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Dr Nicolas Claeys is a surgeon.

He manages pathologies of the digestive tract, the abdominal wall and endocrine glands such as the thyroid.

He also performs obesity surgery (gastric by-pass, sleeve, plicature, …).

His specialty covers proctology (hemorrhoids, anal abscesses, fissures and fistulas).

Dr. Claeys provides 24-hour care for acute pathologies via the emergency services of the Chirec hospitals (appendicitis, perforation of diverticulitis, acute cholecystitis, etc.). He is also an external consultant surgeon for pancreas surgery at the Erasme hospital.

Most of the operations are performed by laparoscopy or robot-assisted surgery.

Dr. Nicolas Claeys performs laparoscopic bariatric procedures such as bypass, sleeve and plicature.

At both the Delta Hospital (Chirec) and the Braine-l’Alleud-Waterloo Hospital (Chirec), a multidisciplinary team – consisting of endocrinologists, cardiologists, pneumologists for the study of sleep, operating room nurses, dieticians, nutritionists and psychologists, without mentioning all of them – is trained in the specific treatment of overweight people.

A coordinator serves as an interface to optimize the complete management of the pathology.

This is the reduction of the volume of the stomach accompanied by a modification of the food circuit.

This is the resection or removal of a large part of the stomach along the greater curvature.

The abdominal wall has areas of weakness which, over time, can develop into hernias whose contents can strangle. Surgical intervention is then necessary and consists of placing a parietal prosthesis to reinforce the abdominal wall.

Between umbilical hernia, crural hernia or ventration, inguinal hernia is the most frequent

This type of surgery is performed on an outpatient basis, meaning that you are hospitalized for only one day.

It is sometimes necessary to remove the gallbladder when it contains stones that are causing symptoms. This procedure is called a cholecystectomy and is performed on an outpatient basis, meaning that you are only hospitalized for one day

This is the permanent or intermittent passage of the upper stomach into the chest through the hiatal orifice. The treatment can be medical or surgical depending on the complaints or response to drug treatments.

The procedure consists of placing the stomach back into the abdominal cavity, and making a valve that prevents acid reflux into the esophagus. This valve is made from the stomach.

This procedure is performed laparoscopically through 5 small incisions


Surgery has a prophylactic role in the case of recurrent episodes of diverticulitis or in the case of complicated diverticulitis. It consists in removing the part of the colon containing the diverticula (colectomy) by laparoscopy

Appendectomy is a surgical procedure that consists in removing the appendix when it is infected, most often because of an obstruction. At the end of the operation, it may be necessary to put in place a drainage system (flap or drain) in order to clean the suffusions due to the infection.

Complicated acute diverticulitis
Emergency surgery is sometimes necessary if antibiotics are not effective or if there is an immediate complication, abscess or perforation causing peritonitis.

Acute cholecystitis
Acute cholecystitis is an inflammation of the gallbladder wall associated with an infection of its contents. This acute infection of the gallbladder is very frequently accompanied by the presence of gallstones. Surgical treatment must be carried out early to avoid complications.

Strangulated hernia
The main risk of a hernia is strangulation. When the hernia opening is narrow, it can happen that a bowel loop, passed through the hernia, cannot be reintroduced into the abdominal cavity. Hernial strangulation is a surgical emergency.

Anal abscess
The treatment of anal abscess, given the significant pain, is emergency surgery and drainage of it.

Dr Nicolas Claeys has been trained to use the operating robot for pathologies that are difficult to reach, such as rectal cancer.

The use of the Da Vinci by a surgeon brings several advantages: its manipulator arms have seven degrees of freedom, which allows greater ease in minimally invasive surgery. They allow a greater precision of gestures thanks to a filtration of the tremors. The surgeon’s movement can be multiplied and thus increase the precision of the gesture. The three-dimensional visualization of the intracorporeal space increases the surgeon’s ease during the operation. During an operation with a Da Vinci, the surgeon benefits from a better comfort than during a classic operation under laparoscopy.

Thyroid pathologies sometimes require surgical resection. This operation requires a minimum of 24 hours of hospitalization.

Mini-invasive parathyroid