1127 Revealing the Confusion of the Evolution of the Term Sagittal Stratum. Historical Overview and Systematic Literature Review

INTRODUCTION: Following Andreas Vesalius’ differentiation of white and gray matter in 1543, the fiber dissection technique stands as one of the earliest methods used to demonstrate the internal structures of the brain. Throughout the historical evolution of white matter dissection, debates have arisen about dissection methodology, nomenclature, and efforts to adopt findings from primates to the human brain. METHODS: Original reports from the 17th through the 20th centuries were hand-searched from historical neurosurgical books from the personal collection of the senior author and a digital literature review was conducted in Internet databases. RESULTS: In 1892, Heinrich Sachs was the first to introduce the term sagittal stratum to define the parasagittally oriented white matter fiber bundle in posterior regions of the hemisphere. Despite significant advancements in histological methods, radiological imaging techniques, and fiber dissection methodology, the definition of the sstr continues to exhibit variations in the current literature. Despite these discrepancies, the sstr holds substantial functional importance as a major white matter pathway facilitating communication between frontal, parietal, temporal, and occipital cortices. Therefore, gaining a precise understanding of the sstr is crucial not only for enhancing our knowledge of neuroanatomy but also for guiding neurosurgeons in resecting tumors located in the atrium or performing selective amygdalohippocampectomy. CONCLUSIONS: Through a comprehensive investigation of the literature and historical background of white matter dissection, this study unveils the early synonymous descriptions of the sstr and addresses the existing discrepancies surrounding it. Although our perspective on the sstr is that this unique structure contains fibers from all three fiber systems (association, commissural, and projection), further research and consensus-building efforts are necessary to establish a unified understanding of this structure.