PubMed · 15951951
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Alvaro Sanabria. 2005. Randomized controlled trial.. https://doi.org/10.1007/s00268-005-1100-z
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BACKGROUND AND OBJECTIVE: We recently demonstrated that intrathecal bupivacaine before or after acute photochemical spinal injury improved functional outcome in rats. However, the closest model to spinal trauma is the contusive weight-drop method. The aim of this study was to evaluate functional, electrophysiological and anatomical consequences of a contusive spinal-cord lesion in rats with or without an intrathecal injection of bupivacaine. METHODS: Fifteen minutes before a contusive spinal lesion, 18 rats received intrathecally either 0.5% bupivacaine (Group T) or saline (Group C). During an 18-days period, motor and sensory functions were evaluated, and bladder voiding dysfunction was noted. Somatosensory evoked potential testings were performed at day 18. Then, the intact spinal cord area at the epicentre of the lesion and the extent of the lesion were measured. RESULTS: Motor deficit was less and inclined-plane stability was better in treated animals at all times, the scores were statistically different from day 7. There were no differences concerning the sensory test. Despite no significant difference, there were less spinal bladders in the T group from day 7. Somatosensory evoked potential latencies were longer in T group, but only the first negative component (N1) was statistically significant. Amplitudes were higher in T group, but were not statistically different. The spinal cord intact area at the epicentre of the lesion was higher in the T group (1.23 +/- 0.8 mm(2) vs. 0.81 +/- 0.39 mm(2); P < 0.05). The extent of the lesion was higher in the C group (9.4 +/- 2.9 mm vs. 6.4 +/- 3.4 mm; P < 0.05). CONCLUSION: Intrathecal 0.5% bupivacaine provide a neuroprotective effect by decreasing functional, electrophysiological and anatomical consequences after a contusive spinal cord injury.
OBJECTIVE: Effects of angulation of computed tomography (CT) reconstruction plane on sacroiliac (SI) joint morphology were studied, and factors influencing the approach to fluoroscopically guided SI joint injection were assessed. DESIGN AND PATIENTS: CT scans of pelvises were reformatted on 41 subjects, aged 51.7 (+/-15.1) years. Transverse images were reconstructed at the caudal 3 cm of the SI joint tilting plane of reconstruction from -30 degrees to +30 degrees at 15 degrees increments. Anteroposterior diameter of joint (depth), angle from sagittal plane (orientation angle), and distance from skin were measured. Joint contour was classified, and presence of bone blocking access to the joint was recorded. Comparison between angles were analysed by t-test. Relationships between variables were assessed by a Pearson correlation test. RESULTS: Depth was shorter with angulation in the inferior direction (P<0.01). Orientation angle increased with superior angulation (P<0.01). Distance from skin increased (P<0.01) with angulation in either direction. Joint contour was significantly different from baseline at each angle (P<0.001) but highly variable. Inferior angulation resulted in interposition of ilium between skin and SI joint, and superior angulation caused bone block due to the lower sacrum. None of these features was identified without tilting of the reconstruction plane, and effects were more pronounced with steeper angulation. CONCLUSION: Angulation of the reconstruction plane considerably affects the appearance of the sacroiliac joints. By shortening joint depth, an inferiorly directed approach to SI joint injection may make fluoroscopic guidance easier, although associated bony interposition can prevent access to the synovial compartment. A superiorly directed approach is more likely to have adverse effects.
Orexins (hypocretins) are peptides of hypothalamic origin that play an important role in maintaining wakefulness. Reduced orexin levels have been associated with an increased incidence of narcolepsy. Considering thalamic nuclei are interconnected with virtually all neocortical regions and the thalamus has been found to produce distinct activities related to different levels of arousal, we have examined the actions of orexins on thalamic neurons using an in vitro thalamic slice preparation. The orexins (orexin-A and orexin-B) produced distinct actions within different intralaminar nuclei. Orexin-B strongly depolarized the majority of centrolateral nucleus (CL) neurons (71%), but depolarized a significantly smaller population of parafascicular nuclei (Pf) neurons (10%). In the mediodorsal thalamic nucleus (MD), orexin-B depolarized 21% of the neurons tested. Overall, orexin-B was found to be more potent than Orexin-A. Orexin-A depolarized a significantly smaller population of CL neurons (23%), but had no effect on Pf neurons. In addition, orexin-A produced a small depolarization in 28% of neurons in the thalamic reticular nucleus (TRN). Both orexin-A and orexin-B had no effect on neurons in the lateral posterior (LP), lateralodorsal (LD), posterior thalamic (Po), ventrobasal (VB) nucleus and lateral geniculate nucleus (LGN). The depolarizing actions of orexins were sufficient to alter the firing mode of these neurons from a burst- to tonic-firing mode. The excitatory actions of orexin-B result from a decrease in the apparent leak potassium current (Kleak). The orexin-B mediated excitation was also attenuated by bupivacaine suggesting the involvement of Kleak current. Further, the actions of orexin-B were occluded by the classical neurotransmitter dopamine, indicating the orexins may share similar ionic mechanisms. Thus, the depolarizing actions of orexins may play a key role in altering the firing mode of thalamic neurons associated with different states of consciousness.