Effectiveness of triclosan-coated PDS Plus versus uncoated PDS II sutures for prevention of surgical site infection after abdominal wall closure: the randomised controlled PROUD trial.

BACKGROUND: Postoperative surgical site infections are one of the most frequent complications after open abdominal surgery, and triclosan-coated sutures were developed to reduce their occurrence. The aim of the PROUD trial was to obtain reliable data for the effectiveness of triclosan-coated PDS Plus sutures for abdominal wall closure, compared with non-coated PDS II sutures, in the prevention of surgical site infections. METHODS: This multicentre, randomised controlled group-sequential superiority trial was done in 24 German hospitals. Adult patients (aged ≥18 years) who underwent elective midline abdominal laparotomy for any reason were eligible for inclusion. Exclusion criteria were impaired mental state, language problems, and participation in another intervention trial that interfered with the intervention or outcome of this trial. A central web-based randomisation tool was used to randomly assign eligible participants by permuted block randomisation with a 1:1 allocation ratio and block size 4 before mass closure to either triclosan-coated sutures (PDS Plus) or uncoated sutures (PDS II) for abdominal fascia closure. The primary endpoint was the occurrence of superficial or deep surgical site infection according to the Centers for Disease Control and Prevention criteria within 30 days after the operation. Patients, surgeons, and the outcome assessors were masked to group assignment. Interim and final analyses were by modified intention to treat. This trial is registered with the German Clinical Trials Register, number DRKS00000390. FINDINGS: Between April 7, 2010, and Oct 19, 2012, 1224 patients were randomly assigned to intervention groups (607 to PDS Plus, and 617 to PDS II), of whom 1185 (587 PDS Plus and 598 PDS II) were analysed by intention to treat. The study groups were well balanced in terms of patient and procedure characteristics. The occurrence of surgical site infections did not differ between the PDS Plus group (87 [14·8%] of 587) and the PDS II group (96 [16·1%] of 598; OR 0·91, 95% CI 0·66-1·25; p=0·64). Serious adverse events also did not differ between the groups-146 of 583 (25·0%) patients treated with PDS Plus had at least one serious adverse event, compared with 138 of 602 (22·9%) patients treated with PDS II; p=0·39). INTERPRETATION: Triclosan-coated PDS Plus did not reduce the occurrence of surgical site infection after elective midline laparotomy. Innovative, multifactorial strategies need to be developed and assessed in future trials to reduce surgical site infections. FUNDING: Johnson & Johnson Medical Limited.

Peri-operative and complication management for adenocarcinoma of the oesophagus and oesophagigastric junction.

Surgical resection of oesophageal cancer still offers the only chance of cure for this disease. Nevertheless, oesophageal surgery may be accompanied by relevant mortality and morbidity, the causes of which can be both directly related to surgical technique as well as a large spectrum of non-surgical complications. In the last few years, improvements in patient selection and technical advances, as well as elaborated peri- and post-operative management, have helped to reduce these threats.The following article addresses important aspects of patient selection and evaluation, pre-operative preparation, anaesthesia, operative prophylaxis of complications, immediate post-operative care and complication management. All these factors are important contributions to improve the outcome in this challenging medical condition. Nowadays, experienced centres report operative mortality rates of around 5% for radical transthoracic resections (Low et al. 2007; Or-ringer et al. 2007; Ando et al. 2000; Karl et al. 2000; Whooley et al. 2003), down from rates of up to 30 or 40% in previous decades (Earlam and Cunha-Melo 1980). Many factors have contributed to these improvements; some authors claim large volume centres have a tendency to improve results, mostly due to more aggressive management of post-operative complications (Forshaw et al. 2006; van Lanschot et al. 2001; Smith et al. 2008). The following article summarizes the factors that have been identified in the past decades to influence the outcome of major surgery for the resection of adenocarcinoma of the oesophagus.

Portal vein arterialization increases hepatocellular apoptosis and inhibits liver regeneration.

BACKGROUND: Portal vein arterialization is performed in particular situations to guarantee sufficient blood flow in the portal vein. In addition, some authors have postulated a proliferation-promoting influence of portal vein arterialization on the liver tissue. However, portal vein arterialization is an unphysiological procedure: It increases portal blood flow and blood pressure as well as oxygenation of the liver tissue. On the other hand, it reduces the influx of hepatotrophic factors from the portal venous blood. The aim of these experiments was to investigate apoptosis and proliferation of hepatocytes during various conditions of the portal perfusion. MATERIALS AND METHODS: After 70% liver resection in Lewis rats, the following four experimental groups were formed differing in portal perfusion: (I) hyperperfused, nonarterialized; (II) flow-regulated, nonarterialized; (III) hyperperfused, arterialized; (IV) flow-regulated, arterialized. A warm ischemia of 30 min was kept in all groups. RESULTS: Portal vein arterialization of 70% reduced rat livers significantly reduced liver regeneration as shown by a significant reduction in liver weight, body weight, and liver function after 6 wk, in contrast to the group with 70% liver mass reduction and portal venous inflow of the portal vein. Furthermore, we found a significantly elevated number of apoptotic hepatocytes after portal vein arterialization. These results were independent from blood flow regulation of the arterialized portal vein, which caused no improvement of the results. CONCLUSIONS: Portal vein arterialization should be performed only temporarily and is clinically not recommended as a permanent option, because of the increased hepatocellular apoptosis and the very distinctive, negative long-term effects on liver weight.

Auxiliary liver transplantation with flow-regulated portal vein arterialization offers a successful therapeutic option in acute hepatic failure--investigations in heterotopic auxiliary rat liver transplantation.

Heterotopic auxiliary liver transplantation (HALT) with portal vein arterialization (PVA) was proposed in acute hepatic failure (AHF). However, clinical results of PVA are controversial because of lacking standardized flow-regulation. In rats, we examined HALT with flow-regulated PVA in AHF. Group A: HALT with flow-regulated PVA and 85% resection of the native liver to induce AHF [acute experiments (n = 8), killing after 7 days (n = 8) and after 6 weeks (n = 11)]. Group B: 85% liver-resection (n = 10). The average blood-flow in the arterialized portal vein in HALT achieved normal values (1.7 +/- 0.4 ml/min/g liver-weight). After reperfusion, the diameters of the sinusoids (6.4 +/- 0.6 microm), the postsinusoidal venules (31.1 +/- 3.3 microm) and the intersinusoidal distance (17.9+/-0.7 microm) also achieved normal values. The functional sinusoidal density amounted to 335 +/- 48/cm. The 6-week survival was nine of 11 with excellent liver function (Quick's value: 110% +/- 7.8%). The hepatobiliary radioisotope scanning with (99mTc) ethyl hepatic iminodiacetic acid (EHIDA) showed no significant differences between the native livers and grafts. The hepatocellular morphology was regular, apart from low-grade necroses in two grafts. The grafts' sinusoidal endothelial cells did not show any morphological changes. In group B, however, all rats died from AHF within 6 days. HALT with flow-regulated PVA achieved good results regarding microcirculation, morphology and function and can reliably bridge AHF.

Improved technique of heterotopic auxiliary rat liver transplantation with portal vein arterialization.

BACKGROUND AND AIMS: In acute, potentially reversible hepatic failure, auxiliary liver transplantation is a promising alternative approach. Using the auxiliary partial orthotopic liver transplantation (APOLT) method--the orthotopic implantation of auxiliary segments--most of the technical problems (lack of space for the additional liver mass, the portal vein reconstruction, and the venous outflow) are avoided, but extensive resections of the native liver and the graft are necessary. Erhard described the heterotopic auxiliary liver transplantation (HALT) with portal vein arterialization (PVA). Initial clinical results demonstrated that an adequate liver function can be achieved using this technique. We developed and improved a technique of HALT with flow-regulated PVA in the rat to perform further investigations. The aim of this paper is to explain in detail this improved experimental surgical technique. MATERIALS AND METHODS: Liver transplantations were performed in 122 male Lewis rats: After a right nephrectomy, the liver graft, which was reduced to about 30% of the original size, was implanted into the right upper quadrant of the recipient's abdomen. The infrahepatic caval vein was anastomosed end-to-side. The donor's portal vein was completely arterialized to the recipient's right renal artery in stent technique. Using a stent with an internal diameter of 0.3 mm, the flow in the arterialized portal vein was regulated to achieve physiologic parameters. The celiac trunk of the graft was anastomosed to the recipient's aorta, end-to-side. The bile duct was implanted into the duodenum. RESULTS: After improvements of the surgical technique, we achieved a perioperative survival of 90% and a 6-week survival of 80% in the last 112 transplantations. CONCLUSION: We developed a standardized and improved technique, which can be used for experiments of regeneration and inter-liver competition in auxiliary liver transplantation. Furthermore, this technique is suitable for the investigation of the influence of portal vein arterialization and portal hyperperfusion on liver microcirculation, function, and morphology.

Variability of size and shape of necrosis induced by radiofrequency ablation in human livers: a volumetric evaluation.

BACKGROUND: Definite size and shape of radiofrequency-induced ablations (RFAs) cannot be evaluated intraoperatively. Instead, surgeons choose a radiofrequency device that is supposed to cause a necrosis of a determined size greater than the malignant lesion. The aim of this study was to measure the variability of the induced necroses postoperatively and to define a reproducible ablation volume in human liver. METHODS: In 24 patients, 34 RFA procedures were performed with single applications of the device. The deployment was 3 cm (n=16), 4 cm (n=5), or 5 cm (n=13). The induced necroses were analyzed by volumetric reconstructions of computed tomography (CT) scans. Measured volumes were compared with the expected volumes. Furthermore, the shape of the necrosis was classified according to an index of the diameters. RESULTS: The measured volumes of postoperative necroses were 14 +/- 8 cm3 (deployment, 3 cm), 24 +/- 12 cm3 (4 cm), and 45 +/- 42 cm3 (5 cm). The diameter of a sphere fitted into the necroses reached 2.9 +/- .5 cm (3 cm), 3.5 +/- .7 cm (4 cm), and 4.1 +/- 1.1 cm (5 cm), at P<.02, significantly smaller than the deployment. The classification of shapes yielded a spherical shape (n=14), a teardrop shape (n=13), or an irregular shape (n=7). The energy consumption was 2.1 +/- 1.5 kJ/cm3 (3 cm), 2.6 +/- .5 kJ/cm3 (4 cm), or 3.5 +/- 2.0 kJ/cm3 (5 cm). CONCLUSIONS: The diameter of RFA-induced liver necrosis is significantly smaller than expected from needle deployment, especially with full-needle deployment. The shape of the lesion differs in more than half of the cases from the anticipated spherical pattern. The upper limit for reproducible necrosis induction is a tumor diameter of 3.4 cm.

Improved microcirculation of a liver graft by controlled portal vein arterialization.

BACKGROUND: The clinical results of portal vein arterialization (PVA) in liver transplantation are controversial without a standardized portal flow regulation. The aim of these experiments was to perform a flow-regulated PVA in liver transplantation, to examine the microcirculation and early graft function after heterotopic auxiliary liver transplantation (HALT) with flow-regulated PVA, and to compare this technique with HALT with porto-portal anastomosis. Using the recently developed orthogonal polarization spectral (OPS) imaging, for the first time the microcirculation of liver grafts with PVA was visualized. MATERIALS AND METHODS: HALT was performed in Lewis rats. The portal vein was either completely arterialized via the right renal artery in a standardized splint-technique (Group I, n = 8) or anastomosed end-to-end to the recipient's portal vein (Group II, n = 8). RESULTS: After reperfusion, the average blood flow in the portal vein was within the normal range in Group I (1.7 +/- 0.4 ml/min/g liver weight) and significantly higher than in Group II (1.2 +/- 0.2 ml/min/g liver weight). The functional sinusoidal density in Group I (335 +/- 48/microm) was significantly higher than in Group II (232 +/- 58/microm), whereas the diameter of the sinusoids and the postsinusoidal venules yielded no significant differences between both groups. The bile production was comparable (27 +/- 8 versus 29 +/- 11 microl/h/g liver weight). CONCLUSIONS: In our experiments it was possible to achieve an adequate flow regulation in the arterialized portal vein with good results concerning microcirculation and early graft function. We recommend that further investigations on liver transplantation with PVA should be performed with portal flow regulation, before PVA is employed in clinical transplantation.

Experimental evaluation of accuracy of radiofrequency ablation using conventional ultrasound or a third-dimension navigation tool.

BACKGROUND: Successful radiofrequency-induced ablation is dependent on correct placement of the device. The ultraguide system is a three-dimensional positioning system creating an overlay of the real-time ultrasound image and a virtual image of the device. METHODS: Tumor mimics were produced by injecting an agarose/cellulose/glycerol gel into pig livers on table. The precision of device placement was evaluated either using a freehand ultrasound procedure or using the aid of the ultraguide system either by an experienced or inexperienced surgeon. Tumor mimics were ablated by a protocol yielding an ablation only discretely larger than the mimics to enhance the importance of precise positioning. RESULTS: The sizes of the 40 tumor mimics were: largest diameter 14.1+/-2.2 mm, volume 0.89+/-0.40 cm(3). The largest diameter of ablation was 25.6+/-3.7 mm, the smallest diameter 21.9+/-2.9 mm, and the volume 7.20+/-2.38 cm(3). The experienced surgeon was successful in 7 of 10 cases with and without the ultraguide, the inexperienced surgeon in 4 of 10 without and 7 of 10 with the ultraguide. CONCLUSIONS: The ultraguide system may facilitate precise device placement for the less experienced surgeon. It seems worthwhile to evaluate a possible benefit of the system during placement of devices under operating room conditions.

Does continuous mucosal partial carbon dioxide pressure measurement predict leakage of intrathoracic esophagogastrostomy?

BACKGROUND: Gastroplasty after esophagectomy is associated with relevant morbidity due to anastomotic leakage of the esophagogastrostomy. The aim of this study was to find out whether continuous partial carbon dioxide pressure (pCO2) measurement of the gastric mucosa is an adequate method of monitoring the gastric tube during the postoperative course and of detecting patients with an anastomotic leakage. METHODS: Forty-seven patients with esophageal cancer underwent esophagectomy and gastric tube formation with intrathoracic esophagogastrostomy. Postoperatively, mucosal pCO2 of the gastric tube (pCO2i) was measured using continuous tonometry (TONOCAP, Datex Ohmeda). pCO2i was related to the arterial pCO2 (delta pCO2 = pCO2i - pCO2a). RESULTS: A total of 4,338 delta pCO2 measurements were recorded. On average, the pCO2i of each patient was monitored over a period of 92 hours. In 5 patients an anastomotic leakage of the esophagogastrostomy developed. The mean delta pCO2 of this group was 31.7 mm Hg (+/-19.3 SD) and significantly higher (p < 0.0001) than that of patients without anastomotic leakage (20.7 mm Hg +/- 12.8 SD). With a delta pCO2 cut-off point of 56 mm Hg measured for 5 hours, the sensitivity was 0.8, the specificity 0.9, and the positive predictive value 0.5. In patients with anastomotic leakage, the peak delta pCO2 preceded clinical symptoms. False positive delta pCO2 measurements (n = 4) were mainly due to severe pneumonia with long-term ventilation. CONCLUSIONS: Mucosal pCO2 measurement of the gastric tube can be used as an early indicator of a complicated postoperative course predicting anastomotic leakage of the esophagogastrostomy.