Recent advances in understanding and managing phantom limb pain

Effectiveness of mirror therapy on management of phantom limb pain and adjustment to limitation among prosthetic users; A single blinded randomized controlled trial

OBJECTIVE

To determine the effectiveness of conventional physical therapy with and without mirror therapy on phantom limb pain and improving adjustment to limitation among prosthetic users.

DESIGN

Single blinded Randomized controlled trial.

SETTING

University of Lahore Teaching Hospital (UOLTH), Lahore.

SUBJECTS

Study enrolled 36 unilateral lower limb amputees diagnosed with PLP with pain intensity of minimum 3 on Numeric Rating Scale (NRS).

INTERVENTIONS

Participants received treatment based on the level of amputation and respective assessment. Group A received four weeks of mirror therapy followed by routine physical therapy while Group B received routine physical therapy only including strengthening, stretching, isometric exercise.

MAIN MEASURES

Severity of Phantom limb Pain was measured with Numeric Rating Scale (NRS) while The Trinity Amputation and Prosthesis Experience Scale (TAPES) assessed the limitation in daily life. Measurements were taken at baseline, at the end of 2nd and 4th week.

RESULTS

Among total, 18 patients received mirror therapy along with routine physical therapy and 18 received routine physical therapy alone. The mean (S.D) age of participants in Group-I was 35.22 ± 6.33 while in Group-II was 36.33 ± 6.30.At baseline, both groups (experimental and control group) were comparable for both NPRS (6.17 ± 1.80 and 6.33 ± 1.74) and Adjustment to limitation on TAPES scale (12.78 ± 4.36 and 11.72 ± 3.69). MT along with routine physical therapy significantly reduced the intensity of PLP at the end of 4th week (2.27 ± 1.17 and 4 ± 1.37). While on TAPES observable changes were recorded in Adjustment to limitation (19.67 ± 2.54 and 16.00 ± 3.97).

CONCLUSION

Mirror Therapy as an additional approach along with routine physical therapy over four weeks was more effective than conventional therapy only in managing severity of PLP and significantly improved adjustment to limitation.

Efficacy of repetitive transcranial magnetic stimulation for phantom limb pain- a meta analysis of randomized controlled trials

INTRODUCTION

Phantom limb pain (PLP) is a neuropathic syndrome experienced by the majority of amputees. Various treatment options are available for amputees suffering from PLP including pharmacological, psychological and neuromodulation techniques. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique that has proven its efficacy in alleviating PLP. Hence, we aimed to conduct a meta-analysis to evaluate the effectiveness of rTMS in improving pain in patients with PLP.

METHODS

Literature search was carried out on 5 electronic databases from the inception of the paper till 13th August, 2024. Randomized Controlled Trials evaluating the efficacy of rTMS in patients with PLP against a control group were included in our study. The Visual Analogue Scoring (VAS) system was used to evaluate the severity of pain. Quality assessment was performed with the Cochrane bias assessment tool and data was pooled on Review manager using the Mantel-Haenszel Random-effects model.

RESULTS

5 RCTs included in this paper were included and consisted of 140 participants experiencing PLP. There was a significant reduction in pain score in the rTMS group at the end of treatment when compared to the control group (P = 0.00001). A drop out sensitivity analysis significantly improved the results by reducing the heterogeneity to null (P = 0.00001). After 30 days of treatment, there was a significant difference of pain score from baseline in rTMS groups.

CONCLUSION

Our meta-analysis demonstrates the role of rTMS in significantly reducing VAS score in patients with PLP. In the future, larger clinical trials are required that evaluate the long-term efficacy profile of rTMS to establish it as a mainstay of therapy in patients with PLP.

Phantom limb experience after brachial plexus anaesthesia

There are more than two million amputees in the USA, and almost all will experience phantom limb sensations (PLS), describing the missing limb as still present. They may also experience intense pain, known as phantom limb pain (PLP), a considerable factor in poor quality of life. In some upper extremity amputees and following brachial plexus avulsion injury (BPAI), hand digits can be detected and mapped to distinct facial skin areas, termed hand-to-face remapping. In this study, we analysed PLS following brachial plexus anaesthesia (BPA) administered prior to upper limb surgeries. Our 39 participants had planned shoulder, wrist or hand surgery. We sought to determine the time course for the emergence of phantom limb experiences after BPA up to the following 24 hours in participants with intact limbs. We also investigated whether there was hand-to-face remapping, suggesting potential cortical reorganization, or changes in proprioception before and after the induction of BPA. Twenty (54%) participants reported PLS immediately after the onset of BPA (T2), and 28 (72%) participants altered proprioception (AP) after surgery (T3). However, neither PLP nor hand mapping onto the face was reported or evoked. PLS were seen earlier than AP. We conclude that PLS arise rapidly after BPA-induced temporary deafferentation of the upper limb and might serve as a model for the permanent deafferentation experienced in individuals with a major upper limb amputation or BPAI. These results contribute to defining a time course for changes after BPA and increase our understanding of how phantom limb phenomena might arise following limb amputation or BPAI.

Examining heterogeneity and reporting of mirror therapy intervention for phantom limb pain: A scoping review

BACKGROUND

Mirror therapy shows promise in the treatment of phantom limb pain but lacks robust evidence.

OBJECTIVES

To address this gap, we conducted a scoping review aiming to comprehensively explore the landscape of mirror therapy practice, gather details about the session content, and offer recommendations for future research.

METHOD

We searched seven databases for published work from 1995 to May 2023. Two independent reviewers selected, assessed, and extracted data from eligible articles. Articles, regardless of study design, were considered eligible if they investigated mirror therapy as an intervention for phantom limb pain.

RESULTS

A total of 44 articles were included, comprising 16 randomized control trials, 14 prospective cohort studies, 15 case reports, and 3 protocols. These studies collectively involved 942 patients, with male patients representing 70 % of the participants. Lower limb amputation, primarily attributed to trauma, accounted for 88 % of the included patients. Pain intensity was predominantly assessed by a visual analog scale (61 %). However, there was a notable absence of detailed descriptions regarding mirror therapy sessions, particularly concerning the number of exercises, duration per exercise, and repetitions. Typically, sessions lasted 15 min each, conducted once daily. The exercises primarily focused on motor exercises targeting the distal part of the limb.

CONCLUSION

The practice of mirror therapy was characterized by poor description, showed significant heterogeneity, and a lack of standardized protocols, which contributes to an overall low level of evidence. Addressing these gaps in practice description and standardization is crucial for improving reproducibility and strengthening the evidence base for the prescription of mirror therapy.

Cryoneurolysis for phantom limb pain: a systematic review

AIMS

Phantom limb pain (PLP) is a painful sensation occurring in patients around the site of an amputation. The aim of this systematic review is to evaluate the efficacy of cryoneurolysis in the management of phantom limb pain.

MATERIALS AND METHODS

A systematic review was performed according to the PRISMA 2020 guidelines. An initial search yielded 200 articles from four major scientific databases (PubMed, Embase, Cochrane Library, WebOfScience). Five articles met inclusion criteria, four of which underwent additional pooled statistical analysis.

RESULTS

Pooled analysis of the included trials revealed a cumulative Cohen's d effect size of 1.55 (95% CI [0.24, 2.87]; p = 0.02; z = 2.32) for the reduction of pain on a 10-point pain scale following cryoneurolysis intervention. The remaining article that did not meet inclusion criteria for statistical analysis was a case report that reported a reduction in pain from 9/10 to 1/10 one week following intervention.

CONCLUSIONS

The large effect size demonstrated a statistically and clinically significant improvement in patient-reported pain. Additionally, patients may be able to reduce their amount of pharmaceutical pain management with successful cryoneurolysis treatment. However, these findings are limited by the small sample size and high heterogeneity between studies. Further high-quality studies should be performed to corroborate these findings.

PROTOCOL REGISTRATION

www.crd.york.ac.uk/prospero identifier is CRD42024543085.

Insights into optimizing phantom pain management: A human-centered approach to end-user perspectives

BACKGROUND

This report explores and summarizes perspectives from end users on unmet needs in achieving optimal and effective phantom pain management through a human-centered design approach.

OBJECTIVE

To examine current strategies, pharmacological, nonpharmacological, surgical procedures, virtual reality, and mirror therapy, and the evidence supporting them, in the management of phantom limb pain.

DESIGN

This study reviewed and analyzed transcripts acquired in nonresearch contexts from the Veterans Affairs Translational Education and Mentoring Center's commercialization training program and from a Veteran Engagement Panel. Key themes were extracted using quasi-qualitative analysis of one-on-one interviews.

RESULTS

Clinicians and patients report that early patient intervention and education will yield improved management of phantom limb pain, which aligns with the growing recognition of the impact of patient-centered care on overall treatment outcomes. Mirror therapy is viewed as an effective and low-risk therapy, though compliance and buy-in may be barriers to clinical practice. Patient engagement can contribute to better treatment adherence and outcomes.

CONCLUSION

The study highlights implementation barriers, importance of end-user input, and the role of the Veteran Engagement Panel in providing feedback to pain researchers. The findings help explain unaddressed challenges and areas requiring further research to direct phantom pain management.

Case Report: Reduction in post-amputation phantom limb pain intensity accompanying the onset of phantom limb telescoping

Introduction

Individuals with limb loss frequently report post-amputation phenomena, including nonpainful phantom sensations, phantom limb pain (PLP), and residual limb pain (RLP). Although post-amputation pain is common, not all patients benefit from widely accepted treatments. A greater understanding of phantom limb "telescoping", the experience of one's phantom hand or foot gradually approaching the residual limb, may assist in developing more effective interventions for reducing post-amputation pain. This case report explores the relationships between PLP, RLP, telescoping, and psychosocial experience in one person with a lower limb amputation. The aim of this case is to illustrate one possible relationship between telescoping and PLP as the mechanisms linking the two remain equivocal.

Methods

The participant is a 35-year-old male who underwent a transfemoral amputation due to a traumatic injury to his right leg approximately 4 years prior. He responded to questionnaires evaluating demographic and health-related information (e.g., age, sex, marital status, reason for amputation), pain and psychological variables via the Brief Pain Inventory (BPI-SF), ID Pain Questionnaire (IDPQ), Pain Catastrophizing Scale (PSC-4), Patient Health Questionnaire-4 (PHQ-4), Life Orientation Test-Revised (LOT-R), Connor-Davidson Resilience Scale (CD-RISC2), and Chronic Pain Acceptance Questionnaire (CPAQ-8) and telescoping, measured by a newly developed app. The participant completed a semi-structured interview that was designed to ascertain patterns in the overlapping experience of phantom limb telescoping and post-amputation pain.

Results

The participant rated his average PLP as 10 on a Numeric Rating Scale (NRS) from 0 ("no pain") to 10 ("worst pain imaginable") shortly after amputation. Approximately 12 months later, the participant noticed a shortening of his phantom limb, with a concurrent decrease in PLP. At present, his average NRS pain intensity is a 5/10. The participant described how the daily, debilitating PLP intensity diminished to weekly, manageable pain over time. Most notably, his responses on questionnaires were consistent with neuropathic PLP, mild to moderate levels of pain interference, a high level of catastrophic thinking about pain, low optimism, and mild symptoms of anxiety and depression.

Discussion

In this report, telescoping appeared to be preceded by an initial reduction in PLP intensity but these findings are based on a single case report and must be replicated with a large sample size before we have a clearer idea of the relationship between telescoping and PLP. This study provides insight into factors that may maintain PLP, generating targets for further investigation.

A Computational Framework for Understanding the Impact of Prior Experiences on Pain Perception and Neuropathic Pain

Pain perception is influenced not only by sensory input from afferent neurons but also by cognitive factors such as prior expectations. It has been suggested that overly precise priors may be a key contributing factor to chronic pain states such as neuropathic pain. However, it remains an open question how overly precise priors in favor of pain might arise. Here, we first verify that a Bayesian approach can describe how statistical integration of prior expectations and sensory input results in pain phenomena such as placebo hypoalgesia, nocebo hyperalgesia, chronic pain, and spontaneous neuropathic pain. Our results indicate that the value of the prior, which is determined by the internal model parameters, may be a key contributor to these phenomena. Next, we apply a hierarchical Bayesian approach to update the parameters of the internal model based on the difference between the predicted and the perceived pain, to reflect that people integrate prior experiences in their future expectations. In contrast with simpler approaches, this hierarchical model structure is able to show for placebo hypoalgesia and nocebo hyperalgesia how these phenomena can arise from prior experiences in the form of a classical conditioning procedure. We also demonstrate the phenomenon of offset analgesia, in which a disproportionally large pain decrease is obtained following a minor reduction in noxious stimulus intensity. Finally, we turn to simulations of neuropathic pain, where our hierarchical model corroborates that persistent non-neuropathic pain is a risk factor for developing neuropathic pain following denervation, and additionally offers an interesting prediction that complete absence of informative painful experiences could be a similar risk factor. Taken together, these results provide insight to how prior experiences may contribute to pain perception, in both experimental and neuropathic pain, which in turn might be informative for improving strategies of pain prevention and relief.

Targeted muscle reinnervation in upper extremity amputations

PURPOSE

Targeted muscle reinnervation (TMR) is a relatively recent surgical innovation that involves the coaptation of major peripheral nerves to a recipient motor branch that innervates an expendable muscle target. The original indication for TMR was augmentation and optimization of myoelectric signals in the amputated limb for use of myoelectric prosthetics. Incidentally, surgeons and patients discovered that the technique also could treat and prevent phantom and residual limb pain. TMR is performed at the time of amputation or delayed any time after the amputation, and TMR can also be performed at any level of amputation. In the upper extremity, studies have detailed the various techniques and coaptations possible at each amputation level to create intuitive myoelectric signals and treat neurogenic pain. Treatment of peripheral nerves in the amputee with TMR should be a consideration for all patients with major upper extremity amputations, especially at large institutions able to support multidisciplinary limb salvage teams. This review article summarizes the current literature and authors' techniques and recommendations surrounding TMR in the upper extremity amputee including techniques relevant to each level of upper extremity amputation.

Identifying discriminant factors between phantom limb pain, residual limb pain, and both in people with lower limb amputations: a cross-sectional study

Postamputation pain is a common condition in patients with lower limb amputation (LLA), which compromises amputees' rehabilitation, use of the prosthesis, and quality of life. The aim of our study was to investigate the prevalence of phantom limb pain (PLP), residual limb pain (RLP), or both types of pain among individuals with LLA, and to identify the factors associated with the presence of one type of pain versus the other. Patients who underwent amputation for traumatic or vascular reasons and who reported on RLP or PLP were analyzed and divided into three groups: PLP, RLP, or a group of subjects that presented both pains. We searched for factors that affect the occurrence of limb pain using univariate analyses, followed by multinomial logistic regression. Among the 282 participants with transtibial and transfemoral amputations, 192 participants (150 male and 42 female) presented PLP, RLP, or both types of pain, while 90 participants declared to perceive no pain. The estimated prevalence of any type of pain after transfemoral and transtibial amputation was therefore 68% (27% PLP, 10% RLP, and 31% both). Among the studied characteristics, only amputation level was associated with the type of pain ( P  = 0.001). Multinomial logistic regression identified transfemoral amputation as the only statistically significant predictor for PLP (odds ratio = 2.8; P  = 0.002). Hence, it was estimated that individuals with transfemoral amputation have nearly three times higher odds of experiencing PLP compared with those with transtibial amputation.

Cortical Tagged Synaptic Long-Term Depression in the Anterior Cingulate Cortex of Adult Mice

The anterior cingulate cortex (ACC) is a key cortical region for pain perception and emotion. Different forms of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), have been reported in the ACC. Synaptic tagging of LTP plays an important role in hippocampus-related associative memory. In this study, we demonstrate that synaptic tagging of LTD is detected in the ACC of adult male and female mice. This form of tagged LTD requires the activation of metabotropic glutamate receptor subtype 1 (mGluR1). The induction of tagged LTD is time-related with the strongest tagged LTD appearing when the interval between two independent stimuli is 30 min. Inhibitors of mGluR1 blocked the induction of tagged LTD; however, blocking N-methyl-d-aspartate receptors did not affect the induction of tagged LTD. Nimodipine, an inhibitor of L-type voltage-gated calcium channels, also blocked tagged LTD. In an animal model of amputation, we found that tagged LTD was either reduced or completely blocked. Together with our previous report of tagged LTP in the ACC, this study strongly suggests that excitatory synapses in the adult ACC are highly plastic. The biphasic tagging of synaptic transmission provides a new form of heterosynaptic plasticity in the ACC which has functional and pathophysiological significance in phantom pain.

Effect of Adding Virtual Reality Training to Traditional Exercise Program on Pain, Mental Status and Psychological Status in Unilateral Traumatic Lower Limb Amputees: A Randomized Controlled Trial

Background: Lower limb amputation is an emotionally devastating condition that causes a complete change in the quality of life, may lead to phantom limb pain in most of the cases, and puts the individual in a high risk of developing psychological disorders. The objective of this study is to evaluate the consequence of adding virtual reality (VR) to a traditional exercise program on pain, mental status, and psychological status in traumatic unilateral lower limb amputees (LLAs). Methods: Thirty-two traumatic LLAs were randomly assigned into two equal groups in this randomized control trial. Participants did accomplish a postfitting exercise program at least 6 months before enrolment; the control group (CG) underwent a traditional rehabilitation program, and experimental group (EG) had the same program, in addition to VR training. Data were collected before and after 6 weeks of intervention using visual analog scale (VAS) for pain, Beck's depression inventory (BDI) for depression, and 12-item short form survey for mental health summary (MHS) and physical health summary (PHS). Results: Thirty-two amputees (29 males and 3 females) were included with mean age in CGs and EG (27.6 ± 4) and (27.6 ± 7.6) years, respectively. Postintervention, the VAS score was significantly reduced only in EG (P = 0.003). Both groups showed significant improvement in BDI, MHS, and PHS (P < 0.05). However, the EG showed a superior significance in BDI and MHS scores (P < 0.05). There was no significance between groups in PHS score. Conclusion: Adding VR to conventional training is beneficial in decreasing pain and in improving depression and MHS of traumatic unilateral LLAs.

Mesenchymal Stem Cell Engagement Modulates Neuroma Microenviroment in Rats and Humans and Prevents Postamputation Pain

Postamputation pain is currently managed unsatisfactorily with neuron-targeted pharmacological and interventional therapies. Non-neuronal pain mechanisms have emerged as crucial factors in the development and persistence of postamputation pain. Consequently, these mechanisms offer exciting prospects as innovative therapeutic targets. We examined the hypothesis that engaging mesenchymal stem cells (MSCs) would foster local neuroimmune interactions, leading to a potential reduction in postamputation pain. We utilized an ex vivo neuroma model from a phantom limb pain patient to uncover that the oligodeoxynucleotide IMT504 engaged human primary MSCs to promote an anti-inflammatory microenvironment. Reverse translation experiments recapitulated these effects. Thus, in an in vivo rat model, IMT504 exhibited strong efficacy in preventing autotomy (self-mutilation) behaviors. This effect was linked to a substantial accumulation of MSCs in the neuroma and associated dorsal root ganglia and the establishment of an anti-inflammatory phenotype in these compartments. Centrally, this intervention reduced glial reactivity in the dorsal horn spinal cord, demonstrating diminished nociceptive activity. Accordingly, the exogenous systemic administration of MSCs phenocopied the behavioral effects of IMT504. Our findings underscore the mechanistic relevance of MSCs and the translational therapeutic potential of IMT504 to engage non-neuronal cells for the prevention of postamputation pain. PERSPECTIVE: The present study suggests that IMT504-dependent recruitment of endogenous MSCs within severely injured nerves may prevent post-amputation pain by modifying the inflammatory scenario at relevant sites in the pain pathway. Reinforcing data in rat and human tissues supports the potential therapeutic value of IMT504 in patients suffering postamputation pain.

Ten-year phantom limb pain with only four sessions of Fu's subcutaneous needling: A case report and systematic review

Phantom limb pain (PLP) is a distressing consequence commonly encountered by individuals who have undergone amputations. The efficacy of treatment options for PLP is limited. In this study, we present a case of a 64-year-old male who suffered from PLP for a duration of 10 years following an above-the-knee amputation. Despite unsuccessful attempts with painkillers and neurotrophic drugs over the course of a decade, the patient sought relief through Fu's Subcutaneous Needling (FSN), an innovative acupuncture therapy that specifically targets the subcutaneous tissue for pain management. Remarkably, the patient experienced a significant reduction in PLP and subsequently decreased his reliance on medication, as well as experiencing improved sleep after undergoing one session of FSN per day for four consecutive days. A follow-up conducted three years later demonstrated positive treatment outcomes. FSN demonstrated a significant influence on PLP, resulting in reduced analgesic requirements and enhanced quality of life. Therefore, FSN may be recommended as an additional treatment option for PLP. In order to gain a comprehensive understanding of the effects of acupuncture on PLP, a systematic review of relevant literature was conducted in PubMed, Embase, Cochrane Library and Web of Science in recent 20 years (from January 1, 2003 to October 16, 2023), using different combinations of the following terms: (phantom acrodynia), (residual limb pain), (phantom limb pain), (acupuncture), (electroacupuncture), (auriculoacupuncture), and (needling). 9 articles with 18 cases including one randomized controlled trial (n = 8) were obtained. This review provided additional evidence supporting the efficacy and safety of needling therapies for PLP. This systematic review offers additional evidence supporting the effectiveness and safety of needling therapies for PLP. However, there were no precedent reports using FSN treatment for PLP. Hence, this case may provide some implications for clinicians in practice.

Case Report: Phantom limb pain relief after cognitive multisensory rehabilitation

Introduction

Relieving phantom limb pain (PLP) after amputation in patients resistant to conventional therapy remains a challenge. While the causes for PLP are unclear, one model suggests that maladaptive plasticity related to cortical remapping following amputation leads to altered mental body representations (MBR) and contributes to PLP. Cognitive Multisensory Rehabilitation (CMR) has led to reduced pain in other neurologic conditions by restoring MBR. This is the first study using CMR to relieve PLP.

Methods

A 26-year-old woman experienced excruciating PLP after amputation of the third proximal part of the leg, performed after several unsuccessful treatments (i.e., epidural stimulator, surgeries, analgesics) for debilitating neuropathic pain in the left foot for six years with foot deformities resulting from herniated discs. The PLP was resistant to pain medication and mirror therapy. PLP rendered donning a prosthesis impossible. The patient received 35 CMR sessions (2×/day during weekdays, October-December 2012). CMR provides multisensory discrimination exercises on the healthy side and multisensory motor imagery exercises of present and past actions in both limbs to restore MBR and reduce PLP.

Results

After CMR, PLP reduced from 6.5-9.5/10 to 0/10 for neuropathic pain with only 4-5.5/10 for muscular pain after exercising on the Numeric Pain Rating Scale. McGill Pain Questionnaire scores reduced from 39/78 to 5/78, and Identity (ID)-Pain scores reduced from 5/5 to 0/5. Her pain medication was reduced by at least 50% after discharge. At 10-month follow-up (9/2013), she no longer took Methadone or Fentanyl. After discharge, receiving CMR as outpatient, she learned to walk with a prosthesis, and gradually did not need crutches anymore to walk independently indoors and outdoors (9/2013). At present (3/2024), she no longer takes pain medication and walks independently with the prosthesis without assistive devices. PLP is under control. She addresses flare-ups with CMR exercises on her own, using multisensory motor imagery, bringing the pain down within 10-15 min.

Conclusion

The case study seems to support the hypothesis that CMR restores MBR which may lead to long-term (12-year) PLP reduction. MBR restoration may be linked to restoring accurate multisensory motor imagery of the remaining and amputated limb regarding present and past actions.

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.

A case of phantom pain and stump pain that was effectively controlled by ultrasound-guided ulnar and median peripheral nerve blocks

Phantom limb pain and stump pain are often intractable, and their incidences are relatively high. We report a case of a patient with phantom limb and stump pain of the finger, who was successfully treated by peripheral nerve blocks. The patient was a male truck driver in his fifties, who had his left annular finger amputated in an accident 2 years previously. Owing to poor pain control at the stump of his finger, he was referred to our department. The initial examination revealed pain about numerical rating scale (NRS) 6/10 in the left annular finger transection as well as allodynia. Although some pain relief had been observed with postoperative medication, he still had persistent resting pain of about NRS 4/10. Therefore, blocks of the ulnar nerve and median nerve were performed. After the blocks were performed, the pain improved to NRS 1 to 2/10, and pain upon movement also almost disappeared. Peripheral nerve blocks can be a useful treatment modality for phantom limb pain and stump pain in the fingers, as in this case.

A novel mixed reality system to manage phantom pain in-home: results of a pilot clinical trial

Introduction

Mirror therapy for phantom limb pain (PLP) is a well-accepted treatment method that allows participants to use a mirror to visually perceive the missing limb. Mixed reality options are now becoming increasingly available, but an in-home virtual mirror therapy option has yet to be adequately investigated.

Methods

We had previously developed a mixed reality system for Managing Phantom Pain (Mr. MAPP) that registers the intact limb and mirrors it onto the amputated limb with the system's visual field, allowing the user to engage with interactive games targeting different large lower limb movements. Feasibility and pilot outcomes of treating patients with lower extremity PLP by using Mr. MAPP at home for 1 month were evaluated in this study. Pain intensity and interference were assessed using the McGill Pain Questionnaire, Brief Pain Inventory, and a daily exercise diary. Function was assessed using the Patient Specific Functional Scale (PSFS). The clinical trial registry number for this study is NCT04529083.

Results

This pilot study showed that it was feasible for patients with PLP to use Mr. MAPP at home. Among pilot clinical outcomes, statistically significant differences were noted in mean current pain intensity [1.75 (SD = 0.46) to 1.125 (SD = 0.35) out of 5, P = .011] and PSFS goal scores [4.28 (SD = 2.27) to 6.22 (SD = 2.58) out of 10, P = .006], with other outcome measures showing non-significant trends towards improvement.

Discussion

This pilot study revealed that in-home use of Mr. MAPP has potential to provide pain relief and improve function in patients with lower extremity PLP and is feasible. Each scale used provided unique perspective on the functional impact of PLP. Further expanded studies and investigation, including a fully powered clinical trial, with these scales are warranted.

Clinical Trial Registration

https://www.clinicaltrials.gov/ct2/show/NCT04529083, Identifier: NCT04529083.

Case report: A combination of mirror therapy and magnetic stimulation to the sacral plexus relieved phantom limb pain in a patient

Phantom limb pain (PLP) is a common sequela of amputation, experienced by 50-80% of amputees. Oral analgesics as the first-line therapy have limited effects. Since PLP usually affects activities of daily living and the psychological conditions of patients, effective treatments are imperatively needed. In this case study, a 49-year-old man was admitted to our hospital because of uncontrollable paroxysmal pain in his missing and residual leg. Due to severe injuries in a truck accident, the right lower limb of the patient was surgically amputated ~5 years ago. Around 1 month after amputation, he felt pain in his lost leg and PLP was diagnosed. Then, he started taking oral analgesics, but the pain still occurred. After admission on July 9, 2022, the patient received treatments of mirror therapy and magnetic stimulation to the sacral plexus. 1-month treatments reduced the frequency and intensity of pain in the phantom limb and the stump, without any adverse events. Analysis of high-resolution three-dimensional T1-weighted brain volume images at the end of 2-month treatments showed alterations in the thickness of cortex regions related to pain processing, compared to that before treatment. This case study gives us hints that one or both interventions of mirror therapy and sacral plexus magnetic stimulation effectively relieved PLP and stump limb pain. These non-invasive, low-cost and easily conducted treatments could be good options for PLP. But randomized controlled trials with a large number of cases are required to confirm their efficacy and safety.

The Efficacy of Graded Motor Imagery and Its Components on Phantom Limb Pain and Disability: A Systematic Review and Meta-Analysis

Introduction

Graded Motor Imagery (GMI) is a non-invasive and inexpensive therapy used to treat Phantom Limb Pain (PLP) by sequentially activating motor networks in such a way that movement and pain are unpaired. The objective of this systematic review was to critically appraise relevant data on the efficacy of GMI and its components for reducing PLP and disability in amputees.

Methods

We searched 11 electronic databases for controlled trials investigating GMI and its components in amputees with PLP from inception until February 2023. Two reviewers independently screened studies and extracted relevant data. Study-level data were entered using the inverse variance function of the Review Manager 5 and pooled with the random effects model.

Results

Eleven studies with varying risk of bias were eligible. No eligible study considered left/right judgement tasks in isolation. Studies showed no effect for imagined movements, but positive effects were seen for GMI [weighted mean difference: -21.29 (95%CI: -31.55, -11.02), I2= 0%] and mirror therapy [weighted mean difference: -8.55 (95%CI: -14.74, -2.35, I2= 61%]. A comparison of mirror therapy versus sham showed no difference [weighted mean difference: -4.43 (95%CI: -16.03, 7.16), I2= 51%].

Conclusion

Our findings suggest that GMI and mirror therapy may be effective for reducing PLP. However, this conclusion was drawn from a limited body of evidence, and the certainty of the evidence was very low. Therefore, rigorous, high-quality trials are needed to address the gap in the literature and inform practice.

When proprioceptive feedback enhances visual perception of self-body movement: rehabilitation perspectives

Introduction

Rehabilitation approaches take advantage of vision's important role in kinesthesia, using the mirror paradigm as a means to reduce phantom limb pain or to promote recovery from hemiparesis. Notably, it is currently applied to provide a visual reafferentation of the missing limb to relieve amputees' pain. However, the efficiency of this method is still debated, possibly due to the absence of concomitant coherent proprioceptive feedback. We know that combining congruent visuo-proprioceptive signals at the hand level enhances movement perception in healthy people. However, much less is known about lower limbs, for which actions are far less visually controlled in everyday life than upper limbs. Therefore, the present study aimed to explore, with the mirror paradigm, the benefit of combined visuo-proprioceptive feedback from the lower limbs of healthy participants.

Methods

We compared the movement illusions driven by visual or proprioceptive afferents and tested the extent to which adding proprioceptive input to the visual reflection of the leg improved the resulting movement illusion. To this end, 23 healthy adults were exposed to mirror or proprioceptive stimulation and concomitant visuo-proprioceptive stimulation. In the visual conditions, participants were asked to voluntarily move their left leg in extension and look at its reflection in the mirror. In the proprioceptive conditions, a mechanical vibration was applied to the hamstring muscle of the leg hidden behind the mirror to simulate an extension of the leg, either exclusively or concomitantly, to the visual reflection of the leg in the mirror.

Results

(i) Visual stimulation evoked leg movement illusions but with a lower velocity than the actual movement reflection on the mirror; (ii) proprioceptive stimulation alone provided more salient illusions than the mirror illusion; and (iii) adding a congruent proprioceptive stimulation improved the saliency, amplitude, and velocity of the illusion.

Conclusion

The present findings confirm that visuo-proprioceptive integration occurs efficiently when the mirror paradigm is coupled with mechanical vibration at the lower limbs, thus providing promising new perspectives for rehabilitation.

Detangling the Structural Neural Correlates Associated with Resting versus Dynamic Phantom Limb Pain Intensity Using a Voxel-based Morphometry Analysis

The management of phantom limb pain (PLP) is still challenging due to a partial understanding of its neurophysiological mechanisms. Structural neuroimaging features are potential biomarkers. However, only a few studies assessed their correlations with clinical severity and treatment response. This study aims to explore the association between brain gray matter volume (GMV) with phantom limb manifestations severity and PLP improvement after neuromodulatory treatments (transcranial direct current stimulation and mirror therapy). Voxel-based morphometry analyses and functional decoding using a reverse inference term-based meta-analytic approach were used. We included 24 lower limb traumatic amputees with moderate to severe PLP. We found that alterations of cortical GMV were correlated with PLP severity but not with other clinical manifestations. Less PLP severity was associated with larger brain clusters GMV in the non-affected prefrontal, insula (non-affected mid-anterior region), and bilateral thalamus. However, only the insula cluster survived adjustments. Moreover, the reverse inference meta-analytic approach revealed that the found insula cluster is highly functionally connected to the contralateral insula and premotor cortices, and the decoded psychological processes related to this cluster were "rating," "sustained attention," "impulsivity, " and "suffering." Moreover, we found that responders to neuromodulatory treatment have higher GMV in somatosensory areas (total volume of S1 and S2) in the affected hemisphere at baseline, compared to non-responders, even after adjustments.

Evolving techniques for reducing phantom limb pain

At least two million people in the United States of America live with lost limbs, and the number is expected to double by 2050, although the incidence of amputations is significantly greater in other parts of the world. Within days to weeks of the amputation, up to 90% of these individuals develop neuropathic pain, presenting as phantom limb pain (PLP). The pain level increases significantly within one year and remains chronic and severe for about 10%. Amputation-induced changes are considered to underlie the causation of PLP. Techniques applied to the central nervous system (CNS) and peripheral nervous system (PNS) are designed to reverse amputation-induced changes, thereby reducing/eliminating PLP. The primary treatment for PLP is the administration of pharmacological agents, some of which are considered but provide no more than short-term pain relief. Alternative techniques are also discussed, which provide only short-term pain relief. Changes induced by various cells and the factors they release are required to change neurons and their environment to reduce/eliminate PLP. It is concluded that novel techniques that utilize autologous platelet-rich plasma (PRP) may provide long-term PLP reduction/elimination.

Perioperative Management of Painful Phantom Limb Syndrome: A Narrative Review and Clinical Management Proposal

Objective: Painful Phantom Limb Syndrome (PPLS) occurs in 50 to 80% of patients undergoing amputation, having a great impact on quality of life, productivity and psychosocial sphere. The objective of this review is to summarize the pharmacological and non-pharmacological strategies, surgical optimization, and provide a multidisciplinary approach aimed at reducing the incidence of chronic pain associated with PPLS in patients undergoing limb amputation.Methods: A narrative review was carried out using Medline, Pubmed, Proquest, LILACS and Cochrane, searching for articles between 2000 and 2021. Articles describing the epidemiology, pathophysiological considerations, and current treatments were selected after a screening process.Results: A multidisciplinary and multimodal approach is required in PPLS, and should include the use of regional techniques, and adjuvants such as NSAIDs, ketamine, lidocaine and gabapentinoids. In addition, an evaluation and continuous management of risk factors for chronic pain in conjunction with the surgical team is necessary.Conclusion: The current literature does not support that a single technique is effective in the prevention of PPLS. However, adequate acute pain control, rehabilitation and early restoration of the body scheme under a multidisciplinary and multimodal approach have shown benefit in the acute setting.

Differential Cortical Oscillatory Patterns in Amputees With and Without Phantom Limb Pain

Introduction

Phantom limb pain (PLP) as neuropathic pain affects the life of amputees. It is believed an efficient PLP treatment should consider the underlying neurological mechanisms. Hereby, we investigated brain activity in PLP and its relationships to the psychological and cognitive dimensions of chronic pain. We investigate differences in resting brain activities between amputees with and without pain. We hypothesize significant differences in the motor cortex and parietal cortex activity that are related to pain perception. Also, we hypothesize two groups have significant differences in cognitive and psychological components.

Methods

Behavioral assessment (psychological status, life satisfaction, and pain level) and EEG signals of 19 amputees (12 without pain and 7 with pain) were recorded. Data were statistically compared between the two groups. Also, the association between behavioral and neurophysiological data was computed.

Results

The results showed a significant decrease in the pain group for the beta and gamma waves, as well as, for the theta and delta waves in the posterior temporal on both sides, during the eye-open condition. The eyes-closed condition showed that the delta waves were decreased on the right side of the cortex. Also, data showed a significant difference in the correlation of pain features with brain waves between the two groups.

Conclusion

Significant differences were mostly observed in regions related to pain perception rather than the motor cortex. This can be due to the learned strategies to deal with pain and the degree of pain. Results showed maladaptive cognitive processes had a relationship with brain wave activities. According to the result of brain wave activities, it seems that cognitive factors have a role in the experience of PLP rather than neuroplasticity through amputation.

Highlights

Differences found in the parietal and temporal regions of phantom limb pain's (PLP's) suggests cognition's role in the persistence of PLP.Decreased delta power at the posterior temporal cortex in PLP's could be the focus of treatments.Increased activity of the parietal cortex could be helpful in the treatment of PLP's.

Plain Language Summary

PLP is an annoying neurologic pain. A wide range of treatments have focused on this type of pain but couldn't be effective. Recently, researchers suggest BCI-based treatments for better treatment. For this type of treatment, we should know the neurological aspect of PLP. In most studies to investigate or treatment of neurological aspects of PLP, researchers induced pain experimentally or studied acute phantom limb pain. We believed for a better understanding of PLP, should investigate it in a natural and stabilized position. Therefore we studied brain activities in amputees with and without PLP in a resting state to find out differences. Trends in this field express the alpha band differences in the motor cortex. On the contrary, our results showed the most significant difference in high-frequency bandpasses such as beta and gamma. Also, in our study, it seems the parietal and temporal cortex that are related to pain perception is the more relevant to PLP. This study showed a psycho-cognitive aspect of pain such as pain exaggeration has a relation with PLP's brain wave activities. So, we can suggest rather than neuroplasticity through amputation, cognitive factors have a role in the experience of PLP.

Effect of mirror therapy in the treatment of phantom limb pain in amputees: A systematic review of randomized placebo-controlled trials does not find any evidence of efficacy

BACKGROUND AND OBJECTIVE

Phantom limb pain (PLP) concerns >50% of amputees and has a negative impact on their rehabilitation, mental health and quality of life. Mirror therapy (MT) is a promising strategy, but its effectiveness remains controversial. We performed a systematic review to: (i) evaluate the effectiveness of MT versus placebo in reducing PLP, and (ii) determine MT effect on disability and quality of life.

DATABASES AND DATA TREATMENT

We selected randomized-controlled trials in five databases (Medline, Cochrane Library, CINAHL, PEDro and Embase) that included patients with unilateral lower or upper limb amputation and PLP and that compared the effects on PLP of MT versus a placebo technique. The primary outcome was PLP intensity changes and the secondary outcomes were PLP duration, frequency, patients' disability and quality of life.

RESULTS

Among the five studies included, only one reported a significant difference between the MT group and control group, with a positive MT effect at week 4. Only one study assessed MT effect on disability and found a significant improvement in the MT group at week 10 and month 6.

CONCLUSIONS

Our systematic review did not allow concluding that MT reduces PLP and disability in amputees. This lack of strong evidence is probably due to (i) the low methodological quality of the included studies, and (ii) the lack of statistical power. Future trials should include a higher number of patients, increase the number and frequency of MT sessions, have a long-term follow-up and improve the methodological quality.

SIGNIFICANCE

Recent meta-analyses concluded that MT is effective for reducing phantom limb pain. Conversely, the present systematic review that included only studies with the best level of evidence did not find any evidence about its effectiveness for this condition. We identified many ways to improve future randomized-controlled trials on this topic: increasing the number of participants, reducing the intra-group heterogeneity, using a suitable placebo and intensifying the MT sessions and frequency.

Virtual and Augmented Reality-based Treatments for Phantom Limb Pain: A Systematic Review

Objective

To evaluate the literature on the effectiveness of virtual reality (VR)- and augmented reality (AR)-based treatments for phantom limb pain (PLP) in postamputation or brachial plexus avulsion (BPA) populations.

Methods

Multiple databases were queried in July 2021 with the keywords "virtual reality," "augmented reality," and "phantom limb pain." Included studies utilized VR or AR to treat PLP with outcome measurement. Two independent reviewers assessed methodological quality using the Physiotherapy Evidence Databsae (PEDro) Scale and the Methodological Index for Nonrandomized Studies (MINORS) scoring. Studies were separated into immersive and nonimmersive AR/VR systems, with further categorization according to the specific methodologies used.

Results

Of 110 results from the database queries, 20 publications met the inclusion criteria. There was one unblinded, randomized, control trial (RCT), one single-blinded, randomized, crossover trial (RCxT), three comparative case series, 13 noncomparative case series, and two case reports. Seven of the 20 studies were classified as nonimmersive. Six studies reported decreased PLP after AR/VR treatments, of which four reported significant reductions. One study reported a reduction in PLP with no significant difference from control conditions. Thirteen of the 20 studies were classified as immersive AR/VR. Twelve studies reported decreased PLP after AR/VR treatments, of which eight reported significant reductions. One study found no change in PLP, compared to baseline.

Conclusion

The number of studies using AR/VR in PLP treatment has expanded since a 2017 review on the topic. The majority of these studies offer support for the efficacy of treating PLP with AR/VR-based treatments. Research has expanded on the customization, outcome measurements, and statistical analysis of AR/VR treatments. While results are promising, most publications remain at the case series level, and clinical indications should be cautioned. With improvements in the quality of evidence, there remain avenues for further investigations, including increased sampling, randomization, optimization of treatment duration, and comparisons to alternative therapies.

A scoping review of current non-pharmacological treatment modalities for phantom limb pain in limb amputees

PURPOSE

Phantom limb pain (PLP) is a chronic neuropathic pain condition of a missing limb following amputation. Pain management is multi-modal, including various non-pharmacological therapies. The purpose of this scoping review was to investigate the evidence surrounding current non-pharmacological treatment modalities for PLP and provide insight into their clinical feasibility.

METHOD

A systematic search was conducted using four databases (Medline, Embase, PsychInfo, and CINAHL) following the PRISMA-ScR method. Results from papers meeting the inclusion criteria were charted to summarize findings, demographics, and use of neuroimaging.

RESULTS

A total of 3387 papers were identified, and full texts of 142 eligible papers were assessed. Eleven treatment modalities for PLP were identified with varying levels of evidence. Overall, there were 25 RCTs, 58 case reports, and 59 a combination of pilot, quasi-experimental, observational, and other study designs.

CONCLUSIONS

Currently, the evidence surrounding most treatment modalities is limited and only a fraction of studies are supported by strong evidence. The findings of this review demonstrated a clear need to conduct more rigorous research with diverse study designs to better understand which modalities provide the most benefit and to incorporate neuroimaging to better determine the neural correlates of PLP and mechanisms of various treatments.Implications for RehabilitationPhantom limb pain (PLP) is a prevalent and debilitating condition following amputation and health care professionals should incorporate an evidence-based pain management protocol into their rehabilitation program.There exist a number of different non-pharmacological therapies to address PLP, however the scientific rigor and levels of evidence vary across modalities.Prescription of interventions for PLP should consider individual patient differences, accessibility to the patient, and quite possibly, a multi-modal approach, particularly for those who also experience residual limb pain.Imagery-based therapies provide the highest level of current evidence based on robust and large randomized control trials, are readily accessible, and are thus most recommended for relief of PLP.

Adults with unilateral lower-limb amputation: greater spatial extent of pain is associated with worse adjustment, greater activity restrictions, and less prosthesis satisfaction

OBJECTIVES

This study's primary purpose was to determine if the extent of bodily pain, as evaluated with pain body diagrams, is associated with prosthetic-related activity restrictions, adjustment, and satisfaction among adults with a major unilateral lower-limb amputation. A secondary objective was to evaluate between-days, test-retest reliability for pain body diagrams among adults with lower-limb amputation.

METHODS

Adults with a lower-limb amputation that occurred ≥1 year prior participated in an online, cross-sectional research study. Outcome measures included pain body diagrams and the Trinity Amputation and Prosthesis Experience Scales-Revised, which evaluates post-amputation activity restrictions, psychosocial adjustment, and prosthesis satisfaction. Linear regression modeling was used to evaluate associations between the number of painful body regions and prosthetic outcomes, after considering covariates (alpha ≤ 0.010). A subset of participants recompleted pain body diagrams to evaluate between-days, test-retest reliability.

RESULTS

Data from 74 participants (n = 32 female; n = 42 transtibial-level; n = 27 traumatic etiology) were available. Beyond covariates (i.e., age, sex, amputation level), the total number of painful body regions was significantly associated with all Trinity Amputation and Prosthesis Experience Scales-Revised subscales (p < 0.001-0.006), with the exception of Social Adjustment (p = 0.764). The total number of painful body regions explained 14.5, 11.8, 11.6, and 7.4% of the variance in Functional Satisfaction with the Prosthesis, Adjustment to Limitation, General Adjustment, and Activity Restriction, respectively. In a subset (n = 54), test-retest reliability for total number of painful body regions per body diagrams was good [intraclass correlation coefficient (ICC)3,1 = 0.84].

CONCLUSIONS

A greater number of painful body regions is associated with greater activity restriction, worse adjustment, and lower prosthesis satisfaction, supporting the need to enhance post-amputation pain management and both amputated- and secondary-site pain prevention.

ETHICAL COMMITTEE NUMBER

IRB #1611862.

Making sense of phantom limb pain

Phantom limb pain (PLP) impacts the majority of individuals who undergo limb amputation. The PLP experience is highly heterogenous in its quality, intensity, frequency and severity. This heterogeneity, combined with the low prevalence of amputation in the general population, has made it difficult to accumulate reliable data on PLP. Consequently, we lack consensus on PLP mechanisms, as well as effective treatment options. However, the wealth of new PLP research, over the past decade, provides a unique opportunity to re-evaluate some of the core assumptions underlying what we know about PLP and the rationale behind PLP treatments. The goal of this review is to help generate consensus in the field on how best to research PLP, from phenomenology to treatment. We highlight conceptual and methodological challenges in studying PLP, which have hindered progress on the topic and spawned disagreement in the field, and offer potential solutions to overcome these challenges. Our hope is that a constructive evaluation of the foundational knowledge underlying PLP research practices will enable more informed decisions when testing the efficacy of existing interventions and will guide the development of the next generation of PLP treatments.

Amputation stump management: A narrative review

In this review intended for medical staff involved in patient rehabilitation, we provided an overview of the basic methods for managing amputation stumps. After the amputation surgery, it is imperative to optimize the remaining physical abilities of the amputee through rehabilitation processes, including postoperative rehabilitation, desensitization, and continuous application of soft or rigid dressings for pain reduction and shaping of the stump. Depending on the situation, a prosthesis may be worn in the early stage of recovery or an immediate postoperative prosthesis may be applied to promote stump maturation. Subsequently, to maintain the range of motion of the stump and to prevent deformation, the remaining portion of the limb should be positioned to prevent contracture. Continuous exercises should also be performed to improve muscle strength to ensure that the amputee is able to perform activities of daily living, independently. Additionally, clean wound or edema management of the stump is necessary to prevent problems associated with wearing the prosthesis. Our review is expected to contribute to the establishment of basic protocols that will be useful for stump management from the time of completion of amputation surgery to the fitting of a prosthesis to optimize patient recovery.

Unveiling the phantom: What neuroimaging has taught us about phantom limb pain

Phantom limb pain (PLP) is a complicated condition with diverse clinical challenges. It consists of pain perception of a previously amputated limb. The exact pain mechanism is disputed and includes mechanisms involving cerebral, peripheral, and spinal origins. Such controversy limits researchers' and clinicians' ability to develop consistent therapeutics or management. Neuroimaging is an essential tool that can address this problem. This review explores diffusion tensor imaging, functional magnetic resonance imaging, electroencephalography, and magnetoencephalography in the context of PLP. These imaging modalities have distinct mechanisms, implications, applications, and limitations. Diffusion tensor imaging can outline structural changes and has surgical applications. Functional magnetic resonance imaging captures functional changes with spatial resolution and has therapeutic applications. Electroencephalography and magnetoencephalography can identify functional changes with a strong temporal resolution. Each imaging technique provides a unique perspective and they can be used in concert to reveal the true nature of PLP. Furthermore, researchers can utilize the respective strengths of each neuroimaging technique to support the development of innovative therapies. PLP exemplifies how neuroimaging and clinical management are intricately connected. This review can assist clinicians and researchers seeking a foundation for applications and understanding the limitations of neuroimaging techniques in the context of PLP.

Visualizing the Unseen: Illustrating and Documenting Phantom Limb Sensations and Phantom Limb Pain With C.A.L.A

Currently, there is neither a standardized mode for the documentation of phantom sensations and phantom limb pain, nor for their visualization as perceived by patients. We have therefore created a tool that allows for both, as well as for the quantification of the patient's visible and invisible body image. A first version provides the principal functions: (1) Adapting a 3D avatar for self-identification of the patient; (2) modeling the shape of the phantom limb; (3) adjusting the position of the phantom limb; (4) drawing pain and cramps directly onto the avatar; and (5) quantifying their respective intensities. Our tool (C.A.L.A.) was evaluated with 33 occupational therapists, physiotherapists, and other medical staff. Participants were presented with two cases in which the appearance and the position of the phantom had to be modeled and pain and cramps had to be drawn. The usability of the software was evaluated using the System Usability Scale and its functional range was evaluated using a self-developed questionnaire and semi-structured interview. In addition, our tool was evaluated on 22 patients with limb amputations. For each patient, body image as well as phantom sensation and pain were modeled to evaluate the software's functional scope. The accuracy of the created body image was evaluated using a self-developed questionnaire and semi-structured interview. Additionally, pain sensation was assessed using the SF-McGill Pain Questionnaire. The System Usability Scale reached a level of 81%, indicating high usability. Observing the participants, though, identified several operational difficulties. While the provided functions were considered useful by most participants, the semi-structured interviews revealed the need for an improved pain documentation component. In conclusion, our tool allows for an accurate visualization of phantom limbs and phantom limb sensations. It can be used as both a descriptive and quantitative documentation tool for analyzing and monitoring phantom limbs. Thus, it can help to bridge the gap between the therapist's conception and the patient's perception. Based on the collected requirements, an improved version with extended functionality will be developed.

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

Phantom limb pain is a chronic pain syndrome that is difficult to cope with. Despite neurostimulation treatment is indicated for refractory neuropathic pain, there is scant evidence from randomized controlled trials to recommend it as the treatment choice. Thus, a systematic review was performed to analyze the efficacy of central nervous system stimulation therapies as a strategy for pain management in patients with phantom limb pain. A literature search for studies conducted between 1970 and September 2020 was carried out using the MEDLINE and Embase databases. Principles of The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline were followed. There were a total of 10 full-text articles retrieved and included in this review. Deep brain stimulation, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and motor cortex stimulation were the treatment strategies used in the selected clinical trials. Repetitive transcranial magnetic stimulation and transcranial direct current stimulation were effective therapies to reduce pain perception, as well as to relieve anxiety and depression symptoms in phantom limb pain patients. Conversely, invasive approaches were considered the last treatment option as evidence in deep brain stimulation and motor cortex stimulation suggests that the value of phantom limb pain treatment remains controversial. However, the findings on use of these treatment strategies in other forms of neuropathic pain suggest that these invasive approaches could be a potential option for phantom limb pain patients.

Indications and outcomes of palliative major amputation in patients with metastatic cancer

BACKGROUND

Patients with stage IV cancer often experience diminished quality of life and pain. Although palliative amputation (PA) can reduce pain, it is infrequently performed because of the morbidity associated with amputation and the limited life expectancy in this population. Here, we describe the indications for PA in patients with stage IV carcinoma or sarcoma and discuss their clinical courses and outcomes. We hypothesized that PA would be associated with reduced pain and improved quality of life in these patients.

METHODS

We retrospectively reviewed medical records of all patients who underwent major amputation (proximal to the ankle or wrist) for metastatic sarcoma or carcinoma from January 1995 to April 2021. We excluded patients who underwent amputation for indications other than palliation. Cox proportional hazards regression analysis was used to determine factors associated with survival after PA.

RESULTS

Twenty-six patients underwent PA (11 for carcinoma, 15 for sarcoma). The most common indications for PA were pain (all patients) and fungating tumor (16 patients). PA was the initial surgery in 7 patients. Forequarter amputations were the most common procedure (6 patients). All patients reported reduced pain after PA, with the mean (±standard deviation) visual analog pain score (on a 10-point scale) decreasing from 5.7 ± 2.9 preoperatively to 0.43 ± 1.3 postoperatively (p < 0.001). The mean preoperative ECOG score was 1.9 ± 0.2 compared with 1.3 ± 0.1 postoperatively (p < 0.001). Fourteen patients were fitted for prostheses (6 upper extremity, 8 lower extremity). Two patients had local recurrence, both within 6 months after PA. The mean survival time after PA was 13 ± 12 months, and mean follow-up was 28 ± 29 months. Mean survival time after PA was not significantly different between patients with sarcoma (11 ± 11 months) versus carcinoma (15 ± 14 months) (p = 0.51). Adjuvant chemotherapy was positively associated with survival; no other factors were associated with survival.

CONCLUSIONS

PA was associated with significantly reduced pain in all patients with stage IV cancer. PA should be considered for those with intractable pain, fungating tumors, or symptoms that diminish quality of life.

LEVEL OF EVIDENCE

Level III.

Home-based transcranial direct current stimulation (tDCS) and motor imagery for phantom limb pain using statistical learning to predict treatment response: an open-label study protocol

Background

Phantom limb pain (PLP) management has been a challenge due to its response heterogeneity and lack of treatment access. This study will evaluate the feasibility of a remotely home-based M1 anodal tDCS combined with motor imagery in phantom limb patients and assess the preliminary efficacy, safety, and predictors of response of this therapy.

Methods

This is a pilot, single-arm, open-label trial in which we will recruit 10 subjects with phantom limb pain. The study will include 20 sessions. All participants will receive active anodal M1 tDCS combined with phantom limb motor imagery training. Our primary outcome will be the acceptability and feasibility of this combined intervention. Moreover, we will assess preliminary clinical (pain intensity) and physiological (motor inhibition tasks and heart rate variability) changes after treatment. Finally, we will implement a supervised statistical learning (SL) model to identify predictors of treatment response (to tDCS and phantom limb motor imagery) in PLP patients. We will also use data from our previous clinical trial (total observations=224 [n=112 x timepoints = 2)) for our statistical learning algorithms. The new prospective data from this open-label study will be used as an independent test dataset.

Discussion

This protocol proposes to assess the feasibility of a novel, neuromodulatory combined intervention that will allow the design of larger remote clinical trials, thus increasing access to safe and effective treatments for PLP patients. Moreover, this study will allow us to identify possible predictors of pain response and PLP clinical endotypes.

Prevention is better than cure: Surgical methods for neuropathic pain prevention following amputation - A systematic review

BACKGROUND

Pain after amputation can be known as residual limb pain (RLP) or phantom limb pain (PLP); however, both can be disabling in daily life with reported incidences of 8% for finger amputations and up to 85% for major limb amputations. The current treatment is focused on reducing the pain after neuropathic pain occurs. However, surgical techniques to prevent neuropathic pain after amputation are available and effective, but they are underutilized. The purpose of the review is to investigate the effects of techniques during amputation to prevent neuropathic pain.

METHODS

A systematic review was performed in multiple databases (Embase, Medline, Web of Science, Scopus, Cochrane, and Google Scholar) and following the PRISMA guidelines. Studies that reported surgical techniques to prevent neuropathic pain during limb amputation were included.

RESULTS

Of the 6188 selected studies, 13 eligible articles were selected. Five articles reported techniques for finger amputation: neurovascular island flap, centro-central union (CCU), and epineural ligatures, and flaps. For finger amputations, the use of prevention techniques resulted in a decrease of incidences from 8% to 0-3% with CCU being the most beneficial. For major limb amputations, the incidences for RLP were decreased to 0 to 55% with TMR and RPNI and compared to 64-91% for the control group. Eight articles reported techniques for amputations on major limbs: targeted muscle reinnervation (TMR), targeted nerve implantation, concomitant nerve coaptation, and regenerative peripheral nerve interface (RPNI).

CONCLUSIONS

Based on the current literature, we state that during finger and major limb amputation, the techniques to prevent neuropathic pain and PLP should be performed.

Contralateral Acupuncture for the Treatment of Phantom Limb Pain and Phantom Limb Sensation in Oncologic Lower Limb Amputee: A Case Report

Phantom limb pain (PLP) and phantom limb sensation (PLS) are common and distressing sequelae of amputation. Current pain management following amputation is challenging and unsatisfying. In this case study, a 74-year-old woman underwent above-knee amputation because of the rhabdomyosarcoma in the right leg. Despite several analgesics, pain was poorly controlled. The phantom limb pain and sensation were immediately reduced by the contralateral acupuncture, and abolished after the third session with no side-effects, no relapse during the next 9 months. Contralateral acupuncture showed positive effect on PLP and PLS in this case, but more robust evidence would be needed to support the efficacy of this treatment technique for indication.

Effects of phantom exercises on pain, mobility, and quality of life among lower limb amputees; a randomized controlled trial

Background

The objective of the current study is to evaluate the effects of phantom exercises on phantom limb pain, mobility status, and quality of life in lower limb amputees treated with mirror therapy and routine physiotherapy.

Methods

It is a randomized controlled trial in which 24 unilateral lower limb amputees (above and below the knee) were randomly assigned to two equal groups i.e., control group (mirror therapy and conventional physical therapy) and experimental group in which, phantom exercises were given, additionally. Physical therapy included conventional therapeutic exercises while phantom exercises include imagining the movement of the phantom limb and attempting to execute these movements Data were collected at baseline, after 2 and 4 weeks of intervention using VAS (pain), AMP (mobility) and RAND SF-36 Version 1.0 (QOL) questionnaires. All statistical analyses were done with IBM SPSS 25.0 with 95% CI.

Results

Twenty-four amputees (17 males and 7 females) participated in this trial. The Mean age of the participants in experimental and control groups was 45.3 ± 11.1 years and 40.5 ± 12.5 years respectively. After the intervention, the pain (VAS score) was significantly lower in the experimental group (p = 0.003). Similarly, the experimental group demonstrated a significantly better score in the “bodily pain” domain of SF-36 (p = 0.012). Both groups significantly (p < 0.05) improved in other domains of SF-36 and ambulatory potential with no significant (p > 0.05) between-group differences.

Conclusions

The Addition of phantom exercises resulted in significantly better pain management in lower limb amputees treated with mirror therapy and routine physiotherapy.

Trial registration

This study is registered in the U.S National Library of Medicine. The clinical trials registration number for this study is NCT04285138 (ClinicalTrials.gov Identifier) (Date: 26/02/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02441-z.

Factors related to phantom limb pain and its effect on quality of life

AIMS

This study aims to investigate phantom limb pain (PLP), PLP-related factors, and the effect of PLP on quality of life in patients who had undergone upper or lower extremity amputation.

METHODS

One hundred four patients with unilateral amputation of the upper or lower extremity were included in this cross-sectional study. The patients were divided into two groups as patients with PLP and without PLP. Patients' demographic (age, gender, marital status, education level, employment status) and clinical information (date of amputation, amputated limb, the side, level and cause of amputation, phantom limb sensation and pain, sleep disorder) and quality of life (Nottingham extended activities of daily living index) were compared between the groups. In addition, factors associated with PLP were analysed.

RESULTS

Of the 104 patients, 47 patients (45.19%) had PLP. In the group with PLP, phantom sensation and sleep disturbance were significantly higher, whereas the time elapsed after amputation and Nottingham extended activities of daily living index score were significantly lower (p < 0.05). The relationship between PLP and sleep disorder and between PLP and marital status was significant (p < 0.05).

CONCLUSIONS

Our study results showed that PLP was associated with sleep disorder and marital status, and the quality of life was low in the group with PLP. Therefore, PLP evaluation should not be disregarded in amputees; PLP should be treated to increase quality of life.

Regenerative Peripheral Nerve Interfaces for the Treatment and Prevention of Neuromas and Neuroma Pain

A neuroma occurs when a regenerating transected peripheral nerve has no distal target to reinnervate. This situation can result in a hypersensitive free nerve ending that causes debilitating pain to affected patients. No techniques to treat symptomatic neuromas have shown consistent results. One novel physiologic solution is the regenerative peripheral nerve interface (RPNI). RPNI consists of a transected peripheral nerve that is implanted into an autologous free skeletal muscle graft. Early clinical studies have shown promising results in the use of RPNIs to treat and prevent symptomatic neuromas. This review article describes the rationale behind the success of RPNIs and its clinical applications.

Auricular Therapy for Treating Phantom Limb Pain Accompanied by Jumping Residual Limb: A Short Review and Case Study

Phantom limb pain (PLP) is a common complaint among patients after amputation, while jumping residual limb is a rare post-amputation complication, they rarely happen at the same time and both remain difficult to manage. At present, there is a paucity of literature on this topic, and no treatment has been proven effective for treating both of them. In the present brief report, we described a patient who developed severe PLP accompanied by jumping residual limb after below-the-knee amputation and she was treated by auricular therapy (AT) with satisfactory effect.

Phantom limb pain: thinking outside the (mirror) box

Despite our best efforts over the past century, our mechanistic understanding of phantom limb pain and our ability to treat it have remained limited. Tamar Makin invites readers to think more critically about some of the most popular approaches to understanding and treating this condition.

Managing Neuroma and Phantom Limb Pain in Ontario: The Status of Targeted Muscle Reinnervation

Supplemental Digital Content is available in the text.

Background:

Painful neuromas (PN) and phantom limb pain (PLP) are common following amputation and are unreliably treated, which impacts quality of life. Targeted muscle reinnervation (TMR) is a microsurgical technique that repairs the severed proximal nerve end to a redundant motor nerve in the amputated stump. Evidence supports TMR as effective in treating PN and PLP; however, its adoption has been slow. This study aimed to characterize: (1) the populations experiencing post-amputation PN/PLP; (2) current trends in managing PN/PLP; and (3) attitudes toward routine use of TMR to manage PN/PLP.

Methods:

A cross-sectional survey was distributed to all orthopedic surgeons, plastic surgeons, and physiatrists practicing in Ontario, via publicly available emails and specialty associations. Data were collected on demographics, experience with amputation, managing post-amputation pain, and attitudes toward routine use of TMR.

Results:

Sixty-six of 698 eligible participants submitted complete surveys (9.5% response rate). Respondents had a greater experience with surgical management of PN (71% PN versus 10% PLP). However, surgery was considered a 3rd-line option for PN and not an option for PLP in 57% and 59% of respondents, respectively. Thirty participants (45%) were unaware of TMR as an option, and only 8 respondents have currently incorporated TMR into their practice. Many (76%) would be willing to incorporate TMR into their practice as either an immediate or delayed surgical technique.

Conclusions:

Despite its promise in managing post-amputation pain, awareness of TMR as a surgical option is generally poor. Several barriers to the widespread adoption of this technique are defined.

Ultrasonography-Guided Radiofrequency Ablation for Painful Stump Neuromas to Relieve Postamputation Pain: A Pilot Study

Objective

Postamputation pain (PAP) is a serious problem, and thus far, there is no perfect treatment strategy. Clinically, minimally invasive treatments for peripheral neuromas are simple and feasible. This study aimed to investigate the immediate and long-term effects of ultrasonography-guided radiofrequency ablation (RFA) on PAP.

Methods

Eighteen PAP subjects with painful peripheral neuromas were treated with ultrasonography-guided RFA.

Results

A total of 18 PAP subjects were included in the final analyses. Fourteen of the 17 subjects with residual limb pain (RLP) (82.4%) had successful outcomes. A successful outcome was noted in 9 of the 13 subjects with phantom limb pain (PLP) (69.2%). There were no significant associations between symptom relief and sex, age, or the duration of symptoms. There were no severe complications.

Conclusions

Ultrasonography-guided RFA for painful stump neuromas can effectively relieve stump pain and PLP in amputees with PAP (follow-up time was 12 months). Ultrasonography-guided RFA is easy and safe and does not involve radiation exposure, making it very suitable for clinical applications.

Brain (re)organisation following amputation: Implications for phantom limb pain

Following arm amputation the region that represented the missing hand in primary somatosensory cortex (S1) becomes deprived of its primary input, resulting in changed boundaries of the S1 body map. This remapping process has been termed 'reorganisation' and has been attributed to multiple mechanisms, including increased expression of previously masked inputs. In a maladaptive plasticity model, such reorganisation has been associated with phantom limb pain (PLP). Brain activity associated with phantom hand movements is also correlated with PLP, suggesting that preserved limb functional representation may serve as a complementary process. Here we review some of the most recent evidence for the potential drivers and consequences of brain (re)organisation following amputation, based on human neuroimaging. We emphasise other perceptual and behavioural factors consequential to arm amputation, such as non-painful phantom sensations, perceived limb ownership, intact hand compensatory behaviour or prosthesis use, which have also been related to both cortical changes and PLP. We also discuss new findings based on interventions designed to alter the brain representation of the phantom limb, including augmented/virtual reality applications and brain computer interfaces. These studies point to a close interaction of sensory changes and alterations in brain regions involved in body representation, pain processing and motor control. Finally, we review recent evidence based on methodological advances such as high field neuroimaging and multivariate techniques that provide new opportunities to interrogate somatosensory representations in the missing hand cortical territory. Collectively, this research highlights the need to consider potential contributions of additional brain mechanisms, beyond S1 remapping, and the dynamic interplay of contextual factors with brain changes for understanding and alleviating PLP.