a pilot study of the intercushion disc nucleus prosthesis (dnp) in patients receiving discectomy

Conditions: Disk, Herniated

Summary: the primary endpoints of the investigation will include assessment of the maintenance of disc height demonstrated by radiographic evidence based on plain radiographs and mri and relief of pain as measured by visual analog scale (vas) at six months post-surgery. it is anticipated that outcomes with the intercushion disc nucleus prosthesis (dnp) will be comparable to or better than the historical published results for discectomy alone.

all patients will be followed for at least 24 months once enrolled in the study. clinical evaluations will be conducted before surgery (baseline), intraoperative, 2 week (± 1 week), 6 week (± 1 week), 3 months (± 2 weeks), 6 months (± 1 month), 12 months (± 2 months) and 24 months (± 2 months).

Eligibility criteria:
inclusion criteria: * patient has signed and dated a study specific informed consent form approved by the reviewing institutional review board or ethics committee. * patient is 21 to 60 years of age. * patient is skeletally mature * patient requires a discectomy of one level from l2-s1. * patient has less than 50% loss of disc height at the affected level. * patient has persistent pain (predominantly leg pain, although some back pain that occurred at the same time as the leg pain and is believed to be associated with the disc herniation will not disqualify the patient from participating in this study) and symptoms despite a minimum of six weeks of non-operative treatment. * patient x-ray, ct or mr evidence of a herniated disc at the affected level. * patient has a minimum leg pain score of 6 cm on a 10 cm (i.e. 60 mm on a 100 mm) point visual analog scale (vas). * patient has a minimum oswestry disability index score of 40% (based upon a 100% scale). * patient is physically and mentally willing and able to comply with the postoperative scheduled clinical and radiographic evaluations and rehabilitation. exclusion criteria: * patient has had any previous surgery at the affected levels. * patient has had any attempt at spinal fusion, at any lumbar levels. * patient has motion of \< 3 degrees on pre-operative lateral flexion/extension radiographs * patient has a bmi * patient has severe osteoporosis of the spine. * patient has previously undergone chemotherapy, immunosuppressive therapy or radiation to the local area. * patient has active local or systemic infection. * patient has any known active malignancy. * patient has rheumatoid arthritis or systemic lupus erythematosus, or other chronic, inflammatory autoimmune disorder. * patient has ankylosing spondylitis or other spondyloarthropathy. * patient has spondylolisthesis. * patient is pregnant or plans to become pregnant during the course of the study. * patient has other concurrent physical or mental conditions that are likely to affect their outcome. * patient has congenital stenosis * patient is diabetic. * the patient has osteoporosis or severe osteopenia as determined by the investigator. females over 40 with bone density score less than -1. a clinical score calculator may also be utilized for females over 40 years of age. * patient has significant facet disease.

Keywords: intercushion