Cooling Effects Occur in Hepatic Microwave Ablation At Low Vascular Flow Rates and in Close Proximity to Liver Vessels - Ex Vivo.

Background. The impact of vascular cooling effects in hepatic microwave ablation (MWA) is controversially discussed. The objective of this study was a systematic assessment of vascular cooling effects in hepatic MWA ex vivo. Methods. Microwave ablations were performed in fresh porcine liver ex vivo with a temperature-controlled MWA generator (902-928 MHz) and a non-cooled 14-G-antenna. Energy input was set to 9.0 kJ. Hepatic vessels were simulated by glass tubes. Three different vessel diameters (3.0, 5.0, 8.0 mm) and vessel to antenna distances (5, 10, 20 mm) were examined. Vessels were perfused with saline solution at nine different flow rates (0-500 mL/min). Vascular cooling effects were assessed at the largest cross-sectional ablation area. A quantitative and semi-quantitative/morphologic analysis was carried out. Results. 228 ablations were performed. Vascular cooling effects were observed at close (5 mm) and medium (10 mm) antenna to vessel distances (P < .05). Vascular cooling effects occurred around vessels with flow rates ≥1.0 mL/min (P < .05) and a vessel diameter ≥3 mm (P < .05). Higher flow rates did not result in more distinct cooling effects (P > .05). No cooling effects were measured at large (20 mm) antenna to vessel distances (P > .05). Conclusion. Vascular cooling effects occur in hepatic MWA and should be considered in treatment planning. The vascular cooling effect was mainly affected by antenna to vessel distance. Vessel diameter and vascular flow rate played a minor role in vascular cooling effects.

Risk factors for upper and lower type prolonged postoperative ileus following surgery for Crohn's disease.

PURPOSE: Prolonged postoperative ileus (PPOI) is common after bowel resections, especially in Crohn's disease (CD). The pathophysiology of PPOI is not fully understood. PPOI could affect only the upper or lower gastrointestinal (GI) tract. The aim of this study was to assess risk factors for diverse types of PPOI, particularly to differentiate PPOI of upper and lower GI tract. METHODS: A retrospective analysis of 163 patients with CD undergoing ileocecal resection from 2015 to 2020 in a single center was performed. PPOI of the upper GI tract was predefined as the presence of vomiting or use of nasogastric tube longer than the third postoperative day. Lower PPOI was predefined as the absence of defecation for more than three days. Independent risk factors were identified by multivariable logistic regression analysis. RESULTS: Overall incidence of PPOI was 42.7%. PPOI of the upper GI tract was observed in 30.7% and lower PPOI in 20.9% of patients. Independent risk factors for upper PPOI included older age, surgery by a resident surgeon, hand-sewn anastomosis, prolonged opioid analgesia, and reoperation, while for lower PPOI included BMI ≤ 25 kg/m2, preoperative anemia, and absence of ileostomy. CONCLUSION: This study identified different risk factors for upper and lower PPOI after ileocecal resection in patients with CD. A differentiated upper/lower type approach should be considered in future research and clinical practice. High-risk patients for each type of PPOI should be closely monitored, and modifiable risk factors, such as preoperative anemia and opioids, should be avoided if possible.

Periportal fields cause stronger cooling effects than veins in hepatic microwave ablation: an in vivo porcine study.

BACKGROUND: Vascular cooling effects are a well-known source for tumor recurrence in thermal in situ ablation techniques for hepatic malignancies. Microwave ablation (MWA) is an ablation technique to be considered in the treatment of malignant liver tumors. The impact of vascular cooling in MWA is still controversial. PURPOSE: To evaluate the influence of different intrahepatic vessel types, vessel sizes, and vessel-to-antenna-distances on MWA geometry in vivo. MATERIAL AND METHODS: Five MWAs (902-928 MHz) were performed with an energy input of 24.0 kJ in three porcine livers in vivo. MWA lesions were cut into 2-mm slices. The minimum and maximum radius of the ablation area was measured for each slice. Distances were measured from ablation center toward all adjacent hepatic vessels with a diameter of ≥1 mm and within a perimeter of 20 mm around the antenna. The respective vascular cooling effect relative to the maximum ablation radius was calculated. RESULTS: In total, 707 vessels (489 veins, 218 portal fields) were detected; 370 (76%) hepatic veins and 185 (85%) portal fields caused a cooling effect. Portal fields resulted in higher cooling effects (37%) than hepatic veins (26%, P < 0.01). No cooling effect could be observed in close proximity of vessels within the central ablation zone. CONCLUSION: Hepatic vessels influenced MWA zones and caused a distinct cooling effect. Portal fields resulted in more pronounced cooling effect than hepatic veins. No cooling effect was observed around vessels situated within the central white zone.

CT-based quantification of short-term tissue shrinkage following hepatic microwave ablation in an in vivo porcine liver model.

BACKGROUND: Microwave ablation (MWA) is a minimally invasive treatment option for solid tumors and belongs to the local ablative therapeutic techniques, based on thermal tissue coagulation. So far there are mainly ex vivo studies that describe tissue shrinkage during MWA. PURPOSE: To characterize short-term volume changes of the ablated zone following hepatic MWA in an in vivo porcine liver model using contrast-enhanced computer tomography (CECT). MATERIAL AND METHODS: We performed multiple hepatic MWA with constant energy parameters in healthy, narcotized and laparotomized domestic pigs. The volumes of the ablated areas were calculated from venous phase CT scans, immediately after the ablation and in short-term courses of up to 2 h after MWA. RESULTS: In total, 19 thermally ablated areas in 10 porcine livers could be analyzed (n = 6 with two volume measurements during the measurement period and n = 13 with three measurements). Both groups showed a statistically significant but heterogeneous volume reduction of up to 12% (median 6%) of the ablated zones in CECT scans during the measurement period (P < 0.001 [n = 13] and P = 0.042 [n = 6]). However, the dimension and dynamics of volume changes were heterogenous both absolutely and relatively. CONCLUSION: We observed a significant short-term volume reduction of ablated liver tissue in vivo. This volume shrinkage must be considered in clinical practice for technically successful tumor treatment by MWA and therefore it should be further investigated in in vivo studies.

Healing of rectal advancement flaps for anal fistulas in patients with and without Crohn's disease: a retrospective cohort analysis.

BACKGROUND: Surgical closure of anal fistulas with rectal advancement flaps is an established standard method, but it has a high degree of healing failure in some cases. The aim of this study was to identify risk factors for anal fistula healing failure after advancement flap placement between patients with cryptoglandular fistulas and patients with Crohn's disease (CD). METHODS: From January 2010 to October 2020, 155 rectal advancement flaps (CD patients = 55, non-CD patients = 100) were performed. Patients were entered into a prospective database, and healing rates were retrospectively analysed. RESULTS: The median follow-up period was 189 days (95% CI: 109-269). The overall complication rate was 5.8%. The total healing rate for all rectal advancement flaps was 56%. CD patients were younger (33 vs. 43 years, p < 0.001), more often female (76% vs. 30%, p < 0.001), were administered more immunosuppressant medication (65% vs. 5%, p < 0.001), and had more rectovaginal fistulas (29% vs. 8%, p = 0.001) and more protective stomas (49% vs. 2%, p < 0.001) than patients without CD. However, no difference in healing rate was noted between patients with or without CD (47% vs. 60%, p = 0.088). CONCLUSIONS: Patients with anal fistulas with and without Crohn's disease exhibit the same healing rate. Although patients with CD display different patient-specific characteristics, no independent factors for the occurrence of anal fistula healing failure could be determined. Trial registration Not applicable due to the retrospective study design.

Immediate post-interventional contrast-enhanced computed tomography overestimates hepatic microwave ablation - an in vivo animal study.

Objectives: Contrast-enhanced computed tomography (CECT) is used to monitor technical success immediately after hepatic microwave ablation (MWA). However, it remains unclear, if CECT shows the exact extend of the thermal destruction zone, or if tissue changes such as peri-lesionary edema are depicted as well. The objective of this study was to correlate immediate post-interventional CECT with histological and macroscopic findings in hepatic MWA in porcine liver in vivo.Methods: Eleven MWA were performed in porcine liver in vivo with a microwave generator (928 MHz; energy input 24 kJ). CECT was performed post-interventionally. Livers were explanted and ablations were bisected immediately after ablation. Samples were histologically analyzed after vital staining (NADH-diaphorase). Ablation zones were histologically and macroscopically outlined. We correlated histologic findings, macroscopic images and CECT.Results: Three ablation zones were identified in histological and macroscopic findings. Only one ablation zone could be depicted in CECT. Close conformity was observed between histological and macroscopic findings. The ablation zone depicted in CECT overestimated the histological avital central zone and inner red zone (p < = .01). No differences were found between CECT and the histological outer red zone (p > .05).Conclusions: Immediate post-interventional CECT overestimated the clinically relevant zone of complete cell ablation after MWA in porcine liver in vivo. This entails the risk of incomplete tumor ablation and could lead to tumor recurrence.

Comparison of different 4D CT-Perfusion algorithms to visualize lesions after microwave ablation in an in vivo porcine model.

Background: Accurate lesion visualization after microwave ablation (MWA) remains a challenge. Computed tomography perfusion (CTP) has been proposed to improve visualization, but it was shown that different perfusion-models delivered different results on the same data set.Purpose: Comparison of different perfusion algorithms and identification of the algorithm enables for the best imaging of lesion after hepatic MWA.Materials and methods: 10 MWA with consecutive CTP were performed in healthy pigs. Parameter-maps were generated using a single-input-dual-compartment-model with Patlak's algorithm (PM), a dual-input-maximum-slope-model (DIMS), a dual-input-one-compartment-model (DIOC), a single-(SIDC) and dual-input-deconvolution-model (DIDC). Parameter-maps for hepatic arterial (AF) and portal venous blood flow (PF), mean transit time, hepatic blood volume (HBV) and capillary permeability were compared regarding the values of the normal liver tissue (NLT), lesion, contrast- and signal-to-noise ratios (SNR, CNR) and inter- and intrarater-reliability using the intraclass correlation coefficient, Bland-Altman plots and linear regression.Results: Perfusion values differed between algorithms with especially large fluctuations for the DIOC. A reliable differentiation of lesion margin appears feasible with parameter-maps of PF and HBV for most algorithms, except for the DIOC due to large fluctuations in PF. All algorithms allowed for a demarcation of the central necrotic zone based on hepatic AF and HBV. The DIDC showed the highest CNR and the best inter- and intrarater reliability.Conclusion: The DIDC appears to be the most feasible model to visualize margins and necrosis zones after microwave ablation, but due to high computational demand, a single input deconvolution algorithm might be preferable in clinical practice.

Analysis of the First 217 Appendectomies of the German NOTES Registry.

OBJECTIVE: To analyze the feasibility and safety of Natural Orifice Transluminal Endoscopic Surgery (NOTES) appendectomy, and to analyze separately the transvaginal appendectomy (TVAE) and the transgastric appendectomy (TGAE) procedures. BACKGROUND: Laparoscopic appendectomy has rare but relevant complications, namely incisional hernias and neuralgia at the trocar sites, which can potentially be avoided by the NOTES techniques. METHODS: The first 217 data sets of the largest NOTES registry worldwide-the German NOTES registry-were analyzed with respect to demographic data, procedural data, and short-term outcomes. Furthermore, TVAEs were compared with TGAEs. RESULTS: Almost all procedures were performed in hybrid technique (median of percutaneous trocars: 1). Median age (TVAE: 30.5 yrs vs TGAE: 25 yrs; P < 0.017), body mass index (TVAE: 22.8 kg/m vs TGAE: 24.1 kg/m; P < 0.016), and American Society of Anesthesiologists (ASA) classification (I/II/III; TVAE: 57.1%/41.8%/1.0% vs TGAE: 27.8%/69.4%/2.8%; P < 0.003) significantly differed between both access techniques. Whereas the median number of percutaneous trocars (TVAE: 1 vs TGAE: 1; P < 0.450), the need of additional trocars (TVAE: 6.6% vs TGAE: 13.9%; P < 0.156), the intra, and also postoperative rate of complications (TVAE: 0%/5.5% vs TGAE: 0%/11.1%; P < 1.000/0.258), and the median postoperative hospital stay (TVAE: 3 d vs TGAE: 3 d; P < 0.152) were comparable; the median procedural time (TVAE: 35 minutes vs TGAE: 96 minutes; P < 0.001) and conversion to laparotomy rate (TVAE: 0% vs TGAE: 5.6%; P < 0.023) were significantly less after TVAE. CONCLUSIONS: The evaluation of the largest patient collective so far indicates that hybrid NOTES appendectomy is a safe procedure, with advantages for the transvaginal technique with respect to procedural time and conversion rate.

Determination of the electrical conductivity of human liver metastases: impact on therapy planning in the radiofrequency ablation of liver tumors.

Background Radiofrequency ablation is used to induce thermal necrosis in the treatment of liver metastases. The specific electrical conductivity of a liver metastasis has a distinct influence on the heat formation and resulting tumor ablation within the tissue. Purpose To examine the electrical conductivity σ of human colorectal liver metastases and of tumor-free liver tissue in surgical specimens. Material and Methods Surgical specimens from patients with resectable colorectal liver metastases were used for measurements (size of metastases <30 mm). A four-needle measuring probe was used to determine the electrical conductivity σ of human colorectal liver metastasis (n = 8) and tumor-free liver tissue (n = 5) in a total of five patients. All measurements were performed at 470 kHz, which is the relevant frequency for radiofrequency ablation. The tissue temperature was also measured. Hepatic resections were performed in accordance with common surgical standards. Measurements were performed in the operating theater immediately after resection. Results The median electrical conductivity σ was 0.57 S/m in human colorectal liver metastases at a median temperature of 35.1℃ and 0.35 S/m in tumor-free liver tissue at a median temperature of 34.9℃. The electrical conductivity was significantly higher in tumor tissue than in tumor-free liver tissue ( P = 0.005). There were no differences in tissue temperature between the two groups ( P = 0.883). Conclusion The electrical conductivity is significantly higher in human colorectal liver metastases than in tumor-free liver tissue at a frequency of 470 kHz.

Finding Optimal Ablation Parameters for Multipolar Radiofrequency Ablation.

PURPOSE: Radiofrequency ablation (RFA) for primary liver tumors and liver metastases is restricted by a limited ablation size. Multipolar RFA is a technical advancement of RFA, which is able to achieve larger ablations. The aim of this ex vivo study was to determine optimal ablation parameters for multipolar RFA depending on applicator distance and energy input. METHODS: RFA was carried out ex vivo in porcine livers with three internally cooled, bipolar applicators in multipolar ablation mode. Three different applicator distances were used and five different energy inputs were examined. Ablation zones were sliced along the cross-sectional area at the largest ablation diameter, orthogonally to the applicators. These slices were digitally measured and analyzed. RESULTS: Sixty RFA were carried out. A limited growth of ablation area was seen in all test series. This increase was dependent on ablation time, but not on applicator distance. A steady state between energy input and energy loss was not observed. A saturation of the minimum radius of the ablation zone was reached. Differences in ablation radius between the three test series were seen for lowest and highest energy input ( P < .05). No differences were seen for medium amounts of energy ( P > .05). CONCLUSIONS: The ablation parameters applicator distance and energy input can be chosen in such a way, that minor deviations of the preplanned ablation parameters have no influence on the size of the ablation area.

The vascular cooling effect in hepatic multipolar radiofrequency ablation leads to incomplete ablation ex vivo.

PURPOSE: Major limitations of conventional RFA are vascular cooling effects. However, vascular cooling effects are supposed to be less pronounced in multipolar RFA. The objective of this ex vivo study was a systematic evaluation of the vascular cooling effects in multipolar RFA. MATERIALS AND METHODS: Multipolar RFA with three bipolar RFA applicators was performed ex vivo in porcine liver (applicator distance 20 mm, energy input 40 kJ). A saline-perfused glass tube ('vessel') was placed parallel to the applicators in order to simulate a natural liver vessel. Five applicator-to-vessel geometries were tested. A liquid-filled glass tube without perfusion was used as a dry run. Ablations were orthogonally cut to the applicators at a defined height. Cooling effects were analysed qualitatively and quantitatively along these cross sectional areas. RESULTS: Thirty-six ablations were performed. A cooling effect could be seen in all ablations with perfused vessels compared to the dry run. While this cooling effect did not have any influence on the ablation areas (859-1072 mm(2) versus 958 mm(2) in the dry run, p > 0.05), it had a distinctive impact on ablation shape. A vascular cooling effect could be observed in all ablations with perfusion directly around the vessel independent of the applicator position compared to the dry run (p < 0.01). CONCLUSIONS: A vascular cooling effect occurred in all multipolar RFA with simulated liver vessels ex vivo independent of the applicator-to-vessel geometry. While the cooling effect did not influence the total ablation area, it had a distinctive impact on the ablation shape.

Natural Orifice Transluminal Endoscopic Surgery (NOTES) for colon resections--analysis of the first 139 patients of the German NOTES Registry (GNR).

BACKGROUND: The German NOTES registry (GNR) is the largest published database for natural orifice transluminal endoscopic surgery (NOTES) worldwide. Although transvaginal cholecystectomy is the most frequent procedure in the GNR, the number of colorectal resections is increasing. The objective of this study was to analyze the first 139 colonic procedures of the GNR. METHODS: All colonic procedures from the GNR were analyzed regarding patient- and therapy-related parameters. A multivariate analysis was conducted for transvaginal sigmoid resections regarding procedural time, hospital stay, conversion rate, and rate of complications. RESULTS: From October 2008 to January 2013, 139 colon NOTES procedures (12 male, 127 female) were registered. Main diagnoses were sigmoid diverticulitis (85.6 %), colon carcinoma (9.4 %), and ulcerative colitis (3.6 %). Sigmoid resections (87.1 %), proctocolectomies (3.6 %), right-sided resections (2.9 %), left-sided resections (3.6 %), segmental resections (2.2 %), and 1 ileocecal resection (0.7 %) were performed. All procedures were conducted in transvaginal (87.8 %) or transrectal (12.2 %) hybrid technique, with a median of 3 percutaneous trocars. Conversions to laparoscopic technique were necessary in 3.6 % (none to conventional technique). Intraoperative complications were recorded in 2.9 % and postoperative complications in 12.2 %. The institutional case number in transvaginal sigmoid resections correlated negatively with procedural time (p = 0.041) and the number of percutaneous trocars (p = 0.002). CONCLUSION: The analysis of the first 139 colon NOTES operations of the GNR shows the feasibility of co on operations in hybrid technique, especially for transvaginal sigmoid resection as the most frequent procedure.

Educational and training aspects of new surgical techniques: experience with the endoscopic­laparoscopic interdisciplinary training entity (ELITE) model in training for a natural orifice translumenal endoscopic surgery (NOTES) approach to appendectomy.

BACKGROUND: Natural orifice translumenal endoscopic surgery (NOTES) is a new surgical concept that requires training before it is introduced into clinical practice. The endoscopic­laparoscopic interdisciplinary training entity (ELITE) is a training model for NOTES interventions. The latest research has concentrated on new materials for organs with realistic optical and haptic characteristics and the possibility of high-frequency dissection. This study aimed to assess both the ELITE model in a surgical training course and the construct validity of a newly developed NOTES appendectomy scenario. METHODS: The 70 attendees of the 2010 Practical Course for Visceral Surgery (Warnemuende, Germany) took part in the study and performed a NOTES appendectomy via a transsigmoidal access. The primary end point was the total time required for the appendectomy, including retrieval of the appendix. Subjective evaluation of the model was performed using a questionnaire. Subgroups were analyzed according to laparoscopic and endoscopic experience. RESULTS: The participants with endoscopic or laparoscopic experience completed the task significantly faster than the inexperienced participants (p = 0.009 and 0.019, respectively). Endoscopic experience was the strongest influencing factor, whereas laparoscopic experience had limited impact on the participants with previous endoscopic experience. As shown by the findings, 87.3% of the participants stated that the ELITE model was suitable for the NOTES training scenario, and 88.7% found the newly developed model anatomically realistic. CONCLUSIONS: This study was able to establish face and construct validity for the ELITE model with a large group of surgeons. The ELITE model seems to be well suited for the training of NOTES as a new surgical technique in an established gastrointestinal surgery skills course.

Prognostic value of primary tumor sidedness in patients with non-metastatic IBD related CRC - Is it the exception to the rule?

BACKGROUND: Although primary tumor sidedness (PTS) has a known prognostic role in sporadic colorectal cancer (CRC), its role in Inflammatory Bowel Disease related CRC (IBD-CRC) is largely unknown. Thus, we aimed to evaluate the prognostic role of PTS in patients with IBD-CRC. METHODS: All eligible patients with surgically treated, non-metastatic IBD-CRC were retrospectively identified from institutional databases at ten European and Asian academic centers. Long term endpoints included recurrence-free (RFS) and overall survival (OS). Multivariable Cox proportional hazard regression as well as propensity score analyses were performed to evaluate whether PTS was significantly associated with RFS and OS. RESULTS: A total of 213 patients were included in the analysis, of which 32.4% had right-sided (RS) tumors and 67.6% had left-sided (LS) tumors. PTS was not associated with OS and RFS even on univariable analysis (5-year OS for RS vs LS tumors was 68.0% vs 77.3%, respectively, p = 0.31; 5-year RFS for RS vs LS tumors was 62.8% vs 65.4%, respectively, p = 0.51). Similarly, PTS was not associated with OS and RFS on propensity score matched analysis (5-year OS for RS vs LS tumors was 82.9% vs 91.3%, p = 0.79; 5-year RFS for RS vs LS tumors was 85.1% vs 81.5%, p = 0.69). These results were maintained when OS and RFS were calculated in patients with RS vs LS tumors after excluding patients with rectal tumors (5-year OS for RS vs LS tumors was 68.0% vs 77.2%, respectively, p = 0.38; 5-year RFS for RS vs LS tumors was 62.8% vs 59.2%, respectively, p = 0.98). CONCLUSIONS: In contrast to sporadic CRC, PTS does not appear to have a prognostic role in IBD-CRC.

Bipolar radiofrequency ablation for nodular thyroid disease--ex vivo and in vivo evaluation of a dose-response relationship.

BACKGROUND: The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like radiofrequency ablation (rfA) are increasingly used to treat tumors of parenchymatous organs, and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for rfA of thyroid nodules. MATERIAL AND METHODS: Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n=110) and in vivo (n=10) using a bipolar radiofrequency system; rf was applied in a power range of 10-20 watts. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The transversal and axial lesion diameters were measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed. RESULTS: The inducible lesion volumes were between 0.91±0.71 cm(3) at 20W and 2.80±0.85 cm(3) at 14W. The maximum temperatures after rf ablation were between 44.0±9.7°C and 61.6±13.9°C at a distance of 5 mm and between 30.0±8.6°C and 53.5±8.6°C at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) dehydrogenase activity in thermal lesions as a sign of irreversible cell damage. CONCLUSION: This study is the first to demonstrate a dose-response relationship for rfA of thyroid tissue. rfA is suitable for singular thyroid nodules and induces reproducible, clinically relevant lesions with irreversible cell damage in an appropriate application time.

Long-term outcome after conservative and surgical treatment of acute sigmoid diverticulitis.

PURPOSE: This study was designed to compare the long-term outcome of patients treated with conservative versus surgical treatment for acute sigmoid diverticulitis (SD). PATIENTS AND METHODS: Consecutive admissions of all patients with acute SD were prospectively recruited from January 2004 to June 2007. In June 2008, all patients were contacted using a standardized questionnaire. Outcomes were compared based on initial therapy (conservative vs. surgical). Furthermore, multiple logistic regression was used to identify risk factors for recurrence of SD. RESULTS: A total of 210 patients were included in the study. One hundred fifty-three patients were reached for follow-up: 70 (45.8%) presented with their first episode, and 83 (54.2%) had a prior history of SD. The median follow-up was 32 months (range 12-52). Thirteen (32.5%) of 40 conservatively treated patients and four (3.5%) of 113 surgically treated patients had a recurrence of SD (p < 0.001) during follow-up. One patient (2.5%) required emergency surgery after conservative treatment due to free perforation (p = 0.567). Treatment groups did not differ in age, gender, and inflammatory parameters, but conservatively treated patients had a significantly higher comorbidity (>2 disorders; p = 0.038) and less frequently a severe SD (p = 0.022) at the index admission. Recurrent episode of SD, covered perforated SD, and conservative treatment were identified as risk factors for recurrence of SD on multiple logistic regression. CONCLUSIONS: Surgical treatment of acute SD is more effective in preventing an eventual relapse of SD than conservative treatment, particularly in patients with recurrent and severe diverticulitis. The necessity for an emergency operation during follow-up is low and did not differ between the two treatment groups. The initial clinical presentation of SD is not a strong predictor of recurrence.

Effectiveness of various thermal ablation techniques for the treatment of nodular thyroid disease--comparison of laser-induced thermotherapy and bipolar radiofrequency ablation.

Alternative minimally invasive treatment options such as radiofrequency ablation (RFA) or laser-induced thermotherapy (LITT) are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions. So far, studies have not been able to show a secure advantage for neither LITT nor RFA. The aim of this study was to compare the two ablation procedures in terms of their effectiveness. Thermal lesions were induced in porcine thyroid glands either by LITT or bipolar RFA ex vivo (n = 110 each) and in vivo (n = 10 each) using power settings between 10 and 20 W. Temperature spread during application was documented in 5- and 10-mm distance of the applicator. Postinterventional lesion diameters were measured and lesion size was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed in vivo. Lesion volumes induced by LITT ranged between 0.74 ± 0.18 cm(3) (10 W) and 3.80 ± 0.41 cm(3) (20 W) with a maximum of 5.13 ± 0.16 cm(3) at 18 W. The inducible lesion volumes by RFA were between 2.43 ± 0.68 cm(3) (10 W) and 0.91 ± 0.71 cm(3) (20 W) with a maximum of 2.80 ± 0.85 cm(3) at 14 W. The maximum temperatures were 112.9 ± 9.2°C (LITT) and 61.6 ± 13.9°C (RFA) at a distance of 5 mm and 73.2 ± 6.7°C (LITT) and 53.5 ± 8.6°C (RFA) at a distance of 10 mm. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage both for LITT and RFA. This study is the first to compare the effectiveness of laser-induced thermotherapy and radiofrequency ablation of thyroid tissue. LITT as well as RFA are suitable for singular thyroid nodules and induces reproducible clinically relevant lesions in an appropriate application time. The maximum inducible lesion volumes by LITT are significantly larger than by RFA with the devices used herein.

Safety of anastomoses in colorectal cancer surgery in octogenarians: a prospective cohort study with propensity score matching.

BACKGROUND: Up to 20 per cent of all operations for patients with colorectal cancer (CRC) are performed in octogenarians. Anastomotic leakage is a leading cause of morbidity and death after resection for CRC. The aim of this study was to assess the rate of anastomosis creation, the risk of anastomotic leakage and death in surgery for left-sided CRC in elderly patients. METHODS: This prospective cohort study compared patients less than 80 and 80 or more years with left-sided CRC resection performed between 2013 and 2019. Data were provided from a risk-adjusted surgical quality-assessment system with 219 participating centres in Germany. Outcome measures were the rate of anastomoses, anastomotic leakages, death at 30 days and 2-year overall survival (OS). Propensity score matching was used to control for selection bias and compare subgroups of patients of less than 80 and 80 or more years. RESULTS: Out of 18 959 patients, some 3169 (16.7 per cent) were octogenarians. Octogenarians were less likely to receive anastomoses (82.0 versus 92.9 per cent, P < 0.001; odds ratio 0.50 (95 per cent c.i. 0.44 to 0.58), P < 0.001). The rate of anastomotic leakages did not differ between age groups (8.6 versus 9.7 per cent, P = 0.084), but 30-day mortality rate after leakage was significantly higher in octogenarians (15.8 versus 3.5 per cent, P < 0.001). Overall, anastomotic leakage was the strongest predictor for death (odds ratio 4.95 (95 per cent c.i. 3.66 to 6.66), P < 0.001). In the subgroup with no leakage, octogenarians had a lower 2-year OS rate than younger patients (71 versus 87 per cent, P < 0.001), and in the population with anastomotic leakage, the 2-year OS was 80 per cent in younger and 43 per cent in elderly patients (P < 0.001). After propensity score matching, older age remained predictive for not receiving an anastomosis (odds ratio 0.54 (95 per cent c.i. 0.46 to 0.63), P < 0.001) and for death (odds ratio 2.60 (95 per cent c.i. 1.78 to 3.84), P < 0.001), but not for the occurrence of leakages (odds ratio 0.94 (95 per cent c.i. 0.76 to 1.15), P = 0.524). CONCLUSION: Anastomotic leakage is not more common in octogenarians, but an age of 80 years or older is an independent factor for not receiving an anastomosis in surgery for left-sided CRC. The mortality rate in the case of leakage in octogenarians was reported to exceed 15 per cent.

Increased proinflammatory cytokines in mesenteric fat in major surgery and Crohn's disease.

BACKGROUND: Proinflammatory cytokines play an important role in abdominal surgery and are often associated with the development of postoperative ileus, especially in Crohn's disease. The aim of this study was to investigate proinflammatory cytokine levels in mesenteric fat in Crohn's disease and patients without Crohn's disease. METHODS: Human mesenteric tissue specimen were divided into 3 patient groups (n = 10 each): minor surgery (laparoscopic cholecystectomy), major surgery (colectomy) in patients without Crohn's disease, and major surgery (colectomy) in patients with Crohn's disease. Levels of interleukin 6, interleukin 1-ß, and tumor necrosis factor α were determined by cytometric bead array, enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction. The Kruskal-Wallis and the Mann-Whitney U test were used to compare continuous variables. For categorical variables, the χ2 test or Fisher exact test was used. RESULTS: In minor surgery, cytokines levels of interleukin 6, interleukin 1-ß and Tumor necrosis factor α were low (ie, interleukin 6: 1 pg/mL [0-36], interleukin 1-ß: 0 fg/mL [0-18], tumor necrosis factor α: 157 fg/mL [91-237]) compared with major surgery in patients with and without Crohn's disease. Cytokines were significantly higher in major surgery (ie, interleukin 6: 147 pg/mL [29-347], interleukin 1-ß: 660 fg/mL [0-2580], tumor necrosis factor α: 532 fg/mL [289-1647]; P = .02 and major surgery with CD (cytometric bead array: interleukin 6: 94 pg/mL [24-627], interleukin 1-ß: 708 fg/mL [0-1664], tumor necrosis factor α: 733 fg/mL [209-1,354]; P < .05). Cytokine levels in major surgery with Crohn's disease showed a further increase of interleukin 6 in polymerase chain reaction in comparison to major surgery in patients without Crohn's disease (1.2 vs 4, P = .04). CONCLUSION: Proinflammatory cytokines are increased in the mesenteric fat in major operations compared to minor operations, which indicates local mesenteric inflammation. In Crohn's disease, levels of proinflammatory cytokines are even higher, which may put the patients at risk for postoperative ileus.