Gelatin Arterial Injection in Human Brain as Method for Enhanced Visualization for White Fiber Dissection for Neurosurgical Skills

Abstract

Background

In the evolving landscape of neurosurgery, the knowledge of three-dimensional neurovascular anatomy is a key step in the undergraduate and postgraduate medical education. Gelatin-injected brain models can become a cornerstone in neurosurgical training by providing a real experience that could improve surgical skills and results. This article presents an original technique to label the vascularization using arterial injection in human brains.

Materials and Methods

The procedure is performed on formalin-fixed donated cadavers, and gelatin aqueous solutions colored with dry pigment are injected into the internal carotid arteries after flushing with normal saline.

Results

With the help of this technique, the vascular system of the brain is well perfused and gelatin-injected vessels maintain real appearance as well as aid in better perfusion of small vessels for white fiber dissection.

Conclusion

In this article, we described the method and step-by-step guidelines to inject the colored material along with aqueous gelatin by intra-arterial injection to visualize the cerebral vasculature. This creates an enhanced model for white fiber dissection for neurosurgical training.

Keywords

brain arterial vessels - brain specimen - Klingler technique - white fiber dissection - white matter anatomy

Introduction

The three-dimensional knowledge of neuroanatomy is a key step in neurosurgical fields, where the use of corpses is a great source to develop knowledge, being crucial in guiding surgical approaches. In neurosurgical practice, the knowledge of vascular system and its muscle, bony, meningeal, cisternal, and ventricular relationships relevant to neurosurgical approaches are essential.[1] The experience of guiding the approaches before the actual surgical procedures is vital to augment the clinical competences of surgeons.[2] [3] In previous studies many authors such as Humphrey Ridley, Thomas Willis, and Richard Lower used arterial injections.[4] Leonardo da Vinci made injections to administer via arterial system and made molds from the cerebral ventricles.[5] Historically, many materials such as mercury, spermaceti, tallow, latex, epoxy resins, and silicone have been used as an injecting material into the cerebral vascular system.[4] [6] But current literature lacks a complete and comprehensive knowledge of the vascular territories. Hence, this article presents an original method to mark the vascular supply of white matter fasciculi macroscopically based on the basic protocol of arterial injection of colored material with aqueous gelatin.

Steps for vessel catheterization:

1. Fixed cadaver embalmed with 10% of formalin must be placed in supine position.

2. Identify the anatomical landmarks using dissector, follow the dissection steps, and identify the internal carotid artery.

3. After the careful dissection of internal carotid artery, use silicone catheters (5 French) for selective catheterization of internal carotid artery. Concomitantly, the other side, internal carotid artery, must be securely closed.

4. Vessel is ligated around the inserted catheters and the catheter–vessel interface is then secured with cyanoacrylate glue.

5. After this, the arterial system is washed thoroughly using a saline solution as a fundamental step to remove any remaining blood and clots. Flush the catheterized artery continuously with 200 mL of isotonic saline using a 50-mL syringe.

6. Pressure must be adequate as excessive pressure could lead to damage of small vessels, which are vulnerable to damage.

7. During the saline washing, special attention is required to identify and rectify any leakage sites. Closure of leakage sites is attained by using black silk or using arterial clips or with the help of glue.

Preparation of injection material:

1. Dry pigment (red color for arteries) is diluted in distilled water having pigment concentration of 0.5% followed by heating the mixture to 32°C.

2. Allow the mixture to transfer it to the syringe, care must be taken to transfer it early as to prevent the gelatin from early solidification.

Injection of material:

1. Inject the colored gelatin into internal carotid artery continuously till the filling of arterial system is satisfactory ([Figs. 1] and [2]).

2. Care must be taken to avoid overflowing of material.

3. Continue the same procedure on the contralateral side.

4. After 24 hours, extract the brain carefully to avoid injury to the cerebral vascular system; do not use traction during exposition of structures followed by photographic documentation ([Fig. 3]).

5. Brain will be immersed in a 4% buffered formaldehyde solution for 2 months at ambient temperature. To achieve this, brain will be suspended by using a thread around the basilar artery to prevent the distortion provoked by contact with the walls of the container.

Fig. 1 Showing the contents in the carotid triangle in the neck, highlighting the internal jugular vein, bifurcation of carotid artery, internal carotid artery, and vagus nerve.

Fig. 2 Arterial gelatin injection is administered through the internal carotid artery using a catheter inserted via the carotid triangle in the neck, highlighting the internal jugular vein and internal carotid artery.

Fig. 3 Postinjection view after opening the skull vault shows the pial arteries.

Discussion

There are various materials used for arterial injection in the literature depending on either requirements or objectives. Even though the knowledge of vascularization of white matter is necessary in understanding the pathophysiology after a stroke, traumatic brain injury, or postsurgical ischemia, but it is quite abandoned in the literature. The use of injecting materials via the vascular system for anatomical investigations and teaching purposes was started after William Harvey developed the blood circulation doctrine.[7] To develop this technique, Cole made great research in the history of anatomical injections.[5] J. Swammerdam injected solidifying materials for the first time as an anatomist; on the other hand, Sir Charles Bell injected mercury in lymphatic vessels.[5] [8] As mercury do not change its state of matter but some materials like resins or silicone get solidified by the phenomenon of polymerization, barium and iodine can be injected in vessels as they are radiopaque.[9]

Gelatin is a dissection-compatible material, eco-friendly, reasonably priced, and can be colored with different water-soluble dyes. Gelatin is organic in nature and its gentleness makes it suitable for consequent dissection. There are various other injection materials that were proposed but did not comply with further white fiber dissection.[10] [11] [12] [13] [14] [15] [16] [17] [18] [19]

In this article, we explained and demonstrated the technique for preparation of injection material and the method of injection for further white fiber dissection. This protocol is essential for a defined and detailed description of brain vascular anatomy, specifically as a scaffold for the detailed vascularization of white fiber tracts. The methodology used is flexible and due to the great properties of the gelatin, the brain specimens prepared can be dissected with ease and in addition to this, these specimens can be sectioned serially for histology. It would help in accomplishing the relevant information to better understand the further consequences of occlusion of vessels in clinical aspect as well as the data is essential for validation of various radioimaging techniques[20] and its involvement in the further models could aid in decoding the microarchitecture of the brain.[21]

Conflict of Interest

None declared.

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Publication History

Article published online:
13 June 2025