Terminated at request of FDA

The purpose of this study is to assess the safety and fusion rates following posterior lateral fusion with the Dynesys Spinal System used as an adjunct to fusion and compare to literature control.

Study is meant to assess the safety and fusion rates following posterior lateral fusion with the Dynesys Spinal System.

Inclusion Criteria:

1. Skeletally mature between the ages of 20-80
2. Candidate for posterior lateral fusion between T1-S1 with autograft
3. Degenerative spondylolisthesis with evidence of neurologic impairment or failed previous fusion (pseudoarthrosis)
4. Symptoms of leg and/or back pain
5. Non-responsive to conservative/non-surgical treatment for at least three (3) months
6. Must be willing and able to comply with study requirements; including complete necessary study paperwork and return for required follow-up visits

Exclusion Criteria:

1. Active systemic or local infection
2. Obesity
3. Use of interbody device
4. Pregnancy
5. Mental illness
6. Incarceration
7. Alcohol or drug abuse
8. Severe osteoporosis or osteopenia
9. Use in the cervical spine
10. Sensitivities/allergy to metals, polymers, polyethylene, polycarbonate urethane and polyethylene terephthalate
11. Soft tissue deficit not allowing sound closure
12. Any medical or physical condition that would preclude the potential benefit of spinal implant surgery
13. Congenital abnormalities, tumors or other conditions that would prevent secure component fixation that has the potential to decrease the useful life of the device
14. Active malignancy or other significant medical comorbidities
15. Any medical or mental condition which would put the patient at high risk due to the severity of surgery
16. Inadequate pedicles of the thoracic, lumbar and sacral vertebrae
17. Patient unwilling or unable to follow postoperative instructions

Baseline variables were summarized for all subjects who were eligible, enrolled in the study and underwent a surgical procedure where the Dynesys® Spinal System was implanted.

Adverse events were collected from the time of surgery through the participants last visit; up to 48months.

Any unfavorable and unintended sign, symptom, or disease associated with the use of an investigational product, whether or not related to the investigational product, taking into consideration the patient history, surgical history, histological analysis as well as explants evaluation. Events may be complications, observations (including radiographic), change in patient condition or related/unrelated death. A change indicating worsening as reported on an assessment is an adverse event.

Early termination lead to a significant subset of subjects to not make it to the final follow up time interval. This resulted in small numbers of subjects analyzed for fusion and literature control was not used as planned originally in protocol.