A Postmarket Surveillance Study of the Paradigm Spine Dynamic Stabilization System (DSS)

Paradigm Spine Dynamic Stabilization System (DSS) study is a prospective, multi-center,
literature controlled study.

Inclusion Criteria:

- Patient is skeletally mature (21-85 years old).

- Patient has degenerative spondylolisthesis (Grade 1-3) with objective evidence of
neurologic impairment, kyphosis, and/or failed previous fusion (pseudarthrosis) at
index level.

- Capable and willing to comply with the requirements unique to the study, adhere to the
post-operative treatment and management program, and return for required follow-up
examinations.

- Surgeon has determined that DSS™ System is an appropriate treatment for the patient
without regard to the study.

Exclusion Criteria:

- The need for interbody cages, allograft, or any other assistance during surgery.
Device is only to be used with autograft per FDA approved indications.

- Any medical, mental or surgical condition precluding the potential benefit of spinal
surgery or surgery in general.

- Acute or chronic systemic, spinal or localized infections.

- Active, severe systemic and metabolic diseases.

- Obesity defined as Body Mass Index > 35.

- Subject is pregnant or interested in becoming pregnant in the next 36 months.

- Dependency on pharmaceutical drugs, drug abuse, or alcoholism.

- Lack of patient cooperation.

- Foreign body sensitivity to the implant material.

- Degenerative scoliosis greater than 25 degrees.

- Grade 4 degenerative spondylolisthesis (>75% slip).

- Significant osteopenia A screening questionnaire for osteopenia, SCORE (Simple
Calculated Osteoporosis Risk Estimation), will be used to screen patients who require
a DEXA bone mineral density measurement. If DEXA is required*, exclusion will be
defined as a DEXA bone density measured T score of ≤ -1.0 (The World Health
Organization definition of osteopenia).

- Soft tissue deficit not allowing wound closure.

- Congenital abnormalities, tumors or other conditions that would prevent secure
component fixation that has the potential to decrease the useful life of the device.

- Inadequate pedicles or vertebral body geometry of the thoracic, lumbar and sacral
vertebrae.

- Bony lumbar spinal stenosis not related to the primary degenerative spondylolisthesis
indication.

- Pars defect.

- Clinically compromised vertebral bodies at affected level due to current or past
trauma.

- Prisoner or ward of the state.

- Currently in litigation regarding a spinal condition.

- Known allergy to titanium, titanium alloys, CoCrMo, polyethylene or MR contrast
agents.

- Is currently involved in a study of another investigational product for similar
purpose.