Factors affecting phantom limb pain in patients undergoing amputation: retrospective study

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.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

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.

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.

An Algorithm Approach to Phantom Limb Pain

Phantom limb pain (PLP) is a common condition that occurs following both upper and lower limb amputation. First recognized and described in 1551 by Ambroise Pare, research into its underlying pathology and effective treatments remains a very active and growing field. To date, however, there is little consensus regarding the optimal management of phantom limb pain. With few large well-designed clinical trials of which to make treatment recommendations, as well as significant heterogeneity in clinical response to available treatments, the management of PLP remains challenging. Below we summarize the current state of knowledge in the field, as well as propose an algorithm for the approach to the treatment of PLP.

Phantom Limb Pain and Sensations in Chinese Malignant Tumor Amputees: A Retrospective Epidemiological Study

OBJECTIVE

Phantom limb pain (PLP) was a common problem in malignant tumor amputees that can cause considerable suffering. The purposes of this study were to determine the incidence and factors associated with the occurrence of post-operation PLP, stump limb pain (SLP), and phantom limb sensations (PLS) in tumor amputees within the first month after surgery. Additionally, differences in phantom phenomena between upper and lower extremities were investigated.

METHODS

In total, 162 amputees participated in this retrospective study who underwent malignant limb amputation between 2012 and 2019. Clinical characteristics were collected from medical records and reconfirmed by telephone interviews. A numerical rating scale (NRS) was used to quantitate phantom phenomena. We used analysis of variance and non-parametric statistics for categorical variables and ordinal variables separately.

RESULTS

In the first month after malignant amputation, the incidence of PLP was 54.3%, that of PLS was 65.4%, and that of SLP was 32.7%. The duration of preoperative pain and amputation level was significantly different for the incidence of acute PLP. Further subgroup analysis of amputation level showed that patients whose amputation level was below the wrist and ankle joints had a significantly reduced incidence of PLP (p<0.0083 in Bonferroni test). Binary logistics regression analysis determined that amputation level was the primary risk factor for the incidence of PLP. Factors related to the severity of postoperative PLP also included amputation level, preoperative pain, and amputation times. By comparing the differences between upper and lower limbs after amputation, we found that the incidence of PLS was higher after lower limb amputation, but there was no significant difference in the incidence of PLP and SLP. Preoperative experience of chemotherapy was not a risk factor for PLP.

CONCLUSION

Proximal amputation and long-term preoperative pain seemed to count more for PLP incidence. Further research may be required to individually determine factors associated with the occurrence and chronicity of phantom phenomena.

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.

The prevalence and risk factors for phantom limb pain in people with amputations: A systematic review and meta-analysis

Background

Phantom limb pain (PLP)—pain felt in the amputated limb–is often accompanied by significant suffering. Estimates of the burden of PLP have provided conflicting data. To obtain a robust estimate of the burden of PLP, we gathered and critically appraised the literature on the prevalence and risk factors associated with PLP in people with limb amputations.

Methods

Articles published between 1980 and July 2019 were identified through a systematic search of the following electronic databases: MEDLINE/PubMed, PsycINFO, PsycArticles, Cumulative Index to Nursing and Allied Health Literature, Africa-Wide Information, Health Source: Nursing/Academic Edition, SCOPUS, Web of Science and Academic Search Premier. Grey literature was searched on databases for preprints. Two reviewers independently conducted the screening of articles, data extraction and risk of bias assessment. The meta-analyses were conducted using the random effects model. A statistically significant level for the analyses was set at p<0.05.

Results

The pooling of all studies demonstrated a prevalence estimate of 64% [95% CI: 60.01–68.05] with high heterogeneity [I² = 95.95% (95% CI: 95.10–96.60)]. The prevalence of PLP was significantly lower in developing countries compared to developed countries [53.98% vs 66.55%; p = 0.03]. Persistent pre-operative pain, proximal site of amputation, stump pain, lower limb amputation and phantom sensations were identified as risk factors for PLP.

Conclusion

This systematic review and meta-analysis estimates that six of every 10 people with an amputation report PLP–a high and important prevalence of PLP. Healthcare professionals ought to be aware of the high rates of PLP and implement strategies to reduce PLP by addressing known risk factors, specifically those identified by the current study.

[Perioperative measures for prevention of phantom pain: an evidence-based approach to risk reduction]

Prevention of phantom limb pain is one of the biggest and still largely unsolved challenges in perioperative medicine. Despite many study efforts and optimization of postoperative pain treatment over the last 30 years, a significant reduction in the incidence of phantom limb pain has not been achieved. Current studies have also shown that at least 50% of patients develop phantom pain after 6 months. A possible approach could be to combine multiple synergistic interventions and implement them as a perioperative phantom pain management strategy bundle. In addition to regional anesthesia, NMDA antagonists, gabapentinoids, antidepressants and systemic lidocaine could play a relevant role. The aim of this pharmacological intervention was the modification of the pathophysiological changes in peripheral nerves and in the central nervous system after amputation.

Protective and Risk Factors for Phantom Limb Pain and Residual Limb Pain Severity

INTRODUCTION

The exact mechanisms underlying the development and maintenance of phantom limb pain (PLP) are still unclear. This study aimed to identify the factors affecting pain intensity in patients with chronic, lower limb, traumatic PLP.

METHODS

This is a cross-sectional analysis of patients with PLP. We assessed amputation-related and pain-related clinical and demographic variables. We used univariate and multivariate models to evaluate the associated factors modulating PLP and residual limb pain (RLP) intensity.

RESULTS

We included 71 unilateral traumatic lower limb amputees. Results showed that (1) amputation-related perceptions were experienced by a large majority of the patients with chronic PLP (sensations: 90.1%, n = 64; residual pain: 81.7%, n = 58); (2) PLP intensity has 2 significant protective factors (phantom limb movement and having effective treatment for PLP previously) and 2 significant risk factors (phantom limb sensation intensity and age); and (3) on the other hand, for RLP, risk factors are different: presence of pain before amputation and level of amputation (in addition to the same protective factors).

CONCLUSION

These results suggest different neurobiological mechanisms to explain PLP and RLP intensity. While PLP risk factors seem to be related to maladaptive plasticity, since phantom sensation and older age are associated with more pain, RLP risk factors seem to have components leading to neuropathic pain, such as the amount of neural lesion and previous history of chronic pain. Interestingly, the phantom movement appears to be protective for both phenomena.

Benchmarking Residual Limb Pain and Phantom Limb Pain in Amputees through a Patient-reported Outcomes Survey

More than 75% of major limb amputees experience chronic pain; however, data on severity and experience of pain are inconsistent. Without a benchmark using quantitative patient-reported outcomes, it is difficult to critically assess the efficacy of novel treatment strategies. Our primary objective is to report quantitative pain parameters for a large sample of amputees using the validated Patient-reported Outcomes Measurement System (PROMIS). Secondarily, we hypothesize that certain patient factors will be associated with worse pain.

METHODS

PROMIS and Numerical Rating Scales for residual limb pain (RLP) and phantom limb pain (PLP) were obtained from a cross-sectional survey of upper and lower extremity amputees recruited throughout North America via amputee clinics and websites. Demographics (gender, age, race, and education) and clinical information (cause, amputation level, and time since amputation) were collected. Regression modeling identified factors associated with worse pain scores (P < 0.05).

RESULTS

Seven hundred twenty-seven surveys were analyzed, in which 73.4% reported RLP and 70.4% reported PLP. Median residual PROMIS scores were 46.6 [interquartile range (IQR), 41-52] for RLP Intensity, 56.7 (IQR, 51-61) for RLP Behavior, and 55.9 (IQR, 41-63) for RLP Interference. Similar scores were calculated for PLP parameters: 46.8 (IQR, 41-54) for PLP Intensity, 56.2 (IQR, 50-61) for PLP Behavior, and 54.6 (IQR, 41-62) for PLP Interference. Female sex, lower education, trauma-related amputation, more proximal amputation, and closer to time of amputation increased odds of PLP. Female sex, lower education, and infection/ischemia-related amputation increased odds of RLP.

CONCLUSION

This survey-based analysis provides quantitative benchmark data regarding RLP and PLP in amputees with more granularity than has previously been reported.