Patient-centered results from a multicenter study of continuous peripheral nerve blocks and postamputation phantom and residual limb pain: secondary outcomes from a randomized, clinical trial

INTRODUCTION

We previously reported that a 6-day continuous peripheral nerve block reduces established postamputation phantom pain. To provide patients and providers with the information to best inform treatment decisions, here we reanalyze the data and present the results in a more patient-centered format. We also provide information on patient-defined clinically relevant benefits to facilitate evaluation of available studies and guide future trial design.

METHODS

The original trial enrolled participants with a limb amputation and phantom pain who were randomized to receive a 6-day continuous peripheral nerve block(s) of either ropivacaine (n=71) or saline (n=73) in a double-masked fashion. Here we calculate the percentage of each treatment group that experienced a clinically relevant improvement as defined by previous studies as well as present what the participants of our study defined as small, medium, and large analgesic improvements using the 7-point ordinal Patient Global Impression of Change scale.

RESULTS

Among patients who were given a 6-day ropivacaine infusion, 57% experienced at least a 2-point improvement on the 11-point numeric rating scale in their average and worst phantom pain 4 weeks postbaseline as compared with 26% (p<0.001) for average and 25% (p<0.001) for worst pain in patients given a placebo infusion. At 4 weeks, the percentage of participants rating their pain as improved was 53% for the active vs 30% for the placebo groups (95% CI 1.7 (1.1, 2.7), p=0.008). For all patients combined, the median (IQR) phantom pain Numeric Rating Scale improvements at 4 weeks considered small, medium, and large were 2 (0-2), 3 (2-5), and 5 (3-7), respectively. The median improvements in the Brief Pain Inventory interference subscale (0-70) associated with small, medium, and large analgesic changes were 8 (1-18), 22 (14-31), and 39 (26-47).

CONCLUSIONS

Among patients with postamputation phantom pain, a continuous peripheral nerve block more than doubles the chance of a clinically relevant improvement in pain intensity. Amputees with phantom and/or residual limb pain rate analgesic improvements as clinically relevant similarly to other chronic pain etiologies, although their smallest relevant improvement in the Brief Pain Inventory was significantly larger than previously published values.

TRIAL REGISTRATION NUMBER

NCT01824082.

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

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

Selective nerve root injection of ozone for the treatment of phantom limb pain: Three case reports

RATIONALE

Phantom limb pain (PLP) refers to a common complication following amputation, which is characterized by intractable pain in the absent limb, phantom limb sensation, and stump pain. The definitive pathogenesis of PLP has not been fully understood, and the treatment of PLP is still a great challenge. Till now, ozone injection has never been reported for the treatment of PLP.

PATIENT CONCERNS

We report 3 cases: a 68-year-old man, a 48-year-old woman, and a 46-year-old man. All of them had an amputation history and presented with stump pain, phantom limb sensation, and sharp pain in the phantom limb. Oral analgesics and local blocking in stump provided no benefits.

DIAGNOSIS

They were diagnosed with PLP.

INTERVENTIONS

We performed selective nerve root ozone injection combined with ozone injection in the stump tenderness points.

OUTCOMES

There were no adverse effects. Postoperative, PLP, and stump pain were significantly improved. During the follow-up period, the pain was well controlled.

LESSONS

Selective nerve root injection of ozone is safe and the outcomes were favorable. Ozone injection may be a new promising approach for treating PLP.

Repetitive Transcranial Magnetic Stimulation for Phantom Limb Pain in Land Mine Victims: A Double-Blinded, Randomized, Sham-Controlled Trial

We evaluated the effects of repetitive transcranial magnetic stimulation (rTMS) in the treatment of phantom limb pain (PLP) in land mine victims. Fifty-four patients with PLP were enrolled in a randomized, double-blinded, placebo-controlled, parallel group single-center trial. The intervention consisted of real or sham rTMS of M1 contralateral to the amputated leg. rTMS was given in series of 20 trains of 6-second duration (54-second intertrain, intensity 90% of motor threshold) at a stimulation rate of 10 Hz (1,200 pulses), 20 minutes per day, during 10 days. For the control group, a sham coil was used. The administration of active rTMS induced a significantly greater reduction in pain intensity (visual analogue scale scores) 15 days after treatment compared with sham stimulation (-53.38 ± 53.12% vs -22.93 ± 57.16%; mean between-group difference = 30.44%, 95% confidence interval, .30-60.58; P = .03). This effect was not significant 30 days after treatment. In addition, 19 subjects (70.3%) attained a clinically significant pain reduction (>30%) in the active group compared with 11 in the sham group (40.7%) 15 days after treatment (P = .03). The administration of 10 Hz rTMS on the contralateral primary motor cortex for 2 weeks in traumatic amputees with PLP induced significant clinical improvement in pain.

PERSPECTIVE

High-frequency rTMS on the contralateral primary motor cortex of traumatic amputees induced a clinically significant pain reduction up to 15 days after treatment without any major secondary effect. These results indicate that rTMS is a safe and effective therapy in patients with PLP caused by land mine explosions.

[Burning sensation in oral cavity--burning mouth syndrome in everyday medical practice]

Burning mouth syndrome (BMS) refers to chronic orofacial pain, unaccompanied by mucosal lesions or other evident clinical signs. It is observed principally in middle-aged patients and postmenopausal women. BMS is characterized by an intense burning or stinging sensation, typically on the tongue or in other areas of the oral mucosa. It can be accompanied by other sensory disorders such as dry mouth or taste alterations. Probably of multifactorial origin, and often idiopathic, with a still unknown etiopathogenesis in which local, systemic and psychological factors are implicated. Currently there is no consensus on the diagnosis and classification of BMS. This study reviews the literature on this syndrome, with special reference to the etiological factors that may be involved and the clinical aspects they present. The diagnostic criteria that should be followed and the therapeutic management are discussed with reference to the most recent studies.

The contribution of sympathetic mechanisms to postamputation phantom and residual limb pain: a pilot study

Postamputation pain (PAP) affects over 60% of major limb amputees. One of the main challenges in treating PAP is the difficulty involved in identifying pain mechanism(s), which pertains to both residual limb pain (RLP) and phantom limb pain (PLP). In this study, sympathetic blocks were performed on 17 major limb amputees refractory to treatment, including 2 placebo-controlled blocks done for bilateral amputations. One hour postinjection, mean RLP scores at rest declined from 5.2 (SD 2.8) to 2.8 (SD 2.6) (P = .0002), and PLP decreased from 5.3 (SD 3.1) to 2.3 (SD 2.1) (P = .0009). By 1 week, mean pain scores for RLP and PLP were 4.3 (SD 2.9) and 4.2 (SD 3.0), respectively. Overall, 8 of 16 (50%) patients experienced ≥50% reduction in RLP 1-hour postinjection, with the beneficial effects being maintained at 1 and 8 weeks in 4 and 1 patient(s), respectively. For PLP, 8 of 15 (53%) patients obtained ≥50% decrease in pain 1-hour postblock, with these numbers decreasing to 2 patients at both 1 and 8 weeks. In the 2 bilateral amputees who received controlled injections, mean PLP and RLP at rest scores went from 4.0 and 3.3 to 4.0 and 2.5 1-hour postblock, respectively, on the placebo side. On the treatment side, mean PLP and RLP scores decreased from 7.5 and 6.5, respectively, to 0.

PERSPECTIVE

The results of this study suggest that sympathetic mechanisms play a role in PLP and to a lesser extent, RLP, but that blocks confer long-term benefits in only a small percentage of patients.

Development of an implantable transverse intrafascicular multichannel electrode (TIME) system for relieving phantom limb pain

Phantom limb pain frequently follows amputation. Currently there is no fully effective treatment available. Our aim is to develop an innovative Human Machine Interface (HMI) where we apply multi-channel microstimulation to the nerve stump of an amputee subject to manipulate the phantom limb sensations and explore the possibility of using microstimulation as a treatment for phantom limb pain.

A randomised double blind trial of the effect of pre-emptive epidural ketamine on persistent pain after lower limb amputation

Persistent pain has been reported in up to 80% of patients after limb amputation. The mechanisms are not fully understood, but nerve injury during amputation is important, with evidence for the crucial involvement of the spinal N-methyl d-aspartate (NMDA) receptor in central changes. The study objective was to assess the effect of pre-emptively modulating sensory input with epidural ketamine (an NMDA antagonist) on post-amputation pain and sensory processing. The study recruited 53 patients undergoing lower limb amputation who received a combined intrathecal/epidural anaesthetic for surgery followed by a randomised epidural infusion (Group K received racemic ketamine and bupivacaine; Group S received saline and bupivacaine). Neither general anaesthesia nor opioids were used during the peri-operative period. Pain characteristics were assessed for 12 months. The primary endpoint was incidence and severity of post-amputation pain. Persistent pain at one year was much less in both groups than in comparable studies, with no significant difference between groups (Group K=21% (3/14) and 50% (7/14); and Group S=33% (5/15) and 40% (6/15) for stump and phantom pain, respectively). Post-operative analgesia was significantly better in Group K, with reduced stump sensitivity. The intrathecal/epidural technique used, with peri-operative sensory attenuation, may have reduced ongoing sensitisation, reducing the overall incidence of persistent pain. The improved short-term analgesia and reduced mechanical sensitivity in Group K may reflect acute effects of ketamine on central sensitisation. Longer term effects on mood were detected in Group K that requires further study.

High-dose morphine for intractable phantom limb pain

Phantom limb pain is difficult to treat as existing therapies have limited effectiveness and what works for one person may not work for another. This makes the fact that research is ongoing and advancing even more important to many people who have this problem. We are reporting a case of intractable phantom limb pain whose pain did not respond to usual line of treatment and only high dose of morphine made the patient totally pain free.

Graded motor imagery for pathologic pain: a randomized controlled trial

BACKGROUND

Phantom limb and complex regional pain syndrome type 1 (CRPS1) are characterized by changes in cortical processing and organization, perceptual disturbances, and poor response to conventional treatments. Graded motor imagery is effective for a small subset of patients with CRPS1.

OBJECTIVE

To investigate whether graded motor imagery would reduce pain and disability for a more general CRPS1 population and for people with phantom limb pain.

METHODS

Fifty-one patients with phantom limb pain or CRPS1 were randomly allocated to motor imagery, consisting of 2 weeks each of limb laterality recognition, imagined movements, and mirror movements, or to physical therapy and ongoing medical care.

RESULTS

There was a main statistical effect of treatment group, but not diagnostic group, on pain and function. The mean (95% CI) decrease in pain between pre- and post-treatment (100 mm visual analogue scale) was 23.4 mm (16.2 to 30.4 mm) for the motor imagery group and 10.5 mm (1.9 to 19.2 mm) for the control group. Improvement in function was similar and gains were maintained at 6-month follow-up.

CONCLUSION

Motor imagery reduced pain and disability in these patients with complex regional pain syndrome type I or phantom limb pain, but the mechanism, or mechanisms, of the effect are not clear.

Remote activation of referred phantom sensation and cortical reorganization in human upper extremity amputees

Phantom limb sensation, whether painful or not, frequently occurs after peripheral nerve lesions. It can be elicited by stimulating body parts adjacent to the amputation site (referred to as phantom sensation) and it is often similar in quality to the stimulation at the remote site. The present study induced referred phantom sensations in two upper limb amputees. Neuroelectric source imaging (ESI) as well as functional magnetic resonance imaging (fMRI) was used to assess reorganization in primary somatosensory cortex (SI). Whereas recent studies found mislocalization of sensation related to stimulation mainly in regions adjacent and ipsilateral to the amputation site, we report here the elicitation of phantom sensation in the arm by stimulation in the lower body part both ipsi- and contralateral to the amputation in two arm amputees. The fMRI evaluation of one patient showed no shift in the location of the foot whereas ESI revealed major reorganization of the mouth region in primary somatosensory cortex in both patients. These data suggest that cortical structures other than SI might be contributing to the phenomenon of referred sensation. Candidate structures are the thalamus, secondary somatosensory cortex, posterior parietal cortex and prefrontal cortex.

Microelectrode findings in the thalamus in chronic pain and other conditions

Functional neurosurgery usually requires physiological corroboration of the target site, particularly by eliciting characteristic responses to stimulation, or else by microelectrode recording of single cell responses to appropriate stimuli. Understanding pain physiology with both strategies has proven elusive, particularly microelectrode recording in response to noxious or thermal stimuli. The limited experience with stimulation and recording in pain pathways of the brain will be reviewed as well as the apparently pathophysiological observations made in certain patients with neuropathic pain.

Chronic motor cortex stimulation for phantom limb pain: correlations between pain relief and functional imaging studies

Chronic motor cortex stimulation (CMCS) has provided satisfactory control of pain in patients with central or trigeminal neuropathic pain. We used this technique in 3 patients with intractable phantom limb pain after upper limb amputation. Functional magnetic resonance imaging (fMRI) correlated to anatomical MRI permitted frameless image guidance for electrode placement. Pain control was obtained for all the patients initially and the relief was stable in 2 of the 3 patients at 2 year follow-up. CMCS can be used to relieve phantom limb pain. fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication.

Reorganization of motor and somatosensory cortex in upper extremity amputees with phantom limb pain

Phantom limb pain (PLP) in amputees is associated with reorganizational changes in the somatosensory system. To investigate the relationship between somatosensory and motor reorganization and phantom limb pain, we used focal transcranial magnetic stimulation (TMS) of the motor cortex and neuroelectric source imaging of the somatosensory cortex (SI) in patients with and without phantom limb pain. For transcranial magnetic stimulation, recordings were made bilaterally from the biceps brachii, zygomaticus, and depressor labii inferioris muscles. Neuroelectric source imaging of the EEG was obtained after somatosensory stimulation of the skin overlying face and hand. Patients with phantom limb pain had larger motor-evoked potentials from the biceps brachii, and the map of outputs was larger for muscles on the amputated side compared with the intact side. The optimal scalp positions for stimulation of the zygomaticus and depressor labii inferioris muscles were displaced significantly more medially (toward the missing hand representation) in patients with phantom limb pain only. Neuroelectric source imaging revealed a similar medial displacement of the dipole center for face stimulation in patients with phantom limb pain. There was a high correlation between the magnitude of the shift of the cortical representation of the mouth into the hand area in motor and somatosensory cortex and phantom limb pain. These results show enhanced plasticity in both the motor and somatosensory domains in amputees with phantom limb pain.

Midazolam for the treatment of phantom limb pain exacerbation: preliminary reports

Phantom pain is one of the most difficult intractable pains to manage. The pain may result from the imbalance of self-sustaining neural activity that exceeds the inhibitory control. The management of acute severe exacerbation of phantom pain is extremely difficult. Midazolam acts by potentiation of gamma aminobutyric acid (GABA) and enhance the inhibitory action of glycine receptor at spinal neurons. We describe two preliminary reports of complete pain relief of severe phantom pain exacerbation by intravenous midazolam 3-5 mg.

Phantom sensations following acute pain

In human amputees with painful phantom sensations, mislocalizations of tactile stimuli to the phantom increase with the amount of cortical representational reorganization and the extent of phantom pain. A similar phenomenon was incidentally encountered in healthy subjects. For reasons unrelated to the question of mislocalization, we performed a study involving the application of experimental acute pain to the hand followed by non-noxious tactile stimulation of the ipsilateral lip. During lip stimulation, two out of six subjects spontaneously reported perceiving an additional phantom-like sensation in the hand synchronously to the non-noxious lip stimulation. Similar, although more diffuse, phantom sensations were observed in two out of seven additional subjects who were then tested specifically for this effect. The observation is compatible with a pain-induced hyperresponsiveness of the cortical hand area to somatotopically adjacent inputs from the lip. This suggests that, even in the absence of deafferentation, pain can lead to a representational reorganization.

Optimal treatment of phantom limb pain in the elderly

Phantom limb and stump pain is a common sequela of amputation. In geriatric patients with an amputated limb and multiple other illnesses, drug therapy may be problematic and invasive techniques may be risky. Interactions between pathophysiological mechanisms in the peripheral and central nervous systems may be responsible for the initiation and maintenance of chronic phantom limb and stump pain. These mechanisms include: (i) peripheral damage to nociceptive fibres and dorsal root ganglion cells, which acquire abnormal sensitivity to mechanical, thermal and chemical stimuli; (ii) the prolonged sensitisation of central nociceptive 'second order' neurons in the dorsal horn of the spinal cord, which become hyperexcitable and start responding to nonnoxious stimuli; and (iii) the degeneration of nociceptive neurons, which may trigger the anatomical sprouting of low threshold mechanosensitive terminals to form connections with central nociceptive neurons. This may subsequently induce functional synaptic reorganisation in the dorsal horn. The provision of a pain-free perioperative interval using regional anaesthetic techniques is likely to reduce the incidence of phantom limb pain. The therapy of manifest pain is difficult, and treatment should start as soon as possible to prevent chronic pain. In the acute state, the infusion of calcitonin and oral opioid analgesics have proven to be helpful, while established phantom limb pain may respond to antidepressants, anticonvulsants and drugs that mimic or enhance gamma-aminobutyric acid function. Pharmacological treatment should be combined with transcutaneous electrical nerve stimulation, sympathetic blockade and psychotherapy. In addition, new therapeutic strategies are now being tested; examples include capsaicin, new anticonvulsants and N-methyl-D-aspartate antagonists. Patients with severe pain should be referred to a pain specialist to ensure optimal and timely interventional pain management.

Psychomotor agitation following gabapentin use in brain injury

Gabapentin, an anticonvulsant structurally related to gamma-aminobutyric acid (GABA) was recently reported to be effective in pain associated with reflex sympathetic dystrophy (RSD) and in pain associated with neuropathy. Yet, to our knowledge, the use of gabapentin for neuropathic pain in the presence of cognitive impairment has not been reported. In this report, we describe two patients (one with a traumatic brain injury, one with a putative acquired brain injury) who presented to a neurorehabilitation unit complaining of pain that was diagnosed as neurologically mediated. Within one week of receiving a daily 900 mg dose of gabapentin, both patients complained of heightened anxiety and restlessness. Correspondingly, each reported a diminution of psychological symptoms within 48 hours of gabapentin cessation. These two cases suggest that gabapentin may cause agitation in cognitive impaired patients. Physicians treating brain-injured patients and prescribing gabapentin for neuropathic pain may wish to closely monitor patients for similar signs of restlessness or anxiety.

[Differential combined drug therapy of phantom pain syndrome after amputation of extremity]

The authors consider that failures in the treatment of phantom pain syndrome (PPS) are explained by the lack of individual approach to the clinical manifestations of the syndrome. Three main clinical forms of PPS are distinguished using McGillow's questionnaire: causalgic, neuralgic, and spastic. Differentiated therapy for each form is proposed: combinations of amitriptyline, propranolol, and phenazepam for the first form, carbamazepine, propranolol, and phenazepam for the second, and tizanidine monotherapy for the third form. The efficacy of such therapy is approximately 75.2%, incidence of relapses during a year's follow up 12.4%.

Regional anaesthesia for repeat Caesarean section in a patient with phantom limb pain

The triggering of phantom limb pain by subarachnoid or epidural anaesthesia has been well described leading to the suggestion that neuraxial regional anaesthesia is relatively contraindicated in lower limb amputees. We report our experience of the provision of anaesthesia for repeat Caesarean section on two occasions in such a patient. Intrathecal fentanyl and morphine supplementation of bupivacaine successfully abolished peri-operative phantom limb pain, whereas epidural anaesthesia was associated with recurrence of phantom limb pain upon regression of the block.

Rogerian science, phantoms, and therapeutic touch: exploring potentials

Traditional medical approaches to the treatment of potentially distressing phantom pain and sensations have been inconsistent in their success. In this article, the subject of phantom pain and sensations is explored and reconceptualized according to Martha Rogers' science of unitary human beings. Emergent perspectives, illustrated by a series of short case studies, suggest that such a reconceptualization and particularly the use of therapeutic touch may have a significant impact on positive human field image patterning.

Phantom pain

The natural course of postamputation phenomena in cancer patients, including phantom pain, is poorly understood. Phantom pain may be disabling in a significant minority of patients undergoing amputation for malignancy. Due to advances in pain research, the pathophysiology of phantom pain is better understood. Both peripheral and central nervous system mechanisms play a role. Therapeutic options for persistent phantom pain are currently limited. Research into pharmacologic prevention strategies may yield more effective methods. A multidisciplinary care approach is designed to facilitate physical and psychological recovery after loss of a body part. Medical decision trees pertaining to cancer amputation are presented. Oncologists should be familiar with what is known about phantom pain in order to counsel patients and make appropriate referrals for comprehensive care.

Auricular transcutaneous electrical nerve stimulation (TENS) reduces phantom limb pain

The present paper evaluates the efficacy of low frequency, high intensity auricular transcutaneous electrical nerve stimulation (TENS) for the relief of phantom limb pain. Auricular TENS was compared with a no-stimulation placebo condition using a controlled crossover design in a group of amputees with (1) phantom limb pain (Group PLP), (2) nonpainful phantom limb sensations (Group PLS), and (3) no phantom limb at all (Group No PL). Small, but significant, reductions in the intensity of nonpainful phantom limb sensations were found for Group PLS during the TENS but not the placebo condition. In addition, 10 min after receiving auricular TENS, Group PLP demonstrated a modest, yet statistically significant decrease in pain as measured by the McGill Pain Questionnaire. Ratings of mood, sleepiness, and anxiety remained virtually unchanged across test occasions and sessions, indicating that the decrease in pain was not mediated by emotional factors. Further placebo-controlled trials of auricular TENS in patients with phantom limb pain are recommended in order to evaluate the importance of electrical stimulation parameters such as pulse width and rate, and to establish the duration of pain relief.

Phantom limbs and the concept of a neuromatrix

The phenomenon of a phantom limb is a common experience after a limb has been amputated or its sensory roots have been destroyed. A complete break of the spinal cord also often leads to a phantom body below the level of the break. Furthermore, a phantom of the breast, the penis, or of other innervated body parts is reported after surgical removal of the structure. A substantial number of children who are born without a limb feel a phantom of the missing part, suggesting that the neural network, or 'neuromatrix', that subserves body sensation has a genetically determined substrate that is modified by sensory experience.

[Post-amputation pain in patients with vascular diseases: clinical characteristics]

On the base of a study performed on 34 patients who underwent an amputation since 1981 to 1987, we evaluated the incidence of postamputation syndromes such as phantom limb, phantom pain, stump pain analyzing their variations during 6 years. The patients were divided in 6 groups according to the time gone by from the date of operation. The results reveals a not significant decrease of incidence of postamputation syndromes even though their frequency and intensity show a relative improvement.

Common pain syndromes and their management

Every anaesthetist can apply knowledge or skills used in routine clinical practice to make a significant contribution to the management and control of acute and chronic pain. This is true whether the pain arises from malignant or non-malignant causes.

Stump and phantom limb pain

Recent literature suggests that phantom pain and stump pain have closely related physiologic mechanisms and that treatments frequently overlap. Decreased blood flow in the residual limb is related to burning and tingling phantom and stump pain, whereas spasms in major muscles of the residual limb precede cramping phantom and stump pain. There is little support for psychological mechanisms underlying the vast majority of chronic phantom and stump pain problems, but these mechanisms can exacerbate both acute and chronic pain. It is critically important to educate patients about the process of amputation and the physiologic mechanisms of phantom sensation and pain in order to minimize magnification of pain due to stress. Acute stump pain usually responds well to traditional interventions based on identifying and correcting specific problems in the residual limb. Most traditional treatments for phantom pain and chronic stump pain are not effective for more than a few months. Recommended treatments are related to underlying mechanisms. For chronic phantom and stump pain, burning sensations are treated with interventions designed to increase blood flow to the residual limb, whereas cramping sensations are treated with interventions that reduce muscle spasms.

An association between phantom limb sensations and stump skin conductance during transcutaneous electrical nerve stimulation (TENS) applied to the contralateral leg: a case study

This report describes a placebo-controlled study of transcutaneous electrical nerve stimulation (TENS) applied to the contralateral lower leg and outer ears of an amputee with non-painful phantom sensations. The subject received TENS or placebo stimulation on separate sessions in which baseline periods of no stimulation alternated with periods of TENS (or placebo). Throughout the two sessions, continuous measures of stump skin conductance, surface skin temperature and phantom intensity were obtained. The results showed that TENS applied to the contralateral leg was significantly more effective than a placebo in decreasing the intensity of phantom sensations, whereas stimulation of the outer ears led to a non-significant increase. The pattern of electrodermal activity on the TENS session was consistently linear during baseline periods, indicating a progressive increase in sympathetic sudomotor activity. In contrast, during periods of electrical stimulation the pattern of electrodermal activity was consistently curvilinear indicating an initial decrease followed by an increase in sudomotor responses. Changes in stump skin conductance correlated significantly with changes in phantom sensations both in TENS and placebo sessions suggesting a relationship between sympathetic activity at the stump and paresthesias referred to the phantom. Two hypotheses are presented to account for these findings.

Concurrent variation of burning phantom limb and stump pain with near surface blood flow in the stump

Thermographic recordings of body temperature were performed on 30 consecutive amputees who reported stump and/or phantom limb pain. Each subject participated in between two and four recording sessions. Whenever possible, subjects came for recording sessions when their pain intensity was different from that of previous sessions. We found that a consistent inverse relationship occurred between intensity of pain and stump temperature relative to that of the intact limb for burning, throbbing, and tingling descriptions of both phantom and stump pain. Heat emanating from the limbs is an accurate reflection of near-surface blood flow. For subjects giving these descriptions of pain, tensing the limb was followed by a decrease in blood flow and an increase in pain. Neither of these relationships held for other descriptions of either phantom or stump pain.

Long-term use of narcotic/antidepressant medication in the management of phantom limb pain

The successful management of 5 consecutive patients with intractable phantom limb pain is described. The main therapy is a combination of a narcotic and antidepressant. Medication remained effective during the average observation time of 22 months. There were no signs of habituation or addiction. We conclude that narcotics can be safely and successfully utilized for long-term management of phantom limb pain.

[Treatment of deafferentation pain by high-frequency intervention on the dorsal root entry zone]

From August 1980 to May 1981, high-frequency lesions of the dorsal root entry zone of the spinal cord were performed on 35 patients with chronic deafferentiation pains. Among them were 15 patients with traumatic transverse cord lesions, 5 with non-traumatic transverse lesions and 7 with cervical root tears or traumatic brachial plexus lesions, 6 with stump or phantom pain after amputation, and 1 each with sciatic paralysis or spinal arachnopathy. Treatment results were best in complete transverse lesions, cervical root avulsion and brachial plexus lesion, less so for stump or phantom pain of the lower extremities. It failed in patients with sciatic-nerve lesion and arachnopathy. Thus best results are to be expected if the method is limited to genuine deafferentiation pain.