Using geographical information system for spatial evaluation of canine extruded disc herniation

Disc herniation is one of the most common pathologies of the vertebral column in dogs. The aim of this study was to develop a geographical information system (GIS)-based vertebral canal (VC) map useful for spatial evaluation of extruded disc herniation (EDH) in dogs. ArcGIS® was used to create two-dimensional and three-dimensional maps, in which the VC surface is divided into polygons by lines representing latitude and longitude. Actual locations and directions of the herniated disc material were assessed by a series of 142 computer tomographies of dogs collected between 2005 and 2013. Most EDHs were located on the cervical and transitional regions (thoraco-lumbar and lumbo-sacral) and shown at the level of the ven- tro-cranial and ventro-central polygons created. Choropleth maps, highlighting the distribution and the location/direction patterns of the EDHs throughout the VC, were produced based on the frequency of the ailment. GIS proved to be a valuable tool in analysing EDH in dogs. Further studies are required for biomechanical analysis of EDH patterns.