Nucleoplasty for Contained Herniated Lumbar Discs

Inclusion Criteria: * Mono radicular leg pain for at least 6 weeks as a result from a lumbar contained herniated disc. Leg pain must be of greater impact than concomitant back-pain * Failing conservative treatment; analgesics and/or physical therapy. Failing means persisting pain leading to problems with daily activities. * Magnetic resonance imaging (MRI): must be performed \< 6 weeks before start treatment. On MRI signs of contained herniated disc, maximum 33% obliteration of the spinal channel. No signs of other significant spine pathology (see exclusion criteria). * Neurological investigation by neurologist. Symptoms should be clinically related to the disc herniation level. * Age \>18 and \< 60 years * Mean leg pain on visual analogue scale (VAS) \>50 mm (0 -100) Exclusion Criteria: * Herniated disc with more than 33% obliteration of the spinal channel. * Annulus rupture with sequestrated herniated disc. * Pain on VAS below 50 mm * Pain existing longer than one year * Less than 50% preserved disc height * Conflict with social security/insurance. * Major motor impairment as a result of the herniation, paresis grade 3 or more using a Medical Research Council (MRC) score * Other degenerative causes of nerve root compression; ligament flavum or facet joint hypertrophy, degenerative spinal channel stenosis, loss of lumbar kyphosis, discopathy with signs of Schmorls' nodules and loss of nucleus pulposus signal. Other causes of radicular syndrome such as cancer, radiculitis or neural degeneration. * Spinal instability (spondylolisthesis, spinal fracture or tumor) * History of back surgery, chemonucleolysis or other intra discal procedures * Coagulopathies or oral anti-coagulation therapy * Infection * Pregnancy