Assessing the Effect of the U.S. Vaccination Program on the Coronavirus Positivity Rate With a Multivariate Framework.

The factors influencing the incidence of COVID-19, including the impact of the vaccination programs, have been studied in the literature. Most studies focus on one or two factors, without considering their interactions, which is not enough to assess a vaccination program in a statistically robust manner. We examine the impact of the U.S. vaccination program on the SARS-CoV-2 positivity rate while simultaneously considering a large number of factors involved in the spread of the virus and the feedbacks among them. We consider the effects of the following sets of factors: socioeconomic factors, public policy factors, environmental factors, and non-observable factors. A time series Error Correction Model (ECM) was used to estimate the impact of the vaccination program at the national level on the positivity rate. Additionally, state-level ECMs with panel data were combined with machine learning techniques to assess the impact of the program and identify relevant factors to build the best-fitting models. We find that the vaccination program reduced the virus positivity rate. However, the program was partially undermined by a feedback loop in which increased vaccination led to increased mobility. Although some external factors reduced the positivity rate, the emergence of new variants increased the positivity rate. The positivity rate was associated with several forces acting simultaneously in opposite directions such as the number of vaccine doses administered and mobility. The existence of complex interactions, between the factors studied, implies that there is a need to combine different public policies to strengthen the impact of the vaccination program.

Caso clínico-radiológico: divertículo de Zenker / Clinical-radiological case: Zenker's diverticulum

Zenker's diverticulum develops in the hypopharynx, usually between the cricopharyngeus muscle and the inferior pharyngeal constrictor muscle, at the level of the C5 and C6 vertebrae. It often manifests clinically with dysphagia, persistent reflux, and halitosis. Its reference diagnosis is through barium video swallowing observed by fluoroscopy. Management is surgical with a cervical or transoral approach, the latter having a better safety profile

La contaminación citológica de la aguja de punción en ecobroncoscopia / Cytologic Contamination of the Sampling Needle in Endobronchial Ultrasound

No disponible

[Translated article] Cytologic Contamination of the Sampling Needle in Endobronchial Ultrasound / La contaminación citológica de la aguja de punción en ecobroncoscopia

No disponible

Obstructive lingual thyroid; suprahyoid intracervical surgical procedure - A case report. / Tiroides lingual obstructivo, intervención quirúrgica vía transcervical suprahioidea: reporte de un caso.

INTRODUCTION: The treatment of lingual thyroid is controversial and should be individualized. Options include hormonal replacement, surgery in the presence of bleeding and obstruction of the airway and the digestive tract, and radioisotope therapy. CLINICAL CASE: 8-year-old girl presenting with discomfort when swallowing. A pink, well-vascularized mass, not painful or ulcerated, protruding from the base of the tongue and virtually closing the whole oropharynx, was observed. Absence of thyroid tissue in its normal position was reported by the ultrasound department. Cervical computed axial tomography confirmed the diagnosis and the presence of pharyngeal obstruction. Thyroid hormone replacement was established. As a result of dysphagia symptom progression, surgery was indicated. Thyroid removal was performed by means of a cervicotomy, with re-implantation of thyroid tissue laminas. The postoperative course was uneventful and replacement treatment was maintained, with an excellent clinical status four years later.

INTRODUCCION: El tratamiento de la tiroides lingual es controvertido y debe individualizarse. Las opciones incluyen el reemplazo hormonal, cirugía en presencia de hemorragia y obstrucción de la vía aérea o digestiva, y la terapia con radioisótopos. CASO CLINICO: Niña de 8 años de edad, con molestias a la deglución. Se observa masa rosada, muy vascularizada, no dolorosa ni ulcerada, que protruye desde la base de la lengua y cierra prácticamente toda la orofaringe. Ecografía informa ausencia de tejido tiroideo en su posición normal. Tomografía axial computarizada cervical comprueba el diagnóstico y la obstrucción faríngea. Se indicó tratamiento sustitutivo de las hormonas tiroideas. Ante la progresión de los síntomas de disfagia, se indicó cirugía. Se describe la exéresis tiroidea por vía cervical, suprahioidea, con reimplante de láminas de tejido tiroideo. Evolucionó sin complicaciones y se mantiene tratamiento sustitutivo, con excelente estado clínico después de cuatro años.

Tiroides lingual obstructivo, intervención quirúrgica vía transcervical suprahioidea: reporte de un caso / Obstructive lingual thyroid; suprahyoid intracervical surgical procedure - A case report

Introducción: El tratamiento de la tiroides lingual es controvertido y debe individualizarse. Las opciones incluyen el reemplazo hormonal, cirugía en presencia de hemorragia y obstrucción de la vía aérea o digestiva, y la terapia con radioisótopos. Caso clínico: Niña de 8 años de edad, con molestias a la deglución. Se observa masa rosada, muy vascularizada, no dolorosa ni ulcerada, que protruye desde la base de la lengua y cierra prácticamente toda la orofaringe. Ecografía informa ausencia de tejido tiroideo en su posición normal. Tomografía axial computarizada cervical comprueba el diagnóstico y la obstrucción faríngea. Se indicó tratamiento sustitutivo de las hormonas tiroideas. Ante la progresión de los síntomas de disfagia, se indicó cirugía. Se describe la exéresis tiroidea por vía cervical, suprahioidea, con reimplante de láminas de tejido tiroideo. Evolucionó sin complicaciones y se mantiene tratamiento sustitutivo, con excelente estado clínico después de cuatro años

Introduction: The treatment of lingual thyroid is controversial and should be individualized. Options include hormonal replacement, surgery in the presence of bleeding and obstruction of the airway and the digestive tract, and radioisotope therapy. Clinical case: 8-year-old girl presenting with discomfort when swallowing. A pink, well-vascularized mass, not painful or ulcerated, protruding from the base of the tongue and virtually closing the whole oropharynx, was observed. Absence of thyroid tissue in its normal posi-tion was reported by the ultrasound department. Cervical computed axial tomography confirmed the diagnosis and the presence of pharyngeal ob-struction. Thyroid hormone replacement was established. As a result of dysphagia symptom progression, surgery was indicated. Thyroid removal was performed by means of a cervicotomy, with re-implantation of thyroid tissue laminas. The postoperative course was uneventful and replacement treatment was maintained, with an excellent clinical status four years later

Marcación de nódulos pulmonares con lipiodol bajo tomografía computada: experiencia local y correlación anatomopatológica / Marking of pulmonary nodules with lipiodol by computerized tomography: local experience and anatomopathological correlation

El objetivo de este estudio es la descripción de la novedosa y poco invasiva técnica de marcación de pequeños nódulos pulmonares con lipiodol, guiado con TAC para su posterior resección por cirugía videotoracoscópica con apoyo radioscópico. Se trata de un estudio retrospectivo que incluye 51 pacientes consecutivos en un tiempo comprendido entre junio del 2012 a septiembre del 2017, obteniendo el diagnóstico final mediante la correlación anatomopatológica, representando los procesos malignos el 81% y los benignos el 19%. Mediante esta técnica se lograron identificar y extraer con éxito el 100% de los nódulos marcados, demostrándose la efectividad y seguridad del procedimiento por las mínimas complicaciones relacionadas.

The purpose of this study is describing a novel and minimally invasive technique of CT-guided marking of small pulmonary nodules with lipiodol prior to resection by videothoracoscopic surgery with radioscopic support. This is a retrospective study that includes 51 consecutive patients between June 2012 and September 2017, with the final diagnosis confirmed by pathology. Malignant nodules represented 81% of the cases with the remaining 19% being benign nodules. Through this technique, 100% of the marked nodules were successfully identified and extracted with few procedure related complications and no adverse clinical outcome, demonstrating the effectiveness and safety of the procedure.

Rendezvous technique for the treatment of complete common bile duct transection after multiple hepatobiliary surgeries.

Common bile duct (CBD) injury during surgical procedures is a serious complication. Partial injury can usually be managed by a combination of percutaneous and/or endoscopic techniques. However, the management of complete transection of the CBD is very challenging. There are small case series of nonsurgical management of complete CBD transection during laparoscopic cholecystectomy. In this particular case, a 55-year-old female patient had multiple operations because of malignant pheochromocytoma with liver metastases. She developed a complete CBD transection during right hepatectomy. A biloma was managed with image-guided percutaneous drainage. However, both attempts of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) for CBD stent were unsuccessful, as the native CBD was partially resected during the injury. A rendezvous procedure, in which a guidewire was placed through the distal CBD and into a biloma by ERCP and subsequently snared with PTC, allowed for a biliary-duodenal catheter to be placed successfully and achieve continuity of the patient's biliary tree.

Representativeness of nodal sampling with endobronchial ultrasonography in non-small-cell lung cancer staging.

The objective of our study was to determine the procedure-related requirements of mediastinal node sampling with endobronchial ultrasonography with real-time transbronchial needle aspiration (EBUS-TBNA) that would provide negative predictive value (NPV) for the identification of stage III disease in non-small-cell lung cancer (NSCLC) high enough to consider the technique equivalent to cervical mediastinoscopy. Representative EBUS-TBNA was defined as a sampling procedure obtaining satisfactory samples from normal nodes in regions 4R, 4L and 7 or diagnosing malignancy in mediastinal nodes. NPV was estimated using the results of postsurgical staging in patients who underwent surgery as a reference. Two-hundred ninety-six patients staged with EBUS-TBNA were included. Representative samples from regions 4R, 4L and 7 showing nonmalignant cytology were obtained from 98 patients (33.1%) and EBUS-TBNA detected N2/N3 disease in 150 (50.7%). Accordingly, an EBUS-TBNA procedure accomplishing the representativeness criteria required for sampling was attained in 248 of the participating patients (83.8%). The NPV of the procedure in this setting was 93.6%, with false-negative results only found in 5 patients, four of them with nodal metastasis out of the reach of EBUS-TBNA (regions 5, 8 and 9). In conclusion, representative sampling of regions 4R, 4L and 7 is achieved in more than 80% of patients staged using EBUS-TBNA, and in the procedures that attain this requirement a NPV >90% for mediastinal malignancy is reached, a figure equivalent to cervical mediastinoscopy.

In search of the best peritoneal adhesion model: comparison of different techniques in a rat model.

BACKGROUND: Adhesion-related complications after abdominal surgery result in significant morbidity and costs. Results from animal studies investigating prevention or treatment of adhesions are limited due to lack of consistency in existing animal models. The aim of this study was to compare quality and quantity of adhesions in four different models and to find the best model. MATERIALS AND METHODS: This study was approved by the University of Missouri Animal Care and Use Committee (ACUC). Forty female rats were randomly assigned to four different groups of 10 animals each. Adhesion created was performed utilizing the four techniques: Group 1 - parietal peritoneum excision (PPE), Group 2 - parietal peritoneum abrasion (PPA), Group 3 - peritoneal button creation (PBC), and Group 4 - cecal abrasion (CA). Rats were allowed to recover and necropsy was performed on postoperative d 14. Adhesions were scored by an established quantitative and qualitative scoring systems. The midline incision served as the control in each animal. RESULTS: The four groups were not equal with respect to both quantity score (P<0.001) and quality score (P=0.042). The PBC group had the highest quantity of adhesions. The highest quality of adhesion was seen in the PPE group. A multivariate analysis carried out to quantify the performance of each model clearly demonstrated that PBC exhibited the best results in terms of both quantity and quality. CONCLUSIONS: The button technique (PBC) is most consistent and reproducible technique for an intra-abdominal adhesion model. This model can help in the study and development of substances to prevent adhesion formation in the future.

Transvaginal repair of a large chronic porcine ventral hernia with synthetic mesh using NOTES.

BACKGROUND: Ventral incisional hernias still remain a common surgical problem. We tested the feasibility of transvaginal placement of a large synthetic mesh to repair a porcine hernia. METHODS: Seven pigs were used in this survival model. Each animal had creation of a 5-cm hernia defect and underwent a transvaginal repair of the defect with synthetic mesh. A single colpotomy was made using a 12-cm trocar for an overtube. The mesh was cut to size and placed through the trocar. A single-channel gastroscope with an endoscopic atraumatic grasper was used for grasping sutures. Further fascial sutures were placed every 5 cm. RESULTS: Mesh repair was feasible in all 7 animals. Mean operative time was 133 minutes. Technical difficulties were encountered. No gross contamination was seen at the time of necropsy. However, 5 animals had positive mesh cultures; 7 had positive cultures in the rectouterine space in enrichment broth or on direct culture. CONCLUSION: Transvaginal placement of synthetic mesh to repair a large porcine hernia using NOTES is challenging but feasible. Future studies need to be conducted to develop better techniques and determine the significance of mesh contamination.

Characterization of bacteria using its O-antigen with surface-enhanced Raman scattering.

The O-antigen determines the specificity of bacterial serotype, a sort of bacterial fingerprinting. In this work we report the extraction, purification and characterization of the O-antigen of two pathogenic bacteria, Escherichia coli O16 and Salmonella typhimurium. Molecular fingerprints found in the vibrational spectra represent a powerful analytical technique for identification (or differentiation) of molecular moieties in complex systems such as pathogens. In addition, advantages of vibrational Raman scattering are unique thanks to the high sensitivity and specificity achieved via surface-enhanced Raman scattering (SERS). SERS is used here to take advantage of characteristic vibrational frequency differences of O-antigens, thus allowing bacterial differentiation. Characteristic fundamental vibrational modes associated with the monosaccharide N-acetylglucosamine and deformations of the O-antigen chains provide the main spectroscopic differences between the O-antigens of E. coli O16 and S.typhimurium.

Pilot data on the endoscopic placement of covered metal stents to treat gastrojejunal leaks in a porcine model.

BACKGROUND: Placement of stents may be an alternative option to treat gastrojejunal (GJ) anastomotic leaks after Roux-en-Y gastric bypass (RYGB) surgery. The aim was to evaluate the performance of a covered metal stent (Alimaxx-E, 18 x 100 mm) across a GJ leak in a porcine model. METHODS: In eight pigs, a RYGB was performed and a 1-cm leak was created. A retrogastric and anterogastric GJ was performed equally with four pigs in each group. Stents were placed across the GJ anastomosis using endoscopy and fluoroscopy. The endpoints were position of the stents, healing of the leak, and complications at necropsy. RESULTS: Stent placement was feasible in all pigs it was attempted. In the retrogastric GJ group, pigs without stents survived 2 weeks without complications. Two pigs with stents died on postoperative days (PODs) 4 and 5. In the anterogastric GJ group, one pig with one stent survived 2 weeks with healing of the leak but with stent migration into the Roux limb. The remaining three pigs died between PODs 4 and 6. Pressure necrosis of the Roux limb caused by the distal end of the stent was found in all. CONCLUSIONS: Placement of fully covered metal stents is feasible. The use of small pigs with a thin small bowel wall in combination with relatively large stents was most likely the reason for complications found in all stented animals. Further studies of GJ leaks using these stents will require larger pigs or a different species.

Transgastric biologic mesh delivery and abdominal wall hernia repair in a porcine model.

BACKGROUND AND STUDY AIMS: Incisional abdominal wall hernias currently require repair with open or laparoscopic surgery, which is associated with wound complications and recurrent hernia formation. Natural orifice transluminal endoscopic surgery (NOTES) techniques may have the potential to decrease the morbidity associated with hernia repair. The aim of this study was to repair a chronic ventral hernia with a biologic mesh placed transgastrically in a porcine model. MATERIALS AND METHODS: Six pigs underwent creation of an incisional abdominal wall hernia. At least 4 weeks later, transgastric repair was done using an underlay biologic mesh with at least 5 cm of overlap from the hernia fascial edge. The mesh was secured with transfascial sutures and the stomach was closed with a sutured gastropexy. Pigs were evaluated 2 weeks later by laparoscopy. Pigs were sacrificed and necropsy wa s performed 4 weeks after the repair. RESULTS: Six pigs underwent hernia repair lasting a mean (+/- SD) of 204 +/- 123 minutes, with one perioperative death. At 2 weeks after hernia repair, laparoscopy showed significant adhesions in all pigs; one pig had extensive mesh infection and was sacrificed. Necropsy on one pig at 2 weeks and four pigs at 4 weeks showed complete coverage of the hernia defect in all pigs. All pigs had mesh abscesses or a positive mesh culture. CONCLUSION: Transgastric repair of a chronic ventral hernia is technically feasible. Difficulties with mesh delivery and infection need to be overcome before this approach can be used in humans.

Transgastric placement of biologic mesh to the anterior abdominal wall.

BACKGROUND: Incisional hernia repairs have a risk of wound complications that may be decreased using a natural orifice transluminal endoscopic surgery (NOTES) approach. The aim of this study was to determine the feasibility and safety of transgastric mesh placement to the anterior abdominal wall in a porcine model as a precursor to future studies of NOTES ventral hernia repair. METHODS: The procedure was done under sterile conditions with a double lumen endoscope using a plastic overtube. The endoscope was placed in the stomach preloaded with an overtube. Entrance of the endoscope and overtube into the peritoneal cavity was performed with the percutaneous endoscopic gastrostomy (PEG) technique. A 13 x 15 cm Surgisis Gold mesh with four corner sutures was delivered through the overtube. Transfascial suture passer and endoscopic grasper were used to externalize the sutures and attach the mesh to the anterior abdominal wall. The gastrotomy was closed with a transabdominal gastropexy. The pigs were sacrificed at 2 weeks. RESULTS: Mesh placement was performed in five pigs. Operative time was 215 min (standard deviation, SD 99 min). The most difficult portion of the procedure involved manipulating the gastric overtube, likely exposing the mesh to bacteria in the stomach. Culture-positive abscesses were present at the mesh in 3/5 animals. The mesh appeared intact in 4/5 animals; one of the infected meshes had delamination of 50% of the mesh. Adhesions to the mesh surface varied from 2% to 100%. At 2 weeks, median mesh size was 116 cm2 (range 96-166 cm2) and median contraction was 41% (range 15-51%). Histologic evaluations demonstrated marked inflammation and fibrosis progressing into the mesh material. CONCLUSIONS: Totally endoscopic transgastric delivery and fixation of a biologic mesh to the anterior abdominal wall is feasible. Challenges remain in designing systems for mesh delivery that exclude gastric content. Once these problems can be surmounted NOTES ventral hernia repair may become an option in man.

Laparoscopic appendectomy--is it worth the cost? Trend analysis in the US from 2000 to 2005.

BACKGROUND: Although laparoscopic appendectomy is widely used for treatment of appendicitis, it is still unclear if it is superior to the open approach. STUDY DESIGN: From the Nationwide Inpatient Sample 2000 to 2005, hospitalizations with the primary ICD-9 procedure code of laparoscopic (LA) and open appendectomy (OA) were included in this study. Outcomes of length of stay, costs, and complications were assessed by stratified analysis for uncomplicated and complicated appendicitis (perforation or abscess). Regression methods were used to adjust for covariates and to detect trends. Costs were rescaled using the hospital and related services portion of the Medical Consumer Price Index. RESULTS: Between 2000 and 2005, 132,663 (56.3%) patients underwent OA and 102,810 (43.7%) had LA. Frequency of LA increased from 32.2% to 58.0% (p < 0.001); conversion rates decreased from 9.9% to 6.9% (p < 0.001). Covariate adjusted length of stay for LA was approximately 15% shorter than for OA in both uncomplicated and complicated cases (p < 0.001). Adjusted costs for LA were 22% higher in uncomplicated appendicitis and 9% higher in patients with complicated appendicitis (p < 0.001). Costs and length of stay decreased over time in OA and LA. The risk for a complication was higher in the LA group (p < 0.05, odds ratio=1.07, 95% CI 1.00 to 1.14) with uncomplicated appendicitis. CONCLUSIONS: LA results in higher costs and increased morbidity for patients with uncomplicated appendicitis. Nevertheless, LA is increasingly used. Patients undergoing LA benefit from a slightly shorter hospital stay. In general, open appendectomy may be the preferred approach for patients with acute appendicitis, with indication for LA in selected subgroups of patients.

Colonic sterilization for natural orifice translumenal endoscopic surgery (NOTES) procedures: a comparison of two decontamination protocols.

BACKGROUND: This study aimed to evaluate the effect of two different sterilization protocols on the bacterial counts in the swine colon as preparation for natural orifice translumenal endoscopic surgery (NOTES) surgery. METHODS: In this study, 16 swine were randomized to two different colonic sterilization protocols: low colonic irrigation using 300 ml of a 1:1 dilution of 10% povidone-iodine (Betadine) with sterile saline, followed by 1 g of cefoxitin dissolved in 300 ml of saline or two consecutive 300-ml irrigations using a quaternary ammonium antimicrobial agent (Onamer M). Colonic cultures were taken before colonic cleansing after a decontamination protocol and after completion of the NOTES procedure. The Invitrogen live/dead bacterial viability kit was used to assess for change in the bacterial load. A qualitative culture of peritoneal fluid was obtained at the end of the NOTES procedure. Colon mucosal biopsies obtained immediately after the sterilization procedure and at the 2-week necropsy point were evaluated for mucosal changes. RESULTS: Protocol 1 resulted in an average 93% decrease in live colonic bacteria versus 90% with protocol 2 (nonsignificant difference). After a NOTES procedure, group 1 had a 62% increase in live bacteria and group 2 had a 31% increase (nonsignificant difference). Peritoneal cultures also were obtained. Bacteria were isolated from the peritoneal fluid of all the animals, and two or more species were isolated from 75% of the animals. There was no evidence of peritoneal infection at necropsy. Reactive epithelial changes and mild inflammation were the only pathologic abnormalities. No changes were noted at histologic evaluation of colonic mucosa after 2 weeks, demonstrating that these were temporary changes. CONCLUSION: Colonic irrigation with Betadine and antibiotics are as effective for bacterial decontamination of the swine colon as a quaternary ammonium compound. The results of this study support the use of either protocol. Despite thorough decontamination, peritoneal contamination occurs. The significance of this for humans is unknown.

Laparoscopic Nissen fundoplication is a good option in patients with abnormal esophageal motility.

BACKGROUND: Patients with gastroesophageal reflux disease (GERD) and abnormal esophageal motility are the most controversial subgroup of surgically treated patients because of potentially increased risk of postoperative dysphagia. Our study aim was to determine if Nissen fundoplication is associated with increased postoperative dysphagia in patients with ineffective esophageal motility. METHODS: Medical records of all adult (>18 years old) patients who underwent laparoscopic Nissen fundoplication for GERD over 8 years were reviewed retrospectively. Of the 151 patients, 28 (group A) met manometric criteria for abnormal esophageal motility (<30 mmHg mean contractile pressure or <80% peristalsis), whereas 63 (group B) had normal esophageal function. Sixty patients had no manometric data and were therefore excluded from analysis. Follow-up time ranged from 1 month to 5 years. Outcomes (postoperative dysphagia, recurrence of GERD symptoms, free of medications) were compared between groups. RESULTS: Group A had higher age and American Society of Anesthesiologists (ASA) score (p = 0.016 and 0.020), but this did not correlate with outcome. Two patients (7.1%) in group A and three patients (5.3%) in group B had postoperative dysphagia. When adjusted for follow-up time, there was no significant difference between the groups (p = 0.94). Group B had more cases of recurrent heartburn (10.7% versus 3.6%, p = 0.039), and more patients in this group were back on medications (21.4% versus 7.1%, p < 0.05) CONCLUSIONS: This retrospective study found equally low rates of dysphagia following Nissen fundoplication regardless of baseline esophageal motility. Preoperative esophageal dysmotility therefore does not seem to be a contraindication for laparoscopic Nissen fundoplication.