Large Scars Research Articles

Abstract 125: Tropical hypopitutarism – Single centre experience

Background: Etiology of hypopituitarism differs in tropical countries compared to the West and includes pituitary abscess, snake bite, HIV infection, Sheehan syndrome, road traffic accidents, iron overload states etc.Aims and Objectives: The present case series highlights the spectrum of hypopituitarism in tropical countries.Case Details: C1: 23 y/o female presented with loss of consciousness, unrecordable BP and hypoglycemia. H/O spontaneous pre term delivery at home with significant PPH with lactational failure. C2: 21 y/o male came with c/o poor height and weight gain and poor development of secondary sexual characteristics. Examination revealed a large healed scar over foot which developed after snake bite in past. C3: 41 y/o female with h/o recurrent episodes of altered sensorium. H/o PPH, lactational failure, amenorrhea following home delivery. C4: 30 y/o female presented with h/o delivery with PPH, followed by amenorrhea, lactation failure with sparse axillary, pubic hair. MRI pituitary was normal in C1 and showed empty sella for C2, C3 and C4.Conclusion: The etiology and clinical features of hypopituitarism are variable. Awareness and early recognition in these cases is necessary for optimal management of the patient.

Unburnt patches maintain bird abundance and species richness following large wildfires in an Australian semiarid woodland ecosystem

Large wildfires can cause widespread disruption to ecosystems and animal populations, but patches left unburnt within fire scars may play a key role in the persistence and post-fire recovery of communities, which may depend on habitat characteristics, patch size, or spatial configuration. To test this, we made use of a natural experiment in which a semi-arid landscape was burnt twice in the space of eight years. We surveyed bird assemblages at 130 sites, and tested the relative importance of time since fire, habitat features and landscape configuration of unburnt patches for post-fire species abundance, species richness and phylogenetic diversity. In the first three years after fire, abundance of 4/18 bird species were higher in unburnt patches than the surrounding burnt matrix, and after 8–10 years abundance of three species was still higher in unburnt patches. Short-term post-fire variation in species richness was associated with habitat differences between burnt and unburnt areas, but not with habitat differences among unburnt areas, nor with patch size or spatial configuration. Our results suggest that even small or isolated unburnt patches are important in maintaining bird abundance and species richness, and facilitating recovery of animal populations across large fire scars, especially in the first three years after a major fire event.

The Clinical Evaluation of Minimally Invasive Treatment for Axillary Osmidrosis

Background: Traditional treatment of axillary odour is the surgical removal of skin and subcutaneous tissue along the edge of the axillary hair in a fusiform shape, which requires the restriction of upper limb activity, has large scars and a high recurrence rate. Minimally invasive methods have developed in recent years. The subcutaneous trimming method with small incision reduces the incision compared to traditional incision, but still requires skin incision, which does not achieve true, minimally invasive treatment. Simple negative pressure suction is difficult to destroy the sweat glands and sebaceous glands in the dermis layer. Thus, we hypothesized that combination of three minimally invasive methods might be more effective. Objective: To explore the clinical effect of combined treatment of axillary osmidrosis by three minimally invasive methods of microwave, scraping & suction and scratching. Methods: From October 2015 to October 2020, 80 patients with underarm odor were enrolled and lacal swelling anesthetic was applied. Microwave was used to treat sweat glands and sebaceous glands in the dermis following the pores. The curettage-aspiration was used to scrape and suck the apocrine sweat glands in the subcutaneous fat layer and the junction between the subcutaneous fat and dermis. To achieve the purpose of minimally invasive and thorough treatment of underarm odor, the spoon scraped the remaining sweat gland tissue. Results: Among 80 patients on 160 sides, all cases (100.00%) were cured on 160 sides at 1 month post-operative follow-up, 75 cases (93.75%) were cured on 150 sides, 5 cases (6.25%) on 5 sides were ineffective at 6-month post-operative follow-up, 74 cases (92.50%) were cured on 148 sides, 6 cases (7.50%) on 5 sides were ineffective at 1-year post-operative follow-up. Complications occurred in 5 cases (6.25%) after operation: 2 cases (2.50%) with skin necrosis on 3 sides, 1 case (1.25%) with uneven skin on 2 sides, 1 case (1.25%) with axillary abscess on 2 sides, and 1 case (1.25%) with keloids on 2 sides. Conclusion: The combination of three minimally invasive methods of microwave, scraping & suction and scratching to treat underarm odor is simple operation, has high cure rate, quick postoperative recovery, and few complications. It is an effective method for minimally invasive and thorough treatment of underarm odor in clinic.

Heart Diseases of Uncertain Etiology: Epidemiological Observations Compared with Clinical Experience

Backgrounds and Aims: Simple, long-term epidemiological observations allowed to identify a heterogeneous group of heart diseases manifested only as heart failure, arrhythmia and blocks in the absence of typical coronary syndromes, that we arbitrarily called initially atypical Coronary Heart Disease (CHD) and then Heart Disease of Uncertain Etiology (HDUE) in 12 published investigations. Methods and Results: This group of heart diseases covered about 20% of all CVD mortality and about 10% of all-cause mortality in population cohorts close to extinction and compared with typical CHD was characterized by a strong association with age and the absence or an inverse association with serum cholesterol, dietary habits and physical activity. Moreover, HDUE appeared at an older age and had a higher age at death. Blood pressure and smoking habits (the latter with some uncertainties) were directly associated with the disease. Old pathology findings had already segregated the large myocardial scars due to gross atheroma of coronary arteries from small multiple sclerotic/fibrotic scars that seem independent and unrelated to coronary atheroma. Conclusion: Etiology of HDUE, although probably multiple, is still vague and elusive, and the Literature was little informative about its relative frequency and possible causality. Future investigations might be stimulated by this review. To segregate HDUE from CHD should be important to correctly assess relationships among multiple risk factors and differential or condensed outcomes.

Use of a Mini-subcostal Incision for Living Donor Right Hepatectomy: A Series of 189 Consecutive Cases

Introduction: Living donor hepatectomy is now a well-established surgical procedure. However, a large abdominal incision is still required, which results in a large permanent scar, especially for a right liver graft. Minimally invasive surgery has been widely used for donor operations. This study aimed to determine the safety and feasibility of mini- subcostal incision for living donor right hepatectomy. Methods: We reviewed 1456 patients who underwent living donor right hepatectomy (LDRH) between January 2015 and December 2019 at Asan Medical Center. We performed 1:1 propensity score matching of the LDRH with mini- subcostal incision and the LDRH with conventional incision (J-shape), with 144 patients subsequently included in each group. Results: The total operation time (P =0.018) were longer in the mini- subcostal incision group. None of the donors required intraoperative transfusion or experienced any irreversible disabilities or mortalities. The length of postoperative hospital stay was significantly shorter in the mini- subcostal incision group (P =0.043). The rate of complications in donors was similar between the 2 groups. Graft steatosis were independent predictors of postoperative morbidity after LDRH with mini- subcostal incision on multivariable analysis. Vascular and biliary complication rates in recipients were similar between the 2 groups. Conclusions: LDRH with mini- subcostal incision is feasible when performed at an experienced living donor liver transplantation center. Donor safety is paramount in living donor liver transplantation. In centers with difficulties in performing pure laparoscopic donor right hepatectomy, LDRH with mini-subcostal incision can be an alternative to pure laparoscopic donor right hepatectomy.

A new dromaeosaurid dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and implications for European palaeobiogeography

The Lower Cretaceous of England has produced a diverse assemblage of dinosaurs, including ornithischians, sauropods, and theropods. The origins of this assemblage are poorly understood. Here, we describe a new dromaeosaurid, Vectiraptor greeni gen. et sp. nov., from the Barremian Wessex Formation of the Isle of Wight. The animal is represented by associated dorsal vertebrae and a partial sacrum. Dorsal vertebrae are short, with pleurocoels, camellate pneumatization, stalked parapophyses and enlarged neural canals. Neural spines are tall, with large ligament scars. Sacral centra lack pleurocoels but have large neural canals and foramina suggesting pneumatization. These characters suggest affinities with Dromaeosauridae and specifically the derived, large-bodied Eudromaeosauria. Vectiraptor resembles Early Cretaceous eudromaeosaurs from North America, suggesting a faunal exchange between Europe and North America. The diverse Early Cretaceous dinosaur assemblage found in England and Europe resulted from dispersal from North America, Asia, and West Gondwana, likely involving both land bridges and oceanic dispersal. Europe served as a biotic crossroads in the Early Cretaceous, allowing faunal interchange between landmasses.

Hedgehog Signaling in Papillary Fibroblasts Is Essential for Hair Follicle Regeneration during Wound Healing

Patients suffering from large scars such as burn victims not only encounter aesthetic challenges but also ongoing itching or pain that substantially deteriorates their quality of life. Skin appendages such as hair follicles rarely regenerate within the healing wound. Because they are crucial for skin homeostasis and the lack thereof constitutes one of the main limitations to scarless wound healing, their regeneration represents a major objective for regenerative medicine. Fibroblasts, the main resident cell type of the skin dermis, mediate embryonic hair follicle morphogenesis and are particularly involved in wound healing because they orchestrate extracellular matrix remodeling and collagen deposition in the wound bed. Importantly, dermal fibroblasts originate from two distinct developmental lineages with unique functions that differently mediate the response to epidermal signals such as Hedgehog signaling. In this study, we show that Hedgehog signaling in the reticular fibroblast lineage promotes the initial phase of wound repair, possibly by modulating angiogenesis and fibroblast proliferation, whereas Hedgehog signaling in papillary fibroblasts is essential to induce de novo hair follicle formation within the healing wound.

493 Prognostic value of myocardial scar and chamber enlargement at electroanatomical mapping during catheter ablation in adult congenital heart disease

Abstract Aims Atrial and ventricular tachyarrhythmias are common among patients with adult congenital heart disease (ACHD) and can impair quality of life and prognosis. Catheter ablation is often the main treatment option in this population, despite anatomical hurdles. Substrate mapping findings have not been thoroughly investigated as predictors of arrhythmia recurrence success and cardiovascular clinical outcome after ablation. We sought to determine the prognostic value of myocardial scar and chamber enlargement detected at electroanatomical mapping in ACHD patients undergoing catheter ablation of tachyarrhythmias. Methods and results Consecutive ACHD patients undergoing catheter ablation of atrial and ventricular tachycardias using different electroanatomical mapping systems were retrospectively identified from a hospital-based database. Scar extent detected at the electroanatomical mapping, as well as the total mapped area, was calculated. Arrhythmia recurrence, hospitalization for cardiovascular (CV) reasons, and a combined endpoint (arrhythmia recurrence and/or CV hospitalization) were evaluated during the follow-up. The relationship between the aforementioned electroanatomical findings and the patients’ outcome was assessed. Twenty patients (12 male, 60%; mean age 40 ± 11 years) undergoing atrial (n = 14; 70%) or ventricular (n = 6; 30%) tachyarrhythmia were included. Acute procedural success (arrhythmia termination and/or no reinduction) was achieved in all the patients. At a mean follow-up of 171 ± 135 weeks, eight patients (40%) had arrhythmia recurrence (4/6 in the ventricular tachycardia group, 67%, 4/14 in the atrial tachycardia group, 28%). Patients with arrhythmia recurrence had a more extensive bipolar scar (P = 0.029) and a larger total mapped area (P = 0.03) than patients without recurrence, and so did the patients with the composite endpoint (P = 0.029 and P = 0.03, respectively). Patients with subsequent CV hospitalization had a larger total mapped area than patients without CV hospitalization (P = 0.017). The presence of a bipolar scar ≥22.95 cm2 predicted arrhythmia relapse (0.039) at the multivariate analysis. Conclusions Patients with ACHD show a high recurrence rate after catheter ablation, especially for ventricular tachycardias. A large bipolar scar at the electroanatomical mapping and total mapped area predict arrhythmia recurrence, likely due to the presence of more extensive reentry circuits. A large total mapped area, which may reflect a greater disease severity, predicts both arrhythmia recurrence and CV hospitalizations. Early referral of ACHD patients for catheter ablation may be a sound strategy in order to perform the procedure in the setting of less advanced heart disease.

Comparison of stationary and dynamic fractional CO2 laser modalities of large burns treatment: Experimental laboratory model

ObjectivesTo experimentally compare two fractional ablative CO2 laser handpieces intended for the treatment of large area burn scars. Each handpiece coverage rate, depth of penetration and application time were measured and compared in a simulation model of large area burns scars using a dynamic/roller handpiece (small footprint) and a stationary/stamping handpiece (large footprint). MethodsA 30 W fractional ablative CO2 laser was applied using 2 different handpieces and footprints on a A4 size paper stack. The handpieces were a stationary (stamping) handpiece with 7 × 7 (49 pixels/square shape) and dynamic (roller) handpiece with 7 × 1 (7 pixels/single row shape). For both handpieces the laser settings were fixed at "High" power (30 W), providing an energy level of 100 mJ/pixel. Both handpieces were applied perpendicular to the surface, with the process repeated for the dynamic handpiece with an angled operation. The depth of laser penetration was assessed by the number of pages of paper having visible holes and burn area coverage time measured under each handpiece/condition. ResultsThe application time was faster and the penetration deeper for the dynamic handpiece compared to the stationary handpiece in both the perpendicular and angled conditions. This study has practical implications for lasers operators to improve time efficacy in large area scars with improved clinical endpoints. ConclusionThe fractional ablative dynamic handpiece demonstrated superior application efficiency compared to the stationary handpiece in the simulated treatment of large surface area burn scars, reducing treatment time with improved depth of penetration.

Fire disturbance promotes biodiversity of plants, lichens and birds in the Siberian subarctic tundra.

Fire shapes the world's terrestrial ecosystems and has been influencing biodiversity patterns for millennia. Anthropogenic drivers alter fire regimes. Wildfires can amplify changes in the structure, biodiversity and functioning of the fast-warming tundra ecosystem. However, there is little evidence available, how these fires affect species diversity and community composition of tundra ecosystems over the long term. We studied long-term fire effects on community composition and diversity at different trophic levels of the food web in the subarctic tundra of Western Siberia. In a space-for-time approach we compared three large fire scars (>44, 28 and 12years old) to unburnt controls. We found that diversity (measured as species richness, Shannon index and evenness) of vascular and non-vascular plants and birds was strongly affected by fire, with the greatest species richness of plants and birds for the intermediate-age fire scar (28years). Species composition of plants and birds still differed from that of the control >44years after fire. Increased deciduous shrub cover was related to species richness of all plants in a hump-shaped manner. The proportion of southern (taiga) bird species was highest in the oldest fire scar, which had the highest shrub cover. We conclude that tundra fires have long-term legacies with regard to species diversity and community composition. They may also increase landscape-scale species richness and facilitate range expansions of more southerly distributed species to the subarctic tundra ecosystem.

Fibula lengthening then centralization for the treatment of pseudoarthrosis at the middle third of tibia with large leg-length discrepancy - A case report.

Introduction and importanceTibial dysplastic pseudoarthrosis associated with large leg-length discrepancy and extensive scarring was a great challenge for orthopedic surgeons. The treatment for these lesions was not defined.Case presentationWe report a 24-year-old case of dysplastic pseudoarthrosis at the middle third of the right tibia with a 10 cm leg-length discrepancy and a 250 medial deviation and 200 internal torsion due to osteomyelitis 14 years previously. She was treated by fibula lengthening then centralization for the treatment of tibial pseudoarthrosis. Eight months after the operation, the patient reported no pain and became capable of walking without an orthosis. X-rays showed full bone union at the proximal tibiofibular synostosis and the lengthening site of the right fibula. The distal tibiofibular synostosis was healing. The range of movement of the knee and ankle was restored.Clinical discussionThis technique was different from the Huntington procedure. A good union between the transposed fibula and the remaining part of the fibula brought a better strength of the reconstructed tibia. The tibial pseudoarthrosis, leg-length discrepancy, and malalignment had been solved by our techniques. The procedure was easy, rapid, and inexpensive without requiring microsurgery skills and special devices.ConclusionLeg lengthening then centralization of ipsilateral fibular graft is an excellent option for reconstruction of a tibial pseudarthrosis with a large leg-length discrepancy. It is a safe, rapid, and inexpensive procedure. The procedure was not difficult, and microvascular skills and special devices were not required.Level of evidenceA case report.

Resurfacing in Facial Burn Sequelae Using Parascapular Free Flap: A Long-Term Experience.

It is difficult to treat large postburn sequelae (scars and defects) over the face. Available methods include skin grafts, local flaps, tissue expansion, and free flaps. These surgical options should be chosen wisely, depending on individual patient requirements and the area involved. In patients with large postburn scars and defects in which the surrounding tissue is also involved, use of free tissue transfer is extremely useful. A retrospective analysis was done between 2011 and 2019 of 52 cases with extensive facial burn deformities in whom secondary reconstruction was done with free parascapular flap cover in our department. Outcome was assessed by a direct questionnaire. There was no complete flap loss in the series. Two cases were re-explored for venous insufficiency and suffered partial marginal necrosis. Twenty patients had to undergo further debulking procedure. Forty-seven patients were satisfied by the final outcome. Postburn facial deformities are difficult to treat; in many cases, there are no local options, and tissue from different regions is to be used for reconstruction. Free parascapular flaps can be used as an effective method in such cases with a high level of patient satisfaction.

Clinical practice guidelines for endoscopic breast surgery in patients with early-stage breast cancer: Chinese Society of Breast Surgery (CSBrS) practice guidelines 2021.

Clinical practice guidelines for endoscopic breast surgery in patients with early-stage breast cancer: Chinese Society of Breast Surgery (CSBrS) practice guidelines 2021.

Laparoscopic Repair of a Large Cesarean Scar Defect after a Prior T-Incision

Study Objective The objective of this video is to demonstrate the feasibility of the laparoscopic repair of a cesarean scar defect after a prior T-incision. Design N/A. Setting Urban, academic tertiary care hospital. Patients or Participants Case report of single patient. Interventions Laparoscopic repair large cesarean scar defect. Measurements and Main Results N/A. Conclusion Laparoscopic cesarean scar defect repair after a prior T-incision is feasible. The objective of this video is to demonstrate the feasibility of the laparoscopic repair of a cesarean scar defect after a prior T-incision. N/A. Urban, academic tertiary care hospital. Case report of single patient. Laparoscopic repair large cesarean scar defect. N/A. Laparoscopic cesarean scar defect repair after a prior T-incision is feasible.

Application of Various Methods to Evaluate the Postoperative Characteristics of Expanded Pedicled Deltopectoral Flap for Large Facial Scars.

The expanded pedicled deltopectoral flap (EPDF) has been widely used to repair large facial scars. Although doctors and patients are usually satisfied with the outcomes, the actual functional recovery and cosmetic effects of EPDF are still unknown. It is, therefore, necessary to objectively investigate the effect of transferred EPDF by using a variety of methods. From January 2008 to December 2018, 52 patients who underwent EPDF surgery at Xijing Hospital were enrolled. Sense of touch, static 2-point discrimination, elasticity, and color were measured. Thermesthesia and algesthesia were also tested. Postoperative scars were evaluated using the patient and observer scar assessment scale. Satisfaction of patients, doctors, and laypersons was investigated. The algaesthesis, thalposis, and rhigosis scores were 4.7 ± 0.7, 3.7 ± 0.9, and 4.5 ± 0.8, respectively. The tactile score was 0.3 ± 0.2 mN, and 2-point discrimination was 10.1 ± 4.8 mm. L ∗ , a ∗ hemoglobin, and melanin content of the flaps were significantly different when compared with normal skin ( P < 0.05). The satisfaction of doctors, patients, and laypersons was 88.5%, 71.2%, and 67.3%, respectively. The higher satisfaction of patients was mainly associated with the smaller color difference between the flap and the surrounding skin, and lower patient and observer scar assessment scale score. These results confirm that excellent functional recovery and reliable cosmetic effects are observed when facial scars are repaired with EPDF. The methods used in this study can be applied to the evaluation of functional recovery and cosmetic outcomes of transferred flaps, which may provide a more comprehensive understanding of flap assessment.

Prescribed Burning Reduces Large, High-Intensity Wildfires and Emissions in the Brazilian Savanna

Brazil has recently (2014) changed from a zero-fire policy to an Integrated Fire Management (IFM) program with the active use of prescribed burning (PB) in federal Protected Areas (PA) and Indigenous Territories (IT) of the Brazilian savanna (Cerrado). PB is commonly applied in the management of fire-prone ecosystems to mitigate large, high-intensity wildfires, the associated emissions, and high fire suppression costs. However, the effectiveness of such fire management in reducing large wildfires and emissions over Brazil remains mostly unevaluated. Here, we aim to fill the gap in the scientific evidence of the PB benefits by relying on the most up-to-date, satellite-derived fire datasets of burned area (BA), fire size, duration, emissions, and intensity from 2003 to 2018. We focused on two Cerrado ITs with different sizes and hydrological regimes, Xerente and Araguaia, where IFM has been in place since 2015. To understand fire regime dynamics, we divided the study period into three phases according to the prevalent fire policy and the individual fire scars into four size classes. We considered two fire seasons: management fire season (MFS, which goes from rainy to mid-dry season, when PBs are undertaken) and wildfires season (WFS, when PBs are not performed and fires tend to grow out of control). Our results show that the implementation of the IFM program was responsible for a decrease of the areas affected by high fire recurrence in Xerente and Araguaia, when compared with the Zero Fire Phase (2008–2013). In both regions, PB effectively reduced the large wildfires occurrence, the number of medium and large scars, fire intensity, and emissions, changing the prevalent fire season from the WFS to the MFS. Such reductions are significant since WFS causes higher negative impacts on biodiversity conservation and higher greenhouse gas emissions. We conclude that the effect on wildfires can still be reduced if effective fire management policies, including PB, continue to be implemented during the coming decades.

Clinical features and early diagnostic clues of chronic granulomatous disease

Objective: To explore the early clinical clues for diagnosis of chronic granulomatous disease (CGD). Methods: One hundred and thirty-nine children with CGD seen in Beijing Children's Hospital from January 2007 to October 2020 were included in this study. The clinical features including age of onset, first presentations, reason for being hospitalized, etiology, imaging features, clues for early diagnosis of all patients were evaluated retrospectively. According to the time of diagnosis, the patients were divided into two groups, cases diagnosed before 2015 and after 2015 and 2015. The time of diagnosis, the length of stay and the hospital charges were compared between the two groups. T test and χ2 test were used for statistical analyses. Results: One hundred and nineteen of the cases were males and 20 were females. The age of onset was 4 months (8 d to 14 years), and 103 cases (74.1%) had onset before 1 year of age. The age at diagnosis was 1.8 years (21 d to 14.7 years), and the time of diagnosis delay was 1 year (7 d to 13.7 years). One hundred and thirty-five cases (97.1%) had pulmonary infection as the main reason for hospitalization, of whom 76 cases (56.3%) had positive pulmonary etiology. One hundred and thirty-six patients (97.8%) were referred cases, of whom 5 were suspected of CGD before referral, and the misdiagnosis rate was as high as 96.3% (131/136). Eight early clues for diagnosis were found, the frequency from high to low, large bacillus Callmette-Guer scar in 99 cases (70.5%), left axillary lymphadenopathy or calcification in 73 cases (52.5%), skin or other lymph node infections in 58 cases (41.7%), skin scars in 50 cases (36.0%), multiple lung nodules in 42 cases (30.2%), perianal abscess in 35 cases (25.2%), pulmonary Aspergillus infection in 26 cases (18.7%) and pulmonary Burkholderia infection in 15 cases (10.8%). A total of 120 cases of CGD were diagnosed by respiratory burst test during hospitalization, including 55 cases diagnosed before 2015 and 65 cases diagnosed after 2015. After using these 8 early diagnosis clues, the cases diagnosed after 2015 had shorter time of diagnosis and the length of stay and lower hospitalization charge than cases diagnosed before 2014, and the difference was statistically significant ((25±7) vs. (10±5) d, (29±7) vs. (18±6) d, (3.7×104±1.2×104) vs. (3.2×104±1.2×104) Yuan, t=13.763, 9.262, 2.381, all P<0.05). Conclusions: Patients with CGD are younger at onset and the diagnosis is delayed. Pulmonary infections are the most common. Large BCG scar, left axillary lymphadenopathy or calcification, skin or other lymph node infections, skin scars, multiple lung nodules, perianal abscesses, pulmonary Aspergillus infection and Burkholderia infection can help early diagnosis of CGD.

Determination of dominant loop in dual loop atrial tachycardia with direct graph mapping: an alternative for entrainment mapping?

Abstract Funding Acknowledgements Type of funding sources: None. Background Entrainment mapping (EM) is an important tool to determine the mechanism of complex reentrant atrial tachycardias (ATs), mostly to distinguish dominant from bystander reentrant loops. However, entrainment maneuvers are challenging, time consuming and risk to end the tachycardia. Purpose Recently, we developed a novel method Directed Graph Mapping (DGM), using concepts of network theory, allowing to automatically determine AT reentry loops from the local activation times (LAT) of any clinical mapping system. DGM showed good performance: it correctly finds ablation target (100 % success rate) on simple AT cases and could automatically determine reentry loops confirmed by the expert electrophysiologist with EM in complex AT cases. Out of 32 single loop cases, 62.5 % was identified correctly with automated DGM and out of 6 true double loop cases, 83.3 %. Lower performance for single reentry complex cases compared to EM was mainly because DGM could not distinguish the dominant loop from additional bystander loops found by DGM. Hence, the purpose of this work was to develop additional algorithms which in case of multiple found DGM loops could automatically find the dominant loop and compare it with the results of EM. Methods We performed multiple simulations of various types of double loop reentry on a patient specific model of the left atrium. Based on a clinical case, double loops were simulated around a scar at the anterior wall (localized reentry) and the mitral valve (MV). LAT maps were determined similar as in the clinic. By varying the size of the scar in multiple steps, we obtained a transition from a regime of a dominant loop around the scar (small scar), to a true double loop and further to a regime of a dominant loop around the MV (large scar). We developed a novel DGM algorithm to determine the dominant loop from the region of collision (ROC) found from the vector field of the wavefront graph. The developed method was also tested on 8 clinical cases of double loop ATs with EM measurements. Results Our algorithm found the location of the ROC and determined the correct dominant loop in 100% of the simulated data. We tested this on 8 clinical cases of AT, and accuracy of the method was 75 %. Conclusions Determining the ROC in case of multiple loops in AT could correctly determine the dominant versus bystander loop, leading to the correct ablation target, without the need for further EM.

Structure Correction for Robust Volume Segmentation in Presence of Tumors.

CNN based lung segmentation models in absence of diverse training dataset fail to segment lung volumes in presence of severe pathologies such as large masses, scars, and tumors. To rectify this problem, we propose a multi-stage algorithm for lung volume segmentation from CT scans. The algorithm uses a 3D CNN in the first stage to obtain a coarse segmentation of the left and right lungs. In the second stage, shape correction is performed on the segmentation mask using a 3D structure correction CNN. A novel data augmentation strategy is adopted to train a 3D CNN which helps in incorporating global shape prior. Finally, the shape corrected segmentation mask is up-sampled and refined using a parallel flood-fill operation. The proposed multi-stage algorithm is robust in the presence of large nodules/tumors and does not require labeled segmentation masks for entire pathological lung volume for training. Through extensive experiments conducted on publicly available datasets such as NSCLC, LUNA, and LOLA11 we demonstrate that the proposed approach improves the recall of large juxtapleural tumor voxels by at least 15% over state-of-the-art models without sacrificing segmentation accuracy in case of normal lungs. The proposed method also meets the requirement of CAD software by performing segmentation within 5 seconds which is significantly faster than present methods.

M-Y Plasty: a Simple Technique for the Reconstruction of Small Periorbital Defects

The goal of this case series analysis is to demonstrate that peri-orbital small to medium-sized skin defects can be treated by a direct closure associated with a M-Y plasty. By crossing the orbital eyelid, this technique allows to avoid large undermining and longer scars that are usually associated with the use of local flaps in this region. Twenty patients were operated on between May 2018 and November 2019, for the removal of periorbital skin tumors. Eleven were at high risk of developing delayed healing, post-operative hematoma, or showed a very thin skin, poorly prone to tolerate a large undermining. Defect size was between 1.5 to 13 cm2. All the defects underwent a direct closure with a M-Y plasty. Eighteen patients healed without any complication. Two had a delayed healing at the Y junction. No hematoma, abscess, cutaneous necrosis, or unaesthetic deformity were recorded. The majority of our patients had significant comorbidities, so that a flap reconstruction was considered too aggressive. We here demonstrate that through a direct closure associated with a plasty, they could all benefit from a oncological excision, with a safe reconstruction and very few complications.