Motion-preserving technologies for degenerative lumbar spine: The past, present, and future horizons

Abstract

Over the past few decades, remarkable advancements in the understanding of the origin of low-back pain and lumbar spinal disorders have been achieved. Spinal fusion is generally considered the “gold standard” in the treatment of low-back pain; however, fusion is also associated with accelerated degeneration of adjacent levels. Spinal arthroplasty and dynamic stabilization technologies, as well as the continuous improvement in diagnosis and surgical interventions, have opened a new era of treatment options. Recent advancements in nonfusion technologies such as motion-preservation devices and posterior dynamic stabilization may change the gold standard. These devices are designed with the intent to provide stabilization and eliminate pain while preserving motion of the functional spinal unit. The adaption of nonfusion technologies by the surgical community and payers for the treatment of degenerative spinal conditions will depend on the long-term clinical outcome of controlled randomized clinical studies. Although the development of nonfusion technology has just started and the adoption is very slow, it may be considered a viable option for motion preservation in coming years. This review article provides technical and surgical views from the past and from the present, as well as a glance at the future endeavors and challenges in instrumentation development for lumbar spinal disorders.© 2011 SAS - The International Society for the Advancement of Spine Surgery. Published by Elsevier Inc. All rights reserved.

Numerical analysis of the influence of nucleus pulposus removal on the biomechanical behavior of a lumbar motion segment

“…Therefore, care must be taken for the spine patients as to whether they are fit for it. But at present time, who could benefit from nucleus replacement is uncertain (Serhan et al 2011). To determine what kind of patients could benefit from nucleus replacement, we investigated the influence of NP removal on the biomechanical behavior of a lumbar motion segment using finite element method and explored the potential therapeutic strategies for spine patients.…”

“…Nucleus replacement preserves the biomechanics of the annulus fibrosus (AF) and cartilaginous endplate (Di Martino et al 2005;Strange et al 2010) and allows retention of disc biomechanical properties (Meakin andHukins 2001, Yao et al 2006). However, nucleus replacement complications may result in poor disc kinematics which can cause neural impingements, joint facet degenerations or bone fractures (Serhan et al 2011). Therefore, care must be taken for the spine patients as to whether they are fit for it.…”

In vitro oxidative degradation of a spinal posterior dynamic stabilization device

“…[1][2][3] Many problems, such as adjacent segment degeneration and pseudarthrosis, are associated with spinal fusion and to alleviate these problems non-fusion techniques have been developed. 4 The BDyn device (S14 Implants, Pessac, France) is a posterior dynamic stabilization (PDS) device that provides an alternative to spinal fusion. This non-fusion device comprises a mobile titanium alloy rod, a fixed titanium alloy rod, a polycarbonate urethane (PCU) ring and a silicone cushion ( Figure 1).…”

A photopolymerized composite hydrogel and surgical implanting tool for a nucleus pulposus replacement

“…However, up to date, all implantation attempts with a NP replacement material have failed due to extrusion, expulsion or subsidence of the implanted material [13,14]. The required material properties have been subject of controversial discussions over the last two decades.…”

“…What is clear, is that a material needs to be implanted in a minimally invasive manner to avoid damaging existing tissue [15]. It also needs to re-establish disc height without destroying the endplate [12,16] and should not extrude when the spinal segment is cyclically loaded [13,18]. We propose an implant solution based on a photopolymerizable material.…”