[Treatment of spondylolisthesis. Operation in situ or repositioning spondylodesis]

The indication for operative treatment of spondylolisthesis in children and juvenile patients relies mainly on the progressive slipping of the vertebra, with consecutive deformation, on the other hand on neurological disorders, that may be seen as rigid lumbar extension with contractation of hip and knee joints. In the adult patient the main reason for treatment is the painful instability, often accompanied by root pain caused by degenerative changes as a result of repairment. The treatment consists of comlete reduction of the slipping vertebra, and reconstruction of the physiological lumbar lordosis through a postolateral and anterior interbody fusion. In case of additional compression of neurological structures, an extensive decompression must be performed. Today it is possible to reposition nearly ever spondylolisthesis, even ankylosed spondyloloptosis. In some cases it is necessary to performe the reposition step by step in two sessions in order to allow the neurological structures to accomodate. Finally you reach through a complete reposition a physiological curve with correct impact of the biomechanic forces and a harmonic relation between posterior compression and anterior axial force. A complete reposition with an negativ angle in the slipping segment brings the axial force back into physiological position and prevents early degenerative changes in the neighbouring segments. A posterior fusion in situ can not reduce the pathological biomechanics and has to lead to a high rate of pseudarthrosis with an increase of the anterior slipping. Even anterior fusion only is not sufficient, as the posterior inter-articular portion remains divided, the disposition or dysplasia of the facett joints increases the segmentmovement. As a result you see resorption and pseudarthrosis of the anterior fusion. Only in case of undamaged discs and ligaments in juvenile patients without anterior slipping a try with a posterior laminoplastic is allowed.