Biomechanics of the Dynesys System

The Dynesys Dynamic Stabilization System combines the surgical approach of traditional spinal fusion with the philosophy of dynamic stabilization, using flexible materials to stabilize the spine while preserving anatomical structures.

The system uses three proprietary components to stabilize the spine:

• Titanium screws anchor the system to the spine
• Polycarbonate urethane (PCU) spacers limit spinal extension
• Polymer cord acts as a tension band to limit spinal flexion

The system is placed under tension creating a dynamic interaction between the components.

When the patient bends forward:

• The cord engages and acts as a tension band
• Overall flexion is limited

When the patient bends backward:

• The screw heads interact with the spacer
• The spacer resists the compressive load
• Overall extension is limited

Flexion

Dynesys LIS, Dynesys Top-Loading System & Zimmer  DTO System  

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.

Dynesys LIS, Dynesys Top Loading System & Zimmer  DTO System

Contraindications of the Dynesys Spinal System are similar to other commercially available posterior spinal fixation systems. Contraindications include but are not limited to the following:

• Scoliosis > 10° at the affected level(s)
• Degenerative spondylolisthesis or retrolisthesis > grade 1
• Isthmic spondylolisthesis at the segment(s) to be stabilized dynamically (Dynesys)
• Treatment of the thoracic and cervical spine
• Unilateral Dynesys System application
• Previous lumbar fusion attempt(s) at the segment(s) to be stabilized dynamically (Dynesys)
• Previous facetectomy at the segment(s) to be stabilized dynamically (Dynesys)
• Local Bone tumors
• Vertebral fractures
• Marked osteoporosis or osteomalacia as evidenced by plain film radiographs or history of fractures
• Insufficient bone structures, impairing the anchorage of the implant
• Signs of infection
• Allergic reaction to implant components
• Any patient unwilling to follow postoperative instructions
• Pregnancy

• Patient history of chemical dependency or significant emotional or psychosocial disturbance may have a negative impact on treatment outcome.
• Implants are for single use only. Do not reuse.
• Do not use any component if damage is found or caused during setup or insertion.
• Unless the Zimmer DTO Implant is being used, components of spinal fixation systems other than Zimmer Companies should not be used with the components of the Dynesys Spinal System. Only the OPTIMA ZS Spinal System, including the OPTIMA ZS Transition Screw, may be used in combination with the Zimmer DTO Implant. Each system must be implanted using the appropriate instruments and surgical technique as defined in the respective Surgical Technique Manuals. The instruments for the different systems must not be commingled or used interchangeably. No liability is accepted for other products of third parties that are used by the purchaser or user.
• Unless the Zimmer DTO 5.5 Implant is being used, components of spinal fixation systems other than Zimmer Companies should not be used with the components of the Dynesys Spinal System. Only the Sequoia System or Instinct Java System may be used in combination with the Zimmer DTO 5.5 and Zimmer Universal Transition Screw Implant. Each system must be implanted using the appropriate instruments and surgical technique as defined in the respective Surgical Technique Manuals. The instruments for the different systems must not be commingled or used interchangeably. No liability is accepted for other products of third parties that are used by the purchaser or user.
• Use only instruments specifically designed for use with these devices to help ensure accurate surgical implantation.
• The load-bearing capacity of the implant can be compromised by notching, scratching, or striking.
• Improper selection, placement, positioning, and fixation of the implant components may result in unusual stress conditions reducing the service life of the implants.
• Do not use this product for other than labeled indications (off-label use).

• The Zimmer DTO and Zimmer DTO 5.5 Implant requires specific assembly; refer to the Surgical Technique Manual for the assembly instructions.
• When using the Zimmer DTO, Zimmer DTO 5.5 and Zimmer Universal Transition Screw Implant, verify that no component of the implant has become loose in the packaging.
• Verify that the Zimmer DTO, Zimmer DTO 5.5 and Zimmer Universal Transition Screw Implant is fully assembled prior to implantation.
• The Zimmer DTO Implant rods 40-100mm long are supplied pre-bent and should not be further contoured.
• The Zimmer DTO Implant rods 150mm long are supplied straight and may be further contoured carefully following the Surgical Technique Manual.
• The Zimmer DTO 5.5 Implant rods 40 and 50mm long are supplied pre-bent and should not be further contoured.
• The Zimmer DTO 5.5 Implant rods 60-100mm long are supplied pre-bent and may be further contoured carefully following the Surgical Technique Manual.
• The Zimmer DTO 5.5 Implant rods 150mm long are supplied straight and may be further contoured carefully following the Surgical Technique Manual.
• Remove any protective devices prior to the final implantation (i.e. protective caps or bags).
• Continued surveillance for new or recurrent sources of infection should be continued as long as the device is in place.
• Implants must not be machined or altered in any way, unless this is expressly envisaged in the design and in the surgical technique.
• The rules of asepsis are to be observed during the implantation.
• The patient must be told that implants can affect the results of computer tomography (CT) or magnetic resonance imaging (MRI) scans.
• The device has not been evaluated for safety and compatibility in the MR environment.
• The device has not been tested for heating or migration in the MR environment.

The following adverse effects have been reported:

• Implants or implant parts can fracture, become loose or undergo excessive wear, or their function may be impaired.
• Early or late infections.
• Bone fractures following overloading, incorrect choice of the implant size or weakened bone substance.
• Soft tissue and/or (temporary or permanent) nerve damage.
• Wound hematoma and slow wound-healing.
• Cardiovascular disorders.
• Muscle impairment.
• Limited mobility.
• Further degeneration.
• Adjacent-segment syndrome.
• Dural laceration, pseudomeningocele, fistulisation, persistent loss of cerebrospinal fluid, meningitis.
• Neurological disorders.
• Neuroma
• Postoperative changes to the spinal curvature and/ or loss of correction, alignment and/ or disc height.
• Hernia of the nucleus pulposus, ruptured disc or degeneration in, above or below the operated segment.
• Fracture, resorption, damage or penetration of a spinal bone.
• Pain.
• Urinary retention or loss of bladder control or other types of disorders of the urogenital system (e.g., retrograde ejaculation).