Bipolar spinal cord stimulation attenuates mechanical hypersensitivity at an intensity that activates a small portion of A-fiber afferents in spinal nerve-injured rats

Spinal Cord Stimulation Reduces Mechanical Hyperalgesia and Restores Physical Activity Levels in Animals with Noninflammatory Muscle Pain in a Frequency-Dependent Manner

“…Previous studies show mixed results on the duration of effects after a SCS treatment. Some studies show a cumulative and long-lasting (carryover) effect with repeated SCS, 67,68,81 while others show a more short-term effect that lasts for minutes or hours after SCS. 14,23,69,82,83 It is possible that the differences between studies relates to variables of stimulation.…”

“…However, motor threshold still only activates a small www.anesthesia-analgesia.org aNesthesia & aNalgesia portion of the Aβ-fiber pool fibers. 81 In neuropathic pain rats, 50 Hz SCS delivered at 55% motor threshold amplitude increased the withdrawal threshold from 3 to 20 g, but 50 Hz SCS delivered at 67% motor threshold increased the threshold to 82 g. 84 Moreover, the time to return to prestimulatory values ranged from 10 to 40 minutes depending on the intensity of stimulation with higher intensities, showing longer carryover effects. 84 Thus, greater intensities of stimulation produce greater analgesia that may result in a longer-lasting effect.…”

Effect of Spinal Cord Stimulation on Sensory Characteristics

“…A recent study with SCS treatment in rats after spinal nerve ligation, 24 suggested that attenuation of mechanical hypersensitivity is a gradual process and pointed to a possible 2-component mechanism of action: an immediate action and a longer lasting carry-over effect. Such a mechanism may serve to explain why we in our setting did not detect any significant changes in sensory characteristics.…”

Comparison of intensity‐dependent inhibition of spinal wide‐dynamic range neurons by dorsal column and peripheral nerve stimulation in a rat model of neuropathic pain

“…When pharmacological therapies fail to relieve chronic pain, or side effects associated with these therapies substantially impair quality of life, spinal cord stimulation (SCS) or peripheral nerve stimulation (PNS) are considered as alternative strategies for pain management (Long et al, 1981; Weiner, 2003; Kumar et al, 2008). SCS and PNS with parameters similar to those used in the clinic (e.g., 50–60 Hz, 0.2 ms) attenuate behavioural hypersensitivity to mechanical and thermal stimuli in nerve-injured rats (Maeda et al, 2008; Yang et al, 2011; Rosellini et al, 2012). In addition to initiating a feed forward inhibition of spinal nociceptive transmission (Melzack and Wall, 1965), synchronized electrical stimulation may also induce inhibitory postsynaptic potentials in dorsal horn neurons (Foreman et al, 1976; Narikawa et al, 2000), facilitate primary afferent depolarization to elicit presynaptic inhibition of incoming afferent inputs, activate descending pain modulation (Barchini et al, 2012; Song et al, 2013) and change afferent conduction properties (Campbell, 1981; Shechter et al, 2013).…”