Peripheral nerve field stimulation in the treatment of postlaminectomy syndrome after multilevel spinal surgeries.

INTRODUCTION: Chronic low back pain in patients with postlaminectomy syndrome (PLS) is challenging to treat, especially for patients who have undergone multilevel surgical procedures. Despite conservative therapy and available interventional pain procedures including spinal cord stimulation (SCS) and intrathecal therapies, patients may continue with intractable low back pain. Peripheral nerve field stimulation (PNFS) may represent an effective alternative treatment option for these patients when conventional treatments do not provide adequate relief of intractable low back pain. METHODS: Eighteen patients underwent an uneventful PNFS trial with percutaneous placement of four temporary quadripolar leads (Medtronic, Inc., Minneapolis, MN, USA) placed subcutaneously over the lumbar or thoraco-lumbar area. RESULTS: After experiencing excellent pain relief over the next two days, temporary leads were removed. The patients were implanted with permanent leads and rechargeable or non-rechargeable generator two to four weeks after temporary lead removal. All patients reported sustained pain relief 12 months after implantation. DISCUSSION: PNFS with use of four vertically orientated leads provides an effective treatment option for patients with PLS after multilevel surgical procedures with intractable low back pain who have failed conservative treatment. PNFS may provide pain relief with advantages over conservative treatments and interventional treatments including SCS and intrathecal therapy. CONCLUSION: PNFS may be more effective in treating intractable low back pain than SCS in patients with PLS after multilevel spinal surgeries.

Spinal cord stimulation as alternative treatment for chronic post-herniorrhaphy pain.

OBJECTIVE: Our goal was to determine the efficacy of spinal cord stimulation for patients with intractable post-herniorrhaphy pain which conventional treatment failed to ameliorate. PROCEDURE: The patients underwent an uneventful spinal cord stimulator (SCS) trial with percutaneous placement of two eight-electrode epidural leads (Medtronic Inc, Minneapolis, MN, USA) to level T7-T8-T9. RESULTS: Upon experiencing excellent pain relief over the next two days during the trial, the patients were implanted with permanent leads and rechargeable or non-rechargeable generators two to four weeks later and reported sustained pain relief during following 12 months after implantation. CONCLUSION: We conclude that SCS offers an alternative treatment option for intractable post-herniorrhaphy pain. This type of treatment should be considered for use in a select group of patients when all conventional treatments failed.

Functional reactivity of cerebral capillaries.

The spatiotemporal evolution of cerebral microcirculatory adjustments to functional brain stimulation is the fundamental determinant of the functional specificity of hemodynamically weighted neuroimaging signals. Very little data, however, exist on the functional reactivity of capillaries, the vessels most proximal to the activated neuronal population. Here, we used two-photon laser scanning microscopy, in combination with intracranial electrophysiology and intravital video microscopy, to explore the changes in cortical hemodynamics, at the level of individual capillaries, in response to steady-state forepaw stimulation in an anesthetized rodent model. Overall, the microcirculatory response to functional stimulation was characterized by a pronounced decrease in vascular transit times (20%+/-8%), a dilatation of the capillary bed (10.9%+/-1.2%), and significant increases in red blood cell speed (33.0%+/-7.7%) and flux (19.5%+/-6.2%). Capillaries dilated more than the medium-caliber vessels, indicating a decreased heterogeneity in vessel volumes and increased blood flow-carrying capacity during neuronal activation relative to baseline. Capillary dilatation accounted for an estimated approximately 18% of the total change in the focal cerebral blood volume. In support of a capacity for focal redistribution of microvascular flow and volume, significant, though less frequent, local stimulation-induced decreases in capillary volume and erythrocyte speed and flux also occurred. The present findings provide further evidence of a strong functional reactivity of cerebral capillaries and underscore the importance of changes in the capillary geometry in the hemodynamic response to neuronal activation.