Clinical Application of LINX

Introduction:

The function of the digestive system is to digest food and to change it into simple absorbable forms. These simplest absorbable forms are then absorbed by various mechanisms, and the metabolic function of the body is fulfilled. Several substances are secreted by various parts of the digestive tract that fulfills the digestion process. Gastric juice is one of the essential components of the digestive process. Around 1.5 liters (5.67 gallons) of gastric juice is produced daily in the human body. This juice is highly acidic in nature. But, in some cases, this may flow into the esophagus and cause damage to the esophageal lining. Such a condition is known as GERD or gastroesophageal reflux disease.

What Is GERD?

GERD, or gastroesophageal reflux disease, is a chronic condition of the gastrointestinal system due to the retrograde flow of the stomach's contents to the esophagus. The pH of the gastric juice is between 1.5 to 3.5. This severe acidic juice causes increased acid exposure to the esophagus and esophageal lumen. As a result, erosion of the esophageal lining causes severe discomfort. Around 18 to 27 percent of the adult population in the United States is suffering from this condition.

Pathophysiology

The main components of gastric juice are hydrochloric acid and different enzymes like pepsin and lipase. The presence of hydrochloric acid is responsible for the acidic nature of the gastric juice. Several protective mechanisms of the stomach are helpful in preventing injury of the gastric tissues due to the acidic contents.

Anti-reflex barrier, a complex anatomical zone, presents the retrograde movement of the acidic contents into the esophagus. This anatomical zone consists of the lower esophageal sphincter, the extrinsic crural diaphragm, and the gastroesophageal flap valves.

Disorder of the lower esophageal sphincter is responsible for this condition. Usually, the lower esophageal sphincter maintains a high-pressure zone. A decreased pressure of the lower esophageal sphincter and lower relaxation of the lower esophageal sphincter is associated with dysfunctioning of the lower esophageal sphincter. Chronic decrease in the lower esophageal resting tone is also another reason responsible for gastroesophageal reflux disorder.

The factors associated with such causes are:

• Endogenous hormones like progesterone in pregnancy and cholecystokinin.

• Medications like calcium channel blockers and nitrates.

• High-fat diet, smoking, chronic alcoholism, and chocolate.

• Hiatal hernia is another factor associated with this disorder. Hiatal hernia causes separation of the crural diaphragm from the lower esophageal sprinter. This causes increased exposure of gastric acid to the esophagus.

• Decreased gastric emptying is another factor responsible for gastroesophageal reflux disorder. Increased retention of acid causes distension and retrograde movement of the acid into the esophagus.

• Increased esophageal sensitivity is another contributory factor in the development of GERD. Thermal, mechanical, and chemical stimuli increase the sensitivity and cause acid movement into the esophagus.

Symptoms

The symptoms of gastroesophageal reflux disorder are:

• Heartburn is the most common symptom of GERD. Patients often complain of chest pain and a burning sensation in the chest radiating toward the throat. Pain is squeezing in nature, most commonly felt in the mid portion of the chest and abdomen. Pain may also radiate toward the back, neck, and jaw.

• Sourness in the back of the mouth, which is most commonly noticed during the morning.

• Erosion of the lingual surface of the teeth and burning sensation in the tongue.

• Increased incidence of throat clearance and hoarseness can be seen.

• Fullness and the presence of a lump in the throat can be felt by the patients.

What Are the Treatment Options for GERD?

The treatment options used for the treatment of GERD are:

• Lifestyle Modifications: Living a healthy lifestyle is the key to getting rid of GERD. Stopping smoking, alcohol, and spicy food is necessary. Along with this, weight reduction and regular exercise are needed.

• Drugs: Proton pump inhibitors are the most common drug used for the treatment of GERD. Drugs like Lansoprazole, Omeprazole, Esomeprazole, and Pantoprazole help to reduce the secretion of acids. Other than this, H2 blockers like Cimetidine and Ranitidine can also be used.

• Surgical Treatment: Different surgical options can be explored. Treatment of a hiatal hernia is one of the main treatment options in GERD cases linked to total hernia. Surgical options like laparoscopic Nissen fundoplication (surgical treatment for tightening the junction between esophagus and stomach) and laparoscopic anterior 180-degree fundoplication can be used for the treatment of GERD. In cases of obese people, gastric bypass surgery can be useful.

What Is Magnetic Sphincter Augmentation (LINX)?

Magnetic sphincters are implantable devices that are used for the treatment of GERD. This ring encompasses the junction of the esophagus and the stomach at the lower esophageal sphincter. These sphincters prevent the backflow of the acidic content by putting resistance. The range of normal intragastric pressure is 5 to 10 millimeters of mercury. The magnetic sprinter exerted around 20 millimeters of mercury pressure in the gastroesophageal junction. This pressure helps to prevent the backflow of the acid. In contrast, the normal peristaltic pressure during swallowing is around 35 to 80 millimeters of mercury. Due to this higher pressure, food can easily bypass the sphincter and enter the stomach.

The commercial name of this sphincter is LINX. These magnetic sphincters are made up of rare earth elements and are covered by titanium bids. The number of beds may vary from 13 to 17. Rings are available in various sizes with a standard diameter of around 1.5 inches.

What Is the Surgical Procedure of LINX?

The sphincter can be placed with the help of keyhole surgery or laparoscopic technique. The patient is positioned in a modified lithotomy position. The abdomen is distended with the help of carbon dioxide, and the inside of the abdomen is approached through the left upper quadrant. Carefully the distal portion of the esophagus is reached, and the size of the ring is measured with the help of the sizing tool. After this, an appropriately sized ring is placed with the help of the sizing tool. After placing the ring, the two ends of this device are brought together and held together by a magnetic clasp.

What Are the Benefits of Magnetic Sphincter Augmentation?

The potential benefits of this procedure are:

1. Uncomplicated surgical procedures with less time for hospitalization.

2. Fewer chances of scar tissue formation due to surgery are also less.

3. Post-operative care is minimal, with less chance of postoperative infection.

4. In case of any complications, the device can be retrieved.

What Are the Complications of LINX?

So far, researchers are unable to find any severe complications related to this procedure. But in certain cases, this process can be avoided. Such conditions are:

1. Pregnancy.

2. Age below 21 years.

3. Severe ulceration and damage to the esophagus due to acid reflux in conditions like Barrett’s esophagus and severe esophagitis.

4. A systemic disorder like scleroderma (a rare disorder that causes hardening and tightening of skin).

5. Patients with severe allergies. Specifically allergic reactions with titanium, nickel, and electrical implants.

Conclusion:

GERD is a serious disorder caused by the retrograde movement of gastric juice in the esophagus. Patients usually complain of symptoms like heartburn, sourness in the throat, and chest pain. Drugs like proton pump inhibitors can be used for the treatment of such conditions. But, curing patients with such traditional treatment approaches can be difficult. LINX is an implantable magnetic sphincter that can be placed at the junction of the esophagus and stomach. This device prevents the backflow of gastric content into the esophagus.