The influence of nucleotomy on the biomechanical behavior of the intervertebral disc

Aim of the study: The purpose of the present investigation was to determine the significance of the technique of nucleotomy for the biomechanical prop erties of the intervertebral disc. Methods: From 29 human cadavers the lumb ar-vertebral segment L2/3 was taken. The laminae were removed and the segme nt was tested by an mechanical testing device. Measurements were taken unde r physiological loads in flexion/extension, lateral bending and rotation di rection. There after nucleotomy was simulated by four different procedures: perforation of the anulus with a diameter of 3 mm, rectangular excision (1 x 1 cm) of the anulus, discotomy with 3 g and 6 g nucleus pulposus. In eac h step the measurement was repeated. Results: The size of the defect in the anulus fibrosus did not have significant influence on the stiffness of the disc. There was a significant. relation between quantity of removed disc m aterial and flexibility of the motion segment. Conclusion: The quantity of removed nucleus pulposus plays a crucial role in the segmental mobility whe ras the size of the approach in the anulus fibrosus, f.e. endoscopic with a hole diameter of 3 mm or conventionally with a rectangular defect of 1 x 1 cm, did not influence mobility.