Intraoperative computed tomography guided neuronavigation: Concepts, efficiency, and work flow

Abstract

Image-guided surgery is currently considered to be of undisputed value in microsurgical and endoscopical neurosurgery, but one of its major drawbacks is the degradation of accuracy during frameless stereotactic neuronavigation due to brain and/or lesion shift. A computed tomography (CT) scanner system (Philips Tomoscan M) developed for the operating room was connected to a pointer device navigation system for image-guided surgery (Philips EasyGuide system) in order to provide an integrated solution to this problem, and the advantages of this combination were evaluated in 20 cases (15 microsurgical and 5 endoscopic). The integration of the scanner into the operating room setup was successful in all procedures. The patients were positioned on a specially developed scanner table, which permitted movement to a scanning position then back to the operating position at any time during surgery. Contrast-enhanced preoperative CCTs performed following positioning and draping were of high quality in all cases, because a radiolucent head fixation technique was used. The accuracy achieved with this combination was significantly better (1.6:1.22.2). The overall concept is one of working in a closed system where everything is done in the same room, and the efficiency of this is clearly proven in different ways. The most important fact is the time saved in the overall treatment process (about 55 h for one operating room over a 6-month period). The combination of an intraoperative CCT scanner with the pointer device neuronavigation system permits not only the intraoperative control of resection of brain tumors, but also (in about 20% of cases) the identification of otherwise invisible residual tumor tissue by intraoperative update of the neuronavigation data set. Additionally, an image update solves the problem of intraoperative brain and/or tumor shifts during image-guided resection. Having the option of making an intraoperative quality check at any time leads to significantly increased efficiency, improves the operating work flow because of the closed-system concept, and offers an integrated solution for improved patient work flow and clinical outcome.

Intraoperative ultrasound assistance in treatment of intradural spinal tumours

“…16 Over the last few years, intraoperative imaging aids such as MRI and CT have been considered for neurological surgery. [17][18][19][20] In spite of higher resolution, these costly technologies require cumbersome procedures, are rigid and difficult to adopt for continuous real-time imaging during surgery. In comparison, IOUS is of low cost and flexible, different ultrasound probes can be applied relatively easily to adapt to various sizes and shapes to address various applications in surgery.…”

Neuronavigation: geneology, reality, and prospects

“…In 1998, Matula et al 61 connected a fixed iCT scanner (Philips Tomoscan M) to a LED-based navigation system (Philips EasyGuide system) to provide an integrated solution to the problem of brain shift. The gantry was fixed and the patients were positioned on a specially developed scanner table that permitted movement from a scanning position to the operating position at any time during surgery.…”

Low-field magnetic resonance imaging for intraoperative use in neurosurgery: a 5-year experience

“…Intraoperative CT, either with fixed systems, as originally introduced [7,8,9,48], or on tracks [6], or the recently presented system of mobile CT [4,5,49], does not require special instruments; however, low soft tissue contrast, as well as missing free slice orientation and the need for X-ray protection requirements, are major drawbacks compared with intraoperative MR imaging. Intraoperative CT has its advantages in the evaluation of bony structures, making it highly suitable for imaging in spine surgery [50].…”