Prevalence and incidence of phantom limb pain, phantom limb sensations and telescoping in amputees: A systematic rapid review

Pain After Lower Limb Amputations: Insights from the Heidelberg Amputation Registry

Background and Objectives: The experience of unpleasant sensory phenomena after lower limb amputations (LLAs), including phantom limb pain (PLP), phantom limb sensation (PLS), and residual limb pain (RLP), impacts global healthcare and adversely affects outcomes post-amputation. This study aimed to describe the distribution of PLP, PLS, and RLP among patients with LLAs registered in the Heidelberg Amputation Registry. The primary objective was to determine the prevalence of sensory abnormalities across different amputation levels and causes. Materials and Methods: In this single-center, cross-sectional study, data from 459 patients registered in the Heidelberg Amputation Registry were analyzed for the occurrence of PLP, PLS and RLP. Subsequently, logistic regression models were used to identify the independent risk factors associated with sensory disturbances following LLAs. The mean age of the LLA patients (31% female, 69% male) was 58 years (SD ± 18). Results: The patients were, on average, 44 years old (SD ± 22) at the time of amputation, with a mean duration since amputation of 15 years (SD ± 17). Transtibial amputations were the most common (43%), followed by transfemoral (39%) and partial foot amputations (10%). Hip and knee disarticulations were observed in 3.7% and 3.5% of the cohort, respectively, with hemipelvectomies accounting for 1%. Traumatic injuries (32%) and neoplastic disorders (22%) were the leading causes of LLAs, while peripheral artery disease and diabetes were responsible for 12% and 6% of cases, respectively. Importantly, a significant proportion of participants (85%) reported experiencing abnormal sensations. The prevalence rates for phantom limb pain (PLP), phantom limb sensation (PLS), and residual limb pain (RLP) were 58%, 66%, and 46%, respectively. The occurrence of sensory disturbances, with the exception of RLP, was significantly affected by the level of amputation. Notably, the age at amputation emerged as an independent risk factor for developing abnormal sensations, including PLS. Conclusions: In conclusion, this study provides a comprehensive overview of sensory abnormalities in a diverse cohort of LLA patients, highlighting the age at amputation as an important factor. The findings emphasize the role of comprehensive registries in enhancing care for individuals with amputations and guiding targeted pain management strategies.

Neuropsychiatric drugs and a neurophysiological marker as predictors of health-related quality of life in patients with phantom limb pain

OBJECTIVE

To explore the relationship between sociodemographic, clinical, and neurophysiological variables and health-related quality of life (HR-QOL) of patients with phantom limb pain (PLP).

METHODS

This is a cross-sectional analysis of a previous clinical trial. Univariate and multivariate linear and logistic regression analyses were used to model the predictors of HR-QOL. We utilized a sequential modeling approach with increasing adjustment levels, controlling for age and sex, and other relevant clinical variables (time since amputation, level of amputation, and pain). HR-QOL was assessed by the SF-36 Health Survey and its 8 subdomains.

RESULTS

We analyzed baseline data from 92 patients with lower-limb amputations. They were mostly male (63%), 45.2 ± 15.6 years, with a mean time since amputation of 82.7 ± 122.4 months, and an overall SF-36 score of 55.9 ± 21.5. We found an association between intracortical facilitation (ICF) in the affected hemisphere, gabapentin usage, and HR-QOL. ICF is a predictor of better HRQOL, whereas gabapentin usage was associated with a poorer HR-QOL, with the main model explaining 13.4% of the variance in the outcome. For the SF-36 subdomains, ICF was also a positive predictor for social functioning, bodily pain, and vitality, while medication usage was associated with lower scores in mental health, general health perception, bodily pain, and vitality.

CONCLUSION

We found firsthand 2 new independent predictors of HR-QOL in individuals with PLP, namely, the neurophysiological metric ICF and gabapentin usage. These results highlight the role of the motor cortex excitability in the HR-QOL and stress the need for treatments that favor the neuroplastic adaptation after amputation, for which ICF may be used as a possible marker.

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.

Extended reality used in the treatment of phantom limb pain: a multicenter, double-blind, randomized controlled trial

ABSTRACT

Phantom limb pain (PLP) represents a significant challenge after amputation. This study investigated the use of phantom motor execution (PME) and phantom motor imagery (PMI) facilitated by extended reality (XR) for the treatment of PLP. Both treatments used XR, but PME involved overt execution of phantom movements, relying on the decoding of motor intent using machine learning to enable real-time control in XR. In contrast, PMI involved mental rehearsal of phantom movements guided by XR. The study hypothesized that PME would be superior to PMI. A multicenter, double-blind, randomized controlled trial was conducted in 9 outpatient clinics across 7 countries. Eighty-one participants with PLP were randomly assigned to PME or PMI training. The primary outcome was the change in PLP, measured by the Pain Rating Index, from baseline to treatment cessation. Secondary outcomes included various aspects related to PLP, such as the rate of clinically meaningful reduction in pain (CMRP; >50% pain decrease). No evidence was found for superiority of overt execution (PME) over imagery (PMI) using XR. PLP decreased by 64.5% and 68.2% in PME and PMI groups, respectively. Thirty-seven PME participants (71%) and 19 PMI participants (68%) experienced CMRP. Positive changes were recorded in all other outcomes, without group differences. Pain reduction for PME was larger than previously reported. Despite our initial hypothesis not being confirmed, PME and PMI, aided by XR, are likely to offer meaningful PLP relief to most patients. These findings merit consideration of these therapies as viable treatment options and alternatives to pharmacological treatments.

Epidemiology and risk factors for phantom limb pain

Approximately 356 million limb amputations are performed globally every year. In 2005, the prevalence of limb loss in the United States was 1.6 million people; and it is estimated to increase to 3.6 million by 2050. Many post-amputation patients experience chronically altered sensations and pain associated with the amputation, such as phantom limb pain. The risk factors for phantom limb pain are widely debated in the literature due to the heterogeneity of the population being studied. This review will highlight both the non-operative and operative risk factors for phantom limb pain.

Clinician perspectives on postamputation pain assessment and rehabilitation interventions

OBJECTIVE

The purpose of this study was to explore self-reported Veterans Affairs (VA) amputation clinician perspectives and clinical practices regarding the measurement and treatment for amputation-related pain.

STUDY DESIGN

Cross-sectional survey with 73 VA rehabilitation clinicians within the VA Health Care System.

RESULTS

The most frequent clinical backgrounds of respondents included physical therapists (36%), prosthetists (32%), and physical medicine and rehabilitation specialist (21%). Forty-one clinicians (56%) reported using pain outcome measures with a preference for average pain intensity numeric rating scale (generic) (97%), average phantom limb pain intensity numeric rating scale (80%), or Patient-Reported Outcomes Measurement Information System pain interference (12%) measures. Clinicians' most frequently recommended interventions were compression garments, desensitization, and physical therapy. Clinicians identified mindset, cognition, and motivation as factors that facilitate a patient's response to treatments. Conversely, clinicians identified poor adherence, lack of belief in interventions, and preference for traditional pain interventions (e.g., medications) as common barriers to improvement. We asked about the frequently used treatment of graded motor imagery. Although graded motor imagery was originally developed with 3 phases (limb laterality, explicit motor imagery, mirror therapy), clinicians reported primarily using explicit motor imagery and mirror therapy.

RESULTS

Most clinicians who use standardized pain measures prefer intensity ratings. Clinicians select pain interventions based on the patient's presentation. This work contributes to the understanding of factors influencing clinicians' treatment selection for nondrug interventions. Future work that includes qualitative components could further discern implementation barriers to amputation pain rehabilitation interventions for greater consistency in practice.

The Test-Retest Reliability of Pain Outcome Measures in People With Phantom Limb Pain

OBJECTIVES

To quantify the test-retest reliability of 3 patient-reported outcome measures of pain for people living with phantom limb pain (PLP) and assess the impact of test-retest errors on future research and clinical decisions.

METHODS

Thirty-nine participants (30 males), mean (SD) age: 55 (16), mean (SD) years postamputation: 6.8 (8.3), reported their PLP levels on a visual analogue scale (VAS) for pain intensity, the revised short-form McGill Pain Questionnaire (SF-MPQ-2), and a pain diary, on 2 occasions 7 to 14 days apart. Mean systematic change, within-subjects SD, limits of agreement (LOA), coefficient of variation, and the intraclass correlation coefficient (ICC) were quantified alongside their respective 95% confidence intervals (95% CIs).

RESULTS

Systematic learning effects (mean changes) were not clinically relevant across the VAS, SF-MPQ-2, and pain diary. Within-subject SDs (95% CI) were 11.8 (9.6-15.3), 0.9 (0.7-1.2), and 8.6 (6.9-11.5), respectively. LOA (95% CI) were 32.6 (26.5-42.4), 2.5 (2-3.3), and 23.9 (19.2-31.8), respectively. ICCs (95% CI) were 0.8 (0.6-0.9), 0.8 (0.7-0.9), and 0.9 (0.8-0.9), respectively, but may have been inflated by sample heterogeneity. The test-retest errors allowed detection of clinically relevant effect sizes with feasible sample sizes in future studies, but individual errors were large.

DISCUSSION

For people with PLP, a pain intensity VAS, the SF-MPQ-2, and a pain diary show an acceptable level of intersession reliability for use in future clinical trials with feasible sample sizes. Nevertheless, the random error observed for all 3 of the pain outcome measures suggests they should be interpreted with caution in case studies and when monitoring individuals' clinical status and progress.

Development and pilot administration of the amputation-related pain and sensation assessment tool

PURPOSE

To develop and administer an assessment tool for facilitating patient-clinician discussions regarding amputation-related pain and sensation.

MATERIALS AND METHODS

An assessment tool was developed to measure the impact of different types of amputation-related pain and sensation on a patient's life. The tool first provides patients with written descriptions and images of three common types of amputation-related pain or sensations: residual limb pain, phantom limb sensation, and phantom limb pain. The tool then asks them to rate the frequency, intensity, and interference of each experience. Participants were also asked to provide qualitative descriptions of these experiences.

RESULTS

Fifty Veterans with lower limb amputation participated in the study. In the past month, 74% reported experiencing residual limb pain, 76% reported phantom limb sensation, and 84% reported phantom limb pain, with 52% reporting all three. Participants' descriptions of some experiences were distinct, while others (e.g., "tingling") were common between experiences. Phantom limb pain had the most varied descriptions.

CONCLUSIONS

The amputation-related pain and sensation assessment tool can be used to identify and measure the effects of different experiences on patients' lives, thereby improving the specificity of diagnosis and informing clinical treatment recommendations. Further development of this tool should include evaluating its psychometric properties.

The Ceiling Effects of EQ-5D-3L and 5L in General Population Health Surveys: A Systematic Review and Meta-Analysis

OBJECTIVES

This review aims to examine the ceiling effects of EQ-5D-3L (3L) and EQ-5D-5L (5L) in general adult populations and identify the factors influencing these effects.

METHODS

We searched 8 databases for observational studies published in English from inception to 24 July 2023. Ceiling effects were calculated by dividing the number of participants reporting full health at dimension or profile level by the total sample size. Subgroup analysis and meta-regression using the metafor package in R software were performed.

RESULTS

We identified 94 studies from 70 articles, including 4 543 647 adults across 37 countries. The global pooled proportion of individuals reporting full health ("11111") was 56% (95% CI 51%-62%) for 3L and 49% (95% CI 44%-54%) for 5L. The self-care dimension showed the highest ceiling effects (3L: 97%; 5L: 94%), whereas pain/discomfort had the lowest (3L: 69%; 5L: 60%). The ceiling effects in East/South-East Asia were higher than in Europe by 25% (95% CI 18%-32%) in 3L and 9% (95% CI -2%-20%) in 5L. Adjusting for mean age and proportion of males, significant regional differences persisted in the overall profile level of 3L, in all 3L dimensions (except for self-care), and 5L dimensions (except for pain/discomfort and anxiety/depression).

CONCLUSIONS

This review highlights significant ceiling effects in the EQ-5D, especially in Asian populations. The 5L version exhibited fewer ceiling effects than the 3L, indicating its superiority for general population surveys. Further research is crucial to understand the disparities in self-reported health outcomes between Asians and other populations.

Feasibility study of a home-based graded motor imagery intervention (GraMI protocol) for amputees with phantom limb pain

INTRODUCTION

Phantom limb pain affects 64% of amputees. Graded Motor Imagery comprises three consecutive application techniques designed to reorganize maladaptive changes that have occurred after the amputation.

OBJECTIVE

To assess the feasibility of a home-based Graded Motor Imagery intervention, the GraMI protocol, for amputee people with phantom limb pain.

METHODS

Twenty individuals over 18 years of age with upper or lower limb amputation, experiencing phantom limb pain, who were pharmacologically stable, and had been discharged from the hospital were recruited. The experimental group followed the GraMI protocol. Primary outcomes included study processes, such as recruitment time and rate, adherence, compliance, and the acceptability of digital technologies as a treatment tool. Secondary outcomes assessed the impact on phantom limb pain, quality of life, functionality, and depressive symptoms.

RESULTS

On average, seven participants were recruited monthly over a three-month period. No losses were recorded throughout the nine weeks of intervention. Treatment adherence averaged 89.32%, and all participants demonstrated familiarity with the usability of digital technologies. No significant differences were observed between groups (p = .054). However, within the experimental group, intragroup analysis revealed a significant (p = .005) and clinically relevant reduction (>2 points) with a large effect size (0.89) in phantom limb pain.

CONCLUSION

Conducting a multicenter study with a home-based intervention using the GraMI protocol is feasible. Future clinical trials are needed to verify its effectiveness in managing phantom limb pain.

A systematic review of the prevalence of postamputation and chronic neuropathic pain associated with combat injury in military personnel

ABSTRACT

Combat trauma can lead to widespread tissue damage and limb loss. This may result in chronic neuropathic and post amputation pain, including phantom limb pain (PLP) and residual limb pain (RLP). The military population is distinct with respect to demographic, injury, and social characteristics compared with other amputation and trauma cohorts. We undertook a systematic review of studies of military personnel, with a history of combat injury, that reported a prevalence of any type of postamputation pain or chronic neuropathic pain, identified from Embase and MEDLINE databases.Using the inverse variance method with a random-effects model, we undertook a meta-analysis to determine an overall prevalence and performed exploratory analyses to identify the effect of the type of pain, conflict, and time since injury on prevalence. Pain definitions and types of pain measurement tools used in studies were recorded. Thirty-one studies (14,738 participants) were included. The pooled prevalence of PLP, RLP, and chronic neuropathic pain were 57% (95% CI: 46-68), 61% (95% CI: 50-71), and 26% (95% CI: 10-54), respectively. Between-study heterogeneity was high (I 2 : 94%-98%). Characterisation of duration, frequency, and impact of pain was limited. Factors reported by included studies as being associated with PLP included the presence of RLP and psychological comorbidity. The prevalence of postamputation pain and chronic neuropathic pain after combat trauma is high. We highlight inconsistency of case definitions and terminology for pain and the need for consensus in future research of traumatic injury.

Pain in the Context of Sensory Deafferentation

Pain that accompanies deafferentation is one of the most mysterious and misunderstood medical conditions. Prevalence rates for the assorted conditions vary considerably but the most reliable estimates are greater than 50% for strokes involving the somatosensory system, brachial plexus avulsions, spinal cord injury, and limb amputation, with controversy surrounding the mechanistic contributions of deafferentation to ensuing neuropathic pain syndromes. Deafferentation pain has also been described for loss of other body parts (e.g., eyes and breasts) and may contribute to between 10% and upwards of 30% of neuropathic symptoms in peripheral neuropathies. There is no pathognomonic test or sign to identify deafferentation pain, and part of the controversy surrounding it stems from the prodigious challenges in differentiating cause and effect. For example, it is unknown whether cortical reorganization causes pain or is a byproduct of pathoanatomical changes accompanying injury, including pain. Similarly, ascertaining whether deafferentation contributes to neuropathic pain, or whether concomitant injury to nerve fibers transmitting pain and touch sensation leads to a deafferentation-like phenotype can be clinically difficult, although a detailed neurologic examination, functional imaging, and psychophysical tests may provide clues. Due in part to the concurrent morbidities, the physical, psychologic, and by extension socioeconomic costs of disorders associated with deafferentation are higher than for other chronic pain conditions. Treatment is symptom-based, with evidence supporting first-line antineuropathic medications such as gabapentinoids and antidepressants. Studies examining noninvasive neuromodulation and virtual reality have yielded mixed results.

Phantom Limb Pain and Painful Neuroma After Dysvascular Lower-Extremity Amputation: A Systematic Review and Meta-Analysis

BACKGROUND

Phantom limb pain (PLP) and symptomatic neuroma can be debilitating and significantly impact the quality of life of amputees. However, the prevalence of PLP and symptomatic neuromas in patients following dysvascular lower limb amputation (LLA) has not been reliably established. This systematic review and meta-analysis evaluates the prevalence and incidence of phantom limb pain and symptomatic neuroma after dysvascular LLA.

METHODS

Four databases (Embase, MEDLINE, Cochrane Central, and Web of Science) were searched on October 5th, 2022. Prospective or retrospective observational cohort studies or cross-sectional studies reporting either the prevalence or incidence of phantom limb pain and/or symptomatic neuroma following dysvascular LLA were identified. Two reviewers independently conducted the screening, data extraction, and the risk of bias assessment according to the PRISMA guidelines. To estimate the prevalence of phantom limb pain, a meta-analysis using a random effects model was performed.

RESULTS

Twelve articles were included in the quantitative analysis, including 1924 amputees. A meta-analysis demonstrated that 69% of patients after dysvascular LLA experience phantom limb pain (95% CI 53-86%). The reported pain intensity on a scale from 0-10 in LLA patients ranged between 2.3 ± 1.4 and 5.5 ± .7. A single study reported an incidence of symptomatic neuroma following dysvascular LLA of 5%.

CONCLUSIONS

This meta-analysis demonstrates the high prevalence of phantom limb pain after dysvascular LLA. Given the often prolonged and disabling nature of neuropathic pain and the difficulties managing it, more consideration needs to be given to strategies to prevent it at the time of amputation.

The missing pieces: an investigation into the parallels between Charles Bonnet, phantom limb and tinnitus syndromes

Charles Bonnet syndrome (CBS) is a condition characterised by visual hallucinations of varying complexity on a background of vision loss. CBS research has gained popularity only in recent decades, despite evidence dating back to 1760. Knowledge of CBS among both the patient and professional populations unfortunately remains poor, and little is known of its underlying pathophysiology. CBS parallels two other better-known conditions that occur as a result of sensory loss: phantom limb syndrome (PLS) (aberrant sensation of the presence of a missing limb) and tinnitus (aberrant sensation of sound). As 'phantom' conditions, CBS, PLS and tinnitus share sensory loss as a precipitating factor, and, as subjective perceptual phenomena, face similar challenges to investigations. Thus far, these conditions have been studied separately from each other. This review aims to bridge the conceptual gap between CBS, PLS and tinnitus and seek common lessons between them. It considers the current knowledge base of CBS and explores the extent to which an understanding of PLS and tinnitus could provide valuable insights into the pathology of CBS (including the roles of cortical reorganisation, emotional and cognitive factors), and towards identifying effective potential management for CBS.

Pain and Reorganization after Amputation: Is Interoceptive Prediction a Key?

There is an ongoing discussion on the relevance of brain reorganization following amputation for phantom limb pain. Recent attempts to provide explanations for seemingly controversial findings-specifically, maladaptive plasticity versus persistent functional representation as a complementary process-acknowledged that reorganization in the primary somatosensory cortex is not sufficient to explain phantom limb pain satisfactorily. Here we provide theoretical considerations that might help integrate the data reviewed and suppose a possible additional driver of the development of phantom limb pain-namely, an error in interoceptive predictions to somatosensory sensations and movements of the missing limb. Finally, we derive empirically testable consequences based on our considerations to guide future research.

Risk Factors Analysis of Phantom Limb Pain in Amputees with Malignant Tumors

Purpose

Postamputation neuropathic pain is a common disease in patients with malignant tumor amputation, seriously affecting amputees' quality of life and mental health. The objective of this study was to identify independent risk factors for phantom limb pain in patients with tumor amputation and to construct a risk prediction model.

Methods

Patients who underwent amputation due to malignant tumors from 2013 to 2023 were retrospectively analyzed and divided into phantom limb pain group and non-phantom limb pain group. To determine which preoperative factors would affect the occurrence of phantom limb pain, we searched for candidate factors by univariate analysis and used multivariate logistic regression analysis to identify independent factors and construct a predictive model. The receiver operating characteristic curve (ROC) was drawn to further evaluate the accuracy of the prediction model in evaluating the phantom limb pain after amputation of bone and soft tissue tumors.

Results

Multivariate analysis showed that age (OR, 1.054; 95% CI, 1.027 to 1.080), preoperative pain (OR, 5.773; 95% CI, 2.362 to 14.104), number of surgeries (OR, 3.425; 95% CI, 1.505 to 7.795), amputation site (OR, 5.848; 95% CI, 1.837 to 18.620), amputation level (OR, 8.031; 95% CI, 2.491 to 25.888) were independent risk factors for phantom limb pain for bone and soft tissue tumors. The the area under the curve (AUC) of this model was 0.834.

Conclusion

Risk factors for postoperative phantom limb pain were the site of amputation, proximal amputation, preoperative pain, multiple amputations, and older age. These factors will help surgeons to individualize and stratify phantom limb pain and help patients with risk counseling. In particular, an informed clinical decision targeting those modifiable factors can be considered when needed.

Altered cortical thickness and structural covariance networks in upper limb amputees: A graph theoretical analysis

BACKGROUND

The extensive functional and structural remodeling that occurs in the brain after amputation often results in phantom limb pain (PLP). These closely related phenomena are still not fully understood.

METHODS

Using magnetic resonance imaging (MRI) and graph theoretical analysis (GTA), we explored how alterations in brain cortical thickness (CTh) and structural covariance networks (SCNs) in upper limb amputees (ULAs) relate to PLP. In all, 45 ULAs and 45 healthy controls (HCs) underwent structural MRI. Regional network properties, including nodal degree, betweenness centrality (BC), and node efficiency, were analyzed with GTA. Similarly, global network properties, including global efficiency (Eglob), local efficiency (Eloc), clustering coefficient (Cp), characteristic path length (Lp), and the small-worldness index, were evaluated.

RESULTS

Compared with HCs, ULAs had reduced CThs in the postcentral and precentral gyri contralateral to the amputated limb; this decrease in CTh was negatively correlated with PLP intensity in ULAs. ULAs showed varying degrees of change in node efficiency in regional network properties compared to HCs (p < 0.005). There were no group differences in Eglob, Eloc, Cp, and Lp properties (all p > 0.05). The real-worldness SCN of ULAs showed a small-world topology ranging from 2% to 34%, and the area under the curve of the small-worldness index in ULAs was significantly different compared to HCs (p < 0.001).

CONCLUSION

These results suggest that the topological organization of human CNS functional networks is altered after amputation of the upper limb, providing further support for the cortical remapping theory of PLP.

Integration of proprioception in upper limb prostheses through non-invasive strategies: a review

Proprioception plays a key role in moving our body dexterously and effortlessly. Nevertheless, the majority of investigations evaluating the benefits of providing supplemental feedback to prosthetics users focus on delivering touch restitution. These studies evaluate the influence of touch sensation in an attempt to improve the controllability of current robotic devices. Contrarily, investigations evaluating the capabilities of proprioceptive supplemental feedback have yet to be comprehensively analyzed to the same extent, marking a major gap in knowledge within the current research climate. The non-invasive strategies employed so far to restitute proprioception are reviewed in this work. In the absence of a clearly superior strategy, approaches employing vibrotactile, electrotactile and skin-stretch stimulation achieved better and more consistent results, considering both kinesthetic and grip force information, compared with other strategies or any incidental feedback. Although emulating the richness of the physiological sensory return through artificial feedback is the primary hurdle, measuring its effects to eventually support the integration of cumbersome and energy intensive hardware into commercial prosthetic devices could represent an even greater challenge. Thus, we analyze the strengths and limitations of previous studies and discuss the possible benefits of coupling objective measures, like neurophysiological parameters, as well as measures of prosthesis embodiment and cognitive load with behavioral measures of performance. Such insights aim to provide additional and collateral outcomes to be considered in the experimental design of future investigations of proprioception restitution that could, in the end, allow researchers to gain a more detailed understanding of possibly similar behavioral results and, thus, support one strategy over another.

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.

Altered bodily perceptions in chronic neuropathic pain conditions and implications for treatment using immersive virtual reality

Chronic neuropathic pain is highly disabling and difficult to treat and manage. Patients with such conditions often report altered bodily perceptions that are thought to be associated with maladaptive structural and functional alterations in the somatosensory cortex. Manipulating these altered perceptions using body illusions in virtual reality is being investigated and may have positive clinical implications for the treatment of these conditions. Here, we have conducted a narrative review of the evidence for the types of bodily distortions associated with a variety of peripheral and central neuropathic pain conditions. In addition, we summarize the experimental and clinical studies that have explored embodiment and body transformation illusions in immersive virtual reality for neuropathic pain relief, which are thought to target these maladaptive changes, as well as suggesting directions for future research.

Diagnosis and Management of Traumatic Hemipelvectomy

Traumatic hemipelvectomy (THP) is a catastrophic injury associated with high-energy trauma and high mortality. THP has been defined as a complete dislocation of the hemipelvis, often with disruption through the symphysis pubis and sacroiliac joint with concurrent traumatic rupture of the iliac vessels. Despite recent advances in prehospital resuscitative techniques, the true incidence of THP is difficult to ascertain because many patients die before hospital arrival. The leading causes of death associated with THP include blood loss, infection, and multiple system organ failure. Recognition and immediate intervention for these injuries is imperative for survival. The initial assessment includes a thorough physical examination assessing for signs of arterial damage and other associated injuries. Hemorrhage control and vigorous resuscitation should be prioritized to combat impending exsanguination. Emergent amputation has been found to be a lifesaving operation in these patients. The basis of this approach is rooted in achieving complete hemostasis while reducing complication rates. Understanding the nature of these massive pelvic injuries, the role of early amputation, and the importance of subspecialty communication can improve survivability and optimize patient outcomes.

A Rare Occurrence of Phantom Tongue Pain

This is a case of phantom tongue pain observed in a 65-year-old male with a history of adenoid cystic carcinoma with involvement of the base of the tongue and supraglottic laryngopharyngeal cancer who underwent a laryngopharyngectomy and glossectomy for treatment. The patient subsequently developed phantom tongue pain in acute rehabilitation. Post total glossectomy phantom pain is rare, and as this is a singular appendage, current techniques that rely on the presence of an intact limb, such as mirror therapy could not be applied to our patient. Therefore mental imagery techniques originally developed for extremity amputation required adaptation to the context of total glossectomy. Recommended anticonvulsant medications, desensitization, and mental imagery techniques for phantom limb pain were effective in relieving the patient’s phantom tongue pain. Utilizing therapeutic desensitization techniques may allow for the direction of neuroplasticity in order to decrease pain.

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.

Prophylactic Regenerative Peripheral Nerve Interfaces in Elective Lower Limb Amputations

Regenerative peripheral nerve interface (RPNI) is a relatively new surgical technique to manage neuromas and phantom pain after limb amputation. This study evaluates prophylactic RPNI efficacy in managing post-amputation pain and neuroma formation in amputees compared with patients in which lower limb amputation was performed without this procedure. We included 28 patients who underwent above the knee amputation (AKA) or below the knee amputation (BKA) for severe soft tissue infection from July 2019 till December 2020. All patients had insulin-dependent diabetes. The patients were divided into two groups, 14 patients with primary RPNI and 14 patients without. We analyzed the demographic data, level of amputation, number of RPNIs, operative time, postoperative complications and functional outcome on the defined follow up period. The mean patient age was 68.6 years (range 49-85), 19 (67.9 %) male and 9 (32.1 %) female patients. In this study 11 (39.3 %) AKA and 17 (60.7 %) BKA were performed. Overall, 37 RPNIs were made. The mean follow-up period was 49 weeks. PROMIS T-score decreased by 15.9 points in favor for the patients with RPNI. The VAS score showed that, in the RPNI group, all 14 patients were without pain compared to the group of patients without RPNI, where the 11 (78.6 %) patients described their pain as severe. Patients with RPNI used prosthesis significantly more (p < 0.005). Data showed significant reduction in pain and high patient satisfaction after amputation with RPNIs. This technique is oriented as to prevent neuroma formation with RPNI surgery, performed at the time of amputation. RPNI surgery did not provoke complications or significant lengthening of operative time and it should be furthermore exploited as a surgical technique.

Statistical analysis plan for an international, double-blind, randomized controlled clinical trial on the use of phantom motor execution as a treatment for phantom limb pain

Background

Phantom limb pain (PLP) is a detrimental condition that can greatly diminish the quality of life. Purposeful control over the phantom limb activates the affected neural circuitry and leads to dissolution of the pathological relationship linking sensorimotor and pain processing (which gives rise to PLP). An international, double-blind, randomized controlled clinical trial (RCT) on the use of phantom motor execution (PME) as a treatment for PLP is currently undertaken, where PME is compared to an active placebo treatment, namely phantom motor imagery (PMI).

Methods and design

Sixty-seven subjects suffering from PLP in upper or lower limbs are randomly assigned in 2:1 ratio to PME or PMI interventions respectively. Subjects allocated to either treatment receive 15 interventions where they are exposed to the same VR-AR environments using the same device. The only difference between interventions is whether phantom movements are performed (PME) or imagined (PMI).

Results

The primary outcome of the study is to examine whether 15 sessions of PME can induce a greater PLP relief, compared to PMI. The secondary objectives are to examine whether 15 sessions of PME provide a greater improvement in different aspects related to PLP compared to PMI, such as pain duration, pain intensity as measured by other metrics, and the patient’s own impression about the effect of treatment. Long-term retention of treatment benefits will be assessed as change in all the variables (both primary and secondary) between baseline and follow-up timepoints (at 1, 3, and 6 months post-treatment).

Conclusion

This manuscript serves as the formal statistical analysis plan (version 1.0) for the international, double-blind, randomized controlled clinical trial on the use of PME as a treatment for PLP. The statistical analysis plan was completed on 3 August 2021.

Trial registration

ClinicalTrials.govNCT03112928. Registered on April 13, 2017

SAP version: version: 1.0, date: 2021/08/03

Protocol version: This document has been written based on information contained in the study protocol published in Lendaro et al. (BMJ Open 8:e021039, 2018), in July 2018.

SAP revisions: Not applicable

Characteristics of phantom limb pain in U.S. civilians and service members

OBJECTIVES

The population of Americans with limb loss is on the rise, with a different profile than in previous generations (e.g., greater incidence of amputation due to diabetes). This study aimed to identify the key characteristics of phantom limb sensation (PLS) and pain (PLP) in a current sample of Americans with limb loss.

METHODS

This cross-sectional study is the first large-scale (n=649) study on PLP in the current population of Americans with limb loss. A convenience sample of military and civilian persons missing one or more major limbs was surveyed regarding their health history and experience with phantom limb phenomena.

RESULTS

Of the participants surveyed, 87% experienced PLS and 82% experienced PLP. PLS and PLP typically first occurred immediately after amputation (47% of cases), but for a small percentage (3-4%) onset did not occur until over a year after amputation. Recent PLP severity decreased over time (β=0.028, 95% CI: -0.05-0.11), but most participants reported PLP even 10 years after amputation. Higher levels of recent PLP were associated with telescoping (β=0.123, 95% CI: 0.04-0.21) and higher levels of pre-amputation pain (β=0.104, 95% CI: 0.03-0.18). Those with congenitally missing limbs experienced lower levels of recent PLP (t (37.93)=3.93, p<0.01) but there were no consistent differences in PLP between other amputation etiologies.

CONCLUSIONS

Phantom limb phenomena are common and enduring. Telescoping and pre-amputation pain are associated with higher PLP. Persons with congenitally missing limbs experience lower levels of PLP than those with amputation(s), yet PLP is common even in this subpopulation.

Body Schema Self-Awareness and Related Dream Content Modifications in Amputees Due to Cancer

PURPOSE

the evaluation of body image perception, pain coping strategies, and dream content, together with phantom limb and telescoping phenomena in patients with sarcoma who underwent surgery for limb amputation.

MATERIAL AND METHODS

consecutive outpatients were evaluated at T0 (within 3 weeks after surgery) and T1 (4-6 months after surgery) as follows: demographic and clinical data collection; the Groningen Questionnaire Problems after Arm Amputation; the West Haven-Yale Multidimensional Pain Inventory; the Body Image Concern Inventory, a clinical trial to identify telescoping; and a weekly diary of dreams. Dream contents were coded according to the Hall and Van de Castle coding system.

RESULTS

Twenty patients completed the study (15 males and 5 females, mean age: 53.9 ± 24.6, education: 7.8 ± 3.4). All subjects experienced phantom limb and 35% of them experienced telescoping soon after surgery, and 25% still after 4-6 months. Both at T0 and T1, that half of the subjects reported dreams about still having their missing limbs. At T1 the patients' perceptions of being able to deal with problems were lower, and pain and its interference in everyday life were higher yet associated with significant engagement in everyday activities and an overall good mood. The dream content analysis highlighted that males were less worried about health problems soon after amputation, and women showed more initial difficulties that seemed to be resolved after 4-6 months after surgery.

CONCLUSIONS

The dream content analysis may improve clinicians' ability to support their patients during their therapeutic course.

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.

Early life experience sets hard limits on motor learning as evidenced from artificial arm use

The study of artificial arms provides a unique opportunity to address long-standing questions on sensorimotor plasticity and development. Learning to use an artificial arm arguably depends on fundamental building blocks of body representation and would therefore be impacted by early life experience. We tested artificial arm motor-control in two adult populations with upper-limb deficiencies: a congenital group—individuals who were born with a partial arm, and an acquired group—who lost their arm following amputation in adulthood. Brain plasticity research teaches us that the earlier we train to acquire new skills (or use a new technology) the better we benefit from this practice as adults. Instead, we found that although the congenital group started using an artificial arm as toddlers, they produced increased error noise and directional errors when reaching to visual targets, relative to the acquired group who performed similarly to controls. However, the earlier an individual with a congenital limb difference was fitted with an artificial arm, the better their motor control was. Since we found no group differences when reaching without visual feedback, we suggest that the ability to perform efficient visual-based corrective movements is highly dependent on either biological or artificial arm experience at a very young age. Subsequently, opportunities for sensorimotor plasticity become more limited.

Electroacupuncture For Alleviation Of Phantom Limb Pain

Phantom limb pain is clinically defined as the perception of pain or discomfort in a limb that no longer exists. Most amputees will experience phantom limb pain, which is associated with a low health-related quality of life. Phantom limb pain represents an important challenge in finding an effective therapy. The scientific evidence for best practice is weak, and is characterized by various clinical reports describing the pragmatic use of drugs and interventional techniques. Recent approaches to restore the sensory motor input have shown promise. One such technique is electroacupuncture. We report here a case study of a male in his 30s who sustained severe injuries, including a high transfemoral amputation, as a result of being hit by a car. An electroacupuncture treatment protocol was used. Over the course of 3 months, electroacupuncture alleviated the patient’s phantom limb pain, minimized his use of drugs, and improved his sleep and quality of life. The effect of electroacupuncture treatment lasted for 3–4 months, and successful top-up treatment maintained his pain relief. The results are in line with a study comparing massage and electroacupuncture in patients with spinal cord injury with neurogenic pain; a limited number of patients treated with electroacupuncture were significantly alleviated of their pain for months. This case report suggests that electroacupuncture may be useful in patients with phantom limb pain.