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.

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.

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.

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.

Negative Pressure Wound Therapy with Instillation: Analysis of the Rinsing Fluid as a Monitoring Tool and Approach to the Inflammatory Process: A Pilot Study.

BACKGROUND: Negative pressure wound therapy with instillation (NPWTi) is an established wound conditioning tool. Previous investigations discovered that the rinsing fluid is a suitable monitoring tool containing various cells and cytokines. METHODS: The aim of this pilot study was to analyze rinsing fluid samples from patients treated with NPWTi and link them to the clinical course, including microbiological contamination. In 31 consecutive patients with acute and chronic wounds, laboratory analysis was performed to evaluate IL-6, IL-8, bFGF, Tnf-a, and VEGF. RESULTS: IL-6 showed a significant increase to 1540 pg/mL on day two and 860 pg/mL on day four (p = 0.01 and p = 0.04, resp.). IL-8 steadily increased from a median of 2370 pg/mL to a maximum of 19,400 pg/mL on day three (p = 0.01). The median bFGF showed a steady decline from 22 pg/mL to 10 pg/m (p = 0.35) on day three. The median Tnf-a increased from 11 pg/mL to 44 pg/mL (p = 001). The median VEGF values fluctuated but showed an overall increase from 35 pg/mL to 250 pg/mL (p = 0.07). Regarding IL-8, diabetic and non-diabetic patients both showed a gradual increase with non-significant higher median values for the diabetics. The subgroup analysis of IL-6 showed increasing and higher values in cases with bacterial superinfections (p = 0.07). CONCLUSION: We were able to use an established wound conditioning tool to gather important information about the inflammatory response during NPWTi treatment. Cytokine and cell courses were mostly consistent with the literature, especially in diabetic patients, and should be further investigated.

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.

Quality of life evaluation and lack of correlation with volumetric results after lymphovenous anastomoses in lymphedema therapy of the lower extremity.

OBJECTIVE: Chronic primary or secondary lymphedema has huge effects on patients' quality of life (QOL) because of the associated swelling and pain, decreased range of motion, and depression and anxiety and generally requires numerous adaptations. Many studies have shown a positive objective effect of lymphovenous anastomoses (LVAs) on chronic lymphedema. In the present study, we assessed the effect of LVAs on QOL in patients with primary or secondary lymphedema of the lower extremity at 6 months after surgery and examined the correlation between changes in the QOL and volumetric measurements. METHODS: Only patients with either primary or secondary lymphedema of the lower extremity who had undergone LVAs were included in the present study. To assess QOL, a specially designed questionnaire based on the Lymphedema Quality of Life Inventory was used to evaluate the subjective therapeutic results from the patients' perspective. Objective therapy success was assessed using three-dimensional volumetric measurements of the lower leg. The measuring points, for both the subjective and the objective measurements, were the day before and 6 months after therapy. RESULTS: The mean change in volume at 6 months after LVA was -6.5% ± 5.6% (P < .001). Significantly better QOL in terms of physical (37.6% ± 25.2%) and psychosocial (27.0% ± 43.0%) domains and practical restrictions (22.3% ± 24.8%) was found (P < .001 for all). No correlation was found between QOL improvement and volume decrease (P > .05). CONCLUSIONS: For patients with lymphedema of the lower extremity, LVAs can lead to a significant volumetric decrease and QOL improvement at 6 months after treatment with no demonstrable relationship between QOL improvement and volume reduction.

Analysis of Rinsing Fluid during Negative Pressure Wound Therapy with Instillation: A Potential Monitoring Tool in Acute and Chronic Wound Treatment. A Pilot Study.

BACKGROUND: During negative pressure wound therapy (NPWT), open wounds are draped with a nontransparent sponge, making daily wound evaluation impossible. Sometimes, late or undetected bacterial infections and postoperative bleeding result in repetitive surgery, thus prolonging inpatient time. With the introduction of additional fluid instillation (NPWTi), the wound surface is rinsed, and bacteria, proteins and biomarkers are flushed into a collecting canister, which is later discarded. METHODS: The aim of this pilot study was to analyze rinsing fluid samples (0.9% sodium chloride) from the NPWTi device in patients with acute and chronic wounds. In 31 consecutive patients a standardized laboratory analysis was performed to evaluate cellular composition and potassium, phosphate, lactate dehydrooxygenase, pH and total protein levels. RESULTS: While there was an increase in the total cellular amount and the number of polymorphonuclear cells, the number of red blood cells (RBC) decreased after surgery. Potassium and pH showed no significant changes in the first three postoperative days, whereas total protein showed an undulant and partially significant course. CONCLUSION: We were able to quantify cellular metabolites by analyzing the rinsing fluid of NPWTi. We propose the analysis of this material as a novel and potentially promising tool to monitor wound status without removal of the dressing. The establishment of reference values might help to improve the NPWTi therapy.

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.

Extracorporeal perfusion - reduced to a one-way infusion.

BACKGROUND: Extracorporeal perfusion (EP) is moving into focus of research in reconstructive and transplantation medicine for the preservation of amputates and free tissue transplants. The idea behind EP is the reduction of ischemia-related cell damage between separation from blood circulation and reanastomosis of the transplant. Most experimental approaches are based on a complex system that moves the perfusate in a circular course. OBJECTIVE AND METHODS: In this study, we aimed to evaluate if a simple perfusion by an infusion bag filled with an electrolyte solution can provide acceptable results in terms of flow stability, oxygen supply and viability conservation for EP of a muscle transplant. The results are compared to muscles perfused with a pump system as well as muscles stored under ischemic conditions after a one-time intravasal flushing with Jonosteril. RESULTS: With this simple method a sufficient oxygen supply could be achieved and functionality could be maintained between 3.35 times and 4.60 times longer compared to the control group. Annexin V positive nuclei, indicating apoptosis, increased by 9.7% in the perfused group compared to 24.4% in the control group. CONCLUSIONS: Overall, by decreasing the complexity of the system, EP by one-way infusion can become more feasible in clinical situations.

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.

Tissue Viability of Free Flaps after Extracorporeal Perfusion Using a Modified Hydroxyethyl Starch Solution.

BACKGROUND: In free flap surgery, tissue is stored under hypothermic ischemia. Extracorporeal perfusion (EP) has the potential to extend storage time and the tissue's perspective of survival. In the present study, the aim is to improve a recently established, simplified extracorporeal perfusion system. METHODS: Porcine musculus rectus abdominis were stored under different conditions. One group was perfused continuously with a simplified one-way perfusion system for six hours, while the other received only a single flush but no further treatment. A modified hydroxyethyl starch solution was used as a perfusion and flushing solution. Vitality, functionality, and metabolic activity of both groups were analyzed. RESULTS: Perfused muscles, in contrast to the ischemically stored ones, showed no loss of vitality and significantly less functionality loss, confirming the superiority of storage under continuous perfusion over ischemic storage. Furthermore, in comparison to a previous study, the results were improved even further by using a modified hydroxyethyl starch solution. CONCLUSION: The use of EP has major benefits compared to the clinical standard static storage at room temperature. Continuous perfusion not only maintains the oxygen and nutrient supply but also removes toxic metabolites formed due to inadequate storage conditions.

The influence of pulsed electromagnetic field therapy (PEMFT) on cutaneous blood flow in healthy volunteers1.

BACKGROUND: The biophysical interaction induced by low energy pulsed electromagnetic field therapy (PEMFT) on the capillary microcirculation is not well understood. Several studies indicate a significant effect of PEMFT in patients with chronic medical conditions. OBJECTIVE: The aim of this study was to evaluate the influence of PEMFT on skin microcirculation in healthy volunteers. METHODS: 15 healthy participants were included. Nine PEMF treatments were applied over three weeks in an 48-hour interval. The PEMFT system (BEMER) was placed beneath one of the participants' leg with the contralateral side serving as a control. A forty-minute application period was preceded by a 10-minute resting phase. Measuring was done using two Laser Doppler probes (LEA) placed on each anterior lateral thigh. RESULTS: All outcome parameters including flow, mixed venous oxygen saturation and relative venous hemoglobin showed a significant increase during the experiment when compared to the baseline values of the resting phase in both groups (p < 0.01). Comparing both groups, the measurement values during the experiment did not differ (p > 0.05) except for higher flow values in the control group (P = 0.03). Over time, baseline values of both groups showed no significant difference (p > 0.05). CONCLUSION: We found a significant increase of all measurement parameters during the study compared to the baseline values with no difference between the PEMF and control group.

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.

[Economic factors in microsurgery - Report of the consensus workshop of the German-Speaking Society for Microsurgery of Peripheral Nerves and Vessels - (DAM)]. / Wirtschaftliche Aspekte in der Mikrochirurgie: Bericht zum Konsensus-Workshop der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße ­ (DAM).

In addition to outcome assessments, cost effectiveness of surgical treatments becomes increasingly important. Both, insurance companies and hospital administrations aim for short and efficient procedures to reduce costs.Microsurgical procedures are often surpassing traditional treatment options in terms of function and aesthetics. However, they are more expensive as they require a high level of surgical expertise, more theatre capacity and longer inpatient treatment. Adequate reimbursement is mandatory, if we want to continuously perform these procedures with the best possible quality and outcome. To cover the case-related expenses of each specialty, multidisciplinary procedures require appropriate distribution of reimbursements to each department.The main diagnosis as well as all complications and relevant comorbidities should be documented to obtain the correct DRG. The additional financial benefit of a microsurgical procedure in a multidisciplinary case can be calculated by specifying the procedural increment in pay. Therefore, a fair distribution of revenues to each participating department should be performed. Different models exist, which lead to a benefit in compensation for all departments. Unfortunately, distribution of resources is still insufficiently managed in many hospitals, which hampers high quality multidisciplinary microsurgical procedures. Still, picking the best possible procedure for our patients, independently of financial incentives, is of utmost importance.

Step-by-step guide to ultrasound-based design of alt flaps by the microsurgeon - Basic and advanced applications and device settings.

BACKGROUND: The anterolateral thigh (ALT) perforator flap is a popular reconstructive tissue transfer. Consistent with the "hot/cold zone" concept for rapid dissection and thin flap harvest, reliable preoperative perforator mapping is mandatory. Color-coded duplex sonography (CCDS) has been shown to have the highest pooled sensitivity and positive predictive value to identify ALT perforating vessels. By reviewing this guide, the reader should learn: 1. Probe selection and basic/advanced device settings 2. Interpreting tissue morphology 3. Structured mapping approach 4. Pedicle position planning 5. Safe flap design 6. Assess subcutaneous course and flap's thickness for subfascial/epifascial/suprafascial harvest 7. Implement perforators identified into a tailor-made flap design including chimeric flaps. METHODS: Experiences with ultrasound-guided flap design gained from 125 ALT perforator flap free tissue transfers performed in two reconstructive centers was the basis of our guide. Our structured method comprises standardized markings, patient positioning, and simple ergonomics. Basic and advanced CCDS settings, selection, and conventional probe guidance are outlined for the microsurgeon. RESULTS: Linear multifrequency probes (6-15 MHz) were used. Best preset programs were breast, thyroid, and vascular. Favorable device properties were depth focused to 2-5 cm, pulse repetition frequency (PRF/Scale) set low to 0.5-1.5 kHz/3-10 cm/s, color gain high, and wall filter (WF) low/off (< 50 Hz). Additional parameters were discussed. A 100% concordance rate was seen comparing preoperative perforator visualization with CCDS and intraoperative findings. Detailed picture and video material were demonstrated. CONCLUSION: CCDS is a powerful tool for preoperative perforator mapping in perforator flaps such as the ALT.

The Influence of Pulsed Electromagnetic Field Therapy on Lymphatic Flow During Supermicrosurgery.

Background: The influence of pulsed electromagnetic field therapy (PEMFT) on medium-sized vessels as well as capillary microcirculation is well known. Effects on lymphatic vessels, however, are difficult to visualize and have not been investigated to date. One of the operative treatment options in primary and secondary lymphedemas is lymphovenous anastomoses using supermicrosurgery. To prove patency of the anastomosis, the lymphatic flow is visualized by fluorescence using indocyanine green. The aim of this study was to investigate the influence of PEMFT on the lymphatic microcirculation, and compare it with conventional manual lymphatic drainage (MLD) during supermicrosurgery. Methods and Results: Ten patients with lymphedema were included. Indocyanine green was injected before the operation for intraoperative visualization of the lymphatic vessels using a microscope equipped with an integrated near-infrared illumination system (Zeiss). The PEMFT system (Bio-Electro-Magnetic-Energy Regulation [BEMER]) was used as our standard device during a single 2-minute application period (AP) followed by MLD or vice versa. The mean light intensity in the calibration period (CP) was 46.53 ± 24.3 and 33.41 ± 12.92 for PEMFT and MLD, respectively. During the AP, the mean light intensity changed to 45.61 ± 24.40 for PEMFT and 57.05 ± 18.80 during MLD. This change between CP and AP did not differ significantly for the PEMFT application (p = 0.26), but showed an increase in light intensity during MLD (p < 0.001). Conclusion: We found a light intensity enhancement equivalent to a flow increase during MLD of 78.7% ± 45.7% (range 20%-144%) and no significant difference during the PEMFT application. A single period application of PEMFT did not affect the lymphatic flow.

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.