Subpial Aspirated Cerebellar Tonsils in Pediatric Chiari I Malformation: anatomopathological study

Abstract

Introduction: Chiari Malformation (CM) is a condition in which ectopy or herniation of components of the posterior cranial fossa to theforamen magnum are present, and can be divided into four types. Type I (CM-I) occurs when there is protrusion of only the cerebellartonsils into the cervical spinal canal. One of the available therapeutic options is subpial aspiration. Previous anatomopathologicalstudies showed that the main alterations in the aspirated tonsils were the loss of Purkinje cells, Bergmann gliosis, cortical atrophyand neuronal changes due to hypoxia; all of them secondary to the aggression to the nervous tissue over time. These changes leadto gradual loss of function of the tissue, with compensation by other structures. Therefore, when subpial aspiration of the herniatedtonsil is performed in adults, there are no negative consequences to the patient in the future, as concluded by many studies targetingadults with CM. However, studies in children with CM are scarce, which means that we cannot affirm in which age the histologicalchanges occur. Hence, we cannot determine whether or not the surgical removal of this tissue in childhood leads to future losses tothe patient. Objective: To analyze the main histological aspects of cerebellar tonsils in children with Chiari I Malformation whounderwent subpial aspiration, to help clarify the natural history of this pathology, as well as to help determine the prognosis of thispopulation when treated with this technique. Method: We analyzed the histopathology of the tonsils removed with subpial aspirationtechnique, in several hospitals of João Pessoa, Brazil, from children diagnosed with Chiari I malformation. Results: The slides of alltonsils showed the same histological changes: Bergmann gliosis, loss of Purkinje cells, atrophy of the cerebellar cortex and meningealfibrosis. The obtained results were similar to the ones found in previous studies carried out in adults. Conclusion: The cerebellaranatomopathological alterations secondary to Chiari I Malformation, which leads to loss of tissue function, seem to appear early inlife, suggesting the safety of the subpial aspiration in pediatric patients. However, more extensive studies and long-term follow-up ofpatients are needed to establish with more precision the natural history of the disease.