I-CARE-An Interaction System for the Individual Activation of People with Dementia.

I-CARE is a hand-held activation system that allows professional and informal caregivers to cognitively and socially activate people with dementia in joint activation sessions without special training or expertise. I-CARE consists of an easy-to-use tablet application that presents activation content and a server-based backend system that securely manages the contents and events of activation sessions. It tracks various sources of explicit and implicit feedback from user interactions and different sensors to estimate which content is successful in activating individual users. Over the course of use, I-CARE's recommendation system learns about the individual needs and resources of its users and automatically personalizes the activation content. In addition, information about past sessions can be retrieved such that activations seamlessly build on previous sessions while eligible stakeholders are informed about the current state of care and daily form of their protegees. In addition, caregivers can connect with supervisors and professionals through the I-CARE remote calling feature, to get activation sessions tracked in real time via audio and video support. In this way, I-CARE provides technical support for a decentralized and spontaneous formation of ad hoc activation groups and fosters tight engagement of the social network and caring community. By these means, I-CARE promotes new care infrastructures in the community and the neighborhood as well as relieves professional and informal caregivers.

Identification of BCL-XL as highly active survival factor and promising therapeutic target in colorectal cancer.

Since metastatic colorectal cancer (CRC) is a leading cause of cancer-related death, therapeutic approaches overcoming primary and acquired therapy resistance are an urgent medical need. In this study, the efficacy and toxicity of high-affinity inhibitors targeting antiapoptotic BCL-2 proteins (BCL-2, BCL-XL, and MCL-1) were evaluated. By RNA sequencing analysis of a pan-cancer cohort comprising >1500 patients and subsequent prediction of protein activity, BCL-XL was identified as the only antiapoptotic BCL-2 protein that is overactivated in CRC. Consistently, pharmacologic and genetic inhibition of BCL-XL induced apoptosis in human CRC cell lines. In a combined treatment approach, targeting BCL-XL augmented the efficacy of chemotherapy in vitro, in a murine CRC model, and in human ex vivo derived CRC tissue cultures. Collectively, these data show that targeting of BCL-XL is efficient and safe in preclinical CRC models, observations that pave the way for clinical translation.

Dissection with LigaSure Impact™ versus conventional resection in pylorus-preserving partial pancreatoduodenectomy (DISSECT): a single-institution randomized controlled trial.

PURPOSE: In partial pancreatoduodenectomy, appropriate effective hemostasis during dissection is of major importance for procedural flow, operation time, and postoperative outcome. As ligation, clipping, or suturing of blood vessels is time-consuming and numerous instrument changes are required, the primary aim of this randomized controlled trial was to assess whether LigaSure Impact™ exhibits benefits over named conventional dissection techniques in patients undergoing pylorus-preserving partial pancreatoduodenectomy. METHODS: This single-institution, randomized, superiority trial was performed between September 27, 2009, and February 24, 2012. Patients undergoing pylorus-preserving partial pancreatoduodenectomy were allocated to the study arms in a 1:1 ratio based on an unstratified block randomization with random block sizes to receive either dissection with LigaSure Impact™ or conventional dissection. The primary endpoint was operation time. Secondary endpoints included peri- and postoperative morbidity and mortality, intraoperative blood loss, and length of hospital stay. To observe a time reduction of 40 min, 51 patients per arm were required. The primary analysis was the intention to treat. RESULTS: The mean operation time did not differ between the Ligasure Impact™ (308 min; SD: 56 min; range: 155-455 min) and the conventional dissection (318 min; SD: 90 min, range: 175-550 min) (p = 0.531). Moreover, LigaSure Impact™ dissection did not show significant advantages over conventional dissection in terms of peri- and postoperative morbidity and mortality, intraoperative blood loss, or length of hospital stay. CONCLUSIONS: The application of LigaSure Impact™ dissection in pylorus-preserving partial pancreatoduodenectomy does not increase effectiveness and safety of dissection. TRIAL REGISTRATION: DRKS00000166.

Negative Pressure Wound Therapy vs Conventional Wound Treatment in Subcutaneous Abdominal Wound Healing Impairment: The SAWHI Randomized Clinical Trial.

Importance: Negative pressure wound therapy (NPWT) is an established treatment option, but there is no evidence of benefit for subcutaneous abdominal wound healing impairment (SAWHI). Objective: To evaluate the effectiveness and safety of NPWT for SAWHI after surgery in clinical practice. Design, Setting, and Participants: The multicenter, multinational, observer-blinded, randomized clinical SAWHI study enrolled patients between August 2, 2011, and January 31, 2018. The last follow-up date was June 11, 2018. The trial included 34 abdominal surgical departments of hospitals in Germany, Belgium, and the Netherlands, and 539 consecutive, compliant adult patients with SAWHI after surgery without fascia dehiscence were randomly assigned to the treatment arms in a 1:1 ratio stratified by study site and wound size using a centralized web-based tool. A total of 507 study participants (NPWT, 256; CWT, 251) were assessed for the primary end point in the modified intention-to-treat (ITT) population. Interventions: Negative pressure wound therapy and conventional wound treatment (CWT). Main Outcomes and Measures: The primary outcome was time until wound closure (delayed primary closure or by secondary intention) within 42 days. Safety analysis comprised the adverse events (AEs). Secondary outcomes included wound closure rate, quality of life (SF-36), pain, and patient satisfaction. Results: Of the 507 study participants included in the modified ITT population, 287 were men (56.6%) (NPWT, 155 [60.5%] and CWT, 132 [52.6%]) and 220 were women (43.4%) (NPWT, 101 [39.5%] and CWT 119 [47.4%]). The median (IQR) age of the participants was 66 (18) years in the NPWT arm and 66 (20) years in the CWT arm. Mean time to wound closure was significantly shorter in the NPWT arm (36.1 days) than in the CWT arm (39.1 days) (difference, 3.0 days; 95% CI 1.6-4.4; P < .001). Wound closure rate within 42 days was significantly higher with NPWT (35.9%) than with CWT (21.5%) (difference, 14.4%; 95% CI, 6.6%-22.2%; P < .001). In the therapy-compliant population, excluding study participants with unauthorized treatment changes (NPWT, 22; CWT, 50), the risk for wound-related AEs was higher in the NPWT arm (risk ratio, 1.51; 95% CI, 0.99-2.35). Conclusions and Relevance: Negative pressure wound therapy is an effective treatment option for SAWHI after surgery; however, it causes more wound-related AEs. Trial Registration: ClinicalTrials.gov Identifier: NCT01528033.

Primary Open Versus Closed Implantation Strategy for Totally Implantable Venous Access Ports: The Multicentre Randomized Controlled PORTAS-3 Trial (DRKS 00004900).

OBJECTIVES: PORTAS-3 was designed to compare the frequency of pneumothorax or haemothorax in a primary open versus closed strategy for port implantation. BACKGROUND DATA: The implantation strategy for totally implantable venous access ports with the optimal benefit/risk ratio remains unclear. METHODS: PORTAS-3 was a multicentre, randomized, controlled, parallel-group superiority trial. Adult patients with oncological disease scheduled for elective port implantation were randomized to a primary open or closed strategy. Primary endpoint was the rate of pneumothorax or haemothorax. Assuming a difference of 2.5% between the 2 groups, a sample size of 1154 patients was needed to prove superiority of the open group. A logistic regression model after the intention-to-treat principle was applied for analysis of the primary endpoint. RESULTS: Between November 9, 2014 and September 5, 2016, 1205 patients were randomized. Of these, 1159 (open n = 583; closed n = 576) were finally analyzed. The rate of pneumothorax or haemothorax was significantly reduced with the open strategy [odds ratio 0.27, 95% confidence interval (CI) 0.09-0.88; P = 0.029]. Operation time was shorter for the closed strategy. Primary success rates, tolerability, morbidity, dose rate of radiation, and 30-day mortality did not differ significantly between the groups. CONCLUSION: A primary open strategy by cut-down of the cephalic vein, if necessary enhanced by a modified Seldinger technique, reduces the frequency of pneumothorax or haemothorax after central venous port implantation significantly compared with a closed strategy by primary puncture of the subclavian vein without routine sonographic guidance. Therefore, open surgical cut-down should be the reference standard for port implantation in comparable cohorts. TRIAL REGISTRATION: German Clinical Trials Register DRKS 00004900.

Contamination After Disinfectant Rectal Washout in Left Colectomy as a Model for Transrectal NOTES: A Randomized Controlled Trial.

BACKGROUND: In natural orifice transluminal endoscopic surgery (NOTES) with transrectal (TR) access the intraoperative opening of the rectal wall poses a risk of intraperitoneal contamination and subsequent infectious complications. A rectal washout with a disinfectant may reduce this risk. The aim of the study was to assess the intraoperative contamination on the circular stapler pin when a rectal washout with povidone-iodine (RW-PI) or Ringer solution was performed in patients undergoing left-sided colectomy. Furthermore, the additional effect of an irrigation instrument on the contamination was evaluated. METHODS: In a patient and assessor blinded randomized controlled trial, patients undergoing left-sided colectomy were assigned to rectal washout with PI with an irrigation instrument (RW-PI; n = 23), rectal washout with Ringer solution with an irrigation instrument (RW-R; n = 21) or rectal washout with Ringer solution without an irrigation instrument (RW; n = 25). An end-to-end anastomosis with a circular stapler was performed. The contamination on the pin of the circular stapler was chosen as primary endpoint in order to simulate the intraabdominal contamination risk during TR NOTES. Secondary endpoints were contamination of the rectal mucosa, peritoneal contamination and postoperative morbidity. RESULTS: The contamination rate of the pin of the circular stapler did not differ (RW-PI 39.1%, RW-R 33.3%, RW 52.0%; P = 0.421), but contamination of the rectal mucosa was reduced (47.8% versus 95.2% versus 100%; P < 0.001) and peritoneal contamination tended to be reduced (39.1% versus 71.4% versus 60.0%; P = 0.09) when a rectal washout with PI was performed. The rates of infectious complications (17.4% versus 9.5% versus 12.0%; P = 0.821) and of overall complications (30.4% versus 28.6% versus 44.0%; P = 0.476) did not differ. CONCLUSIONS: Despite an intense rectal washout with PI, contamination of the stapler pin did not differ. Intraabdominal bacterial translocation was frequently encountered even after disinfectant rectal washout with PI. Further studies might focus on the clinical impact of intraabdominal contamination in TR NOTES.

Computer tomographic analysis of organ motion caused by respiration and intraoperative pneumoperitoneum in a porcine model for navigated minimally invasive esophagectomy.

BACKGROUND: Navigation systems have the potential to facilitate intraoperative orientation and recognition of anatomical structures. Intraoperative accuracy of navigation in thoracoabdominal surgery depends on soft tissue deformation. We evaluated esophageal motion caused by respiration and pneumoperitoneum in a porcine model for minimally invasive esophagectomy. METHODS: In ten pigs (20-34 kg) under general anesthesia, gastroscopic hemoclips were applied to the cervical (CE), high (T1), middle (T2), and lower thoracic (T3) level, and to the gastroesophageal junction (GEJ) of the esophagus. Furthermore, skin markers were applied. Three-dimensional (3D) and four-dimensional (4D) computed tomography (CT) scans were acquired before and after creation of pneumoperitoneum. Marker positions and lung volumes were analyzed with open source image segmentation software. RESULTS: Respiratory motion of the esophagus was higher at T3 (7.0 ± 3.3 mm, mean ± SD) and GEJ (6.9 ± 2.8 mm) than on T2 (4.5 ± 1.8 mm), T1 (3.1 ± 1.8 mm), and CE (1.3 ± 1.1 mm). There was significant motion correlation in between the esophageal levels. T1 motion correlated with all other esophagus levels (r = 0.51, p = 0.003). Esophageal motion correlated with ventilation volume (419 ± 148 ml) on T1 (r = 0.29), T2 (r = 0.44), T3 (r = 0.54), and GEJ (r = 0.58) but not on CE (r = - 0.04). Motion correlation of the esophagus with skin markers was moderate to high for T1, T2, T3, GEJ, but not evident for CE. Pneumoperitoneum led to considerable displacement of the esophagus (8.2 ± 3.4 mm) and had a level-specific influence on respiratory motion. CONCLUSIONS: The position and motion of the esophagus was considerably influenced by respiration and creation of pneumoperitoneum. Esophageal motion correlated with respiration and skin motion. Possible compensation mechanisms for soft tissue deformation were successfully identified. The porcine model is similar to humans for respiratory esophageal motion and can thus help to develop navigation systems with compensation for soft tissue deformation.

Evaluation of the LigaSure(™) Vessel Sealing System for bowel transection and intestinal anastomosis-an experimental study in a porcine model.

BACKGROUND: The purpose of the present study is to assess the value of the LigaSure™ Vessel Sealing System (LVSS) as a means for bowel transection and intestinal anastomosis. METHODS: We compared the LVSS for (1) transecting bowel and (2) creation of an intestinal anastomosis with standard methods such as stapler (S) and hand-sewn (HS) in a porcine model. For each study arm, i.e., bowel transection and anastomosis creation, both the small bowel and colon were examined. In total, ten transections and ten anastomoses were performed for each. Burst and anastomotic leak pressures were compared. RESULTS: In the study arm 1, LVSS achieved lowest burst pressures in both small bowel (LVSS 39.8 ± 3.6 mmHg, S 81.9 ± 3.9, HS 111.9 ± 14.7 mmHg, p < 0.0001) and colon transections (LVSS 21.5 ± 2.6 mmHg, S 79.5 ± 4.9, HS 91.0 ± 5.2 mmHg, p < 0.0001). There was no difference in burst pressures between S and HS in both small bowel and colon transections. In the study arm 2, LVSS showed the lowest anastomotic leak pressures for small bowel (LVSS 26.4 ± 2.6 mmHg, S 52.1 ± 6.2, HS 87.4 ± 7.0 mmHg, p < 0.0001) and colonic anastomoses (LVSS 16.9 ± 1.3 mmHg, S 55.9 ± 4.3, HS 74.4 ± 4.4 mmHg, p < 0.0001). Furthermore, small bowel and colonic anastomoses using S demonstrated significantly lower leak pressures than HS anastomosis p < 0.001 and p = 0.004, respectively. CONCLUSIONS: The LVSS achieves significantly lower burst pressures and anastomotic leak pressures for bowel transection and intestinal anastomosis than S and HS techniques. However, due to the achieved pressure levels of 39.8 ± 3.6 mmHg, LVSS appears to be a sufficient stand-alone method for bowel transection. Whether it can be used to perform intestinal anastomosis warrants further research in a survival model.

Radical surgery with total mesorectal excision in patients with T1 rectal cancer.

BACKGROUND: Radical resection with total mesorectal excision (TME) is the accepted standard of care for most rectal cancers. However, T1 rectal cancers may be at low risk for metastases and are therefore treatable with local resection. The aim of our study was to investigate whether the identification of these patients is possible through existing selection criteria. METHODS: Between 2001 and 2012, radical resection with TME was performed in 68 patients with a histologically confirmed T1 adenocarcinoma of the rectum. Each patient was staged preoperatively as lymph node negative. Patients at low risk to metastasize were defined as proposed by Hermanek and Gall (Int J Colorectal Dis 1(2):79-84, 1986), Kikuchi et al. (Dis Colon Rectum 38(12):1286-1295, 1995) and Hase et al. (Dis Colon Rectum 38(1):19-26, 1995) Postoperative morbidity, mortality, and oncological outcome were analyzed. RESULTS: Despite nodal negative staging, 9 of 68 patients (13 %) were node positive. Following the proposal of Hermanek and Gall, Kikuchi et al., and Hase et al., 14 % (5/37), 12 % (3/26), and 16 % (6/38) of patients, respectively, with low-risk tumors had lymph node metastases. In the univariate analysis, none of the investigated parameters could predict lymph node metastases. Following radical resection, none of the patients, regardless of nodal involvement, developed a recurrence. CONCLUSIONS: Preoperative diagnostics regarding lymphatic tumor propagation and histomorphological assessment of tumor samples as predictors of lymph node metastasis are unreliable. Following radical resection with TME, the oncological outcome of node-positive patients with T1 rectal adenocarcinoma is comparable with that of lymph node-negative patients. Considering the lymph node metastases rate, a local excision should always be complemented with additional therapy.

Influence of weight and structure on biological behavior of polypropylene mesh prostheses placed at the esophageal hiatus.

BACKGROUND: Experimental knowledge about mesh behavior at the esophageal hiatus is rare, but such information is essential in order to find a safe and effective method of mesh reinforcement. This study aimed to investigate the influence of mesh structure on the biological behavior of polypropylene prostheses placed at the hiatus. MATERIALS AND METHODS: Twenty-four pigs in three groups of eight underwent implantation of heavyweight small-porous (HW-SP), heavyweight large-porous (HW-LP), or lightweight large-porous (LW-LP) circular polypropylene mesh at the hiatus. Eight weeks later, the meshes were explanted. Macroscopic analysis was performed evaluating mesh deformation, adhesions, and position relative to the hiatal margin. Histological analysis comprised evaluation of foreign body reaction and tissue integration by mononuclear cell count and immunostaining of Ki-67, collagen type I, and collagen type III. RESULTS: No mesh-related complications occurred. Mesh shrinkage was observed within all groups and was the lowest for HW-LP, higher for HW-SP, and highest for LW-LP (13.8% versus 19.5% versus 25.5%; P<.001). The adhesion score was highest for HW-SP, lower for HW-LP, and lowest for LW-LP (11.0 versus 8.0 versus 6.0; P<.001). The collagen type I/III ratio was higher for HW-SP compared with HW-LP and LW-LP (3.1 versus 2.2 versus 1.8; P=.014). CONCLUSIONS: Heavyweight polypropylene meshes may be advantageous for application at the hiatus. They provide a solid fixation of the esophagogastric junction by adhesions, which may contribute to a reduction of hernia recurrence. In heavyweight meshes, the large-porous structure is associated with superior form stability, and small-porous meshes are superior with regard to solidity of tissue integration, which may prevent mesh migration.

One or two trainees per workplace in a structured multimodality training curriculum for laparoscopic surgery? Study protocol for a randomized controlled trial - DRKS00004675.

BACKGROUND: Laparoscopy training courses have been established in many centers worldwide to ensure adequate skill learning before performing operations on patients. Different training modalities and their combinations have been compared regarding training effects. Multimodality training combines different approaches for optimal training outcome. However, no standards currently exist for the number of trainees assigned per workplace. METHODS: This is a monocentric, open, three-arm randomized controlled trial. The participants are laparoscopically-naive medical students from Heidelberg University. After a standardized introduction to laparoscopic cholecystectomy (LC) with online learning modules, the participants perform a baseline test for basic skills and LC performance on a virtual reality (VR) trainer. A total of 100 students will be randomized into three study arms, in a 2:2:1 ratio. The intervention groups participate individually (Group 1) or in pairs (Group 2) in a standardized and structured multimodality training curriculum. Basic skills are trained on the box and VR trainers. Procedural skills and LC modules are trained on the VR trainer. The control group (Group C) does not receive training between tests. A post-test is performed to reassess basic skills and LC performance on the VR trainer. The performance of a cadaveric porcine LC is then measured as the primary outcome using standardized and validated ratings by blinded experts with the Objective Structured Assessment of Technical Skills. The Global Operative Assessment of Laparoscopic Surgical skills score and the time taken for completion are used as secondary outcome measures as well as the improvement of skills and VR LC performance between baseline and post-test. Cognitive tests and questionnaires are used to identify individual factors that might exert influence on training outcome. DISCUSSION: This study aims to assess whether workplaces in laparoscopy training courses for beginners should be used by one trainee or two trainees simultaneously, by measuring the impact on operative performance and learning curves. Possible factors of influence, such as the role of observing the training partner, exchange of thoughts, active reflection, model learning, motivation, pauses, and sympathy will be explored in the data analysis. This study will help optimize the efficiency of laparoscopy training courses. TRIAL REGISTRATION NUMBER: DRKS00004675.

Laparoscopic mesh-augmented hiatoplasty without fundoplication as a method to treat large hiatal hernias.

PURPOSE: Laparoscopic hiatal hernia repair with additional fundoplication is a commonly recommended standard surgical treatment for symptomatic large hiatal hernias with paraesophageal involvement (PEH). However, due to the risk of persistent side effects, this method remains controversial. Laparoscopic mesh-augmented hiatoplasty without fundoplication (LMAH), which combines hiatal repair and mesh reinforcement, might therefore be an alternative. METHODS: In this retrospective study of 55 (25 male, 30 female) consecutive PEH patients, the perioperative course and symptomatic outcomes were analyzed after a mean follow-up of 72 months. RESULTS: The mean DeMeester symptom score decreased from 5.1 to 1.8 (P < 0.001) and the gas bloating value decreased from 1.2 to 0.5 (P = 0.001). The dysphagia value was 0.7 before surgery and 0.6 (P = 0.379) after surgery. The majority of the patients were able to belch and vomit (96 and 92 %, respectively). Acid-suppressive therapy on a regular basis was discontinued in 68 % of patients. In 4 % of patients, reoperation was necessary due to recurrent or persistent reflux. A mesh-related stenosis that required endoscopic dilatation occurred in 2 % of patients. CONCLUSIONS: LMAH is feasible, safe and provides an anti-reflux effect, even without fundoplication. As operation-related side effects seem to be rare, LMAH is a potential treatment option for large hiatal hernias with paraesophageal involvement.

Navigation system for minimally invasive esophagectomy: experimental study in a porcine model.

BACKGROUND: Navigation systems potentially facilitate minimally invasive esophagectomy and improve patient outcome by improving intraoperative orientation, position estimation of instruments, and identification of lymph nodes and resection margins. The authors' self-developed navigation system is highly accurate in static environments. This study aimed to test the overall accuracy of the navigation system in a realistic operating room scenario and to identify the different sources of error altering accuracy. METHODS: To simulate a realistic environment, a porcine model (n = 5) was used with endoscopic clips in the esophagus as navigation targets. Computed tomography imaging was followed by image segmentation and target definition with the medical imaging interaction toolkit software. Optical tracking was used for registration and localization of animals and navigation instruments. Intraoperatively, the instrument was displayed relative to segmented organs in real time. The target registration error (TRE) of the navigation system was defined as the distance between the target and the navigation instrument tip. The TRE was measured on skin targets with the animal in the 0° supine and 25° anti-Trendelenburg position and on the esophagus during laparoscopic transhiatal preparation. RESULTS: On skin targets, the TRE was significantly higher in the 25° position, at 14.6 ± 2.7 mm, compared with the 0° position, at 3.2 ± 1.3 mm. The TRE on the esophagus was 11.2 ± 2.4 mm. The main source of error was soft tissue deformation caused by intraoperative positioning, pneumoperitoneum, surgical manipulation, and tissue dissection. CONCLUSION: The navigation system obtained acceptable accuracy with a minimally invasive transhiatal approach to the esophagus in a realistic experimental model. Thus the system has the potential to improve intraoperative orientation, identification of lymph nodes and adequate resection margins, and visualization of risk structures. Compensation methods for soft tissue deformation may lead to an even more accurate navigation system in the future.

Multimodal visibility (radiography, computed tomography, and magnetic resonance imaging) of microspheres for transarterial embolization tested in porcine kidneys.

OBJECTIVE: The objective of this study was to test multimodal visibility (radiography, computed tomography [CT], and magnetic resonance imaging [MRI]) of microspheres for transarterial embolization in porcine kidneys. MATERIALS AND METHODS: Currently available embolization particles (microspheres) were modified. A dense x-ray material (barium sulfate) was added to create visibility for radiography and CT. A magnetic substance (iron oxide) was additionally added to create visibility for MRI. This chemical modification was performed for particles with sizes of 100 ± 25 and 700 ± 50 µm. Three different prototypes per size class (samples A, B, and C) resulted, each with a different degree of barium sulfate but with the same degree of iron oxide. The currently available embolization particles with sizes of 100 ± 25 and 700 ± 50 µm were used as controls (sample control). Eight renal arteries of 4 pigs were embolized. Study end points were size distribution evaluated in vitro as well as qualitative and quantitative particle visibility evaluated in vivo. RESULTS: The size distribution of the particles with a size of 100 ± 25 µm was between 96 ± 11 µm for sample A and 102 ± 13 µm for the sample control without significant differences (n.s.). The size distribution of the particles with a size of 700 ± 50 µm was between 691 ± 20 µm for sample A and 716 ± 34 µm for sample C without significant differences (n.s.). For radiography, the particles with sizes of 100 ± 25 and 700 ± 50 µm for samples A, B, and C were definitely visible during the embolization. The sample control was definitely not visible. For CT and MRI (T1-weighted [T1w] and T2-weighted [T2w]), the particles with sizes of 100 ± 25 and 700 ± 50 µm for samples A, B, and C were definitely visible after the embolization. The sample control was definitely not visible. For CT, the signal-to-noise ratio for samples A, B, and C increased significantly after the embolization (eg, sample A, particles with a size of 100 ± 25 µm: 66.5% ± 23.7%, P < 0.05). The signal-to-noise ratio for the sample control did not change after the embolization (eg, sample control, particles with a size of 700 ± 25 µm: -0.2% ± 15.2%, n.s.). For MRI (T1w and T2w), the signal-to-noise ratio for samples A, B, and C decreased significantly after the embolization (eg, sample B, particles with a size of 700 ± 50 µm, T1w: -72.9% ± 6.6%; P < 0.05). The signal-to-noise ratio for the sample control did not change after the embolization (eg, sample control, particles with a size of 100 ± 25 µm, T2w: 6.2% ± 16.1%, n.s.). CONCLUSIONS: In this study, the chemical modification of the currently available microspheres for transarterial embolization resulted in a size distribution comparable with the currently available microspheres and created multimodal visibility for radiography, CT, and MRI.

Virtual reality does not meet expectations in a pilot study on multimodal laparoscopic surgery training.

BACKGROUND: The purpose of the present study was to determine the value of virtual reality (VR) training for a multimodality training program of basic laparoscopic surgery. MATERIALS AND METHODS: Participants in a two-day multimodality training for laparoscopic surgery used box trainers, live animal training, and cadaveric training on the pulsating organ perfusion (POP) trainer in a structured and standardized training program. The participants were divided into two groups. The VR group (n = 13) also practiced with VR training during the program, whereas the control group (n = 14) did not use VR training. The training modalities were assessed using questionnaires with a five-point Likert scale after the program. Concerning VR training, members of the control group assessed their expectations, whereas the VR group assessed the actual experience of using it. Skills performance was evaluated with five standardized test tasks in a live porcine model before (pre-test) and after (post-test) the training program. Laparoscopic skills were measured by task completion time and a general performance score for each task. Baseline tests were compared with laparoscopic experience of all participants for construct validity of the skills test. RESULTS: The expected benefit from VR training of the control group was higher than the experienced benefit of the VR group. Box and POP training received better ratings from the VR group than from the control group for some purposes. Both groups improved their skill parameters significantly from pre-training to post-training tests [score +17 % (P < 0.01), time -29 % (P < 0.01)]. No significant difference was found between the two groups for laparoscopic skills improvement except for the score in the instrument coordination task. Construct validity of the skills test was significant for both time and score. CONCLUSIONS: At its current level of performance, VR training does not meet expectations. No additional benefit was observed from VR training in our multimodality training program.

Robotic-assisted paraesophageal hernia repair--a case-control study.

AIMS: The da Vinci® telemanipulation system offers a wide range of precise movements and 3D visualization with depth perception and magnification effect. Such a system could be useful for improving minimally invasive procedures-as in the case of large hiatal hernia with paraesophageal involvement (PEH) repair. Studies reporting on the robotic-assisted PEH repair are scarce, and a comparison to the standard operation techniques is lacking. Therefore, we decided to investigate the feasibility and safety of robotic-assisted surgery (RAS) compared to conventional laparoscopic (CLS) and open surgery (OS) for the first time. METHODS: We investigated 42 patients for the perioperative outcome after PEH repair. Twelve patients were operated on with RAS, 17 with CLS, and 13 with OS. Operating time, intraoperative blood loss, intra- and postoperative complications, mortality, and duration of hospital stay were analyzed in each method. RESULTS: On average, operating time in the RAS group was 38 min longer, and the intraoperative blood was loss 217 ml lower compared to OS. Both results were similar to the CLS group. The intraoperative complication rate was similar in all groups. The postoperative complication rate in the RAS group was significantly lower than the OS group, though again similar to the CLS group. The hospital stay was 5 days shorter in the RAS group than the OS group and once again similar to the CLS group. CONCLUSION: The results show that RAS is feasible and safe. It appears to be an alternative to OS due to lower intraoperative blood loss and potentially fewer postoperative complications, as well as shorter hospital stay. Though, RAS is not superior to CLS.

Multimodal visibility of a modified polyzene-F-coated spherical embolic agent for liver embolization: feasibility study in a porcine model.

PURPOSE: To evaluate multimodal visibility of modified currently available microspheres on radiography, magnetic resonance (MR) imaging, and computed tomography (CT) in a porcine liver model. MATERIALS AND METHODS: Livers of four pigs were embolized with two sizes (100 µm ± 25 and 700 µm ± 50) of modified Embozene Microspheres embedded with different densities of barium sulfate and iodine as radiopaque materials (intensity groups A-C, with increasing intensity from A to C for 100 µm and intensities A and C for 700 µm) and iron oxide as magnetic substance for MR imaging visibility. Pigs embolized with currently available Embozene Microspheres served as control groups. Pre- and postinterventional MR imaging (T1- and T2-weighted) and CT were performed. Qualitative and quantitative (ie, determination of signal-to-noise ratio [SNR]) particle visibility was evaluated on radiography, MR imaging, and CT. RESULTS: Modified particles of both sizes were visible on radiography, MR imaging, and CT. Particles in the control group were not visible. For modified particles of both sizes, SNRs measured on MR imaging decreased significantly after embolization (eg, cluster analysis of group A, 100 µm ± 50 particles, T1-weighted, -74.6% ± 3.4; P = .03). For modified particles of both sizes, SNR measured on CT increased significantly after embolization (eg, cluster analysis of group A, 700 µm ± 25 particles, +54.3% ± 13.5; P = .03). CONCLUSIONS: Modification of currently available Embozene Microspheres was successful, with multimodal visibility on radiography, MR imaging, and CT in porcine liver. In the future, this might improve procedure accuracy and allow monitoring, control, and improvement of embolotherapy during and after the procedure.

Challenges and pitfalls of experimental bariatric procedures in rats.

INTRODUCTION: The impact of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on obesity and obesity-related diseases is unquestionable. Up to now, the technical descriptions of these techniques in animals/rats have not been very comprehensive. METHODS: For SG and RYGB, operating time, learning curve, and intraoperative mortality in relation to weight of the rat and type of anesthesia were recorded. Furthermore, a review of the literature on experimental approaches towards SG and RYGB in rats was carried out, merging in a detailed technical description for both procedures. RESULTS: The data presented here revealed that the mean operating time for SG (69.4 ± 22.2 min (SD)) was shorter than for RYGB (123.0 ± 20.7 min). There is a learning curve for both procedures, resulting in a reduced operating time of up to 60% in SG and 35% in RYGB (p < 0.05; t-test). However, with increased weight, operating time increases to about 80 min for SG and about 120 min for RYGB. Obese rats have an increased intraoperative mortality rate of up to 50%. After gaseous anesthesia the mortality can be even higher. The literature search revealed 40 papers dealing with SG and RYGB in rats. 18 articles (45%) contained neither photographs nor illustrations; 14 articles (35%) did not mention the applied type of anesthesia. The mortality rate was described in 15 papers (37.5%). CONCLUSION: Experimental obesity surgery in rats is challenging. Because of the high mortality in obese rats operated under gaseous anesthesia, exercises to establish the techniques should be performed in small rats using intraperitoneal anesthesia.

Excessive weight loss after sleeve gastrectomy: a systematic review.

BACKGROUND: The clinical significance of sleeve gastrectomy (SG) as a primary bariatric intervention is still under debate. This article aims to systematically analyze excessive weight loss (EWL) in patients after SG. METHODS: A systematic literature search on SG from the period January 2003 to December 2010 was performed. Data described from systematic reviews dealing with gastric bypass procedures was used as comparator. RESULTS: The final study included 123 papers describing 12,129 patients. Most of the papers describe EWL at 12 months (43.9% of all papers). For SG, the maximum EWL occurred 24 and 36 months postoperatively with a mean EWL of 64.3% (minimum 46.1%, maximum 75.0%) and 66.0% (minimum 60.0%, maximum 77.5%), respectively. At 12 months, the mean EWL in patients receiving SG was significantly lower when compared to patients who underwent gastric bypass (SG 56.1%, gastric bypass 68.3%; p < 0.01, two-sided Wilcoxon test). Although patients with gastric bypass still had higher EWL rates at 24 months compared to patients after SG, these differences were not significant (SG 61.3%, gastric bypass 69.6%; p = 0.09, two-sided Wilcoxon rank-sum test). Reoperations after SG are necessary in 6.8% (range 0.7-25%) of cases with patients receiving SG as a stand alone procedure and in 9.6-28.5% of cases with patients undergoing SG as a planned first stage procedure. CONCLUSIONS: SG is an effective bariatric procedure with a lasting effect on EWL. Compared with gastric bypasses, there is no difference in EWL at the time point of 24 months.

Effect of tissue perfusion on microwave ablation: experimental in vivo study in porcine kidneys.

PURPOSE: To determine the effect of tissue perfusion on microwave ablation lesions in an experimental in vivo study in porcine kidneys. MATERIALS AND METHODS: Twelve kidneys of six pigs were studied. In each animal, two microwave ablations were created in one kidney without limitation of tissue perfusion (group 1). In the other kidney, two microwave ablations were performed with interruption of blood flow (group 2). All microwave ablations were performed with identical system parameters (eg, temperature control mode, ablation time of 80 s, and temperature of 110°C). The animals were euthanized 3 hours later. The kidneys were harvested and cut into 2-3-mm transverse slices. Microwave ablation zone dimensions (eg, length, width, and volume) and shape (eg, sphericity ratio) and corresponding variability were compared between groups. RESULTS: Microwave ablation areas were significantly longer (41.6 mm ± 4.0 vs 34.2 mm ± 5.9; P < .01) and wider (16.6 mm ± 1.2 vs 12.2 mm ± 2.1; P < .001) in group 2 than in group 1. Similarly, microwave ablation volume was significantly greater in group 2 compared with group 1 (6.7 cm(3) ± 1.0 vs 3.3 cm(3) ± 1.2; P < .001). Ablation area shapes were similar between groups (sphericity ratio, 2.57 ± 0.42 vs 2.39 ± 0.34). Ablation area variabilities were also comparable between groups (volume variance of 1.32 vs 0.93; sphericity ratio variance of 0.18 vs 0.11). CONCLUSIONS: After interruption of blood flow, microwave ablation areas are significantly larger than those achieved without limitation of tissue perfusion. Microwave ablation area shape and variability were comparable between study groups.