Digital Volumetric Measurements Based on 3D Scans of the Lower Limb: A Valid and Reproducible Method for Evaluation in Lymphedema Therapy.

BACKGROUND: Exact quantification of volumetric changes of the extremities is difficult and often error-prone. The aim of this study was to establish a standardized method based on 3-dimensional (3D) scans. Furthermore, this study tests the method in terms of reproducibility and evaluates volume changes after surgical therapy in patients suffering from lymphedema on the lower extremity. METHODS: 3D scans of the lower limb were performed with a mobile 3D scanner; "repeatability" and "interobserver reliability" of digital volumetry were tested. Furthermore, the method was applied on 31 patients suffering from chronic lymphedema. RESULTS: Calculations of repeatability of the volume based on 20 3D scans of the same lower leg showed a mean volume of 2.488 ± 0.011 liters (range: 2.470-2.510). The mean volume of the different examiners did not differ significantly (F(2,18) = 1.579, P = 0.233). The paired t-test showed a significant mean volume decrease of 375 mL (95% confidence interval = 245/505 mL) between pretreatment and post-treatment (t (30) = 5.892, P < 0.001). CONCLUSIONS: 3D volumetry is a noninvasive, easy, and quick method to assess volume changes of the lower leg. Other than the low costs, it is reproducible and precise and therefore ideal for evolution of therapy in lymphedema.

The influence of negative pressure wound therapy on bacterial and fungal growth.

BACKGROUND: The use of negative pressure wound therapy (NPWT) in superinfected wounds is controversial. The mechanism of action is unclear, but recent studies have shown lower atmospheric oxygen levels within the dressing. Therefore, different oxygen-favoring bacteria and fungi might benefit or face impaired thriving conditions. The aim of this in vitro study is to investigate the influence of NPWT on bacterial and fungal growth. METHODS: Salmonella enterica subsp. enterica serovar Typhimurium, Pseudomonas aeruginosa and Candida albicans strains were cultured on concentrated agars and attached to a standard NPWT-device. After 48 hours, colonies were separately harvested from the agar and foam. Optical density (OD) was obtained in order to estimate bacterial loads. RESULTS: For all tested microorganisms, no overall significant differences were found compared to controls. Subanalysis showed lower OD levels from the agar beneath the foam in the NPWT-group. CONCLUSION: NPWT removed bacteria and fungi from the wound surface but accumulation is found within the foam. The use of NPWT showed no influence on bacterial or fungal growth selection. With superinfected wounds, the use of NPWT should thoroughly be evaluated as toxins and virulence factors may not fully be evacuated.

Technical Aspects of High-Resolution Color-Coded Duplex Sonography for the Design of Perforator Flaps.

BACKGROUND: Technical aspects are of utmost significance for an efficient execution in designing perforator flaps with high-resolution color-coded Duplex sonography (CCDS). The following study evaluates decisive factors for a successful microvessel examination conducted by the microsurgeon. METHODS: Technical knowledge presented in this study was based on a series of more than 200 perforator flaps planned with CCDS. Flap reconstructions were performed at the University Hospital Regensburg, Germany, from July 2013 to January 2021. Standard high-resolution ultrasound (US) devices with linear multifrequency transducers of 4 to 18 MHz were used. Modes and device settings were evaluated regarding applicability by microsurgeons. Key steps for safe perforator identification and further optional steps for additional assessment should be discriminated. RESULTS: Different US modes including brightness mode (B-mode), color flow (CF), power Doppler (PD), pulse wave (PW), and blood flow (B-Flow) were used. Transducers from 15 MHz and up were favorable to detect microvessels. Knobology of a standard US device regarding buttons, switches, and specific onscreen options with relevance for perforator mapping was subcategorized in four different groups. For qualitative and quantitative evaluation of microvessels, different US modes were tested with respect to their usefulness.Vital elements of the CCDS exam are disaggregated into three key steps for safe perforator identification and three optional steps for further perforator characterization. A standardized protocol for the CCDS exams was applied. Downregulation of pulse-repetition frequency/scale to adapt device sensitivity to slow-flow velocities represented the most important criterion to visualize microvessels.Qualitative microvessel evaluation was performed in B-mode, CCDS, PD mode, and B-Flow mode. Quantitative assessment was executed using PW-mode and CCDS measuring the microvessels' diameter (mm) and flow characteristics. Quantitative information may be obtained using PW-mode and the distance-measuring tool in CF-mode. CONCLUSION: Technical aspects with respect to proper device trimming and application decisively impact CCDS-guided perforator vessel identification and evaluation.

Alkylated epidermal creatine kinase as a biomarker for sulfur mustard exposure: comparison to adducts of albumin and DNA in an in vivo rat study.

Sulfur mustard (SM) is a chemical warfare agent which use is banned under international law and that has been used recently in Northern Iraq and Syria by the so-called Islamic State. SM induces the alkylation of endogenous proteins like albumin and hemoglobin thus forming covalent adducts that are targeted by bioanalytical methods for the verification of systemic poisoning. We herein report a novel biomarker, namely creatine kinase (CK) B-type, suitable as a local biomarker for SM exposure on the skin. Human and rat skin were proven to contain CK B-type by Western blot analysis. Following exposure to SM ex vivo, the CK-adduct was extracted from homogenates by immunomagnetic separation and proteolyzed afterwards. The cysteine residue Cys282 was found to be alkylated by the SM-specific hydroxyethylthioethyl (HETE)-moiety detected as the biomarker tetrapeptide TC(-HETE)PS. A selective and sensitive micro liquid chromatography-electrospray ionization high-resolution tandem-mass spectrometry (µLC-ESI MS/HRMS) method was developed to monitor local CK-adducts in an in vivo study with rats percutaneously exposed to SM. CK-adduct formation was compared to already established DNA- and systemic albumin biomarkers. CK- and DNA-adducts were successfully detected in biopsies of exposed rat skin as well as albumin-adducts in plasma. Relative biomarker concentrations make the CK-adduct highly appropriate as a local dermal biomarker. In summary, CK or rather Cys282 in CK B-type was identified as a new, additional dermal target of local SM exposures. To our knowledge, it is also the first time that HETE-albumin adducts, and HETE-DNA adducts were monitored simultaneously in an in vivo animal study.

High-Resolution Ultrasound-Guided Perforator Mapping and Characterization by the Microsurgeon in Lower Limb Reconstruction.

BACKGROUND: Preoperative ultrasound (US)-guided perforator mapping has immensely simplified perforator flap planning. It may be executed by the microsurgeon. Device settings and selection of ultrasound modes are of utmost significance for detection of low-flow microvessels. The following study evaluates different US modes. METHODS: A prospective complete data acquisition was performed from July 2018 to June 2019 in a subset of patients who underwent US-guided flap planning. Multifrequency linear transducers were used applying five US modes. Brightness (B)-mode, color flow (CF), power Doppler (PD), pulse wave (PW), and B-flow modes were evaluated regarding applicability by microsurgeons. Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) were chosen to evaluate flow characteristics. US results were correlated to intraoperative findings. RESULTS: A total number of eight patients (six males and two females) undergoing anterolateral thigh (ALT) or superficial circumflex iliac artery perforator (SCIP) flap surgery received an extensive standardized US-guided perforator characterization. Qualitative evaluation was performed in B-mode, color-coded duplex sonography (CCDS), PD, and B-flow mode. Quantitative assessment was executed using PW-mode and CCDS measuring the microvessels' diameter (mm) and flow characteristics (PSV, EDV, and RI). CCDS provided a mean diameter of 1.93 mm (range: 1.2-2.8 ± 0.51), a mean systolic peak of 16.9 cm/s (range: 9.9-33.4 ± 7.79), and mean RI of 0.71 (range: 0.55-0.87 ± 0.09) for lower limb perforators. All perforators located with US were verified by intraoperative findings. An optimized, time-effective US mapping algorithm was derived. Qualitative parameters may be evaluated with B-mode, CF, or B-flow. Smallest microvessels may be assessed in PD-mode. Lowering pulse-repetition frequency (PRF)/scale is mandatory to image low-flow microvessels as perforators. Quantitative information may be obtained using PW-mode and the distance-measuring tool in CF-mode. Image and video materials are provided. CONCLUSION: CCDS proved to be a powerful tool for preoperative perforator characterization when using a structured approach and mapping algorithm. Different techniques may be applied for specific visualizations and performed by the microsurgeon.

Feasibility study of preoperative microvessel evaluation and characterization in perforator flaps using various modes of color-coded duplex sonography (CCDS).

BACKGROUND: Color-coded duplex sonography (CCDS) is useful for perforator flap design showing the highest sensitivity in identifying microvessels. This prospective study evaluates the feasibility of different ultrasound (US) modes applied by the microsurgeon in daily practice suggesting quantifiable reference values. METHODS: Twenty-four patients aged between 17 and 68 years (mean 43.3 ± 14.2 years) with 18 anterolateral thigh (ALT) and 6 superficial circumflex iliac artery (SCIP) flaps were included. Indications were traumatic (n = 12), infectious (n = 6), ischemic (n = 4), or tumor-associated defects (n = 2). Different US modes were evaluated regarding applicability using multifrequency linear probes (5-15 MHz). Vessels diameter, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) were measured. Preoperative results were correlated to intraoperative findings. RESULTS: In the examined patient group with 24 perforator flaps a 100% correlation was seen when comparing perforators detected with CCDS/PD with intraoperative findings using optimized US settings. Sensitivity, PPV, and accuracy of CCDS were 100% respectively. Mean PSV of 16.99 ± 6.07 cm/s, mean EDV of 5.01 ± 1.84 cm/s and RI of 0.7 ± 0.07 were measured in microvessels (PW-mode). CCDS proved to be superior compared to PD in correct diameter assessment showing a mean diameter of 1.65 ± 0.45 mm, compared to PD-mode 1.31 ± 0.24 mm. Mean PSV and EDV were higher in ALT than in SCIP flaps, RI was slightly higher in SCIP flaps (p > .05). There were no significant differences in size of different flaps' perforators (p > .05). CONCLUSION: CCDS represents a highly valuable tool in the daily practice of free flap reconstructions using optimized low flow US settings and multifrequency linear probes.

Pressure distribution and flow characteristics during negative pressure wound therapy.

AIM OF THE STUDY: Negative pressure wound therapy is thought to improve wound healing by altering capillary perfusion. However, despite many theories, the underlying mechanism of action remains controversial. Recent evidence suggests an increased tissue pressure and a temporary decreased microvascular blood flow as the main reasons for the good clinical results [1]. In an attempt to further explain the mechanism of action, we investigated the pressure distribution on the foam interface, and the influence on perfusion in a pre-experimental design. MATERIALS AND METHODS: Pressure distribution was measured using a sensor based on a capacitive dielectric elastomer with flexible electrodes. In vitro flow measurements were done with vessel imitations in a block of 300 bloom ballistic gel to simulate soft tissue. RESULTS: A peak pressure of up to 187 mmHg (255 g/cm2) within the foam interface, as well as decreased perfusion, were found using a standard negative pressure wound therapy setup. In conclusion, negative pressure wound therapy applies positive pressure to adjacent tissue and decreases local flow. The amount of suction applied is proportional to the pressure on the foam interface and reduction in flow. CONCLUSION: In line with previous studies investigating the underlying mechanism of action, these findings may contribute to possible alterations in the use of negative pressure wound therapy, e.g. lowering suction pressure in patients with diminished peripheral blood flow.

An Analysis of Aesthetic Refinements in 120 Secondary Cleft Rhinoplasties.

BACKGROUND: Secondary cleft nose rhinoplasty remains a challenging procedure. Cartilage memory and scar contraction are problematic factors. The need for more detailed procedures for secondary reconstruction in this patient population has arisen. Contemporary refinements demonstrate a highly structured approach. We conducted a retrospective study evaluating the aesthetic results of cleft patients who underwent secondary rhinoplasty. METHODS: In a retrospective study, a photometric analysis of cleft patients operated in the period 2003-2011 was conducted. Reconstructive methods were documented. Pre- and postoperative photographs of cleft rhinoplasty patients were evaluated using a standardized protocol. Nostril width ratio, columellar angle, tip projection ratio, and nasolabial angle served as objective instruments. The Unilateral Cleft Lip Surgical Outcomes Evaluation score was chosen for external photometric rating and rated blindly by 2 external individual plastic surgeons as independent nonbiased reviewers. The interrater and intrarater reliabilities were calculated using the Cohen kappa coefficient (κ). RESULTS: A total of 120 secondary rhinoplasties in 85 uni- and bilateral cleft patients could be included. Mean follow-up was 20 months. A total of 60 (71%) patients needed additional bone grafting (chin/pelvis), and 23 (27%) patients a LeFort I osteotomy. In one third of the secondary rhinoplasties, a medial and/or lateral osteotomy was performed (34%). In one fourth (24%), an external septoplasty was considered necessary. In 55% (47 patients) of the cases, a columellar strut was used. Excluding bone grafts, a total of 173 other grafts (mean of 2 grafts/patient) were applied. Postoperative measurements for nostril width ratio and columellar angle were statistically significant. A structured approach with contemporary refinements is described in detail. Intra- and interrater reliabilities for photometric assessment according to the Unilateral Cleft Lip Surgical Outcomes Evaluation score are shown. CONCLUSIONS: A structured approach for secondary cleft rhinoplasty yields satisfying, reproducible, and stable results.

Oxygen levels during negative pressure wound therapy.

AIM OF THE STUDY: Negative pressure wound therapy (NPWT) has become an established treatment modality when dealing with chronic and infected wounds. The underlying mechanism of action is still under discussion and remains controversial. Evidence exists showing rather hypoxic conditions as the main reason for the positive results and bacterial clearance. In an attempt to further explain the mechanism of action, we investigated oxygen levels within the foam interface of a NPWT device. MATERIALS AND METHODS: We used an optical sensor based on the principle of dynamic fluorescence quenching and tested five different commonly available NPWT systems used during our daily clinical routine. All measurements were done in an in vitro experimental design for at least 24 h and multiple vacuum intensities were investigated. RESULTS: Oxygen levels decreased as much as 22.8% and the amount of vacuum applied inversely correlated with the oxygen reduction. A stepwise increase in vacuum of 25 mmHg showed a linear mean drop of 2.75% per setting. All devices were able to maintain a constant level of negative pressure, and no significant difference between the various dressings was found (p > 0.05). CONCLUSION: Therefore, oxygen levels are decreased within the foam of NPWT dressings, likely leading to oxygen deprivation effects in the underlying wound tissue.

Intraoperative flap design using ICG monitoring of a conjoined fabricated anterolateral thigh/tensor fasciae latae perforator flap in a case of extensive soft tissue reconstruction at the lower extremity.

In this report, we present a case of the use of a conjoined fabricated free anterolateral thigh (ALT)/tensor fascia latae (TFL) perforator flap for reconstruction of the lower extremity with intraoperative flap design using intraoperative indocyanine green (ICG) monitoring. The flap was used for reconstruction of a 16 cm × 28 cm sized defect of the lower leg in a 24-year-old man. The defect was caused by a third degree open fracture to the tibia. Upon dissection of the ALT perforators, ICG monitoring showed that both dominant ALT perforators did not yield a sufficient perforasome (∼16 cm × 17 cm) for the larger flap needed. An adjacent TFL perforator also supplied a large perforasome (∼15 cm × 11 cm), so a conjoined fabricated flap was harvested and transplanted to cover an extensive lower leg defect. The artery of the TFL perforator pedicle was being in-flap anastomosed to a side branch of the ALT pedicle. Postoperative course was uneventful and there were no complications. Length of follow-up was 6 months, aesthetic and functional outcome was good. The patient was very satisfied with the aesthetic outcome. Both legs were fully mobile after intensive physiotherapy for the reconstructed leg. The leg where the flap had been harvested showed full strength in knee joint flexion. This case could show that identification of the supplying vessels may be possible by ICG monitoring. © 2015 Wiley Periodicals, Inc. Microsurgery 36:684-688, 2016.

Combined free flaps with arteriovenous loops for reconstruction of extensive thoracic defects after sternal osteomyelitis.

BACKGROUND: Various local flaps have been described for patients suffering from sternal osteomyelitis and are regarded as a standard procedure for defect reconstruction. In contrast, the use of microsurgical free flaps has been reported anecdotally only. We present our experiences with the combination of an arteriovenous loop and a free flap transfer in defects larger than half of the sternum. METHODS: Between January 2012 and October 2014, eight patients with a mean age of 68 years who suffered from extensive deep sternal osteomyelitis were operated in a consecutive series. After radical surgical debridement, the defect size comprised all three thirds of the sternum. Defect reconstruction was achieved by means of free flap transplantation using the vastus lateralis myocutaneous flap, rectus abdominis, and bipedicled latissimus dorsi/parascapular flap. As local recipient vessels were depleted in all patients, the pedicle of the flap was anastomosed to a high-flow and short-length subclavian arteriovenous loop as recipient vessel in all cases. RESULTS: The immediate postoperative course in all patients was uneventful despite one axonal injury to the femoral nerve at the donor site. There was no partial or total flap loss. During a mean follow-up of 9 months, one patient suffered from a local infection at the donor site. In all patients, a successful defect reconstruction could be achieved. CONCLUSION: Depletion of local recipient vessels as an obstacle for free flap reconstruction can be overcome by creating an arteriovenous loop. Even extensive defects are adequate for defect reconstruction using a single or, in extreme cases, bipedicled free flap.

Results of combined vascular reconstruction and free flap transfer for limb salvage in patients with critical limb ischemia.

OBJECTIVE: Combined vascular reconstruction and free flap transfer has been established in centers as a feasible therapeutic option in cases with critical limb ischemia (CLI) and large tissue defects otherwise destined for major amputation. However, the number of patients treated with this combined approach is limited, and data regarding long-term follow-up and functional outcome are scarce. We therefore report our 10-year experience in free flap transplantation after vascular reconstruction as a last attempt for limb salvage, with special emphasis of complication rate, limb salvage, and postoperative mobility. METHODS: CLI patients undergoing combined vascular reconstruction and consequent free flap transfer from 2003 to 2013 were retrospectively observed. Of 80 cases in total, patients with traumatic and oncologic indications were excluded; 33 (mean age, 66 years; range, 51-82 years) of these cases were performed for limb salvage and were included in this study. Long-term follow-up was possible in 32 of 33 patients (mean, 58 months; range, 2-126 months). RESULTS: Thirty-three patients were analyzed. We performed arterial revascularization with 9 arteriovenous loops, 23 bypass grafts (10 popliteal-pedal, 9 femoral-crural, and 4 femoral-popliteal), and 1 venous interposition graft. For defect coverage, tissue transfer was comprised of six different flap entities (10 latissimus dorsi, 2 gracilis, 1 anterior lateral thigh, 7 rectus abdominis, 11 radialis, and 2 greater omentum flaps). Complications occurred in 16 of 33 patients (49%). Early complications included eight acute occlusions of arterial reconstructions; major bleedings were seen in eight patients as well. There were two flap losses and one major amputation in the early postoperative period. No in-hospital deaths were observed. Late results revealed a limb salvage rate of 87% after 1 year and 83% after 5 years. Amputation-free survival was 87% after 1 year and 75% after 5 years. Overall survival was 100% and 87% after 1 year and 5 years, respectively. Follow-up showed 42% of patients with no limitations in ambulation, 54% with maintained preoperative ambulatory status, and one bedridden patient. CONCLUSIONS: The combined approach for limb salvage in CLI patients is associated with excellent results in limb salvage and functional outcome in patients who would otherwise be candidates for major amputation, despite an initially elevated complication rate. The option of combined revascularization with free tissue transfer should be evaluated in all mobile patients with CLI, large tissue defects, and exposed tendon or bone structures before major amputation. However, further studies are required to support these results.

Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life, Complications and Comorbidities after DIEP or ms-TRAM Flap Using the BREAST-Q.

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri- and post-operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen-Nuernberg were surveyed at least 6 month postoperative using the BREAST-Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre-existing diseases and the choice of DIEP versus ms-TRAM flaps. Parameters such as major and minor complications, bulging or hernia and risk factors (e.g. smoking or obesity) showed no significant differences. The results of the questionnaire parameters showed no significant difference between both groups, revealing high satisfaction with the aesthetic result and an improvement in quality of life independent of age. Autologous breast reconstruction after mastectomy generates a gain in quality of life and shows a good to excellent overall satisfaction in older as well as younger patients. Despite a longer hospitalization and a different risk profile there were no significant differences regarding minor and major complications in the postoperative course. Hence autologous breast reconstruction for older patients is justified and should be taken into consideration.

Emergency arterio-venous loop for free-flap defect reconstruction of the lower thigh with a post-irradiated and heavily infected wound.

Although being a safe and standardised procedure, free-flap reconstruction can be harmful if unpredictable situations occur intraoperatively. The case presented reveals a situation in which an unscheduled interdisciplinary approach allowed to complete our reconstructive aim. An extensive defect at the thigh was planned for reconstruction by means of a free rectus abdominis flap. As the distant part of the flap showed a compromised perfusion during operation and had to be partially discarded, our colleagues from the vascular surgery department created an arterio-venous loop for anastomosis. This allowed a more distant positioning of the flap and ensured a complete defect reconstruction.

Ischaemia-related cell damage in extracorporeal preserved tissue - new findings with a novel perfusion model.

Tissue undergoing free transfer in transplant or reconstructive surgery always is at high risk of ischaemia-related cell damage. This study aims at assessing different procedures using an extracorporeal perfusion and oxygenation system to investigate the expression of hypoxia inducible factor (HIF)-1-α as marker for hypoxia and of the pro-apoptotic protein Caspase-3 in skeletal muscle to elucidate potential improvements in tissue conservation. Twenty-four porcine rectus abdominis muscles were assigned to five different groups and examined after they had been extracorporeally preserved for 60 min. time. Group I was left untreated (control), group II was perfused with a cardioplegic solution, group III was flushed with 10 ml of a cardioplegic solution and then left untreated. Group IV and V were perfused and oxygenated with either an isotone crystalloid solution or a cardioplegic solution. Among others, immunohistochemistry (Caspase-3 and HIF-1-α) of muscle samples was performed. Furthermore, oxygen partial pressure in the perfusate at the arterial and venous branch was measured. Expression of Caspase-3 after 60 min. was reduced in all groups compared to the control group. Furthermore, all groups (except group III) expressed less HIF-1-α than the control group. Oxygenation leads to higher oxygen levels at the venous branch compared to groups without oxygenation. Using an extracorporeal perfusion and oxygenation system cell damage could be reduced as indicated by stabilized expressions of Caspase-3 and HIF-1-α for 60 min. of tissue preservation. Complete depletion of oxygen at the venous branch can be prevented by oxygenation of the perfusate with ambient air.

Comparing the effectiveness of novel high-end compression garment with common compression garment and kinesio tape in preventing edema and improving tissue perfusion in lower extremities.

CONTEXT: Global sales of compression garments have risen sharply in recent years. Due to the availability of a wide range of compression garments, this study aims to evaluate the effect of two types of compression garments and kinesio tape on edema formation and tissue perfusion in the lower extremities. Over-the-counter compression knee stockings and kinesio tape were compared with a prototype of high-end compression stockings that combine kinesio tape and a common knee bandage. The high-end compression stockings were designed by Cube with the aim of combining the positive effects of kinesio tape and compression garments on edema formation and tissue perfusion. DESIGN: Clinical cross-over study. METHODS: Before and after a 6-hour compression period, the knee regions on both, the treated and non-treated leg, of participants were examined using a 3-D scan to detect changes in volume. Also measured were local temperature (°C), oxygen saturation (SpO2), perfusion index (Pi), blood pressure (mmHg), compression pressure (mmHg), range of motion, body-mass-index (BMI) and limb-circumference (cm). Two different types of compression garments were examined: a novel high-end compression stocking (A) and a common compression stocking (B). In addition, kinesio tape was compared to compression garments (C). After each experimental day, a one-day break was taken to prevent an unwanted overlay effect. Male and female participants between the ages of 18 and 60 were randomly selected. RESULTS: The high-end compression garment (A) showed a statistically significant (P = 0.009) reduction of edema intraindividually. Comparing the three treatment groups, compression (A) lead to a reduction of edema. However, the reduction was not statistically significant (P = 0.585). The compression garment B and kinesio tape showed an increase in edema in the lower limb. There was a positive correlation between the highest compression pressure (A: 9.8 mmHg) and volume decrease over the period of 6 hours. Lighter compression (B: 8.2 mmHg) led to an increase in leg volume after compression application over 6 hours. There was no significant difference in tissue oxygen saturation with the two types of compression and kinesio tape. The tissue temperature below the compression garment was highest in the compression group A. Nevertheless, we could not demonstrate a statistically significant correlation between tissue temperature and volume difference.The range in motion of the lower limb decreased after 6 hours with both compression A and B and with kinesio tape. CONCLUSION: The novel bandage showed a statistically significant reduction in edema when compared intraindividually, but no statistically significant advantage was found when compared with the other compression garment B and kinesio tape.Despite the widespread use of kinesio tape, we did not find any improvement in the range of motion, edema prevention and circulation in the lower limb after application of kinesio tape.

Negative Pressure Wound Therapy-A Vacuum-Mediated Positive Pressure Wound Therapy and a Closer Look at the Role of the Laser Doppler.

Background: Negative pressure wound therapy (NPWT) is an intensely investigated topic, but its mechanism of action accounts for one of the least understood ones in the area of wound healing. Apart from a misleading nomenclature, by far the most used diagnostic tool to investigate NPWT, the laser Doppler, also has its weaknesses regarding the detection of changes in blood flow and velocity. The aim of the present study is to explain laser Doppler readings within the context of NPWT influence. Methods: The cutaneous microcirculation beneath an NPWT system of 10 healthy volunteers was assessed using two different laser Dopplers (O2C/Rad-97®). This was combined with an in vitro experiment simulating the compressing and displacing forces of NPWT on the arterial and venous system. Results: Using the O2C, a baseline value of 194 and 70 arbitrary units was measured for the flow and relative hemoglobin, respectively. There was an increase in flow to 230 arbitrary units (p = 0.09) when the NPWT device was switched on. No change was seen in the relative hemoglobin (p = 0.77). With the Rad-97®, a baseline of 92.91% and 0.17% was measured for the saturation and perfusion index, respectively. No significant change in saturation was noted during the NPWT treatment phase, but the perfusion index increased to 0.32% (p = 0.04). Applying NPWT compared to the arteriovenous-vessel model resulted in a 28 mm and 10 mm increase in the venous and arterial water column, respectively. Conclusions: We suspect the vacuum-mediated positive pressure of the NPWT results in a differential displacement of the venous and arterial blood column, with stronger displacement of the venous side. This ratio may explain the increased perfusion index of the laser Doppler. Our in vitro setup supports this finding as compressive forces on the bottom of two water columns within a manometer with different resistances results in unequal displacement.