[Implantation of the ProDisc intervertebral disk prosthesis for the lumbar spine].

OBJECTIVE

To eradicate treatment-resistant lower back pain caused by painful degeneration of the intervertebral disks. To avoid the disadvantages of alternative fusion surgery, especially degenerative wear and tear on adjacent segments, by maintaining the mobility of the affected motion segments.

INDICATIONS

Treatment-resistant lower back pain due to painful degeneration of the intervertebral disks ("degenerative disk disease").

CONTRAINDICATIONS

Spondylolisthesis, scoliosis, osteoporosis, infection, spinal stenosis, degeneration of the vertebral articulations.

SURGICAL TECHNIQUE

The intervertebral disk is excised through an anterior approach. It is essential to retain good mobility of the motion segment, if necessary, by resection of the posterior longitudinal ligament. After revitalization of the vertebral base and cover plates and chiseling of a groove for the keel of the prosthesis, the upper and lower prosthetic plates are inserted and the polyethylene inlay is locked into place.

RESULTS

From April 2002 to May 2004, 36 ProDisc (Synthes Spine, West Chester, PA, USA) modular intervertebral disk prostheses were implanted in 34 patients (26 women, eight men, average age 44.3 years). Clinical evaluation was based on the visual analog scale (VAS), the Oswestry Disability Index (ODI), and the SF-36 Questionnaire. Follow-up assessment also included radiographic views of the lumbar spine in two planes in flexion and extension and standing. The follow-up interval for all patients was at least 1 year and 2 years for 14 patients. 26 patients were very satisfied with the operation, five patients were satisfied, and three patients were less satisfied. The clinical parameters recorded on the VAS, ODI and SF-36 improved from 7.4 to 2.8 (VAS), 48.0 to 13.1 (ODI) and 31.3 to 44.2 (SF-36, Physical Component Summary Score) from the time of the preoperative assessment to the 1-year follow-up. The range of motion at the segment with the implanted prosthesis was 10 degrees on average at L4/5 and 7 degrees on average at L5/S1 1 year postoperatively.