Titanium nickel shape memory alloy intestinal stent

The intestine is the longest duct 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, surrounded by the colon. The surface of the intestinal mucosal layer is covered with intestinal villi, mainly for the digestion and absorption of food. Various digestive fluids break down the chyme into glucose and amino acids in the small intestine, allowing the food to be digested and absorbed. The remaining waste forms feces, which are stored in the left colon and excreted from the body.

When the abdomen is narrowed or obstructed due to advanced malignant tumors or other malignant lesions, it can cause difficulties in food digestion, absorption, and defecation. Approximately 850000 new cases of colorectal cancer occur worldwide each year, with 7% to 29% of patients presenting with acute complete or incomplete intestinal obstruction as the first symptom. Due to the presence of obstruction in colorectal cancer, preoperative bowel preparation cannot be performed, making clinical management more difficult. Postoperative complications such as anastomotic leakage and severe infection are prone to occur, making it the most fundamental challenge for surgical management of colorectal cancer obstruction. Many scholars at home and abroad have carried out various methods of intraoperative proximal intestinal decompression and lavage, such as various intraoperative intestinal lavage methods, temporary proximal colostomy, intraoperative transanal intubation for decompression, and postoperative placement of anal canal for decompression. The implementation of the above methods has reduced the incidence of anastomotic leakage after primary resection and anastomosis for left colon cancer obstruction, and has been clinically promoted. However, there are still drawbacks such as prolonged surgery time, contamination of the abdominal cavity, loss of intestinal electrolytes, and disruption of the internal environment.

In recent years, there have been increasing reports both domestically and internationally on the use of various metal stents as intraluminal support for the treatment of malignant obstruction of the colon. This involves placing a mesh like stent at the site of intestinal stenosis to open the intestine and restore patency to the narrowed or obstructed area. This can serve as a permanent or temporary treatment for malignant obstruction of colorectal cancer and create conditions for elective surgery. Intestinal stents are suitable for patients with duodenal, small intestine, colon, rectal stenosis, obstruction, and anastomotic stenosis caused by advanced abdominal malignant tumor invasion, compression, or other malignant lesions. The application of intestinal stents in the treatment of colorectal cancer obstruction mainly includes temporary transitional placement and palliative treatment [9-10]. Palliative treatment is suitable for primary or recurrent colorectal cancer with unresectable local lesions, those who have extensive metastasis or cannot tolerate surgical treatment, in order to relieve obstruction, alleviate the long-term pain of the patient's anal pouch, and improve their quality of life. The transitional placement of intestinal stents can replace colonostomy, provide sufficient intestinal decompression, alleviate obstructive symptoms, and restore the local and systemic pathological and physiological status of obstructive left colorectal cancer patients to or close to a non obstructive state. Then, the primary laparoscopic surgery for simple colorectal cancer can be chosen to reduce surgical complications and mortality, avoid secondary surgical trauma, improve survival rate, and improve patient quality of life.

Intestinal stents are generally made of metal, with titanium nickel alloy being the most commonly used. 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, as well as memory properties and super elasticity. The scaffold is in a softened state in an environment of 0-10 ℃ (or ice water), and its shape can be changed within a certain range, making it easy to insert into the implantable device. When the ambient temperature is above 33 ℃, the stent can be released and gradually return to its original shape, generating a continuous and gentle radial expansion force that acts on the inner wall of the intestine, restoring patency to the narrow area. The stent has good superelasticity at body temperature and can deform with normal intestinal peristalsis, keeping the intestine unobstructed and comfortable.