Evaluation of cellular reaction in brain tissue against platinum coil usage in the treatment of intracranial aneurysm

Hemorrhages in the subarachnoid space (between the subarachnoid membrane and the pia mater), for any reason, are referred as subarachnoid hemorrhage (SAH). Although bleeding arise from a certain point; blood diffuses into the supratentorial, infratentorial and spinal subarachnoid space via the cerebrospinal fluid (CSF). In other words, SAH is a pathological condition that does not only involve a specific area of the central nervous system, but the whole. SAH causes 25% of cerebrovascular deaths. Despite the advances in diagnosis and treatment in recent years, SAH continues to be a serious health problem due to its high mortality and morbidity. In general, it is accepted that an average of 10/100000 non traumatic SAH is seen in the society annually. It has been shown that the cause is aneurysm bleeding in approximately 75-90% of patients. Although SAH can be seen at any age, it frequently occurs between the ages of 50-65. The most serious complication of aneurysmal SAH is the second bleeding. While the mortality after the first hemorrhage is 30%, the mortality after the second hemorrhage reaches 60%. Two prominent methods in ruptured aneurysms treatment; surgical clipping and endovascular coil embolization. When the two methods were compared in the ISAT (International Subarachnoid Aneurysm Trial) study in 2002, the endovascular coil embolization method had lower mortality and morbidity rates than surgical clipping, and revealed it to be a preferred method. The main target in endovascular therapy is total occlusion of the aneurysm. No matter how tightly the aneurysm is filled, it is known that the ratio of the coil volume placed in the aneurysmal sac to the volume of the aneurysm is at most 33.3%. An occlusion period that progresses to fibrosis is considered as a result of mechanisms such as decreased aneurysmal blood flow, intra aneurysmal thrombus formation, and electric current used to release the coil. Platinum coils are widely used in the endovascular treatment of intracranial aneurysms. In the studies conducted, it is thought that platinum is inert (chemically inactive) and its effect is weak in the process. However, especially after treatment with a platinum coil of a ruptured aneurysms, it may be thought that the fibrosis process, due to contact with the brain tissue, can be an important issue. In this study, cellular changes emerging due to platinum coil contact with the brain tissue of rats and the role of platinum coil in the development of fibrosis were examined histomorphologically in acute (3 days) and chronic (10 days) periods, and it was aimed to be a project that will guide the knowledge of safety of aneurysm treatment by coil embolization in ruptured aneurysmns. In our study, 40 young-adult Winstar-Albino Rat experimental animals weighing between 250-300 g were used. The rats were produced in the Experimental Medicine Research Unit of Gaziosmanpaşa University and were kept at a constant 21 (± 1) ° C temperature and 50% (± 10) humidity throughout the experiment (the experimental stage of the animal's life). Artificial day/night environment was provided by lighting in 12-hour cycles. 40 rats were randomly divided into 4 groups, 10 in each group, in order to be examined in acute and chronic periods. All attempts to be made to animals were performed under general anesthesia. As antibiotic prophylaxis 20 mg/kg cefazolin sodium 30 minutes before surgery and 3-10 mg/kg xylazine and 90 mg/kg ketamine, during the procedure, were administered to all rats. Animals divided into 4 groups of 10, burr hole was performed from the cranial midline and a platinum coil was placed in the interhemispheric space in 2 groups (acute and chronic), and sham operations were done in the other two groups. Following hemostasis, the layers were closed in the anatomical plan, and animals were sacrificed in order to observe the effects at the end of 72 hours (the acute period) and at the end of the 10th day (chronic period). After sacrification, the brain tissues of the rats were removed and subjected to histomorphological examination. Histological analysis were performed under a light microscope after staining with hemotoxylin and eosin in the Histology Laboratory of Tokat Gaziosmanpaşa University Medical Faculty. The evaluation was conducted in terms of cellular changes and fibrosis development against platinum coil. When the results of our study are evaluated; as a result of the analysis, it was seen that the reparative tissue formed in the treated area was least in the coil+3-day group, and the most reperative tissue formation was in the 10-day group without the coil. The reparative tissue formation, compared to the other groups, was at an average level in the 3-day group without the coil and the coil+10-day group. These two groups were statistically similar to each other and different from the other groups. As a result, it is thought that platinium coil reduces the development of tissue reaction.As well as this may be a disadvantage in terms of complete occlusion development, it is important to reduce the possibility of thromboembolism and to show that the protruding coil parts do not have an irritant effect on the brain tissue. Although a research similar to the experimental study conducted by us could not be seen when the literature was inspected, it is of great importance to evaluate the reactions against platinum coil. Additional long-term studies are needed to evaluate the mechanisms and the reactions against the coils used in the embolization process in order to achieve permanent occlusion. Key words: Subarachnoid hemorrhage, aneurysm, platinum coil.