gms | German Medical Science

Objective: Several options for surgical treatment of adult isthmic spondylolisthesis are available, but it is still on debate how to manage this deformity surgically.

From the biomechanical point of view, our goal should be to achieve a good reductionin order to increase fusion rates avoiding shear forces.

Distraction of the intervertebral space initiates the reduction and leads to neural decompression. Loosening of the screws in dysplastic pedicles is one of the major problems when avoiding the attempt of a good reduction. Time-consuming assemblage and bulky instruments are further disadvantages in the available reduction systems on the market.

Methods: We introduce a new instrument which is placed into the intervertebral space after laminectomy and removal of the disc. This instrument allows a distraction of the intervertebral space independently of the pedicle screws, correction of kyphosis and the reduction. For maintenance, the reposition a posterior lumbar interbody fusion with cages and pedicle screw instrumentation (PLIF and Plates) was performed. We present a cohort of 12 male and 10 female patients with symptomatic lytic spondylolisthesis grade 1–3. In all patients, the so called DR-instrument was used to achieve the reduction and the reposition of the slipped vertebra.

Results: In all patients except one due to insufficient release of the anterior column, a complete reduction was achieved. One dural tear was observed intraoperatively and two screw displacements had to be revised later in a second operation. After one year, one non-union and two breakages of the screws were noticed.

Conclusions: In this paper we present a new instrument which allows distraction, reduction and correction in a simple procedure. The introduction of the instrument belongs to the PLIF, it is easy and it saves operation time. Compared to the results in the current literature dealing with reduction of adult lytic spondylolisthesis, our results are encouraging.