Impact of climate change on the geographical distribution of ticks of public health significance in Colombia: Amblyomma ovale (Ixodida: Ixodidae), the Amblyomma maculatum (Ixodida: Ixodidae) complex and the Amblyomma cajennense (Ixodida: Ixodidae) complex.

Ticks of the Amblyomma maculatum (Ixodida Ixodidae) complex, the Amblyomma cajennense (Ixodida Ixodidae) complex and Amblyomma ovale (Ixodida Ixodidae) are known to transmit various Rickettsia species in Colombia, but their exact distribution is unknown. We built several models based on current climate and projected future climate changes using a maximum entropy approach. A total of 314 records of the A. cajennense complex (65.9%; n = 207), A. ovale (22.9%; n = 72), and the A. maculatum complex (11.1%; n = 35) were obtained. Amblyomma ovale has a current distribution in the Pacific, Caribbean and Andean regions and could be potentially found in the Amazon. Amblyomma maculatum has a current distribution in the Andean and could potentially be found in the Caribbean and Orinoco regions. Amblyomma mixtum can be found near the Caribbean Sea and in the Pacific region, and A. patinoi is likely to be found in the Andean region and the Caribbean. In 2070, it will be possible to find an expansion of A. ovale and A. maculatum and a decrease of A. mixtum and A. patinoi. The variables that best predict the distribution of these species are isothermality (small fluctuations in temperature) and annual precipitation. Amblyomma cajennense s.l and A. ovale, A. cajennese s.l and A. patinoi, as well as A. maculatum and A. patinoi, have an important environmental sympatry. Epidemiological and acarological surveillance is crucial to investigate rickettsiosis caused by R. parkeri in A. ovale regions, by R. rickettsii in A. patinoi and A. mixtum areas, and by R. parkeri s.s in A. maculatum regions.

Reappraisal of tacrolimus levels after liver transplant for HCC: A multicenter study toward personalized immunosuppression regimen.

Post-liver transplant (LT) immunosuppression is necessary to prevent rejection; however, a major consequence of this is tumor recurrence. Although recurrence is a concern after LT for patients with HCC, the oncologically optimal tacrolimus (FK) regimen is still unknown. This retrospective study included 1406 patients with HCC who underwent LT (2002-2019) at 4 US institutions using variable post-LT immunosuppression regimens. Receiver operating characteristic analyses were performed to investigate the influences of post-LT time-weighted average FK (TWA-FK) level on HCC recurrence. A competing risk analysis was employed to evaluate the prognostic influence of TWA-FK while adjusting for patient and tumor characteristics. The AUC for TWA-FK was greatest at 2 weeks (0.68), followed by 1 week (0.64) after LT. Importantly, this was consistently observed across the institutions despite immunosuppression regimen variability. In addition, the TWA-FK at 2 weeks was not associated with rejection within 6 months of LT. A competing risk regression analysis showed that TWA-FK at 2 weeks after LT is significantly associated with recurrence (HR: 1.31, 95% CI: 1.21-1.41, p < 0.001). The TWA-FK effect on recurrence varied depending on the exposure level and the individual's risk of recurrence, including vascular invasion and tumor morphology. Although previous studies have explored the influence of FK levels at 1-3 months after LT on HCC recurrence, this current study suggests that earlier time points and exposure levels must be evaluated. Each patient's oncological risk must also be considered in developing an individualized immunosuppression regimen.

Pan-lysyl oxidase inhibition disrupts fibroinflammatory tumor stroma, rendering cholangiocarcinoma susceptible to chemotherapy.

BACKGROUND: Cholangiocarcinoma (CCA) features highly desmoplastic stroma that promotes structural and functional resistance to therapy. Lysyl oxidases (LOX, LOXL1-4) catalyze collagen cross-linking, thereby increasing stromal rigidity and facilitating therapeutic resistance. Here, we evaluate the role of lysyl oxidases in stromal desmoplasia and the effects of pan-lysyl oxidase (pan-LOX) inhibition in CCA. METHODS: Resected CCA and normal liver specimens were analyzed from archival tissues. Spontaneous and orthotopic murine models of intrahepatic CCA (iCCA) were used to assess the impact of the pan-LOX inhibitor PXS-5505 in treatment and correlative studies. The functional role of pan-LOX inhibition was interrogated through in vivo and ex vivo assays. RESULTS: All 5 lysyl oxidases are upregulated in CCA and reduced lysyl oxidase expression is correlated with an improved prognosis in resected patients with CCA. Spontaneous and orthotopic murine models of intrahepatic cholangiocarcinoma upregulate all 5 lysyl oxidase isoforms. Pan-LOX inhibition reversed mechanical compression of tumor vasculature, resulting in improved chemotherapeutic penetrance and cytotoxic efficacy. The combination of chemotherapy with pan-LOX inhibition increased damage-associated molecular pattern release, which was associated with improved antitumor T-cell responses. Pan-LOX inhibition downregulated macrophage invasive signatures in vitro, rendering tumor-associated macrophages more susceptible to chemotherapy. Mice bearing orthotopic and spontaneously occurring intrahepatic cholangiocarcinoma tumors exhibited delayed tumor growth and improved survival following a combination of pan-LOX inhibition with chemotherapy. CONCLUSIONS: CCA upregulates all 5 lysyl oxidase isoforms, and pan-LOX inhibition reverses tumor-induced mechanical forces associated with chemotherapy resistance to improve chemotherapeutic efficacy and reprogram antitumor immune responses. Thus, combination therapy with pan-LOX inhibition represents an innovative therapeutic strategy in CCA.

Progression-Free Survival for Liver Transplant vs Alternative Therapy in Unresectable Colorectal Liver Metastasis.

This cohort study compares survival outcomes between patients with unresectable colorectal liver metastasis who received chemotherapy-based multimodal therapy and patients who underwent liver transplant.

Survival benefit of living donor liver transplant for patients with hepatocellular carcinoma.

With the increasing incidence of hepatocellular carcinoma (HCC) in both the United States and globally, the role of liver transplantation in management continues to be an area of active conversation as it is often considered the gold standard in the treatment of HCC. The use of living donor liver transplantation (LDLT) and the indications in the setting of malignancy, both generally and in HCC specifically, are frequently debated. In terms of both overall survival and recurrence-free survival, LDLT is at least equivalent to DDLT, especially when performed for disease within Milan criteria. Emerging and compelling evidence suggests that LDLT is superior to DDLT in treating HCC as there is a significant decrease in waitlist mortality. As the oncologic indications for liver transplantation continue to expand and the gap between organ demand and organ availability continues to worsen, high volumes centers should consider using LDLT to shrink the ever-expanding waitlist.

In Silico Study of Interactions between the Methylene Blue Molecule and the (TiO2)20 Cluster by Means of DFT Calculations.

In this work, the (TiO2)20 cluster is proposed to adsorb the methylene blue (BM) dye; thus, the quantum parameters to explain the adsorption process are calculated by means of density functional theory calculations. Eight possible configurations are obtained and labeled from M1 to M8. According to the adsorption energy values, they reveal physisorption for at least two cases, and for the rest of the systems, they exhibit chemisorption. The preferential positions that lead to good adsorption for the BM dye are parallel to the semiconductor cluster; however, when one end of the BM dye formed by hydrogen atoms is interacting with the cluster, a weak chemical interaction is reached. The chemical interactions for M4 and M5 systems generate considerable increases of their electronic gap values (E g) with respect to the rest, and this effect is explained based on iso-surfaces of frontier orbitals and electronic charge transference. The chemical interactions between these chemical species are stable under vibrational and thermal criteria. This semiconductor cluster arises as a good candidate to adsorb some dyes like BM.

First record of ectoparasites (Phthiraptera and Acari) from the Andean condor (Vultur gryphus) in Colombia.

Several species of ectoparasites, including chewing lice and mites are closely associated with their hosts. The Andean condor (Vultur gryphus) is globally listed as vulnerable by the IUCN and its population has been steadily declining in recent decades suggesting a potential extinction of associated entomofauna. The purpose of this study was to record the species of ectoparasites infesting three individuals of Andean condor found dead in the 'Páramo del Almorzadero' Santander Department, Northeastern Colombia. One juvenile (male) and two adults (male and female) Andean condors received for necropsy were carefully examined for ectoparasite infestation. Specimens were collected and preserved in ethanol (70%) for taxonomic studies. Morphologic identification and morphometric records were made under light microscopy. Some specimens were also prepared for scanning electron microscopy and others were subjected to DNA extraction to amplify and obtain sequences of the cytochrome-C oxidase subunit I (COI) gene for phylogenetic analyses. Lice were collected from the juvenile condor and the adult female and identified as Falcolipeurus assesor (Phthiraptera: Ischnocera) in the juvenile condor (8 females, 19 males and 8 nymphs) and the adult (1 female); Colpocephalum trichosum (Phthiraptera: Amblycera) in the juvenile (19 females, 24 males and 1 nymph) and the adult (2 females, 2 males and 3 nymphs); and Cuculiphilus zonatus (Phthiraptera: Amblycera) in the juvenile (40 females, 43 males and 15 nymphs) and the adult (1 male and 2 nymphs). Moreover, one mite collected from the juvenile condor was identified as Ancyralges cathartinus (Acari: Astigmata) (1 female). Morphometric data was obtained for the adult stages of F. assesor (6 females and 13 males), C. trichosum (9 females and 9 males) and C. zonatus (10 females and 10 males). We obtained the first DNA sequences of COI for F. assessor, and C. trichosum, where phylogenetic tree analysis showed that F. assessor is more closely related to Falcolipeurus marginalis, and C. trichosum to Colpocephalum kelloggi. This represents the first record of parasites in Andean condor from Colombia and contributes to the knowledge of chewing lice and mites associated with an endemic and endangered bird species. Further studies on Andean condor ectoparasites should be focused on documenting host-parasite interactions and potential health impacts in these wild birds.

Varias especies de ectoparásitos, incluidos piojos masticadores y ácaros están estrechamente asociados a sus hospedadores. El cóndor andino (Vultur gryphus) está catalogado por la UICN como una especie vulnerable y su población ha ido disminuyendo constantemente en las últimas décadas, lo que sugiere una posible extinción de la entomofauna asociada. El propósito de este estudio fue registrar las especies de ectoparásitos infestando a tres individuos de cóndor andino encontrados muertos en el Páramo del Almorzadero, Departamento de Santander, Noreste de Colombia. Un cóndor andino juvenil (macho) y dos adultos (macho y hembra) recibidos para necropsia fueron examinados cuidadosamente para detectar infestación por ectoparásitos. Los especímenes fueron recolectados y preservados en etanol (70%) para estudios taxonómicos. La identificación morfológica y los registros morfométricos se ejecutaron bajo microscopía óptica. Algunas muestras también se prepararon para microscopía electrónica de barrido y otras se sometieron a extracción de ADN para amplificar y obtener secuencias del gen de la subunidad I (COI) del citocromo­C oxidasa para análisis filogenéticos. Los piojos recolectados del cóndor juvenil y de la hembra adulta se identificaron como Falcolipeurus assesor (Phthiraptera: Ischnocera) en el cóndor juvenil (8 hembras, 19 machos y 8 ninfas) y en el adulto (1 hembra); Colpocephalum trichosum (Phthiraptera: Amblycera) en el juvenil (19 hembras, 24 machos y 1 ninfa) y en el adulto (2 hembras, 2 machos y 3 ninfas); y Cuculiphilus zonatus (Phthiraptera: Amblycera) en el juvenil (40 hembras, 43 machos y 15 ninfas) y en el adulto (1 macho y 2 ninfas). Además, un ácaro recolectado del cóndor juvenil fue identificado como Ancyralges cathartinus (Acari: Astigmata) (1 hembra). Se obtuvieron datos morfométricos para los estadios adultos de F. assesor (6 hembras y 13 machos), C. trichosum (9 hembras y 9 machos) y C. zonatus (10 hembras y 10 machos). Secuencias de ADN basadas en COI para las especies F. assesor y C. trichosum son reportadas por la primera vez, donde el análisis filogenetico mostró que F. assesor está más estrechamente relacionado con Falcolipeurus marginalis y C. trichosum con Colpocephalum kelloggi. Este representa el primer registro de parásitos en cóndor andino de Colombia y contribuye al conocimiento de los piojos masticadores y ácaros asociados a una especie de ave endémica de los Andes y en peligro de extinción. Otros estudios sobre los ectoparásitos del cóndor andino deberían centrarse en documentar las interacciones hospedador­parásito y los posibles impactos en la salud de estas aves silvestres.

Hyperparasitism in bat flies (Diptera: Streblidae): new records and interaction networks in the Neotropics.

Hyperparasitism is defined as the interaction where one parasite is infected by another parasite. In bat flies (Streblidae and Nycteribiidae), both hyperparasites and microparasites (bacteria, viruses, fungi, and arthropods such as mites) have been documented. Fungi belonging to the order Laboulbeniales are microscopic parasites of a wide diversity of arthropod hosts. Three genera exclusively target bat flies: Arthrorhynchus, which parasitizes species within Nycteribiidae in the Eastern Hemisphere, while genus Gloeandromyces and Nycteromyces parasitize Streblidae in the Western Hemisphere. Among the hyperparasitic arthropods, mites of family Neothrombidiidae, particularly the monospecific genus Monunguis, are known to parasitize bat flies. Here we present the first records of the hyperparasites Monunguis streblida and Gloeandromyces pageanus f. polymorphus parasitizing Streblidae bat flies in Colombia and a summary of these hyperparasitic interactions in the Neotropics. We detected fungi and mites parasitizing bat flies that were collected in the Magdalena River Basin, Colombia, in field expeditions in 2018, 2022, and 2023. We identified 17 bat flies and two species of hyperparasites, specifically M. streblida and the fungi Gloeandromyces. Our search for reports of these interactions in the Neotropics revealed that seven species of Trichobius (Streblidae) are parasitized by M. streblida, whereas Paratrichobius longicrus (Streblidae) is parasitized by Gloeandromyces pageanus f. polymorphus. These interactions have been reported in 11 countries, but our records are the first of M. streblida and Laboulbeniales fungi parasitizing bat flies in Colombia. So far, a total of 14 species of fungi and one species of mite have been associated with 19 species of bat flies, which in turn, are linked to 15 species of Neotropical bats.

Paraneoplastic leukocytosis secondary to carcinosarcoma: a report of two cases and literature review.

BACKGROUND: Neutrophilia is an increase in the number of neutrophils over 7.5×103/µL. An increase in leukocytes over 50×103/µL is called a leukemoid reaction; and when it is associated with a solid tumor, it is considered a paraneoplastic syndrome called paraneoplastic leukemoid reaction (PLR). It is a very rare clinical condition and it is very unusual for it to be associated with carcinosarcoma. We present two cases of a leukemoid reaction observed in the Medical Oncology Department of the University Hospital of Salamanca between May and September 2023. The main objectives of our article are to describe the unusual appearance of paraneoplastic leukocytosis at the diagnosis of carcinosarcoma carcinosarcoma, explain in a detailed way its diagnostic procedure and to show the poor prognosis to which it is associated. CASE DESCRIPTION: In our presentation, we describe two similar cases: first of all, a 60-year-old woman without relevant medical history. She was referred by her primary physician to the Department of Internal Medicine in August 2023 with asthenia, lumbar pain, and weight loss of 12 kg of 3 months of evolution. The physical examination revealed a palpable hypogastric mass. An abdominal, pelvic, and thoracic computed tomography (CT) scan revealed a heterogenous solid mass with necrotic areas originating in the uterus. The anatomopathological diagnosis was carcinosarcoma. The patient showed a progressive worsening in her renal function associated with hyperviscosity secondary to hyperleukocytosis caused by 170×103/µL neutrophils. In the second case we describe the diagnosis of a PLR secondary to a kidney carcinosarcoma. When the patient started chemotherapy, he presented 55.08×103/µL leukocytes, 53.16×103/µL neutrophils. Eight days after receiving chemotherapy, the patient was admitted as an emergency with oligoanuria and decreased consciousness. He presented creatinine 6.25 mg/dL, phosphate 12.4 mg/dL, leukocytes 1.05×103/µL, and neutrophils 0.71×103/µL. The clinical diagnosis was acute exacerbation of multifactorial mixed (renal and prerenal) chronic kidney disease associated with tumor lysis syndrome and grade 3 neutropenia. The patient presented a poor evolution, dying after 2 months. CONCLUSIONS: PLR is a severe paraneoplastic syndrome associated with different types of solid tumors. Its appearance at the time of diagnosis of a tumor implies a poor vital prognosis.

Harmonizing Definitions and Perspectives in Extreme Liver Surgery: A Delphi Experts Consensus.

OBJECTIVE: To propose to our community a common language about extreme liver surgery. BACKGROUND: The lack of a clear definition of extreme liver surgery prevents convincing comparisons of results among centers. METHODS: We used a two-round Delphi methodology to quantify consensus among liver surgery experts. For inclusion in the final recommendations, we established a consensus when the positive responses (agree and totally agree) exceeded 70%. The study steering group summarized and reported the recommendations. In general, a five-point Likert scale with a neutral central value was used, and in a few cases multiple choices. Results are displayed as numbers and percentages. RESULTS: A two-round Delphi study was completed by 38 expert surgeons in complex hepatobiliary surgery. The surgeon´s median age was 58 years old (52-63) and the median years of experience was 25 years (20-31). For the proposed definitions of total vascular occlusion, hepatic flow occlusion and inferior vein occlusion, the degree of agreement was 97%, 81% and 84%, respectively. In situ approach (64%) was the preferred, followed by ante situ (22%) and ex situ (14%). Autologous or cadaveric graft for hepatic artery or hepatic vein repair were the most recommended (89%). The use of veno-venous bypass or portocaval shunt revealed the divergence depending on the case. Overall, 75% of the experts agreed with the proposed definition for extreme liver surgery. CONCLUSION: Obtaining a consensus on the definition of extreme liver surgery is essential to guarantee the correct management of patients with highly complex hepatobiliary oncological disease. The management of candidates for extreme liver surgery involves comprehensive care ranging from adequate patient selection to the appropriate surgical strategy.

Cemented vs cementless stems for revision arthroplasties due to Vancouver B2 periprosthetic hip fracture.

PURPOSE: According to Vancouver classification, B2 type fractures are most often treated with removal of the loose stem and implantation of a long stem that bypasses the fracture site. However, there is a controversy about the stem fixation that should be used: cemented or cementless. Hence, this study aims to compare cemented and cementless stems in prosthetic revision due to Vancouver B2 (VB2) periprosthetic hip fracture. METHODS: A retrospective study was done including all the patients treated with stem exchange due to VB2 periprosthetic hip fracture in a tertiary hospital between 2015 and 2022. Patients were divided into two groups according to the stem fixation used: cemented or cementless. Functional outcomes, hospital stay, surgical time, complication rate, and mortality were compared between the two groups of patients. RESULTS: Of the 30 included patients, 13 (43.4%) were treated with cementless stems and 17 (56.7%) with cemented stems. There were no statistically significant differences in age, gender, anesthesia risk scale (ASA) or functional capacity prior to the intervention. Patients treated with cementless stems had a higher complication and reintervention rate than those treated with cemented stems: 62 and 45% versus 34 and 6% (p = 0.035; p = 0.010), respectively. Furthermore, in the group of cementless stems a higher proportion of non-union was found (53.8% vs. 17.6%; p = 0.037). Also, the hospital stay (33 vs. 24 days; p = 0.037) and the time to full weight-bearing (21 days vs. 9 days; p < 0.001) were longer in the cementless stem group. CONCLUSION: Cemented fixation in stem revision due to Vancouver B2 periprosthetic hip fracture could be an optimal option with faster recovery which could decrease the rate of complications and reintervention, without compromising the fracture healing and patient mortality. Thus, this option can be considered when an anatomical reduction can be obtained, especially in elderly patients with multiple comorbidities in which a less aggressive surgical option should be considered.

Deep convolutional neural network for weld defect classification in radiographic images.

The quality of welds is critical to the safety of structures in construction, so early detection of irregularities is crucial. Advances in machine vision inspection technologies, such as deep learning models, have improved the detection of weld defects. This paper presents a new CNN model based on ResNet50 to classify four types of weld defects in radiographic images: crack, pore, non-penetration, and no defect. Stratified cross-validation, data augmentation, and regularization were used to improve generalization and avoid over-fitting. The model was tested on three datasets, RIAWELC, GDXray, and a private dataset of low image quality, obtaining an accuracy of 98.75 %, 90.255 %, and 75.83 %, respectively. The model proposed in this paper achieves high accuracies on different datasets and constitutes a valuable tool to improve the efficiency and effectiveness of quality control processes in the welding industry. Moreover, experimental tests show that the proposed approach performs well on even low-resolution images.

Evaluation of digoxin-boronate ester formation through in-capillary derivatisation-large volume sample stacking-capillary zone electrophoresis.

Determination of digoxin through in-capillary derivatisation based on the formation of o-tolyl- and 2-naphthyl-anionic boronate esters in combination with large volume sample stacking-capillary electrophoresis is proposed. The derivatisation reaction was performed at basic pH values to obtain compounds with a charge and chromophore group during the stacking process. After stacking, the species were separated and detected at 225 nm using p-nitrophenol as an internal standard. Stacking and derivatisation parameters such as pre-concentration time, preconcentration voltage and injection time (relation between the analyte and the derivatisation agent) were evaluated using a Box-Behnken design. Under optimal conditions, the proposed method exhibits a linear range of 1.08-50.00 µM with a limit of detection of 0.36 µM; additionally, adequate repeatability and reproducibility was obtained (%RSD ≤ 5.0%). The methodology was validated by comparing it to an HPLC-UV established methodology and was successfully applied for the determination of digoxin in pharmaceutical tablets and blood serum samples, showing a positive performance for these matrices.

Vena cava replacement and major hepatectomy for liver tumors: international multicenter retrospective cohort study.

INTRODUCTION: Involvement of the inferior vena cava (IVC) and hepatic veins has been considered a relative contraindication to hepatic resection for primary and metastatic liver tumors. However, patients affected by tumors extending to the IVC have limited therapeutic options and suffer worsening of quality of life due to IVC compression. METHODS: Cases of primary and metastatic liver tumors with vena cava infiltration from 10 international centers were collected (7 European, 1 US, 2 Brazilian, 1 Indian) were collected. Inclusion criteria for the study were major liver resection with concomitant vena cava replacement. Clinical data and short-term outcomes were analyzed. RESULTS: Thirty-six cases were finally included in the study. Median tumor max size was 98 mm (range: 25-250). A biliary reconstruction was necessary in 28% of cases, while a vascular reconstruction other than vena cava in 34% of cases. Median operative time was 462 min (range: 230-750), with 750 median ml of estimated blood loss and a median of one pRBC transfused intraoperatively (range: 0-27). Median ICU stay was 4 days (range: 1-30) with overall in-hospital stay of 15 days (range: 3-46), postoperative CCI score of 20.9 (range: 0-100), 12% incidence of PHLF grade B-C. Five patients died in a 90-days interval from surgery, one due to heart failure, one due to septic shock, and three due to multiorgan failure. With a median follow-up of 17 months (interquartile range: 11-37), the estimated 5 years overall survival was 48% (95% CI: 27-66%), and 5-year cumulative incidence of tumor recurrence was 55% (95% CI: 33-73%). CONCLUSIONS: Major liver resections with vena cava replacement can be performed with satisfactory results in expert HPB centers. This surgical strategy represents a feasible alternative for otherwise unresectable lesions and is associated with favorable prognosis compared to nonoperative management, especially in patients affected by intrahepatic cholangiocarcinoma.

Machine learning regression algorithms to predict emissions from steam boilers.

Currently, the modeling of complex chemical-physical processes is drastically influencing industrial development. Therefore, the analysis and study of the combustion process of the boilers using machine learning (ML) techniques are vital to increase the efficiency with which this equipment operates and reduce the pollution load they contribute to the environment. This work aims to predict the emissions of CO, CO2, NOx, and the temperature of the exhaust gases of industrial boilers from real data. Different ML algorithms for regression analysis are discussed. The following are input variables: ambient temperature, working pressure, steam production, and the type of fuel used in around 20 industrial boilers. Each boiler's emission data was collected using a TESTO 350 Combustion Gas Analyzer. The modeling, with a machine learning approach using the Gradient Boosting Regression algorithm, showed better performance in the predictions made on the test data, outperforming all other models studied. It was achieved with predicted values showing a mean absolute error of 0.51 and a coefficient of determination of 99.80%. Different regression models (DNN, MLR, RFR, GBR) were compared to select the most optimal. Compared to models based on Linear Regression, the DNN model has better prediction performance. The proposed model provides a new method to predict CO2, CO, NOx emissions, and exhaust gas outlet temperature.

Vancouver B2 periprosthetic hip fractures treatment: fix or replace? A retrospective study comparing both techniques.

INTRODUCTION: Vancouver B2 periprosthetic hip fractures involve stem stability and they have been classically treated with revision surgery. Crucial factors such as age, clinical comorbidities and functional status are often neglected. The current study aims to compare clinical outcomes between patients treated with open reduction and internal fixation (ORIF) or femoral stem exchange. METHODS: This is a retrospective study that includes all Vancouver B2 periprosthetic hip fractures in a tertiary referral hospital from 2016 to 2020. Patients were divided into two groups: Group 1. Patients treated with an ORIF and Group 2. Patients treated with stem replacement. The outcomes that were compared between groups included demographic data, functional capacity, complications and mortality. RESULTS: 29 periprosthetic Vancouver B2 fractures were finally analyzed. 11 (37.9%) were treated with ORIF (Group 1) and 18 (62.1%) by stem replacement (Group 2). Surgery time (143 vs. 160 min), hemoglobin drop (1.8 vs. 2.5 g/dL) and hospital stance (25.5 vs. 29.6 days) were shorter in Group 1. According to complications, 18.2% of patients in the ORIF group had orthopedic complications compared with 44.4% in the revision group. In the revision group, 3 cases needed a two-stage revision and one of these revisions ended up with a resection arthroplasty (Girdlestone). The first-year mortality rate was 27% in Group 1 and 11% in Group 2. DISCUSSION: ORIF treatment seems to be a less aggressive and complex procedure which can lead to a faster general recovery. Revision surgery can imply a higher risk of orthopedic complications which can be severe and may require further aggressive solutions. The ORIF group mortality was similar to the proximal femur fracture rate (20-30%). In conclusion, ORIF treatment seems to be a good option especially in fragile patients with low functional demand when anatomical reduction is possible.