RESUMEN
INTRODUCTION: Breast implant malpositioning is the second most common reason for revisional breast surgery. Multiple correction methods are suggested, depending on the malposition, but most of the methods, such as the inframammary fold incision, result in additional scars. We performed transaxillary endoscopic breast implant bottoming out corrections and used V-Loc thread for capsulorrhaphy. METHODS: Fourteen patients who underwent correction for breast implant bottoming out after transaxillary breast augmentation were included in this study. Transaxillary endoscopic correction was performed using a V-Loc thread. RESULTS: All the 14 patients were satisfied with the result immediately after surgery. One case of overcorrection and one with implant bottoming out occurred, but did not require additional surgery. CONCLUSIONS: Transaxillary endoscopic bottoming out correction is a useful technique for those individuals who underwent primary transaxillary incisional breast augmentation. V-Loc thread is useful for endoscopic capsulorrhaphy. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Asunto(s)
Implantación de Mama , Implantes de Mama , Mamoplastia , Humanos , Implantes de Mama/efectos adversos , Implantación de Mama/efectos adversos , Implantación de Mama/métodos , Mama/cirugía , Mamoplastia/efectos adversos , Mamoplastia/métodos , Cicatriz/cirugía , Resultado del Tratamiento , Estudios Retrospectivos , EstéticaRESUMEN
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.
Asunto(s)
Dermis Acelular , Terapia de Presión Negativa para Heridas , Porcinos , Animales , Gelatina/uso terapéutico , Cicatrización de Heridas , Colágeno/uso terapéutico , Trasplante de Piel/métodosRESUMEN
Treatment of facial palsy is essential because neglecting this disorder can lead to serious sequelae and further damage. For an objective evaluation and consistent rehabilitation training program of facial palsy patients, a clinician's evaluation must be simultaneously performed alongside quantitative evaluation. Recent research has evaluated facial palsy using 68 facial landmarks as features. However, facial palsy has numerous features, whereas existing studies use relatively few landmarks; moreover, they do not confirm the degree of improvement in the patient. In addition, as the face of a normal person is not perfectly symmetrical, it must be compared with previous images taken at a different time. Therefore, we introduce three methods to numerically approach measuring the degree of facial palsy after extracting 478 3D facial landmarks from 2D RGB images taken at different times. The proposed numerical approach performs registration to compare the same facial palsy patients at different times. We scale landmarks by performing scale matching before global registration. After scale matching, coarse registration is performed with global registration. Point-to-plane ICP is performed using the transformation matrix obtained from global registration as the initial matrix. After registration, the distance symmetry, angular symmetry, and amount of landmark movement are calculated for the left and right sides of the face. The degree of facial palsy at a certain point in time can be approached numerically and can be compared with the degree of palsy at other times. For the same facial expressions, the degree of facial palsy at different times can be measured through distance and angle symmetry. For different facial expressions, the simultaneous degree of facial palsy in the left and right sides can be compared through the amount of landmark movement. Through experiments, the proposed method was tested using the facial palsy patient database at different times. The experiments involved clinicians and confirmed that using the proposed numerical approach can help assess the progression of facial palsy.
Asunto(s)
Parálisis Facial , Bases de Datos Factuales , Humanos , Imagenología Tridimensional/métodos , MovimientoRESUMEN
BACKGROUND: Contralateral perfusion of zones II and IV is critical to estimate the amount of fat necrosis and determine intraoperative flap sacrifice during autologous breast reconstruction. We aimed to determine whether perfusion of the contralateral side was affected by the peak flow velocity in the feeding vessels in the deep inferior epigastric artery (DIEA) perforator free flap reconstructions. METHODS: This was a retrospective review of patients who received DIEA perforator flap for autologous breast reconstruction from February to July 2020. Intraoperative indocyanine green (ICG) angiography and measurement software (Image J) were used to validate the perfusion of the contralateral side of the flap. Peak flow in the vessels was measured with duplex color Doppler and linear correlation was used to analyze the association between perfusion and blood flow velocity. RESULTS: Forty-two patients received a DIEP flap. The average age of the patients was 48.5 years, and body mass index was 23.84 kg/m2. Peak flow velocity of the internal mammary artery (IMA) was significantly higher than that of the DIEA (p <0.05). Contralateral perfusion confirmed by ICG angiography was higher in the IMA than in the DIEA (p <0.05). A linear correlation was found between peak speed (p = 0.045) and ICG perfusion length (p = 0.00003). CONCLUSION: The status of flap perfusion depends on the feeding vessel. The velocity of blood flow between IMA and DIEA is different, and the flap perfusion varies accordingly. Therefore, ICG angiography should be performed after anastomosis at the recipient site for an accurate assessment.
Asunto(s)
Mamoplastia , Colgajo Perforante , Arterias Epigástricas/cirugía , Etilaminas , Humanos , Mamoplastia/métodos , Persona de Mediana Edad , Colgajo Perforante/irrigación sanguínea , PerfusiónRESUMEN
BACKGROUND: Worm's eye view photograph has been widely used for anthropometric analysis. However, it is difficult to secure objectivity because it cannot be captured at a constant head-up degree. This study aimed to analyze whether anthropometric nasal measurements in worm's eye view differ from the actual values. METHODS: A total of 40 patients with unilateral cleft lip nasal deformities were included. The 30° and 60° head-tilted two-dimensional (2D) photographs were captured from the three-dimensional (3D) images. The real measurements were obtained from 3D images and 2D measurements were obtained from the captured images. The cleft/non-cleft side ratios of the nostril height, width, and alar base width were compared between 3D and 2D images. RESULTS: There was a significant difference in the nostril height between the 3D and 30° values (3Dâ=â0.82, 30°â=â0.92, Pâ<â0.001) but no meaningful difference was noted between the 3D and 60° values (3Dâ=â0.82, 60°â=â0.84, Pâ=â0.31). There was no significant difference in the nostril width among the 30°, 60°, and 3D values. A significant difference was found in the alar base width between the 3D values and both the 30° (3Dâ=â0.998, 30°â=â1.04, Pâ=â0.026) and 60° (3Dâ=â0.998, 30°â=â1.03, Pâ=â0.029) values. CONCLUSIONS: This study demonstrates that 2D photographs do not accurately reflect actual values. The nostril height and alar width ratio can be changed depending on the head-up position. The 3D systems are more accurate and less affected by the subject's head position. Therefore, the 3D imaging system is advocated for the anthropometric analysis of unilateral cleft lip nasal deformity.
Asunto(s)
Labio Leporino , Fisura del Paladar , Rinoplastia , Antropometría , Labio Leporino/diagnóstico por imagen , Labio Leporino/cirugía , Fisura del Paladar/diagnóstico por imagen , Fisura del Paladar/cirugía , Humanos , Nariz/diagnóstico por imagen , Nariz/cirugía , Reproducibilidad de los Resultados , Resultado del TratamientoRESUMEN
BACKGROUND: Orthognathic surgery has become more popular to slenderize a wide lower face and to improve facial esthetics in Asian patients with normal occlusion. Clockwise rotation (CR) of the maxillomandibular complex (MMC) steepens the mandibular plane. This study performed a quantitative analysis on the influence of CR on slenderness of the lower face from the frontal view. PATIENTS AND METHODS: This retrospective study included 36 female patients with Angle Class I occlusion and skeletal Class III pattern. The subjects underwent CR of the MMC without perioperative orthodontic treatment and change in the occlusion only for the purpose of esthetic improvement. Linear and angular variables were measured on a cephalogram and three-dimensional computed tomography (3D CT) obtained before and at least 6 months after surgery. Data were analyzed using paired t tests and Spearman correlations. Univariate regression analysis was used to predict the postoperative change according to the amount of posterior impaction. RESULTS: The mean posterior impaction was 3.81 mm. All mandibular plane angle (MPA) measurements were increased (ranged from 5.69° to 13.12°, p < 0.001), exhibiting a significant correlation with the amount of posterior impaction. Bigonial width measurements were decreased after surgery (ranged from 4.97 to 5.51 mm, p < 0.001). Among the MPAs derived from the 3D CT, the coronal projection from the frontal view exhibited a discrepancy between right and left side. CONCLUSIONS: The changes in linear and angular measurements in this study indicate that the lower face becomes narrower and more slender as the MMC rotates in a clockwise direction. Orthognathic surgery with CR has the advantage of increasing the MPAs and obtaining natural soft tissue contouring while minimizing the amount of bone resection. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266c .
Asunto(s)
Imagenología Tridimensional , Maloclusión de Angle Clase III/diagnóstico por imagen , Maloclusión de Angle Clase III/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Adulto , Análisis de Varianza , Cefalometría/métodos , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Modelos Lineales , Osteotomía Mandibular/métodos , Osteotomía Maxilar/métodos , Recuperación de la Función , Estudios Retrospectivos , Rotación , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento , Adulto JovenRESUMEN
The etiology and pathophysiology of delayed inflammatory reactions caused by hyaluronic acid fillers have not yet been elucidated. Previous studies have suggested that the etiology can be attributed to the hyaluronic acid filler itself, patient's immunological status, infection, and injection technique. Hyaluronic acid fillers are composed of high-molecular weight hyaluronic acids that are chemically cross-linked using substances such as 1,4-butanediol diglycidyl ether (BDDE). The mechanism by which BDDE cross-links the two hyaluronic acid disaccharides is still unclear and it may exist as a fully reacted cross-linker, pendant cross-linker, deactivated cross-linker, and residual cross-linker. The hyaluronic acid filler also contains impurities such as silicone oil and aluminum during the manufacturing process. Impurities can induce a foreign body reaction when the hyaluronic acid filler is injected into the body. Aseptic hyaluronic acid filler injections should be performed while considering the possibility of biofilm formation or delayed inflammatory reaction. Delayed inflammatory reactions tend to occur when patients experience flu-like illnesses; thus, the patient's immunological status plays an important role in delayed inflammatory reactions. Large-bolus hyaluronic acid filler injections can induce foreign body reactions and carry a relatively high risk of granuloma formation.
RESUMEN
INTRODUCTION: Primary lymphedema is characterized by lymphatic dysplasia in which one variant is Milroy's disease. The association with congenital chylothorax is even rarer with poor outcome. This is the first report to utilize peripheral lymphovenous anastomosis (LVA) and lymph node to vein anastomosis (LNVA) for the management of such condition. METHODS: Retrospective chart review of patients with Milroy's disease with complication of chylothorax between 2019 till 2023 was performed. Clinical assessment and radiological investigations were reviewed. RESULTS: Six patients with mean age of 12±3.9 years and disease duration of 10.5±2.8 years were reviewed. Three had ISL stage 3 while others had stage 2 late disease. All had bilateral lower extremity lymphedema and chylothorax with history of chest tube drainage. After LVA and LNVA, significant reduction in extremity volume was noted (p=0.028) along with near complete resolution of chylothorax was noted during the long-term follow-up (32 ±17.9 months). CONCLUSION: Milroy's disease complicated with chylothorax remains to be challenging. This is the first report utilizing peripheral bypass (LVA and LNVA) which resulted in improvement of both lower extremity lymphedema and chylothorax. The utility of this approach represents a promising modality in the management of this devastating condition.
RESUMEN
The mammalian target of rapamycin (mTOR) inhibitors are used to prevent organ transplant rejection and are preferred over other immunosuppressants due to its low nephrotoxicity. However, mTOR inhibitors have been associated with various adverse effects including lymphedema. Although rare in incidence, previously known treatments for mTOR inhibitor-induced lymphedema were limited to discontinuation of related drugs and complex disruptive therapy with variable results. In this article, three patients who developed lymphedema in their lower limbs after using mTOR inhibitors, including two bilateral and one unilateral case, were treated with physiologic surgery methods such as lymphovenous anastomosis (LVA) and lymph node transfer. The efficacy of the treatment was evaluated. In the three cases described, cessation of the drug did not lead to any reduction in edema. The use of LVA and lymph node transfer resulted in early reductions in volume but failed to sustain over time. All patients underwent secondary nonphysiologic surgery such as liposuction resulting in sustained improvement. This series presents the first physiologic approach to mTOR inhibitor-induced lymphedema. Although further study is warranted, the physiologic surgical options may have limited success and nonphysiologic options may offer better sustainable results.
RESUMEN
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.
RESUMEN
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.
RESUMEN
Breast augmentation can cause severe postoperative pain, leading to an increased length of hospital stay. Postoperative pain management following breast surgery has traditionally involved intravenous and oral analgesics. However, the misuse of opioids can cause severe complications. As a result, several alternative methods have been suggested. Fifty patients were included in this study. All the patients underwent dual-plane pocket dissection using the transaxillary approach and received smooth-type breast implants. The intervention group included 25 patients who received PF72 combined with ropivacaine, and the control group included 25 patients who received only bupivacaine. The Numerical Rating Scale (NRS) score was used to evaluate each patient's pain. Three hours after the surgery, the average NRS scores of the control and intervention groups were 3.75 and 2.48, respectively. Six hours after the operation, the NRS scores of the control and intervention groups increased to 4.77 and 3.02, respectively. PF72 combined with ropivacaine was more effective than only bupivacaine for pain control in patients who underwent breast augmentations.
RESUMEN
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.
Asunto(s)
Biónica , Nervios Periféricos , Animales , Conejos , Electromiografía , Nervios Periféricos/fisiología , Prótesis e Implantes , Regeneración Nerviosa/fisiologíaRESUMEN
This study aimed to restore upper lip symmetry and minimize tissue sacrifice using a curved line design and wire technique and analyze the postoperative outcomes. In this retrospective study, medical records of patients with complete unilateral cleft lip who underwent unilateral cheiloplasty between August 2017 and February 2019 were reviewed. The postoperative clinical photos were analyzed to determine vertical, diagonal philtral heights and the horizontal lengths of the upper lip. The average of the cleft side to non-cleft side length ratios were compared between the curved line group and conventional group. At 3, 6, and 12 months, the average vertical length ratios were significantly greater in the curved line group than in the conventional group (0.927-0.823, p = 0.007; 0.940 to 0.885, p = 0.037; and 0.947 to 0.883, p = 0.040, respectively), but the average horizontal length ratios were not significantly different between the two groups. Within the limitations of the study it seems that curved line cheiloplasty aids in preventing short lip deformity development at regular term without significantly sacrificing the horizontal length and, therefore, should be adopted whenever appropriate.
Asunto(s)
Labio Leporino , Fisura del Paladar , Procedimientos de Cirugía Plástica , Labio Leporino/cirugía , Fisura del Paladar/cirugía , Humanos , Lactante , Labio/cirugía , Mucosa Bucal/cirugía , Procedimientos de Cirugía Plástica/métodos , Estudios RetrospectivosRESUMEN
BACKGROUND: Perforator flaps have revolutionized lower limb reconstruction by offering single-stage thin, pliable coverage with an excellent aesthetic match. Although anastomosis of the flap to a major artery remains the gold standard, perforator-to-perforator anastomosis has several advantages, including expedient recipient dissection and increased recipient options in vessel-depleted extremities. The aim of this study was to compare flap survival when a perforator or major artery was used as a recipient vessel. METHODS: A retrospective cohort of free perforator flaps for lower limb reconstruction was reviewed. Demographics, comorbidities, vascular status, defect characteristics, operative details, and complications were recorded. Outcomes for perforator and major artery recipients were compared. RESULTS: Four hundred twenty-three flaps were performed for various reasons using perforator flaps. The total limb salvage rate was 98.8 percent. Total and partial flap failure rates were 6.1 percent and 9.0 percent, respectively. Comparing perforator recipients [n = 109 (25.8 percent)] to major artery recipients [n = 314 (74.2 percent)], there was no significant difference in total (p = 0.746) or partial flap failure (p = 0.212). Significant factors between the groups included larger flap size with major artery recipients (p = 0.001) and shorter operative time when using a perforator recipient (p = 0.012). CONCLUSIONS: Perforator-to-perforator anastomosis is a reliable option that affords equivalent rates of flap success compared to major artery anastomosis in lower extremity reconstruction. The authors advocate using a major artery recipient in defects where the axial vessels are easily accessible. A perforator recipient is a viable alternative in defects where access to the axial vessels is inconvenient and in patients with limited recipient options. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.
Asunto(s)
Arterias/cirugía , Colgajos Tisulares Libres/irrigación sanguínea , Extremidad Inferior/cirugía , Colgajo Perforante/irrigación sanguínea , Procedimientos de Cirugía Plástica/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Estudios de Seguimiento , Colgajos Tisulares Libres/trasplante , Humanos , Extremidad Inferior/irrigación sanguínea , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Colgajo Perforante/trasplante , Estudios Retrospectivos , Adulto JovenRESUMEN
Thread lift boasts the advantage of minimal invasion for facial rejuvenation and has been increasingly used nowadays. The purpose of this study was to evaluate the outcomes and safety of elastic thread when it was used in the modified minimal access cranial suspension (MACS) lift for rejuvenation of the lower and middle third of the face.Forty-six patients with sagging and laxity of the lower face treated by the elastic thread modified MACS lift from December 2015 and December 2017 were enrolled in this study. A retrospective chart review was conducted. The degree of Wrinkle Severity Rating Scale (WSRS) score and satisfaction score were evaluated immediately, 6 months and 12 months after procedure. Complications during the study were also recorded.All the patients were female, with a mean age of 50.7â±â6.4 years and a mean follow-up period of 15.4â±â2.1 months. The mean operation time was 114â±â13âminutes. For the left face, the mean WSRS score was 4.0â±â0.8 preoperatively and 3.1â±â0.8 on the 1-year follow-up; and 4.1â±â0.9 and 3.1â±â0.7 on the right face (Pâ<â.01). Thirty-nine (84.8%) patients considered the long-term results satisfactory. There were no major complications during the follow-up period.The elastic thread modified MACS lift is a minimally invasive, effective and safe method to improve lagging middle and lower third of the face without significant postoperative morbidity or complications.
Asunto(s)
Cara , Ritidoplastia/métodos , Técnicas de Sutura , Adulto , Elasticidad , Femenino , Humanos , Persona de Mediana Edad , Procedimientos Quirúrgicos Mínimamente Invasivos , Tempo Operativo , Satisfacción del Paciente , Rejuvenecimiento , Envejecimiento de la PielRESUMEN
BACKGROUND: Venous super-drainage can improve flap survival not only because it prevents congestion, but also because it affects the dominant circulation in multi-territory thin skin flaps. We aimed to evaluate the survival of various flap areas and detect vascular changes in artery-based, four-territory skin flaps after different distal venous drainage procedures. METHODS: 4 x 12 cm sized flaps were elevated based only on the deep circumflex iliac artery. Fifty rats were divided into five groups, as follows: group 1, flaps drained with the deep circumflex iliac vein; group 2, flaps drained with the ipsilateral superficial inferior epigastric vein; group 3, flaps drained with the contralateral superficial inferior epigastric vein; group 4, flaps drained with the contralateral deep circumflex iliac vein; and group 5, flaps super-drained with the contralateral deep circumflex iliac vein. On the fourth postoperative day, the survival of the flaps was assessed by measuring the necrotic and surviving areas, and vascular changes were evaluated angiographically. RESULTS: Compared to flaps with only arterial-based pedicles, most flaps with distant drainage showed significantly greater survival. The flap survival area percentages were 37.82 ± 5.01%, 49.23 ± 10.47%, 68.22 ± 9.24%, 83.90 ± 12.03%, and 89.17 ± 10.42% for groups 1, 2, 3, 4, and 5, respectively. Furthermore, distal vein drainage above the ventral midline resulted in significantly better flap survival. Super-drainage and drainage via the most distal vein resulted in similar flap survival. CONCLUSIONS: Distal vein drainage is effective for increasing survival in artery-based flaps.