Ultrasound-Oriented Surgical Planning ('UOSP') for Intracranial Lesions: A Systematic Integration to the Standard Preoperative Planning

Objective: Intraoperative ultrasound (iUS) is a well-established technique whose aim is to provide real-time visualization of deep lesions during brain surgery. The lack of definition of anatomic semeiotics and the unusual direction of the insonation plane make interpretation and orientation challenging for the surgeon who newly approaches to such a tool. We propose a novel protocol to be applied during the surgical planning for intracranial lesions surgery, a so-called ultrasound-oriented surgical planning ("UOSP") protocol, and we provide a retrospective analysis of 21 patients who underwent surgery for an intracranial lesion in which UOSP was applied. To further enlighten different surgical orientation strategies and possible limitations given by the technique, we discuss 3 illustrative cases assigned to 3 categories ("basic," "intermediate," and "challenging" lesions) with progressively growing difficulty in anatomic orientation during a surgical procedure. Methods: A total of 21 patients operated between March 2021 and July 2021 and where the UOSP protocol was applied during surgical planning were evaluated retrospectively. The UOSP protocol was performed the days before the surgical intervention by the same surgical team. Results: The UOSP protocol was successfully applied in all 21 patients. In all cases, the preoperative imaging obtained during surgical planning corresponded to the images observed during the application of iUS. Conclusions: The introduction of the UOSP protocol during the planification of the surgical intervention for an intracerebral lesion may serve as a key factor to overcome the actual limitations inherent to the iUS technique. Utilization of this protocol may facilitate wider use of iUS in neurosurgery.