Central nervous system stimulation therapies in phantom limb pain: a systematic review of clinical trials

The effectiveness of graded motor imagery and its components on phantom limb pain in amputated patients: A systematic review

BACKGROUND

Phantom limb pain (PLP) can be defined as pain in a missing part of the limb. It is reported in 50%-80% of people with amputation.

OBJECTIVES

To provide an overview of the effectiveness of graded motor imagery (GMI) and the techniques which form it on PLP in amputees.

STUDY DESIGN

Systematic review.

METHODS

Two authors independently selected relevant studies, screened the articles for methodological validity and risk of bias, and extracted the data. Inclusion criteria used were clinical studies, written in English or Spanish, using GMI, laterality recognition, motor imagery, mirror therapy, or a combination of some of them as an intervention in amputated patients, and one of the outcomes was PLP, and it was assessed using a validated scale. The databases used were PubMed, Scopus, Web of Science, CINAHL, and PEDro.

RESULTS

Fifteen studies were included in the review. After the intervention, all the groups in which the GMI or one of the techniques that comprise it was used showed decrease in PLP.

CONCLUSION

The 3 GMI techniques showed effectiveness in decreasing PLP in amputees, although it should be noted that the application of the GMI showed better results.

Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery

Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.

Transcranial magnetic stimulation in the treatment of phantom limb pain: a systematic review

BACKGROUND

 Phantom limb pain (PLP) occurs after amputations and can persist in a chronic and debilitating way. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation method capable of influencing brain function and modulating cortical excitability. Its effectiveness in treating chronic pain is promising.

OBJECTIVE

 To evaluate the evidence on the efficacy and safety of using rTMS in the treatment of PLP, observing the stimulation parameters used, side effects, and benefits of the therapy.

METHODS

 This is a systematic review of scientific articles published in national and international literature using electronic platforms.

RESULTS

 Two hundred and fifty two articles were identified. Two hundred and forty six publications were removed because they were duplicated or met the exclusion criteria. After selection, six studies were reviewed, those being two randomized clinical trials and four case reports. All evaluated studies indicated some degree of benefit of rTMS to relieve painful symptoms, even temporarily. Pain perception was lower at the end of treatment when compared to the period prior to the sessions and remained during patient follow-up. There was no standardization of the stimulation parameters used. There were no reports of serious adverse events. The effects of long-term therapy have not been evaluated.

CONCLUSION

 There are some benefits, even if temporary, in the use of rTMS to relieve painful symptoms in PLP. High-frequency stimulation at M1 demonstrated a significant analgesic effect. Given the potential that has been demonstrated, but limited by the paucity of high-quality studies, further controlled studies are needed to establish and standardize the clinical use of the method.

Symmetry Function: The Differences between Active and Non-Active Above-the-Knee Amputees

The number of patients with unilateral above-knee amputation (AKA) due to non-vascular causes has remained stable over the years, at 0.92 per 1000 people per year. Post-AKA individuals are at risk of experiencing a higher incidence of chronic pain. Post rehabilitation, it is estimated that between 16−62% of patients with musculoskeletal disabilities fail to meet the minimum criteria for physical activity in comparison to a healthy population. The current study included 14 participants (11 men and 3 women) with a mean age of 46.1 ± 14.2 years, body height of 1.76 ± 0.09 m, and weight of 79.6 ± 18.3 kg, who were all post-unilateral above-the-knee amputees. Patients in the study were divided into two groups: active (AC) and non-active (NAC). This study was conducted in a certified Laboratory of Biomechanical Analysis using the BTS Smart-E system (BTS Bioengineering). In order to investigate the symmetry function (SF) of gait, the only measurements included were the time series assessment of gait variables defining pelvic and lower limb joint motion and ground reaction forces (GRF). Both groups had an asymmetrical gait pattern with a different magnitude and relative position in the gait cycle, which was revealed by SF. The differences in terms of median, minimum, and maximum were statistically significant (p < 0.05), with SF ranging from −25 to 24% for the AC group and from 43 to 77% (59% on average) for the NAC group. The AC’s pattern was more symmetrical compared to the NAC’s pattern, especially in the case of pelvic and hip joint motion.

Overcoming clinical challenges of refractory neuropathic pain

INTRODUCTION

: Refractory neuropathic pain (ReNP), and its definition, is widely disputed amongst clinicians due in part to unclear categorical diagnosing guidelines, overall time duration of neuropathic pain, and the exhaustiveness of treatment options. Usually ReNP is defined as chronic, intractable, and unresponsive neuropathic pain that have otherwise been untreatable.

AREAS COVERED

: In this narrative review, we discuss and summarize the effectiveness of prospective ReNP research conducted over the past 10 years. This research looks at pharmacological and interventional therapies in clinical trial settings. The pharmacological therapies discussed include the use of adjuvant treatments to improve the safety and efficacy of conventional approaches. Different modalities of administration, such as injection therapy and intrathecal drug delivery systems, provide targeted drug delivery. Interventional therapies such as neuromodulation, pulse radiofrequency, and nerve lesioning are more invasive, however, they are increasingly utilized in the field, as reflected in ongoing clinical trials.

EXPERT OPINION

: Based on the current data from RCTs and systematic reviews, it is clear that single drug therapy cannot be effective and has significant limitations. Transitioning to interventional modalities that showed more promising results sooner rather than later may be even more cost-efficient than attempting different conservative treatments with a high failure rate.

Development and Validation of a Graded Motor Imagery Intervention for Phantom Limb Pain in Patients with Amputations (GraMI Protocol): A Delphi Study

BACKGROUND

Phantom limb pain can be defined as discomfort or pain in a missing part of the limb. The aims of this study were to develop and validate, through a Delphi methodology, a graded motor imagery protocol in order to reduce phantom limb pain.

METHOD

Physiotherapists and/or occupational therapists with experience in research and a minimum clinical experience of five years in the field of neurorehabilitation and/or pain were recruited by part of a group of experts to assess the intervention. The study was conducted through an online questionnaire, where experts assessed each aspect of the intervention through a Likert scale. As many rounds as necessary were carried out until consensus was reached among experts.

RESULTS

A total of two rounds were required to fully validate the intervention. During the second round, the relative interquartile range of all aspects to be assessed was less than 15%, thus showing a consensus among experts and with good concordance (Kappa index of 0.76).

CONCLUSION

Experts validated a graded motor imagery intervention of phantom limb pain in patients with amputations (GraMi protocol). This intervention can help to homogenize the use of graded motor imagery in future studies and in clinical practice.