Refractory Central Neurogenic Pain in Spinal Cord Injury Case Presentation Edwin B. George, MD, PhD Wayne State University John D. Dingell VAMC 2012
Disclosures This continuing education activity is managed and accredited by Professional Education Service Group. The information presented in this activity represents the opinion of the author(s) or faculty. Neither PESG, nor any accrediting organization endorses any commercial products displayed or mentioned in conjunction with this activity. No Commercial support was received for this activity.
Disclosures Edwin B. George, MD, PhD Consultant: Medtronics Inc Consultant: Merz Pharmaceuticals Consultant, Speaker: Teva Pharmaceuticals CME Staff Disclosures Professional Education Services Group staff have no financial interest or relationships to disclose
Learning Objectives At the conclusion of this activity, the participant will be able to do the following: Discuss the presentation of neurogenic pain in a case of Spinal Cord Injury Describe the role of pharmacological agents including narcotic pain medications, agents acting on central pain centers including tricyclics and SNRI s, and modulators of neural firing including gaba-ergic agents and other anticonvulsants Explain the advantages of implanted electrical stimulators
Case Presentation A 49-year-old white male suffered a spinal cord injury in a motor vehicle accident Tetraparesis with central cord syndrome, with most of the damage being at C3/C4 Approximately 9 months after his injury he developed increasing pain involving all four limbs, which had a burning quality and was excruciating
Nociceptive vs Neuropathic Pain Transmission of noxious stimuli from periphery to CNS Usually aching or throbbing Responds well to NSAIDs and opiods Injury to nervous system causes abnormal neuronal firing patterns Often burning, shooting or paraesthetic Often limited response to analgesics
Case Presentation Gabapentin 800 mg q 6 hours and doxepin 25 mg q HS initially used for pain, failed gabapentin was later increased to 1200 mg TID Doxepin was replaced with amitriptyline not tolerated due to sedation Tramadol, propxyphene, oxycodone SA, fentanyl patch, morphine each failed to control his pain
Case Presentation Duloxetine was tried in place of tricyclics Tolerated but pain still uncontrolled Pregabalin was tried in place of gabapentin some partial benefit Trial of intrathecal morphine did not provide any relief
Oral Medications for Neuropathic Pain Anticonvulsants Gabapentin and pregabalin block calcium channels Others block sodium channels Tricyclics and SNRIs Block re-uptake of norepinephrine and 5HT* Opioids Bind opioid receptors* *Tramadol
Case Presentation A dorsal column stimulator was rejected given his high cervical cord injury Deep brain stimulation (DBS) surgery was performed electrodes bilaterally in the periventricular gray zone electrodes bilaterally in the ventral caudal nucleus of the thalamus adequate pain control was eventually achieved
Electrical Modulation of Pain Pathways Three potential sites for intervention Dorsal columns Sensory thalamus* Periventricular (periaqueductal) gray matter* Avoids sedation and systemic side-effects Requires surgery for electrode implantation, battery (IPG) replacement Requires programming the implanted pulse generator (IPG), limits MRI *off-label use for DBS
Spinal cord stimulation versus conventional medical management for neuropathic pain Randomised 100 failed-back surgery syndrome patients with predominant leg pain of neuropathic radicular origin Therapy at least 6 months, all patients were followed up to 1 year ITT analysis at 6 months: 24 SCS patients (48%) and 4 CMM patients (9%) (p < 0.001) achieved the primary outcome of achieving 50% or more pain relief The SCS group experienced improved leg and back pain relief, quality of life, and functional capacity, as well as greater treatment satisfaction (p 0.05 for all comparisons) K. Kumar et al. / Pain 132 (2007) 179 188
Spinal cord stimulation versus conventional medical management for neuropathic pain 25%
Deep brain stimulation for pain relief: A meta-analysis MEDLINE (1966 to February 2003) and EMBASE (1980 to January 2003) searched using key words deep brain stimulation, sensory thalamus, periventricular gray and pain Six studies (between 1977 1997) identified The long-term pain alleviation rate was highest with DBS of the PVG/PAG (79%), or the PVG/PAG plus sensory thalamus/internal capsule (87%). Stimulation of the sensory thalamus alone was less effective (58% long-term success) (p < 0.05) Journal of Clinical Neuroscience (2005) 12: 515 519
Deep brain stimulation for pain relief: A meta-analysis Journal of Clinical Neuroscience (2005) 12: 515 519
Complications of Deep Brain Stimulation: A Collective Review
Thank-you! Questions?
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