Modified Head Fixation System for Intraoperative —
Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Nagano; *Department of Neurosurgery, Nagoya University School of Medicine, Nagoya
Abstract A head
Key words: stereotactic
Introduction The head fixation system is an important instrument in neurosurgery, especially in open-field neuro surgery.10) Many systems have been designed and used for safe, precise surgical procedures. i,2,s,6.s,9) Recently, intraoperative radiological diagnostic methods such as digital subtraction angiography and computed tomographic (CT) scanning have been in troduced into the operating theater .3,4,7)This requires improvement of the head fixation system to reduce imaging artifacts by using radiolucent materials. We use the CT scanner in our operating room,' and so have modified the ordinary head fixation system for intraoperative CT scanning. Modified
The head fixation system (head holder and pins9') was modified using an L-shaped head pin in a sup porting device on the head holder (Fig. 1). The reinforced carbon fiber head pin can be extended above the head holder and allows CT scanning with out artifacts (Fig. 2). The modified head fixation system allowed artifact-free CT images when used with the dry skull (Fig. 3 left), and in clinical intra Received
Schematic drawings of the modified head fixation system. L-shaped head pin made of carbon fiber (a) and pin supporting device (b).
of the head pin, CT images using
successfully the ordinary
produced artifact-free head holder.
Fig. 3 CT images with no artifacts using the modified head fixation system with dry skull (left) and in a clinical trial (right). 9)
operative CT scanning during removal of recurrent astrocytoma (Fig. 3 right). Discussion Our system was developed exclusively for intra operative CT scanning. Engle et al.3' developed a rigid ceramic head fixation device for intraoperative CT. However, their fixation system is too large for use with ordinary surgical instruments. Our modified fixation system, by changing the material and shape
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Address reprint requests to: H. Okudera, M.D., Depart ment of Neurosurgery, Shinshu University School of Medicine, Japan.