Analysis of Natural Antibodies during the Development of Phantom Pain Syndrome

We determined natural antibodies (n-Abs) to the regulators of the main systems of biochemical homeostasis: β-endorphin, serotonin, dopamine, histamine, orphanin, angiotensin, GABA, glutamate, bradykinin, vasopressin, thrombin, and α-2-macroglobulin in individuals with phantom pain syndrome (PPS), resulting from amputation after injury. It was established that each patient has an individual immunoprofile, but for all of them there was a significant increase in the level of antibodies to serotonin, histamine, and angiotensin, which reflect the chronicity of the pain syndrome and do not depend on the self-assessment of the severity of PPS. Determination of the role of regulators of biochemical homeostasis in the development of phantom pain showed that, at high, moderate, and weak severity of PPS, the biogenic amine and angiotensinergic systems are activated. A decrease in PPS intensity normalizes deviations in all immunological parameters. The levels of n-Abs for the pain (β-endorphin) and analgesic (orphanin) systems are significant only at low PPS. Monitoring the individual profile of n-Abs to endogenous regulators allows us to obtain an objective picture of the pain status of the patient's body.

Lower jaw-to-forepaw rapid and delayed reorganization in the rat forepaw barrel subfield in primary somatosensory cortex

We used the forepaw barrel subfield (FBS), that normally receives input from the forepaw skin surface, in rat primary somatosensory cortex as a model system to study rapid and delayed lower jaw-to-forepaw cortical reorganization. Single and multi-unit recording from FBS neurons was used to examine the FBS for the presence of "new" lower jaw input following deafferentations that include forelimb amputation, brachial plexus nerve cut, and brachial plexus anesthesia. The major findings are as follows: (1) immediately following forelimb deafferentations, new input from the lower jaw becomes expressed in the anterior FBS; (2) 7-27 weeks after forelimb amputation, new input from the lower jaw is expressed in both anterior and posterior FBS; (3) evoked response latencies recorded in the deafferented FBS following electrical stimulation of the lower jaw skin surface are significantly longer in both rapid and delayed deafferents compared to control latencies for input from the forepaw to reach the FBS or for input from lower jaw to reach the LJBSF; (4) the longer latencies suggest that an additional relay site is imposed along the somatosensory pathway for lower jaw input to access the deafferented FBS. We conclude that different sources of input and different mechanisms underlie rapid and delayed reorganization in the FBS and suggest that these findings are relevant, as an initial step, for developing a rodent animal model to investigate phantom limb phenomena.

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.

Feasibility of Magnetic Resonance-Guided High-Intensity-Focused Ultrasound (MRgHIFU) Ablation of Stump Neuromas for the Relief of Chronic Postamputation Neuropathic Pain

Up to 70% of limb amputees develop chronic postamputation neuropathic pain (CPANP) which includes phantom pain and residual limb neuropathic pain due to neuroma formation. CPANP often requires invasive procedures aimed at neuroma ablation. Five amputees received 6 noninvasive magnetic resonance-guided high-intensity-focused ultrasound MRgHIFU treatments ExAblate®, Insightec, Tirat-Carmel, Israel). Although ablative temperature (>65°C) at the neuroma was reached in only 1 patient, pain intensity dropped from 5.7 at baseline to 4.3 and back to 5.6 at 3 and 6 month follow-up. Post-treatment bone necrosis was demonstrated in 1 patient. Although no firm conclusion about the effectiveness of MRgHIFU for CPANP could be drawn, further studies are warranted.

Altered intra- and inter-network brain functional connectivity in upper-limb amputees revealed through independent component analysis

Although cerebral neuroplasticity following amputation has been observed, little is understood about how network-level functional reorganization occurs in the brain following upper-limb amputation. The objective of this study was to analyze alterations in brain network functional connectivity (FC) in upper-limb amputees (ULAs). This observational study included 40 ULAs and 40 healthy control subjects; all participants underwent resting-state functional magnetic resonance imaging. Changes in intra- and inter-network FC in ULAs were quantified using independent component analysis and brain network FC analysis. We also analyzed the correlation between FC and clinical manifestations, such as pain. We identified 11 independent components using independent component analysis from all subjects. In ULAs, intra-network FC was decreased in the left precuneus (precuneus gyrus) within the dorsal attention network and left precentral (precentral gyrus) within the auditory network; but increased in the left Parietal_Inf (inferior parietal, but supramarginal and angular gyri) within the ventral sensorimotor network, right Cerebelum_Crus2 (crus II of cerebellum) and left Temporal_Mid (middle temporal gyrus) within the ventral attention network, and left Rolandic_Oper (rolandic operculum) within the auditory network. ULAs also showed decreased inter-network FCs between the dorsal sensorimotor network and ventral sensorimotor network, the dorsal sensorimotor network and right frontoparietal network, and the dorsal sensorimotor network and dorsal attention network. Correlation analyses revealed negative correlations between inter-network FC changes and residual limb pain and phantom limb pain scores, but positive correlations between inter-network FC changes and daily activity hours of stump limb. These results show that post-amputation plasticity in ULAs is not restricted to local remapping; rather, it also occurs at a network level across several cortical regions. This observation provides additional insights into the plasticity of brain networks after upper-limb amputation, and could contribute to identification of the mechanisms underlying post-amputation pain.

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.

Post-amputation pain among lower limb amputees in a tertiary care hospital in Jeddah, Saudi Arabia: A retrospective study

OBJECTIVES

To estimate the prevalence of post- amputation pain among lower-limb amputees and its burden on their lives.

METHODS

A retrospective patients record review of lower limb amputation surgeries was carried out at King Abdulaziz University Hospital, Jeddah, Saudi Arabia, between 2008-2019. e collected data included: patients demographics, surgical operations, chronic pain characteristics, functional impairment, and treatment.

RESULTS

A total of 645 lower-limb amputations carried out on 509 patients, 104 (20.4%) patients had more than one amputation surgery carried out, and 40 (7.9%) patients having bilateral amputations. The estimated prevalence of chronic post-amputation pain among the lower-limb amputees was approximately 61.5%. Persistent postoperative neuropathic pain was the most common type of pain following amputation, followed by residual limb pain, then phantom limb pain. The most common cause of amputation was diabetes and its related complications (76%). The mean age at surgery was 57.46±12.02 years. Although diabetes was a common comorbid illness (95.6%), it had no correlation with the development of chronic post-amputation pain. However, peripheral vascular disease had a strong association (p=0.009), especially with the development of phantom limb pain (54.5%; p=0.016). The most common reason for functional impairment among the amputees was disability (52.7%), while only 6.6% said it was secondary to pain.

CONCLUSION

Post-amputation pain is one of the major consequences of amputation. Pain was poorly managed among these patients. Special considerations should be obtained to manage these patients' pain and reduce their suffering.

Parietal Lobe Reorganization and Widespread Functional Connectivity Integration in Upper-Limb Amputees: A rs-fMRI Study

The right parietal lobe plays an important role in body image, and disorders of body image emerge after lesions in the parietal lobe or with parietal lobe epilepsy. Body image disorder also often accompanies upper-limb amputation, in which the patient misperceives that their missing limb is still part of their body. Cortical reorganization is known to occur after upper-limb amputation, but it is not clear how widespread and to what degree functional connectivity (FC) is reorganized post-amputation, nor whether such changes might be related to misperceptions of body image. Twenty-four subjects who had a traumatically upper-limb amputees (ULAs) and 24 age-matched healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans. Regions of interest (ROIs) in the right superior parietal gyrus (SPG_R) and right inferior parietal lobule (IPL_R) were defined using BrainNet Viewer. We calculated the amplitude of low-frequency fluctuations (ALFF) in ROIs and correlated the ROI mean amplitude of low-frequency fluctuations (mALFF) and mean scores on the phantom limb sensation (PLS) scale and beck depression index (BDI). We also calculated ROIs and whole-brain FC. Compared to the HC group, we observed significantly increased activation (mALFF) in ROIs of the ULA group. Moreover, correlation analyses revealed a significant positive correlation between ROI mALFF and scores on the PLS. There was a significant negative correlation between the SPG_R mALFF and BDI scores. Seed-based, whole-brain FC analysis revealed that FC in the ULA group significantly decreased in many brain regions across the entire brain. The right parietal lobe appears to be involved in some aspect of body awareness and depression in amputation patients. Upper-limb amputation results not only in reorganization in the local brain area formerly representing the missing limb, but also results in more widespread reorganization through FC changes in whole brain.

Cortical representations of phantom movements in lower limb amputees

Understanding how sensorimotor cortex (SMC) organization relates to limb loss has major clinical implications, as cortical activity associated with phantom hand movements has been shown to predict phantom pain reports. Critically, earlier studies have largely focused on upper limb amputees; far less is known regarding SMC activity in lower limb amputees, despite the fact that this population comprises the majority of major limb loss cases. We aimed to characterize BOLD fMRI responses associated with phantom and sound limb movements to test the hypothesis that SMC organization is preserved in individuals with lower limb loss. Individuals with unilateral or bilateral lower limb loss underwent fMRI scans as they performed simple movements of their sound or phantom limbs. We observed that voluntary movements of the sound and phantom ankles were associated with BOLD signal changes in medial and superior portions of the precentral and postcentral gyri. In both hemispheres, contralateral limb movements were associated with greater signal changes compared to ipsilateral limb movements. Hand and mouth movements were associated with distinct activation patterns localized to more lateral SMC regions. We additionally tested whether activations associated with phantom movements related to self-report assessments indexing phantom pain experiences, nonpainful phantom sensations and phantom movement capabilities. We found that responses during phantom ankle movements did not correlate with any of the composite phantom limb indices in our sample. Our collective results reveal that SMC representations of the amputated limb persist and that traditional somatotopic organization is generally preserved in individuals suffering from lower limb loss.

Percutaneous Peripheral Nerve Stimulation for the Treatment of Chronic Pain Following Amputation

Introduction

Chronic pain and reduced function are significant problems for Military Service members and Veterans following amputation. Peripheral nerve stimulation (PNS) is a promising therapy, but PNS systems have traditionally been limited by invasiveness and complications. Recently, a novel percutaneous PNS system was developed to reduce the risk of complications and enable delivery of stimulation without surgery.

Materials and Methods

Percutaneous PNS was evaluated to determine if stimulation provides relief from residual and phantom limb pain following lower-extremity amputation. PNS leads were implanted percutaneously to deliver stimulation to the femoral and/or sciatic nerves. Patients received stimulation for up to 60 days followed by withdrawal of the leads.

Results

A review of recent studies and clinical reports found that a majority of patients (18/24, 75%) reported substantial (≥50%) clinically relevant relief of chronic post-amputation pain following up to 60 days of percutaneous PNS. Reductions in pain were frequently associated with reductions in disability and pain interference.

Conclusions

Percutaneous PNS can durably reduce pain, thereby enabling improvements in quality of life, function, and rehabilitation in individuals with residual or phantom limb pain following amputation. Percutaneous PNS may have additional benefit for Military Service members and Veterans with post-surgical or post-traumatic pain.

Percutaneous 60-day peripheral nerve stimulation implant provides sustained relief of chronic pain following amputation: 12-month follow-up of a randomized, double-blind, placebo-controlled trial

INTRODUCTION

Peripheral nerve stimulation (PNS) has historically been used to treat chronic pain, but generally requires implantation of a permanent system for sustained relief. A recent study found that a 60-day PNS treatment decreases post-amputation pain, and the current work investigates longer-term outcomes out to 12 months in the same cohort.

METHODS

As previously reported, 28 traumatic lower extremity amputees with residual and/or phantom limb pain were randomized to receive 8 weeks of PNS (group 1) or 4 weeks of placebo followed by a crossover 4 weeks of PNS (group 2). Percutaneous leads were implanted under ultrasound guidance targeting the femoral and sciatic nerves. During follow-up, changes in average pain and pain interference were assessed using the Brief Pain Inventory-Short Form and comparing with baseline.

RESULTS

Significantly more participants in group 1 reported ≥50% reductions in average weekly pain at 12 months (67%, 6/9) compared with group 2 at the end of the placebo period (0%, 0/14, p=0.001). Similarly, 56% (5/9) of participants in group 1 reported ≥50% reductions in pain interference at 12 months, compared with 2/13 (15%, p=0.074) in group 2 at crossover. Reductions in depression were also statistically significantly greater at 12 months in group 1 compared with group 2 at crossover.

CONCLUSIONS

This work suggests that percutaneous PNS delivered over a 60-day period may provide significant carry-over effects including pain relief, potentially avoiding the need for a permanently implanted system while enabling improved function in patients with chronic pain.

TRIAL REGISTRATION NUMBER

NCT01996254.

Quality of life after amputation in patients with advanced complex regional pain syndrome: a systematic review

The majority of included studies (8 out of 11, n = 54) supported the concept of considering amputation for selected, unresponsive cases of complex regional pain syndrome (CRPS) as a justifiable alternative to an unsuccessful multimodality nonoperative option.Of patients who underwent amputation, 66% experienced improvement in quality of life (QOL) and 37% were able to use a prosthesis, 16% had an obvious decline in QOL and for 12% of patients, no clear details were given, although it was suggested by authors that these patients also encountered deterioration after amputation.Complications of phantom limb pain, recurrence of CRPS and stump pain were predominant risks and were noticed in 65%, 45% and 30% of cases after amputation, respectively and two-thirds of patients were satisfied.Amputation can be considered by clinicians and patients as an option to improve QOL and to relieve agonizing, excruciating pain of severe, resistant CRPS at a specialized centre after multidisclipinary involvement but it must be acknowledged that evidence is limited, and the there are risks of aggravating or recurrence of CRPS, phantom pain and unpredictable consequences of rehabilitation.Amputation, if considered for resistant CRPS, should be carried out at specialist centres and after MDT involvement before and after surgery. It should only be considered if requested by patients with poor quality of life who have failed to improve after multiple treatment modalities.Further high quality and comprehensive research is needed to understand the severe form of CRPS which behaves differently form less severe stages. Cite this article: EFORT Open Rev 2019;4:533-540. DOI: 10.1302/2058-5241.4.190008.

Functional rehabilitation of a person with transfemoral amputation through guided motor imagery: a case study

Background: Motor imagery (MI) is a mental technique, absent of physical movement, to foster movement patterns and relieve pain via a training model enacting the brain before the body. This case study assessed MI's efficacy in decreasing phantom limb pain and attaining functional gait and balance after lower extremity amputation. Description: The participant was a 71-year-old female with a transfemoral amputation seven years prior. She required a standard walker for ambulation. The participant underwent three sessions per week for four weeks of MI intervention, with immediate, post-test, and 1-week retention testing involving subjective and functional assessments. Intervention sessions involved quiet sitting with eyes closed while listening to the MI script. The scripts focused on functional movement patterns and tasks that were relevant to the participant, such as walking, balancing, and reaching. Each session's script focused on a different task. These scripts guided her through proper action and biomechanics of the skills to imagine herself moving safely and functionally. Outcomes: Short Form Berg Balance Scale and Tinetti Performance Oriented Mobility Assessment scores demonstrated clinically important and sustained improvement. Further, the participant reported decreased phantom limb pain and could walk a short distance independently for the first time in seven years. Discussion: MI is a time- and cost-effective, low-risk treatment option that decreased phantom pain and improved balance and functional gait in an individual with an amputation. The use of MI as an intervention for the rehabilitation of persons with amputation must be further examined.

Percutaneous peripheral nerve stimulation for the treatment of chronic neuropathic postamputation pain: a multicenter, randomized, placebo-controlled trial

BACKGROUND AND OBJECTIVES

Chronic neuropathic pain is a common challenging condition following amputation. Recent research demonstrated the feasibility of percutaneously implanting fine-wire coiled peripheral nerve stimulation (PNS) leads in proximity to the sciatic and femoral nerves for postamputation pain. A multicenter, double-blinded, randomized, placebo-controlled study collected data on the safety and effectiveness of percutaneous PNS for chronic neuropathic pain following amputation.

METHODS

Twenty-eight lower extremity amputees with postamputation pain were enrolled. Subjects underwent ultrasound-guided implantation of percutaneous PNS leads and were randomized to receive PNS or placebo for 4 weeks. The placebo group then crossed over and all subjects received PNS for four additional weeks. The primary efficacy endpoint evaluated the proportion of subjects reporting ≥50% pain reduction during weeks 1-4.

RESULTS

A significantly greater proportion of subjects receiving PNS (n=7/12, 58%, p=0.037) demonstrated ≥50% reductions in average postamputation pain during weeks 1-4 compared with subjects receiving placebo (n=2/14, 14%). Two subjects were excluded from efficacy analysis due to eligibility changes. Significantly greater proportions of PNS subjects also reported ≥50% reductions in pain (n=8/12, 67%, p=0.014) and pain interference (n=8/10, 80%, p=0.003) after 8 weeks of therapy compared with subjects receiving placebo (pain: n=2/14, 14%; pain interference: n=2/13, 15%). Prospective follow-up is ongoing; four of five PNS subjects who have completed 12-month follow-up to date reported ≥50% pain relief.

CONCLUSIONS

This work demonstrates that percutaneous PNS therapy may provide enduring clinically significant pain relief and improve disability in patients with chronic neuropathic postamputation pain.

TRIAL REGISTRATION NUMBER

NCT01996254.

Efficacy and safety of epidural, continuous perineural infusion and adjuvant analgesics for acute postoperative pain after major limb amputation - a systematic review

BACKGROUND AND AIMS

Treatment of pain following major limb amputations is often a clinical challenge in a patient population consisting mainly of elderly with underlying diseases. Literature on management of acute post-amputation pain is scarce. We performed a systematic review on this topic to evaluate the efficacy and safety of analgesic interventions for acute pain following major limb amputation.

METHODS

A literature search was performed in PubMed, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews using the following key words: [(amputation) AND (pain OR analgesi* OR pain relief)] AND (acute OR postoperative). Randomized controlled studies (RCTs) and observational studies investigating treatment of acute pain following major amputations for any indication (peripheral vascular disease, malignant disease, trauma) were included. The review was performed according to the standards described in the PRISMA statement. The Cochrane quality assessment tool was used to evaluate the risk of bias in the RCTs.

RESULTS

Nineteen studies with total of 949 patients were included. The studies were generally small and heterogeneous on outcomes, study designs and quality. There were 16 studies on epidural or continuous perineural analgesia (CPI). Based on five RCTs (n=268) and two observational studies (n=49), epidural analgesia decreased the intensity of acute stump pain as compared to systemic analgesics, during the first 24 h after the operation. Based on one study epidural analgesia caused more adverse effects like sedation, nausea and motor block than continuous perineural local anesthetic infusion. Based on one RCT (n=21) and eight observational studies (n=501) CPI seemed to decrease opioid consumption as compared to systemic analgesics only, on the first three postoperative days, and was well tolerated. Only three trials investigated systemic analgesics (oral memantine, oral gabapentine, iv ketamine). Ketamine did not decrease acute pain or opioid consumption after amputation as compared to other systemic analgesics. Gabapentin did not decrease acute pain when combined to epidural analgesia as compared to epidural analgesia and opioid treatment, and caused adverse effects.

CONCLUSIONS

The main finding of this systematic review is that evidence regarding pain management after major limb amputation is very limited. Epidural analgesia may be effective, but firm evidence is lacking. Epidural causes more adverse effects than CPI. The results on efficacy of CPI are indecisive. The data on adjuvant medications combined to epidural analgesia or CPI is limited. Studies on efficacy and adverse effects of systemic analgesics for amputation pain, especially concentrating on elderly patients, are needed.

Motor Control and Sensory Feedback Enhance Prosthesis Embodiment and Reduce Phantom Pain After Long-Term Hand Amputation

We quantified prosthesis embodiment and phantom pain reduction associated with motor control and sensory feedback from a prosthetic hand in one human with a long-term transradial amputation. Microelectrode arrays were implanted in the residual median and ulnar arm nerves and intramuscular electromyography recording leads were implanted in residual limb muscles to enable sensory feedback and motor control. Objective measures (proprioceptive drift) and subjective measures (survey answers) were used to assess prosthesis embodiment. For both measures, there was a significant level of embodiment of the physical prosthetic limb after open-loop motor control of the prosthesis (i.e., without sensory feedback), open-loop sensation from the prosthesis (i.e., without motor control), and closed-loop control of the prosthesis (i.e., motor control with sensory feedback). There was also a statistically significant reduction in reported phantom pain after experimental sessions that included open-loop nerve microstimulation, open-loop prosthesis motor control, or closed-loop prosthesis motor control. The closed-loop condition provided no additional significant improvements in phantom pain reduction or prosthesis embodiment relative to the open-loop sensory condition or the open-loop motor condition. This study represents the first long-term (14-month), systematic report of phantom pain reduction and prosthesis embodiment in a human amputee across a variety of prosthesis use cases.

Loss of Synaptic Tagging in the Anterior Cingulate Cortex after Tail Amputation in Adult Mice

Anterior cingulate cortex (ACC) is known to play important roles in key brain functions such as pain perception, cognition, and emotion. Different forms of homosynaptic plasticity such as long-term potentiation (LTP) and long-term depression have been studied in ACC synapses. However, heterosynaptic plasticity such as synaptic tagging has not been reported. Here, we demonstrate synaptic tagging in the ACC of adult male mice by using a 64-channel multielectrode array recording system. Weak theta burst stimulation (TBS), normally inducing early-phase LTP or No-LTP in most of the activated channels, produced late phase-LTP (L-LTP) in a majority of channels when a strong TBS was applied earlier to a separate input within a certain time window. Similar to hippocampus, synaptic tagging in the ACC depends on the synthesis of new proteins. Tail amputation-induced peripheral injury caused a loss of this heterosynaptic L-LTP and occluded strong TBS-evoked L-LTP as well. Together, we provide the first report of the synaptic tagging-like phenomenon in the ACC of adult mice, and the loss of synaptic tagging to amputation may contribute to injury-related cognitive changes and phantom limb sensation and pain.SIGNIFICANCE STATEMENT ACC is an important cortical region involved in many brain functions. Previous studies have dissected the molecular mechanism of multiple types of homosynaptic plasticity of ACC synapses. Here, we report a novel form of heterosynaptic plasticity occurring in the ACC. This newly identified, protein synthesis-dependent neocortical synaptic tagging is sensitive to peripheral tail amputation injury and may provide basic mechanisms for synaptic pathophysiology of phantom pain and related cognitive changes.

Evaluation of treatment of psychiatric morbidity among limb amputees

BACKGROUND

The sudden jolt of becoming an amputee brings with it the realization of loss of independence and self-built psychological and physical security. Advances in the field of prosthesis give the individual hope for better future, but the presence of psychological morbidity is a hurdle to be crossed in the road to satisfactory rehabilitation.

AIM

This study aimed to assess the psychiatric morbidity in amputees and the response to treatment.

MATERIALS AND METHODS

One hundred newly amputated soldiers were assessed by means of clinical interview, General Health Questionnaire, Impact of Event Scale, Hospital Anxiety Depression Scale, McGill Pain Questionnaire, and Dallas Pain Questionnaire. Individuals were treated with appropriate medications and psychotherapy, and response to treatment was assessed.

RESULTS

Psychiatric disorders were diagnosed in 66% including adjustment disorders (40%), depressive episode (20%), and posttraumatic stress disorder (6%). Phantom sensation and phantom pain were noted in 72% and 64% of participants, respectively. More psychiatric disorders and phantom sensation were found in the early months after amputation. Psychiatric morbidity was associated with negative body image, distressing pain, and restriction of activities of daily life. Treatment produced complete remission of symptoms in 65.15% of individuals suffering from psychiatric disorders and statistically significant reduction in the scores of psychiatric rating scales.

CONCLUSIONS

There is a high prevalence of psychiatric morbidity among amputees. Psychiatric treatment produces significant improvement in the psychological well-being of amputees and underlines the need to focus on the psychological rehabilitations of the amputee apart from physical rehabilitation.

Tinnitus: Prospects for Pharmacological Interventions With a Seesaw Model

Chronic tinnitus, the perception of lifelong constant ringing in ear, is one capital cause of disability in modern society. It is often present with various comorbid factors that severely affect quality of life, including insomnia, deficits in attention, anxiety, and depression. Currently, there are limited therapeutic treatments for alleviation of tinnitus. Tinnitus can involve a shift in neuronal excitation/inhibition (E/I) balance, which is largely modulated by ion channels and receptors. Thus, ongoing research is geared toward pharmaceutical approaches that modulate the function of ion channels and receptors. Here, we propose a seesaw model that delineates how tinnitus-related ion channels and receptors are involved in homeostatic E/I balance of neurons. This review provides a thorough account of our current mechanistic understanding of tinnitus and insight into future direction of drug development.

Representation of Multiple Body Parts in the Missing-Hand Territory of Congenital One-Handers

Individuals born without one hand (congenital one-handers) provide a unique model for understanding the relationship between focal reorganization in the sensorimotor cortex and everyday behavior. We previously reported that the missing hand’s territory of one-handers becomes utilized by its cortical neighbor (residual arm representation), depending on residual arm usage in daily life to substitute for the missing hand’s function [1, 2]. However, the repertoire of compensatory behaviors may involve utilization of other body parts that do not cortically neighbor the hand territory. Accordingly, the pattern of brain reorganization may be more extensive [3]. Here we studied unconstrained compensatory strategies under ecological conditions in one-handers, as well as changes in activation, connectivity, and neurochemical profile in their missing hand’s cortical territory. We found that compensatory behaviors in one-handers involved multiple body parts (residual arm, lips, and feet). This diversified compensatory profile was associated with large-scale cortical reorganization, regardless of cortical proximity to the hand territory. Representations of those body parts used to substitute hand function all mapped onto the cortical territory of the missing hand, as evidenced by task-based and resting-state fMRI. The missing-hand territory also exhibited reduced GABA levels, suggesting a reduction in connectional selectivity to enable the expression of diverse cortical inputs. Because the same body parts used for compensatory purposes are those showing increased representation in the missing hand’s territory, we suggest that the typical hand territory may not necessarily represent the hand per se, but rather any other body part that shares the functionality of the missing hand [4].

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Compensatory behavior in one-handers involves utilization of multiple body parts

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Multiple body parts benefit from increased representation in the missing-hand area

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The missing-hand area showed reduced connectional selectivity (lower GABA levels)

Amputations in Sickle Cell Disease: Case Series and Literature Review

In this study, we describe four new patients with sickle cell disease who had limb amputations. Two of the patients had sickle cell anemia [Hb S (HBB: c.20A > T) (β(S)/β(S))] with refractory leg ulcers that required amputations. The third patient had sickle cell trait with an extensive leg ulcer that was associated with epidermoid carcinoma. The fourth patient had amputations of both forearms and feet due to a misdiagnosis of dactylitis. Review of the literature showed that the indications for amputations in sickle cell disease included three distinct categories: mythical beliefs, therapeutic and malpractice. All therapeutic amputations were for severely painful, large, recalcitrant leg ulcers that failed non-interventional therapies. Amputation resulted in pain relief and better quality of life. Phantom neuropathic pain was not a major issue post-operatively. It was absent, transient or well controlled with antidepressants. Limb function was restored post-amputation with prosthetic artificial limbs, wheelchairs or crutches. Malpractice amputations were due to misdiagnosis or to cryotherapy by exposing the painful limb to ice water resulting in thrombosis, gangrene and amputation. We strongly suggest that leg amputations should be considered in the management of certain patients with severe extensive refractory leg ulcers, and topical cryotherapy should never be used to manage sickle cell pain.

A systematic review on the treatment of phantom limb pain with spinal cord stimulation

Phantom limb pain (PLP) is a challenging chronic pain syndrome to treat with pharmacologic agents being first line of management. However, when these agents fail to provide pain relief, other interventions must be considered in a clinical setting. Spinal cord stimulation (SCS) has been shown to provide analgesia in PLP, and should be considered by clinicians.

METHODS

This PRISMA systematic review analyzes the efficacy of SCS for treatment of PLP.

RESULTS

After review of 12 studies, there are mixed results to base a conclusion on.

DISCUSSION

While there is some evidence of efficacy, due to the relatively small number of patients in each study, further research is needed to demonstrate the benefits of SCS for PLP.

Cross-sectional study of alteration of phantom limb pain with visceral stimulation in military personnel with amputation

While phantom limb pain is a well-recognized phenomenon, clinical experience has suggested that the augmentation of phantom limb pain with visceral stimulation is an issue for many military personnel with amputation (visceral stimulation being the sensation of the bowel or bladder either filling or evacuating). However, the prevalence of this phenomenon is not known. The aim of this study was to investigate the prevalence of the alteration in phantom limb pain and the effect that visceral stimulation has on phantom limb pain intensity. A cross-sectional study of 75 military personnel who have lost one or both lower limbs completed a questionnaire to assess the prevalence of the alteration of phantom limb pain with visceral stimulation. Included in the questionnaire was a pain visual analog scale (VAS) graded from 0 to 10. Patients recorded the presence and intensity of phantom limb pain. They also recorded whether and how this pain altered with a need to micturate or micturition, and/or a need to defecate or defecation, again using a pain VAS. Time since amputation, level of amputation, and medications were also recorded. Patients reported a phantom limb pain prevalence of 85% with a mean VAS of 3.6. In all, 56% of patients reported a change in the severity of phantom limb pain with visceral stimuli. The mean increase in VAS for visceral stimulation was 2.5 +/- 1.6 for bladder stimulation and 2.9 +/- 2.0 for bowel stimulation. Of the patients questioned, 65% reported an improvement in symptoms over time. VAS scores were highest in the subgroup less than 6 mo postamputation. An increase in phantom limb pain with visceral stimulation is a common problem for military personnel with amputation.

The effect of electromagnetic shielding on phantom limb pain: A placebo-controlled double-blind crossover trial

BACKGROUND

Environmental electromagnetic fields influence biological systems. Evidence suggests these have a role in the experience of phantom limb pain in patients with amputations.

OBJECTIVES

This article followed a previous study to investigate the effect of electromagnetic field shielding with a specially designed prosthetic liner.

STUDY DESIGN

Randomised placebo-controlled double-blind crossover trial.

METHODS

Twenty suitable participants with transtibial amputations, phantom pain at least 1 year with no other treatable cause or pathology were requested to record daily pain, well-being, activity and hours of prosthetic use on pre-printed diary sheets. These were issued for three 2-week periods (baseline, electromagnetic shielding (verum) and visually identical placebo liners - randomly allocated).

RESULTS

Thirty-three per cent of the recruited participants were unable to complete the trial. The resulting N was therefore smaller than was necessary for adequate power. The remaining data showed that maximum pain and well-being were improved from baseline under verum but not placebo. More participants improved on all variables with verum than placebo.

CONCLUSION

Electromagnetic field shielding produced beneficial effects in those participants who could tolerate the liner. It is suggested that this might be due to protection of vulnerable nerve endings from nociceptive effects of environmental electromagnetic fields.

CLINICAL RELEVANCE

Electromagnetic field shielding with a suitable limb/prosthesis interface can be considered a useful technique to improve pain and well-being in patients with phantom limb pain.

Neural interfaces for somatosensory feedback: bringing life to a prosthesis

PURPOSE OF REVIEW

When an individual loses a limb, he/she loses touch with the world and with the people around him/her. Somatosensation is critical to the feeling of connection and control of one's own body. Decades of attempts to replace lost somatosensation by sensory substitutions have been ineffective outside of the laboratory. This review discusses important recent results demonstrating chronic somatosensory restoration through direct peripheral nerve stimulation.

RECENT FINDINGS

Stimulation of peripheral nerves results in somatosensory perception on the phantom limb. Sensations are localized to several independent and functionally relevant locations, such as the fingertips, thenar eminence, ulnar border and dorsal surface. Patterns in stimulation intensity change the perception experience by the user, opening new dimensions on neuromodulation.

SUMMARY

Neural interfaces with sophisticated stimulation paradigms create a user's perception of his/her hand to touch and manipulate objects. The pattern of intensity and frequency of stimulation is critical to the quality and intensity of perceived sensation. Restoring feeling has allowed the individuals to, 'feel [my] hand for the first time since the accident,' and 'feel [my] wife touch my hand'. Individuals using a prosthetic hand with sensation can pull cherries and grapes from the stem, open water bottles and move objects without destroying these objects - all while audio and visually deprived. After regaining sensation, phantom pain is eliminated in individuals that had frequent, sometimes debilitating, pain following limb loss. With over 5 subject-years of experience, this work is leading the evolution of a new era in prostheses. Somatosensory prosthetics as a standard procedure to augment and restore somatosensation are now within our reach.

Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation

The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Euclidian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted.

[Phantom limb pains]

With the radical experience of an amputation, the adaptation of body image is often incomplete. Some people experience phantom body perceptions, often painful and difficult to treat, after the amputation of a limb.

"Imprisoned" in pain: analyzing personal experiences of phantom pain

This article explores the phenomenon of "phantom pain." The analysis is based on personal experiences elicited from individuals who have lost a limb or live with a paralyzed body part. Our study reveals that the ways in which these individuals express their pain experience is an integral aspect of that experience. The material consists of interviews undertaken with men who are living with phantom pain resulting from a traumatic injury. The phenomenological analysis is inspired by Zahavi (J Conscious Stud 8(5-7):151-167, 2001) and Merleau-Ponty (Phenomenology of perception. Routledge and Kegan Paul, London, 1962/2000). On a descriptive level the metaphors these patients invoke to describe their condition reveal immense suffering, such as a feeling of being invaded by insects or of their skin being scorched and stripped from their body. Such metaphors express a dimension of experience concerning the self that is in pain and others whom the sufferer relates to through this pain, as well as the agony that this pain inflicts in the world of lived experience. This pain has had a profound impact on their lives and altered their relationship with self (body), others and the world. Their phantom pain has become a reminder of their formerly intact and functioning body; they describe the contrast between their past and present body as an ambiguous and disturbing experience. We conclude that these sensitive and personalized experiences of phantom pain illuminates how acts of expression--spoken pain--constitute a fundamental dimension of a first-person perspective which contribute to the field of knowledge about "phantom pain".

Phantom limb pain: an energy/trauma model

Phantom limb pain (PLP) is a form of chronic neuropathic pain that responds poorly to treatment interventions derived from the neuroanatomic understanding of pain and analgesia. Several new psychological and behavioral treatments that have proven more effective have been explained by invoking neural plasticity as their mechanism of action. Other novel treatments that are based on an "energy medicine" model also appear to be quite effective, especially when addressing the psychological trauma of the amputation itself, a factor that is generally overlooked in the standard surgical approach to limb amputation. A speculative trauma/energy model for the etiology of PLP is proposed. This model is developed in some detail, and its utility in explaining several anomalous aspects of PLP, as well as the clinical efficacy of energy therapies, is outlined. This model is proposed as a step in the development of simple and effective energy/trauma treatment protocols for this widespread and largely treatment-resistant disorder.

Postamputation pain: epidemiology, mechanisms, and treatment

Postamputation pain (PAP) is highly prevalent after limb amputation but remains an extremely challenging pain condition to treat. A large part of its intractability stems from the myriad pathophysiological mechanisms. A state-of-art understanding of the pathophysiologic basis underlying postamputation phenomena can be broadly categorized in terms of supraspinal, spinal, and peripheral mechanisms. Supraspinal mechanisms involve somatosensory cortical reorganization of the area representing the deafferentated limb and are predominant in phantom limb pain and phantom sensations. Spinal reorganization in the dorsal horn occurs after deafferentataion from a peripheral nerve injury. Peripherally, axonal nerve damage initiates inflammation, regenerative sprouting, and increased "ectopic" afferent input which is thought by many to be the predominant mechanism involved in residual limb pain or neuroma pain, but may also contribute to phantom phenomena. To optimize treatment outcomes, therapy should be individually tailored and mechanism based. Treatment modalities include injection therapy, pharmacotherapy, complementary and alternative therapy, surgical therapy, and interventions aimed at prevention. Unfortunately, there is a lack of high quality clinical trials to support most of these treatments. Most of the randomized controlled trials in PAP have evaluated medications, with a trend for short-term Efficacy noted for ketamine and opioids. Evidence for peripheral injection therapy with botulinum toxin and pulsed radiofrequency for residual limb pain is limited to very small trials and case series. Mirror therapy is a safe and cost-effective alternative treatment modality for PAP. Neuromodulation using implanted motor cortex stimulation has shown a trend toward effectiveness for refractory phantom limb pain, though the evidence is largely anecdotal. Studies that aim to prevent PA P using epidural and perineural catheters have yielded inconsistent results, though there may be some benefit for epidural prevention when the infusions are started more than 24 hours preoperatively and compared with nonoptimized alternatives. Further investigation into the mechanisms responsible for and the factors associated with the development of PAP is needed to provide an evidence-based foundation to guide current and future treatment approaches.

Cortical depression and potentiation: basic mechanisms for phantom pain

People experience the feeling of the missing body part long after it has been removed after amputation are known as phantom limb sensations. These sensations can be painful, sometimes becoming chronic and lasting for several years (or called phantom pain). Medical treatment for these individuals is limited. Recent neurobiological investigations of brain plasticity after amputation have revealed new insights into the changes in the brain that may cause phantom limb sensations and phantom pain. In this article, I review recent progresses of the cortical plasticity in the anterior cingulate cortex (ACC), a critical cortical area for pain sensation, and explore how they are related to abnormal sensory sensations such as phantom pain. An understanding of these alterations may guide future research into medical treatment for these disorders.

Atypical electrophysiological activity during pain observation in amputees who experience synaesthetic pain

There are increasing reports of people experiencing pain when observing pain in another. This describes the phenomenon of synaesthetic pain which, until recently, had been primarily reported in amputees with phantom pain. In the current study, we used electroencephalography (EEG) to investigate how amputees who experience synaesthetic pain process pain observed in another. Participants were grouped according to amputees who experience phantom and synaesthetic pain (n=8), amputees who experience phantom pain but not synaesthetic pain (n=10) and healthy controls (n=10). Participants underwent EEG as they observed still images of hands and feet in potentially painful and non-painful situations. We found that pain synaesthetes showed some reduced event-related potential (ERP) components at certain electrode sites, and reduced theta- and alpha band power amplitude at a central electrode. The finding of reduced ERP amplitude and theta band power may reflect inhibition of the processing of observed pain (e.g. avoidance/guarding as a protective strategy), and reduced alpha band power may indicate a disinhibition in control processes that may result in synaesthetic pain. These results provide the first documentation of atypical neurophysiological activity in amputees who experience synaesthetic pain when processing pain in another.

"Pulling telescoped phantoms out of the stump": manipulating the perceived position of phantom limbs using a full-body illusion

Most amputees experience phantom limbs, or the sensation that their amputated limb is still attached to the body. Phantom limbs can be perceived in the location previously occupied by the intact limb, or they can gradually retract inside the stump, a phenomenon referred to as “telescoping”.  Telescoping is relevant from a clinical point of view, as it tends to be related to increased levels of phantom pain. In the current study we demonstrate how a full-body illusion can be used to temporarily revoke telescoping sensations in upper limb amputees. During this illusion participants view the body of a mannequin from a first person perspective while being subjected to synchronized visuo-tactile stimulation through stroking, which makes them experience the mannequin’s body as their own. In Experiment 1 we used an intact mannequin, and showed that amputees can experience ownership of an intact body as well as referral of touch from both hands of the mannequin. In Experiment 2 and 3 we used an amputated mannequin, and demonstrated that depending on the spatial location of the strokes applied to the mannequin, participants experienced their phantom hand to either remain telescoped, or to actually be located below the stump. The effects were supported by subjective data from questionnaires, as well as verbal reports of the perceived location of the phantom hand in a visual judgment task. These findings are of particular interest, as they show that the temporary revoking of telescoping sensations does not necessarily have to involve the visualization of an intact hand or illusory movement of the phantom (as in the rubber hand illusion or mirror visual feedback therapy), but that it can also be obtained through mere referral of touch from the stump to the spatial location corresponding to that previously occupied by the intact hand. Moreover, our study also provides preliminary evidence for the fact that these manipulations can have an effect on phantom pain sensations.

Experimental induction of a perceived "telescoped" limb using a full-body illusion

Phantom limbs refer to the sensation that an amputated or missing limb is still attached to the body. Phantom limbs may be perceived as continuous with the stump so as to resemble a normal limb, or as “telescoped” with the more distal portion of the phantom being perceived as having withdrawn within the stump. Telescoping tends to be related to increased levels of phantom pain, making it a clinically relevant phenomenon to investigate. In the current study we show that a full-body illusion can be used to induce the sensation of a telescoped limb in healthy individuals. For the induction of the full-body illusion, participants saw the body of a mannequin from a first person perspective while being subjected to synchronized visuo-tactile stimulation through stroking. Crucially, the mannequin was missing its left hand so as to resemble an amputee. By manipulating the positioning of the strokes applied to the mannequin's stump with respect to the participants’ hand we were able to evoke the sensation of the participants’ hand being located either below the stump or, more crucially, “inside” the stump, i.e., telescoped. In three separate experiments these effects were supported by complementary subjective data from questionnaires, verbally reported perceived location of the hand, and manual pointing movements indicating hand position (proprioceptive drift). Taken together our results show that healthy individuals can experience the body of an upper limb amputee as their own, and that this can be associated with telescoping sensations. This is a theoretically important observation as it shows that ownership of an entire body can be evoked in the context of gross anatomical incongruence for a single limb, and that telescoping sensations occur as a consequence of the body representation system trying to reduce this incongruence. Furthermore, the present study might provide a new platform for future studies of the relationship between telescoping and phantom pain in amputees.

Neurologic pain syndromes in cancer patients

Painful neurological syndromes in cancer patients require comprehensive clinical assessment for their accurate diagnosis. Early diagnosis of the painful neurological syndromes in cancer patients allows the clinician to target his therapy toward preventing escalating pain, disability, and further neurological morbidity. Active rehabilitation is critically important in the management of these patients with neurological pain syndromes. Rehabilitation helps prevent further pain due to the development of secondary problems of immobility or disuse, helps the individual patient achieve his maximal level of functioning and helps each patient adapt to his/her neurological deficits.