Expanded polytetrafluoroethylene (ePTFE)-covered stents versus bare stents for transjugular intrahepatic portosystemic shunt in people with liver cirrhosis.

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) is a widely used procedure for management of uncontrolled upper gastrointestinal bleeding and refractory ascites in people with liver cirrhosis. However, nearly half of the people experience shunt dysfunction and recurrent symptoms within one year of the procedure. Expanded polytetrafluoroethylene (ePTFE)-covered stents are assumed to decrease shunt dysfunction by approximately 20% to 30%. OBJECTIVES: To evaluate the benefits and harms associated with the use of expanded polytetrafluoroethylene (ePTFE)-covered stents versus bare stents in transjugular intrahepatic portosystemic shunts (TIPSs) for managing people with liver cirrhosis. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 28 February 2023. SELECTION CRITERIA: Randomised clinical trials comparing ePTFE-covered stents versus bare stents in TIPS for treatment of people with liver cirrhosis. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were 1. all-cause mortality, 2. procedure-related complications, and 3. health-related quality of life. Our secondary outcomes were 4. upper gastrointestinal bleeding, 5. recurrence of ascites, 6. hepatic encephalopathy, 7. kidney failure, 8. early thrombosis, 9. non-serious adverse events, and 10. shunt dysfunction. We used GRADE to assess certainty of evidence. We analysed outcome data at the maximum follow-up, except for the 'early thrombosis' outcome for which it was within 12 weeks after the TIPS procedure. MAIN RESULTS: We included four trials with 565 randomised participants (age range: 18 to 75 years; male range: 63.6% to 75.0%). A total of 527 participants provided data for analyses because of losses to follow-up. Two trials were conducted in China; one in France; and one in France, Spain, and Canada. Participants were classified with cirrhosis Child-Pugh class A, B, or C, and for some, the class was not reported. We used intention-to-treat principle (four trials) and per-protocol analysis (one trial) to meta-analyse the data. One trial compared ePTFE-covered stents versus bare stents of the same diameter and three trials compared ePTFE-covered stents versus stents of different diameters. ePTFE-covered stents versus bare stents of the same diameter One trial with 258 participants compared 8 mm covered stent versus 8 mm bare stent. Mortality in the covered stent group is possibly lower than in the bare stent group (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.43 to 0.92; low-certainty evidence). Upper gastrointestinal bleeding (RR 0.54, 95% CI 0.35 to 0.84), recurrence of ascites (RR 0.42, 95% CI 0.20 to 0.87), and shunt dysfunction (RR 0.42, 95% CI 0.28 to 0.61) occurred more often in the bare stent group than in the covered stent group (all low-certainty evidence). There was no difference in hepatic encephalopathy between groups (RR 1.10, 95% CI 0.76 to 1.61; very low-certainty evidence). The trial did not report data on procedure-related complications, health-related quality of life, early thrombosis, and segmental liver ischaemia (a non-serious adverse event). ePTFE-covered stents versus bare stents of different stent diameters Three trials compared ePTFE-covered stents versus bare stents of different diameters (10.5 (standard deviation (SD) 0.9) mm versus 11.7 (SD 0.8) mm; 8 mm versus 10 mm; and one trial used 10-mm stents that could be dilated from 8 mm to 10 mm). There was no evidence of a difference between the ePTFE-covered stents versus bare stents groups in mortality (RR 0.75, 95% CI 0.48 to 1.16; 3 trials, 269 participants), procedure-related complications (RR 0.53, 95% CI 0.05 to 5.57; 1 trial, 80 participants), upper gastrointestinal bleeding (RR 0.46, 95% CI 0.15 to 1.38; 3 trials, 269 participants), hepatic encephalopathy (RR 0.93, 95% CI 0.66 to 1.30; 3 trials, 269 participants), and kidney failure (RR 7.59, 95% CI 0.40 to 143.92; 1 trial, 121 participants) (all very low-certainty evidence). Recurrence of ascites (RR 0.30, 95% CI 0.11 to 0.85; 3 trials, 269 participants; low-certainty evidence), shunt dysfunction (RR 0.50, 95% CI 0.28 to 0.92; 3 trials, 269 participants; low-certainty evidence), and early thrombosis (RR 0.28, 95% CI 0.09 to 0.82; I2 = 0%; 3 trials, 261 participants; very low-certainty evidence) occurred more often in the bare stents group. There was no evidence of a difference in segmental liver ischaemia (RR 5.25, 95% CI 0.26 to 106.01; 1 trial, 80 participants; very low-certainty evidence). No trial presented data on health-related quality of life. Funding One trial did not clearly report funding sources. The remaining three trials declared that they had no funding with vested interests. AUTHORS' CONCLUSIONS: Based on the small number of trials with insufficient sample size and events, and study limitations, we assessed the overall certainty of evidence in the predefined outcomes as low or very low. Therefore, we are uncertain which of the two interventions (ePTFE-covered stents or bare stents of the same diameter and ePTFE-covered stents versus bare stents of different stent diameters) is effective for the evaluated outcomes. None of the four trials reported data on health-related quality of life, and data on complications were either missing or rarely reported. We lack high-quality trials to evaluate the role of ePTFE-covered stents for TIPS for managing people with liver cirrhosis.

Complications of e-PTFE Grafts in LDLT; Evaluation of Case Series.

BACKGROUND: The expanded polytetrafluoroethylene (ePTFE) grafts are used to drain anterior sector veins during the living donor liver transplantation procedure. We aimed to analyze the potentially life-threatening complications, such as the infection and migration of ePTFE grafts. METHODS: A total of 1264 liver transplantations (LTs) were performed for 1097 adult and 167 pediatric liver failure cases. In total, 1169 living and 95 cadaveric liver transplantation procedures were performed between 2011 and 2021. Right liver transplantation was performed in 1016 cases, including 1002 living donors and 14 cadaveric split right livers. Cadaveric LT was performed in 81 cases. RESULTS: For 1002 right living liver grafts, 905 vascular grafts were used during the backtable for anterior sector outflow venoplasty. The most commonly drained segments were 5 and 8 (472 cases); there were isolated (5 or 8) and multiple drained segments. Vascular graft migration was described in 7 of 905 (0.77%) patients. CONCLUSIONS: Although complication rates regarding ePTFE grafts are low, there are serious life-threatening causes of morbidity and mortality. We recommend cushioning the vascular graft with the omentum, which is effective in preventing graft migration.

Effect of Temperature on Thrombogenicity Testing of Biomaterials in an In Vitro Dynamic Flow Loop System.

To develop and standardize a reliable in vitro dynamic thrombogenicity test protocol, the key test parameters that could impact thrombus formation need to be investigated and understood. In this study, we evaluated the effect of temperature on the thrombogenic responses (thrombus surface coverage, thrombus weight, and platelet count reduction) of various materials using an in vitro blood flow loop test system. Whole blood from live sheep and cow donors was used to assess four materials with varying thrombogenic potentials: negative-control polytetrafluoroethylene (PTFE), positive-control latex, silicone, and high-density polyethylene (HDPE). Blood, heparinized to a donor-specific concentration, was recirculated through a polyvinyl chloride tubing loop containing the test material at room temperature (22-24°C) for 1 hour, or at 37°C for 1 or 2 hours. The flow loop system could effectively differentiate a thrombogenic material (latex) from the other materials for both test temperatures and blood species ( p < 0.05). However, compared with 37°C, testing at room temperature appeared to have slightly better sensitivity in differentiating silicone (intermediate thrombogenic potential) from the relatively thromboresistant materials (PTFE and HDPE, p < 0.05). These data suggest that testing at room temperature may be a viable option for dynamic thrombogenicity assessment of biomaterials and medical devices.

Comparison of animal and human blood for in vitro dynamic thrombogenicity testing of biomaterials.

BACKGROUND: To determine suitable alternatives to human blood for in vitro dynamic thrombogenicity testing of biomaterials, four different animal blood sources (ovine, bovine, and porcine blood from live donors, and abattoir porcine blood) were compared to fresh human blood. METHODS: To account for blood coagulability differences between individual donors and species, each blood pool was heparinized to a donor-specific concentration immediately before testing in a dynamic flow loop system. The target heparin level was established using a static thrombosis pre-test. For dynamic testing, whole blood was recirculated at room temperature for 1 h at 200 ml/min through a flow loop containing a single test material. Four materials with varying thrombotic potentials were investigated: latex (positive control), polytetrafluoroethylene (PTFE) (negative control), silicone (intermediate thrombotic potential), and high-density polyethylene (HDPE) (historically thromboresistant). Thrombus weight and surface area coverage on the test materials were quantified, along with platelet count reduction in the blood. RESULTS: While donor-specific heparin levels varied substantially from 0.6 U/ml to 7.0 U/ml among the different blood sources, each source was able to differentiate between the thrombogenic latex and the thromboresistant PTFE and HDPE materials (p < 0.05). However, only donor ovine and bovine blood were sensitive enough to differentiate an increased response for the intermediate thrombotic silicone material compared to PTFE and HDPE. CONCLUSIONS: These results demonstrated that multiple animal blood sources (particularly donor ovine and bovine blood) may be suitable alternatives to fresh human blood for dynamic thrombogenicity testing when appropriate control materials and donor-specific anticoagulation levels are used.

Constrictive pericarditis caused by pericardial substitution using expanded polytetrafluoroethylene.

BACKGROUND: Expanded polytetrafluoroethylene (ePTFE) is commonly used as a pericardial substitute during cardiac surgery to prevent cardiac injury during re-sternotomy. However, although rare, constrictive pericarditis associated with ePTFE has been reported. MATERIAL, METHODS AND RESULTS: Here, we report a rare case of constrictive pericarditis developed due to severe restriction of cardiac motion associated with the ePTFE membrane used as a pericardial substitute. Hemodynamic improvement has been achieved by surgical removal of the ePTFE membrane and exudates within the overlapped portion of the ePTFE membranes, and dissection of the epicardial fibrous thickening. CONCLUSION: Considering the risk of constrictive pericarditis, we believe that the use of ePTFE membranes as a pericardial substitute should be carefully indicated for only selected patients.

Occupational Lung Disease Caused by Exposure to Polytetrafluoroethylene.

We herein report a 45-year-old-man with multiple foreign body granulomas in the lungs caused by polytetrafluoroethylene (PTFE). A mass in the right lower lobe of the lung and bilateral centrilobular lung nodules were found unexpectedly during the patient's visit to a hospital for a respiratory infection. The patient's occupation for 26 years involved spraying PTFE. A lung biopsy using bronchoscopy revealed granulomatous lesions and giant cells. The presence of fluorine in the granulomatous lesions was confirmed using an electron probe microanalyzer with wavelength dispersive spectrometer. Fluorine is a component of PTFE and is not found in normal lung tissue.

Thrombogenicity of biomaterials depends on hemodynamic shear rate.

BACKGROUND: While it is well recognized that different biomaterials induce thrombosis at low shear rates, the effect of high shear rates may be quite different. We hypothesize that the amount of thrombus formation on a given material can be greatly influenced by the local shear rate. METHODS: We tested this hypothesis with two different whole blood perfusion loop assays to quantify biomaterial thrombogenicity as a function of shear stress. One assay uses obstructive posts (pins) of material positioned centrally in a tube perfused at high shear rate of >5000/s for 24 h. A second assay uses a parallel plate chamber to perfuse low (<150/s), medium (~500/s), and high shear rates over 96 h. We evaluated the thrombogenicity of seven different biomaterials including stainless steel, acrylic, ceramic, Dacron, polytetrafluoroethylene (PTFE), silicone, and polyvinyl chloride (PVC). RESULTS: For the pin assay, thrombus mass was significantly greater for stainless steel than either zirconia ceramic or acrylic (p < 0.001). Similarly, the parallel plate chamber at high shear showed that steel and PTFE (p < 0.02) occluded the chamber faster than acrylic. In contrast, a low shear parallel plate chamber revealed that stainless steel and PTFE were least thrombogenic, while silicone, Dacron, and other plastics such as acrylic were most thrombogenic. Histology revealed that high shear thrombi had a large proportion of platelets not seen in the low shear fibrin-rich thrombi. CONCLUSION: This differential thrombogenicity based on shear rate conditions may be important in the selection of biomaterials for blood-contacting devices.

Teflon Granuloma: A Common Cause of Recurrent Trigeminal Neuralgia.

BACKGROUND: Trigeminal neuralgia (TN) is a common pain syndrome of the nervous system,. Although about 90% patients who were refractory to medications could be free from pain after microvascular decompression (MVD), some patients did experience recurrence. The study aimed to analyze clinical characteristics of patients with recurrent TN, recurrence factors of TN, and prognosis after re-do MVD. METHODS: Clinical data and at least 12 months follow-up of patients with recurrent TN who underwent re-do MVD in our hospital from 2005 to 2020 were collected and analyzed. RESULTS: A total of 14 patients with recurrent TN were enrolled eventually; adhesive arachnoid membranes were found in all patients. Teflon granuloma was found in 10 patients, new neurovascular compression (NVC) in 3 patients, and vascular displacement in 1 patient. Pain disappeared in 12 patients and relieved in 2 patients, but 4 patients experienced mild facial numbness and 1 patient suffered from incision infection after re-do MVC. No serious surgery-related complications and pain recurrences were recorded. CONCLUSIONS: Teflon granuloma was the most common cause of TN recurrence in current study, new NVC was also saw in some patients. Patients with recurrent TN could get satisfactory results from re-do MVD.

Premature Deaths Due to Silicosis in Turkey, 2006-2017: A Twelve-Year Longitudinal Study.

BACKGROUND: Deaths due to epidemics of silicosis still continue to be reported both in developing and developed countries, and silica exposure from different sectors remains an important occupational health concern. AIMS: To identify characteristics of silicosis cases by focusing on a developing country and evaluate the frequency of and factors related to premature deaths and also reveal preventable causes of premature deaths in silicosis. STUDY DESIGN: Retrospective cohort. METHODS: We reviewed the records of 9769 patients who were diagnosed with occupational diseases in Istanbul Occupational Diseases Hospital between 2006 and 2017. According to International Classification of Diseases (ICD)-10 codes, 1473 silicosis cases were detected. The sociodemographic characteristics, job characteristics, comorbidities, serological, functional, and radiological data, and follow-up time were obtained from the medical records. Mortality data were gathered from The National Death Notification System of Ministry of Health. RESULTS: The study examined 9769 cases diagnosed with an occupational disease, and 15.0% (n = 1473) of them were diagnosed with silicosis. The median age of silicosis patients was 40.0 years, and 26.9% of them were child labor when they started to work in dusty industries. Child labor was mostly seen among dental technicians (57.7%), denim sandblasters (46.4%), and miners (37.0%). In the follow-up period, 26.3% of Teflon sandblasters, 11.1% of coal miners, 8.6% of denim sandblasters had died before their average life expectancy, and the years of loss of life was 26.0 ± 11.6 years all over the group. Premature death was associated with occupation [hazard ratio (Teflon sandblasting): 3.93, CI: 1.43-10.78; hazard ratio (marble production): 4.4, CI: 1.02-19.21]; large opacities in posterior anterior chest X-ray [hazard ratio: 2.14, CI: 1.18-3.86]; tuberculosis [hazard ratio: 2.60, CI: 1.42- 4.76]; and reduction in forced vital capacity (forced vital capacity% ≤80) during diagnosis [hazard ratio: 4.43, CI: 2.22-8.83]. CONCLUSION: More than a quarter of silicosis cases are those who start working in dusty industries at an early age. Factors associated with premature death in patients with silicosis are patient occupation, large opacities on chest X-ray, tuberculosis, and pulmonary function loss at diagnosis.

Two cases of asymptomatic Teflon granulomas following microvascular decompression mimicking cerebellopontine angle tumours: lessons learnt in the neuro-oncology multidisciplinary team.

We present the cases of two patients with asymptomatic Teflon granulomas which were incidentally found years after microvascular decompression and presented to the neuro-oncology multidisciplinary team as possible cerebellopontine angle tumours. Teflon granulomas can be asymptomatic and they can radiologically resemble cerebellopontine angle tumours. It is important that all relevant information is available to the neuro-oncology multidisciplinary team for adequate assessment and appropriate treatment recommendations.

Patches of different types for carotid patch angioplasty.

BACKGROUND: Extracranial carotid artery stenosis is the major cause of stroke, which can lead to disability and mortality. Carotid endarterectomy (CEA) with carotid patch angioplasty is the most popular technique for reducing the risk of stroke. Patch material may be made from an autologous vein, bovine pericardium, or synthetic material including polytetrafluoroethylene (PTFE), Dacron, polyurethane, and polyester. This is an update of a review that was first published in 1996 and was last updated in 2010. OBJECTIVES: To assess the safety and efficacy of different types of patch materials used in carotid patch angioplasty. The primary hypothesis was that a synthetic material was associated with lower risk of patch rupture versus venous patches, but that venous patches were associated with lower risk of perioperative stroke and early or late infection, or both. SEARCH METHODS: We searched the Cochrane Stroke Group trials register (last searched 25 May 2020); the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 4), in the Cochrane Library; MEDLINE (1966 to 25 May 2020); Embase (1980 to 25 May 2020); the Index to Scientific and Technical Proceedings (1980 to 2019); the Web of Science Core Collection; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) portal. We handsearched relevant journals and conference proceedings, checked reference lists, and contacted experts in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials (RCTs) comparing one type of carotid patch with another for CEA. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed eligibility, risk of bias, and trial quality; extracted data; and determined the quality of evidence using the GRADE approach. Outcomes, for example, perioperative ipsilateral stroke and long-term ipsilateral stroke (at least one year), were collected and analysed. MAIN RESULTS: We included 14 trials involving a total of 2278 CEAs with patch closure operations: seven trials compared vein closure with PTFE closure, five compared Dacron grafts with other synthetic materials, and two compared bovine pericardium with other synthetic materials. In most trials, a patient could be randomised twice and could have each carotid artery randomised to different treatment groups. Synthetic patch compared with vein patch angioplasty Vein patch may have little to no difference in effect on perioperative ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (odds ratio (OR) 2.05, 95% confidence interval (CI) 0.66 to 6.38; 5 studies, 797 participants; very low-quality evidence). Vein patch may have little to no difference in effect on long-term ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (OR 1.45, 95% CI 0.69 to 3.07; P = 0.33; 4 studies, 776 participants; very low-quality evidence). Vein patch may increase pseudoaneurysm formation when compared with synthetic patch, but the evidence is very uncertain (OR 0.09, 95% CI 0.02 to 0.49; 4 studies, 776 participants; very low-quality evidence). However, the numbers involved were small. Dacron patch compared with other synthetic patch angioplasty Dacron versus PTFE patch materials  PTFE patch may reduce the risk of perioperative ipsilateral stroke (OR 3.35, 95% CI 0.19 to 59.06; 2 studies, 400 participants; very low-quality evidence). PTFE patch may reduce the risk of long-term ipsilateral stroke (OR 1.52, 95% CI 0.25 to 9.27; 1 study, 200 participants; very low-quality evidence). Dacron may result in an increase in perioperative combined stroke and transient ischaemic attack (TIA) (OR 4.41 95% CI 1.20 to 16.14; 1 study, 200 participants; low-quality evidence) when compared with PTFE. Early arterial re-stenosis or occlusion (within 30 days) was also higher for Dacron patches. During follow-up for longer than one year, more 'any strokes' (OR 10.58, 95% CI 1.34 to 83.43; 2 studies, 304 participants; low-quality evidence) and stroke/death (OR 6.06, 95% CI 1.31 to 28.07; 1 study, 200 participants; low-quality evidence) were reported with Dacron patch closure, although numbers of outcome events were small. Dacron patch may increase the risk of re-stenosis when compared with other synthetic materials (especially with PTFE), but the evidence is very uncertain (OR 3.73, 95% CI 0.71 to 19.65; 3 studies, 490 participants; low-quality evidence). Bovine pericardium patch compared with other synthetic patch angioplasty Bovine pericardium versus PTFE patch materials  Evidence suggests that bovine pericardium patch results in a reduction in long-term ipsilateral stroke (OR 4.17, 95% CI 0.46 to 38.02; 1 study, 195 participants; low-quality evidence). Bovine pericardial patch may reduce the risk of perioperative fatal stroke, death, and infection compared to synthetic material (OR 5.16, 95% CI 0.24 to 108.83; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 4.39, 95% CI 0.48 to 39.95; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 7.30, 95% CI 0.37 to 143.16; 1 study, 195 participants; low-quality evidence, respectively), but the numbers of outcomes were small. The evidence is very uncertain about effects of the patch on infection outcomes. AUTHORS' CONCLUSIONS: The number of outcome events is too small to allow conclusions, and more trial data are required to establish whether any differences do exist. Nevertheless, there is little to no difference in effect on perioperative and long-term ipsilateral stroke between vein and any synthetic patch material. Some evidence indicates that other synthetic patches (e.g. PTFE) may be superior to Dacron grafts in terms of perioperative stroke and TIA rates, and both early and late arterial re-stenosis and occlusion. Pseudoaneurysm formation may be more common after use of a vein patch than after use of a synthetic patch. Bovine pericardial patch, which is an acellular xenograft material, may reduce the risk of perioperative fatal stroke, death, and infection compared to other synthetic patches. Further large RCTs are required before definitive conclusions can be reached.

External compression due to seroma of ventricular assist device outflow graft.

A 45-year-old woman with repaired complex congenital heart disease, who underwent placement of Jarvik 2000, a ventricular assist device (VAD) for 4 years, experienced abdominal pain due to outflow graft compression caused by seroma formation between the outflow graft and ringed Gore-Tex graft. We exchanged the pump of Jarvik 2000 and punched several small holes in the new ringed Gore-Tex graft. Seroma formation between the two grafts should be considered as a cause of outflow graft obstruction in patients with the long-term support of VAD, and additional surgical interventions to the ringed Gore-Tex graft may prevent this complication.

The Potential Relation Between polytetrafluoroethylene Grafts after Open Reconstructions for Abdominal Aortic Aneurysm and Perigraft Seromas.

BACKGROUND: The presence of sac enlargement after abdominal aortic aneurysm (AAA) open repair, a condition usually called perigraft seroma (PGS), nearly always has a benign behavior. Some theories implicated for PGS formation include coagulation abnormalities, fibroblast inhibition, low-grade infection, or improper graft handling. METHODS: This is a retrospective study including patients treated for AAA in 2 academic vascular surgery departments from 2007 to 2014, where 1 center preferably used polytetrafluoroethylene (PTFE) grafts whereas the preference of other center was mostly Dacron graft. The definition of PGS was conceived as a fluid collection around the graft on CT scan imaging with a radiodensity ≤25 Hounsfield units, reaching at least 30 mm in diameter and beyond the third postoperative month. Analysis was performed between patients with and without PGS. RESULTS: Seventy-eight patients met the inclusion criteria: 42 received Dacron and 36 PTFE grafts. Twenty-three (29.5%) patients accomplished the PGS diagnosis. Having a PTFE graft was the strongest factor for PGS formation on multivariate analysis. The medium seroma size was 42 mm (range, 30-90.6 mm) and the mean time from AAA repair to PGS detection was 26 months (range, 4-106 months). Three patients of the 23 with PGS required surgical repair, all of them were successfully treated: 2 by endovascular means and the remaining with explantation and Dacron reconstruction. CONCLUSIONS: PGS formation is not an unusual complication after open reconstructions for AAA treatment. This is especially true for PTFE grafts, and thus, closer follow-up is warranted if using this material. Treatment is clearly needed when symptoms appear; however, preventive strategies with either endovascular relining or reopen reconstructions require an individual approach counterbalancing benefits versus risk of the procedures.

Complex Fistula Formations After Orbital Fracture Repair With Teflon: A Review of 3 Case Reports.

ABSTRACT: The authors present 3 unique cases of complex fistula formations because of orbital fracture repair with a Teflon (polytetrafluroethylene) implant. A 26-year-old man presented with dacryocystitis and a cutaneous fistula 8 years after left orbital floor and medial wall fracture repair with a Teflon implant. A 46-year-old woman suffered orbital trauma after a motor vehicle accident as a teenager and the fracture was repaired with Teflon implant. Thirty-two years later, she presented with lower eyelid fistula, ectropion, and retraction. A 65-year-old woman also previously had Teflon implants for the repair of her left inferior and lateral orbital rim after a motor vehicle accident. Twenty-five years later, she presented with chronic infections involving the repaired areas, as well as left lower lid ectropion and fistula formation. The woven material nature of Teflon acted as a nidus for infection, inflammation, and led to complex cutaneous fistula formations in these patients.

Complications of Alloplast Rhinoplasty and Their Management: A Comprehensive Review.

In Asian countries, augmentation rhinoplasty is especially common, where alloplastic implants are used much more commonly than autologous tissues. In rhinoplasty, such artificial materials include silicone, expanded polytetrafluoroethylene (ePTFE), porous high-density polyethylene (pHDPE), and acellular human dermis. As the use of implants has become increasingly common in rhinoplasty, more adverse effects such as infection, extrusion, movement, irregularities, absorption, prolonged swelling, seroma, and contracture have been recognized and reported in the literature. Surgeons should be able to recognize these probable complications and manage them successfully. Early detection and prompt management of the complication are essential for minimizing the severity of the deformity. Proper management of complications is key for the success of dorsal augmentation using alloplastic implants.

Fluorine detection in the lung tissue of a worker with interstitial pulmonary fibrosis and long-term occupational exposure to polytetrafluoroethylene and perfluorooctanoic acid.

Exposure to polytetrafluoroethylene (PTFE), a compound used in nonstick cookware coating and a variety of other applications, is known to cause acute lung injury and granulomatous pneumonitis. It is uncertain whether PTFE and compounds used in its manufacture, such as perfluorooctanoic acid (PFOA), cause chronic lung disease. Here we report a case of interstitial pulmonary fibrosis in a 71-year-old man who died following a brief illness clinically suspected to be acute respiratory distress syndrome. He had a 25-year history of occupational exposure to PTFE and PFOA. At postmortem examination, the lungs demonstrated diffuse alveolar damage (DAD) superimposed on interstitial pulmonary fibrosis. The interstitial fibrosis lacked fibroblast foci and exhibited basilar and subpleural accentuation with focal microscopic honeycombing. Within the fibrotic lung parenchyma were scattered giant cells containing birefringent translucent particles. Scanning electron microscopy and energy-dispersive x-ray spectroscopy (SEM-EDS) were performed. A majority of the birefringent particles demonstrated a prominent peak for fluorine by EDS analysis. This is the first report to document the presence of fluorine, an elemental constituent of PTFE and PFOA, in fibrotic lung tissue. Careful evaluation of other individuals with long-term exposure to PTFE and/or PFOA appears warranted to better elucidate the spectrum of pulmonary disease associated with these compounds.

Massive Ossification with Hematopoietic Marrow on Both Surfaces of the Expanded Polytetrafluoroethylene Artificial Dura Mater.

BACKGROUND: Artificial dural substitute made from an expanded polytetrafluoroethylene (ePTFE) sheet has been widely used in surgical application. CASE DESCRIPTION: We describe a 19-year-old woman in whom massive ossification with hematopoietic marrow was noted on both surfaces of an ePTFE sheet during epilepsy surgery. At age 8, she underwent decompressive craniectomy for a ruptured arteriovenous malformation in the right frontal lobe, followed by duraplasty with an ePTFE sheet and autologous cranioplasty fixed with titanium miniplates. CONCLUSIONS: Since the ossification was prominent in the wrinkle dents of the ePTFE sheet and fibrotic membrane with repetitive hemorrhagic events was noted under the ePTFE sheet, the most plausible mechanism of ossification development is the organization of epiartificial and subartificial dural hematoma. Surgeons should be aware of the possibility of ossification development when working with ePTFE sheets for duraplasty.

Cardiocutaneous fistula 15 years postcardiac surgery: A real challenge.

Late Cardiocutaneous Fistula (CF) is an uncommon but potentially serious postoperative complication of cardiac surgery. We present the successful treatment of a 58-year-old female who developed a CF extending from the left ventricular apex into the left breast related to mitral valve replacement 15 years ago.

Long-term results of polytetrafluoroethylene versus saphenous vein repair of degenerative carotid artery aneurysm.

OBJECTIVE: To compare the results of polytetrafluoroethylene (PTFE) and great saphenous vein (GSV) bypass after resection of a degenerative aneurysm of the carotid artery. METHODS: From January 1994 to November 2017, 37 patients (27 men) with a mean age of 58 years (range, 39-82 years) with a degenerative aneurysm of the carotid artery (median diameter, 28 mm; range, 19-42 mm), underwent resection of the aneurysm followed by a bypass with either a GSV (n = 10) or a PTFE prosthesis (n = 27). Although 31 patients were asymptomatic, 6 patients were symptomatic: transient ischemic attack (n = 4), minor stroke (n = 1), and compression of the hypoglossal nerve (n = 1). The preoperative workup included duplex ultrasound examination of the arteries to the head, and angiography or computed tomography angiography. All patients were operated under general anesthesia and six were intubated through the nose. Sixteen patients were monitored through transcutaneous oximetry. No shunt was used in this series. In 10 patients receiving a PTFE graft, the external carotid artery was implanted in the prosthesis. Mean follow-up was 16.9 ± 2 years (95% confidence interval, 14.5-19.3 years). Primary end points were the 30-day combined stroke/death rate, graft infection, late graft patency, and late stroke-free survival. Secondary end points were cranial nerve injury and length of postoperative hospital stay. RESULTS: Postoperative mortality was nil in both groups. One postoperative stroke was observed in the PTFE group, whereas none occurred in the GSV group (P = .84). No graft infection was observed in either group. At 10 years, survival in the GSV group was 80 ± 12%, and survival in the PTFE group was 76 ± 8% (log-rank [Mantel-Cox], P = .85). In the GSV group, graft patency at 7 and 10 years was 85 ± 13%. In the PTFE group B, graft patency was 100% (log-rank [Mantel-Cox], P = .12). No late stroke was observed. Two transient cranial nerve injuries were observed in the GSV group (20%) and two in the PTFE group (8%) (P = .97). Length of hospital stay was comparable in both groups (GSV group, 6 days; PTFE group, 5 days; P = .12). CONCLUSIONS: This study suggests that, after resection of a degenerative aneurysm of the carotid artery, bypass with a PTFE prosthesis gives comparable results to those obtained with the GSV. We recommend sparing the GSV and instead using a PTFE prosthesis in patients with a degenerative aneurysm of the carotid artery.

Polytetrafluoroethylene granuloma-associated facial palsy following microvascular decompression.

OBJECTIVE: Microvascular decompression (MVD) may be employed in the management of hemifacial spasm (HFS), wherein a pledget of polytetrafluoroethylene (i.e., Teflon, Chemours, Wilmington DE) is sometimes introduced to separate an offending vessel from the cisternal segment of facial nerve. Rarely, Teflon may cause a granulomatous reaction resulting in nerve palsy. We here present the first case series of facial palsy thought to be secondary to Teflon granuloma following MVD for HFS. METHODS: A data repository of 1,312 patients with facial palsy was reviewed to identify individuals who had previously undergone MVD for HFS. Data collected include age at time of MVD, age at onset of facial weakness and at presentation, House-Brackmann scores, clinician-graded facial function using the Electronic Facial Paralysis Assessment scale, imaging findings, and therapeutic interventions and outcomes. RESULTS: Six patients meeting criteria were identified. Average time between MVD with Teflon placement and onset of facial weakness was 16.1 (±4.9) years (range 9.3-23.3 years). Initial House-Brackmann scores were as follows: four patients with V/VI and one each with III/VI and IV/VI. Interventions included eyelid weight placement (n = 3), chemodenervation (n = 2), static suspension with tensor fascia latae (n = 2), dynamic reanimation with cranial nerves V to VII transfer (n = 1), and temporalis muscle transfer (n = 1). CONCLUSION: Teflon granuloma should be considered in the differential diagnosis for patients presenting with new onset facial weakness with a previous history of MVD for HFS. It remains unknown whether early granuloma extirpation is effective. Prompt diagnosis allows consideration of time-sensitive nerve transfer procedures to reanimate facial function. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1422-1427, 2020.