In the past years, for the treatment of lumbar multilevel stenosis with instability, DYNESYS® instrumentation has been largely used at our department. However, the long construct of DYNESYS® instrumentation (from T11/T1 to S1) presented a weak point at the lumbosacral fixation, with possible loosening of the S1 screws. Therefore, we preferred to adopt hybrid fixation, such as the DYNESYS® transition option (DTO): This implant combines the DYNESYS® Neutralization System with the Optima Spinal System, i.e., a dynamic fixation combined with a rigid one. The rigid fixation was used distally in the construct, from L4 (or L5) to S1. DTO instrumentation resolved the problem of L5–S1 fixation. Concerning adjacent segment disease (ASD) with this long hybrid instrumentation, the prevalence of radiographic ASD was 10.0% in our series, at a minimum of 5 years of follow-up. Because the observed clinical outcomes were good and there was no case of implant breakage or screw loosening, this experience supports the efficacy, safety, and reliability of the hybrid posterior fixation system in this disease.