Long-term outcome after implantation of prosthetic disc nucleus device (PDN) in lumbar disc disease

Hippokratia 2010; 14(3):176-184

P. Selviaridis, N. Foroglou, A. Tsitlakidis, A. Hatzisotiriou, I. Magras, I. Patsalas


Background: The prosthetic disc nucleus (PDN) device offers an adjunct treatment for patients with degenerative disc disease and herniation, who necessitate surgical intervention, avoiding total-disc replacement or fusion. This prospective, clinical study aimed to gauge the long-term effectiveness of microdiscectomy followed by PDN implantation in relieving pain and improving functional status in patients with symptomatic degenerative lumbar disc disease and herniation.
Methods: Ten patients with a) at least 6 months low back pain and/or sciatica resistant to conservative treatment and b) radiologically documented degenerative lumbar disc disease and herniation have been selected. Follow-up at 6 weeks, 3, 12, 48, and 96 months postoperatively included physical examination, radiological investigation (plain and dynamic radiographs and magnetic resonance imaging), and self-completion of outcome scales (visual analogue, Oswestry, and Prolo functional status). Short Form-36 version 2 Health Survey patient profile at 96 months completed the image of health related quality of life.
Results: Patients? mean follow-up was 100.6 months. Significant improvements in Oswestry, Prolo, and VAS scores were documented (p: 0.004 in all scales at 48 months). Generic health status was rated within the average lumbar disease population (46.3?6.8 for physical component summary and 45.2?9.6 for mental component summary). Lumbar spine range of motion (20.2?11.8 at 96 months) was restricted in relation to normal, but maintained considerable mobility. Treated disc height increased postoperatively (p:0.002) and its maintenance could also be documented in all cases. Disc height at the level above did not show any significant modification. All postoperative MRI showed a non-clinically significant high signal of end-plate on T2 sequences. Clinically relevant complications included one case of pulmonary thrombosis and one case of device extrusion, which was subsequently explanted.
Conclusions: After implantation, most patients continue to enjoy significant pain relief, a considerable amount of mobility is conserved and the disease specific functional outcome is excellent and remains for long, although it could not be supported that the generic health related quality of life is that of the general population.