Clinical Trial: Autonomic Function Testing and Spinal Cord Stimulation in Chronic Visceral Pain
Study Status: Terminated
Recruit Status: Terminated
Study Type: Interventional
Official Title: Autonomic Function Testing and Spinal Cord Stimulation: Implications for Successful Therapy in Chronic Visceral Pain
Brief Summary: The purpose of this study is to assess the effect of the spinal cord stimulator (A small wire is surgically implanted under the skin. Low-level electrical signals are then transmitted through the lead to the spinal cord to alleviate pain. Using a magnetic remote control, the patients can turn the current on and off, or adjust the intensity.) on the autonomic nervous system (sympathetic and parasympathetic). Some studies support that the spinal cord stimulation suppresses or decreases sympathetic outflow (the sympathetic nervous system is the one that provide us with the "flight and fight response" and the parasympathetic nervous system is the one that works while we "sleep, rest and digest".). The sympathetic nervous system is important in blood pressure regulation also. However, there are not reports regarding the effect of the spinal cord stimulation on blood pressure regulation in chronic visceral pain patients. Most clinical trials are focus on the effect of the spinal cord stimulation on pain relief. We think we could use blood pressure, heart rate and special analysis of these signals and their relationship to other pain measurements to assess the effect of the spinal cord stimulation in an objective way.
Detailed Summary: Spinal Cord Stimulation (SCS) has been used since 1967 for the treatment of pain: complex regional pain syndromes 1 , ischemic limb pain 2-5, failed back surgery syndrome 6, 7, and refractory angina pectoris 8-11. Recently, Kapural et al. reported a case series of six patients that underwent SCS for the treatment of chronic visceral pain (CVP)12, 13. SCS reduced 50% of the patients' pain and improved patient functionality by 60% 14 . Animal studies suggested that dorsal column pathways are involved in the transmission of visceral pain 12, 13. Clinical studies in patients with visceral cancer have shown that interruption of the fibers of the dorsal columns that ascend close to the midline of the spinal cord significantly relieves pain and decreases analgesic requirement 15-18. Different studies support the hypothesis that visceral pain perception is positively modulated by the descending pathways from the medulla. Dorsal column lesion leads to a reduction of thalamic activation by visceral stimuli and decreased visceral pain perception 19. Visceral innervation occurs via sympathetic and parasympathetic pathways; parasympathetic afferents enter the vagal afferents carrying nociceptive information enter trunks while sympathetic afferents carrying nociceptive information enter at the levels T6 and L3. Therefore, limited case series using SCS for CVP suggested that pain relief was achieved by blocking these segments suppressing sympathetic outflow to the abdomen and pelvis 14. The relationship between autonomic nervous system (ANS) and pain are poorly understood. Animal and clinical research has provided evidence for close interaction between pain modulatory systems and the ANS 20, 21. However, little is known about the ANS function in chronic pain patients. Our previous funded work suggested that chronic low back pain (CLBP) patients have reduced LFRRI (not increased as expected) and that indices of the vagal component of the HRV (RMSSD, HFRRI) were also attenuated. The
Sponsor: Vanderbilt University
Current Primary Outcome: MSNA [ Time Frame: Before and after spinal cord stimulator implant ]
Original Primary Outcome: Same as current
Current Secondary Outcome: Heart rate and blood pressure [ Time Frame: Before and after spinal cord stimulator ]
Original Secondary Outcome: Same as current
Information By: Vanderbilt University
Dates:
Date Received: May 8, 2008
Date Started: February 2008
Date Completion: February 2009
Last Updated: September 23, 2010
Last Verified: September 2010
