• Archives of Plastic Surgery
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• v.37 no.5
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• pp.547-554
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• 2010

Purpose: The purpose of this study is to delineate the optimal time of venous revascularization for preventing the flap necrosis due to venous occlusion, and to clarify the usefulness of tissue oxygen pressure ($TcpO_2$) in the determination of the point of time for venous revascularization. Methods: Thirty-six, $3{\times}3\;cm$ sized epigastric island flap was elevated in left abdomen of male Sprague-Dawley rat weighing 250 gram. Flaps were randomly assigned to six groups of six flaps according to the duration of venous occlusion with microvascular clamp; 10 minutes in the group I as the control, 60 minutes in the group II, 2 hours in the group III, 3 hours in the group IV, 4 hours in the group V, and 6 hours in the group VI, respectively. Just before removal of clamp after flap was reposed in situ, the ratio of $TcpO_2$ (tissue oxygen pressure) of the island flap to that of right abdomen was calculated in each group, and tissue specimen was harvested from the distal area of the flap for histological evaluation of vascular change. Five days later, survival area of the flap was estimated, and evaluated the correlation between the tissue oxygen pressure and the rate of flap survival. Results: The $TcpO_2$ and the survival rate of flap were decreased proportionally with the duration of venous occlusion. The ratio of the $TcpO_2$ of the flap is decreased abruptly to below sixty percentile compared to the $TcpO_2$ of normal tissue, and the survived area of the flap is decreased to nine-tenth of the designed size after three hours of total venous occlusion. Histologically, the number of congested vessels was increased according to venous occluded time, and proportionally increased after 3-hours of occlusion significantly. Conclusion: There is a close correlation between the $TcpO_2$ and the survival rate of flaps according to the duration of venous occlusion. Therefore, the $TcpO_2$ represents the hemodynamic changes within the flap, and thought to be an alternative effective tool in the flap monitoring for venous revascularization.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.585-589
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• 2011

Purpose: Microcirculation of diabetic patients is commonly comporomised, regardless of the condition of the macrocirculation. Therefore, direct tissue oxygenation measurement is recommended in determining tissue viability and predicting wound healing potential. This study was designed to determine cut-off value of the tissue oxygenation in predicting wound healing in diabetic foot patients. Methods: This study included 41 feet of 41 diabetic foot patients who were treated in the Diabetic Wound Center of author's institution between January and June, 2009. Main inclusion criteria were type 1 or 2 diabetes and a foot ulcer (duration > 3 weeks) and ulcer area (from 1 $cm^2$ to 4 $cm^2$). Measurements of the area of diabetic foot ulcer were carried out before treatment. Transcutaneous oxygen pressure ($TcpO_2$) was measured at adjacent site of ulcer. The healing wound was defined as complete wound closure within 12 weeks. Results: Average diabetic foot ulcer areas with healing and nonhealing wounds were $2.67{\pm}0.76$ and $2.59{\pm}0.75\;cm^2$, respectively. There was no significant difference in the wound area between the groups. Average foot $TcpO_2$ in healing and nonhealing wounds were $68.56{\pm}23.07$ and $30.98{\pm}16.66$ mmHg, respectively ($p$ <0.01). The rate of healing wound increased as $TcpO_2$ increased. In particular, $TcpO_2$ lower than 40 mmHg and higher than 40 mmHg showed the most significant difference (wound healing rates of 25% and 71%, respectively). Conclusion: Based on the results of the study, the minimal $TcpO_2$ value thought to be required for adequate wound healing in diabetic wounds (cut-off value) is 40 mmHg.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.668-672
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• 2014

Background Negative-pressure wound therapy (NPWT) is believed to accelerate wound healing by altering wound microvascular blood flow. Although many studies using laser Doppler have found that NPWT increases perfusion, recent work using other modalities has demonstrated that perfusion is reduced. The purpose of this study was to investigate the influence of NPWT on tissue oxygenation of the foot, which is the most sensitive region of the body to ischemia. Methods Transcutaneous partial pressure of oxygen ($TcpO_2$) was used to determine perfusion beneath NPWT dressings of 10 healthy feet. The sensor was placed on the tarso-metatarsal area of the foot and the NPWT dressing was placed above the sensor. $TcpO_2$ was measured until it reached a steady plateau state. The readings obtained at the suction-on period were compared with the initial baseline (pre-suction) readings. Results $TcpO_2$ decreased significantly immediately after applying NPWT, but gradually increased over time until reaching a steady plateau state. The decrease in $TcpO_2$ from baseline to the steady state was 2.9 to 13.9 mm Hg (mean, $9.3{\pm}3.6$ mm Hg; $13.5{\pm}5.8%$; P<0.01). All feet reached a plateau within 20 to 65 minutes after suction was applied. Conclusions NPWT significantly decrease tissue oxygenation of the foot by 2.9 to 13.9 mm Hg. NPWT should be used with caution on feet that do not have adequate tissue oxygenation for wound healing.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.148-152
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• 2010

Purpose: In treating diabetic foot ulcers, satisfactory vascularity is an essential prerequisite. To improve vascularity, a bypass graft has long been carried out. Recently, however, percutaneous transluminal angioplasty (PTA) has also been tried since the PTA is less invasive than the bypass graft. However, publication demonstrating the improvement of vascularity after the PTA are lacking. Therefore, this study was designed to show usefulness of the PTA in treating vasculopathy of diabetic foot. Materials: and Methods This study included 30 feet of 24 ischemic diabetic foot patients. Inclusion criteria were diabetes (duration > 5 years) and a significant lower extremity ischemia, as determined by a transcutaneous oxygen pressure ($TcpO_2$) < 30 mmHg. The PTA was carried out in 61 arteries. PTA procedure was considered successful, when residual stenosis was less than 30%. The procedure was considered failed when residual stenosis was more than 50%. Residual stenosis between 30% and 50% was considered acceptable. For evaluation of PTA effect, foot $TcpO_2$ and infrared thermography were measured before and 7th day after PTA. Results: Immediately after PTA performed in 61 arteries, 58 and 3 arteries were evaluated as being successful and acceptable, respectively. Before PTA, average foot $TcpO_2$ was $12.6{\pm}8.8$ mmHg and its value was increased to $44.2{\pm}23.9$ on 7th day after PTA (p<0.01). Average skin temperature was $31.8{\pm}1.2^{\circ}C$ before PTA and it was increased to $33.5{\pm}1.1^{\circ}C$ on 7th day after PTA (p<0.01). Conclusion: PTA procedure increases tissue oxygenation of ischemic diabetic feet which do not have wound healing potential due to low tissue oxygenation, to the level of possible wound healing. In addition, PTA increases skin temperature of ischemic diabetic feet which can imply an improvement of peripheral circulation.