Dynesys

Dynesys system (Zimmer Spine, Warsaw, IN) is composed of two titanium pedicle screws connected by a cylindrical polycarbonate urethane (PCU) spacer with a tensioned polyethylene terephthalate (PET) cord tunneled through the PCU spacer. The PET cord resists tensile forces and provides resistance to spine flexion similar in concept to the Graf system. However, the Dynesys PCU spacer resists compression during extension and thereby maintains foraminal height and decreases load to the posterior annulus.

• Dynesis VIDEO ANIMATION
• Dynesys.SGT-ZimmerBiomet.pdf

The Dynesys system is FDA approved as an adjunct device for spinal fusion, however, through controlled motion and indirect decompression, the Dynesys system attempts to decrease discogenic low back pain while minimizing the risk for adjacent segment degeneration.

The Dynesys Dynamic Stabilization System was designed as a more physiologic system of spine stabilization. The system Holds the segments in a more natural anatomic position using non-rigid materials, Preserves natural anatomical structures as much as possible and Constrains spinal motion (“internal splint”)

The Dynesys Spinal System is indicated to provide spinal alignment and dynamic re-stabilization in skeletally mature patients up to 5 contiguous levels from L1 to S1 (Dynamic Neutralization®). The system is intended to be used without bone graft for the following indications.

• Primary discopathy (spondylosis) and spondylarthrosis in combination with:
• Discopathy hypomobile; degenerative retrolisthesis (up to grade I)
• Discopathy hypermobile; degenerative antelisthesis (up to grade I)
• Degenerative pseudo-spondylolisthesis (up to grade I)
• Mono- or multisegmental lumbar stenosis with or without olisthesis.When both the Dynesys Spinal System and the OPTIMA™ ZS Spinal System are used on adjacent levels, they must be used with the Zimmer® DTO® Implant, rod-cord combination implant, and the U & I Corporation OPTIMA ZS Transition Screw. The intended use for each level is as specified for each system.

Benefits of the Dynamic Stabilization Systems

1. Patient-Specific:Intraoperatively measure and cut the spacer to accommodate each patient’s natural anatomical structure
2. Designed To Be More Load-Sharing vs Load-Bearing:
3. Designed to minimize stress-shielding:Provides a controlled range of motion in flexion and extension
4. Anatomy Preservation
5. -Far-lateral, low profile screw placement preserves facet joints
   -The Wiltse paraspinal surgical approach reduces disruption to the posterior anatomy
6. Versatility
   The Zimmer DTO implant allows surgeons to treat different stages of degeneration at contiguous levels.

About Pedicle Screw/Rod–Based Dynamic Stabilization Devices

Dynamic stabilization is a surgical technique designed to allow for some movement of the spine, while maintaining enough stability to prevent too much movement. Pedicle-based dynamic devices were first designed to stabilize the abnormal segment and to unload degenerated discs and facet joints, while maintaining the same level of normal motion.By unloading the pressure on the degenerated disc and facets, pedicle-based dynamic devices have the potential to reduce pain associated with these anatomical structures. Furthermore, these devices can be used to prevent adjacent-segment disease, either by replacing the whole construct with dynamic rods or by “topping off” the rigid instrumented segment with pedicle-based dynamic devices, avoiding an abrupt change from a rigid construct to the more mobile adjacent segment. It has also been argued that using pedicle-based dynamic devices can promote better fusion because of micromovements across endplates, and can protect from implant failure because of better load sharing through the implant. Finally, these devices can be used to stabilize posterior iatrogenic destabilizing surgery, such as wide laminectomy and facetectomy.

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