How to Start and Build Microsurgery Practice-Topics on Success and Sustainability: Global/International.

Many young microsurgeons begin their careers at established hospitals where microsurgery resources are limited. This article shares the authors' experiences in overcoming challenges and establishing a microsurgery practice in a new hospital. Due to the lack of equipment, limited support from colleagues, absence of discussion partners, fear of failure, and unpredictable situations, many aspiring microsurgeons lose their motivation. The purpose of this article is to guide future microsurgeons by describing the author's actions and suggesting improvements for their first free flap case. Key factors for building a successful, sustainable, and enjoyable microsurgery practice include remembering your training and mentors, acquiring fundamental knowledge of microsurgery, creating a supportive ecosystem, and having fun.

Identifying Functional Lymph Nodes in Lower Extremity Lymphedema Patients: The Role of High-frequency Ultrasound.

BACKGROUND: Lymph nodes may play a potential role in lymphedema surgery. Radiologic evaluation of nodes may reveal the status of pathologic conditions but with limited accuracy. This study is the first to evaluate the efficacy of ultrasound in detecting functioning nodes in lymphedema patients and presents a criterion for determining the functionality of the lymph nodes. METHODS: This retrospective study reviews 30 lower extremity lymphedema cases which were candidates for lymph node to vein anastomosis. Lymphoscintigraphy and magnetic resonant lymphangiography (MRL) imaging were compared with ultrasound features which were correlated to intraoperative indocyanine green (ICG) nodal uptake as an indication of functionality. RESULTS: Majority were International Society of Lymphology stage 2 late (50.0%) and stage 3 (26.7%). ICG positive uptake (functioning nodes) was noted in 22 (73.3%), while 8 patients (26.6%) had negative uptake (nonfunctioning). Ultrasound had significantly the highest specificity (100%) for identifying functional nodes followed by lymphoscintigraphy (55%) and MRL (36%; p = 0.002, p < 0.001, respectively). This was associated with 100% positive predictive value compared against lymphoscintigraphy (44%) and MRL (36%; p < 0.001 for both). The identified ultrasound imaging criteria for functioning lymph node were oval lymph node shape (Solbiati Index), morphology, vascularity pattern, and vascularity quantification. CONCLUSION: The use of ultrasound in nodal evaluation was proven effective in different pathologic conditions and demonstrated the best prediction for functionality of the lymph node based on the new evaluation criteria.

Comparative Study of Small Vessel (under 0.8 mm) Anastomosed Free Flap and Larger Vessel (over 0.8 mm) Anastomosed Free Flap; Does Supermicrosurgery Provide Sufficient Blood Flow to the Free Flap?

BACKGROUND: This study aimed to quantify the blood flow of free flaps and compare the blood flow of small vessel (<0.8 mm) and larger vessel (>0.8 mm) anastomosed free flaps. METHODS: This retrospective study included patients treated successfully with a perforator free flap in the lower extremity between June 2015 and March 2017. A color duplex ultrasound system measured the flow volume through the pedicle by analyzing the mean flow peak velocity, flow volume, and flow volume per 100 g of the flap. RESULTS: A total of 69 patients were enrolled in this study. There was no statistical difference in peak velocity between the small vessel anastomosed free flap (25.2 ± 5.6) and larger vessel anastomosed free flap (26.5 ± 5.4). Flow volume (6.8 ± 4.2 vs. 6.3 ± 3.6) and flow volume/100 g (3.6 ± 3.9 vs. 6.2 ± 6.9) also did not show significant differences. CONCLUSION: Small vessel (<0.8 mm) free flaps showed similar flow velocity and flow volume to larger vessel (>0.8 mm) anastomosed free flaps. Blood flow to the small vessel anastomosed free flap was sufficient despite its small vessel size.

Effect of a portable light emitting diode device on wound healing in a rat model.

Light-emitting diode (LED) lights produce a variety of wavelengths that have demonstrable efficacy in therapeutic and aesthetic fields. However, a repetitive treatment regimen is required to produce treatment outcomes, which has created a need for portable LED devices. In this study, we aimed to develop a portable therapeutic LED device and investigate its healing effect on excisional wounds in a rat model. The 35 × 35 mm-sized LED device was used on a total of 30 rats with full-thickness wounds that were divided into two groups depending on radiation intensity (11.1 and 22.2 mW/cm2 group). LED irradiation was performed every 24 h for 30 min, over 14 days, in direct contact with the wound. Percentage wound closure was measured by photographic quantification and was assessed histologically using haematoxylin and eosin (H&E) and Masson's Trichrome staining, and immunohistochemistry for Vascular endothelial growth factor (VEGF) and CD31. Percentage wound closure was significantly higher in 22.2 mW/cm2 irradiated wounds than that in the control wounds on days 7 and 10. The area of collagen deposition was remarkably larger in 22.2 mW/cm2 irradiated wounds than that in the control, with more horizontally organized fibres. CD31 immunostaining confirmed a significant increase in the number of microvessels in 22.2 mW/cm2 irradiated wounds than that in the control wounds, although there was no difference in VEGF immunostaining. Our novel portable LED device accelerates wound healing in a rat model, raising the possibility that portable LED devices can combine convenience with accessibility to play an innovative role in wound dressing.

Further insight in selecting the ideal vein for lymphaticovenous anastomosis: utilizing the anatomy and Venturi effect of a small vein/venule draining into the main vein.

INTRODUCTION: The functional and dilated lymphatic vessel and veins with minimal backflow and pressure are considered ideal for lymphaticovenous anastomsosis (LVA). However, how to select the ideal vein remains to be determined. This study aims to provide further insight in selecting the ideal vein. MATERIAL AND METHODS: This is a retrospective study evaluating 166 limbs with lymphedema with a minimal follow-up period of 12 months. The surgical approach included side-to-end LVA where one group used a non-Venturi LVA and the other used a small branch draining into a major vein (Venturi LVA). Preoperative, postoperative 1, 3, 6, 12 months limb volume, circumference, reduction volume and ratio were evaluated. RESULTS: The postoperative volume reduction was significant for both groups when compared to their respective preoperative volume. When compared between the 2 groups, the Venturi LVA had a significantly higher reduction volume and ratio at postoperative 1 month (240.82±260.73 cm³ vs 364.27±364.08 cm³, 6.13±5.62% vs 8.77±6.64%; p<0.05) and at 3 months (289.19±291.42 cm³ vs 432.50±395.04cm³, 7.31 ± 6.39% vs 10.55 ± 6.88%; p<0.05) However, the reduction volume and ratio was not significant towards month 6 and 12. CONCLUSION: This study provides further insight in selecting the ideal vein for LVA. By using a small vein draining into the main vein, valves play a role in reducing backflow. Furthermore, the Venturi effect allows significantly enhanced drainage especially in the initial period after surgery. The effect slowly plateaus after few months ultimately having a similar outcome of reduction at 12 months.

Hybrid Bionic Nerve Interface for Application in Bionic Limbs.

Intuitive and perceptual neuroprosthetic systems require a high degree of neural control and a variety of sensory feedback, but reliable neural interfaces for long-term use that maintain their functionality are limited. Here, a novel hybrid bionic interface is presented, fabricated by integrating a biological interface (regenerative peripheral nerve interface (RPNI)) and a peripheral neural interface to enhance the neural interface performance between a nerve and bionic limbs. This interface utilizes a shape memory polymer buckle that can be easily implanted on a severed nerve and make contact with both the nerve and the muscle graft after RPNI formation. It is demonstrated that this interface can simultaneously record different signal information via the RPNI and the nerve, as well as stimulate them separately, inducing different responses. Furthermore, it is shown that this interface can record naturally evoked signals from a walking rabbit and use them to control a robotic leg. The long-term functionality and biocompatibility of this interface in rabbits are evaluated for up to 29 weeks, confirming its promising potential for enhancing prosthetic control.

The Quality of Life after Lymphaticovenous Anastomosis in 118 Lower Limb Lymphedema Patients.

Background This is a prospective study on 118 patients who underwent lymphaticovenous anastomosis (LVA) due to secondary lower limb lymphedema between January 2018 and October 2020 to evaluate patients' quality of life (QOL) using the Quality of Life Measure for Limb Lymphedema (LYMQoL) questionnaire. Methods The outcome measurement included the LYMQoL leg scoring system tool evaluating the function, appearance, symptom, mood, and overall outcome. In addition, correlation analysis was performed for three factors: based on International Society of Lymphology (ISL) stages, disease duration, and amount of volume reduction. Results The LYMQoL tool overall satisfaction score significantly increased at all intervals from 4.4 ± 0.2 preoperative to 6.5 ± 0.3 postoperative at 12 months ( p < 0.001). Significant findings were seen for each domain scores compared preoperatively and at 12 months: function score (18.6 ± 0.5 to 15.4 ± 0.6), appearance score (17.8 ± 0.5 to 16.0 ± 0.6), symptom score (11.8 ± 0.3 to 8.9 ± 0.4), and mood score (14.5 ± 0.4 to 11.4 ± 0.5; p < 0.05). The correlation analysis between improvement of the overall score and the ISL stage ( p = 0.610, correlation coefficient [ r ] = - 0.047), disease duration ( p = 0.659, r = - 0.041), and amount of limb volume reduction ( p = 0.454, r = - 0.070) showed no statistical significance. Conclusion The QOL of secondary lower limb lymphedema patients was significantly improved after LVA regardless of the severity of disease, duration of disease, and amount of volume reduction after LVA. Understanding the patient-reported outcome measurement will help the surgeons to manage and guide the expectations of the patients.

"Color Contrast" Technique using 10 % Sodium Fluorescein and Blue Marker to Maximize Visualization During Lymphaticovenous Anastomosis.

Lymphatics vessel wall and lumen visualization during anastomosis process is quite challenging for which different techniques were described with variable efficacy. Double opposing color contrast is created using 10% Sodium Fluorescein (FS) which stains lymphatic fluid with yellow causing a clear contrast to blue marker painted lymphatic wall improving the intra-lumen visualization during anastomosis process. This retrospective study evaluated the success rate of performing anastomosis between the side of the lymphatic vessel to the end of the vein (S-to-E LVA) for 281 patients. The LVA assessment showed mean lymphatic diameter of 0.44±0.09mm and mean vein diameter of 0.57±0.14mm with S-to-E success rate of 100% confirmed by post-anastomosis Indocyanine green lymphography. No adverse events were encountered, and FS was not used in two patients due to positive skin allergy test. This method has the advantages of not needing additional device, allows clear visualization and not staining the surrounding structures. This approach using opponent color contrast between fluorescent yellow and blue marker improved vessel edge identification which translated into higher visualization and patency with 100% success rate in S-to-E LVA performance.

The Role of Escin as a Topical Agent for Lymphedema Treatment in a Rat Model.

Escin, a naturally derived material isolated from horse chestnut, is used as an anti-inflammatory and anti-edema agent. This study aimed to evaluate its effects on lymphedema in a rat tail model. We divided the rats into five groups. The treatment groups received topical application of escin gel at concentrations of 20%, 10%, 2%, and 0.5% for 4 weeks. The fifth group served as a control. We performed volumetric (water displacement) tests, H&E staining, and LYVE-1 immunohistochemical staining, followed by statistical evaluation. All treatment groups showed significant volumetric reductions compared with the control group, but no significant differences were observed between the treatment groups. H&E staining showed a significant reduction in dermal thickness in the 20%, 10%, and 2% escin treatment groups compared to the control group. Within the treatment groups, the 2% escin group showed a significant difference compared with the 20% and 10% escin groups (p = 0.021 for both). LYVE-1 immunohistochemical staining revealed a significantly higher mean lymphatic vessel count in the 2% escin group compared with the 20%, 10%, and 0.5% escin-treated groups and the control group (p = 0.019, p = 0.025, p = 0.019, and p = 0.032 respectively). Topical escin applied to a rat tail model of acute lymphedema resulted in a significant reduction in tail volume, reduced dermal thickness, and increased lymphatic structures. The 2% escin concentration may be the optimal dose for improving lymphedema in this model. Further research is warranted to explore the clinical application of escin in patients with lymphedema.

In Vivo Dynamic and Static Analysis of Lymphatic Dysfunction in Lymphedema Using Near-Infrared Fluorescence Indocyanine Green Lymphangiography.

BACKGROUND: Near-infrared fluorescence indocyanine green lymphangiography, a primary modality for detecting lymphedema, which is a disease due to lymphatic obstruction, enables real-time observations of lymphatics and reveals not only the spatial distribution of drainage (static analysis) but also information on the lymphatic contraction (dynamic analysis). METHODS: We have produced total lymphatic obstruction in the upper limbs of 18 Sprague-Dawley rats through the dissection of proximal (brachial and axillary) lymph nodes and 20-Gy radiation (dissection limbs). After the model formation for 1 week, 9 animal models were observed for 6 weeks using near-infrared fluorescence indocyanine green lymphangiography by injecting 6-µL ICG-BSA (indocyanine green-bovine serum albumin) solution of 20-µg/mL concentration. The drainage pattern and leakage of lymph fluid were evaluated and time-domain signals of lymphatic contraction were observed in the distal lymphatic vessels. The obtained signals were converted to frequency-domain spectrums using signal processing. RESULTS: The results of both static and dynamic analyses proved to be effective in accurately identifying the extent of lymphatic disruption in the dissection limbs. The static analysis showed abnormal drainage patterns and increased leakage of lymph fluid to the periphery of the vessels compared with the control (normal) limbs. Meanwhile, the waveforms were changed and the contractile signal frequency increased by 58% in the dynamic analysis. Specifically, our findings revealed that regular lymphatic contractions, observed at a frequency range of 0.08 to 0.13 Hz in the control limbs, were absent in the dissection limbs. The contractile regularity was not fully restored for the follow-up period, indicating a persistent lymphatic obstruction. CONCLUSIONS: The dynamic analysis could detect the abnormalities of lymphatic circulation by observing the characteristics of signals, and it provided additional evaluation indicators that cannot be provided by the static analysis. Our findings may be useful for the early detection of the circulation problem as a functional evaluation indicator of the lymphatic system.

Decompression of Axillary vein - An essential adjunct for advanced lymphedema.

INTRODUCTION: In advanced lymphedema, lymphovenous anastomosis (LVA) can be a solution based on utilizing the pressure gradient between the high pressure lymphatics and low pressure veins. If the vein pressure in high, the effect affect surgery will be less optimal. This study evaluated the effect of axillary vein perivascular scar release on LVA. MATERIALS AND METHODS: This is a retrospective study of 40 upper limb stage 2 and 3 lymphedema patients divided into 2 groups with an average follow-up of 33 months (minimal of at least 12 months); scar-released group (n=25) and control group (n=15). All patients underwent LVA with or without lymph node transfer. Demographic data, outcome (volumetric change and bioimpedence analysis (BIA)), and major veins (axillary, basilic and cephalic) diameter changes were evaluated. RESULTS: Both groups showed significant reduction in volume and BIA parameters after LVA. The scar-released groups (24/25 with lymph node transfer and 1 without) showed statistically higher reduction of BIA analysis compared to the control group at 1, 6 and 12 months after LVA. The changes in the major veins after axilla scar release showed significant changes in all 3 veins. There was a significant correlation between cephailic vein dimeter reduction and BIA measurement. CONCLUSION: The release of perivascular scar in the axially vein may result in better outcome after LVA. This is based on the finding that scar release shows correlation between cephailic vein dimeter reduction and BIA measurement suggesting reduction of venous pressure in the peripheral vein increasing the pressure gradient between the lymphatic and venous system allowing better outflow after LVA.

Effect of body habitus on surgical outcomes following bilateral axillo-breast approach robotic thyroidectomy: a retrospective cohort study.

INTRODUCTION: BMI has been shown to predict perioperative outcomes in patients undergoing surgery. Most studies assessing the role of body habitus in thyroid surgery have focused on open surgery, with few studies assessing patients undergoing robotic surgery. The present study evaluated the effects of BMI on surgical outcomes in patients undergoing bilateral axillo-breast approach (BABA) robotic thyroidectomy. MATERIALS AND METHODS: This study included patients who underwent BABA robotic thyroidectomy between January 2013 and September 2021 at Seoul National University Bundang Hospital. Patients were categorized into six groups based on the WHO classification of overweight and obesity. Clinicopathological characteristics, postoperative complications, and surgical outcomes were evaluated. RESULTS: A total of 1921 patients were included. Comparisons of the six BMI groups showed no statistically significant differences in postoperative stay, resection margin involvement, postoperative complications, and recurrence. Subgroup analysis showed that hypocalcemia rates differed among BMI groups in patients who underwent lobectomy, with underweight and class II obese patients being at the highest risk ( P =0.006). However, the actual number of complications was relatively small and similar among the groups. In patients who underwent total thyroidectomy and isthmectomy, BMI was not correlated with postoperative complications, including hypocalcemia, recurrent laryngeal nerve palsy, postoperative bleeding, and chyle leakage. CONCLUSION: Body habitus was not significantly associated with operative time and postoperative complications in patients undergoing BABA robotic thyroidectomy, indicating that this approach is safe and feasible in obese patients.

The Fate of Sensation in Noninnervated Perforator Free Flaps in the Lower Extremity.

BACKGROUND: The recovery of sensation for noninnervated perforator flaps is not well understood. This prospective study aims to evaluate the quality, tendency, and related factors for recovery of sensation. METHODS: A total of 187 patients over a 6-year period were evaluated at intervals of 3, 6, 12, and +24 months for demographic data and sensory tests [Semmes-Weinstein (SW) monofilament test, static two-point discrimination, temperature, and pain] on peripheral and central regions of the flap. Further detailed assessment using the SW monofilament test was made according to flap thickness, size, type, and recipient sites. Factors correlated to poor recovery were evaluated. RESULTS: Among the flaps tested, the 5.07 SW monofilament test revealed that the peripheral flap sensory recovery was achieved in 72% at +24 months with a significantly increasing linear trend ( P < 0.001). However, the central recovery was noted in only 26% to 28%. The two-point discrimination was achieved in 21% without a significant trend, whereas temperature and pain showed significant improvement, achieving 49% and 64% on the peripheral region and 22% and 31% for the central region, respectively. The flap thickness, size, type, and recipient sites did not exert significance. Only smoking was a significant factor, with 13 times higher odds of hindering sensory recovery. CONCLUSIONS: The SW monofilament test, temperature, and pain sensation on the periphery of the flap showed increasing trend of recovery over the +24 months. Among the various factors, only smoking attenuated recovery. Understanding the fate of sensory recovery in noninnervated perforator flaps will allow the surgeons to further customize the reconstruction based on the defect and maximize efficiency. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Use of Recanalized Vessels for Diabetic Foot Reconstruction: Pushing the Boundaries of Reconstruction in a Vasculopathic Lower Extremity.

BACKGROUND: Free flap after lower extremity revascularization may enable limb salvage in defects after critical limb ischemia. This study examined the outcomes of reconstruction of ischemic diabetic foot according to the severity of the vessel occlusion and assessed whether recanalized vessels may serve as a reliable recipient vessel. METHODS: A total of 62 patients who underwent diabetic foot reconstruction with free flaps after successful percutaneous transluminal angioplasty (PTA) from February of 2010 to February of 2016 were identified and divided into three groups: group 1, nonoccluded vessels as recipient ( n = 11); group 2, recanalized artery after PTA for partially occluded artery ( n = 30); and group 3, recanalized artery after PTA for completely occluded artery ( n = 21). RESULTS: Flap survival was statistically higher in group 2 (90%) compared with group 3 (67%) ( P < 0.05). Subsequent major amputation was significantly lower in groups 1 and 2 [0/7 and 1/30 (3.3%)] compared with group 3 [5/21 (23.8%)] ( P < 0.05). The patient survival and limb salvage rate was 90.9% at 1 and 3 years in group 1, 89.8% at 1 year and 86.3% at 3 and 5 years in group 2, and 76.2% at 1, 3, and 5 years in group 3. This difference was not statistically significant ( P = 0.485). CONCLUSIONS: The use of recanalized vessels after PTA can be safe for partially occluded arteries but requires caution for completely occluded arteries. Using completely occluded vessels after PTA can be attempted when other options are not available and achieves a 76% chance of limb salvage. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Ultrathin Anterolateral Thigh Free Flap: An Adipocutaneous Flap with the Most Superficial Elevation Plane.

BACKGROUND: Although many efforts have been made to create thinner anterolateral thigh (ALT) flaps, their thickness varies among patients, and the flap may be still too thick to match shallow defects. The authors successfully harvested an ALT flap through the most superficial elevation plane, the superficial fat layer, which was useful to match the shallow defects. METHODS: All patients who underwent ALT free flap reconstruction for upper and lower distal extremity defects were divided retrospectively into groups by ALT flap elevation plane: thin, above the deep fascia; superthin, at the superficial fascia; and ultrathin, through the superficial fat. Preoperative computed tomographic angiography and duplex ultrasonography planning were used for all patients. Anatomical characteristics of donor subcutaneous tissue and surgical details, including flap thickness, flap size, and incidence of flap necrosis were compared among the groups and between sexes. RESULTS: The average deep and superficial fascial depths were 16.7 and 10.8 mm, 12.5 and 8.2 mm, and 9.1 and 5.6 mm ( P < 0.05), and the average flap thickness was 5.8 mm, 7.9 mm, and 7.8 mm ( P = 0.29) in the ultrathin, superthin, and thin ALT groups, respectively. No significant intergroup differences existed in flap size or complications. The deep and superficial fascia were located significantly deeper in female patients (9.4 and 6.0 mm in male patients and 14.9 and 9.6 mm in female patients, respectively). CONCLUSIONS: With precise preoperative planning, the most superficially elevated, ultrathin ALT flap can achieve optimal reconstructions of thin body areas. Female patients with thicker thighs and patients with a high body mass index would benefit from this flap. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Maximizing the Versatility of Thin Flap from the Groin Area as a Workhorse Flap: The Selective Use of Superficial Circumflex Iliac Artery Perforator (SCIP) Free Flap and Superficial Inferior Epigastric Artery (SIEA) Free Flap with Precise Preoperative Planning.

BACKGROUND: This study aimed to evaluate the usefulness of the selective use of the superficial circumflex iliac artery perforator (SCIP) and the superficial inferior epigastric artery (SIEA) flap as a workhorse flap from the groin area with precise preoperative surgical planning. METHODS: A total of 79 free flap reconstructions were performed in the study period; 35 SCIP free flaps and 19 SIEA free flaps were performed in the study period. Detailed preoperative surgical planning was performed using computed tomography (CT) angiography and color Doppler ultrasound. Detailed anatomical information of the flaps and reconstructive outcomes were evaluated. RESULTS: Flap characteristics between SCIP free flaps and SIEA free flaps were similar. The average transverse distance of the perforator from anterior superior iliac spine was 15.91 cm in SCIP free flaps and 43.15 cm in SIEA free flaps. The overall flap success rate was 96.4%. Majority of the patients achieved satisfactory contour without debulking surgery. Donor site morbidity was minimal with one case of wound dehiscence. CONCLUSION: The selective use of the SCIP and SIEA free flap in groin area is a safe and useful technique. The surgical outcomes were reliable and similar between the SCIP and SIEA free flaps. Preoperative vascular planning using CT angiography and color Doppler ultrasound is essential for selecting the proper flap.

Evaluation of wound healing effects of micronized acellular dermal matrix in combination with negative pressure wound therapy: In vivo study.

Acellular dermal matrix (ADM) grafts can provide coverage for full-thickness skin defects and substitute for dermal defects. We tested the effectiveness of micronized ADM (mADM) as a dressing material, combined with negative pressure wound therapy (NPWT), for managing superficial wounds. We compared the wound healing effect of mADM in combination with NPWT with those of gelatin and mADM applied with a foam dressing. These therapeutic materials were applied to 36 cm2 excisional wounds in a porcine full-thickness skin defect model. Wound healing kinetics and new tissue formation were assessed 10 days after the initial treatment by measuring the wound area. Collagen deposition and neovascularization were histologically evaluated. Compared with the other two groups, mADM plus NPWT combination group had a significantly larger wound area at the baseline (P = .0040), but the smallest on the 7th day (P = .0093). In addition, collagen formation and neovascularization were more histologically promoted than in the other two groups. mADM showed better results than the gelatin group but less collagen and revascularization than the combination group, and there was no significant difference in wound area. Our results show that the combination of mADM and NPWT has a synergistic wound healing effect.

Planes for Perforator/Skin Flap Elevation-Definition, Classification, and Techniques.

BACKGROUND: Elevation in different layers achieving thin flaps are becoming relatively common practice for perforator flaps. Although postreconstruction debulking achieves pleasing aesthetic results and is widely practiced, customized approach during elevation to achieve the ideal thickness will increase efficiency while achieving the best possible aesthetic outcome. Multiple planes for elevation have been reported along with different techniques but it is quite confusing and may lack correspondence to the innate anatomy of the skin and subcutaneous tissue. METHODS: This article reviews the different planes of elevation and aims to clarify the definition and classification in accordance to anatomy and present the pros and cons of elevation based on the different layers and provide technical tips for elevation. RESULTS: Five different planes of elevation for perforator flaps are identified: subfascial, suprafacial, superthin, ultrathin, and subdermal (pure skin) layers based on experience, literature, and anatomy. CONCLUSION: These planes all have their unique properties and challenges. Understanding the benefits and limits along with the technical aspect will allow the surgeon to better apply the perforator flaps.

Comparative Analysis between Side-to-End and End-to-End Lymphaticovenous Anastomosis for Secondary Lower Limb Lymphedema.

BACKGROUND: The purpose of this retrospective study was to describe, evaluate, and compare the outcome between end-to-end and side-to-end lymphaticovenous anastomoses for all stages of lymphedema. METHODS: A total of 123 patients were divided into the end-to-end ( n = 63) or the side-to-end ( n = 60) group. The demographics and intraoperative and postoperative findings were evaluated. In addition, subcategory evaluation was performed for early- and advanced-phase lymphedema. RESULTS: The demographic findings were insignificant. The intraoperative findings showed a significantly higher number of lymphaticovenous anastomoses performed for the end-to-end group (4.1 ± 1.7) over the side-to-end group (3.2 ± 1.2) ( p < 0.001), whereas the number of different lymphatic vessels used per patient was not significant (3.4 ± 1.4 versus 3.2 ± 1.2; p = 0.386). The diameter of the lymphatic vessels was not significant (0.43 ± 0.06 mm versus 0.45 ± 0.09 mm; p = 0.136). Although both groups showed significant postoperative volume reduction, the side-to-end group had a significantly better reduction in all time intervals ( p < 0.03) and longitudinal outcome ( p = 0.004). However, the subcategory evaluation for early-phase patients showed no difference between the two groups, but a significantly better volume reduction ratio was noted for the side-to-end group at all time intervals ( p < 0.025) in addition to overall longitudinal outcome ( p = 0.004) in advanced lymphedema patients. CONCLUSIONS: This is the first study to report the efficacy of end-to-end versus side-to-end lymphaticovenous anastomosis in different phases of lymphedema. Although both end-to-end and side-to-end lymphaticovenous anastomoses are significantly effective in volume reduction, there was a significantly better reduction for the side-to-end group in advanced-phase lymphedema patients with stage II late and stage III disease, whereas no difference was noted for early-phase lymphedema patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Risk Factors for Partial Flap Loss in a Free Flap: A 12-Year Retrospective Study of Anterolateral Thigh Free Flaps in 303 Lower Extremity Cases.

BACKGROUND: Despite remarkable improvements in free flap procedures, partial flap losses in perforator flaps still occur. This study aimed to analyze partial necrosis cases that underwent reconstruction of the lower extremities using anterolateral thigh free flaps and to identify risk factors causing the occurrence of partial necrosis. METHODS: From January of 2005 to February of 2017, 303 anterolateral thigh free flaps were analyzed retrospectively. After collecting patient data, receiver operating characteristic curve analysis was conducted to find the critical distance between the perforator and the flap margin that distinguishes partial necrosis. Also, the rate of partial losses was calculated for each section after dividing the distance from the perforator to the flap margin into 1-cm sections. Lastly, logistic regression analyses were performed to identify the risk factors. RESULTS: Forty-three cases had partial flap loss (14.19 percent). Flaps with supradeep fat layer elevation showed the highest rate of partial necrosis (25.53 percent), with statistical significance ( p = 0.0001). In receiver operating characteristic curve analysis, the cutoff distance was 10.25 cm. In addition, flap tissues 8 cm away from the perforator have a 10.3 percent chance of necrosis, whereas those 12 cm away from the perforator have a 22.9 percent chance. Lastly, supradeep fat layer elevation (OR, 3.952) and large flap size (OR, 1.041) were risk factors for partial flap necrosis on multivariate analysis. CONCLUSIONS: The distance from the perforator to the flap margin, the flap elevation layer, and the flap size affected the occurrence of partial necrosis. Taking these into consideration, anterolateral thigh free flaps of appropriate size and thickness should be harvested. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.