Application of a pressure sensor chip for intraoperative micro movement detector

The authors describe a newly designed movement detector which is useful for numerous microneurosurgical procedures. Muscle contraction evoked by the stimulation is detected by a small disc-shaped pressure sensor taped to the overlying skin. The responses are monitored both quantitatively on a liquid crystal display and qualitatively through an on-off auditory signal. This detector is characterized by low impedance and high-sensitivity, by which it can be insulated from electrical noise. This detector can safely and reliably monitor the facial nerve, nerves involved in eye movements, lower cranial nerves and spinal nerves. This movement detector weighs only 3.2 g and has the diameter of 10.4 mm, and can easily be used by a neurosurgeon.