International journal of spine surgery
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Current total disc replacement (TDR) for lumbar spine requires an anterior approach for implantation but presents inherent limitations, including risks to the abdominal structures, as well as resection of the anterior longitudinal ligament. By approaching the spine laterally, it is possible to preserve the stabilizing ligaments, which are a natural restraint to excessive rotations and translations, and thereby help to minimize facet stresses. This less invasive approach also offers a biomechanical advantage of placement of the device over the ring apophysis bilaterally; importantly, it also offers a greater opportunity for safer revision surgery, if necessary, by avoiding scarring of the anterior vasculature. We present the clinical and radiologic results of a lateral TDR device from a prospective single-center study. ⋯ The clinical and radiographic results of a laterally placed TDR have shown maintenance of pain relief and functional improvement over a long-term follow-up period. The benefits of the lateral access-minimal morbidity, avoidance of mobilization of the great vessels, preservation of the anterior longitudinal ligament, biomechanically stable orientation, and broader revision options-promote a new option for motion-preservation procedures.
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The biomechanical behavior of total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF) incomplex multiplanar motion is incompletely understood. The purpose of this study was to determine whether ACDF or TDR significantly affects in vitro kinematics through a range of complex, multiplanar motions. ⋯ This study compared multiplanar motion under load-displacement testing of subaxial cervical motion segments with and without implanted TDR and ACDF. We found a trend toward increased motion in adjacent levels in ACDF specimens compared with TDR specimens. Biomechanical multiplanar motion testing will be useful in the ongoing development and evaluation of spinal motion-preserving implants.
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Biomechanical studies have shown that dynamic stabilization restores the neutral zone and stabilizes the motion segment. Unfortunately, there are limitations to clinical measurement of lumbar motion segments when using routine radiographs. Radiostereometric analysis is a 3-dimensional technique and can measure the spinal motion segment more accurately than techniques using plain film radiographs. The purpose of this study was measure and compare the range of motion after dynamic stabilization, posterior lumbar fusion (PLF), and lumbar discectomy. ⋯ In this study a significantly lower amount of motion was seen after dynamic stabilization and PLF when compared with discectomy. A future study with a larger cohort is necessary to examine what effect, if any, these motions have on clinical outcomes.
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Fusion has long been used for treating chronic back pain unresponsive to nonoperative care. However, potential development of adjacent segment degeneration resulting in reoperation is a concern. Total disc replacement (TDR) has been proposed as a method for addressing back pain and preventing or reducing adjacent segment degeneration. The purpose of the study was to determine the reoperation rate at the segment adjacent to a level implanted with a lumbar TDR and to analyze the pre-TDR condition of the adjacent segment. ⋯ The 2.0% rate of adjacent segment degeneration resulting in reoperation in this study is similar to the 2.0% to 2.8% range in other studies and lower than the published rates of 7% to 18% after lumbar fusion. By carefully assessing the presence of pre-existing degenerative changes before performing arthroplasty, this rate may be reduced even more.
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Lumbar interbody fusion has long been used for the treatment of painful degenerative spinal conditions. The anterior approach is not feasible in some patients, and the posterior approach is associated with a risk of neural complications and possibly muscle injury. A trans-sacral technique was developed that allows access to the L5-S1 disc space. The purposes of this study were to investigate the clinical outcome of trans-sacral interbody fusion in a consecutive series of patients from 1 center and to perform a comprehensive review of the literature on this procedure. ⋯ The AxiaLIF approach allows access to the L5-S1 interspace without violating the annulus or longitudinal ligaments and with minimal risk to dorsal neural elements. It may be a viable alternative to other approaches to interbody fusion at the L5-S1 level. It is important that the patients be selected carefully and surgeons are familiar with the presacral anatomy and the surgical approach.