ENT surgery: minimally invasive and robot-assisted procedures

The ear, nose and throat are full of tiny structures, and each plays an important role in the health of a person. The inside of the ears makes it possible for us to hear, while the inside of our nose enables us to smell. The larynx contains the vocal cords, which allow us to speak and stay connected to the outside world. It is crucial that the function of these organs must not be accidentally damaged during surgery.

Surgical interventions in these areas are complex and must be performed with the utmost precision and ability. Any injuries during the procedure can lead to severe consequences for the patient's health. It only stands to reason that more and more minimally invasive surgery procedures are becoming the preferred treatment option thanks to advances in technology.

A great example of this is cochlear implant surgery. "Conventional cochlear implant surgery requires surgeons to create a large opening in the mastoid bone (the part of your skull located behind your ear) to get a better view and gain access to the cochlea," explains Prof. Wolfgang Gstöttner from the Medical University of Vienna in a MEDICA-tradefair.com interview. The electrode array of the implant is inserted into the cochlea through this opening. This leaves a cavity in the bone, which can only be partially closed and covered.

The HEARO implant surgical robot by CAScination can reduce trauma for the patient in this setting. "It drills a 1.8 mm wide access channel and removes as little bone as possible," explains Gstöttner. The channel is wide enough to insert the electrodes safely. However, surgeons must still proceed with the utmost caution to prevent and reduce risk to the patient as the channel must be milled and passed at a very close distance from the facial nerve to reach the cochlea. Injury to the facial nerve can cause facial paralysis. To prevent this, safety measures include continuous neuromonitoring during the drilling process, which tracks the drill’s proximity to the nerve. This ensures a maximum level of safety during this complex microsurgical procedure.

While the larynx is somewhat easier to access than the inner ear, it is no less sensitive. Nerves in this area are susceptible to injury following a variety of interventions such as thyroid surgery, cervical spine or thoracic surgery. As a result, impulses from the brain are no longer transmitted to the vocal folds. They lose muscle tension, which subsequently means the vocal folds can no longer be properly tightened and moved. This prompts vocal fold paralysis, affecting either one or both vocal folds. In a MEDICA-tradefair.com interview, Prof. Andreas Müller from the SRH Wald-Klinikum Gera explains the consequences: "In the case of unilateral vocal fold paralysis, the dominant effect is a voice disorder, meaning the voice sounds hoarse and weak. In bilateral vocal fold paralysis, breathing becomes difficult because the vocal folds cannot open."

There are two approaches to the surgical treatment of this condition: the first one is called reinnervation where nerves in the throat are moved toward the larynx. The impulses transmitted by these nerves cause the muscle tension of the vocal folds to increase. With more complex options of this procedure, this process even partially restores the normal mobility of the vocal folds - and thus the functionality of the larynx.

The implantation of a laryngeal pacemaker system pursues a similar goal. This approach resembles the workings of a heart pacemaker. The device consists of a pulse generator that is implanted in the chest area and two electrodes that are positioned from there to the larynx. The implantation process is minimally invasive to avoid subsequent damage to and around the larynx. The electrodes can bridge the damage to the nerve, which interrupts the connection between the brain and muscle: "However, since there is still a neuromuscular connection, the laryngeal pacemaker system aims to stimulate the target muscle directly behind the site of the nerve injury. This triggers the vocal folds to open," explains Müller, who is involved in approval studies for the laryngeal pacemaker system.

These two examples show that minimally invasive procedures are becoming increasingly important in ENT surgery. As in many other surgical specialties, robotic systems are poised for continued growth and advancement in the future. Prof. Gstöttner agrees and anticipates additional applications for HEARO. He knows the device can accomplish more than just assist common types of surgeries: "Our goal is to use the robot for procedures that we can no longer perform with the same accuracy and precision. After all, cochlear implantations go along with a variety of complicated situations. We are presently looking for solutions to problems that only a robot can solve." That means, HEARO does more than just extend a surgeon’s capabilities in the operating room. Since it can move autonomously – though still under human supervision and monitored by safety mechanisms–, it can accomplish more than previous surgical robots.