Abstract
Introduction: Five occipitocervical implant systems were compared biomechanically in vitro using nondestructive testing.
Methods: A composite material model of the occiput and upper cervical spine was developed and validated. The specimens were tested using an in-vitro purpose build test rig. Instrumentation was from the occiput to C5 and included five constructs in current clinical use. Biomechanical testing parameters included axial rotation, flexion/extension and lateral bending. Nondestructive pure moments were applied to C5 using a system of cables and pulleys loaded by a materials testing machine (Hounsfield Ltd. UK) Angular displacement of the specimen under load was measured using the Zebris System (Zebris Medizintechnik, GMBH, Germany) which collects and stores three-dimensional space co-ordinates by means of attached ultrasonic markers. Mean maximum angular displacement was calculated from a series of five test cycles for each construct. Statistical significance was determined using a one-way analysis of variance (ANOVA) combined with a LDS test at 95% confidence.
Results: Statistically significant differences were shown in the initial stiffness of current implant constructs used for stabilization of the occipitocervical junction. The Zebris system was also validated as an accurate and efficient 3-D motion analysis for cervical spine biomechanical research.
Abstracts prepared by Mr. A. J. Stirling, FRCS, and Miss A. Weaver. Correspondence should be addressed to Miss A. Weaver at the Research and Teaching Centre, Royal Orthopaedic Hospital, Northfield, Birmingham, B31 2AP, UK
BritSpine 2002, the second combined meeting of the British Association of Spinal Surgeons, the British Cervical Spine Society, The British Scoliosis Society and the Society for Back Pain Research, took place at the International Convention Centre in Birmingham UK between 27th February and 1st March 2002. The following presentations and posters were given and displayed.
