuous soft radial expansion force, which acts on the inner wall of the intestine and restores the stenosed patency.

(2) The stent has good superelasticity at body temperature, and can deform with normal intestinal peristalsis, so that the intestinal tract can be kept open without discomfort.

(3) One or both ends of the intestinal stent are cylindrical with a ball or mushroom head shape (as shown in Figure 4). Both ends are smooth without sharp corners or burrs to significantly reduce the damage to the intestinal wall.

Figure 4. Wave-shaped intestinal stent ends reduce push resistance

(4) The intestinal stent has a matching stent inserter (as shown in Figure 5), which allows the insertion and release of the intestinal stent to look directly at the endoscope.

Figure 5. Insertion and release of intestinal stents

Intestinal stent titanium nickel shape memory alloy intestinal stent

Intestinal stents are generally made of metal, and the most commonly used is titanium nickel alloy. Titanium nickel alloy has excellent biocompatibility and corrosion resistance, and is widely used in medical fields, such as: artificial joints, bone plates, and heart occluders. The intestinal stent made of titanium nickel alloy has excellent biocompatibility and corrosion resistance, and has memory characteristics and super elasticity. The stent is in a softened state in the 0-10 ° C (or ice water) environment. The shape can be changed within a certain range, and it is easy to put in the implanter. When the stent is released when the ambient temperature is higher than 33 ° C, it can gradually return to its original shape, producing a continuous soft radial expansion force, which acts on the inner wall of the intestine and restores the stenosed patency. The stent has good super elasticity under body temperature, and can deform with normal intestinal peristalsis, so that the intestinal tract is kept open and free of discomfort.

Figure 3. Intestinal stent appearance

Method for placing intestinal stent stent material

A. Intestinal stent A. Duodenal stent placement method:

Under X-ray monitoring, an ultra-long ultra-smooth guidewire with a diameter of 0.035-0.038 inches is inserted through the duodenal stenosis to the distal small intestine through the mouth or duodenal biopsy hole. Under X-ray monitoring, microwave cauterization was performed through the gastroscope to form a small channel, and then the guide wire was inserted to the distal end. A double-lumen catheter angiography was introduced along the guide wire to observe the stenosis, and a stent of appropriate size was selected. Push the catheter further into the small intestine and replace the soft-tipped super-hard guidewire. The stent-equipped inserter is introduced along the super-hard guide wire, and the distal end of the stent is slowly released about 10mm beyond the narrow section, and gradually adjusted to make the stent in a proper position. After the release, if necessary, exit the implanter, replace the balloon catheter to the stenosis, inject the warm contrast agent at about 50 through the external cavity to expand and shape, and then exit the guide wire and the implanter.

B. Intestinal stent B. Colon and rectal stent placement method:

Under X-ray monitoring, a fiber sigmoidoscopy was inserted through the anus, and a 0.038-inch ultra-long ultra-sliding guide wire was inserted from the biopsy hole through the narrow section to the distal end. A double-lumen catheter angiography was introduced along the guide wire to observe the stenosis, and a stent of appropriate size was selected. After the observation is completed, the soft head and hard guide wires are exchanged. The stents are introduced along the hard guide wire, and the distal end of the stent is slowly released about 10mm beyond the narrow section, and gradually adjusted to make the stent in a proper position. After the release, if necessary, exit the implanter, replace the balloon catheter to the stenosis, inject about 50 warm contrast agent through the external cavity to expand and shape, and then exit the guide wire and the implanter.

Intestinal stents extended reading:

[1] Zheng Chao, Wu Yulian, Li Qing. Preoperative intestinal stent combined with laparoscopic first-stage surgery for 21 cases of obstructive left colorectal cancer [J]. Chinese Journal of Clinical Oncology, 2013, 40 (7): 417-419

[2] Yao LQ, Zhong YS, Xu MD, et al. Self-expanding metallic stents drainage for acute near colon obstruction [J]. World J Gastroenterol, 2011, 17 (28): 3342-3346.
[3] Shen Weihua. Clinical application of one-stage resection and anastomosis combined with transverse colonic iliostomy for acute obstruction of left colon cancer [J]. Journal of Qiqihar Medical College, 2012, 33 (14): 1890-1891.
[4] Pan Qingwen, Zheng Guangyang, Ye Yongsheng. The application effect of stage resection and anastomosis in patients with left half colorectal cancer complicated with acute intestinal obstruction [J]. Journal of Practical Medicine, 2012, 28 (14): 2375-2376.
[5] Zhang Haiyan. One-stage resection and anastomosis of colonic lavage during surgical operation of acute obstructive left colon cancer [J]. China Practical Medical Journal, 2012, 39 (17): 120-121.
[6] Park S, Shin SJ, Ahn JB, et al. Benefits of recurrent colonic stent insertion in a patient with advanced gastric cancer with arcinomatosis causing colonic obstruction [J]. Yonsei Med J, 2009, 50 (2): 296- 299.

[7] Yu Yongyang, Wang Cun, Yang Lie, et al. Analysis of 611 cases of laparoscopic rectal cancer with total mesorectal resection and anus preservation [J]. Chinese Journal of General Surgery (Electronic Edition), 2009, 3 (2) : 493-497.
[8] Chou SQ, Song HY, Kim JH, et al. Dual-design expandable colorectal stent for a malignant colorectal obstruction: preliminary prospective study using new 20-mm diameter stents [J]. Korean J Radiol, 2012, 13 (1 ): 66-72.
[9] Ronnekleiv-Kelly SM, Kennedy GD. Management of stage rectal cancer: palliative options [J]. World J Gastroenterol, 2011, 17 (7): 835-847.
[10] Wi JO, Shin SJ, Yoo JH, et al. Insertion of self expandable metal stent for malignant stomal obstruction in a patient with advanced colon cancer [J]. Clin Endosc, 2012, 45 (4): 448-450.
[11] Ding XL, Li YD, Yang RM, et al. A temporary self-expanding metallic stent for malignant colorectal obstruction [J]. World J Gastroenterol, 2013, 19 (7): 1119-1123.
[12] Lopera JE, De Gregorio MA. Fluoroscopic management of complications after colorectal stent placement [J]. Gut Liver, 2010, 4 (Suppl 1): 9-18.