Journal de la colonne vertébrale

Combined Dynamic and Rigid Multilevel Posterolateral Lumbar Fixation Systems in Prevention of Adjacent Segment Disease

Abstract

Lyras DN and Kottas GD

Introduction: The gold standard in the treatment of lumbar degenerative spinal diseases is the posterolateral fusion with rod and screws. Semi-rigid systems were first designed to stabilize the abnormal segment and to unload degenerated discs and facet joints. One commonly observed consequence of fusing spinal motion levels has been adjacent segment disease (ASD). Due to prevention of ASD is a complicated and controversial topic, the aim of this study was to assess the role of combined dynamic and rigid posterolateral fixation systems in prevention of ASD.

Patients and Methods: A total of 76 adult patients with various lumbar spine pathologies, treated with posterior fusion and pedicle screw fixation between T12 and sacrum were included in this study. The prevalence of radiological and clinical ASD was measured and the functional outcome of the patients was evaluated using the Oswestry questionnaire.

Results: Evidence of radiographic ASD was noted in 6 of the 76 patients (7.9%), of whom one patient was symptomatic (16.67%). The mean preoperative Oswestry score was 27.2 ± 20.7 and the mean postoperative Oswestry score was 15.4 ± 20.3. There was a significant difference between the 2 scores (p=0.027). The mean postoperative lumbar lordosis was -53° ± 2.08 and the pelvic incidence 61° ± 3.12. Related to the complications, 6 patients with superficial wound infections, one patient with deep venous thrombosis (DVT), and one patient with ASD were reported.

Discussion: In our study, the very low incidence of ASD is achieved by the mean of preservation of the top facet joint, correction and preservation of coronal and sagittal balance, preservation of motion in the lumbar spine with the use of semi-rigid devices, and early rehabilitation accompanying by the training of the patient regarding to the body balance. Semi-rigid fixation significantly reduces the risk of screw fracture by the absorption of the stress on the interpedicular damper and enhances the bone fusion by maintaining constraints on the cages which remain under a compressive load.