Clinical Characteristics and Outcome of Pneumomediastinum in Patients with COVID-19 Pneumonia.

Introduction: Pneumomediastinum (PM) is characterized by the presence of air within the mediastinum. The association between PM and coronavirus 2019 (COVID-19) has not been well established in the current literature. We sought to summarize the limited body of literature regarding PM in patients with COVID-19 and characterize the presentation and clinical outcomes of PM in patients with severe acute respiratory syndrome (SARS)-COV-2 pneumonia at our institution to better define the incidence, prognosis, and available treatment for this condition. Materials and Methods: All patients with a proven diagnosis of COVID-19 and PM between March 18, 2020 and May 5, 2020 were identified through hospital records. Retrospective analysis of radiology records and chart review were conducted. Clinical characteristics and outcomes were collected and descriptive statistics was analyzed. Results: Thirty-six patients met inclusion criteria. Out of the 346 intubated COVID-19 patients, 34 (10%) had PM. The incidence of PM increased for the first 4 weeks of the pandemic, and then began to decrease by week 5. At the endpoint of the study, 12 (33.33%) patients were alive and 24 patients (66.67%) had died. Conclusion: PM, although a rare phenomenon, was more prevalent in COVID-19 patients compared with historical patients with adult respiratory distress syndrome. The etiology of this condition may be attributed to higher susceptibility of patients infected with SARS-CoV-2 to a combination of barotrauma and airway injury.

Localized Bathless Metal-Composite Plating via Electrostamping.

Composite plating with particles embedded into the metal matrix can enhance the properties of the metal coating to make it more or less conductive, hard, durable, lubricated or fluorescent. However, it can be more challenging than metal plating, because the composite particles are either 1) not charged so they do not have a strong electrostatic attraction to the cathode, 2) are hygroscopic and are blocked by a hydration shell, or 3) too large to remain stagnate at the cathode while stirring. Here, we describe the details of a bathless plating method that involves anode and cathode nickel plates sandwiching an aqueous concentrated electrolyte paste containing large hygroscopic phosphorescent particles and a hydrophilic membrane. After applying a potential, the nickel metal is deposited around the stagnant phosphor particles, trapping them in the film. The composite coatings are characterized by optical microscopy for film roughness, thickness and composite surface loading. In addition, fluorescence spectroscopy can be used to quantify the illumination brightness of these films to assess the effects of various current densities, coating duration and phosphor loading.

The Use of Fluorescence Imaging in Colon Interposition for Esophageal Replacement: A Technical Note.

Every field of surgery has seen an explosion of new technologies aimed at improving surgical technique and reducing complications. The use of near-infrared (NIR) fluorescence to assess perfusion has been described in several surgical disciplines. NIR provides the surgeon with real-time perfusion assessment of a target organ or anastomosis and can be invaluable in aiding decision-making during the index operation. In the following article we discuss the use of fluorescence-guided perfusion assessment during colonic interposition for esophageal replacement. To our knowledge this is the first description of the use of fluorescence-guided perfusion assessment during colonic interposition.

Simultaneous unilateral anterior thoracoscopy with transcervical thyroidectomy for the resection of large mediastinal thyroid goiter.

BACKGROUND: Almost 25% of thyroid goiters have an intrathoracic component. Although the majority of mediastinal goiters may be approached through a cervical approach, up to a third of substernal goiters require a sternotomy or thoracotomy for resection. As an alternative to conventional sternotomy, we herein describe a combined anterior thoracoscopic and transcervical approach to large mediastinal thyroid goiters. METHODS: Between 2012 and 2015, seven patients with symptomatic thyroid goiters with significant intrathoracic extension were approached via simultaneous cervical exploration and anterior thoracoscopy. Thoracoscopy was performed on the side of maximal goiter extension. RESULTS: Simultaneous thoracoscopy and transcervical thyroidectomy was technically successful in all patients. No patients required conversion to open approach and one patient required reoperation for hemorrhage. CONCLUSIONS: Simultaneous anterior thoracoscopy and cervical exploration is a safe and effective approach to large mediastinal thyroid goiter. Patients with significant intrathoracic goiter extension may benefit from preoperative thoracic surgical evaluation and planned thoracoscopy at the time of thyroidectomy.

Subdiaphragmatic bronchogenic cyst at the gastroesophageal junction presenting with Dysphagia: a case report.

BACKGROUND: Bronchogenic cysts are benign lesions derived from the primitive foregut. They frequently occur in the mediastinum, most commonly at the subcarinal level. Subdiaphragmatic location for bronchogenic cysts is extremely rare. METHODS: A 40-year-old woman presented with worsening dysphagia and was diagnosed as a bronchogenic cyst arising from infradiaphragmatic esophagus by computed tomographic scan and endoscopic ultrasound-guided aspiration. Total laparoscopic enucleation of the cystic mass was performed. RESULTS: The postoperative esophagogram revealed no leak or reflux and the patient was discharged on day 2. The histopathologic examination revealed a bronchogenic cyst. No recurrence of the cyst or symptoms was noted at 6 months. CONCLUSIONS: Infradiaphragmatic bronchogenic cysts are uncommon and may become symptomatic secondary to compression of surrounding structures. A complete resection by laparoscopy is feasible and represents a safe and minimally invasive alternative to traditional resection through laparotomy or thoracotomy.

Surgery for other pulmonary fungal infections, Actinomyces, and Nocardia.

Surgical participation in the management of fungal infections has changed since the advent of effective antimicrobials. Even so, a surgeon may be called on for a variety of reasons, depending on the specific fungal infection and the evolution of thoracic disease. Specific fungal infections are enumerated. Each organism, its clinical picture, and method of diagnosis are briefly described and the medical and surgical management of thoracic disease are discussed.

Traction esophageal diverticulum: a rare cause of gastro-intestinal bleeding.

Esophageal diverticula are uncommon lesions that are usually classified according to their location (cervical, thoracic, or epiphrenic), or underlying pathogenesis (pulsion or traction), and their morphology (true or false).The majority of esophageal diverticula are acquired lesions that occur predominantly in elderly adults. Pulsion, or false, diverticula are the most commonly encountered type of esophageal diverticula noticed at the level of cricopharyngeus muscle, occur as a localized outpouchings that lacks a muscular coat, and as such their wall is formed entirely by mucosa and submucosa. True, or traction, esophageal diverticulum (TED) is seen in the middle one third of the thoracic esophagus in a peribronchial location, occurs secondary to mediastinal inflammatory lesions such as tuberculosis or histoplasmosis. The resultant desmoplastic reaction in the paraesophageal tissue causes full thickness pinching on the esophageal wall, producing a conical, broad-mouthed true diverticulum. They often project to the right side because subcarinal lymph nodes in this area are closely associated with the right anterior wall of the esophagus. TED usually presents with symptoms such as dysphagia, postural regurgitation, belching, retrosternal pain, heartburn, and epigastric pain. As in patients with pharyngoesophageal (Zenker's) diverticula, pulmonary symptoms are often present but underestimated in TED patients. These symptoms range from mild nocturnal cough to life-threatening massive aspiration. In this particular report we describe a rare case of TED presenting as a symptomatic upper gastrointestinal bleeding. Diagnostic evaluation of TED includes chest X-ray, barium esophagogram and manometry. A significant proportion of lower esophageal diverticula are associated with motility disorders. Management of TED include treating the underlying cause sometimes a surgical resection of diverticulum along with esophageal myotomy is necessitated in symptomatic patients.

Pseudocavitating bronchioloalveolar carcinoma followed over a decade.

A 38-year-old woman with bronchioloalveolar carcinoma (BAC) had a slow-growing cavitary nodule for nearly a decade. When she was hospitalized because of pneumonia 9 years earlier, a chest computed tomography scan showed a 1.5-cm cavitary right upper lobe nodule. At 1, 3, and 9 years computed tomography scans showed slow growth of the nodule to 2.4 cm, corresponding to a volume doubling time of 1494 days. Thoracoscopic biopsy and lobectomy were performed. Pathologic analysis revealed a well-differentiated mucinous BAC (T1N0M0). Pseudocavitation in solitary BAC is rare. A longer period of surveillance may be required to rule out malignancy in this setting. Surgical resection remains the mainstay of therapy.

Video-assisted thoracoscopic lobectomy: state of the art and future directions.

BACKGROUND: Thoracoscopic lobectomy is performed with increasing frequency for early-stage lung cancer. Several published reports suggest thoracoscopic resection is safe, with the potential advantage of shorter hospital stay, quicker recovery, and comparable oncologic results. METHODS: Data on 180 video-assisted thoracoscopic surgery (VATS) patients who underwent thoracoscopic lobectomy or sublobar anatomic resection at our institution between January 2002 and December 2006 were reviewed. The conversion rate to thoracotomy, complications, length of stay, and duration of chest tube drainage were determined. Similar variables were evaluated for patients aged older than 80 years, those with a forced expiratory volume in 1 second (FEV1) that was less than 50% predicted, those who had undergone preoperative neoadjuvant therapy, and those who had undergone lung-sparing anatomic resections. RESULTS: Thoracoscopic anatomic lung resection was performed successfully in 166 patients. One of 180 patients (0.6%) died, and 14 patients (9.2%) underwent conversions. Overall median length of stay was 4 days (range, 1 to 98; interquartile range [IQR], 3), and median duration of chest tube drainage was 3 days (range, 0 to 35 days; IQR, 2). The median length of hospital stay and median chest tube duration for the group aged 80 years and older was 5 and 3 days; for the segmental resection group, 4 and 3 days; for the chemotherapy or radiotherapy induction group, 3.5 and 3 days; and for the FEV1 less than 50% group, 5.5 and 4 days, respectively. No patients died in any of these groups. CONCLUSIONS: Thoracoscopic lung resection can be performed safely in selected patients aged 80 years and older, in those with marginal pulmonary function, and in those with pathologic response to neoadjuvant therapy.

Adenosine A(2A) receptor activation promotes wound neovascularization by stimulating angiogenesis and vasculogenesis.

Recent reports indicate that circulating endothelial progenitor cells (EPCs) may be recruited to sites of neovascularization where they differentiate into endothelial cells (EC). As we have previously demonstrated that adenosine A(2A) agonists promote neovascularization in wounds, we sought to determine whether adenosine A(2A) receptor agonist-augmented wound healing involves vessel sprouting (angiogenesis) or EPC recruitment (vasculogenesis) or both. Four weeks after bone marrow reconstitution from donor FVB/N Tie2GFP transgenic mice, two full-thickness excisional wounds were performed on the dorsum of FVB/N wild-type mice and treated with either an A(2A) receptor agonist (CGS-21680) or vehicle alone. Vessel density, as measured by CD31 staining, and density of EPC-derived vessels, as measured by GFP expression, were quantified in a blinded fashion using two-color fluorescence microscopy. We observed nearly a threefold increase in CD31-positive vessels and a more than 10-fold increase in GFP-positive cells in A(2A) agonist-treated 3-day old wounds, but by 6 days after wounding the differences between A(2A) agonist-treated and vehicle-treated wounds were no longer statistically significant. In conclusion, this is the first evidence that an exogenous agent such as an adenosine A(2A) receptor agonist increases neovascularization in the early stages of wound repair by increasing both EPC recruitment (vasculogenesis) and local vessel sprouting (angiogenesis).

Experimental hindlimb ischemia leads to neutrophil-mediated increases in gastrocnemius MMP-2 and -9 activity: a potential mechanism for ischemia induced MMP activation.

INTRODUCTION: Matrix metalloproteinases (MMP)-2 and -9 are Type 4 collagenases instrumental in basement membrane degradation, a process necessary for angiogenesis to occur. Polymorphonuclear leukocytes (PMNs) contain MMP-9, and in the presence of both PMN-derived serine protease and membrane type 1 (MT1)-MMP, are able to activate pro-MMP-2 following hindlimb ischemia. We hypothesized that neutrophil depletion (ND) of animals prior to hindlimb ischemia (HI) would abrogate the activation of pro-MMP-2 and decrease the level of MMP-9 MATERIALS AND METHODS: 12 FVB/N Tie2/LacZ-182 SATO female mice were randomly divided into four blinded groups; HI + PBS, HI + anti-PMN antibody (GR-1), HI + isotype matched control antibody (IgG(2b,K)), and no HI + PBS. PMN depletion was achieved prior to the time of ischemia and maintained until sacrifice. HI was achieved by unilateral femoral artery ligation. Three days postligation the animals were sacrificed and the gastrocnemius muscle from each hindlimb was harvested. MMP-2 and -9 (gelatin zymography) and MT1-MMP (Western blot) expression and activation were quantified by densitometry and NIH Image Analysis software. MMP values were expressed as a ratio of ischemic-to-nonischemic hindlimbs and compared between groups. Statistical significance was determined with analysis of variance (ANOVA) RESULTS: Zymograms revealed a greater than 10-fold increase in active MMP-9 and greater than 4-fold increase in active MMP-2 from HI + PBS compared to no HI + PBS (P < 0.05). HI + anti-PMN antibody demonstrated reduction of both active MMP-2 and -9 levels to that of the nonischemic group. Pro-MMP-2 was constitutively expressed in all four groups with no significant differences between any group (P = NS). There was no difference between the HI + isotype-matched antibody group and the HI + PBS group throughout the experiments (P = NS). ND did not affect MT1-MMP activation or expression CONCLUSIONS: Limb ischemia causes activation of MMP-2 and -9, which is eliminated by ND. ND animals undergoing hindlimb ischemia exhibit identical levels of active MMP-2 and -9 as animals that did not have hindlimb ischemia. Neutrophils may be an important activator of MMP-2 and the suppliers of MMP-9 in the ischemic hindlimb and may be essential for tissue remodeling, basement membrane degradation, and angiogenesis in ischemic limbs

Temporal expression and activation of matrix metalloproteinases-2, -9, and membrane type 1-matrix metalloproteinase following acute hindlimb ischemia.

OBJECTIVE: Matrix metalloproteinase (MMP) activity is essential for remodeling of ischemic tissue. The murine hindlimb ischemia model exhibits tissue remodeling including revascularization in part due to angiogenesis. MMP-2 and -9 are type IV collagenases necessary for basement membrane degradation as a part of extracellular matrix remodeling and angiogenesis. Polymorphonuclear leukocytes (PMNs) contain MMP-9, and in the presence of membrane type 1 (MT1)-MMP, are able to activate proMMP-2 in vitro. Activation of MMP-2 and -9 may be essential in ischemic limbs both for tissue remodeling and revascularization via angiogenesis. We hypothesized that MMP-2 and -9 would be activated following acute hindlimb ischemia (HI), and this activation would be temporally related to PMN infiltration. DESIGN OF STUDY: HI was achieved by unilateral femoral artery ligation in 20 FVB/N mice. Five mice underwent sham operation without hindlimb ischemia. Gastrocnemius muscle was harvested from both hindlimbs at 1, 3, 14, and 30 days following ligation and assayed for MMP-2, -9 (gelatin zymography), and MT1-MMP (Western blotting). MMP-2 and -9 expression and activation were analyzed by gelatin zymography and quantified by densitometry with NIH Image Analysis software. Neutrophils per high power field were counted. The results were expressed as a ratio of ischemic to nonischemic limbs and compared at each time point using ANOVA. RESULTS: Zymographic analysis revealed a 212% increase in active MMP-2 3 days postligation (P <.05). Active MMP-9 reached its maximum level (800% over baseline) on postoperative day 3 and continued to be elevated on day 14 (737% over baseline) (P <.05). The increase in active MMP-2 and -9 levels paralleled PMN infiltration that also peaked 3 days postligation (1184% over baseline) (P <.05). PMN count, MMP-2, and -9 all returned to baseline levels by postoperative Day 30. MT1-MMP was present in tissue samples from all time points as confirmed by Western blot. CONCLUSIONS: Limb ischemia causes an early activation of MMP-2 and -9 in temporal relation to PMN infiltration. HI may prime PMNs, leading to their sequestration in ischemic tissue. Primed PMNs, along with constitutively expressed MT1-MMP, may activate MMPs-2 and -9 and enable tissue remodeling essential for limb revascularization and angiogenesis.

Experimental hindlimb ischemia increases neutrophil-mediated matrix metalloproteinase activity: a potential mechanism for lung injury after limb ischemia.

BACKGROUND: Acute limb ischemia initiates a systemic inflammatory response, including pulmonary polymorphonuclear leukocyte (PMN) sequestration and acute lung injury. Lung injury is partly attributed to release by PMN's of extracellular matrix (ECM) modifying metalloproteinases (MMPs). We hypothesized that acute hindlimb ischemia (HI) would increase MMP activity in the lung and other organs and that systemic neutrophil depletion before HI would block this effect. STUDY DESIGN: Seventeen FVB/N Tie2/LacZ-182 SATO female mice were randomly divided into four groups: HI + PBS (Group 1), HI + antineutrophil antibody (Group 2), HI + isotype matched control antibody (Group 3), and no HI + PBS (Group 4). HI was achieved by unilateral femoral artery ligation. Neutrophil depletion was confirmed. Three days postligation, lung, liver, and kidney were harvested. MMP-2 and -9 expression and activation (gelatin zymography) and membrane type-1 MMP (MT1-MMP, western blotting) were quantified by densitometry and NIH Image Analysis software. Statistical significance was determined with an analysis of variance. RESULTS: Zymograms revealed a 46% increase in pulmonary proMMP-9 in Group 1 versus Group 4 (6,107 +/- 472 [mean +/- SEM] densitometry units [DU] versus 3,287 +/- 675 DU, p < 0.05). A similar trend was observed for active MMP-9 (3,189 +/- 541 DU versus 1,417 +/- 927 DU, P = 0.16). Neutrophil depletion (Group 2) decreased proMMP-9 levels by 51% (2,996 +/- 314 DU versus 6,107 +/- 472 DU, p < 0.05) and active MMP-9 by 75% (810 +/- 444 DU versus 3,189 +/- 541 DU, p < 0.05) compared with Group 1. Active MMP-2 increased 51% after HI (Group 1, 3,230 +/- 86 DU versus Group 4, 1,599 +/- 327 DU, p < 0.05). Neutrophil depletion decreased the HI-induced activation of MMP-2 by 43% (Group 2, 1,829 +/- 471 DU versus Group 1, 3,230 +/- 86 DU, p < 0.05). CONCLUSIONS: HI increases pulmonary proMMP-9, active MMP-9, and active MMP-2 levels. Neutrophil depletion blocks this effect. These data suggest that acute limb ischemia leads to PMN-mediated changes in MMP activity.

Polymorphonuclear neutrophils promote rFGF-2-induced angiogenesis in vivo.

BACKGROUND: The role of neutrophils in angiogenesis remains largely unknown. Recent evidence has shown that polymorphonuclear neutrophils (PMNs) produce several proangiogenic cytokines, including VEGF, TNF-alpha, IL-1, IL-6, and IL-8. In addition, PMN-derived proteinases promote endothelial cell migration. We hypothesized that PMNs may facilitate angiogenesis and that reducing circulating PMNs might alter the host angiogenic response. MATERIALS AND METHODS: We utilized a corneal pocket assay to compare rFGF-2-induced vessel formation in the corneas of mice with normal levels of circulating neutrophils to those in a neutropenic state. Circulating PMNs were reduced using serial intraperitoneal injections of monoclonal antibody to Gr-1. Slow release rFGF2 pellets were implanted into the corneas of neutropenic mice and controls. Corneal neovascularization, measured as vessel length and area of vessel in-growth, was quantified using slit-lamp microscopy on day 7. RESULTS: The average number of circulating PMNs was significantly reduced in the experimental group compared to the control group on days 1-7 (P < 0.05). No statistical differences in circulating monocytes or lymphocytes were observed from days 0 to 6. Mice in the experimental group had a vascular area of 2.58 +/- 0.2 mm(2) compared to 3.55 +/- 0.3 mm(2) in the control group (P < 0.05). CONCLUSIONS: Corneal neovascularization in response to rFGF-2 is diminished by PMN depletion. PMNs play an important role in facilitating rFGF-2-induced angiogenesis.