A minimally invasive technique in which surgeons use robots for hernia repair involving the deep abdominal muscles is now being performed at Houston Methodist.

The procedure, known as transversus abdominis release (TAR), reduces recurrence and complication rates and enables immediate intervention in obese patients, according to Dr. Rodolfo Oviedo, a clinical surgeon at Houston Methodist. The relatively new procedure is only available in select U.S. centers.

"The takeaway is that Houston Methodist can help large numbers of patient who suffer from hernias and need complex repairs because they're considered high risk," says Dr. Oviedo. "The procedure isn't very well known yet, but it's ideal for a lot of patients."

Dr. Oviedo says the TAR procedure is appropriate for roughly half of patients in need of hernia repair. Minimally invasive surgery, he explains, should be invoked for 80% to 90% of such patients.

Hernia repairs are one of the most common U.S. surgeries, performed more than 1 million times annually. They correct the defect that occurs when the intestine or fat juts out of a muscle wall weak spot — like an inner tube protruding in a worn-out tire.

Hernias don't disappear on their own and typically grow larger and more painful. In certain cases, when part of the intestine is trapped in a way that cuts off its blood supply, the condition can lead to death if not treated promptly.

The advantages of robot-assisted laparoscopic surgery

Historically, hernia repair was done by open surgery. That approach leads to complications or recurrence in as many as 30% of patients.

Doctors still use open surgery about a third of the time, but in recent years, the focus has turned to laparoscopic surgery and robotic repair — the latter of which involves the surgeon operating a laparoscope and surgical instruments while seated at a console. The technique can be used for some smaller hernias, as well as to reconstruct the abdominal wall.

In the new procedure, using what's known as a component separation, surgeons cut the connective tissue that envelops the transversus abdominus muscle, which wraps around the lower abdomen like a girdle. The cut releases the tension on the muscle, making it easier to close the hole.

"A big hole is difficult to close," says Dr. Oviedo. "You can put stitches in and close it, but it puts a lot of tension on the abdominal wall — the muscle will expand and can tear that repair. That's the beauty of the component separation — it relieves the tension."

As part of the procedure, surgeons insert a polymer mesh between the muscle layers, which doesn't come into contact with any organs.

Unlike open surgery, in which doctors go through the belly button, robot-assisted laparoscopic surgery begins with incisions through the sides of the stomach. Dr. Oviedo notes that the idea is to stay away from the hernia itself.

Who are the best candidates for the procedure?

The procedure takes about three hours and the patient usually stays in the hospital for a day or two.

Dr. Oviedo says fewer than 5% of patients treated with the TAR have a recurrence, a huge improvement over those treated with open surgery.

Dr. Oviedo stresses that TAR is most suited for high-risk patients, such as the morbidly obese. Historically, such patients were told to lose 50 pounds to reduce the risk of recurrence, a goal many never reached, often because they wound up in the ER with a strangulated bowel before they could lose the weight. This predicament led to the development of the new technique.

Other risk factors include:

• diabetes, whose accompanying microvascular problems and effect on the blood supply interferes with the healing of the abdominal wall
• rectus diastasis, a usually congenital but sometimes acquired issue involving the separation of the six-pack muscle
• connective tissue diseases
• previous hernia repair by open surgery

TAR has been around for five years now, but is likely only performed in fewer than 10% of centers, most of those academic. Houston Methodist did its first TAR procedure earlier this year, and has performed five more since.

"I think these robot-assisted laparoscopic hernia repair surgeries are the future," says Dr. Oviedo. "But for now, it takes expert surgeons and centers to do it."