Multi-modal co-learning with attention mechanism for head and neck tumor segmentation on 18FDG PET-CT.

PURPOSE: Effective radiation therapy requires accurate segmentation of head and neck cancer, one of the most common types of cancer. With the advancement of deep learning, people have come up with various methods that use positron emission tomography-computed tomography to get complementary information. However, these approaches are computationally expensive because of the separation of feature extraction and fusion functions and do not make use of the high sensitivity of PET. We propose a new deep learning-based approach to alleviate these challenges. METHODS: We proposed a tumor region attention module that fully exploits the high sensitivity of PET and designed a network that learns the correlation between the PET and CT features using squeeze-and-excitation normalization (SE Norm) without separating the feature extraction and fusion functions. In addition, we introduce multi-scale context fusion, which exploits contextual information from different scales. RESULTS: The HECKTOR challenge 2021 dataset was used for training and testing. The proposed model outperformed the state-of-the-art models for medical image segmentation; in particular, the dice similarity coefficient increased by 8.78% compared to U-net. CONCLUSION: The proposed network segmented the complex shape of the tumor better than the state-of-the-art medical image segmentation methods, accurately distinguishing between tumor and non-tumor regions.

Chip collection of hepatocellular carcinoma based on O2 heterogeneity from patient tissue.

Hepatocellular carcinoma frequently recurs after surgery, necessitating personalized clinical approaches based on tumor avatar models. However, location-dependent oxygen concentrations resulting from the dual hepatic vascular supply drive the inherent heterogeneity of the tumor microenvironment, which presents challenges in developing an avatar model. In this study, tissue samples from 12 patients with hepatocellular carcinoma are cultured directly on a chip and separated based on preference of oxygen concentration. Establishing a dual gradient system with drug perfusion perpendicular to the oxygen gradient enables the simultaneous separation of cells and evaluation of drug responsiveness. The results are further cross-validated by implanting the chips into mice at various oxygen levels using a patient-derived xenograft model. Hepatocellular carcinoma cells exposed to hypoxia exhibit invasive and recurrent characteristics that mirror clinical outcomes. This chip provides valuable insights into treatment prognosis by identifying the dominant hepatocellular carcinoma type in each patient, potentially guiding personalized therapeutic interventions.

Sex disparities in physical activity domains and hypertension prevalence.

BACKGROUND: This study aimed to examine the associations of leisure time physical activity (LTPA) and occupational physical activity (OPA) with the prevalence of hypertension, while exploring the sex disparities in these associations. METHODS: A cross-sectional study was conducted using data from the Korea National Health and Nutrition Examination Survey between 2014 and 2019 (n = 26,534). Hypertension was defined as the use of antihypertensive drugs or systolic and diastolic blood pressure ≥ 140/90 mm Hg. Self-reported physical activity (PA), assessed by the global PA questionnaire, was categorized into three domains: total PA, LTPA and OPA. Each PA domain was classified based on METs-min/wk and intensity. RESULTS: In a multivariable adjusted model, the odds ratio (OR) with 95% confidence intervals (CIs) for the prevalence of hypertension in the active versus inactive group, based on METs, was 0.92 (95% CI 0.85-0.99) for total PA, 0.90 (95% CI 0.83-0.98) for LTPA and 1.21 (95% CI 1.05-1.38) for OPA. Compared to the inactive group, moderate to vigorous intensity was associated with a lower odds of hypertension for total PA and LTPA (total PA: OR 0.95, 95% CI 0.89-1.00 and LTPA: OR 0.92, 95% CI 0.86-0.98), but a higher odd for OPA (OR 1.17, 95% CI 1.05-1.30). Subgroup analyses showed significant evidence of effect modification by sex on the associations of total PA and LTPA (METs and intensity) with hypertension prevalence (p-values for interaction < 0.01); the associations were generally stronger for women. OPA was associated with a higher prevalence of hypertension in women, but not in men (p-value for interaction > 0.05). CONCLUSIONS: Higher levels of total PA and LTPA were associated with lower prevalence of hypertension in both men and women, with slightly stronger associations for women. However, higher OPA was associated with a higher prevalence of hypertension in women. These findings support the PA health paradox hypothesis and highlight the sex disparities in the association between OPA and hypertension prevalence.

The current use of tissue expanders in breast reconstruction: device design, features, and technical considerations.

INTRODUCTION: The use of tissue expanders (TE) in post-mastectomy breast reconstruction is a widely accepted practice, especially in patients desiring implant-based breast reconstruction. It has become the standard of care to perform a two-staged breast reconstruction using tissue expanders for the past 50 years due to its reliability, safety, cost-effectiveness, and versatility. Due to its popularity, there are numerous types and features of breast tissue expanders and various surgical approaches available for plastic surgeons. AREAS COVERED: In this article, we will review the role of tissue expanders in breast reconstruction, the types and features of breast tissue expanders, and technical considerations. EXPERT OPINION: The use of tissue expanders in breast reconstruction offers significant advantages of preserving the breast skin envelope and reestablishing the breast mound. With evolving approaches to breast reconstruction, tissue expander design, and application underwent several refinements and modifications. Due to these advances, studies on its long-term efficacy and safety profile typically fall behind and more studies with higher levels of evidence are needed to better evaluate the efficacy and safety profile of tissue expanders. With increased understanding, reconstructive surgeons can minimize complications and maximize reconstructive, aesthetic outcomes with high patient satisfaction.

Building Complex Autologous Breast Reconstruction Program: A Preliminary Experience.

Autologous breast reconstruction is an increasingly popular method of reconstruction for breast cancer survivors. While deep inferior epigastric perforator (DIEP) flaps are the gold standard, not all patients are ideal candidates for DIEP flaps due to low BMI, body habitus, or previous abdominal surgery. In these patients, complex autologous breast reconstruction can be performed, but there is a limited number of programs around the world due to high technical demand. Given the increased demand and need for complex autologous flaps, it is critical to build programs to increase patient access and teach future microsurgeons. In this paper, we discuss the steps, pearls, and preliminary experience of building a complex autologous breast reconstruction program in a tertiary academic center. We performed a retrospective chart review of patients who underwent starting the year prior to the creation of our program. Since the start of our program, a total of 74 breast mounds have been reconstructed in 46 patients using 87 flaps. Over 23 months, there was a decrease in median surgical time for bilateral reconstruction by 124 min (p = 0.03), an increase in the number of co-surgeon cases by 66% (p < 0.01), and an increase in the number of complex autologous breast reconstruction by 42% (p < 0.01). Our study shows that a complex autologous breast reconstruction program can be successfully established using a multi-phase approach, including the development of a robust co-surgeon model. In addition, we found that a dedicated program leads to increased patient access, decreased operative time, and enhancement of trainee education.

The Role of Reconstruction on Desmoid Tumor Recurrence: A Systematic Review and Technical Considerations.

BACKGROUND: Desmoid tumors occur throughout the body, presenting as aggressive, locally invasive lesions that can impede quality of life. Many controversies remain regarding the optimal surgical treatment of desmoid. This article presents a systematic review and meta-analysis on surgical management, focusing on risk of recurrence and the utility of reconstruction within this unique patient population. METHODS: A systematic review was conducted to search for articles. The clinical course of patients diagnosed with desmoid tumors and treated by our institution's multidisciplinary team was retrospectively reviewed over a 13-year period. Meta-analysis study findings were compared with our cohort. RESULTS: From the systematic review, 10 studies with level of evidence III were found, which resulted in 981 patients. Twenty patients from our institution met the inclusion criteria for our study. In both our study cohort and the pooled results, recurrence was significantly higher in patients with positive microscopic margin after resection. In our study cohort, patients with recurrence had higher rates of positive margins compared with those without recurrence (83.3% vs 7.1%, P = 0.004), whereas the pooled study showed a difference of margin positivity of 50% vs 40% ( P = 0.01). No patients who underwent reconstruction in our study cohort had a recurrence during the study period. CONCLUSION: In both our cohort and pooled results, recurrence was significantly higher in patients with positive margins after initial resection. Reconstruction was not found to be a risk factor for recurrence. Reconstruction following desmoid tumor resection should be considered a viable option if a large and aggressive resection is required to obtain negative margins.

Virtual Surgical Planning in Free Tissue Transfer for Orbito-Maxillary Reconstruction.

Since its introduction, virtual surgical planning (VSP) has been rapidly adopted as a part of reconstructive surgeon's armamentarium. VSP allows reconstructive surgeons to simulate resection, plan osteotomies, and design custom plates. These unique advantages have been especially beneficial for head and neck reconstructive surgeons as there is small room for error and high technical demand in head and neck reconstruction. Despite its popularity, most surgeons have limited experience in using VSP for orbito-maxillary reconstruction as tumors that involve the midface are relatively rare compared with other head and neck oncologic defects. In our institution, we routinely use VSP for orbito-maxillary reconstruction using free fibula flap to provide support for orbit, to restore normal dental occlusion, and to restore midface projection. In this chapter, we will discuss the role of virtual surgical planning and our algorithmic approach of performing orbito-maxillary reconstruction using free tissue transfer.

A Retrospective Case Series on Free Flap Reconstruction for Ischemic Diabetic Foot: The Nutrient Flap Further Explained.

BACKGROUND: This retrospective case series compares the outcomes and postoperative oxygen levels in patients who underwent free flap versus primary closure/local flap reconstruction for ischemic diabetic foot wounds to determine the influence of free flap on the surrounding ischemic tissues. The authors hypothesized that the free flap would benefit the surrounding ischemic tissue as a nutrient flap by increasing the tissue oxygen content. METHODS: The patients were divided into two groups: group 1 underwent free flap reconstruction, and group 2 underwent partial foot amputation with primary closure/local flap. Patient demographics, endovascular intervention, surgical outcome, postreconstruction intervention, and prereconstruction and postreconstruction transcutaneous oximetry were analyzed. RESULTS: Among 54 patients, 36 were in group 1 and 18 were in group 2. There were no differences in patient demographics between the two groups. All patients had successful angioplasty. Statistical significance was noted in postreconstruction intervention in which group 2 required 2.8 ± 2.9 débridements (versus 1.2 ± 2.5 for group 1) and seven of 18 below-knee amputations (versus three of 36 for group 1) (p < 0.05). Transcutaneous partial pressure of oxygen levels were significantly higher in group 1 at 6 months after reconstruction (61.6 ± 7.5 versus 32.6 ± 5.8 mmHg) (p < 0.01). CONCLUSION: This study shows that the role of the free flap in ischemic diabetic limb may expand beyond that of providing coverage over the vital structures, and it supports the use of the free flap as a nutrient to increase oxygen content in the ischemic diabetic foot. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Harvesting Composite Arterial and Vein Grafts from Deep Inferior Epigastric Artery and Vein: A Safe Five-Step Method of Preparation.

BACKGROUND: As the use of stacked flaps and options for autologous breast reconstruction increase, the level of complexity in autologous breast reconstruction has risen. Frequently, these reconstruction types present technical challenges such as vessel mismatches and short pedicle length. In this study, the authors introduce their five steps of harvesting composite deep inferior epigastric artery (DIEA) and deep inferior epigastric vein (DIEV) grafts to overcome such challenges. METHODS: The authors performed a retrospective review of patients who underwent microvascular reconstruction using DIEA/DIEV grafts from 2012 to 2020. The grafts were harvested using the five steps, as follows: step 1, a transverse, paramedian skin incision was made at the level of suprapubic crease; step 2, an oblique fasciotomy was made on the lateral rectus border; step 3, DIEA/DIEV vessels were identified and exposed past the confluence of two venae comitantes; step 4, DIEA/DIEV grafts were harvested while sparing motor nerves; and step 5, fascial closure was performed. RESULTS: A total of 40 DIEA/DIEV grafts were used in 25 patients (lumbar artery perforator flaps, n = 25; lateral thigh flaps, n = 1; superficial inferior epigastric artery flaps, n = 12; and flap salvage, n = 2) for breast reconstruction. The average time of harvest was 28 minutes, and there were two flap losses. CONCLUSIONS: In the authors' experience, DIEA/DIEV grafts can be safely harvested and used in flaps with short pedicles and small vessel size. Although the authors' experience was limited to breast reconstruction, the DIEA/DIEV grafts can be used for other types of reconstruction, especially for head and neck reconstruction.

Utility of ERAS Pathway in Nonabdominal-Based Microsurgical Breast Reconstruction: Efficacy in PAP Flap Reconstruction?

BACKGROUND: Enhanced recovery after surgery (ERAS) protocols are effective in decreasing hospital length of stay and inpatient opioid consumption. Implementation of these protocols in abdominally based breast reconstruction has been successful. When a patient is a poor candidate for abdominally based flaps a popular secondary option is the profunda artery perforator (PAP) flap. We present our experience with implementation of our ERAS protocol in patients treated with PAP flaps for breast reconstruction. METHODS: Retrospective review of patients treated with autologous breast reconstruction using PAP flaps before and after ERAS implementation were performed. Patient characteristics, postoperative oral morphine equivalents (OMEs), and flap data were collected. RESULTS: A total of 87 patients were included in this study (58 patients in pre-ERAS and 29 patients in ERAS group). There was no statistical difference in patient age, comorbidities, smoking, and radiation between two groups. The ERAS group had statistically lower hospital length of stay (2.6 vs. 3.8 days), procedure time (315 vs. 433 minutes), postoperative day 0 (54.8 vs. 96.3), postoperative day 1 (29.9 vs. 57.7), and total opioid consumption (103.7 vs. 192.1). There was no statistical difference in average pain scores between two groups. Multivariate analysis revealed that procedure time significantly increased the amount of opioid consumption while ERAS implementation significantly reduced LOS and opioid consumption. CONCLUSION: Use of an ERAS protocol in PAP flap breast reconstruction has not been previously studied. Our work shows that ERAS implementation in PAP flap breast reconstruction significantly reduces inpatient opioid use and length of hospital stay.

Microtubule Integrity Is Associated with the Functional Activity of Mitochondria in HEK293.

Mitochondria move along the microtubule network and produce bioenergy in the cell. However, there is no report of a relationship between bioenergetic activity of mitochondria and microtubule stability in mammalian cells. This study aimed to investigate this relationship. We treated HEK293 cells with microtubule stabilizers (Taxol and Epothilone D) or a microtubule disturber (vinorelbine), and performed live-cell imaging to determine whether mitochondrial morphology and bioenergetic activity depend on the microtubule status. Treatment with microtubule stabilizers enhanced the staining intensity of microtubules, significantly increased ATP production and the spare respiratory capacity, dramatically increased mitochondrial fusion, and promoted dynamic movement of mitochondria. By contrast, bioenergetic activity of mitochondria was significantly decreased in cells treated with the microtubule disturber. Our data suggest that microtubule stability promotes mitochondrial functional activity. In conclusion, a microtubule stabilizer can possibly recover mitochondrial functional activity in cells with unstable microtubules.

Comparison of the Incidence of Postoperative Hypothyroidism in Patients Undergoing Conventional Thyroid Lobectomy and Pyramid- and Isthmus-Preserving Lobectomy.

Hypothyroidism is a recognized sequela of conventional thyroid lobectomy. However, there have been no studies on the incidence of hypothyroidism following the preservation of the isthmus and pyramid during lobectomy. Therefore, in the present study, we compared the incidence of hypothyroidism following conventional lobectomy and lobectomy during which the isthmus and pyramidal lobe were preserved. Data for a total of 65 patients collected between September 2018 and April 2019 were reviewed retrospectively. Circulating thyroid-stimulating hormone (TSH) concentration was measured before and after surgery in a group who underwent conventional thyroid lobectomy (n = 29) and in a group in which the isthmus and pyramid were preserved (n = 36). We found no significant difference in TSH concentration between the two groups before surgery, or 3 months or 1 year after surgery. Thus, there might be no difference in the incidence of postoperative hypothyroidism between patients who undergo conventional thyroid lobectomy and those in which the isthmus and pyramid are preserved.

MIT-001 Restores Human Placenta-Derived Mesenchymal Stem Cells by Enhancing Mitochondrial Quiescence and Cytoskeletal Organization.

Inflammation is a major cause of several chronic diseases and is reported to be recovered by the immuno-modulation of mesenchymal stem cells (MSCs). While most studies have focussed on the anti-inflammatory roles of MSCs in stem cell therapy, the impaired features of MSCs, such as the loss of homeostasis by systemic aging or pathologic conditions, remain incompletely understood. In this study, we investigated whether the altered phenotypes of human placenta-derived MSCs (hPD-MSCs) exposed to inflammatory cytokines, including TNF-α and IFN-γ, could be protected by MIT-001, a small anti-inflammatory and anti-necrotic molecule. MIT-001 promoted the spindle-like shape and cytoskeletal organization extending across the long cell axis, whereas hPD-MSCs exposed to TNF-α/IFN-γ exhibited increased morphological heterogeneity with an abnormal cell shape and cytoskeletal disorganization. Importantly, MIT-001 improved mitochondrial distribution across the cytoplasm. MIT-001 significantly reduced basal respiration, ATP production, and cellular ROS levels and augmented the spare respiratory capacity compared to TNF-α/IFN-γ-exposed hPD-MSCs, indicating enhanced mitochondrial quiescence and homeostasis. In conclusion, while TNF-α/IFN-γ-exposed MSCs lost homeostasis and mitochondrial quiescence by becoming over-activated in response to inflammatory cytokines, MIT-001 was able to rescue mitochondrial features and cellular phenotypes. Therefore, MIT-001 has therapeutic potential for clinical applications to treat mitochondrion-related inflammatory diseases.

Level of Evidence on Platelet-rich Plasma in Plastic Surgery.

BACKGROUND: Despite the increased popularity of platelet-rich plasma (PRP) in plastic surgery, there is no detailed analysis on the level of evidence on PRP use in plastic surgery. As the number of applications of PRP in plastic surgery increases, it is important for plastic surgeons to understand the scientific and validated evidence behind its use. Therefore, we performed a literature review to identify current level of evidence on platelet-rich plasma in plastic surgery. METHODS: We performed a computerized search of platelet-rich plasma in plastic surgery using the MEDLINE, Cochran Library, and EMBASE databases. Data regarding the type of study, PRP application, and outcomes were collected. Then, the level of evidence was assigned using the American Society of Plastic Surgeons Level of Evidence Rating. RESULTS: Our search identified 105 articles, and about 78.1% of studies were lower-quality studies: 37 level-III articles (35.2%), 32 level-IV articles (30.5%), and 13 level-V articles (12.4%). There were only 6 level-I articles and 17 level-II studies. Level-I studies were on facial rejuvenation using a laser, carpal tunnel release, cleft lip repair, trauma wounds, breast reconstruction using latissimus dorsi, and hair regrowth. CONCLUSIONS: Our review of the literature shows that the level of evidence on PRP use in plastic surgery is low (21.9%). Nevertheless, we believe level-III to level-V studies are still valuable, as performing high-level quality studies in plastic surgery is difficult due to variability in surgical techniques, experiences, and materials.

The emergence of virtual education during the COVID-19 pandemic: The past, present, and future of the plastic surgery education.

BACKGROUND: Since the global outbreak of coronavirus disease-2019 (COVID-19), plastic surgeons were forced to transition from traditional didactics to virtual lectures to practice "social distancing." As this method of education continues to be widely used, understanding the current trend of its usage is critical. In this study, we performed a survey study of virtual lecture attendees and presenters to determine current usage and general consensus on virtual lectures in plastic surgery education. METHODS: An electronic survey was sent to attendees and presenters of virtual lectures using Google Forms. Demographic data, webinar usage patterns, and views on virtual lectures were collected. RESULTS: A total of 417 surveys were received. Prior to the COVID-19 era, 39.1percent of attendees did not use virtual lectures and 45.6percent of presenters did not give webinars at all. Both groups reported that the lack of opportunities and need were the most common cause of no use of lectures or webinars. After the outbreak, 35.4percent of attendees now use virtual lectures daily and 51.4percent of presenters give lectures weekly. Over 90percent of the study population reported a positive experience with the virtual lectures due to increased interaction, convenience, outreach, and usability. Finally, over 75percent stated that virtual lectures might replace classroom lectures in the future. CONCLUSION: Our study shows that a majority of plastic surgeons have begun to use and give virtual lectures daily after the COVID-19 outbreak. Virtual education is a powerful and versatile tool that has great potentials, and it may continue to serve as a part of surgical training in the future.

The mitochondrial-derived peptide MOTS-c promotes homeostasis in aged human placenta-derived mesenchymal stem cells in vitro.

Mesenchymal stem cells (MSCs) are multipotent cells with critical roles in homeostasis and regeneration. MSCs undergo aging in response to various stresses, and this causes many diseases including degenerative disorders. Thus, regulation of aging factors is crucial for healthy aging. Mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) was recently reported to regulate metabolic homeostasis. Here, we investigated the restorative effects of MOTS-c on aged human placenta-derived MSCs (hPD-MSCs). MOTS-c promoted the morphology of old hPD-MSCs. MOTS-c significantly activated AMP-activated protein kinase, which is the main target pathway of MOTS-c, and inhibited its antagonistic effector mTORC1. MOTS-c considerably enhanced mitochondrial homeostasis by decreasing oxygen consumption and reactive oxygen species production. The mitochondrial state of MOTS-c-treated old hPD-MSCs was more similar to that of young hPD-MSCs than the mitochondrial state of non-treated old hPD-MSCs. MOTS-c also decreased lipid synthesis. In conclusion, we demonstrated that MOTS-c promotes homeostasis in aged hPD-MSCs.

Lymph Node to Vein Anastomosis (LNVA) for lower extremity lymphedema.

The microsurgical options for lower limb lymphedema is a challenge. In search to improve the overall result, we hypothesized it would be beneficial to add the functioning lymph nodes to vein anastomosis (LNVA) in addition to lymphovenous anastomosis (LVA). This is a retrospective study of 160 unilateral stage II & III lower extremity lymphedema comparing the outcome between the LNVA + LVA group and the LVA only group from May 2013 to June 2018. MRI was used to identify the functioning lymph nodes. Patient outcome, including lower extremity circumference, body weight, bio impedance test, and other data were analyzed to evaluate whether lymph nodes to vein anastomosis (LNVA) improved outcome. The LNVA + LVA group showed significantly better results for circumference reduction rate, body weight reduction rate, and extracellular fluid reduction rate of the affected limb as compared to the LVA only group for both stage II and III lymphedema. The MRI imaging revealed that 9 cases had no identifiable lymph nodes of the affected limb and 54 cases with a nonfunctioning lymph node upon exploration despite positive imaging. Correlation showed the lymph node size needed to be at least 8 mm in the MRI to be functional. The LNVA + LVA approach for lymphedema has the benefit of better reduction as compared to LVA alone in the lower limb as well as the suprapubic region. Preoperative MRI will help to identify the functioning lymph node by increasing the overall probability of positive outcome.

Association between Periodontal Health and Stroke: Results from the 2013-2015 Korea National Health and Nutrition Examination Survey (KNHANES).

BACKGROUND/PURPOSE: As the population ages, the prevalence of stroke increases, and as such there has been increasing interest in the risk factors associated with stroke. Although an association between periodontitis and stroke has been suggested, there has been no study of this association among the Korean population. Therefore, we investigated the association between periodontal health and stroke among Korean adults. MATERIALS AND METHODS: A total of 9497 adults aged ≥40 years representing the Korean population were included in this cross-sectional study from the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2013-2015). Periodontitis was diagnosed by dentists based on the Community Periodontal Index (CPI). Also, participants filled out a questionnaire regarding their experience of doctor-diagnosed stroke. Hypertension, diabetes, body mass index (BMI), and oral hygiene behavior covariates were adjusted in logistic regression analysis. RESULTS: The mean age of the study population was 55.71 ±â€¯0.17 years and 52.7% of them were female. Also, 248 people had a history of having a stroke. Results of the logistic regression analysis after adjusting for age and sex showed a significant relationship between oral health behavior, periodontal health, and stroke even after adjusting for age, sex, education, household income, national health insurance, employment status, alcohol, smoking, diabetes, hypertension, BMI, and oral health behaviors (odds ratio [OR], 1.71; 95% confidence interval [CI] = 1.03-2.85). CONCLUSION: Our findings suggest that periodontitis is associated with stroke in Korean adults.

Changing the Paradigm: Lymphovenous Anastomosis in Advanced Stage Lower Extremity Lymphedema.

BACKGROUND: Traditionally, lymphovenous anastomosis is not routinely performed in patients with advanced stage lymphedema because of difficulty with identifying functioning lymphatics. This study presents the use of duplex ultrasound and magnetic resonance lymphangiography to identify functional lymphatics and reports the clinical outcome of lymphovenous anastomosis in advanced stage lower extremity lymphedema patients. METHODS: This was a retrospective study of 42 patients (50 lower limbs) with advanced lymphedema (late stage 2 or 3) that underwent functional lymphovenous anastomoses. Functional lymphatic vessels were identified preoperatively using magnetic resonance lymphangiography and duplex ultrasound. RESULTS: An average of 4.64 lymphovenous anastomoses were performed per limb using the lymphatics located in the deep fat underneath the superficial fascia. The average diameter of lymphatic vessels was 0.61 mm (range, 0.35 to 1 mm). The average limb volume was reduced 14.0 percent postoperatively, followed by 15.2 percent after 3 months, and 15.5 percent after 6 months and 1 year (p < 0.001). For patients with unilateral lymphedema, 32.4 percent had less than 10 percent volume excess compared to the contralateral side postoperatively, whereas 20.5 percent had more than 20 percent volume excess. The incidence of cellulitis decreased from 0.84 per year to 0.07 per year after surgery (p < 0.001). CONCLUSION: This study shows that functioning lymphatic vessels can be identified preoperatively using ultrasound and magnetic resonance lymphangiography; thus, lymphovenous anastomoses can effectively reduce the volume of the limb and improve subjective symptoms in patients with advanced stage lymphedema of the lower extremity. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.