Acupuncture treatment of phantom limb pain and phantom limb sensation in amputees.
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Three case histories are presented in which amputees with acute or chronic phantom limb pain and phantom limb sensation were treated with Western medical acupuncture, needling the asymptomatic intact limb. Two out of the three cases reported complete relief of their phantom limb pain and phantom limb sensation. Acupuncture was successful in treating phantom phenomena in two of these cases, but a larger cohort study would be needed to provide more evidence for the success rate of this treatment technique for this indication. (+info)
Comparative study between patellar-tendon-bearing and pressure cast prosthetic sockets.
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This study compared the pressure distribution at the residual limb and socket interface in amputees wearing a pressure cast (PCast) socket system with amputees wearing the patellar-tendon-bearing (PTB) socket. The PCast system requires the subject to place his or her residual limb in a pressure chamber. Pressure is applied to the residual limb while the subject adopts a normal standing position. Four unilateral male amputees were fitted with both PTB and PCast sockets. Using a specially built strain-gauge-type pressure transducer, we recorded residual limb and socket pressure profiles for each subject wearing the two types of sockets during standing and walking. While some subjects exhibited similar anterior-posterior or medial-lateral pressure profiles for both prostheses, especially during push-off, other subjects exhibited high pressure distally in the PCast socket or higher-pressure concentration at the proximal region in the PTB socket. (+info)
Shape and volume change in the transtibial residuum over the short term: preliminary investigation of six subjects.
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A preliminary investigation was conducted to characterize the magnitude and distribution of volume change in transtibial residua at two time intervals: upon prosthesis removal and at 2 week intervals. Six adult male unilateral transtibial amputee subjects, between 0.75 and 40.0 years since amputation, were imaged 10 times over a 35-minute interval with a custom residual limb optical scanner. Volume changes and shape changes over time were assessed. Measurements were repeated 2 weeks later. Volume increase on socket removal for the six subjects ranged from 2.4% to 10.9% (median 6.0% +/- standard deviation 3.6%). Rate of volume increase was highest immediately upon socket removal and decreased with time (five subjects). In four subjects, 95% of the volume increase was reached within 8 minutes. No consistent proximal-to-distal differences were detected in limb cross-sectional area change over time. Limb volume differences 2 weeks apart ranged from -2.0% to 12.6% (0.6% +/- 5.5%) and were less in magnitude than those within a session over the 35-minute interval (five subjects). Multiple mechanisms of fluid movement may be responsible for short-term volume changes, with different relative magnitudes and rates in different amputees. (+info)
Dissociation of phantom limb phenomena from stump tactile spatial acuity and sensory thresholds.
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Most amputees experience phantom limb sensations and/or phantom limb pain as well as residual limb (stump) pain that are resistant to treatment. Phantom phenomena are not homogeneous; each patient presents with a unique combination of spontaneous or evoked sensations, pain, and/or awareness. In an effort to understand the underlying mechanisms, postamputation pain has been subclassified based on the perceived sensory qualities reported by the individual. However, little is known about the relationship between subjective phantom phenomena and sensory function of the residual stump. The aim of the present study was to determine if sensory processing, as measured psychophysically, reflected subjective reports of specific qualities of phantom and/or stump sensory phenomena. Twelve individuals who had recently (within 6 months) undergone traumatic unilateral upper extremity amputation participated in the study. Limb temperature, thermal thresholds, tactile sensory thresholds and tactile spatial acuity were compared between the residual limb and the intact limb, and related to patient reports of specific stump and phantom sensory phenomena. All but one subject reported phantom sensations and/or phantom pain. The remaining subject reported only stump pain. Mean skin temperature of the residual limb was significantly lower than that of the intact contralateral limb by approximately 0.9 degrees C in the proximal portion of the stump and 1.7 degrees C at the stump tip. However, the temperature of the stump (compared with the intact limb) did not reflect subjective reports of stump or phantom limb thermal characteristics. Thermal threshold abnormalities differed among patients, and did not suggest any pattern of small fibre loss of function or generalized hyperexcitability. Other than within grafted tissue or near the scar area, skin areas that the patient described as abnormally sensitive or tender to touch were not accompanied by corresponding abnormalities in static tactile thresholds or tactile spatial acuity. Tactile spatial acuity was heightened near the scar area only. The proportion of subjects who had decreased two-point discrimination thresholds at the stump did not differ significantly according to the reporting or non-reporting of dual percepts. Thus, despite a common injury, the sensory abnormalities varied within this cohort of subjects. In addition, psychophysical threshold measures of sensory function did not reflect, in any simple way, subjective phantom phenomena. Therefore, classification of phantom phenomena based on peripheral sensory function may be a misleading step in the search for specific mechanisms underlying postamputation sensory phenomena. (+info)
Reducing contralateral SI activity reveals hindlimb receptive fields in the SI forelimb-stump representation of neonatally amputated rats.
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In adult rats that sustained forelimb amputation on the day of birth, >30% of multiunit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) also respond to cutaneous hindlimb stimulation when cortical GABA(A+B) receptors are blocked (GRB). This study examined whether hindlimb receptive fields could also be revealed in forelimb-stump sites by reducing one known source of excitatory input to SI GABAergic neurons, the contralateral SI cortex. Corpus callosum projection neurons connect homotopic SI regions, making excitatory contacts onto pyramidal cells and interneurons. Thus in addition to providing monosynaptic excitation in SI, callosal fibers can produce disynaptic inhibition through excitatory synapses with inhibitory interneurons. Based on the latter of these connections, we hypothesized that inactivating the contralateral (intact) SI forelimb region would "unmask" normally suppressed hindlimb responses by reducing the activity of SI GABAergic neurons. The SI forelimb-stump representation was first mapped under normal conditions and then during GRB to identify stump/hindlimb responsive sites. After GRB had dissipated, the contralateral (intact) SI forelimb region was mapped and reversibly inactivated with injections of 4% lidocaine, and selected forelimb-stump sites were retested. Contralateral SI inactivation revealed hindlimb responses in approximately 60% of sites that were stump/hindlimb responsive during GRB. These findings indicate that activity in the contralateral SI contributes to the suppression of reorganized hindlimb receptive fields in neonatally amputated rats. (+info)
Histomorphometric changes in the vessel wall at the site of amputation in diabetic patients--do they influence healing of the stump?
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PURPOSE: To predict healing of the stump by assessing the microscopic vascular changes at the amputation site. METHODS: A cohort study was conducted on 39 patients, 18 of them had below-knee amputation (group A) and 21 had ray amputation of a single toe (group B). Biopsies were taken from the anterior and posterior tibial arteries and the venae comitantes of group A patients. For group B patients, biopsies of the digital artery and dorsal vein of the toe were taken. RESULTS: In group A, 15 patients required no further amputation (group A1) and 3 underwent a further above-knee amputation (group A2). In group B, 16 required no further amputation (group B1) and 5 underwent a below-knee amputation (group B2). Lumen narrowing caused by intimal thickening of the arteries was significantly different between groups A1 and A2 (p<0.05). Lumen narrowing of the dorsal veins between groups B1 and B2 was also significantly different (p<0.05). The proportion of the vessel walls made up of intima and media was significantly different in both A1 and A2 as well as B1 and B2 groups. The proportion of total wall thickness over the total diameter of the vessel was not significantly different between both subgroups of A and B. CONCLUSION: Intimal thickening and medial thinning in the arteries can be used to predict the stump healing in patients who underwent below-knee amputation. For ray amputation patients, similar changes occurred in the dorsal veins, and this finding can also be used to predict the healing of the stump. However, intimal thickening occurred at the expense of the media; therefore, there is little change in the wall thickness. (+info)
A preliminary investigation into the development of 3-D printing of prosthetic sockets.
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The socket is considered an element of major importance in the makeup of a prosthesis. Each socket is a tailor-made device, designed to fit the unique geometry of the patient's residual limb. The design and manufacture of a prosthetic socket traditionally has been a manual process that relies on the use of plaster of Paris casts to capture the shape of the patient's residual limb and then artisan fabrication techniques to manufacture the socket. Computer-aided design and manufacturing technologies have overcome some of the shortcomings of the traditional process, but the final manufacture of the prosthetic socket is still performed manually. Rapid prototyping (RP), a relatively new class of manufacturing technologies, creates physical models directly from three-dimensional (3-D) computer data. Previous research into the application of RP systems to the manufacture of prosthetic sockets has focused on expensive, high-end technologies that have proven too expensive. This paper investigates the use of a cheaper, low-end RP technology known as 3-D printing. Our investigation was an initial approach to using a technology that is normally associated with producing prototypes quickly, some of which could not be manufactured by alternative means. Under normal circumstances, these printed components are weak and relatively fragile. However, comfortable prosthetic sockets manufactured with 3-D printing have been used in preliminary fittings with patients. (+info)
Residual-limb skin temperature in transtibial sockets.
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The insulated environment of the lower-limb prosthesis can result in elevated residual-limb skin temperatures that may contribute to skin irritation, blistering, and a reduced quality of life. The design and materials of the prosthetic socket, suspension system, and liner can potentially alleviate these conditions, but the thermal load may vary with activity and location within the socket. To characterize the thermal environment at the skin-prosthesis interface, we made temperature measurements on five transtibial amputees at 14 locations on the residual limbs. After the participants donned their prosthesis and rested in the seated position for 15 min, the mean skin temperatures of their residual limbs increased by 0.8 degrees Celcius. Subsequent walking for 10 min resulted in a 1.7 degrees Celsius total increase in mean skin temperature. Thermal contour maps revealed the skin was coolest at the anterior proximal location and warmest across the posterior section, correlating with areas of low and high perfusion. From the results, we determined that residual-limb skin temperature depends on activity and locality. This information may aid in understanding where and why skin problems develop on lower-limb residual limbs and may provide design requirements for new prosthetic socket systems intended to alleviate temperature-related discomfort. (+info)