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.

Systematic review of robotic low anterior resection for rectal cancer.

BACKGROUND: Potential advantages of robotic surgery, such as 3-dimensional high-definition vision, wrist-like movements of instruments, stable camera holding, motion filter for tremor-free surgery, and improved ergonomics, may provide better clinical, oncological, and functional outcomes in rectal cancer surgery, as suggested in many comparative studies. However, there has not been a systematic review specific to LAR/TME for rectal cancer that includes both robotic versus laparoscopic and robotic versus open comparative studies. METHODS: The PubMed and Scopus databases were systematically searched in a two-step process, first for all robotic publications, and then within those results, for studies that compared perioperative, oncologic, or functional outcomes of robotic versus laparoscopic or open LAR/TME. Randomized controlled trials, systematic reviews, and independent database population studies were included in the analysis. RESULTS: Thirteen publications reporting on 24,526 patients met the inclusion criteria. Two studies compared robotic and open surgery, ten compared robotic and laparoscopic surgery, and one study compared all three. Robotic surgery resulted in increased operating times, reduced blood loss, fewer transfusions, shorter hospital stay, and comparable oncologic outcomes versus open surgery, and reduced conversion and impotency rates versus laparoscopic surgery. CONCLUSIONS: Robotic surgery is comparable to open and laparoscopic surgery concerning oncologic outcomes and seems to provide some clinical and functional benefits, although evidence is limited.

Surgical Management of Iatrogenic Perforation of the Gastrointestinal Tract: 15 Years of Experience in a Single Center.

BACKGROUND: Gastrointestinal (GI) tract perforation during endoscopy is a rare but severe complication. The aim of this study was to determine predictors of morbidity and mortality after iatrogenic endoscopic perforation. MATERIALS AND METHODS: All cases with iatrogenic endoscopic perforation receiving surgery at a tertiary referral center in a 15-year period (2000-2015) were retrospectively analyzed. Demographics, type of endoscopy, site of perforation, operative procedure, morbidity and mortality were analyzed. Multiple logistic regression was used to identify parameters predicting survival. RESULTS: A total of 106.492 endoscopies were performed, and 82 (0.08%) patients were diagnosed with GI perforation. Most perforations (63.4%) occurred in the lower GI tract, compared to 36.6% in the upper GI tract. In 21 cases (25%), perforation was noticed during endoscopy, whereas 61 perforations (75%) were diagnosed during the further clinical course. Operative care was applied within 24 h in 61%. Surgery of perforations was almost completely performed maintaining the intestinal continuity (68%), whereas diversion was performed in 32%. Mortality was associated with age above 70 (OR 4.89, p = 0.027), ASA class > 3 (OR 4.08, p = 0.018), delayed surgery later than 24 h after perforation (OR 5.9, p = 0.015), peritonitis/mediastinitis intraoperatively (OR 4.68, p = 0.031) and severe postoperative complications with a Clavien-Dindo grade ≥III (OR 5.12, p = 0.023). CONCLUSION: The prevalence of iatrogenic endoscopic perforation is low, although it is associated with a serious impact on morbidity and mortality. Delayed management worsens prognosis. To achieve successful management of endoscopic perforations, early diagnosis is essential in cases of deviation from the normal post-interventional course, especially in elderly.

Bipolar radio-frequency-induced thermofusion of intestinal tissue - In vivo evaluation of a new fusion technique in an experimental study.

PURPOSE: Bipolar radio-frequency-induced thermofusion (BiRTh) of intestinal tissue might replace conventional stapling devices which are associated with technical and functional complications. Previous results of our study group confirmed the feasibility to fuse intestinal tissue using BiRTh-induced thermofusion ex vivo. The aim of this study was now to evaluate the efficacy of fusing intestinal tissue in vivo by BiRTh-induced thermofusion. MATERIALS AND METHODS: In male Wistar rats a blind bowel originating from the caecum was closed either by BiRTh (n = 24) or conventional suture (n = 16). At 6 h, 48 h, 4 days, and 2 weeks after the procedure caecum bursting pressure was measured to compare both groups. RESULTS: In total 18 of 21 (85.7%) thermofused and 15 of 16 (93.7%) sutured cecal stumps were primarily tight and leakage-proof (p > 0.05). The operative time was comparable in both groups without significant differences. Both groups showed increases in bursting pressure over the post-operative period. The mean bursting pressure for thermofusion was 47.8, 48.3, 55.2, and 68.0 mmHg, compared to 69.8, 51.5, 70.0 and 71.0 mmHg in the hand-sutured group (p > 0.05) after 6 h, 48 h, 4 days, and 2 weeks, respectively. CONCLUSION: These results suggest that BiRTh-induced thermofusion is a safe and feasible method for fusing intestinal tissue in this experimental in vivo model and could be an innovative approach for achieving gastrointestinal anastomoses.

Hepatic arterial infusion (HAI) with PEGylated liposomes containing 5-FU improves tumor control of liver metastases in a rat model.

PURPOSE: To investigate the cytostatic effect of 5-fluorouracil (5-FU) encapsulated in polyethylene glycol (PEG) liposomes with or without degradable starch microspheres (DSM) in a long-term trial using a rat liver tumor model. MATERIALS AND METHODS: The cytostatics were applied once either as a hepatic arterial infusion (HAI) or were systemically infused via the tail vein. Seven groups were compared with respect to tumor growth and survival times: 5-FU HAI (group I), 5-FU + DSM HAI (group II), PEG-5-FU HAI (group III), PEG-5-FU + DSM HAI (group IV), NaCl HAI (group V), 5-FU i.v. (group VI), and PEG-5-FU i.v. (group VII). RESULTS: Seven and 14 days after treatment in groups III and IV, only group IV had significantly inhibited tumor growth on day 21 compared to the groups treated intravenously. On day 28, none of the animals from the intravenously treated groups were still alive compared to a significantly longer survival time of 6 and 8 weeks in groups III and IV. CONCLUSION: Locoregional therapy with 5-fluorouracil encapsulated in PEGylated liposomes may further improve the treatment success with longer-lasting tumor regression and prolonged survival times.

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.

Clostridium difficile infection of the small bowel--two case reports with a literature survey.

INTRODUCTION: Diseases associated with Clostridium difficile range from antibiotic-related diarrhea to pseudomembranous enterocolitis, and are serious nosocomial infections with high morbidity and mortality. The C. difficile infection has thus far been regarded as a disease typically affecting the colon. However, the literature contains an increasing number of reports describing infections of the small bowel with fulminant clinical courses and high mortality rates of 60-83%. We think this situation is not very well known. METHODS: We present two cases of confirmed C. difficile enteritis and a survey of the literature. CONCLUSION: C. difficile enteritis is characterized by a rising incidence, a sometimes fulminant clinical course, and high mortality rates. Early diagnosis of the disease by toxin detection and endoscopy is of paramount importance and can play a substantial role in improving outcomes.

In vivo validation of a therapy planning system for laser-induced thermotherapy (LITT) of liver malignancies.

PURPOSE: In situ ablation is increasingly being used for the treatment of liver malignancies. The application of these techniques is limited by the lack of a precise prediction of the destruction volume. This holds especially true in anatomically difficult situations, such as metastases in the vicinity of larger liver vessels. We developed a three-dimensional (3D) planning system for laser-induced thermotherapy (LITT) of liver tumors. The aim of the study was to validate the system for calculation of the destruction volume. METHODS: LITT (28 W, 20 min) was performed in close contact to major hepatic vessels in six pigs. After explantation of the liver, the coagulation area was documented. The liver and its vascular structures were segmented from a pre-interventional CT scan. Therapy planning was carried out including the cooling effect of adjacent liver vessels. The lesions in vivo and the simulated lesions were compared with a morphometric analysis. RESULTS: The volume of lesions in vivo was 6,568.3 ± 3,245.9 mm(3), which was not different to the simulation result of 6,935.2 ± 2,538.5 mm(3) (P = 0.937). The morphometric analysis showed a sensitivity of the system of 0.896 ± 0.093 (correct prediction of destructed tissue). The specificity was 0.858 ± 0.090 (correct prediction of vital tissue). CONCLUSIONS: A 3D computer planning system for the prediction of thermal lesions in LITT was developed. The calculation of the directional cooling effect of intrahepatic vessels is possible for the first time. The morphometric analysis showed a good correlation under clinical conditions. The pre-therapeutic calculation of the ablation zone might be a valuable tool for procedure planning.

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.

Bipolar radiofrequency-induced thermofusion of intestinal anastomoses--feasibility of a new anastomosis technique in porcine and rat colon.

PURPOSE: In recent years, vessel sealing has become a well-established method in surgical practice for sealing and transecting vessels. Since this technology depends on the fusion of collagen fibers abundantly present in the intestinal wall, it should also be possible to create intestinal anastomoses by thermofusion. Bipolar radiofrequency-induced thermofusion of intestinal tissue may replace traditionally used staples or sutures in the future. The aim of this study was to evaluate the feasibility of fusing intestinal tissue ex vivo by bipolar radiofrequency-induced thermofusion. MATERIALS AND METHODS: An experimental setup for temperature-controlled bipolar radiofrequency-induced thermofusion of porcine (n = 30) and rat (n = 18) intestinal tissue was developed. Colon samples were harvested and then anastomosed, altering compressive pressure to examine its influence on anastomotic bursting pressure during radiofrequency-induced anastomotic fusion. For comparison, mechanical stapler anastomoses of porcine colonic samples and conventional suturing of rat colonic samples identical to those used for fusion experiments were prepared, and burst pressure was measured. RESULTS: All thermofused colonic anastomoses were primarily tight and leakage proof. For porcine colonic samples, an optimal interval of compressive pressure (1,125 mN/mm(2)) with respect to a high amount of burst pressure (41 mmHg) was detected. The mean bursting pressure for mechanical stapler anastomosis was 60.7 mmHg and did not differ from the thermofusion (p = 0.15). Furthermore, the mean bursting pressure for thermofusion of rat colonic samples was up to 69.5 mmHg for a compressive pressure of 140 mN/mm(2). CONCLUSION: These results confirm the feasibility to create experimental intestinal anastomoses using bipolar radiofrequency-induced thermofusion. The stability of the induced thermofusion showed no differences when compared to that of conventional anastomoses. Bipolar radiofrequency-induced thermofusion of intestinal tissue represents an innovative approach for achieving gastrointestinal anastomoses.

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.

Assessment of Risk Factors for the Occurrence of a High-Output Ileostomy.

Background: Ileostomy is often required in patients undergoing bowel resections for inflammatory bowel diseases (IBD), colorectal cancer, and emergencies. Unfortunately, some patients develop a high-output stoma (HOS). This condition affects homeostasis and may be life threatening. We aimed to identify possible risk factors for the development of HOS. Patients and methods: From 2012 to 2018, 296 patients who underwent ileostomy at Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin were retrospectively analyzed. Emergency operations were included. Diverting ileostomy, end ileostomies and anastomotic stomata with at least part ileum, were examined. HOS was defined as stoma output of more than 1,000 mL per day for more than 3 days. Univariate and multivariable analyses were used to detect potential risk factors for the development of HOS. Results: 41 of 296 patients developed HOS (13.9%). Mortality was 0.3%. In the univariate analysis, age (p < 0.002), diagnosis (Crohn's disease, p = 0.005), arterial hypertension (p = 0.023), surgical procedure (right-sided colectomy, small bowel resection, p < 0.001), open technique (p < 0.002), emergencies (p = 0.014), and anastomotic ileostomy (p < 0.001) were identified as risk factors. In the multivariable logistic regression, older age, diagnosis (Crohn's disease) and surgical procedure (right-sided colectomy, separate ileostomy, small bowel resection) remained significant risk factors. Conclusion: The occurrence of HOS is a relevant problem after ileostomy. The identification of risk factors for a high-output may be helpful for monitoring, early diagnosis and initiation of therapy as well as in the planning of close follow-up care.

Microscopic inflammation in ileocecal specimen does not correspond to a higher anastomotic leakage rate after ileocecal resection in Crohn's disease.

BACKGROUND: Patients with Crohn's disease suffer from a higher rate of anastomotic leakages after ileocecal resection than patients without Crohn's disease. Our hypothesis was that microscopic inflammation at the resection margins of ileocecal resections in Crohn's disease increases the rate of anastomotic leakages. PATIENTS AND METHODS: In a retrospective cohort study, 130 patients with Crohn's disease that underwent ileocecal resection between 2015 and 2019, were analyzed. Anastomotic leakage was the primary outcome parameter. Inflammation at the resection margin was characterized as "inflammation at proximal resection margin", "inflammation at distal resection margin" or "inflammation at both ends". RESULTS: 46 patients (35.4%) showed microscopic inflammation at the resection margins. 17 patients (13.1%) developed anastomotic leakage. No difference in the rate of anastomotic leakages was found for proximally affected resection margins (no anastomotic leakage vs. anastomotic leakage: 20.3 vs. 35.3%, p = 0.17), distally affected resection margins (2.7 vs. 5.9%, p = 0.47) or inflammation at both ends (9.7 vs. 11.8%, p = 0.80). No effect on the anastomotic leakage rate was found for preoperative hemoglobin concentration (no anastomotic leakage vs. anastomotic leakage: 12.3 vs. 13.5 g/dl, p = 0.26), perioperative immunosuppressive medication (62.8 vs. 52.9%, p = 0.30), BMI (21.8 vs. 22.4 m2/kg, p = 0.82), emergency operation (21.2 vs. 11.8%, p = 0.29), laparoscopic vs. open procedure (p = 0.58), diverting ileostomy (31.9 vs. 57.1%, p = 0.35) or the level of surgical training (staff surgeon: 80.5 vs. 76.5%, p = 0.45). CONCLUSION: Microscopic inflammation at the resection margins after ileocecal resection in Crohn's disease is common. Histologically inflamed resection margins do not appear to affect the rate of anastomotic leakages. Our data suggest that there is no need for extensive resections or frozen section to achieve microscopically inflammation-free resection margins.

The German registry for natural orifice translumenal endoscopic surgery: report of the first 551 patients.

OBJECTIVE: To analyze patient outcome in the first 14 months of the German natural orifice translumenal endoscopic surgery (NOTES) registry (GNR). SUMMARY BACKGROUND DATA: NOTES is a new surgical concept, which permits scarless intra-abdominal operations through natural orifices, such as the mouth, vagina, rectum, or urethra. The GNR was established as a nationwide outcome database to allow the monitoring and safe introduction of this technique in Germany. METHODS: The GNR was designed as a voluntary database with online access. All surgeons in Germany who performed NOTES procedures were requested to participate in the registry. The GNR recorded demographical and therapy data as well as data on the postoperative course. RESULTS: A total of 572 target organs were operated in 551 patients. Cholecystectomies accounted for 85.3% of all NOTES procedures. All procedures were performed in female patients using transvaginal hybrid technique. Complications occurred in 3.1% of all patients, conversions to laparoscopy or open surgery in 4.9%. In cholecystectomies, institutional case volume, obesity, and age had substantial effect on conversion rate, operation length, and length of hospital stay, but no effect on complications. CONCLUSIONS: Despite the fact that NOTES has just recently been introduced, the technique has already gained considerable clinical application. Transvaginal hybrid NOTES cholecystectomy is a practicable and safe alternative to laparoscopic resection even in obese or older patients.

Fluid resuscitation with human albumin or hydroxyethyl starch--are there differences in the healing of experimental intestinal anastomoses?

OBJECTIVES: Restoration of the macro- and microcirculation is important for the healing of gastrointestinal anastomoses. Colloids and crystalloids are widely used for blood volume therapy. We evaluated the effects of human albumin, hydroxyethyl starch (HES) 130/0.4 and saline on the microcirculation and on wound healing in colon anastomoses in rats. MATERIAL AND METHODS: Male Wistar rats received a colonic end-to-end anastomosis. The animals were randomized into three groups and a single 3-ml dose of either 20% human albumin, 6% HES 130/0.4 or 0.9% saline was applied intravenously. Six, 24, 48, 96 h and 2 weeks after the procedure, 10 animals per group were reanesthetized. Measurements of capillary blood flow, vessel permeability and anastomosis bursting pressure were performed. The amounts of vascular endothelial growth factor (VEGF) and IL-6 in the plasma were determined by enzyme-linked immunosorbent assays, and the mRNA levels of VEGF and collagen types I and III were measured by real-time polymerase chain reaction. RESULTS: No significant differences were found between albumin, HES 130/0.4 and saline in capillary blood flow, vessel permeability and anastomotic bursting pressure in this rat model. Concentrations of collagen I and III mRNA were significantly elevated after 96 h in animals that had received HES 130/0.4 or albumin. RNA and protein levels of VEGF and interleukin-6 were unaffected by therapy. CONCLUSIONS: Human albumin, which is still widely used in the clinical setting, had no advantage over HES 130/0.4 and saline with regard to anastomotic healing in this animal model. Nevertheless, we prefer HES 130/0.4 because it is more effective for volume therapy than saline and has a better availability and is less expensive than human albumin.

Pilot study of bipolar radiofrequency-induced anastomotic thermofusion-exploration of therapy parameters ex vivo.

PURPOSE: Vessel sealing has been well-established in surgical practice in recent years. Bipolar radiofrequency-induced thermofusion (BIRTH) of intestinal tissue might replace traditionally used staples or sutures in the near future. In this experimental study, the influence of compressive pressure, fusion temperature, and duration of heating on the quality of intestinal anastomosis was investigated to obtain the relevant major parameters for the in vivo use of this system. METHODS: An experimental setup for a closed-loop temperature-controlled bipolar radiofrequency-induced thermofusion of porcine intestinal tissue was developed. Twenty-four colon samples were harvested from nine different Saalower-Kräuter pigs and then anastomosed altering compressive pressure on five different levels to explore its influence on anastomotic bursting pressure. RESULTS: The anastomotic bursting strength depends on the compressive pressure applied to the colonic fusion site. An optimal interval of compressive pressure (CP = 1.125 N/mm(2)) in respect of a high amount of burst pressure was detected. A correlation (r = 0.54, p = 0.015) of burst pressure to delta compression indicated that increasing colonic wall thickness probably strengthens the anastomotic fusion. CONCLUSION: This study is a first step to enlighten the major parameters of tissue fusion, though effects and interactions of various main parameters of bipolar radiofrequency-induced thermofusion of colonic tissue remain unclear. Further studies exploring the main effects and interactions of tissue and process parameters to the quality of the fusion site have to follow.

Determination of the temperature-dependent electric conductivity of liver tissue ex vivo and in vivo: Importance for therapy planning for the radiofrequency ablation of liver tumours.

INTRODUCTION: Knowledge about the changes in the electric conductivity during the coagulation process of radiofrequency ablation of the liver is a prerequisite for the predictability of produceable thermonecrosis in the liver. MATERIALS AND METHODS: Continuous measurements of the electric conductivity sigma in ex vivo porcine liver (n = 25) were done during the coagulation and cooling process at the temperature range of the radiofrequency ablation at a frequency of 470 kHz relevant for the radiofrequency ablation. Measurements of the electric conductivity were performed in both perfused porcine liver (n = 3) and a human surgical specimen from a colorectal liver metastasis. RESULTS: At a body temperature of 37 degrees C, conductance sigma was 0.41 siemens per metre (0.32 S/m; 0.52 S/m). Conductance sigma increased continuously and uniformly at a temperature of 77 degrees C. Maximum conductance sigma with 0.79 S/m (0.7 S/m; 0.87 S/m) was reached at 80 degrees C. A continuous reduction of conductance was observed during the cooling phase. At 37 degrees C, the specific conductance sigma in the healthy perfused porcine liver was 0.52 S/m, 0.55 S/m and 0.57 S/m (mean 0.55 S/m). The electric conductivity of the human colorectal liver metastasis was clearly higher. CONCLUSION: Changes in the specific conductivity during the coagulation and the cooling phase play an important role for the produceable size of a coagulation necrosis and necessitates an adaptation of the therapy parameters during radiofrequency ablation.

Preoperative CT staging in sigmoid diverticulitis--does it correlate with intraoperative and histological findings?

PURPOSE: This study was designed to evaluate whether the computed tomography (CT) reflects the extent of the inflammation in sigmoid diverticulitis (SD) in order to draw conclusions for selecting the appropriate treatment. METHODS: Two hundred four patients who underwent resection for SD from January 2003 to December 2008 were included. The preoperative CT stage was compared with intraoperative and histological findings. Patients were classified into phlegmonous (Hansen-Stock IIa), abscess-forming (HS IIb), and free perforated (HS IIc) forms of SD. Patients with a recurrent type of diverticulitis were excluded. RESULTS: In the phlegmonous type (HS IIa; n = 75), we found a correlation with the preoperative stage in 52% (intraoperative) and 56% (histological), an understaging in 12% (intraoperative) and 11% (histological), and an overstaging in 36% (intraoperative) and 33% (histological). In the abscess-forming type (HS IIb, Hinchey I/II; n = 87), we found conformity in 92% (intraoperative) and 90% (histological), understaging in 3% (intraoperative) and 0% (histological), and overstaging in 5% (intraoperative) and 10% (histological). In the presence of a free perforation (HS IIc, Hinchey III/IV; n = 42), we saw conformity in 100% (intraoperative and histological). The positive predictive value for correctly diagnosing of phlegmonous type (HS IIa), abscess-forming type (HS IIb), and free perforation (HS IIc) by CT was intraoperatively (histologically) 52% (56), 92% (90), and 100% (100), respectively. CONCLUSIONS: The CT is one of the most accurate methods for staging in SD. However, in the phlegmonous type (HS IIa), it leads to an overestimation of the findings in every third patient. It must be clarified whether this pronounced low inflammation should really be regarded as a complicated form of SD. In contrast, the abscess-forming (HS IIb) and free perforated (HS IIc) type of complicated SD is very well reflected by CT.

Ex vivo and in vivo evaluation of laser-induced thermotherapy for nodular thyroid disease.

BACKGROUND AND OBJECTIVE: The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like laser-induced thermotherapy (LITT) 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 LITT of thyroid nodules. MATERIALS AND METHODS: Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n = 110) and in vivo (n = 10) using an Nd:YAG laser (1,064 nm). Laser energy was applied for 300 seconds in a power range of 10-20 W. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The lesions were longitudinally and transversally measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed. RESULTS: The maximum inducible lesion volumes were between 0.74 +/- 0.18 cm(3) at a laser power of 10 W and 3.80 +/- 0.41 cm(3) at 20 W. The maximum temperatures after ablation were between 72.9 +/- 2.9 degrees C (10 W) and 112.9 +/- 9.2 degrees C (20 W) at a distance of 5 mm and between 49.5 +/- 2.2 degrees C (10 W) and 73.2 +/- 6.7 degrees C (20 W) at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage. CONCLUSIONS: This study is the first to demonstrate a dose-response relationship for LITT of thyroid tissue. LITT is suitable for singular thyroid nodules and induces reproducible clinically relevant lesions with irreversible cell damage in an appropriate application time.