A-MAV™ Anterior Motion Segment Replacement

Inclusion Criteria:

• Has back and/or radicular pain with degeneration of the disc as confirmed by patient history, physical examination, and radiographic studies with one or more of the following factors:

  • instability as defined by > 5° angulation
  • osteophyte formation of facet joints or vertebral endplates
  • decreased disc height, on average by >2mm, relative to the next adjacent vertebral segment
  • scarring/thickening of ligamentum flavum, annulus fibrosis, or facet joint capsule
  • herniated nucleus pulposus
  • facet joint degeneration/changes
  • vacuum phenomenon
• Has single-level symptomatic degenerative involvement from L4-S1 requiring surgical treatment
• Has intact facet joints at the involved vertebral levels documented by CT and/or MRI
• Has preop Oswestry score≥30
• Has preop back pain score ≥8
• Age 18 to 70 yrs, inclusive and is skeletally mature
• Has not responded to non-operative treatment for 6 mos
• If child-bearing potential, patient is non-pregnant, non-nursing, and agrees not to become pregnant for 1 yr after surgery
• Is willing and able to comply with the study plan and sign the Patient Informed Consent Form

Exclusion Criteria:

• Has primary diagnosis of a spinal disorder other than DDD at involved level
• Had previous anterior lumbar spinal surgery at involved level
• Had previous posterior lumbar spinal fusion surgical procedure at involved level
• Had prior posterior lumbar surgery resulting in significant muscle/ligament morbidity, not including facet saving techniques
• Requires surgical intervention at more than 1 lumbar level
• Has severe pathology of facet joints of involved vertebral bodies
• Has facet arthritis or any posterior element insufficiency
• Has spondylolisthesis
• Has mid-sagittal stenosis of <8mm, based on remaining canal diameter
• Has rotatory scoliosis at involved level
• Has lumbar scoliosis with >11° sagittal plane deformity
• Had previous trauma to L4, L5, or S1 levels in compression or burst
• Meets any of the following criteria: Previous diagnosis of osteoporosis, osteopenia, or osteomalacia; postmenopausal Non-Black female over 60 yrs of age and weighs less than 140 pounds; postmenopausal female that has sustained a non-traumatic hip, spine or wrist fracture; male over age 60 that has sustained a non-traumatic hip or spine fracture. If Yes to any of these, a DEXA scan is required. If level of BMD is -3.5 or lower or -2.5 or lower with vertebral crush fracture, the patient is excluded
• Had previous lumbar spinal fusion at adjacent level
• Bone growth stimulator use in spine
• Has obesity defined by BMI greater than or equal to 40
• Has arachnoiditis
• Has a non-contained or extruded herniated nucleus pulposus with acute nerve root compression
• Has condition that requires postop medications that interfere with bone metabolism, such as chronic steroid use or prolonged use of non-steroidal anti-inflammatory drugs, excluding routine perioperative, non-steroidal anti-inflammatory drugs. Does not include low dose aspirin for prophylactic anticoagulation
• Has overt or active bacterial infection, either local or systemic and/or potential for bacteremia
• Has presence or prior history of malignancy (except for basal cell carcinoma of skin)
• Has documented metal allergy, titanium alloy intolerance or cobalt-chrome-molybdenum alloy
• Is mentally incompetent. If questionable, obtain psych consult
• Has a Waddell Signs of Inorganic Behavior score of 3 or greater
• Has chronic or acute renal and/or hepatic failure or prior history of renal and/or hepatic parenchymal disease
• Is prisoner
• Is pregnant
• Is an alcohol and/or drug abuser as defined by currently undergoing treatment for alcohol and/or drug abuse
• Has history of autoimmune disease
• Has received treatment with an investigational therapy within 30 days prior to implantation surgery or treatment is planned during 24 months following the implantation surgery
• Has history of any endocrine or metabolic disorder known to affect osteogenesis
• Has any disease that would preclude accurate clinical evaluation