Diskogemic low back pain – the pathogenesis and disk rescue with Dynafix system.

A Ribas 1, 2 , J Ruttermann 2, R Oertmüller 2.
Spine Research Center , Clinica Santa Lucia, Rio de Janeiro, Brazil 1
Zenturm für pathologie, Institut für Anatomie, Berlin, Deutschland 2

APLAR, 1-5 August 2006, Kuala Lumpur, Malaysia

Introduction Diskogenic low back pain (DLBP) is a complex entity and its pathogenesis remains unclear. Nerve ingrowth deeper into lumbar painful disks had been reported. The mechanobiology of the lumbar disk play an important role in this issue. We propose that mechanical treatment with the Dynafix System can promote pain resolution and disk regeneration, when the conservative treatment failed.

Material and method  Sixty four patients underwent surgery  for treatment of diskogenic low back pain , were the conservative treatment for more than eight  months failed , using the Dynafix System. 20 specimens of abnormal disks and 20 normal disks were collected  during the procedure,  posterior lumbar arthroplasty, to investigate the morphologic features and innervations containing neurofilament( NF200 ) and neuropeptides substance P ( SP )  and  vasoactive-intestinal peptide ( VIP ) immunoreactive nerve fibers.

Results  The morphologic characteristic of the painful disk was the formation of the strip zone of vascularized granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus in which there was several fissures. The innervation of SP, NF and VIP immunoreactive nerve fibers in the painful disks was more extensive compared with the control disks. The nerve  ingrowth  deep into annulus fibrosus and nucleus pulposus was observed mainly along the strip zone of granulation tissue in the painful disks. Pain resolution was observed in  84,06 % of the patients and  the serial MRI demonstrated disk regeneration after 8 to 12 months after surgery., those  under 50 years old.

Conclusions Findings indicate that the strip zone of granulation tissue with extensive innervations along the tears in the posterior part of the painful disk  may be the structures involved in discogenic pain  and are mechanodpendent. Disk rescue is possible acting in the mechanobiology , removing the abnormal loading factors. The arthroplasty with the Dynafix System  proved  to be effective.