Oesophageal Stent

Project description

Problem

A caustic is a chemical that can damage the tissue it comes in contact with. These materials include household and industrial combustible materials. Although most of the time the face, eyes and limbs are in contact with these substances, but all cases of death occur after swallowing and eating these substances. Consumption of caustic or acidic substances or sewage-dissolving solutions, especially in children, will cause a severe inflammatory reaction in the mucosa, known in the oesophagus as caustic esophagitis, and in the stomach as caustic gastritis, with clinical manifestations such as pain and Burning in the mouth and back of the sternum is accompanied by increased saliva, odynophagia, dysphagia and hematoma.
Treatment of chemical burns of the oesophagus and stomach is one of the major surgical problems that, despite various medical and surgical methods, has not provided specific results and among the treatments performed, there is still no treatment that has been agreed upon. The prevalence of these poisonings has varied in different societies, Iran is at the top of the table because the desired purity is not applied to these substances and are not easily found in the market.

The severity of damage to a caustic depends on the type of substance, the concentration of the solution, the volume, the viscosity, the contact time, the pH of the substance and if swallowed, the presence or absence of food in the stomach. Acidic substances in contact with epithelial cells cause coagulation necrosis and scarring at the site, which prevents penetration and deeper damage.

Due to the relative resistance of the stratified epithelium to coagulation necrosis, sore throat and oesophagus were less likely to occur. Because acids have a very strong odour and cause immediate pain when in contact with the oral mucosa, the amount eaten is usually small. Acids can be absorbed systemically and cause damage to the spleen, liver, bile ducts, pancreas and kidneys. Following oral consumption of caustic soda, little work can be done to reduce the severity of the burn.

Neutralization of the caustic with acid or base is not recommended due to the possibility of further damage due to heat and vomiting should not be done due to the risk of aspiration and re-burn. The best treatment is to use an alternative method and stenting. In oesophageal stenting, a tube is inserted into the oesophagus (throat) to hold the blocked area open. This tube helps swallow solids and liquids. The oesophagus is a muscular tube that connects the back of the mouth to the stomach.

When swallowing, the oesophageal muscles contract and push food toward the stomach. Many physical problems can block part of the oesophagus. This can make swallowing difficult, which in medical terms is a swallowing disorder. When swallowing, there is a feeling of pain or food stuck in the chest. An oesophageal stent helps to reopen the blocked oesophagus and reduce symptoms.

This is done under general anaesthesia or using painkillers. During the operation, the surgeon inserts a long, narrow tube (catheter) into the oesophagus from behind the mouth. He then inserts a folded hollow tube (stent) through the catheter and places it in the proper position in the blocked area. The stent expands toward the walls of the oesophagus and acts as a support. The surgeon then removes the catheter and leaves the stent in place.

Solution

This project deals with the fabrication of metal-polymer stents for use in injuries caused by oesophageal burns. For this purpose, an oesophageal stent is first made using a NiTi memory alloy with a suitable production method. Then the quantitative and qualitative evaluation of the produced stent will be done. For this purpose, X-ray diffraction analysis and scanning electron microscopy analysis are performed on the sample and then the mechanical properties of the produced stent are examined using appropriate mechanical tests such as tensile test and compared with other similar samples.

If the produced samples are suitable and the necessary qualifications are confirmed, a polymer coating is applied on the sample surface to prevent corrosion of the stent, and then the properties of the stent with the coating will be examined again to ensure proper connection of the coating to the stent surface. Ensure sufficient resistance to loads. Finally, the stent generated using finite element software is simulated and its behaviour will be compared with the real sample.