Improvement in Health-Related Quality of Life With Spinal Cord Stimulation in Complex Regional Pain Syndrome: A Single-Center, Retrospective Study.

BACKGROUND: Complex regional pain syndrome (CRPS) can profoundly affect many aspects of everyday life. Spinal cord stimulation (SCS) is a potential therapeutic option. This retrospective, single-site evaluation explored health-related quality of life (HRQoL) in individuals with CRPS treated with SCS in our Pain Service. MATERIALS AND METHODS: All patients aged ≥18 years with fully implanted SCS for CRPS between June 2013 and January 2023 were identified from hospital records. The following data were collected: sex, age, chronic pain diagnosis, CRPS type (I or II), location of CRPS (upper or lower limb), years of CRPS before first SCS implant, SCS system, preimplant and follow-up scores for HRQoL (euroqol 5 dimensions 3 levels [EQ-5D-3L] index score), average pain, worst pain and the influence of pain on aspects of everyday life (all numerical rating scale [NRS]), patient and clinician global impression of change at follow-up, and the occurrence and reasons for revisions and explants. An intention-to-treat approach was used and data statistically analyzed. RESULTS: The final cohort comprised 83 patients (46 women), with a median (minimum, maximum) follow-up duration of 29 months (seven, 72). There were statistically and clinically significant improvements in HRQoL, despite relatively low pain response rates. The pain response rate was 34% (reduction of ≥30% in average pain NRS); the pain remission rate was 13% (average pain score ≤3 NRS), and all patients had preimplant EQ-5D-3L index values below the population norm of 0.82. However, 60% of patients reported EQ-5D-3L index scores greater than the published minimally important difference of 0.074, and scores were better at follow-up than at preimplant (p < 0.001); 44% of patients and 41% of clinicians reported improved symptoms at the most recent follow-up. Explants occurred in eight of 83 patients (10%). CONCLUSIONS: Patients had meaningful improvements in HRQoL, which is a key outcome in ascertaining the overall outcome of SCS in CRPS. Randomized controlled clinical trials should build on the findings to improve understanding of the benefits and risks of treating CRPS with SCS.

[Effectiveness of inpatient interdisciplinary multimodal pain therapy (IMPT) in patients with complex regional pain syndrome (CRPS) : A retrospective study]. / Wirksamkeit einer interdisziplinären multimodalen stationären Schmerztherapie (IMST) bei Patienten mit komplexem regionalem Schmerzsyndrom (CRPS) : Eine retrospektive Studie.

BACKGROUND: The primary symptom of complex regional pain syndrome (CRPS) is pain. Interdisciplinary multimodal pain therapy (IMPT) is the gold standard of treatment. The purpose of this study was to identify the beneficial effect of inpatient IMPT on pain level, sensation, perception and impairment in patients with CRPS. QUESTION: The aim of the present study was to examine the effect of full-term IMPT on pain intensity, pain perception, pain processing, and pain impairment in patients with CRPS. METHODS: In 265 patients with CRPS, pain level was retrospectively assessed by the numeric rating scale for pain (NRS), the Pain Perception Scale (SES) and the Pain Management Questionnaire (FESV) at the beginning and end of IMPT. RESULTS: There was a significant reduction in the average and highest pain level on the NRS, a significant improvement in the affective experience of pain and cognitive pain management, as well as pain-related mental impairment. All patients improved significantly in resting and relaxation techniques. With regard to pain-related helplessness and depression, patients with mental comorbidity benefitted most. Patients undergoing invasive procedures in the form of peripheral nerve blockage showed no significantly improved outcome with regard to the tested parameters. DISCUSSION: The current study demonstrated that IMPT has a highly beneficial effect on the level, experience and processing of pain in patients with CRPS.

Behavioral and neurophysiological evidence for altered interoceptive bodily processing in chronic pain.

Whereas impaired multisensory processing of bodily stimuli and distorted body representation are well-established in various chronic pain disorders, such research has focused on exteroceptive bodily cues and neglected bodily signals from the inside of the body (or interoceptive signals). Extending existing basic and clinical research, we investigated for the first time interoception and its neurophysiological correlates in patients with complex regional pain syndrome (CRPS). In three different experiments, including a total of 36 patients with CRPS and 42 aged-gender matched healthy controls, we measured interoceptive sensitivity (heart beat counting task, HBC) and neural responses to heartbeats (heartbeat evoked potentials, HEPs). As hypothesized, we observed reduced sensitivity in perceiving interoceptive bodily stimuli, i.e. their heartbeat, in two independent samples of CRPS patients (studies 1 and 2). Moreover, the cortical processing of their heartbeat, i.e. the HEP, was reduced compared to controls (study 3) and reduced interoceptive sensitivity and HEPs were related to CRPS patients' motor impairment and pain duration. By providing consistent evidence for impaired processing of interoceptive bodily cues in CRPS, this study shows that the perceptual changes occurring in chronic pain include signals originating from the visceral organs, suggesting changes in the neural body representation, that includes next to exteroceptive, also interoceptive bodily signals. By showing that impaired interoceptive processing is associated with clinical symptoms, our findings also encourage the use of interoceptive-related information in future rehabilitation for chronic pain.

Complex syndromes of chronic pain, fatigue and cognitive impairment linked to autoimmune dysautonomia and small fiber neuropathy.

Chronic fatigue syndrome, postural orthostatic tachycardia syndrome, complex regional pain syndrome and silicone implant incompatibility syndrome are a subject of debate among clinicians and researchers. Both the pathogenesis and treatment of these disorders require further study. In this paper we summarize the evidence regarding the role of autoimmunity in these four syndromes with respect to immunogenetics, autoimmune co-morbidities, alteration in immune cell subsets, production of autoantibodies and presentation in animal models. These syndromes could be incorporated in a new concept of autoimmune neurosensory dysautonomia with the common denominators of autoantibodies against G-protein coupled receptors and small fiber neuropathy. Sjogren's syndrome, which is a classical autoimmune disease, could serve as a disease model, illustrating the concept. Development of this concept aims to identify an apparently autoimmune subgroup of the disputable disorders, addressed in the review, which may most benefit from the immunotherapy.

Persons with Complex Regional Pain Syndrome Renegotiate Social Roles and Intimacy: A Qualitative Study.

OBJECTIVE: Persons with complex regional pain syndrome often experience allodynia, where touch is painful. Allodynia is associated with poor prognosis, but the impacts on roles, activities, social relationships, and intimacy remain unclear. There is a need to examine intimacy in complex regional pain syndrome from a lived experience perspective. METHODS: We conducted a secondary analysis of cognitive debriefing interview data from 44 persons with complex regional pain syndrome who completed a patient-reported questionnaire. Using interpretive description and thematic analysis, we analyzed items and responses addressing allodynia, relationships, and intimacy. RESULTS: Two themes were developed to understand intimacy related to the pain experience: a renegotiated social identity and participation and a reinvented intimate self. These themes included elements of a) loss of control, b) loss of shared experiences, c) feeling that their condition was misunderstood, d) a need for self-preservation, e) altered self-concept, and e) the concept of intimacy is broader than sexuality. Our findings suggest that complex regional pain syndrome has pervasive impacts on relationships and intimacy that merit discussion with their health care team. CONCLUSIONS: Persons with persistent pain need to be supported in roles and activities that allow them to express intimacy in their everyday lives.

Clinical Course and Impact of Complex Regional Pain Syndrome Confined to the Knee.

OBJECTIVE: Although complex regional pain syndrome (CRPS) of the knee is comparable to CRPS of the ankle/foot at time of diagnosis, no reports are available concerning the course of knee CRPS. Therefore, this study investigated the clinical course in terms of the symptoms and signs, health-related quality of life (HR-QoL), and work status of patients diagnosed with CRPS of the knee. DESIGN: Observational, descriptive study. SETTING: Single-center study. SUBJECTS: Patients with CRPS of the knee. METHODS: Patients self-reported their past and current CRPS symptoms, HR-QoL, and work status; all underwent a physical examination. A comparison was made of changes in symptoms over time between patients with CRPS of the knee and those with CRPS of more distal locations. RESULTS: In total, 32 patients were enrolled. The follow-up time was 11.5 ± 6.29 years since diagnosis, and symptoms and signs showed a significant decrease over time. Twelve patients (37.5%) rated their health as (generally) positive. Patients who were still able to work (31.3%) stated that their physical health gave them at least some problems in the performance of their job. A change in symptoms occurred significantly less often in CRPS of the knee. CONCLUSIONS: CRPS of the knee changes in terms of symptoms over time, but significantly less than CRPS of other locations. A change in work status was reported in 82% of the patients due to their CRPS, and in 91%, the pain interfered with their daily life. CRPS of the knee is a painful condition with persistent symptoms causing a diminished HR-QoL.

Prognostic Value of Pain Sensitization During Early Recovery After Distal Radius Fracture in Complex Regional Pain Syndrome.

OBJECTIVE: To evaluate the influence of pain sensitization in the early recovery of distal radius fractures (DRFs) on the occurrence and prognosis of complex regional pain syndrome (CRPS) type I. METHODS: We enrolled 58 patients who were diagnosed with CRPS I based on Budapest criteria within six months after sustaining DRF; they were age- and gender-matched with 58 patients with DRF who did not have CRPS I. We commonly measured patients' pressure pain thresholds (PPTs) in the forearm and administered a Pain Sensitivity Questionnaire (PSQ) when patients complained of pain with numeric rating scale ≥4 at three-month follow-up. Participants were followed up three, six, and 12 months after injury, and the symptoms and sign of CRPS were evaluated at each follow-up. RESULTS: Patients with CRPS I were more likely to have sustained high-energy injuries, had severe fractures, and had significantly higher PSQ scores and lower PPTs than the age- and gender-matched controls. At 12 months after injury, CRPS symptoms improved in 52% (30/58) of patients who had been diagnosed with CRPS I at three months after injury. The initial degree of pain sensitization and high-energy injury were associated with persistence of CRPS symptoms up to 12 months after initial injury. CONCLUSIONS: Patients with CRPS I after DRF exhibited significantly higher pain sensitization in the early post-trauma period, and the degree of initial pain sensitization and high-energy injuries were associated with prolonged CRPS I signs and symptoms up to one year after initial injury.

Complex Regional Pain Syndrome After Distal Radius Fracture Is Uncommon and Is Often Associated With Fibromyalgia.

BACKGROUND: Complex regional pain syndrome (CRPS) is frequently diagnosed in patients recovering from surgery or injury. The symptoms and signs included in consensus diagnostic criteria for CRPS are expected after injury. Categorizing symptoms and signs that occur on a continuum as disproportionate or not is subjective and prone to bias. Psychiatrists and psychologists do not diagnose CRPS and instead measure and treat anxiety and catastrophic thinking on its continuum. Given the expected variation in subjective diagnoses such as CRPS, this study addresses factors associated with use of this diagnosis and how it influences care. QUESTIONS/PURPOSES: (1) Among patients recovering from fracture of the distal radius, what factors are associated with the diagnosis of CRPS? (2) Are patients diagnosed with CRPS after distal radius fractures, as opposed to those without CRPS, more likely to have a bone scan, stellate ganglion block, therapy, or subsequent surgery? METHODS: Using the Truven database, we identified 59,765 patients treated for a distal radius fracture from 2012 to 2014, of whom 114 (0.19%) were diagnosed with CRPS. The Truven Health MarketScan database is an administrative claims data set of commercially insured patients and this analysis only included patients with complete enrollment from 2012 through 2014. Bivariate analyses sought differences between patients diagnosed with and patients not diagnosed with CRPS. All factors with p < 0.05 were included in a multivariable logistic regression model. RESULTS: The covariates older age (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.011-1.048; p = 0.002), gender (women at greater risk, OR, 3.86; CI, 1.99-7.49; p < 0.001), concomitant fracture of the distal ulna (OR, 1.54; CI, 1.05-2.23; p = 0.029), open fracture (OR, 0.414; CI, 0.192-0.895; p = 0.025), and comorbid fibromyalgia (OR, 16.0; CI, 4.92-51.8; p < 0.001) were independently associated with a diagnosis of CRPS among patients recovering from a fracture of the distal radius. Patients diagnosed with CRPS are more likely than other patients with a distal radius fracture to have had a bone scan (OR, 66.0; CI, 8.19-532; p < 0.001), physical or occupational therapy (OR, 3.89; CI, 2.68-5.67; p < 0.001), and subsequent wrist surgery (OR, 2.52; CI, 1.65-3.84; p < 0.001). No one had a stellate ganglion injection. CONCLUSIONS: We found that a coded diagnosis of CPRS is uncommonly applied to patients on the higher range of pain, stiffness, and limitations after fracture of the distal radius-most commonly in women and in association with another nonspecific, objectively unverifiable diagnosis (fibromyalgia)-and that this label may lead to more testing and invasive treatment. Future research should address the utility and value of diagnoses that create subjective categories for aspects of human illness that occur on a continuum. LEVEL OF EVIDENCE: Level III, prognostic study.

Association of Neglect-Like Symptoms with Anxiety, Somatization, and Depersonalization in Complex Regional Pain Syndrome.

Background: Many patients with complex regional pain syndrome (CRPS) report some foreignness of the affected limb, which is referred to as "neglect-like symptoms" (NLS). Despite similarities of the NLS reports to symptoms of body image disturbances in mental disorders, no study has been conducted to examine such associations. Methods: We investigated 50 patients with CRPS and 45 pain control patients (N = 27, chronic limb pain; N = 18, migraine headache). NLS, anxiety, depression, depersonalization, and somatization were assessed using validated questionnaires. Results: Seventy-two percent of the CRPS patients reported at least one NLS vs 29.6% and 33.3% in the two patient control groups. In limb pain controls, NLS correlated with pain intensity. In CRPS patients, NLS correlated with anxiety (rho = 0.658, P < 0.001), somatization (rho = 0.616, P < 0.001), depersonalization (rho = 0.634, P < 0.001), and pain catastrophizing (rho = 0.456, P < 0.01), but not with intensity of pain, duration of pain, or pain disability. Conclusions: In CRPS patients, NLS could be a result of somatization, depression, anxiety, and depersonalization, but probably not of pain. Whether these associations are causative must be clarified in longitudinal psychological studies.

[Cognitive-perceptive approaches in the treatment of chronic pain]. / Kognitiv-perzeptive Ansätze bei chronischen Schmerzen.

In the treatment of difficult chronic pain conditions, cognitive-perceptive approaches offer an alternative to conventional therapies. Especially phantom limb pain and complex regional pain syndrome (CRPS) are frequently treated with these promising modalities. This article provides an overview of the most important cognitive-perceptive therapies and the research results concerning their clinical efficacy. In addition, we discuss their neurobiological foundation and clinical perspectives.

Complex Regional Pain Type 1.

Complex regional pain syndrome is increasingly recognized in the pediatric population. Owing to the nature of presentation with pain, many of these children present to the emergency setting at different stages of the syndrome with or without numerous prior interactions with health professionals. Complex regional pain syndrome type 1 (CRPS1) is a clinical syndrome characterized by amplified musculoskeletal limb pain that is out of proportion to the history and physical findings, or pain due to non-noxious stimuli (allodynia/hyperalgesia), and accompanied by one or more signs of autonomic dysfunction. Differential diagnosis may include significant trauma (eg, fractures), inflammatory conditions, malignancies, and systemic illness. The diagnosis is clinical. The treatment goals for CRPS1 are restoration of function and relief of pain. Education, physical, and occupational therapy with psychotherapy and defined goals of achievement with reward are the mainstay of treatment for this population. Most children with CRPS1 will have a favorable outcome.

[Chronic pain : Perception, reward and neural processing]. / Chronischer Schmerz : Wahrnehmung, Belohnung und neurale Verarbeitung.

Many chronic pain syndromes are characterized by enhanced perception of painful stimuli as well as alterations in cortical processing in sensory and motor regions. In this review article the alterations in muscle pain and neuropathic pain are described. Alterations in patients with fibromyalgia and chronic back pain are described as examples for musculoskeletal pain and also in patients with phantom limb pain after amputation and complex regional pain syndrome as examples for neuropathic pain. In addition to altered pain perception, cumulative evidence on alterations in the processing of reward and the underlying mechanisms in chronic pain has been described. A description is given of what is known on how pain and reward interact and affect each other. The relevance of such interactions for chronic pain is discussed. The implications of these findings for therapeutic approaches are delineated with respect to sensorimotor training and behavioral therapy, focusing on the effectiveness of these approaches, mechanisms and future developments. In particular, we discuss operant behavioral therapy in patients with chronic back pain and fibromyalgia as well as prosthesis training in patients with phantom limb pain and discrimination, mirror and imaginary training in patients with phantom limb pain and complex regional pain syndrome. With respect to the processing of reward, the focus of the discussion is on the role of reward and associated learning in pain therapy.

[Pain syndrome of the musculoskeletal system in children and adolescents]. / Schmerzsyndrome des Bewegungsapparates bei Kindern und Jugendlichen.

Chronic pain syndromes in children and adolescents are defined as continuous or recurrent pain without an underlying causative diagnosis and lasting for more than 3 months. It is estimated that every fourth child in Germany suffers from chronic pain with every twentieth suffering from extreme recurrent pain. The incidence of chronic pain in children and adolescents is increasing with headache, abdominal pain and musculoskeletal pain being the most frequent. The quality of life declines not only due to the pain but to relieving postural and psychological factors, such as fear and sadness. School attendance, social activities and hobbies are mostly affected. This review summarizes the background of chronic pain syndromes and introduces a multimodal therapeutic approach.

An update on complex regional pain syndromes in children and adolescents.

PURPOSE OF REVIEW: Complex regional pain syndrome (CRPS) is a chronic pain condition typically involving a limb, which is characterized by neuropathic pain, sensory abnormalities and neurovascular findings. The exact cause of CRPS is unknown; however, proposed theories include alterations in the sympathetic and central nervous system (CNS), small fibre changes in the peripheral nervous system and psychological factors. Although this condition was previously considered rare among children and adolescents, it has been increasingly recognized in paediatric patients and can result in significant disability. RECENT FINDINGS: The diagnosis of paediatric CRPS is based upon clinical criteria obtained from a thorough history and physical examination. Other possible causes, such as orthopaedic, infectious, vascular and rheumatologic disorders, should be ruled out prior to making the diagnosis. Treatment focuses on a rehabilitative strategy consisting of physical therapy, occupational therapy and cognitive-behavioural therapy with an overall focus on return to functioning. SUMMARY: CRPS in children and adolescents is characterized by a painful, mottled appearing, swollen limb with allodynia and hyperalgesia. For most patients, pain is severe, resulting in significant functional disability. More recent evidence suggests that a rehabilitative programme results in improvement in both pain and functional measures.

The therapeutic approach to complex regional pain syndrome: light and shade.

Complex regional pain syndrome (CRPS) is a highly painful, limb-confined condition that usually arises after a trauma although its causes remain unknown. It is associated with a particularly poor quality of life, and considerable healthcare and societal costs. Its distinct combination of abnormalities includes limb-confined inflammation and tissue hypoxia, sympathetic dysregulation, small fibre damage, serum autoantibodies, central sensitisation and cortical reorganisation, which place it at the crossroads of disciplines including rheumatology, pain medicine and neurology. The significant scientific and clinical advances made over the past 10 years promise an improved understanding of the causes of CRPS, and for more effective treatments. This review summarises the currently available treatments. The therapeutic approach is multidisciplinary, and involves educating patients about the condition, sustaining or restoring limb function, reducing pain, and providing psychological support. This paper describes the systemic drug treatments, grouped on the basis of their real or presumed antinociceptive mechanisms and reported actions without making any formal distinction between CRPS types I and II.

Tactile localization training for pain, sensory disturbance, and distorted body image: a case study of complex regional pain syndrome.

This report presents a case of complex regional pain syndrome. The patient presented with severe pain, sensory disturbance, and distorted body image at the site of initial injury and other body sites. Tactile localization training (TLT) at only the site of initial injury decreased severe pain at the site of initial injury and the secondary affected sites, whereas TLT at secondary affected sites had no effect. These results highlighted the importance of assessing changes in patients' pain processes to determine the part of the body where TLT should be applied.

Short-Term Functional, Emotional, and Pain Outcomes of Patients with Complex Regional Pain Syndrome Treated in a Comprehensive Interdisciplinary Pain Management Program.

BACKGROUND: Complex regional pain syndrome (CRPS) is difficult to effectively treat with unimodal approaches. OBJECTIVE: To investigate whether CRPS can be effectively treated in a comprehensive interdisciplinary pain management program. DESIGN: Observational cohort study of 49 patients aged 18-89 who fulfilled 'Budapest Criteria' for CRPS and completed an interdisciplinary pain management program. Preprogram to postprogram changes in physical functioning, perceived disability, emotional functioning, acceptance, coping, and pain were assessed. The measures used included: Pain Disability Index, Six minute walk test, 2-minute sit-to-stand, Numerical Rating Scale, Center for Epidemiologic Studies Depression Scale, Pain Anxiety Symptoms Scale, Chronic Pain Acceptance Questionnaire, Coping Strategies Questionnaire-Revised, RIC- Multidimensional Patient Global Impression of Change (RIC-MPGIC), and Medication Quantification Scale. For worker's compensation patients, the rate of successful release to work at the end of the program was calculated. RESULTS: Results indicated significant improvements in physical functioning and perceived disability (P's<0.001). Patients reported increased usage of an adaptive coping strategy, distraction (P = 0.010), and decreased usage of maladaptive and passive strategies (P's < 0.001). Patients showed greater chronic pain acceptance (P's ≤ 0.010) and reductions in emotional distress (P's < 0.001). Medication usage at 1-month follow-up was significantly reduced compared to program start (P < 0.001) and discharge (P = 0.004). Patients reported "much improvement" in overall functioning, physical functioning, mood, and their ability to cope with pain and flare-ups (RIC-MPGIC). Patient report of pain was not significantly reduced at discharge (P =0.078). Fourteen (88%) of 16 total worker's compensation patients were successfully released to work at the end of the program. CONCLUSIONS: This study demonstrates short-term improvements in physical and emotional functioning, pain coping, and medication usage. These findings are consistent with the rehabilitation philosophy of improving functioning and sense of well-being as of equal value and relevance to pain reduction.

External Noninvasive Peripheral Nerve Stimulation Treatment of Neuropathic Pain: A Prospective Audit.

BACKGROUND: Peripheral nerve stimulation (PNS) is a neuromodulation technique in which electrical current is applied to the peripheral nerves to ameliorate chronic pain through preferential activation of myelinated fibres, inducing long-term depression of synaptic efficacy. External noninvasive peripheral nerve stimulation (EN-PNS) is a novel and simple form of PNS that involves stimulation via an external nerve-mapping probe that is placed on the skin and connected to a power source. OBJECTIVES: We aimed to assess the clinical utility of EN-PNS in patients with refractory neuropathic pains referred to a tertiary pain treatment center. METHODS: We undertook a prospective audit of EN-PNS. Patients with a diagnosis of either complex regional pain syndrome or neuropathic pain after peripheral nerve injury who met inclusion criteria were included. Participants completed three stages of the audit: stage 1, six weekly outpatient treatment sessions; stage 2, six-week equipment home loan; stage 3, six weeks of no EN-PNS treatment. The primary outcome was the average post-treatment instantaneous pain intensity during the last week in stage 2 compared with baseline (11-point numerical rating scale). RESULTS: EN-PNS provided significant short-term pain relief (n = 20 patients, average reduction of 2.8 numerical rating scale points, 95% CI 1.6-4.0, p < 0.001, intention-to-treat analysis). Eight patients (40%) improved in several outcome parameters ("responders"), including quality of life and function. CONCLUSION: In this first prospective report on the use of EN-PNS in neuropathic pain, this technology provided significant clinical benefit for some patients. Controlled studies are required to confirm our results and the place of EN-PNS in future neuromodulation treatment algorithms. Given the refractory nature of these conditions, these results are encouraging.

EFFECTS OF MEMANTINE ON PAIN IN PATIENTS WITH COMPLEX REGIONAL PAIN SYNDROME--A RETROSPECTIVE STUDY.

INTRODUCTION: Memantine was discovered in 1968 and is used as a treatment for Alzheimer's disease. We evaluated the use of memantine to treat complex regional pain syndrome in this retrospective study. PATIENTS AND METHODS: 56 patients with CRPS, who were treated with trial of memantine for at least two months with 40mg QHS from 2007 until 2009. RESULTS: 34 females and 22 male patients. Age-46.0 +/- 9.7 years. Number of years with CRPS-9.24 ± 5.7 years. Mean age-46.0 +/- 9.7 years. Memantine was started at 5 or 10 mg QHS, before being increased by 5 or 10mg every 4-7 days, as tolerated, to a maximumdose of 40 mg - 60 mg, as tolerated. In all, 13 patients showed complete remission from CRPS with VAS 0 and the disappearance of allodynea for at least nine months after the use of memantine. In addition, 18 patients showed partial improvement of VAS and allodynea. Eight patients showed no improvement even after continuous use of memantine at a dose of 40 mg QHS for two months. Seven patients could not take more than 5 mg of memantine per day and had to stop it due to side effects. In terms of subjective improvement in short-term memory, nine patients showed much improvement, 14 patients showed some improvement, three patients showed no changes and one patient did not answer the questionnaire. Regarding subjective feelings of a having better quality of life, 17 patient answered yes, three did not feel any changes, six could not give an answer and two did not fill out the questionnaire. CONCLUSIONS: Memantine is a promising option for the treatment of CRPS. A randomised controlled study is needed to evaluate its efficacy.