Dear Editor,

The neurosurgical training of residents and neurosurgery specialists in our country, and the rest of the world, is through dissection in cadavers fixed with formaldehyde, and human brains preserved with the Klingler technique, a technique that in recent years has become a fundamental tool in neurosurgical teaching. In the same way, this technique allows dissection, investigation, and exposure of white matter fibers; such as association fibers, projection fibers, and commissural fibers belonging to the corpus callosum and other commissures. The Klingler technique was created by the German neuroanatomist Joseph Klingler in 1935 as a unique method for the preservation and dissection of white matter fibers, nuclei, and brain stem¹. This method consists of 5 stages. Obtaining human brains without alterations in the parenchyma and, with a post-mortem between 24 and 48 h; fixation with 10% formaldehyde for a minimum period of 60 days; dissection of arachnoids and vascular elements with the help of forceps and microdissection scissors; the freezing process for 10 days at a temperature between 15 and 18 degrees; and finally the thawing process for 24 h at room temperature²,³ (Fig. 1). About 10% formaldehyde perfectly penetrates the gray matter, which when frozen forms microcrystals that separate both substances, allowing easy dissection using a wooden spatula²-⁴. On the other hand, the dissection of white matter fibers using the Klingler technique is not a new technique, its study and understanding are still extremely useful since it gives us the possibility of better understanding and manipulating the internal configuration of the brain, obtaining better neurosurgical training.

Figure 1 A: ventral side of the brain, previously fixed with 10% formaldehyde and frozen. B: dorsal side of the brain, left hemisphere decorticated and exposing white matter fibers of short association. C: lateral view of the brain, exposing the lobe of the insula (yellow star). D: dissection of the lateral aspect of the brain, exposing the uncinate fasciculus (yellow arrow). 

Without forgetting that to achieve optimal results, a minimum of three fundamentals are needed: (1) possess extensive knowledge of neuroanatomy, (2) possess excellent training and manual dexterity, and (3) patience and perseverance¹.