Hermann Elvis J, Petrakakis Ioannis, Polemikos Manolis, Raab Peter, Cinibulak Zafer, Nakamura Makoto, Krauss Joachim K
Department of Neurosurgery, Medical School Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany,
Acta Neurochir (Wien). 2015 Jul;157(7):1229-37. doi: 10.1007/s00701-015-2452-2. Epub 2015 May 21.
Electromagnetic (EM)-guided neuronavigation is an innovative technique and a viable alternative to opto-electric navigation. We have performed a safety and feasibility study using EM-guided neuronavigation for posterior fossa surgery in the semi-sitting position in a selected subset of patients.
Out of 284 patients with posterior fossa tumours operated upon over a period of 40 months, a subset of 15 patients was thought to possibly benefit from EM navigational guidance and was included in this study. There were six children and nine adults (aged between 8 and 84 years; mean age, 34.6 years) with different neoplasms in the brainstem or close to the midline. All patients had contrast-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) of the head preoperatively. EM-guided navigation was used to identify and preserve the venous sinuses during craniotomy and to determine the trajectory to the lesion using various approaches. Neuronavigation accuracy was repeatedly checked for deviations measured in millimetres on screen shots during surgery before and after dural opening in the coronal (z = vertical), axial (x = mediolateral) and sagittal (y = anteroposterior) plane.
Referencing of the patient in the supine position was fast and easy. There was no loss of navigation accuracy after repositioning of the patient in the semi-sitting position (mean, 2.5 mm ± 0.92 mm). Identification of the pathological structure using EM navigation was achieved in all instances. Optimal angulation of the neck was selected individually to permit a comfortable position for the surgeon with full access to the lesion avoiding over-flexion. Deviation of accuracy at the surface of the target lesion ranged between 2.5 and 5.8 mm (mean, 3.9 mm ± 1.1 mm).
EM-guided neuronavigation in the semi-sitting position was safe and technically feasible. It enabled fast and accurate referencing without loss of navigation accuracy despite repositioning of the patient. In contrast to conventional opto-electric neuronavigation there were no line of sight problems.
电磁（EM）引导神经导航是一种创新技术，是光电导航的可行替代方案。我们对部分选定患者在半坐位下行后颅窝手术时使用EM引导神经导航进行了安全性和可行性研究。
在40个月期间接受后颅窝肿瘤手术的284例患者中，有15例患者被认为可能从EM导航引导中获益并纳入本研究。其中有6名儿童和9名成人（年龄在8至84岁之间；平均年龄34.6岁），肿瘤位于脑干或靠近中线，类型各异。所有患者术前均进行了头部对比增强三维（3D）磁共振成像（MRI）检查。在开颅手术过程中，使用EM引导导航识别并保留静脉窦，并采用各种入路确定到达病变的轨迹。在硬脑膜打开前后，在冠状面（z =垂直）、轴位（x =中外侧）和矢状面（y =前后）平面上，通过手术期间屏幕截图上以毫米为单位测量的偏差，反复检查神经导航的准确性。
患者仰卧位时的参考定位快速且容易。患者重新定位至半坐位后，导航准确性没有损失（平均2.5毫米±0.92毫米）。在所有情况下均通过EM导航实现了对病理结构的识别。根据个体情况选择最佳的颈部角度，以便外科医生处于舒适的位置，能够充分暴露病变，避免过度屈曲。目标病变表面的准确性偏差在2.5至5.8毫米之间（平均3.9毫米±1.1毫米）。
半坐位下的EM引导神经导航是安全的，技术上可行。尽管患者重新定位，但它能够实现快速准确的参考定位，且不损失导航准确性。与传统的光电神经导航相比，不存在视线问题。
