Intraoperative Spinal Cord Remote Monitoring with a Modified US A-Scope

Abstract

Materials and Methods: The motivation for this feasibility study were: (i) to modify the ultrasonic A-scope in order to monitor remotely, intraoperatively and in real-time tumor’s depth and size, before cutting its dura and to control tumor’s residual thickness while its resection and (ii) to demonstrate these abilities during several spinal-cord surgeries. Results: The ultrasonic A-scope was modified for these purposes, to a noncontact, intraoperative and real-time device. It was successfully applied during several human spinal cord clinical trials. Its data were compared with those of a pre-operative MRI (of the same person), where a good similarity was obtained between them, with a difference less than 1mm, in most cases. Conclusions: The modified A-Scope advantages: (i) remote, intraoperative and real-time monitoring; (ii) accurate and objective data was obtained; (iii) there is no direct contact between the US transducer and the monitored tissue, as the ultrasound propagates through a free stream of normal saline; (iv) the length of the free stream is few mm, at least; (v) the handpiece enables to monitor in a confined area, as it has a small foot-print; (vi) it is simple to operate the device; (vii) it enables to define intraoperatively tumor edges, before cutting and opening the dura. Consequently, this modified device seems to be a valuable and useful tool to define intraoperatively tumor’s location and its complete removal and reducing potential damages to healthy tissues surrounding it.