Reduced instantaneous center of rotation movement in patients with low back pain.

Purpose: The instantaneous center of rotation (ICR) can be used to investigate movement coordination and control in patients with low back pain (LBP). Tracking of the ICR in LBP patients has not been systematically investigated. This study aimed to (1) determine the within-session measurement error of ICR parameters, and (2) characterize the change in ICR among three groups of participants (no history of LBP = HC; history of LBP = HLBP; and current LBP = LBP).

Trunk Postural Muscle Timing Is Not Compromised In Low Back Pain Patients Clinically Diagnosed With Movement Coordination Impairments.

Trunk muscle timing impairment has been associated with nonspecific low back pain (NSLBP), but this finding has not been consistent. This study investigated trunk muscle timing in a subgroup of patients with NSLBP attributed to movement coordination impairment (MCI) and matched asymptomatic controls in response to a rapid arm-raising task. Twenty-one NSLBP subjects and 21 matched controls had arm motion and surface EMG data collected from seven bilateral trunk muscles.

Double and zero quantum filtered (2)H NMR analysis of D2O in intervertebral disc tissue.

The analysis of double and zero quantum filtered (2)H NMR spectra obtained from D2O perfused in the nucleus pulposus of human intervertebral disc tissue samples is reported. Fitting the spectra with a three-site model allows for residual quadrupolar couplings and T2 relaxation times to be measured. The analysis reveals changes in both the couplings and relaxation times as the tissue begins to show signs of degradation.

Nucleus implantation: the biomechanics of augmentation versus replacement with varying degrees of nucleotomy.

Nucleus pulposus replacement and augmentation has been proposed to restore disk mechanics in early stages of degeneration with the option of providing a minimally invasive procedure for pain relief to patients with an earlier stage of degeneration. The goal of this paper is to examine compressive stability of the intervertebral disk after either partial nucleus replacement or nuclear augmentation in the absence of denucleation. Thirteen human cadaver lumbar anterior column units were used to study the effects of denucleation and augmentation on the compressive mechanical behavior of the human intervertebral disk.

A comparison of the human lumbar intervertebral disc mechanical response to normal and impact loading conditions.

Thirty-four percent of U.S. Navy high speed craft (HSC) personnel suffer from lower back injury and low back pain, compared with 15 to 20% of the general population.

Fill of the nucleus cavity affects mechanical stability in compression, bending, and torsion of a spine segment, which has undergone nucleus replacement.

Study Design: Axial loading, rotation, and bending were applied to human cadaveric lumbar segments to investigate the changes in disc mechanics with denucleation and incremental delivery of a novel hydrogel nucleus replacement.

Objective: The purpose of this study was to investigate the effect of nucleus implant injection pressure/volume relationships on the quasi-static mechanical behavior of the human cadaveric lumbar intervertebral disc to determine if intact biomechanics could be reproduced with nucleus-implanted discs.

Summary Of Background Data: Previous studies have shown that volumetric filling of the nucleus cavity with a compliant nucleus replacement device will affect compressive stiffness of the implanted intervertebral disc, but data regarding restoration of mechanics through cavity pressurization are lacking.

Altered trunk motor planning in patients with nonspecific low back pain.

The authors investigated differences in trunk muscle activation timing between patients with chronic nonspecific low back pain (NSLBP) and asymptomatic controls during a self-initiated postural challenge. The authors compared 30 participants with NSLBP to 30 controls. Surface electromyographic data were collected from bilateral trunk muscles.

23Na TQF NMR imaging for the study of spinal disc tissue.

A method for acquiring triple quantum filtered (TQF) (23)Na NMR images is proposed that takes advantage of the differences in transverse relaxation rates of sodium to achieve positive intensity, PI, NMR signal. This PITQF imaging sequence has been used to obtain spatially resolved one-dimensional images as a function of the TQF creation time, tau, for two human spinal disc samples. From the images the different parts of the tissue, nucleus pulposus and annulus fibrosus, can be clearly distinguished based on their signal intensity and creation time profiles.

The application of 23Na double-quantum-filter (DQF) NMR spectroscopy for the study of spinal disc degeneration.

Degenerative disc disease is an irreversible process that leads to a loss of mechanical integrity and back pain in millions of people. In this report, (23)Na double-quantum-filtered (DQF) NMR spectroscopy is used to study disc tissues in two stages of degeneration. Initial results indicate that the (23)Na DQF signal may be useful for determining the degree of degeneration.

The role of the nucleus pulposus in neutral zone human lumbar intervertebral disc mechanics.

To study the effect of denucleation on the mechanical behavior of the human lumbar intervertebral disc through a 2mm incision, two groups of six human cadaver lumbar spinal units were tested in axial compression, axial rotation, lateral bending and flexion/extension after incremental steps of "partial" denucleation. Neutral zone, range of motion, stiffness, intradiscal pressure and energy dissipation were measured; the results showed that the contribution of the nucleus pulposus to the mechanical behavior of the intervertebral disc was more dominant through the neutral zone than at the farther limits of applied loads and moments.

2H double quantum filtered (DQF) NMR spectroscopy of the nucleus pulposus tissues of the intervertebral disc.

Deuterium (2H) double-quantum filtered (DQF) NMR spectroscopy of nucleus pulposus (NP) tissues from human intervertebral discs is reported. The DQF spectral intensities, DQ build-up rates, and DQF-detected rotating-frame spin-lattice relaxation times are sensitive to the degree of hydration of the NP tissue, and display a monotonous correlation with age between 15 and 80 years. The implications of this work are that the changes in water dynamics as detected via DQF NMR spectroscopy may be used as a probe of tissue degeneration in NP, particularly in the early stages of degeneration to which most standard NMR methods are not sensitive.