Case Report: Scrambler Therapy for Treatment-Resistant Central Neuropathic Pain in a Patient with Transverse Myelitis

Safety of Scrambler Therapy: A Systematic Review of Complications and Adverse Effects

OBJECTIVE

The objective was to qualitatively synthesize all reported cases of complications, adverse effects, side effects, or harms arising from the use of scrambler therapy (ST).

METHODS AND DESIGN

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The PubMed, Embase, Scopus, Web of Science, United States National Library of Medicine clinical trials registry, and Cochrane Central Register of Controlled Trials databases were searched from database inception to December 10, 2021. Case reports/series, abstracts, retrospective studies, and prospective studies (e.g., open-label trials, randomized controlled trials) pertaining to ST and any description of a complication, adverse effect, side effect, or harm were screened. The search protocol was developed a priori and registered via the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42021291838).

RESULTS

A total of six RCTs, 19 prospective open-label trials, and 11 case series / case reports met the inclusion criteria, comprising 1,152 total patients. Two patients experienced contact dermatitis, and one patient reported minor ecchymosis that resolved without intervention. This yielded a composite complication rate of 0.26% (3/1,152). There were zero reported serious adverse events.

CONCLUSIONS

When used in accordance with the treatment protocols described by the United States Food and Drug Administration and device manual, ST is associated with a reported composite complication rate that is orders of magnitude lower than those of invasive neuromodulation devices. ST neuromodulation is a safe alternative for patients who cannot undergo invasive neuromodulation device implantation because of either risk or preference.

Spinal cord stimulator for neuropathic pain in a patient with severe disability due to transverse myelitis

Transverse myelitis is an inflammatory disease of the central nervous system that disrupts nerve signals' conduction. The illness is characterised by weakness in the lower limbs accompanied by paresthesia and urinary and bowel incontinence. The most disabling sequel is the onset of chronic neuropathic pain, which can severely limit the patient's independence and negatively affect her quality of life. We present the case of a patient who received a spinal neurostimulator after a failure of conventional medical treatment. Masking pain through paresthesia, a mechanism provided by the device significantly reduces pain perception. The treatment success in our patient represents an advance in pain therapy.

Low-dose cannabinoid receptor 2 agonist induces microglial activation in a cancer pain-morphine tolerance rat model

AIMS

Cancer pain seriously affects the life quality of patients. Morphine is commonly used for cancer pain, but tolerance development limits its clinical administration. Central immune signaling is important in the development of cancer pain and morphine tolerance. Cannabinoid receptor 2 (CB2) inhibits cancer pain and morphine tolerance by regulating central immune signaling. In the present study, we investigated the mechanisms of central immune signaling involved in morphine tolerance inhibition by the CB2 agonist AM1241 in cancer pain treatment.

MAIN METHODS

Rats were implanted with tumor cells and divided into 4 groups: Vehicle (PBS), 0.07 μg AM1241, 0.03 μg AM1241, and AM630 (10 μg) + AM1241 (0.07 μg). All groups received morphine (20 μg/day, i.t.) for 8 days. AM630 (CB2 antagonist) was intrathecally injected 30 min before AM1241, and AM1241 was intrathecally injected 30 min before morphine. The spinal cord (SC) and dorsal root ganglion (DRG) were collected to determine the expression of Toll-like receptor 4 (TLR4), the p38 mitogen-activated protein kinase (MAPK), microglial markers, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α.

KEY FINDINGS

The expression of TLR4, p38 MAPK, microglial markers, IL-1β, and TNF-α was significantly higher in AM1241-pretreated groups than in the vehicle group (P < 0.05). No difference in microglial markers, IL-1β, and TNF-α expression was detected in the AM630 + AM1241 group compared with the vehicle group.

SIGNIFICANCE

Our results suggest that in a cancer pain-morphine tolerance model, an i.t. non-analgesic dose of AM1241 induces microglial activation and IL-1β TNF-α upregulation in SC and DRG via the CB2 receptor pathway.

Treatment of Déjerine-Roussy syndrome pain with scrambler therapy

Aim: Déjerine-Roussy syndrome or central thalamic pain can be devastating, and treatment with drugs and even deep brain stimulation can be unsatisfactory. Scrambler therapy is a form of neuromodulation that uses external skin electrodes to send a 'non-pain' signal to the brain, with some success in difficult-to-treat syndromes such as neuromyelitis optica spectrum disorder. We used scrambler therapy to treat a patient with 6 years of disabling Déjerine-Roussy syndrome pain. Methods: A 56-year-old man received multiple daily then monthly treatments with electrode pairs placed just above the area of distal pain. Each treatment was for 40 min. Results: His allodynia and hyperalgesia resolved within 10 min, and his pain score fell to almost zero after 30 min. Months later, he resumed normal activity and is off all his pain medications. No side effects were noted. Conclusion: Scrambler therapy appeared to reverse 6 years of disabling pain safely and economically, and continues to be effective. Further multi-institutional trials are warranted for this rare syndrome.

Scrambler therapy improves pain in neuromyelitis optica: A randomized controlled trial

OBJECTIVE

To determine whether Scrambler therapy is an effective, acceptable, and feasible treatment of persistent central neuropathic pain in patients with neuromyelitis optica spectrum disorder (NMOSD) and to explore the effect of Scrambler therapy on co-occurring symptoms.

METHODS

We conducted a randomized single-blind, sham-controlled trial in patients with NMOSD who have central neuropathic pain using Scrambler therapy for 10 consecutive weekdays. Pain severity, pain interference, anxiety, depression, and sleep disturbance were assessed at baseline, at the end of treatment, and at the 30- and 60-day follow-up.

RESULTS

Twenty-two patients (11 per arm) were enrolled in and completed this trial. The median baseline numeric rating scale (NRS) pain score decreased from 5.0 to 1.5 after 10 days of treatment with Scrambler therapy, whereas the median NRS score did not significantly decrease in the sham arm. Depression was also reduced in the treatment arm, and anxiety was decreased in a subset of patients who responded to treatment. These symptoms were not affected in the sham arm. The safety profiles were similar between groups.

CONCLUSIONS

Scrambler therapy is an effective, feasible, and safe intervention for central neuropathic pain in patients with NMOSD. Decreasing pain with Scrambler therapy may additionally improve depression and anxiety.

CLINICALTRIALSGOV IDENTIFIER

NCT03452176.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that Scrambler therapy significantly reduces pain in patients with NMOSD and persistent central neuropathic pain.