The Use of Scrambler Therapy in Treating Chronic Pain Syndromes: A Systematic Review

BACKGROUND

Scrambler therapy (ST) is a noninvasive method of transcutaneous neuromodulation that has 510(K) clearance from the United States Food and Drug Administration for treating acute pain, postoperative pain, and intractable chronic pain. Since its inception, ST has been used to treat many chronic pain syndromes in a variety of patient populations. We synthesized the available literature for ST to delineate its overall evidence basis.

MATERIALS AND METHODS

We performed a systematic review based on conventional Preferred Reporting Items for Systematic Reviews and Meta-Analyses methods by surveying multiple data sources from January 1950 through October 2021. Two review authors, independently and in a standardized, unblinded fashion, conducted a systematic review to identify relevant studies and extract the necessary outcome measures. A conservative search strategy was implemented to identify all ST studies for the treatment of chronic pain syndromes. Primary outcome parameters collected were analgesic benefit, adverse effects, and other metrics such as sensorimotor testing.

RESULTS

A total of 21 studies met the final criteria for study inclusion and comprised randomized controlled trials (n = 8), prospective observational studies (n = 10), and retrospective cohort studies (n = 3). Nearly all the reported studies explored the use of ST for the treatment of neuropathic pain, with chemotherapy-induced peripheral neuropathy being the most studied condition. Most studies were limited by small cohorts but reported ST being safe, well tolerated, and providing clinically meaningful pain reduction. The duration of posttreatment follow-up ranged from ten to 14 days (concordant with completion of typical ST protocols) to three months. Secondary benefits such as medication reduction and improvement of sensory and motor symptoms were noted by some studies.

CONCLUSIONS

ST is regarded as a safe intervention with potential for significant analgesic benefit for neuropathic pain conditions. Although the available evidence is most robust for treating chemotherapy-induced peripheral neuropathy, ST has also been shown to be effective in treating other neuropathic pain syndromes. Evidence for ST use in nociceptive pain conditions is limited but appears promising. The favorable safety profile and increasing evidence basis for ST warrant more extensive recognition and consideration for use in clinical care.

Combination Intrathecal Drug Therapy Strategies for Pain Management

BACKGROUND

Numerous combination intrathecal drug therapy (CIDT) strategies exist and are utilized for varying pain syndromes, typically when monotherapy dose escalation or medication alternation is deemed untenable or unfeasible. Unfortunately, the supportive evidence basis for the use of these strategies and specific drug combinations is generally lacking and unclear, with many medications being used for off-label indications.

OBJECTIVE

In this manuscript, we provide a robust exploration and analysis of the literature to provide an evidence-based narrative for the use of CIDT strategies in regard to clinical indications, pharmacologic parameters, specific drug combinations, safety profiles, and future directions.

STUDY DESIGN

Narrative review.

METHODS

This was an evidence based narrative performed after extensive review of the literature.

RESULTS

Variances in intrathecal pharmacokinetics and pharmacodynamics are utilized advantageously with CIDT strategies to achieve improved analgesic benefit; however, appropriate use may be limited by increased or compounded risk of adverse effects. The supportive evidence for CIDT use for chronic pain conditions is largely lacking and limited to small, uncontrolled, observational studies, with many having various confounding factors, including a lack of standardized dosing. The most evidenced CIDT strategies include polyanalgesia with morphine-ziconotide, opioid-clonidine, and morphine-bupivacaine. Notably, in addition to pain relief, morphine-bupivacaine has been shown to decrease early opioid escalation requirements.

LIMITATIONS

The supportive evidence for CIDT use for chronic pain conditions is largely lacking and limited to small, uncontrolled, observational studies, with many having various confounding factors including a lack of standardized dosing.

CONCLUSIONS

CIDT strategies and polyanalgesia combinations can be effective for treating various patient populations with chronic pain. The appropriate use of these strategies may be limited by increased or compounded risk of adverse effects, both of which are highly patient and scenario dependent. Therefore, practitioners should maintain a particularly low threshold of suspicion for adverse effects in patients with CIDT such that safety profiles associated with this therapy can be favorably maintained.

Microfragmented Adipose Tissue With Adjuvant Platelet-Rich Plasma Combination Therapy for Partial-Thickness Supraspinatus Tear

A 50-year-old male presented with acute, sharp, right shoulder pain. Ultrasound of the right shoulder revealed a partial thickness tear of the supraspinatus. After conservative management failed to provide any relief, he was treated with microfragmented adipose tissue (MFAT) injection followed by platelet-rich plasma (PRP) at 14 weeks. At the 28-week follow-up, he showed significant improvement in pain and mobility with a resolution of the tear on ultrasound. While PRP has been shown to confer some protection against retears, very few studies have investigated the efficacy of MFAT use in rotator cuff pathology. In this case, we used a combination of MFAT and PRP to successfully treat a partial thickness supraspinatus tear. These agents may function in a synergistic manner, with MFAT providing a cell scaffold and PRP modulating the cellular environment to optimize healing. Further studies are needed to better understand the mechanism of this treatment modality in treating similar conditions.

Radiotherapy-Specific Chronic Pain Syndromes in the Cancer Population: An Evidence-Based Narrative Review

While radiation therapy is increasingly utilized in the treatment paradigm of many solid cancers, the chronic effects of radiation therapies are poorly characterized. Notably, understanding radiation-specific chronic pain syndromes is paramount given that the diagnosis and management of these conditions can serve to prevent long-standing functional impairments, optimize quality of life, and even allow for continued radiotherapy candidacy. These radiation-specific chronic pain phenomena include dermatitis, mucositis, enteritis, connective tissue fibrosis, lymphedema, and neuropathic pain syndromes. It is necessary to maintain a low threshold of suspicion for appropriately diagnosing these conditions as there exists a variance in when these symptoms arise after radiation. However, we present key epidemiological data delineating vulnerable cancer populations for each pain syndrome along with the available evidence for the management for each specific condition.

Dorsal Root Ganglion Stimulation for the Treatment of Non-Complex Regional Pain Syndrome Related Chronic Pain Syndromes: A Systematic Review

BACKGROUND

While the majority of indications and approvals for dorsal root ganglion stimulation (DRGS) are for the refractory management of complex regional pain syndrome (CRPS), emerging evidence has suggested that DRGS may be favorably used for a plethora of other chronic pain phenomena. Consequently, we aimed to characterize the use and efficacy of DRGS for these non-CRPS-related chronic pain syndromes.

MATERIALS AND METHODS

A systematic review of clinical studies demonstrating the use of DRGS for non-CRPS-related chronic pain syndromes. The literature search was performed using PubMed, Cochrane Library, and CINAHL plus across August and September 2020.

RESULTS

A total of 28 reports comprising 354 total patients were included in the analysis. Of the chronic pain syndromes presented, axial low back pain, chronic pelvic and groin pain, other peripheral neuropathies, and studies with multiple concomitant pain syndromes, a majority demonstrated >50% mean pain reduction at the time of last follow-up following DRGS. Physical function, quality of life (QOL), and lesser pain medication usage also were repeatedly reported to be significantly improved.

CONCLUSIONS

DRGS continues to lack supportive evidence from well designed, high level studies and recommendations from consensus committee experts. However, we present repeated and consistent evidence from lower level studies showing success with the use of DRGS for various non-CRPS chronic pain syndromes in reducing pain along with increasing function and QOL from one week to three years. Due to such low-level, high bias evidence, we strongly encourage the continuation of high-level studies in order to provide a stronger foundation for the use of DRGS in non-CRPS chronic pain patients. However, it may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis particularly if they manifest focal pain syndromes refractory to noninterventional measures and may not be ideal candidates for other forms of neuromodulation.

Modeling Commodity Flow in the Context of Invasive Species Spread: Study of Tuta absoluta in Nepal

Trade and transport of goods is widely accepted as a primary pathway for the introduction and dispersal of invasive species. However, understanding commodity flows remains a challenge owing to its complex nature, unavailability of quality data, and lack of systematic modeling methods. A robust network-based approach is proposed to model seasonal flow of agricultural produce and examine its role in pest spread. It is applied to study the spread of Tuta absoluta, a devastating pest of tomato in Nepal. Further, the long-term establishment potential of the pest and its economic impact on the country are assessed. Our analysis indicates that regional trade plays an important role in the spread of T. absoluta. The economic impact of this invasion could range from USD 17-25 million. The proposed approach is generic and particularly suited for data-poor scenarios.

Hydrodissection as a therapeutic and diagnostic modality in treating peroneal nerve compression

A 51-year-old man presented with pain in the region of his left patellar tendon and fibular head. He had previously undergone three L5 epidural steroid injections and physical therapy without relief. Prior magnetic resonance imaging was significant only for fat pad impingement, and electromyography and nerve conduction studies were negative. Ultrasound demonstrated an enlarged peroneal nerve suggestive of peroneal nerve entrapment. Three ultrasound-guided hydrodissection procedures offered symptomatic improvement and identified an area posterior to the fibular head that was unable to be hydrodissected, indicating scar tissue causing peroneal nerve compression. The patient was referred for peroneal nerve decompression at the area of entrapment with complete symptom relief. This case is unique in describing the ability of hydrodissection to identify nerve compression not visualized with other diagnostic tests.

Severe diarrhoea due to Cystoisospora belli in renal transplant patient on immunosuppressive drugs

Cystoisospora belli, formerly known as Isospora belli, protozoal parasite endemic to many regions of the world including the Caribbean, Central and South America, Africa, and South-East Asia. It is frequently encountered in patients with acquired immunodeficiency syndrome (AIDS) and is considered to be an AIDS-defining illness. Chronic severe watery diarrhoea due to C. belli has also been reported in other immunodeficiency states. C. belli infection in immunosuppressed patients has rarely been described. We describe severe diarrhoea due to C. belli in a human immunodeficiency virus-negative renal transplant recipient on immunosuppressive drugs. Oocysts of C. belli were detected in direct smear preparation of the diarrheic stool sample of the patient. The patient responded to combination treatment with Bactrim-double-strength (trimethoprim-sulfamethoxazole) and Nitazoxanide.

Strongyloides stercoralis hyperinfection in an immunocompetent patient with extreme eosinophilia

This report examines an unusual case of Srongyloides stercoralis hyperinfection in a 63-yr-old man. The patient had a history of vitamin B deficiency, on and off diarrhea, and clinical pellagra for a decade and a half. There was also evidence of extreme eosinophilia. The patient did not have any associated illness suggestive of immunosuppression. Treatment with ivermectin resulted in remarkable clinical improvement and reversion of eosinophil count to normal.

Human babesiosis--a case report

Babesiosis is an emerging, tick-transmitted, zoonotic disease caused by hematotropic parasites of the genus Babesia. Most cases of Babesial infections in humans have been acquired in temperate regions of the United States, Europe, France and England. A few cases of Babesiosis have been described in other parts of the world, including China, Taiwan, Egypt, South Africa, and Mexico.1,2 We report the first case of human Babesiosis, in a normosplenic, previously healthy individual from India.

Early diagnosis of filarial pleural effusion

This paper describes a case of pleural effusion due to filariasis. Microfilaria of Wucheraria bancrofti were detected in the pleural fluid on cytological examination. Treatment with diethylcarbamazine cleared the pleural effusion.

On combinatorial DNA word design

We consider the problem of designing DNA codes, namely sets of equi-length words over the alphabet [A, C, G, T] that satisfy certain combinatorial constraints. This problem is motivated by the task of reliably storing and retrieving information in synthetic DNA strands for use in DNA computing or as molecular bar codes in chemical libraries. The primary constraints that we consider, defined with respect to a parameter d, are as follows: for every pair of words w, x in a code, there are at least d mismatches between w and x if w not equal x and also between the reverse of w and the Watson-Crick complement of x. Extending classical results from coding theory, we present several upper and lower bounds on the maximum size of such DNA codes and give methods for constructing such codes. An additional constraint that is relevant to the design of DNA codes is that the free energies and enthalpies of the code words, and thus the melting temperatures, be similar. We describe dynamic programming algorithms that can (a) calculate the total number of words of length n whose free energy value, as approximated by a formula of Breslauer et al. (1986) falls in a given range, and (b) output a random such word. These algorithms are intended for use in heuristic algorithms for constructing DNA codes.

Discovery of association rules in medical data

Data mining is a technique for discovering useful information from large databases. This technique is currently being profitably used by a number of industries. A common approach for information discovery is to identify association rules which reveal relationships among different items. In this paper, we use this approach to analyse a large database containing medical-record data. Our aim is to obtain association rules indicating relationships between procedures performed on a patient and the reported diagnoses. Random sampling was used to obtain these association rules. After reviewing the basic concepts associated with data mining, we discuss our approach for identifying association rules and report on the rules generated.