The Feasibility Of Digitalized Skullbase Surgery:Anatomical And Medical Imageology Studies

Background:Skull base or cranial base surgery has been developed into as a multidisciplinary subspecialty since late1980s because of the complex anatomical features in these regions incorporating many very important, even vital structures, which requires extensive knowledge of the related anatomy from the neurosurgeon to ensure accurate intraoperative orientation and minimize the risk iatrogenic injury.Conventional data for neurosurgery from statistically analyzed parameters achieved by manually measured with scientific callipers in series of anatomy specimen, lacking individualized information of the patients, have limited value for ideal intraoperative orientation, whereas the accuracy of individually-based image-guided surgeries was usually compromised by inevitable intraoperative brain shifting. Such problem of soft tissue shifting can be overcome by using immobile bony structures as landmarks for intraoperative orientation during skull base surgeryies. Image-guided surgery systems are therefore, ideal for skull base surgery.The present study evaluated the accuracy of computed tomography (CT) imageolo gy and image-guided surgery measurements of the skull base compared with anatomical measurements using scientific callipers.Objective:To quantatively evaluated the feasibility of digitalized skullbase surgery by comparing the corresponding accuracy of anatomical, imageology and neuronavigator based measurements.Methods:The Certain anantomical parameters from twenty-five cadaver skull bases(50sides)were measured with caliper(anatomical measurement), CT (imageology base measurement) and neuronavigator (neuronavigator based measurement),respectively. The data were documented and the accuracy of three different methods of measurement was analyzed statistically with Spss19.0software.Results:1)No methodological difference is statistically (P>0.1) indicated amongst imageology based, neuronavigator based and anatomical measurements;2) The Coefficient of Variance achieved from imageology based measurement is smaller than that from anatomical measurement in most of the parameters, which indicated a more stable result from the former, whereas the potential reason that made the Coefficient of Variance from imageology based measurement larger for the distance between the lateral semicircular canal and oval foramen may result from its complex anatomical features that makes challenge to the knowledge of anatomy as well as the objectivity of the judgment from the operators;3)The mean deviation of both the anatomical and the neuronavigator based measurement were larger than that of mean deviation of the imageology based measurement from the corresponding mean of anatomical measurement (P<0.01);4) The mean deviation of the neuronavigator based measurement from the mean of anatomical measurement were a little bit larger than that of anatomical measurement, whereas the P value (90%) was larger than0.8.Conclusions:1) There is no real methodological difference amongst imageology based, neuronavigator based and anatomical measurements;2)The data from imageology based measurement are more accurate than those from group-based anatomical measurement in evaluating individual anatomical characteristics;3) Statistically equivalent accuracy is undeniable (The power of the test was as high as90%) between the anatomical and neuronavigator based measurements, even if deviations from the latter are inevitable;4)The accuracy of both imageology and neuronavigator based measurement for complex anatomical structures make challenges to the knowledge of anatomy from the operators.