IMSS urologist developed a device to practice percutaneous nephrolithotomy (procedure used to remove kidney stones from the body when they can’t pass on their own), avoiding X-ray radiation exposure.

Commonly known as kidney stone or urinary calculi, urolithiasis is a painful and common disorder among the population. It is a health problem associated with age, gender, and ethnicity; as well as diet and lifestyle, such as low levels of water intake, and high sodium, calcium and animal protein consumption.

When kidney stones are large, the traditional method of dealing with this problem is through open surgery (incision in the abdomen to reach the kidney and remove stones), but in recent decade a common treatment is percutaneous nephrolithotomy, a minimally invasive surgical procedure.

According to Efrain Maldonado Alcaraz, medical specialist in urology at the Specialties Hospital of the ‘Siglo XXI’ National Medical Center part of the Mexican Institute of Social Security (IMSS), patients who undergo percutaneous nephrolithotomy have a speedy recovery compared to those they had an open surgery; however, realize it requires a lot of precision, appropriate training and experience of the surgeon.

The ‘Siglo XXI’ National Medical Center is one of the Mexican public institutions where more urinary calculi surgeries are performed annually (about 30 to 40 per week), so it is also training center in percutaneous nephrolithotomy.

A problem with percutaneous nephrolithotomy is that surgeons practicing and training to perform it have a constant exposure to an X-ray dose, used in this type of surgery to improve the accuracy of access to the kidney through fluoroscopic control. “This surgery has a major problem: urologists are afraid to practice it. Additionally, the people who are learning to perform the surgery receive radiation doses every time they practice it. The cumulative radiation generates cancer for the teacher and the trainee,” Maldonado Alcaraz said.

According to the IMSS specialist, the trainee doctor can receive a radiation dose between 1 millisievert (mSv) and up to 6mSv per surgery, as the dose varies accordingly the technical difficulty of the procedure. If this figure is added the number of procedures the doctor performs during training (25 or 30 cases), he could exceed 20mSv maximum dose of occupational exposure per year recommended by the International Commission on Radiological Protection (ICRP).

Due to this background, Maldonado Alcaraz and his team developed a renal percutaneous puncture training device, called iPERC. This allows the training surgeon have adequate orientation to target sites of percutaneous access to the kidney, preventing radiation exposure.

The training device replaces the use of X-rays by a white light that emits no radiation, but exerts the same function as fluoroscopy in training. iPERC is a small box that makes movements from 0 to 30 degrees, and simulates the arc C for surgical procedures. On the upper surface of the tool a mobile device is placed with a camera to record video, allowing surgeons to visualize the maneuvers in real time.

Inside the small box a three-dimensional model made of resin is placed, which has an electric circuit. It has an electrode exactly at the point where the doctor will have to puncture. The tool has a pedal for the activation and deactivation of a white light that emits no radiation. When a perfect puncture is done, the tool emits an LED light; if this does not turn on, the doctor can practice many times without hurting his health, the patient or an animal,” said Efrain Maldonado.

According to Efrain Maldonado, iPERC is a medical innovation that revolutionizes the teaching of nephrolithotripsy percutaneous surgery. He added that training usually is done with pig kidneys, but he said the latter methodology inappropriate.

Practice models currently used are animals, pigs, but not it is not well accepted using animals for this purpose. In addition, the anatomy of the pig is not so similar to the internal passages human kidney. There are other models that use ultrasound and anatomical models that sometimes do not resemble what is done in a human being,” said Maldonado Alcaraz.

iPERC is patent pending in the Mexican Institute of Industrial Property (IMPI). It is also designed for use in other types of surgery. Maldonado Alcaraz has presented this device at the Annual Congress of the European Association of Urology and the Congress of the American Urological Association.


Source: Agencia Informativa CONACYT