Biological Sealants Research Articles

Leakage of Intestinal Anastomoses: A New Solution to the Old Problem

Leakage of intestinal anastomoses remains an issue in view of the increasing number of patients who need reconstructive interventions in different parts of the gastrointestinal tract. Researchers around the world are actively looking for methods of strengthening intestinal anastomoses. The literature presents various approaches to sealing intestinal anastomoses in experimental animals using allografts, biological sealants, polymer film materials, etc. This article classifies and analyzes innovative methods of strengthening intestinal anastomoses to prevent their leakage. We also describe a concept of developing polymer membranes for interventions on hollow organs and our experience in this field of work and making of medical devices at the premises of a university research laboratory.

Dual-crosslinking immunostimulatory hydrogel synchronously suppresses pancreatic fistula and pancreatic cancer relapse post-resection

In pancreatic cancer (PC), surgical resection remains the sole curative option, albeit patients undergoing resection are susceptible to postoperative pancreatic fistula (PF) formation and tumor recurrence. An unmet need exists for a unified strategy capable of concomitantly averting PF and tumor relapse to mitigate morbidity in PC patients after surgery. Herein, an original dual crosslinked biological sealant hydrogel (methacrylate-hyaluronic acid-dopamine (MA-HA-DA) and sulfhydryl-hyaluronic acid-dopamine (SH-HA-DA)) was engineered as a drug depot and loaded with polydopamine-cloaked cytokine interleukin-15 and platelets conjugated with anti-TIGIT. In vitro analyses validated favorable tissue adhesion, cytocompatibility, and stability of the hydrogels. In a PF rodent model, the hydrogel effectively adhered to the pancreatic stump, sealing the severed pancreatic end and impeding post-operative elevations in amylase and lipase. In PC murine models, hydrogels potently stimulated CD8+ T and NK cells to deter residual tumor re-growth and distant metastasis. This innovative hydrogel strategy establishes a new framework for concomitant prevention of PF and PC recurrence.

Bronchoscopic Management of COPD and Advances in Therapy.

Chronic Obstructive Pulmonary Disease (COPD) is a highly prevalent and morbid disease marked by irreversible structural changes in the lungs. Bronchoscopic therapies have significantly expanded the treatment armamentarium for patients with persistent symptoms by reducing the physiologic detriments of hyperinflation in a less invasive fashion than surgical lung volume reduction. The spectrum of bronchoscopic techniques to reduce hyperinflation includes endobronchial valves, coils, thermal ablation, and biologic sealants. Other therapies focus on reducing parasympathetic tone and mucus hypersecretion and include targeted lung denervation, bronchial rheoplasty, and cryospray techniques. In this article, we will review the variety of techniques for bronchoscopic lung volume reduction, both established and investigational, along with their respective benefits and complications and will briefly review other investigational therapies for COPD.

65 A Retrospective Cohort Study of the Use of Vivostat PRF Autologous Platelet-Rich Fibrin in Patient Outcomes in Total Knee Replacement Surgery

Abstract Aim Vivostat PRF is an autologous platelet-rich fibrin spray that is prepared in theatre from the patient’s own blood and has shown that its use as a biological sealant intra-operatively reduces transfusion rates and decreases haemarthrosis after total knee replacement (TKR). We undertook a retrospective time-based comparative cohort study examining relevant patient outcomes, comparing patients undergoing TKR surgery with Vivostat PRF versus without. Method 106 patients undergoing TKR surgery between 2008 and 2017 were studied. Patients were selected for inclusion via hospital records and divided into two groups: those who had received Vivostat PRF intra-operatively (n = 59), and those who hadn’t (n = 47) (the control group). Primary outcomes included haemoglobin drop pre- vs post-operatively, range of movement (ROM) at follow-up appointments, number of days post-operatively in hospital until the patient was able to manage stairs, post-operative pain scores and transfusion rates. Results There was a statistically significant difference in the haemoglobin drop between the two groups, with a drop of 27.5g/L in the study group compared to 31.9g/L in the control group (p = 0.019). ROM at day 3 post-operatively was better in the Vivostat group by 5.0o (p = 0.0018), and at 3 months post-operatively there was 7.8o greater movement (p = 0.004). No statistically significant differences were seen in the pain scores; however, early rehabilitation performance was improved in the Vivostat group, with a quicker time to being able to manage stairs post-operatively (p = 0.04). There was no statistically significant difference in transfusion rates. Conclusions This study showed that there are benefits in using Vivostat PRF in TKR surgery.

Application of biomaterials for complex anal fistulae

Complex anal fistulae remain a challenge for the medical sector as conventional treatments put patients at risk of incontinence. Clinicians and researchers have become interested in the application of bioresorbable materials, as a means of avoiding invasive procedures and/or secondary procedures. Advances in polymer chemistry and processing techniques, the range of biomaterial medical devices has expanded since first implemented in the early 1990s. Devices were initially modeled off the collagen Surgisis® anal fistula plug and biologic sealants, primarily as tissue scaffolds. Clinical evaluation of these biomaterial medical devices initially generated great enthusiasm, however; subsequent studies observed low—moderate success rates. The next generation of biomaterial devices focus on novel device design and the incorporation of bioactives and biologics for the amelioration of disease persistent factors. This review focuses on the biomaterials utilized, the form of medical device developed and the recent inclusion of dual-purpose scaffolds for complex anal fistulae treatments.

Decision-making and practice habits from international expert surgeons regarding operative techniques and mitigation strategies to reduce pancreatic fistula following pancreatoduodenectomy

Presenter: Fabio Casciani MD | University of Pennsylvania Background: Employment of pancreatic fistula mitigation strategies during pancreatoduodenectomy (PD) offers numerous decision-making points. Particularly, despite ample retrospective studies and RCTs, no consensus exists concerning optimal anastomotic techniques and use of adjuncts for risk mitigation. Methods: A questionnaire was sent to a select panel of international pancreatic surgery experts, recognized for their clinical and scientific authority. Their thought-processes and practice regarding pancreatico-enteric anastomotic technique and fistula mitigation strategy employment were explored through checkbox questions, free-text responses, and situational clinical vignettes. Results: 60 surgeons from 22 countries, encompassing 73,304 career pancreatic resections (median pancreatectomy/PD volume: 1200/705, median career duration: 22 years), contributed. When asked to report their usual fistula mitigation strategy employment, 55% always use PJ, whereas PG is never adopted by 58%. (Table) Concerning PJ technique, 80% use duct-to-mucosa reconstruction frequently/always (≥75% of the time) - more often by Cattel-Warren technique rather than Blumgart (45 vs. 33%). Trans-anastomotic stents are always placed by few experts (17%), with the internal type preferred. Roux-en-Y limb reconstruction, biological sealants and tissue patches are exceedingly rarely applied. Similarly, prophylactic somatostatin-analogues are infrequently employed (never: 57%; selectively: 38%). Lastly, 45% of authorities selectively employ transperitoneal drainage rather than routinely, but not one absolutely omits drains. However, there is no conformity regarding drain number, type or system. When considering such approaches collectively, the most prevalent “bundle” chosen (47%) is the combination of PJ, no stent, external drainage and omission of Somatostatin-analogue, with two-thirds declaring to be flexible -rather than rigid- in their fistula risk mitigation approaches. In the case of perceived increased fistula risk, the most frequent adjuncts chosen are placement of additional drains (27%), the use of prophylactic Somatostatin (20%), and externalized stents (18%). (Table, bottom) Conversely, total pancreatectomy is opted by just 10%, while a PG (rather than PJ) by only 5%. This was confirmed throughout clinical vignettes depicting stepwise increasing risk scenarios: the use of dunking/invaginating PJ, stents, drains and Somatostatin-analogues increased accordingly (+146%, +94%, +39% and +380%, respectively). Conversely, the employment of PG reconstruction and Roux limb orientation remained uncommon (≈6%). Finally, facing a challenging scenario where the pancreatic tissue is easily disrupted when placing stitches in a soft, thick parenchyma with an eccentric < 1mm duct, most specialists would perform a new anastomosis after cutting back the pancreas (42%), whereas others directly perform a dunking/invagination PJ (27%). Again, constructing a PG (12%) or converting to a total pancreatectomy (10%) are both rarely considered. Other, additive mitigation strategies employed in such a challenging situation are: stents (58%), additional drain placement and Somatostatin-analogue administration (37% each), autologous tissue patches (23%) and jejunal/gastrostomy tubes to optimize nutrition (20%). Conclusion: A tension between a rigid versus a flexible approach to fistula risk mitigation during PD is tangible among experts. Most vary their practice according to perceived, advanced risk, with dunking/invaginating PJ (rather than PG), stents, drains and Somatostatin-analogues each being modestly advocated in such circumstances. These insights indicate that approaches to pancreatico-enteric reconstruction are variable, and optimal, absolute solutions for high-risk anastomoses are still unresolved.

Collagen-Based Tissue Engineering Strategies for Vascular Medicine.

Cardiovascular diseases (CVDs) account for the 31% of total death per year, making them the first cause of death in the world. Atherosclerosis is at the root of the most life-threatening CVDs. Vascular bypass/replacement surgery is the primary therapy for patients with atherosclerosis. The use of polymeric grafts for this application is still burdened by high-rate failure, mostly caused by thrombosis and neointima hyperplasia at the implantation site. As a solution for these problems, the fast re-establishment of a functional endothelial cell (EC) layer has been proposed, representing a strategy of crucial importance to reduce these adverse outcomes. Implant modifications using molecules and growth factors with the aim of speeding up the re-endothelialization process has been proposed over the last years. Collagen, by virtue of several favorable properties, has been widely studied for its application in vascular graft enrichment, mainly as a coating for vascular graft luminal surface and as a drug delivery system for the release of pro-endothelialization factors. Collagen coatings provide receptor–ligand binding sites for ECs on the graft surface and, at the same time, act as biological sealants, effectively reducing graft porosity. The development of collagen-based drug delivery systems, in which small-molecule and protein-based drugs are immobilized within a collagen scaffold in order to control their release for biomedical applications, has been widely explored. These systems help in protecting the biological activity of the loaded molecules while slowing their diffusion from collagen scaffolds, providing optimal effects on the targeted vascular cells. Moreover, collagen-based vascular tissue engineering substitutes, despite not showing yet optimal mechanical properties for their use in the therapy, have shown a high potential as physiologically relevant models for the study of cardiovascular therapeutic drugs and diseases. In this review, the current state of the art about the use of collagen-based strategies, mainly as a coating material for the functionalization of vascular graft luminal surface, as a drug delivery system for the release of pro-endothelialization factors, and as physiologically relevant in vitro vascular models, and the future trend in this field of research will be presented and discussed.

The Beneficial Effects of Minimizing Blood Loss in Pancreatoduodenectomy.

The aim of this study was to elucidate the impact of intraoperative blood loss on outcomes following pancreatoduodenectomy (PD). The negative impact of intraoperative blood loss on outcomes in PD has long been suspected but not well characterized, particularly those factors that may be within surgeons' control. From 2001 to 2015, 5323 PDs were performed by 62 surgeons from 17 institutions. Estimated blood loss (EBL) was discretized (0 to 300, 301 to 750, 751 to 1300, and >1300 mL) using optimal scaling methodology. Multivariable regression, adjusted for patient, surgeon, and institutional variables, was used to identify associations between EBL and perioperative outcomes. Factors associated with both increased and decreased EBL were elucidated. The relative impact of surgeon-modifiable contributors was estimated through beta coefficient standardization. The median EBL of the series was 400 mL [interquartile range (IQR) 250 to 600]. Intra-, post-, and perioperative transfusion rates were 15.8%, 24.8%, and 37.2%, respectively. Progressive EBL zones correlated with intra- but not postoperative transfusion in a dose-dependent fashion (P < 0.001), with a key threshold of 750 mL EBL (8.14% vs 40.9%; P < 0.001). Increasing blood loss significantly correlated with poor perioperative outcomes. Factors associated with increased EBL were trans-anastomotic stent placement, neoadjuvant chemotherapy, pancreaticogastrostomy reconstruction, multiorgan or vascular resection, and elevated operative time, of which 38.7% of the relative impact was "potentially modifiable" by the surgeon. Conversely, female sex, small duct, soft gland, minimally invasive approach, pylorus-preservation, biological sealant use, and institutional volume (≥67/year) were associated with decreased EBL, of which 13.6% was potentially under the surgeon's influence. Minimizing blood loss contributes to fewer intraoperative transfusions and better perioperative outcomes for PD. Improvements might be achieved by targeting modifiable factors that influence EBL.

Risk Factors and Mitigation Strategies for Pancreatic Fistula After Distal Pancreatectomy: Analysis of 2026 Resections From the International, Multi-institutional Distal Pancreatectomy Study Group.

To identify a clinical fistula risk score following distal pancreatectomy. Clinically relevant pancreatic fistula (CR-POPF) following distal pancreatectomy (DP) is a dominant contributor to procedural morbidity, yet risk factors attributable to CR-POPF and effective practices to reduce its occurrence remain elusive. This multinational, retrospective study of 2026 DPs involved 52 surgeons at 10 institutions (2001-2016). CR-POPFs were defined by 2016 International Study Group criteria, and risk models generated using stepwise logistic regression analysis were evaluated by c-statistic. Mitigation strategies were assessed by regression modeling while controlling for identified risk factors and treating institution. CR-POPF occurred following 306 (15.1%) DPs. Risk factors independently associated with CR-POPF included: age (<60 yrs: OR 1.42, 95% CI 1.05-1.82), obesity (OR 1.54, 95% CI 1.19-2.12), hypoalbuminenia (OR 1.63, 95% CI 1.06-2.51), the absence of epidural anesthesia (OR 1.59, 95% CI 1.17-2.16), neuroendocrine or nonmalignant pathology (OR 1.56, 95% CI 1.18-2.06), concomitant splenectomy (OR 1.99, 95% CI 1.25-3.17), and vascular resection (OR 2.29, 95% CI 1.25-3.17). After adjusting for inherent risk between cases by multivariable regression, the following were not independently associated with CR-POPF: method of transection, suture ligation of the pancreatic duct, staple size, the use of staple line reinforcement, tissue patches, biologic sealants, or prophylactic octreotide. Intraoperative drainage was associated with a greater fistula rate (OR 2.09, 95% CI 1.51-3.78) but reduced fistula severity (P < 0.001). From this large analysis of pancreatic fistula following DP, CR-POPF occurrence cannot be reliably predicted. Opportunities for developing a risk score model are limited for performing risk-adjusted analyses of mitigation strategies and surgeon performance.

The beneficial effects of minimizing blood loss in pancreatoduodenectomy

Background: The negative impact of intraoperative blood loss on outcomes in pancreatoduodenectomy (PD) has long been suspected but not well characterized, particularly factors that may be within the surgeon's control. Methods: From 2001 to 15, 5323 PDs were performed by 62 surgeons from 17 institutions. Estimated blood loss (EBL) was discretized (0–300, 301–750, 751–1300, and >1300 mL) using optimal scaling methodology. Multivariable regression, adjusted for patient, surgeon, and institution variables, was used to identify associations with EBL zones and perioperative outcomes. Contributors to minimizing EBL were elucidated. Beta coefficient standardization determined the relative impact of surgeon-modifiable contributors. Results: The median EBL of the series was 400 mL (IQR 250–600). Intra-, post-, and perioperative transfusion rates were 15.8, 24.8, and 30.9% respectively. Progressive EBL zones correlated with intra – but not postoperative transfusion in a dose-dependent fashion (R 2 = 0.9128), with a key threshold of 750 mL EBL (8.14% vs 40.9%; p < 0.001). Increasing blood loss significantly correlated with poor perioperative outcomes (Table 1). Factors associated with “increased” EBL were: trans-anastomotic stent use, neoadjuvant chemotherapy, PG reconstruction, multiorgan or vascular resection, and elevated operative time, of which 45.5% of the relative impact was potentially modifiable by the surgeon. Conversely, female gender, small duct, soft gland, minimally invasive approach, pylorus-preservation, biological sealant use, and institutional volume (>67/year) were associated with “decreased” EBL, of which 17.5% was potentially under the surgeon's influence. Conclusion: Minimizing blood loss contributes to fewer intraoperative transfusions and better perioperative outcomes for PD. Improvements might be achieved by targeting modifiable factors that influence EBL.Table 1The Influence of Blood Loss on Perioperative Outcomes Following PDVariablePatientsIntraoperative transfusionAny complication: accordion ≥1Severe complication: accordion ≥3CR-POPFLength of stay >13 days30-day readmission90-day mortalityEBL (mL)(N, %)(OR, 95% CI)(OR, 95% CI)(OR, 95% CI)(OR, 95% CI)(OR, 95% CI)(OR, 95% CI)(OR, 95% CI)0–3002359 (44.3)l (Ref.)1 (Ref.)1 (Ref.)1 (Ref.)l(Ref.)l(Ref.)l(Ref.)301–7502104 (39.5)1.648 (0.897–3.026)1.318* (1.160–1.498)1.132 (0.960–1.334)1.489* (1.222–1.815)1.282* (1.103–1.489)0.945 (0.724–1.234)1.041 (0.648–1.671)751–130053.8 (10-1)6.811* (3.362–13.80)2.015* (1.626–2.496)1.370* (1.062–1.767)1.261 (0.904–1.760)1 667* (1.318–2.108)1.539* (1.063–2.230)1.283 (0.691–2.384)>1300322 (6.1)27.244* (12.525–59.20)2.394* (1.515–3.156)1.876* (1.391–2.528)1.507* (1.017–2.233)2.726* (2.077–3.578)2.247* (1.499–3.369)2.445* (1.269–4.710)*: p < 0.05 Open table in a new tab *: p < 0.05

Risk Factors and Mitigation Strategies for Pancreatic Fistula after Distal Pancreatectomy: Analysis of 2,026 Resections from the International, Multi-Institution Distal Pancreatectomy Study Group

Clinically relevant pancreatic fistula (CR-POPF) after distal pancreatectomy (DP) is a dominant contributor to procedural morbidity, yet risk factors attributable to CR-POPF and effective practices to reduce its occurrence remain elusive. This multinational, retrospective study of 2,026 DPs involved 52 surgeons at 10 institutions (2001 to 2016). CR-POPFs were defined by International Study Group criteria, and risk models generated using stepwise logistic regression analysis were evaluated by c-statistic. Mitigation strategies were assessed by regression modeling while controlling for identified risk factors and treating institution. CR-POPF occurred in 306 (15.1%) DPs. Risk factors independently associated with fistula included: BMI 25–30 kg/m2: odds ratio (OR) 1.38, 95% CI 1.01–1.87; ≥30 kg/m2: OR 1.52, 95% CI 1.11–2.09, hypoalbuminenia (OR 1.56, 95% CI 1.03–2.44), high-risk pathology (neuroendocrine or benign: OR 1.62, 95% CI 1.23–2.14), concomitant splenectomy (OR 2.02, 95% CI 1.27–3.21), and vascular resection (OR 2.25, 95% CI 1.23–4.11). However, the model had poor predictive discrimination (c-statistic 0.635). Intraoperative drainage was more frequently utilized in cases of increased fistula risk (OR 2.11, p = 0.013). CR-POPF rates varied by method of transection (stapled: 12.7% vs handsewn: 19.1% vs energy device: 24.2%, p < 0.001); however, in a multivariable model, method of transection, suture ligation of the pancreatic duct, staple size, and the use of mesh reinforcement, tissue patches, biologic sealants, or prophylactic octreotide were not independently associated with CR-POPF. From this multi-institutional analysis of pancreatic fistula after DP, CR-POPF cannot be reliably predicted, prohibiting risk score development and effective risk-adjusted analysis of mitigation strategies or surgeon performance.

The effect of biological sealants and adhesive treatments on matrix metalloproteinase expression during renal injury healing.

BackgroundRenal injuries are relatively common in cases of abdominal trauma. Adhesives and sealants can be used to repair and preserve damaged organs. Using a rat model, this study explores the activity of different matrix metalloproteinases (MMP) during the healing of renal injuries treated by two biological adhesives (TachoSil and GelitaSpon) and a new synthetic elastic cyanoacrylate (Adhflex).MethodsRenal traumatic injuries were experimentally induced in 90 male Wistar rats by a Stiefel Biopsy Punch in the anterior aspect of the left kidney. Animals were divided into five groups: 1, sham non-injured (n = 3); 2, non-treated standard punch injury (n = 6); 3, punch injury treated with TachoSil (n = 27); 4, punch injury treated with GelitaSpon (n = 27); and, 5, punch injury treated with Adhflex (n = 27). Wound healing was evaluated 2, 6, and 18 days after injury by determining the expression of MMPs, and the histopathological evolution of lesions.FindingsHistologically, the wound size at 6 days post-injury was larger in Adhflex-treated samples than in the other treatments, but the scarring tissue was similar at 18 days post-injury. Only the MMPs subtypes 1, 2, 8, 9, and 13 were sufficiently expressed to be quantifiable. Both time since injury and treatment type had a significant influence on MMPs expression. Two days after injury, the expression of MMP8 and MMP9 was predominant. MMP2 expression was greater 6 days after injury. The Adhflex-treated group had a significantly higher MMPs expression than the other treatment groups at all healing stages.ConclusionsAll three sealant treatments induced almost similar expression of MMPs than untreated animals indicating a physiological healing process. Given that all renal trauma injuries must be considered emergencies, both biological and synthetic adhesives, such as Adhflex, should be considered as a treatment options.

The Physiological Incubation Biosimulator (PIBS): An Improved Ex Vivo Experimental Setup for the Mechanical Stability of Biological Sealants in Surgical Procedures.

Tissue-bound fibrin sealants are used in a wide array of surgical procedures. The microenvironmental interaction between sealant and application site is often poorly evaluated due to a lack of suitable experimental models. A physiological incubation biosimulator (PIBS) was developed to test biological sealants in an ex vivo setup under physiological conditions comparable to the microenvironment at application site (temperature, humidity, pressure). PIBS was validated by a study on the effectiveness of TachoSil for leak closure at pancreatic resection sites. Defined defects in a thoracic membrane of porcine origin were sealed by TachoSil. Integrity of the sealing was tested in the presence of active pancreatic fluid over 60 minutes. Heat-inactivated pancreatic fluid and electrolyte solution served as controls. The time to leakage was recorded and experimental groups were analyzed by Kaplan-Meier analysis. PIBS produced reliable results. TachoSil lead to a leakage rate of 96% after incubation with active pancreatic fluid (p = 34), which was significantly higher compared with heat-inactivated pancreatic fluid (p = 34, 52%) or electrolyte solution (p = 20, 19%). PIBS is an effective tool to evaluate microenvironmental effects on the adhesive strength of biomaterials. Tissue sealing effect of TachoSil is diminished in a "pancreatic" microenvironment rich with pancreatic enzymes. Our results might therefore explain the reason of the findings of randomized controlled trials recently published on this subject.

The potential effect of biological sealants on colorectal anastomosis healing in experimental research involving severe diabetes.

Colorectal anastomoses continuous to pose a significant challenge in current surgical practice. Anastomotic leakage remains one of the most frequent and dramatic complications of colorectal surgery, even in centres of high specialisation. Diabetes is a well-established independent factor which results in higher anastomotic leakage rates. Fibrin sealants have been applied in experimental and clinical studies for the prevention of anastomotic dehiscence. However, little is known regarding their impact on diabetic patients. Several fibrin sealants have been proposed as adjunct to standard surgical techniques to prevent leakage from colonic anastomoses following the reversal of temporary colostomies, approved for general haemostasis. This review summarises current advances in colorectal anastomoses and provides evidence that may strengthen the need for tissue sealants in colorectal anastomoses of diabetic patients. We searched Medline (1966-2016) and Scopus (2004-2016) for current evidence in the field. To date, there is no evidence to support the use of fibrin sealants as an adjunct in diabetic patients who undergo colorectal surgery. Experimental animal models with extreme diabetes could be of significant use in the present field and further research is needed prior to application of fibrin sealants in a clinical setting.

Long-term Imaging of the Lungs After Sealant Bronchoscopic Lung Volume Reduction

The aim of the study was to assess the pulmonary temporal changes after bronchoscopic lung volume reduction (BLVR) using sealants for treatment of emphysema. We retrospectively assessed all chest computerized tomography (CT) and F-18 fluorodeoxyglucose (FDG) positron emission tomography CT scans of patients treated at our institution with BLVR. Eleven patients were treated with sealants: 4 with biological sealants and 7 with synthetic sealants. The first CT scan after biological sealant treatment showed no abnormalities in 8 lobes and 5 nodules, and 3 consolidations in 7 lobes. All findings resolved within 3 months, except for a nodule that decreased after 2 months and remained stable for 9 years. The first CT scan after utilizing the synthetic sealant showed abnormalities in each treated lobe: 19 nodules/masses (16 cavitary, 3 solid) and 3 consolidations. Follow-up CT scans were available for 16 nodules/masses: 1 resolved, 12 slowly decreased in size, 1 remained unchanged, and 2 grew. Of 3 consolidations 1 resolved and 2 decreased in size. FDG positron emission tomography CT scans performed in 2 patients showed FDG uptake higher than mediastinal background activity in 2 nodules in the same patient. Pulmonary changes after BLVR are variable. After treatment with biological sealants, most findings resolve within 3 months. In contrast, after synthetic sealants, although the majority regress over time, some show waxing and waning in growth that can mimic malignancy. FDG uptake in some of these lesions is suggestive of chronic inflammation. Radiologists should be aware of the spectrum of these pulmonary changes to avoid misdiagnosis of lung cancer.

The influence of fellowship training on the practice of pancreatoduodenectomy

BackgroundThere has been a proliferation of gastrointestinal surgical fellowships; however, little is known regarding their association with surgical volume and management approaches. MethodsSurveys were distributed to members of GI surgical societies. Responses were evaluated to define relationships between fellowship training and surgical practice with pancreatoduodenectomy (PD). ResultsSurveys were completed by 889 surgeons, 84.1% of whom had completed fellowship training. Fellowship completion was associated with a primarily HPB or surgical oncology-focused practice (p < 0.001), and greater median annual PD volume (p = 0.030). Transplant and HPB fellowship-trained respondents were more likely to have high-volume (≥20) annual practice (p = 0.005 and 0.029, respectively). Regarding putative fistula mitigation strategies, HPB-trained surgeons were more likely to use stents, biologic sealants, and autologous tissue patches (p = 0.007, <0.001 and 0.001, respectively). Surgical oncology trainees reported greater autologous patch use (p = 0.003). HPB fellowship-trained surgeons were less likely to routinely use intraperitoneal drainage (p = 0.036) but more likely to utilize early (POD ≤ 3) drain amylase values to guide removal (p < 0.001). Finally, HPB fellowship-trained surgeons were more likely to use the Fistula Risk Score in their practice (29 vs. 21%, p = 0.008). ConclusionFellowship training correlated with significant differences in surgeon experience, operative approach, and use of available fistula mitigation strategies for PD.

Technical strategy for dealing with bleeding during thoracoscopic lung surgery.

Uncontrollable bleeding caused by vascular injury is an important reason for conversion to thoracotomy during thoracoscopic lung surgery. Demmy et al. (1) summarized several effective methods for dealing with bleeding, such as the use of thrombostatic material, biological sealant, or discreet utilization of energy sources. However, managing more severe bleeding is quite challenging even for experienced thoracoscopic surgeons. The most common solution for this situation is compression or tamponade of the injured site while converting to open thoracotomy (1,2). We have previously described a series of skills named the “suction-compressing angiorrhaphy technique (SCAT)” for dealing with severe bleeding due to vascular injury during thoracoscopic lung surgery (3). Bleeding control and angiorrhaphy were both achieved through thoracoscopy in most of the cases of vascular injury in our center. Here, we present our technical strategy for dealing with bleeding and vascular injury during thoracoscopic lung surgery with a video series.

Bronchoscopic treatment of end-stage chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a progressive, debilitating disease that in its final stages cripples the patient. The disappointing results of the National Emphysema Treatment Trial study led to a decrease in the acceptance of lung volume reduction surgery as a therapy. Thus, it became clear that debilitated COPD patients would need innovative alternative nonsurgical procedures to potentially alleviate their symptoms. This review will address the various techniques of bronchoscopic lung volume reduction (BLVR). In recent years, a variety of noninvasive BLVR procedures were developed in the hope of improving the respiratory status of these patients. BLVR aims to decrease the extent of hyperinflation due to emphysema and result in a beneficial effect similar to that from surgical resection. The most widely used BLVR devices are: endobronchial valves, foam sealant, metallic coils, airway bypass stents and vapor thermal ablation.In the USA, BLVR remains in the experimental phase. The treatment modalities should be individually tailored for each patient. Endobronchial valves are designed to exclude the most affected emphysematous regions from ventilation in order to induce lobar absorption atelectasis. Airway bypass stents target homogenous emphysema, whereas valves and thermal vapor ablation target heterogeneous emphysema. Biological sealants and endoscopic coil implants have been used in both homogenous and heterogeneous emphysema. BLVR appears to be safer than surgery and presents an attractive alternative for the treatment of COPD patients. Unfortunately, the outcome data to date are inconclusive; the procedures remain experimental and any benefits unproven. However, the data that are emerging continue to appear promising.

Reconstructing the Infected Aortic Root with Antibiotic Impregnated Biological Glue

Prosthetic valve dehiscence and persistent infection are two complications following reconstruction of the aortic root in destructive endocarditis. A technique is described involving the principles of aggressive debridement, closure of large abscess cavities with biological material incorporating a slurry of antibiotic-impregnated biological sealant, and replacement of the aortic valve with an aortic allograft valve. This strategy appears to have been successful in preventing persistent endocarditis and valve dehiscence in a limited number of patients.

Evaluation of the Effectiveness of Injection Termination and Hydraulic Controls for Leakage Containment

One of the greatest concerns that the public has with large-scale adoption of CCS technology is the potential risk of carbon dioxide leakage from sequestration reservoirs. Among other things, addressing these concerns will require developing intervention and remediation strategies that can be quickly and effectively implemented should leakage occur. The three main methods proposed for remediation of leakage from carbon storage reservoirs are: (1) termination of CO2 injection activities, (2) injection of a chemical or biological sealant to act as a flow barrier [1] or (3) the development of hydraulic barriers [2–4]. Creating hydraulic barriers relies on the injection of water in the overlying aquifer with or without injection or production of fluid from the injection reservoir in order to manipulate the pressure field to stop or reverse leakage. Here we first investigate the effectiveness of passive remediation (stopping CO2 injection), and then determine its effectiveness in combination with a variety of different hydraulic controls such as injection of water above the fault, injection of water below the fault and production of brine in the lower reservoir. Regardless of when the leak is detected, simulation results show that passive remediation (stopping injection) almost immediately reduces the leakage rate by an order of magnitude. Depending on the degree of residual trapping, leakage can be even further reduced. For example, with a maximum residual CO2 saturation of greater than 20%, leakage rates drop by another factor of 4 or more. In many cases stopping injection may reduce the leakage to the extent that is so small that it reaches an acceptable level. However in the case where further reductions are desired, for example, in order to completely stop leakage, the implementation of hydraulic controls may be necessary. The most effective method for completely stopping leakage is to inject water into the overlying aquifer near the breach in the caprock. Drawbacks of using this method alone is that while it stops leakage during water injection, leakage resumes after the cessation of water injection. In order to prevent leakage from continuing after water injection ends, the CO2 plume in the injection reservoir must be displaced away from the bottom of the fault zone. Displacing the CO2 plume away from the fault is accomplished by injection of water below the fault while injecting water above the fault, and by producing reservoir brine on the opposite side of the CO2 plume. Reservoir brine production helps pull mobile CO2 away from the bottom of the fault. In this study, production rates are established by balancing water injection rates, therefore reducing costs and surface storage issues associated with leakage remediation. The most effective hydraulic controls for stopping CO2 leakage combine brine extraction from the storage reservoir with water injection into the overlying aquifer and storage reservoir near the fault. Overall this study demonstrates that temporally limited, multi-stage remediation strategies using a combination of stopping injection and hydraulic controls can permanently terminate leakage while having the additional benefit of dissolving most of the CO2 in the overlying aquifer into the resident brine. This finding should provide assurances to industry, policy makers, and the public that intervention measures can quickly and effectively mitigate the risks of leakage should leakage occur.