The beneficial effect of spinal cord stimulation in a patient with severe cerebral ischemia and upper extremity ischemic pain

Neuromodulation: What the neurointerventionalist needs to know

Neuromodulation is the alteration of neural activity in the central, peripheral, or autonomic nervous systems. Consequently, this term lends itself to a variety of organ systems including but not limited to the cardiac, nervous, and even gastrointestinal systems. In this review, we provide a primer on neuromodulation, examining the various technological systems employed and neurological disorders targeted with this technology. Ultimately, we undergo a historical analysis of the field's development, pivotal discoveries and inventions gearing this review to neuro-adjacent subspecialties with a specific focus on neurointerventionalists.

Spinal cord stimulation to achieve wound healing in a primary lower limb critical ischaemia referral centre

Critical lower limb ischaemia is a diffuse pathology that could cause claudication, severe ischaemic pain and tissue loss. The common treatment includes modification of risk factors, pharmacological therapy and endovascular or surgical revascularisation of the lower limb to restore a pulsatile flow distally. Spinal cord stimulator is seen as a valid alternative in patients unsuitable for revascularisation after endovascular or surgical revascularisation failure and as adjuvant therapy in the presence of a functioning bypass in patients with extensive tissue loss and gangrene presenting a slow and difficult wound healing. We report our experience on spinal cord stimulation (SCS) indication and implantation in patients with critical lower limb ischaemia, at a high-volume centre for the treatment of peripheral arterial disease.

Effects of electrical cervical spinal cord stimulation on cerebral blood perfusion, cerebrospinal fluid catecholamine levels, and oxidative stress in comatose patients

OBJECTIVES

Electrical spinal cord stimulation (SCS) is used to treat of chronic pain, obstructive arterial-related ischemia, and anginal pain. This study investigated cerebral blood perfusion, cerebrospinal fluid (CSF) catecholamine levels, and oxidative stress before and after cervical SCS in comatose patients.

METHODS

We evaluated cerebral blood perfusion, catecholamine (dopamine, norepinephrine, and epinephrine) levels, and oxidative stress in 20 comatose patients before and after SCS. After SCS for six months, cerebral blood perfusion (SPECT index, 2.293 +/- 0.255 vs. 2.779 +/- 0.209, p < 0.001), dopamine (49.0 +/- 12.1 vs. 198.9 +/- 62.6, p = 0.025), and norepinephrine (197.6 +/- 62.9 vs. 379.6 +/- 52.6, p = 0.021) but not epinephrine were significantly increased. Moreover, superoxide free radicals in whole blood were significantly decreased (210,079 +/- 47,763 vs. 109,212 +/- 20,086, p = 0.011) after SCS. Nine patients recovered from the consciousness within 71-287 days.

CONCLUSIONS

Increase of cerebral blood perfusion and catecholamines (dopamine and norepinephrine) in CSF after SCS was observed, whereas epinephrine level was unchanged. The superoxide free radicals were decreased after SCS. The results suggest that SCS increases cerebral blood perfusion, attenuates oxidative stress and increases biogenic amines in comatose patients.

Roles of dorsal column pathway and transient receptor potential vanilloid type 1 in augmentation of cerebral blood flow by upper cervical spinal cord stimulation in rats

Clinical and basic studies have indicated that upper cervical spinal cord stimulation (cSCS) significantly increases cerebral blood flow (CBF), but the mechanisms are incompletely understood. This investigation was conducted to differentiate between stimulation of dorsal column fibers and upper cervical spinal cord cell bodies in cSCS-induced increases in CBF and decreases in cerebrovascular resistance (CVR). cSCS (50 Hz, 0.2 ms, 1 min) was applied on the left C1-C2 dorsal column of pentobarbital anesthetized, ventilated and paralyzed male rats. Laser Doppler flowmetry probes were placed bilaterally over the parietal cortex, and arterial pressure was monitored. cSCS at 30%, 60%, and 90% of motor threshold (MT) produced vasodilation bilaterally in cerebral cortices. Subsequently, cSCS was applied at 90% MT, and ipsilateral responses were recorded. Ibotenic acid (0.3 mg/ml, 0.1 ml) placed on dorsal surface of C1-C2 (n=7) to suppress cell body activity, did not affect cSCS-induced %DeltaCBF (42.5+/-8.1% vs. 36.8+/-7.1%, P>0.05) and %DeltaCVR (-19.4+/-4.2% vs. -15.2+/-5.6%, P>0.05). However, bilateral transection of the dorsal column at rostral C1 (n=8) abolished cSCS-induced changes in CBF and CVR. Also, rostral C1 transection (n=7) abolished cSCS-induced changes in CBF and CVR. Resinferatoxin (RTX), an ultrapotent transient receptor potential vanilloid type 1 (TRPV1) agonist, was used to inactivate TRPV1 containing nerve fibers/cell bodies. RTX (2 microg/ml, 0.1 ml) placed on the C1-C2 spinal cord (n=7) did not affect cSCS-induced %DeltaCBF (60.2+/-8.1% vs. 46.3+/-7.7%, P>0.05) and %DeltaCVR (-25.5+/-3.5% vs. -21.4+/-8.9%, P>0.05). However, i.v. RTX (2 microg/kg, n=9) decreased cSCS-induced %DeltaCBF from 65.0+/-9.5% to 27.4+/-7.2% (P<0.05) and %DeltaCVR from -28.0+/-7.6% to -14.8+/-4.2% (P<0.05). These results indicated that cSCS-increases in CBF and decreases in CVR occurred via rostral spinal dorsal column fibers and did not depend upon C1-C2 cell bodies. Also, our results suggested that cerebral but not spinal TRPV1 was involved in cSCS-induced cerebral vasodilation.