197 - Prevention of Facial Nerve Injury in Mastoidectomies through EMG

Description: Even with detailed knowledge of anatomy and surgical agility in ear surgery, nerves can sometimes be difficult to identify due to pathologies, previous surgeries, or normal anatomical variations that occur from person to person.

Patients may suffer temporary or permanent damage if a nerve is irritated or injured during surgery, which is a constant concern for surgeons. Mastoidectomy raises concerns about facial nerve injuries, which can occur iatrogenically.
Sometimes, a slight irritation or stretching of the facial nerve can lead to temporary or permanent symptoms of nerve damage, such as facial weakness, numbness, or spasms. Extrusion of the facial nerve, although rare, causes facial paralysis, which resembles the morbidity seen in a stroke.

The Medtronic NIM™ systems, currently used at Pedro Hispano Hospital in Matosinhos, help surgeons locate and identify the nerve, monitor and control the effects of manipulation on the nerve, and confirm its integrity before concluding the surgery.
The intraoperative neuromonitoring system NIM™ is an electromyographic (EMG) monitor for use during various surgeries where a nerve may be at risk due to unintentional manipulation. NIM™ nerve monitoring electrodes are placed in the appropriate muscle locations of the patient for the procedure being performed.

These electrodes are connected to the NIM™ systems, which monitor the EMG activity of the muscles innervated by the affected nerve. When a specific nerve is activated or stimulated, the NIM™ system alerts the surgeon and the operating room team, providing visual alerts on the color touchscreen monitor and audio feedback to help minimize nerve trauma.

Since 2024, the use of NIM™ has increased in the ENT specialty for mastoidectomy surgeries, resulting in almost zero iatrogenic facial nerve injuries.
The trend in 2025 is for its use to continue growing in our hospital, and so far this year, no injuries have been reported, which concludes that the association of technology with current surgical techniques has brought advantages and excellent results to our patients.