engleski

Evaluation of the neurosurgical endoscopic contact ultrasonic probe

The aim of our study has been to evaluate construction of an neurosurgical endoscopic contact ultrasonic probe (NECUP) with respect to some specific technical, medicinal and operational requirements. On the basis of the theoretical model, the NECUP has been realized as a rod-type resonant vibrating system, consisting of a half-wave length transducer of piezoceramic material, and a resonant wave guide in the form of a specially shaped velocity transformer with titanium wire. Special attention has been paid to the electro-acoustical characteristics (high efficiency of the transducer, low losses in the wave-guide, stability of the longitudinal vibrations at high amplitudes) of the transducer as well as of the wave guide. Due to the principle of ultrasonic surgery (direct cutting, cavitation, fragmentation and thermal damage), the irreversible changes in brain tissues are reported. Light and electron microscope assessed the lesion made in the brains of experimental rats. Histological findings showed the zone of the thermal injuries (100-200) &#61549 ; m and the zone of ultrastructural changes from (200-300) &#61549 ; m, indicating the sparing effect of the probe with regard to the adjacent neurovascular structures. Authors present clinical application of the NECUP in endoscopic third ventriculostomy (ETV) procedures. Surgery was performed in patients with neurological symptoms of elevated intracranial pressure and neuroradiological evidence of non-communicating hydrocephalus caused by mesencephalic aqueduct stenosis. The newly designed NECUP is 1, 6 mm in diameter and easily passes through the 2, 2 mm ventriculoscope working channel. It is a new and effective tool in neurosurgical armamentarium as it enables safe fenestration of the third brain ventricle at minimal thermal and ultrastructural damage of the adjacent neural structures with maximal preservation of vascular structures. Further research will be focused on defining possibilities for the use of the device in other endoscopic procedures as well.

ultrasonic energy; lesion; tranducer; surgery; minimally invasive procedures

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