Computer visualisation of the moving human lumbar spine.

Disorders of the spine which lead to back pain are often mechanical in origin and, despite extensive research, diagnosis of the underlying cause remains problematical, yet back pain is one of the most common rheumatological symptoms presented to the general practitioner. Diagnosis must frequently be based upon evidence gathered at the segmental level which invariably means that imaging is used in the process. In addition, surgical fixation is increasingly used when the spinal column is considered to exhibit instability. A solid model of the spine creates the possibility of visualising spine motion, of assessing the effects of loading of the spinal column in conjunction with finite element analysis to investigate the consequences of vertebral fusion, and of planning surgical intervention. Such a model could also be valuable in medical education and for demonstrating spine motion to a patient to highlight abnormalities or the effects of treatment. This paper describes a three-dimensional visualisation of the human lumbar spine which runs on a personal computer operating under the Windows environment. The user interface enables the clinician to select the viewpoint for the spine model to allow the motion to be studied from different angles. Motion data are currently acquired from fluoroscopic image sequences but the model could be used to display data from different imaging modalities when they are developed sufficiently for spine motion studies.