Phantom
The Central African Republic (CAR) is if anything worse than a failed state: it has become virtually a phantom state, lacking any meaningful institutional capacity at least since the fall of Emperor Bokassa in 1979.
phantom
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Phantom limb pain is the perception of pain or discomfort in a limb that is no longer there. PLP most commonly presents as a sequela of amputation. The underlying pathophysiology remains poorly understood. The condition should be differentiated from other related clinical conditions such as residual limb pain, which was formerly called "stump pain" and is pain that originates from the actual site of the amputated limb that tends to resolve with wound healing. This activity describes the evaluation and management of phantom limb pain and highlights the role of the interprofessional team in the management of this pain.
Objectives:Describe the epidemiology of phantom limb pain.Review the presentation of a patient with phantom limb pain.Outline the treatment options for phantom limb pain.Explain the importance of improving coordination amongst interprofessional team members to optimize outcomes for patients suffering from phantom limb pain.Access free multiple choice questions on this topic.
In the United States (U.S.), 30,000 to 40,000 amputations are performed each year. Amputations can occur for many reasons including severe trauma, tumors, vascular disease, and infection. Pain after amputation of a limb is a common symptom and is separated into two types of pain including residual limb pain (RLP) and phantom limb pain (PLP). PLP is clinically defined as the perception of pain or discomfort in a limb that no longer exists. Although PLP most commonly presents as pathological sequelae in amputee patients, the underlying pathophysiology remains poorly understood. Furthermore, PLP can present along a wide clinical spectrum and varying severity of symptoms. The condition should be differentiated from other related but separate clinical conditions, including RLP. This latter condition, formerly known as "stump pain", is pain that originates from the actual site of the amputated limb. It is most common in the early post-amputation period and tends to resolve with wound healing. Unlike PLP, RLP is often a manifestation of an underlying source, such as nerve entrapment, neuroma formation, surgical trauma, ischemia, skin breakdown, or infection.[1][2] Of note, more than half of people with PLP also have RLP. It is important to know the difference between the two because the causes and treatments for each differ, but also be aware that both of these elements can coexist at the same time.[3]
PLP and RLP represent an important challenge in medicine, in terms of epidemiology and therapeutic difficulties. Ninety-five percent of patients, indeed, report experiencing some amputation-related pain, with 79.9% reporting phantom pain and 67.7% reporting RLP. Again, these clinical manifestations can significantly worsen the health-related quality of life (HR-QOL) and in some cases are very difficult to manage.
The exact etiology of PLP is unclear. Multiple theories have been debated, and the only agreement is that multiple mechanisms are likely responsible. The predominant theory for years involved the irritation of the severed nerve endings causing phantom pain. This was enforced by evidence that almost all amputation patients will develop neuromas in the residual limb. Over the last few decades, advances in imaging and laboratory techniques have shown evidence of central nervous system (CNS) involvement. Imaging studies such as MRI and PET scans show activity in the areas of the brain associated with the amputated limb when the patient feels phantom pain. The pain is now thought to involve many peripheral and central nervous system factors.[4][5]
Despite, the phantom limb sensation was described by French military surgeon Ambroise Pare (1510-1590) in the sixteenth century, even today we do not have a clear explanation of this complex phenomenon and, therefore, the pathophysiology is explained by a wide range of mechanisms. These mechanisms. which are the basis of theories, they are not necessarily mutually exclusive
In the spinal cord, a process called central sensitization occurs. Central sensitization is a process where neural activity increases, the neuronal receptive field expands, and the nerves become hypersensitive. This is due to an increase in the N-methyl-D-aspartate, or NMDA, activity in the dorsal horn of the spinal cord making them more susceptible to activation by substance P, tachykinins, and neurokinins followed by an upregulation of the receptors in that area. This restructuring of the neural components of the spinal cord can cause the descending inhibitory fibers to lose their target sites. The combination of increased activity to nociceptive signals as well as a decrease in the inhibitory activity from the supraspinal centers is thought to be one of the major contributors to phantom limb pain. [7]
Over the past few years, there has been significant research into cortical reorganization and is a commonly cited factor in phantom limb pain. During this process, the areas of the cortex that represent the amputated area are taken over by the neighboring regions in both the primary somatosensory and the motor cortex. Cortical reorganization partially explains why nociceptive stimulation of the nerves in the residual limb and surrounding area can cause pain and sensation in the missing limb. There is also a correlation between the extent of cortical reorganization and the amount of pain that the patient feels. [8]
Chronic pain has been shown to be multi-factorial with a strong psychological component. Phantom limb pain can often develop into chronic pain syndrome and for treatment to have a higher chance of success the patient's pain behaviors and pain processing should be addressed. Depression, anxiety, and increased stress are all triggers for phantom limb pain. [9]
Twelve hundred American amputees who are military veterans were surveyed by questionnaire about their amputations, pain sensitivity, demography, treatment history, stump problems, phantom sensations, and phantom pain. Over sixty percent responded and of these 85 percent reported significant amounts of phantom pain. This is in sharp contrast to both the literature and our clinical experience which indicate that although most amputees seen in a clinical setting report some occasional minor discomfort due to their phantoms, only between one half percent and five percent experience severe phantom pain. There was no relationship between reasons for amputation, use of prosthesis, pain sensitivity, age, years since amputation, or other demographic variables and presence of severity of phantom pain. Those respondents describing phantom pain usually had either momentary episodes of intense, debilitating pain, or virtually continuous discomfort varying in intensity but reaching debilitating levels occasionally. The fairly continuous pains were all similar in description to magnified versions of comfortable phantom sensations reported by other respondents. Few of the reported treatments were of any value.
Background: Phantom limb pain is a debilitating condition for which no effective treatment has been found. We hypothesised that re-engagement of central and peripheral circuitry involved in motor execution could reduce phantom limb pain via competitive plasticity and reversal of cortical reorganisation.
Methods: Patients with upper limb amputation and known chronic intractable phantom limb pain were recruited at three clinics in Sweden and one in Slovenia. Patients received 12 sessions of phantom motor execution using machine learning, augmented and virtual reality, and serious gaming. Changes in intensity, frequency, duration, quality, and intrusion of phantom limb pain were assessed by the use of the numeric rating scale, the pain rating index, the weighted pain distribution scale, and a study-specific frequency scale before each session and at follow-up interviews 1, 3, and 6 months after the last session. Changes in medication and prostheses were also monitored. Results are reported using descriptive statistics and analysed by non-parametric tests. The trial is registered at ClinicalTrials.gov, number NCT02281539.
Interpretation: Our findings suggest potential value in motor execution of the phantom limb as a treatment for phantom limb pain. Promotion of phantom motor execution aided by machine learning, augmented and virtual reality, and gaming is a non-invasive, non-pharmacological, and engaging treatment with no identified side-effects at present.
P = phantom(def,n) generates an image of a head phantom that can be used to test the numerical accuracy of radon and iradon or other two-dimensional reconstruction algorithms. P is a grayscale image that consists of one large ellipse (representing the brain) containing several smaller ellipses (representing features in the brain). def specifies the type of head phantom to generate, and n specifies the number of rows and columns in the phantom image.
P = phantom(E,n) generates a user-defined phantom, where each row of the matrix E specifies an ellipse in the image. E has six columns, with each column containing a different parameter for the ellipses.
Three-dimensional computerized representations of the human body, referred to as computational phantoms, have been used in the fields of medical physics and radiation protection for decades to study people exposed to medical, occupational, and environmental radiation. PHANTOM is a library of state-of-the-art, whole-body computational phantoms representing children and adults of different body heights and weights. Each phantom contains more than 100 carefully delineated organs or tissues. 041b061a72