The study aims at assessing the short and long-term effectiveness and patient perception of benefit with the use of a DIAM™ Spinal Stabilization System in the treatment of complex disc disease at a single level from L2 to L5.

This study is a multi-center, prospective, randomized, controlled trial. Patients will be randomized in 2 groups:

Investigational group: a single level herniectomy procedure, followed by placement of the DIAMTM Spinal Stabilization System; Control group: a single level herniectomy procedure; After surgery, patients will be followed for a 2 years period with required follow up visits at 6 weeks, 3 months, 6 months, 1 year, 2 years and 4 years (optional visit).

Inclusion Criteria:

• Has a history of sciatica (radicular pain) for at least 6 weeks, but not more than 1 year secondary to one symptomatic lumbar disc herniation at the levels L2-L5 as confirmed by patient history and clinical evaluation, and without major neurological impairment (i.e. not less than M 3/5; Medical Research Council Classification);
• Has a history of continuous low back pain for no more than 1 year secondary to lumbar degenerative disc disease (intermittent back pain may occur for more than a year);
• Has pre-treatment back pain score greater than or equal to 3, concomitant with leg pain score greater than or equal to 6. Leg pain score must be greater than back pain score (pain intensity score measured on a 10 cm VAS scale);
• Has one symptomatic disc herniation: protrusion, extrusion or sequestration (Milette & Fardon, 2001) as confirmed by MRI at the target level;
• Evidence of disc degeneration ≤ Grade IV at the target and adjacent levels as confirmed by MRI (Pfirrmann, 2001);
• Has an Oswestry Disability Index (ODI) score ≥ 34%;
• Has been treated non-operatively (e.g. bed rest, physical therapy, medications, TENS, manipulation, hydrotherapy, acupressure/acupuncture, massage, bracing and/or spinal injections) for at least 6 continuous weeks unless strong clinical grounds for expediting surgery;
• Patient male or female, age 20-60 years inclusive and is skeletally mature;
• Is willing and able to comply with the study plan and able to provide an informed consent;

Exclusion Criteria:

• Has a primary diagnosis of spinal disorder other than degenerative disc at the involved level;
• Has a symptomatic disc herniation at more than one lumbar level;
• Requires a herniectomy at more than one lumbar level;
• Has a disc degeneration at the treated and adjacent levels > Grade IV (Pfirrmann, 2001);
• Has a decrease of disc height ≥ 30% as measured by the center of the disc space, and compared to the disc space at the next superior spinal level;
• Has Modic changes on MRI greater than Grade I at the target level;
• Has Modic changes on MRI at the adjacent levels;
• Has an advanced degree of retrolisthesis as shown by lateral X-rays (> 25%, i.e. grade I as per Meyerding);
• Has a clinical evidence of lysis, antero listhesis or scoliosis (Cobb angle more than 10°);
• Has signs of segmental instability: more than 4 mm of translation or more than 10° angular motion between adjacent end plates (comparing flexion and extension views);
• Has congenital or iatrogenic posterior element insufficiency (e.g. facet resection, spondylolysis, pars fracture, or Spinal Bifida Occulta);
• Has had any previous lumbar spine surgery;
• Has a Waddell signs of inorganic behaviour score greater than or equal to 3;
• Has evidence of an active disruptive psychiatric disorder, cognitive impairment or other known condition, significant enough to impact the perception of pain, precludes surgical procedure, clinical evaluation and/or ability to evaluate treatment outcome as determined by investigator;
• Has a known allergy to silicone, polyethylene, or titanium;
• Is an alcohol and /or drug abuser, as defined by currently undergoing treatment for alcohol and/or drug abuse;
• Has obesity defined by BMI greater than or equal to 35;
• Inability to complete the questionnaires;
• Planned pregnancy during the course of the study;
• Previous enrollment into a spine study;
• Vulnerable patients or unable to exercise free informed consent;