Katsueki Watanabe

Effective control of methicillin-resistant Staphylococcus aureus in a burn unit.

Methicillin-resistant Staph, aureus (MRSA) colonization and infection was studied in 231 patients who were admitted to our burn unit and remained for 3 days or more between 1986 and 1994 (patients with inhalation injury only and no burn wound were excluded). The study was divided into two periods: from 1988 to 1989 and from 1990 to 1994. MRSA was found in 80 patients. They increased from 1986 to 1988, slightly decreasing thereafter. In 1994 the incidence of MRSA was 4.3 per cent. The number of strains of MRSA isolated from burn wounds was significantly reduced in the later period. Comparing the two periods, isolation of patients from MRSA, prevention of contamination during care, and reduction in the number of patients initially given second- or third-generation cephem antibiotics were performed more strictly in the later period. The effectiveness of these measures was confirmed. Moreover, the first operation was carried out significantly earlier in the later period. Early excision and early closure of the wound was more effective in preventing and controlling MRSA colonization and infection.

Haemodynamic Changes in Early Phase Reflex Sympathetic Dystrophy

We studied six patients with early phase reflex sympathetic dystrophy (RSD). Osteoporotic changes were noted in the bones of the affected limb. Despite higher temperatures indicated by thermography, laser speckle image sensing showed no increase in blood flow on the skin surface. Digital subtraction angiography showed arteriovenous shunting or increased density of perfused vessels. Based on these results, we speculate that in RSD persistent vascular contraction caused by pain leads to the formation of arteriovenous shunts in the affected limb with an ischaemic state in the peripheral subcutaneous tissue which is indicated by pain and swelling.

Comparison of Doppler sonography and multidetector-row computed tomography in the imaging findings of the deep inferior epigastric perforator artery.

Background:Multidetector-row computed tomography (MDCT) has been recently introduced to detect the perforator vessels. The aim of this study is to compare the MDCT with Doppler ultrasound and assess the usefulness of the MDCT for the preoperative planning. Methods:Five healthy adult men were first assessed for the perforators and marked with rubber using the Doppler ultrasound before MDCT was performed. Using these images, the number and the location of the perforator were evaluated. Results:We could detect 83 perforators on five cases, while could detect 35 perforators by the Doppler ultrasound. We measured the distance from the fascia perforating points to rubber markings points. It ranged from 0 to 22.47 mm (7.62 mm on average). Conclusion:MDCT angiography is useful for preoperative planning of deep inferior epigastric artery perforator flap at the point of more accurate anatomical findings and clear images of perforator vessels compared to the findings using Doppler ultrasound.

A burn wound healing model in the hairless descendant of the Mexican hairless dog

Wound contraction and epithelialization occur much faster in animals than in humans. Therefore it is sometimes not valid to apply the results of animal wound healing studies to humans. Hairless descendants of Mexican hairless dogs (HD-MHD) have attracted attention because their skin characteristics approximate those of humans. We used this animal and compared the rate of healing of superficial dermal burns (SDB) and deep dermal burns (DDB) in the HD-MHD and normal beagles. We also compared the rate of healing with use of Vaseline (Chesebrough-Ponds) gauze (VG) and hydrocolloid dressings in the HD-MHD. The HD-MHD demonstrated less contraction (p < 0.05). Small pigmented spots could be seen in the HD-MHD wounds, suggesting that epithelialization started from epidermal appendages. SDBs treated with VG and hydrocolloid dressings were both epithelialized on day 18. DDBs treated with hydrocolloid dressings were epithelialized on day 24, whereas DDBs treated with VG were epithelialized on day 30. Like human wounds, burns in the HD-MHD epithelialize from appendages with less wound contraction. These similarities support the use of this burn wound healing model.

Chronological histological findings of cultured epidermal autograft over bilayer artificial dermis.

The application of cultured epidermal autograft (CEA) over bilayer artificial dermis theoretically should minimize surgical stress and donor site morbidity in severe burn patients. However, CEA over regenerated dermis is very fragile and easily detaches soon after application, because the very weak attachment. We performed chronological histological studies of the wounds of a 29 year-old patient, which was reconstructed using CEA (JACE(®)) and bilayer artificial dermis (Integra™). These studies included immunohistochemistry of anti-collagen (types III, IV, and VII) and anti-laminin, in addition to H&E and EVG staining. Reconstructed epidermis and dermis showed almost normal histological appearance with time, but formation of basement membrane proteins was delayed. Absent or immature basement membrane protein in the early phase after the CEA application was considered to be an important problem. In the late phase after the CEA application over the bilayer artificial dermis, the reconstructed skin was very durable and demonstrated no sign of skin stripping (although there was still a lack of basement membrane proteins).

The estimation of tissue loss during tangential hydrosurgical debridement.

Abstract The preservation of healthy tissue during surgical debridement is desirable as this may improve clinical outcomes. This study has estimated for the first time the amount of tissue lost during debridement using the VERSAJET system of tangential hydrosurgery. A multicenter, prospective case series was carried out on 47 patients with mixed wound types: 21 (45%) burns, 13 (28%) chronic wounds, and 13 (28%) acute wounds. Overall, 44 (94%) of 47 patients achieved appropriate debridement after a single debridement procedure as verified by an independent photographic assessment. The percentage of necrotic tissue reduced from a median of 50% to 0% (P < 0.001). Median wound area and depth increased by only 0.3 cm2 (6.8%) and 0.5 mm (25%), respectively. Notably, 43 (91%) of 47 wounds did not progress into a deeper compartment, indicating a high degree of tissue preservation.

High-tension electrical injury to the heart as assessed by radionuclide imaging

To evaluate cardiac complications associated with electrical injury, 7 patients with high-tension electrical injury (6,600 V alternating current) underwent201Tl and123I-metaiodobenzylguanidine (MIBG) imaging in addition to conventional electrocardiographic and echocardiographic assessments. Electrocardiography showed transient atrial fibrillation, second degree atrioventricular block, ST-segment depression, and sinus bradycardia in each patient. Echocardiography showed mild hypokinesis of the anterior wall in only 2 patients, but201Tl and123I-MIBG myocardial scintigraphy whowed an abnormal scan image in 6/7 and 5/6 patients, respectively. Decreased radionuclide accumulation was seen primarily in areas extending from the anterior wall to the septum. Decreased radionuclide accumulation was smaller in extent and milder in degree in123I-MIBG than in201Tl imaging. These results suggest that even in patients without definite evidence of severe cardiac complications in conventional examinations, radionuclide imaging detects significant damage due to high-tension electrical injury, in which sympathetic nerve dysfunction might be milder than myocardial cell damage.

Reconstruction of the sole and heel and infancy in childhood followed up for more than 10 years.

We evaluated 10 patients in which the initial reconstruction of the weight-bearing area of the sole and heel was performed in infancy or childhood and which had been followed up more than 10 years. In the initial operations, a cross-leg flap was used in 5, full-thickness skin graft in 5, and split-thickness skin graft in 1 (in 1 patient, both a cross-leg flap and a full-thickness skin flap was used). Secondary reconstruction was performed using skin graft from non-weight-bearing areas in 6 patients and a cross-leg flap in 1 patient. In infancy and childhood, temporary closure of a wound by skin graft from the inguinal area or a cross-leg flap was attempted. Initial reconstruction using the non-weight-bearing area must be performed carefully in infancy and childhood.

Cranial defect and decrease in cerebral blood flow resulting from deep contact burn of the scalp in the neonatal period.

A case of cranial defect in the anterior fontanelle region is reported. The patient suffered a deep contact burn on the right parietofrontal region in the neonatal period. At age 3 years, a bone defect of 30 x 20 mm was observed in the right parietofrontal region, including the anterior fontanelle, and the pulsation of the brain was palpable. Moreover, scintigraphy of cerebral blood flow using SPECT with 99mTc-HMPAO demonstrated extensive decrease in blood flow in the right parietosquamosal region. Cranioplasty was performed at 3 years and 4 months using split ribs grafts and at age 5 years and 4 months using split-thickness calvarial bone grafts. After the cranioplasty, there was no bony defect and no region of reduced blood flow. The child is developing well.

The role of carbon monoxide poisoning in the production of inhalation burns

Because heat and many poisonous chemicals are generated in a fire, studies of inhalation burns have tended to focus on injury by heat and irritative chemicals. In view of the frequent carbon monoxide (CO) poisoning associated with bum deaths and in patients with inhalation burns, however, nonirritative poisonous gases such as CO cannot be disregarded as possible causative factors involved in the production of inhalation burns. Accordingly, we attempted to clarify in animals the effect of nonlethal CO poisoning on inhalation burns due to heated air. The experimental results indicate that inhaling an amount of moderately heated dry air that alone could not cause pulmonary injury produces severe pulmonary injury in the presence of CO. This seems to occur because CO poisoning causes hyperventilation and thus allows a massive amount of heat to reach the lung.