Discrimination of amount of spinal flexion for movements made with and without vision after lumbar disc replacement

Discrimination of differences between small lumbar flexion movements made when standing may differ depending on whether vision is available. Dependence on general vision during trunk movements may be increased following surgery, in which an intervertebral disc is replaced with a prosthetic disc. This study investigated whether the availability of vision changed discrimination of small differences in lumbar forward flexion movement when standing for patients with lumbar disc replacement and healthy peers. 20 volunteers without a history of back pain and 20 with disc replacement undertook a 100-trial sequence of forward flexion movements to a set of physical stops, making an absolute judgement as to the position after each movement. General (nontarget) vision during the movement was available or removed randomly trial by trial. Availability of vision did not affect discrimination of flexion movements of the lumbar spine either in normal healthy individuals or those with disc replacement.