SpineShape System IV
System IV is an implant system, which relies on the pedicular fixation. The pedicular fixation (introduced by Prof. Raymond Roy-Camille in the 1960ties) nowadays belongs to the standard procedures in the spine surgery.
In this operative-technique only those steps are mentioned, which specifically refer to the System IV. Regarding the approaches, two widely spread standard techniques are known, namely the medial and the lateral approach. The medial approach is normally used when the spinal canal must be simultaneously opened, e.g. for treating a disc prolapse. The lateral approaches (acc. to Wiltse) are in so far advantageous as the pedicles can be accessed along their lateral axis and that muscular scars are thus minimized.
System IV is basically suitable for the entire lumbar spine, i.e. from L1 to S1 (sacrum). For patients with small vertebral bodies it should previously be verified whether the upper vertebrae (e.g. L2, L1) allow accommodation of the provided pedicle screws and connection rods.
In a nutshell
Selection guide for the correct rod flexibility
- A low-flex rod shall be used when a patient requires a high degree of stabilisation, where a later spontaneous fusion would be desirable.
- A mid-flex rod shall be used when a patient requires a medium degree of stabilisation, e.g. after a decompression surgery with a light iatrogenic destabilisation.
- An high-flex rod shall be used when a patient requires a low degree of stabilization, e.g. to protect the nerve roots, to limit motion on the facet joints or to avoid disc bulging. The high-flex rod has control tasks rather than load carrying tasks.
Note: The flexibility also varies with the distance between the pedicle screws. The further apart the screws, the more flexibility is achieved.
For the low-flex and mid-flex rod, as an option, a version with a stepped cross section (called Varistab™) is available, which serves to connect and protect the adjacent segment with double (axial) flexibility. The same pedicle screws can be used for the stepped region; only the length of the clamp screw needs to be different. For the standard rod (prismatic) the short clamp screw (Art.-Nr. 21.019.11-000-S) is used and for the Varistab™ (stepped) the long clamp screw (Art.-Nr. 21.019.11-100-V) is used.
*) hypermobility with antelisthesis / hypomobility with retrolisthesis when decompressed
**) treatment with SpineShape feasible but not preferred