Partial Disc Replacement with the PDN Prosthetic Disc Nucleus Device

Abstract

The aim of this study was to evaluate the efficacy of the PDN prosthetic disc nucleus device for the treatment of chronic discogenic back pain caused by degenerative disc disease. Among the 48 patients who underwent nucleus replacement surgery from January 2001 through May 2002, 46 patients were followed >6 months. The mean Oswestry Disability Index score was 58.9% preoperatively, and it improved to 18% at the 1-year follow-up. Visual Analogue Pain Scale scores improved from a preoperative mean of 8.5 to 3.1 after 1 year. The mean Prolo Scale score also improved from 5.2 preoperatively to 7.2 at 1 year. Major complications included four cases of device migration, requiring revision surgery, and infection in one patient. According to MacNab's criteria, results were excellent in 5 patients (10.9%), good in 31 (67.4%), fair in 3 (6.5%), and poor in 7 (15.1%). The overall clinical success rate was 78.3%. Nucleus replacement with the PDN device seemed to be effective in treating patients with chronic discogenic back pain caused by degenerative disc disease.

Design, synthesis, imaging, and biomechanics of a softness‐gradient hydrogel nucleus pulposus prosthesis in a canine lumbar spine model

“…These treatments consist of removal of the nucleus pulposus (nuclectomy) or the complete IVD (discectomy), with or without spinal fusion. Nuclectomy decreases the disc height and thereby changes the biomechanics of the IVD, explaining why long‐term surgical outcomes might not be as good as initially thought 9–14. Screws, cages, and connectors are often used to facilitate spinal fusion but do not restore the biomechanical function of the spine and may lead to nonunion, implant failure, and adjacent segment disease 15–22.…”

Evaluation of biocompatibility of a pectin/polyvinyl alcohol composite hydrogel as a new nucleus material

“…The hydrogel absorbs 80% of its weight in water, allowing it to restore disk height 5 . In 2003 Shim reported 46 cases with the clinical follow‐up; radiographically 19.6% showed device subsidence into the endplates, 60.9% scleroses at the endplates, and 82.8% increased Modic changes of the vertebral body in subsequent lumbar MRI films 6 . These events may be correlated with the mechanical character and shape of prothesis 7 .…”

Biomechanical assessment and fatigue characteristics of an articulating nucleus implant

“… 18 – 21 Unfortunately, a commonly reported complication has been extrusion of the device from the intradiscal space. 21 – 24 Various reasons for device extrusion have been demonstrated. These range from failure of the annular injury to heal, to the use of undersized devices, to fragmentation of the device itself.…”