Rapid treatment-induced brain changes in pediatric CRPS

Complex regional pain syndrome: a narrative review for the practising clinician

Complex regional pain syndrome (CRPS) is a life-altering condition that usually affects the extremities after a trauma or nerve injury. The physiologic changes that occur as a result of the inciting injury are complex, as the name of the syndrome implies. The pain and disability associated with CRPS often lead to psychological co-morbidities that create a vicious cycle of pain, isolation, and depression. We review recent developments in the understanding of CRPS and advancements in management of this syndrome. Further research in targeting specific mechanisms involved in the pathophysiology of CRPS should lead to prevention of this condition.

Catastrophizing, pain, and functional outcomes for children with chronic pain: a meta-analytic review

Pediatric chronic pain is associated with numerous negative outcomes including increased physical disability, increased rates of depression and anxiety, and decreased quality of life (QOL). Pain catastrophizing-broadly conceptualized as including rumination, magnification, and helplessness cognitions surrounding one's pain-has been linked with poor functional outcomes in children with chronic pain. Pain catastrophizing in pediatric chronic pain is often considered a key factor on which to focus treatment efforts. However, absent a systematic review that integrates the relevant literature, this call for routine assessment and targeted treatment may be premature. This study aimed to: (1) meta-analytically quantify the relationship between catastrophizing and pain and functional/psychosocial outcomes (functional disability/physical functioning, anxiety, depression, and QOL) in children with chronic pain, and (2) examine potential moderators of these relationships. Using a random-effects model, a total of 111 effect sizes from 38 studies were analyzed. Effect sizes ranged from medium to large, with anxiety, depression, and QOL demonstrating a strong association with catastrophizing. Pain intensity and physical disability had a moderate association with catastrophizing. These relationships were robust, minimizing potential publication bias. None of the examined moderators were significant. The strong relationships found between catastrophizing and anxiety, depression, and QOL suggest that successfully intervening on catastrophizing could have far reaching implications in improving pain outcomes in pediatric chronic pain.

Neurobiological mechanisms underlying the sleep-pain relationship in adolescence: A review

Adolescence characterizes a period of significant change in brain structure and function, causing the neural circuitry to be particularly susceptible to the environment and various other experiences. Chronic pain and sleep deprivation represent major health issues that plague adolescence. A bidirectional relationship exists between sleep and pain; however, emerging evidence suggests that sleep disturbances have a stronger influence on subsequent pain than vice versa. The neurobiological underpinnings of this relationship, particularly during adolescence, are poorly understood. This review examines the current literature regarding sleep and pain in adolescence, with a particular focus on the neurobiological mechanisms underlying pain, sleep problems, and the neural circuitry that potentially links the two. Finally, a research agenda is outlined to stimulate future research on this topic. Given the high prevalence of these health issues during adolescence and the debilitating effects they inflict on nearly every domain of development, it is crucial that we determine the neurobiological mechanisms fundamental to this relationship and identify potential therapeutic strategies.

When pain gets stuck: the evolution of pain chronification and treatment resistance

It is well-recognized that, despite similar pain characteristics, some people with chronic pain recover, whereas others do not. In this review, we discuss possible contributions and interactions of biological, social, and psychological perturbations that underlie the evolution of treatment-resistant chronic pain. Behavior and brain are intimately implicated in the production and maintenance of perception. Our understandings of potential mechanisms that produce or exacerbate persistent pain remain relatively unclear. We provide an overview of these interactions and how differences in relative contribution of dimensions such as stress, age, genetics, environment, and immune responsivity may produce different risk profiles for disease development, pain severity, and chronicity. We propose the concept of "stickiness" as a soubriquet for capturing the multiple influences on the persistence of pain and pain behavior, and their stubborn resistance to therapeutic intervention. We then focus on the neurobiology of reward and aversion to address how alterations in synaptic complexity, neural networks, and systems (eg, opioidergic and dopaminergic) may contribute to pain stickiness. Finally, we propose an integration of the neurobiological with what is known about environmental and social demands on pain behavior and explore treatment approaches based on the nature of the individual's vulnerability to or protection from allostatic load.

Recovery from acute pediatric complex regional pain syndrome type I after ankle sprain by early pharmacological and physical therapies in primary care: a case report

Background

Complex regional pain syndrome type I (CRPS I) in children is a serious condition disrupting the family and school life of patients with the condition after it fully develops. It has been emphasized that early diagnosis is closely associated with earlier reduction of pain leading to preferable outcomes.

Objectives

To report a case of acute CRPS I in a boy who was found to develop this condition by a routine visual analog scale (VAS) pain monitoring and who recovered from CRPS I at an early phase by prompt pharmacological, physical, and educational therapies.

Study design

Case report.

Case report

A 12-year-old boy sprained his left ankle while playing soccer and was referred to our clinic 4 days after the injury. At the first visit, he could walk, reporting motion pain with a VAS scale of 80 mm. On day 5, pain intensity increased to 100 mm, and a diagnosis of acute CRPS I was made. On day 7, he could not move the injured ankle; therefore celecoxib and pregabalin were administered, and physical and educational therapies started. On day 35, pain intensity was 0 mm and he could walk and run normally.

Conclusion

Routine monitoring of VAS for every patient in pain is useful to discover an abnormal transition of VAS, enabling the early diagnosis of CRPS I. Inflammation and peripheral or central sensitization are postulated for early development of CRPS I. The present case suggested a combination of physical therapy and pharmacological intervention with celecoxib and pregabalin reduced peripheral and central sensitization.

Prolonged, widespread, disabling musculoskeletal pain of adolescents among referrals to the Pediatric Rheumatology Outpatient Clinic from the Päijät-Häme Hospital District in southern Finland

Background and aims Musculoskeletal pain among adolescents is a problem for the patients and their families and has economic consequences for society. The aim of this study is to determine the incidence of prolonged disabling musculoskeletal pain of adolescents among referrals to a pediatric rheumatology outpatient clinic and describe the patient material. The second aim is to find proper screening tools which identifies patients with a risk of pain chronification and to test whether our patients fit the Pediatric Pain Screening Tool (PPST) stratification according to Simons et al. Methods We selected adolescent patients with disabling, prolonged, musculoskeletal pain and calculated the incidence. Furthermore, after the patient collection, we adjusted our pain patients to PPST. Results The incidence of prolonged musculoskeletal pain patients at our clinic was 42/100,000 patient years (pyrs) (age 13-18; 95% CI: 29-60) during years 2010-2015. A nine-item screening tool by Simons et al. proves to be valid for our patient group and helps to identify those patients who need early, prompt treatment. The functional risk stratification by Simons et al. correlates with our patients' functional disability. Conclusions and implications In order to prevent disability and to target intervention, it is necessary to have proper and rapid screening tools to find the appropriate patients in time.

Role of the Prefrontal Cortex in Pain Processing

The prefrontal cortex (PFC) is not only important in executive functions, but also pain processing. The latter is dependent on its connections to other areas of the cerebral neocortex, hippocampus, periaqueductal gray (PAG), thalamus, amygdala, and basal nuclei. Changes in neurotransmitters, gene expression, glial cells, and neuroinflammation occur in the PFC during acute and chronic pain, that result in alterations to its structure, activity, and connectivity. The medial PFC (mPFC) could serve dual, opposing roles in pain: (1) it mediates antinociceptive effects, due to its connections with other cortical areas, and as the main source of cortical afferents to the PAG for modulation of pain. This is a ‘loop’ where, on one side, a sensory stimulus is transformed into a perceptual signal through high brain processing activity, and perceptual activity is then utilized to control the flow of afferent sensory stimuli at their entrance (dorsal horn) to the CNS. (2) It could induce pain chronification via its corticostriatal projection, possibly depending on the level of dopamine receptor activation (or lack of) in the ventral tegmental area-nucleus accumbens reward pathway. The PFC is involved in biopsychosocial pain management. This includes repetitive transcranial magnetic stimulation, transcranial direct current stimulation, antidepressants, acupuncture, cognitive behavioral therapy, mindfulness, music, exercise, partner support, empathy, meditation, and prayer. Studies demonstrate the role of the PFC during placebo analgesia, and in establishing links between pain and depression, anxiety, and loss of cognition. In particular, losses in PFC grey matter are often reversible after successful treatment of chronic pain.

Anterior insular volume decrease is associated with dysfunction of the reward system in patients with chronic pain

BACKGROUND

Chronification of pain is associated with both anatomical and functional alterations of the brain. Alteration in regional grey matter volume might potentially be associated with modified activity of specific brain networks. In this cross-sectional, observational study, we sought to identify brain regions with grey matter volume changes in patients with chronic pain and to reveal its significance by analysing alteration in functional connectivity from those regions. We further explored relevance of such alterations with psychometrics of chronic pain.

METHODS

We recruited 23 patients with chronic pain and 17 age-, gender-matched healthy control subjects. After completing multiple psychophysical questionnaires, each subject underwent resting-state functional magnetic resonance imaging and three-dimensional anatomical imaging on a 3 Tesla magnetic resonance imaging scanner.

RESULTS

Patients with chronic pain showed significant volume decrease at the right anterior insular cortex (p < 0.001) and the left middle cingulate cortex (p < 0.001) compared with healthy controls. They also showed decreased connectivity between the right anterior insular cortex and the left nucleus accumbens in negative association with the Pain Catastrophizing Scale (R²  = 0.20, p = 0.046) and the Beck's Depression Inventory scores (R²  = 0.24, p = 0.017).

CONCLUSIONS

Decreased grey matter volumes of those core regions for affective processing of pain might be a common cerebral feature shared by, at least some of, different aetiologies of chronic pain. Dysfunctional network between the anterior insular cortex and the nucleus accumbens might reflect affective and motivational disability involved in chronic pain. Such anatomical and functional profiles could potentially be part of a cerebral signature for chronification of pain.

SIGNIFICANCE

This article illustrates decreased network activity of the reward system in association with insular cortical volume decrease in patients with chronic pain, and its close relationships with affective and cognitive morbidity of pain. Attenuation of brain's reward system involving cortical plastic changes might have a key role in chronification of pain.

A critical evaluation of validity and utility of translational imaging in pain and analgesia: Utilizing functional imaging to enhance the process

Assessing clinical pain and metrics related to function or quality of life predominantly relies on patient reported subjective measures. These outcome measures are generally not applicable to the preclinical setting where early signs pointing to analgesic value of a therapy are sought, thus introducing difficulties in animal to human translation in pain research. Evaluating brain function in patients and respective animal model(s) has the potential to characterize mechanisms associated with pain or pain-related phenotypes and thereby provide a means of laboratory to clinic translation. This review summarizes the progress made towards understanding of brain function in clinical and preclinical pain states elucidated using an imaging approach as well as the current level of validity of translational pain imaging. We hypothesize that neuroimaging can describe the central representation of pain or pain phenotypes and yields a basis for the development and selection of clinically relevant animal assays. This approach may increase the probability of finding meaningful new analgesics that can help satisfy the significant unmet medical needs of patients.

How do morphological alterations caused by chronic pain distribute across the brain? A meta-analytic co-alteration study

•In chronic pain, gray matter (GM) alterations are not distributed randomly across the brain.•The pattern of co-alterations resembles that of brain connectivity.•The alterations' distribution partly rely on the pathways of functional connectivity.•This method allows us to identify tendencies in the distribution of GM co-alteration related to chronic pain.

The Dorsolateral Prefrontal Cortex in Acute and Chronic Pain

The dorsolateral prefrontal cortex (DLPFC) is a functionally and structurally heterogeneous region and a key node of several brain networks, implicated in cognitive, affective, and sensory processing. As such, the DLPFC is commonly activated in experimental pain studies, and shows abnormally increased function in chronic pain populations. Furthermore, several studies have shown that some chronic pains are associated with decreased left DLPFC gray matter and that successful interventions can reverse this structural abnormality. In addition, studies have indicated that noninvasive stimulation of the left DLPFC effectively treats some chronic pains. In this article, we review the neuroimaging literature regarding the role of the DLPFC and its potential as a therapeutic target for chronic pain conditions, including studies showing the involvement of the DLPFC in encoding and modulating acute pain and studies demonstrating the reversal of DLPFC functional and structural abnormalities after successful interventions for chronic pain. We also review studies of noninvasive brain stimulation of the DLPFC showing acute pain modulation and some effectiveness as a treatment for certain chronic pain conditions. We further discuss the network architecture of the DLPFC, and postulate mechanisms by which DLPFC stimulation alleviates chronic pain. Future work testing these mechanisms will allow for more effective therapies.

PERSPECTIVE

The structure and function of the DLPFC is abnormal in some chronic pain conditions. Upon successful resolution of pain, these abnormalities are reversed. Understanding the underlying mechanisms and the role of this region can lead to the development of an effective therapeutic target for some chronic pain conditions.

Impaired insula functional connectivity associated with persistent pain perception in patients with complex regional pain syndrome

Given that the insula plays a contributory role in the perception of chronic pain, we examined the resting-state functional connectivity between the insular cortex and other brain regions to investigate neural underpinnings of persisting perception of background pain in patients with complex regional pain syndrome (CRPS). A total of 25 patients with CRPS and 25 matched healthy controls underwent functional magnetic resonance imaging at rest. With the anterior and posterior insular cortices as seed regions, we compared the strength of the resting-state functional connectivity between the two groups. Functional connectivity between the anterior and posterior insular cortices and the postcentral and inferior frontal gyri, cingulate cortices was reduced in patients with CRPS compared with controls. Additionally, greater reductions in functional connectivity between the anterior insula and right postcentral gyrus were associated with more severe sensory pain in patients with CRPS (short-form McGill Pain Questionnaire sensory subscores, r = -.517, P = .023). The present results imply a possible role of the insula in aberrant processing of pain information in patients with CRPS. The findings suggest that a functional derangement of the connection between one of the somatosensory cortical functions of perception and one of the insular functions of awareness can play a significant role in the persistent experience of regional pain that is not confined to a specific nerve territory.

The Potential Role of Sensory Testing, Skin Biopsy, and Functional Brain Imaging as Biomarkers in Chronic Pain Clinical Trials: IMMPACT Considerations

Valid and reliable biomarkers can play an important role in clinical trials as indicators of biological or pathogenic processes or as a signal of treatment response. Currently, there are no biomarkers for pain qualified by the U.S. Food and Drug Administration or the European Medicines Agency for use in clinical trials. This article summarizes an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials meeting in which 3 potential biomarkers were discussed for use in the development of analgesic treatments: 1) sensory testing, 2) skin punch biopsy, and 3) brain imaging. The empirical evidence supporting the use of these tests is described within the context of the 4 categories of biomarkers: 1) diagnostic, 2) prognostic, 3) predictive, and 4) pharmacodynamic. Although sensory testing, skin punch biopsy, and brain imaging are promising tools for pain in clinical trials, additional evidence is needed to further support and standardize these tests for use as biomarkers in pain clinical trials.

PERSPECTIVE

The applicability of sensory testing, skin biopsy, and brain imaging as diagnostic, prognostic, predictive, and pharmacodynamic biomarkers for use in analgesic treatment trials is considered. Evidence in support of their use and outlining problems is presented, as well as a call for further standardization and demonstrations of validity and reliability.

Modern pain neuroscience in clinical practice: applied to post-cancer, paediatric and sports-related pain

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Generalized hypersensitivity in post-cancer, sports-related and pediatric pain.

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Rationale for pain education, stress management and cognition targeted exercises.

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Need to change from a biomedical or psychosocial to an integrated approach.

In the last decade, evidence regarding chronic pain has developed exponentially. Numerous studies show that many chronic pain populations show specific neuroplastic changes in the peripheral and central nervous system. These changes are reflected in clinical manifestations, like a generalized hypersensitivity of the somatosensory system. Besides a hypersensitivity of bottom-up nociceptive transmission, there is also evidence for top-down facilitation of pain due to malfunctioning of the endogenous descending nociceptive modulatory systems. These and other aspects of modern pain neuroscience are starting to be applied within daily clinical practice. However, currently the application of this knowledge is mostly limited to the general adult population with musculoskeletal problems, while evidence is getting stronger that also in other chronic pain populations these neuroplastic processes may contribute to the occurrence and persistence of the pain problem. Therefore, this masterclass article aims at giving an overview of the current modern pain neuroscience knowledge and its potential application in post-cancer, paediatric and sports-related pain problems.

Neuroplasticity of Supraspinal Structures Associated with Pathological Pain

Peripheral nerve and spinal cord injuries, along with other painful syndromes such as fibromyalgia, diabetic neuropathy, chemotherapeutic neuropathy, trigeminal neuralgia, complex regional pain syndrome, and/or irritable bowel syndrome, cause several neuroplasticity changes in the nervous system along its entire axis affecting the different neuronal nuclei. This paper reviews these changes, focusing on the supraspinal structures that are involved in the modulation and processing of pain, including the periaqueductal gray matter, red nucleus, locus coeruleus, rostral ventromedial medulla, thalamus, hypothalamus, basal ganglia, cerebellum, habenula, primary, and secondary somatosensory cortex, motor cortex, mammillary bodies, hippocampus, septum, amygdala, cingulated, and prefrontal cortex. Hyperexcitability caused by the modification of postsynaptic receptor expression, central sensitization, and potentiation of presynaptic delivery of neurotransmitters, as well as the reduction of inhibitory inputs, changes in dendritic spine, neural circuit remodeling, alteration of gray matter, and upregulation of proinflammatory mediators (e.g., cytokines) by reactivation of astrocytes and microglial cells are the main functional, structural, and molecular neuroplasticity changes observed in the above supraspinal structures, associated with pathological pain. Studying these changes in greater depth may lead to the implementation and improvement of new therapeutic strategies against pathological pain. Anat Rec, 300:1481-1501, 2017. © 2017 Wiley Periodicals, Inc.

The Insula: A "Hub of Activity" in Migraine

The insula, a "cortical hub" buried within the lateral sulcus, is involved in a number of processes including goal-directed cognition, conscious awareness, autonomic regulation, interoception, and somatosensation. While some of these processes are well known in the clinical presentation of migraine (i.e., autonomic and somatosensory alterations), other more complex behaviors in migraine, such as conscious awareness and error detection, are less well described. Since the insula processes and relays afferent inputs from brain areas involved in these functions to areas involved in higher cortical function such as frontal, temporal, and parietal regions, it may be implicated as a brain region that translates the signals of altered internal milieu in migraine, along with other chronic pain conditions, through the insula into complex behaviors. Here we review how the insula function and structure is altered in migraine. As a brain region of a number of brain functions, it may serve as a model to study new potential clinical perspectives for migraine treatment.

Why Harmless Sensations Might Hurt in Individuals with Chronic Pain: About Heightened Prediction and Perception of Pain in the Mind

In individuals with chronic pain harmless bodily sensations can elicit anticipatory fear of pain resulting in maladaptive responses such as taking pain medication. Here, we aim to broaden the perspective taking into account recent evidence that suggests that interoceptive perception is largely a construction of beliefs, which are based on past experience and that are kept in check by the actual state of the body. Taking a Bayesian perspective, we propose that individuals with chronic pain display a heightened prediction of pain [prior probability p(pain)], which results in heightened pain perception [posterior probability p(pain|sensation)] due to an assumed link between pain and a harmless bodily sensation [p(sensation|pain)]. This pain perception emerges because their mind infers pain as the most likely cause for the sensation. When confronted with a mismatch between predicted pain and a (harmless bodily) sensation, individuals with chronic pain try to minimize the mismatch most likely by active inference of pain or alternatively by an attentional shift away from the sensation. The active inference results in activities that produce a stronger sensation that will match with the prediction, allowing subsequent perceptual inference of pain. Here, we depict heightened pain perception in individuals with chronic pain by reformulating and extending the assumptions of the interoceptive predictive coding model from a Bayesian perspective. The review concludes with a research agenda and clinical considerations.

Post-traumatic stress symptoms in children and adolescents with chronic pain: A topical review of the literature and a proposed framework for future research

BACKGROUND AND OBJECTIVE

The co-occurrence of chronic pain and post-traumatic stress symptoms (PTSS) and post-traumatic stress disorder (PTSD) has gained increasing research attention. Studies on associations among pain and PTSS or PTSD in youth have largely been conducted in the context of acute injury or trauma. Less is known about the risk for co-occurrence with paediatric chronic pain. In this review, we (1) propose a conceptual framework to outline factors salient during childhood that may be associated with symptom severity, co-occurrence and mutual maintenance, (2) present relevant literature on PTSS in youth with acute and chronic pain and identify research gaps and (3) provide recommendations to guide paediatric research examining shared symptomatology.

DATABASES AND DATA TREATMENT

Electronic databases (PubMed and Google Scholar) were used to identify relevant articles using the search terms 'child, adolescent, paediatric, chronic pain, acute pain, post-traumatic stress symptoms and post-traumatic stress disorder'. Studies were retrieved and reviewed based on relevance to the topic.

RESULTS

Our findings revealed that existing biobehavioural and ecological models of paediatric chronic pain lack attention to traumatic events or the potential development of PTSS. Paediatric studies are also limited by lack of a conceptual framework for understanding the prevalence, risk and trajectories of PTSS in youth with chronic pain.

CONCLUSIONS

Our new developmentally informed framework highlights individual symptoms and shared contextual factors that are important when examining potential associations among paediatric chronic pain and PTSS. Future studies should consider bidirectional and mutually maintaining associations, which will be aided by prospective, longitudinal designs. WHAT DOES THIS REVIEW ADD?: This review presents relevant literature on pain and PTSS in youth and proposes a conceptual framework to examine factors salient during childhood that may be associated with symptom severity, comorbidity and mutual maintenance of chronic pain and PTSS in paediatric populations. We highlight dynamic factors that may change across children's development and provide recommendations to guide paediatric research examining potential associations among PTSS and chronic pain.

Pain in an era of armed conflicts: Prevention and treatment for warfighters and civilian casualties

Chronic pain is a common squealae of military- and terror-related injuries. While its pathophysiology has not yet been fully elucidated, it may be potentially related to premorbid neuropsychobiological status, as well as to the type of injury and to the neural alterations that it may evoke. Accordingly, optimized approaches for wounded individuals should integrate primary, secondary and tertiary prevention in the form of thorough evaluation of risk factors along with specific interventions to contravene and mitigate the ensuing chronicity. Thus, Premorbid Events phase may encompass assessments of psychological and neurobiological vulnerability factors in conjunction with fostering preparedness and resilience in both military and civilian populations at risk. Injuries per se phase calls for immediate treatment of acute pain in the field by pharmacological agents that spare and even enhance coping and adaptive capabilities. The key objective of the Post Injury Events is to prevent and/or reverse maladaptive peripheral- and central neural system's processes that mediate transformation of acute to chronic pain and to incorporate timely interventions for concomitant mental health problems including post-traumatic stress disorder and addiction We suggest that the proposed continuum of care may avert more disability and suffering than the currently employed less integrated strategies. While the requirements of the armed forces present a pressing need for this integrated continuum and a framework in which it can be most readily implemented, this approach may be also instrumental for the care of civilian casualties.

Fear and Reward Circuit Alterations in Pediatric CRPS

In chronic pain, a number of brain regions involved in emotion (e.g., amygdala, hippocampus, nucleus accumbens, insula, anterior cingulate, and prefrontal cortex) show significant functional and morphometric changes. One phenotypic manifestation of these changes is pain-related fear (PRF). PRF is associated with profoundly altered behavioral adaptations to chronic pain. For example, patients with a neuropathic pain condition known as complex regional pain syndrome (CRPS) often avoid use of and may even neglect the affected body area(s), thus maintaining and likely enhancing PRF. These changes form part of an overall maladaptation to chronic pain. To examine fear-related brain circuit alterations in humans, 20 pediatric patients with CRPS and 20 sex- and age-matched healthy controls underwent functional magnetic resonance imaging (fMRI) in response to a well-established fearful faces paradigm. Despite no significant differences on self-reported emotional valence and arousal between the two groups, CRPS patients displayed a diminished response to fearful faces in regions associated with emotional processing compared to healthy controls. Additionally, increased PRF levels were associated with decreased activity in a number of brain regions including the right amygdala, insula, putamen, and caudate. Blunted activation in patients suggests that (a) individuals with chronic pain may have deficits in cognitive-affective brain circuits that may represent an underlying vulnerability or consequence to the chronic pain state; and (b) fear of pain may contribute and/or maintain these brain alterations. Our results shed new light on altered affective circuits in patients with chronic pain and identify PRF as a potentially important treatment target.

The Plasticity of Brain Gray Matter and White Matter following Lower Limb Amputation

Accumulating evidence has indicated that amputation induces functional reorganization in the sensory and motor cortices. However, the extent of structural changes after lower limb amputation in patients without phantom pain remains uncertain. We studied 17 adult patients with right lower limb amputation and 18 healthy control subjects using T1-weighted magnetic resonance imaging and diffusion tensor imaging. Cortical thickness and fractional anisotropy (FA) of white matter (WM) were investigated. In amputees, a thinning trend was seen in the left premotor cortex (PMC). Smaller clusters were also noted in the visual-to-motor regions. In addition, the amputees also exhibited a decreased FA in the right superior corona radiata and WM regions underlying the right temporal lobe and left PMC. Fiber tractography from these WM regions showed microstructural changes in the commissural fibers connecting the bilateral premotor cortices, compatible with the hypothesis that amputation can lead to a change in interhemispheric interactions. Finally, the lower limb amputees also displayed significant FA reduction in the right inferior frontooccipital fasciculus, which is negatively correlated with the time since amputation. In conclusion, our findings indicate that the amputation of lower limb could induce changes in the cortical representation of the missing limb and the underlying WM connections.