What is the Neuropathological Autopsy Technique?

26 June, 2020
A neuropathological autopsy technique involves two major phases. The first is a cranial autopsy and the second is an spinal autospy. In the first, doctors remove the brain, and in the second, the spinal cord, in order to conduct their investigation.

Primary injuries are those that correspond to a fundamental process or one that leads directly to death. Injuries of a secondary nature, on the other hand, are those that play a role in another fundamental pathology present in the body.

The neuropathological autopsy technique involves processes of extraction and sampling of the nervous system. These are regulated procedures and vary regarding quantity and location, depending on whether the injuries are primary or secondary.

The macroscopic neuropathological autopsy technique involves two major phases: a cranial autopsy and a spinal autopsy. In the cranial autopsy, doctors extract and study the brain. Likewise, in the spinal autopsy, they extract the spinal cord, roots, and posterior lymph nodes.

We’ll take a closer look at this interesting procedure in this article.

The steps involved in the neuropathological autopsy technique

A brain autopsy.
The extraction and subsequent analysis should take place as soon as possible, ideally within the first 24 hours after death.

Ideally, the extraction of the brain should take place within 24 hours of the individual’s death. In general, those who perform the procedure are a pathologist, a technician, and an assistant. The steps to follow in the extraction of the brain are the following:

The extraction of the brain

  • The experts place the cadaver on the autopsy table in the supine position. A headrest should support the neck and occipital to elevate the cranium and facilitate handling.
  • After, professionals use a surgical knife to create an incision from one pinna to the other. The depth should reach the periosteum or, in other words, nearly to the bone.
  • Then, they separate the periosteal cutaneous flaps, pulling them away from the incision and outward. In doing so, they expose the cranium.
  • The next step involves cutting using a circular saw.  The cut begins at the front part of the cranium and then turns all the way around until reaching the starting point. This cut should not surpass the dura mater.
  • Next comes the opening of the upper longitudinal sinus from front to back. Then, the professionals remove a small part of the dura mater and cut laterally. As a result, the brain remains exposed.
  • What follows is the separation of the frontal poles. They often do this with the index fingers, tugging gently. After this, the doctors proceed to cut the optic chiasm and the remaining parts of the cranial nerves. The brain is now free.
  • Then follows the cutting of the two sides of the cerebellar tentorium, or tentorium cerebelli, with a scalpel.
  • One of the professionals then removes the brain, cerebellum, and the brainstem and then cut the medulla oblongata. This cut is very low to obtain a complete sample of this structure. The brain is then completely free.
  • Finally, the professionals break through the anterior clinoid process with a chisel. After this, they widen the sella turcica with their hands and extract the pituitary gland with a scalpel and a clamp.

Discover more: What is Neuroplasticity in the Brain?

The handling of the brain in the neuropathological autopsy technique

A model of the brain.
After its extraction, professionals should wash the brain and conserve it properly in formeldahyde.

After the brain’s extraction, it’s time to weigh it on a scale and then hang on a string that goes from the basilar to the brainstem. Finally, they leave the brain floating in 10% formaldehyde.

They then must close the container hermetically and label it. Normally, the brain will remain in formaldehyde for two weeks, except in cases of suspected prion disease. If that’s the case, then this period will extend to one month at the very least.

Once this period is over, then the external macroscopic study will take place. The first step is to wash the brain in water for 24 hours. Then palpation and inspection should take place. The next step is to perform the coronal cuts and the taking of samples for the subsequent microscopic study.

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The spinal autopsy

The other major part of the neuropathological autopsy technique is spinal autopsy. The first step here is to extract the spinal canal, using an internal and external approach. Once free, the professional prepare it for the subsequent palpation and inspection of both sides.

The sampling of the spinal canal follows next. This involves making transversal cuts each three to four centimeters. In the case of a specific spinal pathology, representative samples of the lesion will be necessary. The samples must come from the cervical, dorsal, and lumbar regions, as well as from the sacrum level, when possible.

Overall, these are just a few of the amazing processes experts can resort to to learn about the cause of death and improve future medical treatments.

  • De Guevara, J. F. L. Técnica de la autopsia neuropatológica Técnica macroscópica de realización de la autopsia y procedimiento de obtención de muestras.