RESUMEN
An evaluation of wound mechanics is crucial in reflecting the wound healing status. The present study examined the biomechanical properties of healing rat skin wounds in vivo and ex vivo. Thirty male Sprague-Dawley rats, each with a 6 mm full-thickness circular punch biopsied wound at both posterior hind limbs were used. The mechanical stiffness at both the central and margins of the wound was measured repeatedly in five rats over the same wound sites to monitor the longitudinal changes over time of before wounding, and on days 0, 3, 7, 10, 14, and 21 after wounding in vivo by using an optical coherence tomography-based air-jet indentation system. Five rats were euthanized at each time point, and the biomechanical properties of the wound tissues were assessed ex vivo using a tensiometer. At the central wound bed region, the stiffness measured by the air-jet system increased significantly from day 0 (17.2%), peaked at day 7 (208.3%), and then decreased progressively until day 21 (40.2%) as compared with baseline prewounding status. The biomechanical parameters of the skin wound samples measured by the tensiometer showed a marked reduction upon wounding, then increased with time (all p < 0.05). On day 21, the ultimate tensile strength of the skin wound tissue approached 50% of the normal skin; while the stiffness of tissue recovered at a faster rate, reaching 97% of its prewounded state. Our results suggested that it took less time for healing wound tissues to recover their stiffness than their maximal strength in rat skin. The stiffness of wound tissues measured by air-jet could be an indicator for monitoring wound healing and contraction.
Asunto(s)
Ensayo de Materiales/métodos , Fenómenos Mecánicos , Piel/lesiones , Cicatrización de Heridas , Animales , Fenómenos Biomecánicos , Masculino , Ratas , Ratas Sprague-Dawley , Piel/citología , Resistencia a la TracciónRESUMEN
BACKGROUND: Skin blood flow plays an important role in maintaining the health of the skin. The development of interstitial edema may impede oxygen diffusion to the skin. The aim of this study was to evaluate the association of skin blood flow and edema and epidermal thickness in the feet of people with and without diabetic neuropathy compared with a healthy control group. SUBJECTS AND METHODS: Eighty-seven subjects (19 people with diabetic neuropathy and foot ulceration, 35 people with diabetes but without neuropathy, and 33 healthy controls without diabetes) participated in the study. High-frequency ultrasonography was used to measure the epidermal thickness and edema in papillary skin at the big toe as reflected by the thickness of the subepidermal low echogenic band (SLEB). The capillary nutritive blood flow was measured by the use of video capillaroscopy, and skin blood flux was monitored by laser Doppler flowmetry. RESULTS: There was a 7.2% increase in epidermal thickness in those with diabetes but without neuropathy and a 16.5% decrease in people with diabetic neuropathy and foot ulceration compared with the healthy controls (all P<0.05). The SLEB thickness increased in all subjects with diabetes to a greater degree in those with neuropathy and ulceration than in those without (64.7% vs. 11.8%, P<0.001). Skin blood flux was shown to be higher in the diabetes groups than in the controls (all P<0.05), but no significant differences were found in the resting nutritive capillary blood flow (P>0.05). A significant negative correlation (P=0.002, r=-0.366) was demonstrated between the SLEB and epidermal thickness at the pulp of the big toe, whereas no significant correlation was demonstrated between skin blood flow and epidermal thickness (all P>0.05). CONCLUSIONS: An increase in subepidermal edema was demonstrated in people with diabetic neuropathy and ulceration, which may partly contribute to reduced epidermal thickness at the pulp of the big toe. This may subsequently lead to the breaking down of skin in the diabetic foot.
Asunto(s)
Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 1/fisiopatología , Pie Diabético/patología , Pie Diabético/fisiopatología , Edema/fisiopatología , Hallux , Piel/patología , Anciano , Velocidad del Flujo Sanguíneo , Presión Sanguínea , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/complicaciones , Pie Diabético/etiología , Femenino , Hemoglobina Glucada/metabolismo , Hallux/irrigación sanguínea , Hallux/patología , Humanos , Flujometría por Láser-Doppler , Masculino , Microcirculación , Piel/irrigación sanguíneaRESUMEN
Diabetic foot is a common complication for people with diabetes but it is unclear whether the change is initiated from the skin surface or underneath plantar tissues. This study compared the thickness of epidermis and the thickness and stiffness of the total plantar soft tissue among people with diabetes with or without complications. Seventy-two people with diabetes, including 22 people with neuropathies, 16 foot ulcerations, 34 pure diabetics without complications and 40 healthy controls participated in the study. The thickness of the epidermal layer of the plantar skin was examined using high-frequency ultrasonography; the thickness and stiffness of the total plantar soft tissue were measured by using tissue ultrasound palpation system at the big toe, the first, third and fifth metatarsal heads; and the heel pad. Compared with the control group, the average epidermal thickness of plantar skin was reduced by 15% in people with diabetic foot ulceration and 9% in people with neuropathy, but was increased by 6% in pure diabetics. There was an 8% increase in total thickness of plantar soft tissue in the 3 diabetic groups at all testing sites (all p < 0.05), except the first metatarsal head. The stiffness of plantar soft tissue was increased in all diabetic groups at all testing sites compared with the control (all p < 0.05). The epidermal plantar skin becomes thinner and plantar soft tissues stiffen in people with diabetes, particularly in persons who have neuropathy or ulceration, which increases the risk of tissue breakdown and ulceration formation.
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Pie Diabético/diagnóstico por imagen , Pie Diabético/patología , Anciano , Análisis de Varianza , Fenómenos Biomecánicos , Estudios de Casos y Controles , Pie Diabético/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procesamiento de Señales Asistido por Computador , Programas Informáticos , Ultrasonografía , Interfaz Usuario-ComputadorRESUMEN
A novel noncontact optical coherence tomography based air-jet indentation system was developed for characterizing the biomechanical properties of soft tissue in a noncontact way. This study aimed to measure the stiffness of diabetic foot ulcer tissues by using this air-jet indentation system, and examining the test/retest reliability. Eight subjects with diabetes (seven males, one female), with a total of 10 foot ulcers between them, participated in the study. A total of 20 measuring sites located at the central wound bed (n=10) or peri-ulcer areas (n=10), respectively, were evaluated with the air-jet indentation system. Four cycles of loading and unloading, each with a duration of approximately 36 seconds at an indentation rate of 0.08 mm/s, were carried out for each indentation trial. The test/retest reliability was examined at all measuring points. The average stiffness coefficient of the peri-ulcer area (mean ± SD: 0.47 ± 0.15 N/mm) was significantly larger than that of the central wound bed area (mean ± SD: 0.35 ± 0.23 N/mm; p=0.042). A high value for test/retest reliability was shown (intraclass correlation coefficient: 0.986; Pearson's correlation: r=0.972, p<0.001). Our preliminary findings showed that the peri-ulcer area had greater stiffness than the central wound bed. This greater magnitude of hardness and inelasticity at the peri-ulcer region may scatter part of the contractile forces for wound contraction during the healing process. We found the novel air-jet system to be a reliable tool for characterizing the stiffness of soft tissues around the wound in a noncontact way.
Asunto(s)
Pie Diabético/fisiopatología , Tomografía de Coherencia Óptica/métodos , Cicatrización de Heridas/fisiología , Anciano , Aire , Fenómenos Biomecánicos , Elasticidad , Diseño de Equipo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: The forefoot medial plantar area withstand high plantar pressure during locomotion, and is a common site that develops foot lesion problems among elderly people. The aims of the present study were to (1) determine the correlation between the biomechanical properties of forefoot medial plantar soft tissue measured by a newly developed optical coherence tomography-based air-jet indentation system and by tissue ultrasound palpation system, and (2) to compare the biomechanical properties of plantar soft tissues of medial forefoot between a young and old adult group. METHODS: Thirty healthy subjects were classified as the young or older group. The biomechanical properties of plantar soft tissues measured at the forefoot by the air-jet indentation system and tissue ultrasound palpation system were performed, and the correlation of the findings obtained in the two systems were compared. FINDINGS: A strong positive correlation was obtained from the findings in the two systems (r=0.88, P<0.001). The forefoot plantar soft tissue of the older group was significantly stiffer at the second metatarsal head and thinner at both metatarsal heads than that of the young group (all P<0.05). The stiffness coefficient at the second metatarsal head was 28% greater than that at the first metatarsal head in both study groups. INTERPRETATION: Older subjects showed a loss of elasticity and reduced thickness in their forefoot plantar soft tissue, with the second metatarsal head displaying stiffer and thicker plantar tissue than the first metatarsal head. The air-jet indentation system is a useful instrument for characterizing the biomechanical properties of soft tissue.
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Antepié Humano/fisiología , Tomografía de Coherencia Óptica/métodos , Adulto , Factores de Edad , Anciano , Aire , Fenómenos Biomecánicos , Diseño de Equipo , Femenino , Antepié Humano/anatomía & histología , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/patología , UltrasonidoRESUMEN
Diabetic foot disease and ulceration is a major complication that may lead to the amputation of the lower limbs. Microangiopathy may play a significant role in the pathogenesis of tissue breakdown in the diabetic foot. However, the precise mechanisms of this process remain unclear and poorly understood. Microvasculature in the skin is comprised of nutritive capillaries and thermoregulatory arteriovenous shunt flow. It is regulated through the complex interaction of neurogenic and neurovascular control. The interplay among endothelial dysfunction, impaired nerve axon reflex activities, and microvascular regulation in the diabetic patient results in the poor healing of wounds. Skin microvasculature undergoes both morphologic changes as well as functional deficits when parts of the body come under stress or injury. Two important theories that have been put forward to explain the abnormalities that have been observed are the haemodynamic hypothesis and capillary steal syndrome. With advances in medical technology, microvasculature can now be measured quantitatively. This article reviews the development of microvascular dysfunction in the diabetic foot and discusses how it may relate to the pathogenesis of diabetic foot problems and ulceration. Common methods for measuring skin microcirculation are also discussed.
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Pie Diabético/patología , Pie Diabético/fisiopatología , Fibras Adrenérgicas/fisiología , Humanos , Microcirculación , Microvasos/patología , Microvasos/fisiopatología , Piel/irrigación sanguínea , Piel/inervaciónRESUMEN
OBJECTIVE: To examine whether the addition of either electroacupuncture or interferential electrotherapy to shoulder exercises would be more effective in the management of frozen shoulder. DESIGN: A double-blinded, randomized, controlled trial. METHODS: A total of 70 subjects were randomly allocated to receive either: (i) electroacupuncture plus exercise; (ii) interferential electrotherapy plus exercise; or (iii) no treatment (the control group). Subjects in groups (i) and (ii) received 10 sessions of the respective treatment, while the control group received no treatment for 4 weeks. Each subject's score on the Constant Murley Assessment and visual analogue scale were recorded at baseline, post-treatment session and subsequent follow-up sessions. RESULTS: In both the electroacupuncture and interferential electrotherapy groups, the Constant Murley Assessment score increased and the visual analogue scale score decreased significantly (both p < 0.001). No significant change was found in any outcome of the control group, and no significant difference was found between the 2 intervention groups (all p > 0.05). The observed improvement was well maintained in both intervention groups at least until the 6-month follow-up session. CONCLUSION: Either electroacupuncture or interferential electrotherapy in combination with shoulder exercises is effective in treating frozen shoulder patients. However, no significant difference was found between these types of treatment.