The spine journal : official journal of the North American Spine Society
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Polyethylene (PE) has been used in total disc replacements (TDRs) in Europe since the 1980s. However, the extent of surface damage of PE, including rim fracture and wear, after long-term implantation remains poorly understood. ⋯ This is the first study to quantitatively analyze the long-term PE damage mechanisms in contemporary TDRs. The TDRs displayed surface damage observed previously in both hip and knee replacements. Because of the evidence of increasing wear with implantation time, along with the demonstrated potential for osteolysis in the spine, regular long-term follow-up for patients undergoing TDRs is warranted.
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Clinical Trial
Incidence of simultaneous epidural and vascular injection during lumbosacral transforaminal epidural injections.
The incidence of vascular penetration during contrast confirmed fluoroscopically guided transforaminal lumbosacral epidural injections has been reported as 8.9% to 21.3% depending on the level of injection. Recently, intermittent fluoroscopy was shown to miss more than half of the vascular injections observed under live fluoroscopy. The number of misses increased when epidural and vascular contrast flow appeared simultaneously, even if the fluoroscopic image was taken during contrast injection. To date, no studies have documented the incidence of simultaneous epidural and vascular contrast injections. Also, most previous studies of vascular injections did not document use of live fluoroscopy during contrast injection, so the incidence of vascular injections may be higher than reported. ⋯ Simultaneous epidural and vascular injection is twice as likely to occur as vascular injection alone. Use of intermittent fluoroscopy can miss the transient appearance of the vascular component of these injections, giving the false impression of successful contrast placement. In light of these results, live fluoroscopy is recommended during contrast injection for confirmation of lumbosacral transforaminal epidural injections.
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INFUSE has been proven effective in conjunction with threaded cages and bone dowels for single-level anterior lumbar interbody fusion (ALIF). The published experience with posterolateral fusion, although encouraging, utilizes a significantly higher dose and concentration of recombinant human bone morphogenic protein-2 (rhBMP-2) and a different carrier than the commercially available INFUSE. ⋯ Posterolateral spine fusion involves a more difficult healing environment with a limited surface for healing, a gap between transverse processes and the milieu of distractive forces. Historically, only ICBG has been able to overcome these challenges and reliably generate a successful posterolateral lumbar spine fusion. In contrast to prior studies, clinically available INFUSE delivers only 12 mg rhBMP-2 at a concentration of 1.5 mg/mL. Despite the lower dose and concentration of rhBMP-2, this study suggests that fusion success with INFUSE is equivalent to ICBG for posterolateral spine fusion. As with ICBG, development of solid fusion or nonunion is a multifactorial process. The use of INFUSE is not a substitute for proper surgical technique or optimization of patient-related risk factors. Additional studies are needed to determine the incremental benefit of a greater rhBMP-2 dose or use of alternative carriers for posterolateral fusion. Finally, correlation between radiographic findings and clinical outcomes, and a cost-benefit analysis are needed. Despite these issues, this study presents compelling evidence that commercially available INFUSE is an effective ICBG substitute for one- and two-level posterolateral instrumented spine fusion.
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Comparative Study
The validity of manual examination in assessing patients with neck pain.
Although manual therapists believe that they can diagnose symptomatic joints in the neck by manual examination, that conviction is based on only one study. That study claimed that manual examination of the neck had 100% sensitivity and 100% specificity for diagnosing painful zygapophyseal joints. However, the study indicated that its results should be reproduced before they could be generalized. ⋯ The present study found manual examination of the cervical spine to lack validity for the diagnosis of cervical zygapophyseal joint pain. It refutes the conclusion of the one previous study. The paradoxical lack of statistical difference between the two studies is accounted for by the small sample size of the previous study.
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Current imaging techniques used to evaluate fusion status after a posterolateral fusion such as radiographs, computed axial tomography (CT) scans, and tomograms are known to be inaccurate, with error rates estimated from 20% to 40%. Previous studies evaluated CT scans using 2-4-mm thick slices with limited reconstructions. ⋯ Fine-cut CT scans with reconstructions have a considerably greater degree of interobserver and intraobserver agreement compared with flexion/extension and anteroposterior radiographs. Observers agree most often when the fusion is assessed as solid. Fusion evaluation based on radiographs agrees with CT scans only half the time. Future studies are needed to correlate the findings on fine-cut CT scans with surgical exploration.