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INTRODUCTION: The decision for selecting patients for surgical treatment of metastatic spinal cord compression (MSCC) is challenging even for experienced surgeons. Recently, the spinal instability neoplastic score (SINS) has been proposed to help surgeons in the evaluation of spinal stability in the setting of spinal metastases. This study aimed to evaluate the correlation between SINS and preoperative visual analog scale (VAS), as well as the pre- and post-operative association of the VAS and neurological function. METHODS: A prospective cohort study was conducted in a tertiary referral cancer center. Seventy-nine patients with MSCC were surgically treated from June 2012 to March 2015. Pain status before and after surgery was assessed using VAS score, and neurological status was evaluated using the American Spine Injury Association Impairment Scale (AIS) before and after surgery. Pain was classified as VAS (0-4) none or mild pain; VAS (5-8) moderate pain; and VAS (9-10) as severe pain. Neurological function was scored as AIS A: Complete deficits, AIS B-D: Incomplete deficits, AIS E: Neurologically intact. SINS degrees were classified as 0-6-stable; 7-12 potentially unstable, and 13-18-unstable. Spearman's correlation coefficient test was utilized for correlation between pain and SINS; Chi-square association test was utilized for evaluating pre- and post-operative pain and AIS, as well as the association between SINS and tumor types. RESULTS: A higher SINS correlates with severe mechanical pain preoperatively (ρ = 0.38, P = 0.001); surgical procedure improved neurological function (P = 0.0001), and decrease pain (P = 0.84). Finally, a higher SINS was also associated with osteolytic tumors (P = 0.03). CONCLUSIONS: The SINS correlates with mechanical pain. Surgery provides a significant improvement in pain and neurological status, especially in patients who presented higher SINS scores and some degree of preoperative neurological function.
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Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.