The cervical facet joint and its capsule are a common source of neck pain from whiplash. Mechanical hyperalgesia elicited by painful facet joint distraction is associated with spinal neuronal hyperexcitability that can be induced by transmitter/receptor systems that potentiate the synaptic activation of neurons. This study investigated the temporal response of a glutamate receptor and transporters in the dorsal root ganglia (DRG) and spinal cord. Bilateral C6/C7 facet joint distractions were imposed in the rat either to produce behavioral sensitivity or without inducing any sensitivity. Neuronal metabotropic glutamate receptor-5 (mGluR5) and protein kinase C-epsilon (PKCε) expression in the DRG and spinal cord were evaluated on days 1 and 7. Spinal expression of a glutamate transporter, excitatory amino acid carrier 1 (EAAC1), was also quantified at both time points. Painful distraction produced immediate behavioral hypersensitivity that was sustained for 7 days. Increased expression of mGluR5 and PKCε in the DRG was not evident until day 7 and only following painful distraction; this increase was observed in small-diameter neurons. Only painful facet joint distraction produced a significant increase (p<0.001) in neuronal mGluR5 over time, and this increase also was significantly elevated (p ≤ 0.05) over responses in the other groups at day 7. However, there were no differences in spinal PKCε expression on either day or between groups. Spinal EAAC1 expression was significantly increased (p<0.03) only in the nonpainful groups on day 7. Results from this study suggest spinal glutamatergic plasticity is selectively modulated in association with facet-mediated pain.
Whole body vibration (WBV) has been linked to neck and back pain, but the biomechanical and physiological mechanisms responsible for its development and maintenance are unknown. A rodent model of WBV was developed in which rats were exposed to different WBV paradigms, either daily for 7 consecutive days (repeated WBV) or two single exposures at Day 0 and 7 (intermittent WBV). Each WBV session lasted for 30 min and was imposed at a frequency of 15 Hz and RMS platform acceleration of 0.56 AE 0.07 g. Changes in the withdrawal response of the forepaw and hind paw were measured, and were used to characterize the onset and maintenance of behavioral sensitivity. Accelerations and displacements of the rat and deformations in the cervical and lumbar spines were measured during WBV to provide mechanical context for the exposures. A decrease in withdrawal threshold was induced at 1 day after the first exposure in both the hind paw and forepaw. Repeated WBV exhibited a sustained reduction in withdrawal threshold in both paws and intermittent WBV induced a sustained response only in the forepaw. Cervical deformations were significantly elevated which may explain the more robust forepaw response. Findings suggest that a WBV exposure leads to behavioral sensitivity. Keywords: whole body vibration; spine; pain; injury Several epidemiological studies have linked exposure to whole body vibration (WBV) with neck and back pain, [1][2][3][4] suggesting that vibration can lead to the onset of both pain syndromes. American male workers operating vibrating vehicles, such as industrial trucks and tractors, have been reported to have a higher prevalence of low back pain and are three-times more susceptible to acute herniated lumbar discs than workers whose occupations do not involve such exposures.3,5 Also, military helicopter aviators report increased pain during deployment compared to their pre-deployment reports of pain, with between 22-37% reporting neck and 39-70% reporting low back pain. 4 Further, the frequency of pain was significantly higher for aviators who experienced substantially increased flight hours during deployment compared to those who did not, 4 suggesting that the amount of exposure to WBV may affect the pain. 4 Despite the strong suggestive evidence of these epidemiological studies that pain can develop from WBV and may be influenced by the nature and frequency of the exposure, there is still little known about how these factors relate to the onset, maintenance, and resolution of pain.A limited number of studies have defined the biomechanical response to vibration and related resonance and vibration frequency to physiological responses known to be involved in pain-related injuries. The resonant frequency of the seated human undergoing vertical vibration has been reported to be 4.5 Hz from a series of studies using accelerometers on the first and third lumbar vertebrae (L1, L3) and the sacrum of volunteers exposed to vertical vibrations, ranging in frequencies from 2 to 15 Hz. 6 A later study using similarl...
Implantation of a ProDisc-C does not significantly modify the kinematics and facet pressure at the index level in cadaveric specimens during lateral bending and axial torsion. However, changes in facet contact pressures after disc arthroplasty may have long-term effects on spinal loading and cartilage degeneration and should be monitored in vivo.
Lymphoceles are a well-known complication of renal transplant surgery and can be asymptomatic or present with a variety of symptoms and complications. We describe a patient who presented with a Pasteurella multocida infection of a lymphocele which occurred 3 weeks after a course of penicillin for a cat bite and 10 months after a renal transplant nephrectomy. We also will review the incidence, predisposing factors, origin, symptomatology, diagnosis, complications, and treatments of post-renal transplant lymphoceles.
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