Transdiscal L5-S1 screws for the treatment of adult spondylolisthesis.

Purpose: The aim of the study was to evaluate clinical and radiographic outcome of patients treated with a modified Grob technique analysing the advantages related to increased mechanical stability.

Methods: 30 patients that underwent "in situ" fusion for L5-S1 spondylolisthesis were evaluated. All patients presented a low-dysplastic developmental L5-S1 spondylolisthesis. Patients were divided into two groups: A, in which L5-S1 pedicle instrumentation associated with transsacral screw fixation was performed, and B, in which L5-S1 pedicle instrumentation associated with a posterolateral interbody fusion (PLIF) was performed.

Results: Patients treated with transdiscal L5-S1 fixation observed a faster resolution of the symptoms and a more rapid return to daily activities, especially at 3-6 months' follow-up. The technique is reliable in giving an optimal mechanical stability to obtain a solid fusion.

Conclusions: The advantages of this technique are lower incidence of neurologic complications, speed of execution and faster return to normal life.