核医学と放射線治療

Safety of Microstimulator During Radiation Therapy - A Preliminary Study on Head and Neck Cancer Patients

Abstract

Uttam K. Sinha, Brenda Villegas, C. Kuo, Frances J. Richmond, Rizwan Masood, Nora I. Nelson and Gerald E. Loeb

Objectives: To determine the safety and performance of miniature neuromuscular stimulator called MicroStimulator (MS) during radiation therapy (RT) of head and neck cancer (HNC).
Study Design: Pilot study
Methods: Four patients who underwent modified radical neck dissection for HNC received MS implants. The implant was placed 2-3 mm above and parallel to the hypoglossal nerve. All patients had tracheotomy and gastric tubes placed during surgery. Stimulation thresholds were obtained in three patients and electrical exercise programs were initiated in two patients. One patient completed the study, started RT and stimulation of the MS 3-4 weeks after surgery. The implant was energized and controlled by a radio frequency magnetic field from an external coil placed near the implant. Patients underwent stimulation of the MS one hour per day using intermittent trains of stimuli generating fused, maximal contractions.
Results: No postoperative or implant specific complication was noted. All patients required and tolerated stimulation without pain or discomfort. Visible contraction of muscles of swallowing was noted in both patients during stimulation indicating that MS remained functional during RT. All patients used the device at home and maintained their oral feeding and weight. None had aspiration pneumonia.
Conclusions: MS appears to be a safe device for stimulation of swallowing muscles during MS for HNC. Implant performance is not affected by RT. It effectively stimulates the nerves to induce robust contraction of muscles of swallowing and laryngeal elevation. High patient compliance was achieved with this implant.