Hydrodynamic Evaluation of a Filtering Hydrocyclone for Solid Particle/Water Separation.

A conventional hydrocyclones is a versatile equipment with a high processing capacity and low maintenance cost. Currently, several studies aim to alter the typical structure of the conventional hydrocyclone in order to modify its performance and purpose. For this, filtering hydrocyclones have emerged, where a porous membrane replaces the conic or cylindrical wall. During the operation of this equipment, in addition to the traditionally observed streams (feed, underflow, and overflow), there is a liquid stream resulting from the filtration process, commonly referred to as filtrate. This work proposes to numerically investigate the solid particle/liquid water separation process in a filtering hydrocyclone using the commercial software Ansys CFX® 15.0. The proposed mathematical model for the study considers three-dimensional, steady state and turbulent flow, using the Eulerian-Eulerian approach and the Shear Stress Transport (SST) turbulence model. This study presents and analyzes the volume fraction, velocity, and pressure fields, along with flowlines and velocity profiles. The results indicate that the proposed model effectively captures the fluid dynamic behavior within the filtering hydrocyclone, highlighting higher pressures near the porous membrane and a higher concentration of solid particles in the conical region, with water being more concentrated in the cylindrical part of the hydrocyclone. Additionally, the findings show that the volumetric flow rate of the filtrate significantly influences the internal flow dynamics, with conventional hydrocyclones demonstrating higher pressure gradients compared to the proposed filtering hydrocyclone.

Investigating the Dialysis Treatment Using Hollow Fiber Membrane: A New Approach by CFD.

Due to the increase in the number of people affected by chronic renal failure, the demand for hemodialysis treatment has increased considerably over the years. In this sense, theoretical and experimental studies to improve the equipment (hemodialyzer) are extremely important, due to their potential impact on the patient's life quality undergoing treatment. To contribute to this research line, this work aims to study the fluid behavior inside a hollow fiber dialyzer using computational fluid dynamics. In that new approach, the blood is considered as multiphase fluid and the membrane as an extra flow resistance in the porous region (momentum sink). The numerical study of the hemodialysis process was based on the development of a mathematical model that allowed analyzing the performance of the system using Ansys® Fluent software. The predicted results were compared with results reported in the literature and a good concordance was obtained. The simulation results showed that the proposed model can predict the fluid behavior inside the hollow fiber membrane adequately. In addition, it was found that the clearance decreases with increasing radial viscous resistance, with greater permeations in the vicinity of the lumen inlet region, as well as the emergence of the retrofiltration phenomenon, characteristic of this type of process. Herein, velocity, pressure, and volumetric fraction fields are presented and analyzed.

Hydrodynamic and Performance Evaluation of a Porous Ceramic Membrane Module Used on the Water-Oil Separation Process: An Investigation by CFD.

Wastewater from the oil industry can be considered a dangerous contaminant for the environment and needs to be treated before disposal or re-use. Currently, membrane separation is one of the most used technologies for the treatment of produced water. Therefore, the present work aims to study the process of separating oily water in a module equipped with a ceramic membrane, based on the Eulerian-Eulerian approach and the Shear-Stress Transport (SST k-ω) turbulence model, using the Ansys Fluent® 15.0. The hydrodynamic behavior of the water/oil mixture in the filtration module was evaluated under different conditions of the mass flow rate of the fluid mixture and oil concentration at the entrance, the diameter of the oil particles, and membrane permeability and porosity. It was found that an increase in the feed mass flow rate from 0.5 to 1.5 kg/s significantly influenced transmembrane pressure, that varied from 33.00 to 221.32 kPa. Besides, it was observed that the particle diameter and porosity of the membranes did not influence the performance of the filtration module; it was also verified that increasing the permeability of the membranes, from 3 × 10-15 to 3 × 10-13 m2, caused transmembrane pressure reduction of 22.77%. The greater the average oil concentration at the permeate (from 0.021 to 0.037 kg/m3) and concentrate (from 1.00 to 1.154 kg/m3) outlets, the higher the average flow rate of oil at the permeate outlets. These results showed that the filter separator has good potential for water/oil separation.

Oily Water Separation Process Using Hydrocyclone of Porous Membrane Wall: A Numerical Investigation.

This research aims to study the process of separating water contaminated with oil using a hydrocyclone with a porous wall (membrane), containing two tangential inlets and two concentric outlets (concentrate and permeate), at the base of the equipment. For the study, the computational fluid dynamics technique was used in a Eulerian-Eulerian approach to solve the mass and linear momentum conservation equations and the turbulence model. The effects of the concentration polarization layer thickness and membrane rejection coefficient on the permeate flow, hydrodynamic behavior of the fluids inside the hydrocyclone, and equipment performance were evaluated. Results of the velocity, transmembrane pressure and oil concentration profiles along the equipment, and hydrocyclone performance are presented and analyzed. The results confirmed the effect of the membrane rejection coefficient on the equipment performance and the high potential of the hydrocyclone with a porous wall to be used in the oil-water mixture separation.

A New Design of Tubular Ceramic Membrane Module for Oily Water Treatment: Multiphase Flow Behavior and Performance Evaluation.

Petroleum has been extracted from oil reservoirs using different techniques. This activity is accompanied for a large amount of water and sometimes mixed with gas. This produced water has a high oil concentration and other toxic chemical compounds, thus, it must be treated to be reused or released to environment according to environmental protection regulations. Currently, ceramic membrane technology has been employed in the wastewater treatment, due to its high benefit-cost ratio. In this sense, this work aims to study the oil-water mixture separation process using a new configuration of tubular ceramic membrane module by computational fluid dynamic (ANSYS Fluent software). The proposed model is composed of mass and linear momentum conservation equations coupled to Darcy's law and SST k-ω turbulence model. Results of the volumetric fraction, pressure, and velocity distribution of the oil and water phases are presented and discussed. The results indicated that the proposed model and new device both have great potential to be used on the water/oil separation process and that the transmembrane pressure remains constant in the axial direction and decreases radially through the membranes, indicating an efficient system that favors the transport of clean water and oil retention.

Impact of Permeable Membrane on the Hydrocyclone Separation Performance for Oily Water Treatment.

In the oil industry and academy, the treatment of water contaminated with oil using conventional hydrocyclones and membranes has been an alternative to meet the requirements established by environmental control agencies. However, such equipment is not fully efficient in the treatment of much diluted oily water, with both presenting restrictions in their performance. In this sense, the present work proposes to study the separation process of oily water using a new configuration of hydrocyclone, equipped with a porous ceramic membrane in the conical part's wall (filtering hydrocyclone). For the theoretical study, a Eulerian-Eulerian approach was applied to solve the mass and momentum conservation equations, and the turbulence model, using the computational fluid dynamics technique. The results of the velocity, pressure and volumetric fraction of the involved phases, and the separation performance of the hydrocyclone, are presented, analyzed, and compared with those obtained with a conventional hydrocyclone. The results confirmed the high potential of the proposed equipment to be used in the separation of the water and oil mixture.

Cashew gum as a sol-gel precursor for green synthesis of nanostructured Ni and Co ferrites.

The aim of this work consists in the use of cashew gum (Anacardium occidentale), a naturally occurring tropical specie from the Brazilian northeastern coast, for the synthesis of CoFe2O4 (CF) and NiFe2O4 (NF) nanoparticles. The structural, morphological and vibrational properties of nanoparticles were characterized by analytical and spectroscopic techniques such as X-ray diffraction (XRD), FTIR, Raman spectroscopy, TEM, SAED and TG. Magnetic properties were investigated through Mössbauer spectroscopy and DC magnetometry. The XRD results showed single phase nanoparticles with space group Fd-3m and crystallite size of 7.4 and 6.0 for CF and NF, respectively. TEM images showed agglomerated particles with mode sizes of 5.0 and 6.5 nm for CF and NF. SAED confirmed the crystalline spinel structure. The TGA and FTIR showed the presence of a carbonaceous material in the samples. FTIR and Raman spectroscopy demonstrated vibrational modes characteristic of metal­oxygen bonds in the tetrahedral and octahedral sites. Magnetization measurements showed that both samples are superparamagnetic at 300 K. The Mössbauer spectra at 90 K showed the presence of single-phase CF and NF.

Life cycle inference and phylogeny of Ortholinea labracis n. sp. (Myxosporea: Ortholineidae), a parasite of the European seabass Dicentrarchus labrax (Teleostei: Moronidae), in a Portuguese fish farm.

Ortholinea labracis n. sp. is described and its life cycle is inferred from a Southern Portuguese fish farm, with basis on microscopic and molecular procedures. This myxosporean parasite infects the urinary bladder of the European seabass Dicentrarchus labrax and the intestinal epithelium of a marine oligochaete of the genus Tectidrilus. Myxospores subspherical in valvular view and ellipsoidal in sutural view measuring 7.6 ± 0.3 (6.8-8.7) µm in length, 7.2 ± 0.2 (6.7-7.7) µm in width and 6.5 ± 0.4 (5.8-7.7) µm in thickness. Two polar capsules, 3.0 ± 0.2 (2.6-3.4) µm long and 2.4 ± 0.1 (2.0-2.9) µm wide, located at the same level, but with divergent orientation and opening to opposite sides of the suture line. Sequencing of the SSU rRNA gene revealed a similarity of 100% between the analysed myxospores and triactinomyxon actinospores. The phylogenetic setting of O. labracis n. sp. shows subgrouping in correlation with tissue tropism, but identifies this parasite as another exception to the main division of Myxosporea into the main freshwater and marine lineages.

Intracranial hypertension due to meningioma of the unique transverse sinus.

We describe a 28-year-old woman with intracranial hypertension due to a meningioma invading the unique transverse sinus (with absent contralateral sinus). Clinical remission and normalization of orbital echography were obtained by resection of the intradural tumor and peeling of the dural attachment. In such cases, resection and reconstruction of the involved sinus segment is at high risk of venous infarction. Endovascular stenting of the obstructed sinus is a valid alternative when the stenosis is not remarkable. Single tumor removal may lead to partial sinus decompression and increased venous flow, resulting in long-term clinical remission.

Paravertebral high cervical chordoma. A case report.

Spinal chordomas are more often located on the midline and are associated with marked destruction of the vertebral bodies. We report a rare case of large cervical (C2-C3) right lateral paravertebral chordoma extending into the spinal canal through a very enlarged intervertebral foramen. The tumor was initially diagnosed as a mucous adenocarcinoma on a percutaneous needle biopsy. However, the neuroradiological features, including the well-defined tumor margins, the regular and sclerosing lytic bone changes with regular enlargement of the intervertebral C2-C3 foramen, were in favor of a more slowly growing lesion, such as schwannoma or neurofibroma. At surgery a well-demarcated capsulated tumor involving the nerve root was partially resected. Histology was in favor of a low-grade chordoma (Ki-67/MIB-1<1%). Postoperative proton beam therapy was also performed. The differential neuroradiological diagnosis is discussed.

Morfologia e biometria do timo em araras dos gêneros Ara e Anodorhynchus / Morphology and biometry of the thymus gland in macaw of Ara and Anodorhynchus genera

Foram utilizados 12 exemplares de Ara ararauna - seis fêmeas e seis machos -, cinco exemplares de Ara chloropterus (uma fêmea e quatro machos) e dois exemplares de Anodorhynchus hyacinthinus - uma fêmea e um macho -, todos adultos, doados por criadouro particular, após óbito natural. Os lobos foram dissecados e medidos com paquímetro - comprimento x largura x espessura - e analisados quanto ao peso, à topografia e à morfologia individual. Independentemente do gênero, foram identificados, em 17 casos (89,5%), lobos tímicos nos antímeros cervicais esquerdo e direito, e em oito casos (42,1%), lobos na cavidade celomática. Os lobos apresentaram formatos alongados - 52,6% -, arredondados - 21,1% - ou ovalados - 15,8% -, posicionados preferencialmente ventromedialmente ao longo do plexo vasculoneural do pescoço, com número médio de cinco lobos por antímero, tamanho médio de 0,49cm de comprimento, 0,12cm de largura e 0,05cm de espessura e peso médio de 0,076g.

Twelve samples of Ara ararauna - six females and six males -, five samples of Ara chloropterus (one female and four males) and two samples of Anodorhynchus hyacinthinus (one female and one male), all adults from a Breeding Park, were used after natural death. The lobes were dissected and measured with electronic calliper (length x width x thickness) and analyzed taking their weight, topography and individual morphology into account. Regardless of gender, 89.5% of the cases presented timic lobes in the left and right cervical antimere, and 42.1% of the cases presented lobes in the celomatic cavity. The lobes were shown in shapes - long (52.6%), round (21.1%) or oval (15.8%), positioned mostly ventromedially, along the neurovascular plexus of the neck, with an average of five lobes per antimere, and an average size of 0.49cm length, 0.12cm width, and 0.05cm thick and average weight of 0.076g.

Shortened interval of long-acting octreotide administration is effective in patients with well-differentiated neuroendocrine carcinomas in progression on standard doses.

BACKGROUND: In patients with well-differentiated (WD) neuroendocrine tumors (NET), long-acting octreotide (LAR), conventionally administered at a dose of 30 mg every 28 days, has well-documented anti-secretive but limited antiproliferative effects. AIM: The objective of this study was to evaluate a different schedule of LAR treatment consistent with a shorter interval between administrations (21 days) in WDNET patients with progressive disease at standard-dose interval. SUBJECTS AND METHODS: Twenty-eight patients followed for diagnosis and therapy of WDNET who had tumor progression during therapy with LAR 30 mg every 28 days were enrolled. Clinical, biological, and objective tumor response was evaluated after LAR 30 mg every 21 days. Time to progression was also evaluated after LAR 30 mg every 21 days and compared to LAR 30 mg every 28 days. RESULTS: The treatment with LAR 30 mg every 21 days resulted in complete and partial control of clinical symptoms in 40% and 60% of cases, respectively. Circulating neuroendocrine markers were significantly decreased in 30% of cases. A stabilization of disease was obtained in 93% and objective response in 7%. The median time to progression was significantly longer by using the shortened interval of LAR administration as compared to the standard one (30 vs 9 months, p<0.0001). The treatment was safe and well tolerated. CONCLUSIONS: The shortened schedule of LAR administration was able to re-institute control of clinical symptoms, to decrease level of circulating neuroendocrine markers and to increase time to progression in patients previously escaping from a standard schedule treatment.

Everolimus is an active agent in medullary thyroid cancer: a clinical and in vitro study.

Everolimus, an mTOR inhibitor, which has been demonstrated to induce anti-tumour effects in different types of neuroendocrine tumours, has never been evaluated in patients with medullary thyroid cancer (MTC). The aim of this study was to evaluate the in vitro and in vivo effects of everolimus in combination with octreotide in MTC. Two patients with progressive metastatic MTC and high calcitonin levels were treated with everolimus 5-10 mg/day. Both patients were under treatment with octreotide LAR at the study entry. An in vitro study was also performed to assess everolimus effects on MTC cell lines (TT and MZ-CRC-1 cells). A tumour response was observed in both patients. Serum calcitonin decreased by 86% in patient 1 and by 42% in patient 2. In TT and MZ-CRC-1 cells, everolimus induced a significant dose-dependent inhibition in cell proliferation. This effect seems to be related to a cell cycle arrest in G(0) /G(1) phase in both cell lines and to the induction of cellular senescence in TT cells. Everolimus in combination with octreotide may be active as anti-tumour therapy in patients with progressive metastatic MTC, suggesting to further evaluate this agent in MTC patients in a large prospective study.

Clinical and prognostic implications of the genetic diagnosis of hereditary NET syndromes in asymptomatic patients.

Neuroendocrine tumors (NETs) can be sporadic or they can arise in complex hereditary syndromes. Patients with hereditary NETs can be identified before the development of tumors by performing genetic screenings. The aim of the study was to evaluate the clinical and prognostic impact of a preclinical genetic screening in subjects with hereditary NET syndromes. 46 subjects referred for hereditary NET syndrome [22 MEN1, 12 MEN2, 12 Familial Paragangliomatosis (FPGL)] were enrolled and divided in 2 groups (group A, 20 subjects with clinical appearance of NET before the genetic diagnosis; group B, 26 subjects with genetic diagnosis of hereditary NET syndromes before the clinical appearance of NETs). The main outcome measures were severity of disease, prognosis, and survival. The rate of surgery for MEN1-, MEN2-, FPGL4-related tumors was 90% in group A and 35% in group B (p<0.01). Both symptoms related to tumors and symptoms related to therapies were significantly less frequent in group B than in group A (p<0.05). Tumor stage was locally advanced or metastatic in 50% of group A and in no one of group B (p<0.01). The mortality rate was 25% in group A and 0% in group B (p<0.05). An early genetic screening for hereditary NET syndromes results in an improvement in clinical presentation and morbidity. A potential impact of the genetic screening on the mortality rate of these subjects is suggested and needs to be investigated in further and more appropriate studies.

Thyroid function in Fabry disease before and after enzyme replacement therapy.

UNLABELLED: AM: Patients with Fabry disease (FD), a genetic disorder caused by lysosomal a-galactosidase-A enzyme deficiency and characterized by a systemic accumulation of globotriaosylceramides, present high prevalence of subclinical hypothyroidism. The pathogenic mechanism is thought not to be related to anti-thyroid autoimmunity and may be dependent by intra-thyroid lipid accumulation. In this study, it was investigated whether thyroid function recovers in FD after long-term enzyme replacement therapy (ERT). METHODS: Study population included 14 FD patients (7 females, 7 males, aged 21-62 years) and 14 sex- and age-matched normal subjects. Thyroid function was evaluated in each patient at baseline and after the beginning of ERT with rh-a-galactosidase-A (1 mg/kg/BW every 2 weeks) for three years. RESULTS: TSH levels were higher in FD patients than in controls (P<0.05). In FD patients, TSH levels were higher before than after ERT (1.9±0.2 vs 1.2±0.2 mU/L, P<0.01) while fT3 and fT4 levels were normal at baseline and unchanged after ERT. At baseline, TSH levels were >3 mU/L in three patients and normalize after ERT. Anti-Tg and/or anti-TPO titres were positive in 14% of patients and 21% of controls. After ERT, the rate of autoimmunity was unchanged. At the thyroid ultrasonography, a slight hypoechoic pattern was found in 71% of patients at baseline and decreased to 43% after ERT. CONCLUSION: Primary hypothyroidism in FD patients is reverted after long-term ERT. A screening of thyroid function and periodical re-evaluation during ERT is mandatory in all FD patients.

Cinacalcet hydrochloride in combination with alendronate normalizes hypercalcemia and improves bone mineral density in patients with primary hyperparathyroidism.

Cinacalcet is effective in controlling the biochemical abnormalities in patients with primary hyperparathyroidism (PHPT) but it seems to be less effective on bone mineral density (BMD). In the same patients, bisphosphonates are reported to be effective on bone resorption but less effective on calcium and PTH excess. In this study, the efficacy of cinacalcet in combination with alendronate has been retrospectively evaluated in patients with PHPT. Twenty-three patients with PHPT who had not been operated were retrospectively investigated. Cinacalcet was evaluated in combination with alendronate in 10 of the 23 patients, and in monotherapy in 13 other patients. Serum calcium, phosphorus and PTH, 24 h urine calcium and phosphorus as well as BMD, evaluated by DXA and expressed as T-score, were measured before and after treatment. In all patients serum calcium and phosphorus and urinary calcium excretion were effectively and stably controlled and PTH was significantly decreased after treatment. There was no difference in the rate of serum calcium and PTH decrease between subjects treated with cinacalcet plus alendronate and those treated with cinacalcet alone. T-score increased by 9.6% at lumbar spine and 3.9% at femur level in the cinacalcet plus alendronate subgroup and was unchanged in the cinacalcet subgroup (P < 0.01). In patients with PHPT, the biochemical abnormalities are rapidly improved by cinacalcet regardless from the administration in monotherapy or in combination with alendronate. BMD is significantly improved in patients receiving cinacalcet plus alendronate and stable in those receiving cinacalcet in monotherapy.

A decrease of calcitonin serum concentrations less than 50 percent 30 minutes after thyroid surgery suggests incomplete C-cell tumor tissue removal.

CONTEXT AND OBJECTIVES: The prognosis of medullary thyroid carcinoma (MTC) depends on the completeness of the first surgical treatment. To date, it is not possible to predict whether the tumor has been completely removed after surgery. The aim of this study was to evaluate the reliability of an intraoperative calcitonin monitoring as a predictor of the final outcome after surgery in patients with MTC. PATIENTS AND METHODS: Twenty patients underwent total thyroidectomy and central lymph node dissection on the basis of a positive pentagastrin test. In six cases a preoperative diagnosis of MTC was achieved at the cytological examination. During the surgical intervention, calcitonin was measured at the time of anesthesia, at the time of manipulation, and 10 and 30 min after surgical excision. At the histological examination, 10 patients had MTC and 10 had C cell hyperplasia. RESULTS: As compared with calcitonin levels before thyroidectomy, a decrease of calcitonin greater than 50% 30 min after surgery was able to significantly distinguish patients who were cured from those who experienced persistence of disease. It was not possible to find a similar result when the decrease of calcitonin 10 min after surgery was considered. CONCLUSIONS: A rate of calcitonin decrease less than 50% 30 min after thyroidectomy plus central neck lymph node dissection suggests the persistence of tumor tissue in patients operated for MTC. These results indicate that intraoperative calcitonin monitoring may be a useful tool to predict the completeness of surgery in patients with MTC.

Predictive value of pentagastrin test for preoperative differential diagnosis between C-cell hyperplasia and medullary thyroid carcinoma in patients with moderately elevated basal calcitonin levels.

BACKGROUND AND OBJECTIVES: Medullary thyroid carcinoma (MTC) is a calcitonin (CT)-secreting neuroendocrine tumour originating from thyroid C cells. Serum CT concentrations are helpful in the early detection of MTC, while it is still unclear whether they can be used also for the differential diagnosis between MTC and C-cell hyperplasia (CCH), a precancerous condition in familial MTCs but with unclear clinical significance in sporadic MTCs. Nowadays, surgery is recommended in all patients with basal or pentagastrin (PG)-stimulated CT value of 100 pg/ml or more, without discriminating if they are affected with MTC or CCH only. The objective of this study was to investigate the utility of the PG test for CT in distinguishing CCH from MTC before surgery. PATIENTS AND METHODS: Sixteen of 20 patients with thyroid nodules and basal CT levels between 15 and 100 ng/l had a positive PG test (>100 ng/l PG CT peak) and form the basis of the data analysis. A diagnosis of MTC was histologically proved on surgical samples in seven patients and of CCH in nine other patients. Four patients with neither FNAB nor PG test consistent with a diagnosis of MTC did not undergo thyroidectomy. RESULTS: A peak of CT of 275 ng/l after PG was able to significantly distinguish patients with MTC from patients with CCH, with 100% sensitivity and 89% specificity (P = 0.002). PG-stimulated calcitonin levels >275 ng/l had a positive predictive value (PPV) value for diagnosis of MTC of 100%, and PG-stimulated calcitonin levels <275 had a PPV for the diagnosis of CCH of 89%. CONCLUSIONS: A CT cut-off after PG of 275 ng/l is suggested to be highly predictive in distinguishing CCH from MTC before surgery, and this may be helpful in selecting patients for thyroid surgery.

Origin and distribution of the femoral nerve in fetuses of zebu-crossed bovines

In this study the femoral nerve origin and distribution was assessed through the dissection of 30 fetuses of zebu-crossed bovines, 20 males and 10 females. These animals samples fixation in 10% formaldehyde aqueous medium occurred either by subcutaneous, intra-muscle, and intra-cavity injections in different sites, or by immersion of the mentioned pieces in vessels containing the same medium. The femoral nerve originated from the forth (L4), fifth (L5), and sixth (L6) spinal lumbar ventral branches in 14 animals (46.7%), from L4 and L5 in 13 samples (43.3%), and L5 and L6 in three cases (10%). In the course of its way, on both antimeres the mentioned nerve was branched to the greater psoas (100%), iliac (100%), pectinal (56.7%), femoral quadriceps (100%), muscles, and gave off saphena nerve, which gave branches for the pectinal (43.3%) and sartorius (100%) muscles and continued distally along the saphena artery to spread on the medial face of the knee and leg medial articulation skin. Statistically, there was no significant difference between the muscle branch frequencies given by the femoral nerve to the right and left antimeres. The obtained results related to the femoral nerve origin and distribution in fetuses of zebu-crossed bovines generally presented common characteristics with the ruminant corresponding data found in the literature, and this information is important as the basis for clinical or surgical approaches involving the studied structures.

Traumatic lower extremity arteriovenous fistulae in children.

Traumatic arteriovenous fistulae are rare injuries in the pediatric population. Most are caused by penetrating injuries or are post-surgical in nature. Fistulae resulting from non-penetrating injuries are often missed early in the course of physical examination. This occurs due to the absence of clinical signs of arterial or venous injury, despite the close proximity of the affected vessels to point of injury. Likewise, signs and symptoms of post-surgical vascular injury may be difficult to discern from normal postoperative discomfort. The astute clinician must be on alert for unusual presentations of vascular injury to intervene in an expeditious manner. This article presents a series of vascular complications following either blunt injury or surgical management of the lower extremity in children who presented to our facility between November 2004 and December 2005.