Spinal fusion still is considered to be the most appropriate treatment for lumbar spinal disease not responding to conservative measures. Various forms of lumbar instability require surgical stabilisation. As an alternative to fusion, mobile, dynamic stabilisation restricting segmental motion would be advantageous under certain conditions, allowing greater physiological function and reducing the inherent disadvantages of rigid instrumentation and fusion. The “Dynamic Neutralization System for thèeSpine” is a pedicle screw system for mobile stabilisation, consisting of titanium alloy screws connected by an elastic synthetic compound, controlling motion in any plane (non-fusion system). Clinical success after solid fusion is unpredictable because it does not necessarily prevent painful loading across the disc, and it may also interfere with maintenance of sagittal balance in various postures. This system reduces movement both in flexion and extension and appears to be better. These study results compare well with those obtained by conventional procedures; in addition to which, mobile stabilisation is less invasive than fusion. Long-term screw fixation is dependent on correct screw dimensions and proper screw positioning. The natural course of polysegmental disease in some cases necessitates further surgery as the disease progresses. Dynamic neutralisation proved to be a safe and effective alternative in the treatment of unstable lumbar conditions.

Surgical treatment of adult kyphosis is an old procedure (Ferguson, Hallock, Roaf, Moe). According to conventional concepts, surgery should be reserved for adolescents with curvatures exceeding 75° or with rapidly progressive kyphoses despite treatment with braces or casts and adults with symptomatic curves greater than 65°. Therefore, it is important to evaluate these factors, in addition to the angular level of the kyphosis, to determine the most suitable type of treatment.

The presence of pain should not be considered an absolute indication for treatment in view of the disease’s benign natural evolution. Thus, the only true indication for treatment is the severity of the angle of the curvature, which has been shown to progress over time. Generally, in Scheuermann kyphosis it is suggested that three or four double pedicular transverse or laminar hook configurations be used on the spine above the apex of the kyphosis; this gives an excellent hold on the posterior arch and minimises the risk of neurologic impairment. The use of a transpeduncular screw in the first two lumbar levels increases the stability of the assembly.

In cases of extreme vertebral rigidity posterior multilevel osteotomy is also indicated. In cases of extreme vertebral rigidity anterior arthrodesis is indicated. This is performed by means of an intrathoracic approach or thoracoabdominal retropritoneal approach. The technique makes it possible to resect the anterior longitudinal ligament and to perform multiple discectomies at apical vertebral levels. It is also possible to perform combined anterior and posterior arthrodesis.