This chapter will introduce you into tissue handling at an already quite sophisticated level. However, if you understand the principle of this technique already at an early stage of your training, you will be more capable of understanding the surgery in which you will only assist during your first years. In this chapter, you will learn how to remove a gyrus, a technique essential in resection of infiltrating tumors. At the same time, you will learn some important anatomical lessons.
Relevance for your daily practice
The understanding of this resection technique is of utmost importance for high-level brain tumor surgery.
The objective of this chapter is to give you a basic understanding of the principles of brain tissue removal.
Imagine the following scenario: imagine that you plan to resect a low-grade glioma, which for the major part (according to magnetic resonance imaging) is superficially located in a gyrus (Fig. 4.1). Due to the biology of the tumor, you need to assume that large parts of the gyrus are infiltrated by tumor cells. You have tested the functionality of the gyrus by neuromonitoring.1-3 According to your findings, the tumor harboring gyrus can be removed. Your task is now to remove this gyrus without damaging the adjacent gyri, in which (unfortunately) you have located the motor functions. Please review and understand the anatomy of this situation by studying the illustration (Fig. 4.2). Note the pial layer which cover the surface of the brain. You will have to cut through this layer using a scissor or knife. This layer offers protection for the underlying structures and therefore also for the vessel running in the sulcus (Fig. 4.2) and the adjacent brain. If you manage to remove the brain without perforating the pia, these structures are relatively safe. This surgical technique is called subpial resection. Apart from safety issues, this technique implies (in the area of subpial coverage) a complete biological resection of the tumor (no brain, no tumor). Please realize that as soon you enter the white matter at the bottom of the gyrus, the situation changes: you might enter functional fiber tracts, so your resection technique needs to change. Let us, however, focus on the subpial resection for the moment.