Intraoperative malposition of pedicle probe or screws: a potential cause of the acceleration of degeneration in superior adjacent intervertebral disc

Abstract

Adjacent segment degeneration (ASD) is considered as a long-term complication of spinal fusion procedure. Numerous clinical studies have reported some factors related with ASD, but few could address the reason why the incidence of caudal ASD is significantly lower than that of cranial ASD. Because the pedicle of vertebral arch is closer to the superior endplate of vertebrea and its cranial intervertebral disc, there might be some possibilities of malpositions of pedicle probe or screws into the superior vertebral endplate or disc during the procedure of posterior intervertebral fusion. A number of evidences have showed that puncture of intervertebral disc will result in disc degeneration. Thus the authors put forward the hypothesis that intraoperative malposition of pedicle probe or screws might be a cause of ASD at cranial segments.