Dynamic Stabilization for Lumbar Spinal Stenosis With Stabilimax NZ® Dynamic Spine Stabilization System

Radiographic:

• Degenerative spinal stenosis of the lumbar spine, central, lateral recess, or foraminal;
• Evidence of the cal sac and/or cauda equina compression, nerve root impingement, hypertrophic facets with canal encroachment, with or without spondylolisthesis, if present, no more than grade 1

General:

• The greater of the patients right and left VAS leg pain score is ≥ 40 mm on a 100 mm scale;
• Zurich Claudication Questionnaire Symptom Severity score greater than 2 on a scale of 1-5;
• Zurich Claudication Questionnaire Physical Function score greater than or equal to 2 on a scale of 1-4;
• Intermittent neurogenic claudication
• At least six months of non-surgical management.
• Skeletally mature patients at least 21 years of age;
• Willing to provide written consent for participation and a Health Insurance Portability and Accountability Act authorization;
• Willing to undergo all study procedures including physical therapy and adhere to the follow-up schedule; and
• No additional surgical treatment is required outside the investigational or control at the time of surgery.

EXCLUSION CRITERIA:

Initial Screening:

• Prior surgery at any lumbar level including the level being treated except for: Lamino/Foraminotomy, Microdiscectomy, IDET, and Percutaneous Discectomy.
• Prior surgery at any lumbar level within one year of enrollment;
• No more than one prior surgery at any lumbar level;
• Previous acute trauma at the treated level within two years of enrollment;
• Primary and predominate diagnosis of discogenic back pain, e.g. torn disc, herniated disc inflamed or irritated disc, or other disc pathology;
• Symptomatic cervical and/or thoracic neurological compromise;
• Significant peripheral neuropathy or acute denervation secondary to radiculopathy, caused by conditions other than spinal stenosis;
• Other neurological pathology that could confound study results;
• Cauda Equina Syndrome;
• Contraindicated for MRI;
• Morbid obesity (BMI > 40);
• Peripheral vascular disease requiring intervention (≥ 50% stenosis of vessel);
• Active systemic or surgical site infection;
• Any significant medical conditions that would represent a significant increase in surgical risk or interfere with normal healing;
• History of psychosocial disorders that could prevent accurate completion of self reporting assessment scales
• Women who are pregnant, lactating or anticipate becoming pregnant within 24 months post-surgery;
• Insulin dependent diabetes mellitus;
• Immunocompromised such as but not limited to Acquired Immunodeficiency Syndrome , genetic deficiencies of the complement system, Severe Combined Immunodeficiency Disease, Thymic Hypoplasia;
• Receiving immunosuppressive therapy
• Receiving long-term steroid therapy. Autoimmune disease;
• Active hepatitis;
• Malignancy of any type within the last five years;
• Previous known allergy to the materials contained in the Stabilimax NZ™ device including nickel, cobalt, chromium, molybdenum, iron, titanium, or Teflon™;
• Participation in another clinical study within four weeks of enrollment, or;
• Receiving Worker's Compensation or is involved in active litigation relating to his/her spinal condition;
• Patients who are prisoners.

Radiographic:

• Gross instability, defined as greater than 3 mm translational motion on flexion/extension studies;
• Degenerative spondylolisthesis or retrolisthesis higher than grade 1
• Degenerative scoliosis > 10° at any level(s) in lumbar spine
• Lateral listhesis on A-P X Ray
• Spondylolysis at any level in lumbar spine
• Isthmic Spondylolisthesis at any level in lumbar spine
• Spondylolisthesis at more than one lumbar level;
• DEXA score equal to or below -2.5 T;
• Pathological vertebral fracture;
• Metastases to the spinal vertebra; Paget's disease of bone; Osteomalacia; Pars defect or facet fracture;
• Facet arthropathy at the level(s) to be treated is less than grade 2 and greater than grade 3 according to the Fujiwara scale;
• More than moderate disc degeneration defined as: > 66% loss of disc height compared to the normal, superior adjacent level; and/or moderate to Severe Osteophyte formation;
• Congenital lumbar spinal stenosis;
• Estimated interpedicular distance of less than 30 mm.