Influence of open-source virtual-reality based gaze training on navigation performance in Retinitis pigmentosa patients in a crossover randomized controlled trial.

METHODS: A group of RP patients (n = 8, aged 20-60) participated in a study consisting of two 4-week-phases, both carried out by the same patient group in randomized order: In the 'training phase', participants carried out a Virtual-Reality gaze training for 30 minutes per day; In the 'control phase', no training occurred. Before and after each phase, participants were tasked to move through a randomized real-world obstacle course. Navigation performance in the obstacle course as well as eye-tracking data during the trials were evaluated. The study is registered at the German Clinical Trials Register (DRKS) with the ID DRKS00032628. RESULTS: On average, the time required to move through the obstacle course decreased by 17.0% after the training phase, the number of collisions decreased by 50.0%. Both effects are significantly higher than those found in the control phase (p < 0.001 for required time, p = 0.0165 for number of collisions), with the required time decreasing by 5.9% and number of collisions decreasing by 10.4% after the control phase. The average visual area observed by participants increases by 4.41% after training, however the effect is not found to be significantly higher than in the control phase (p = 0.394). CONCLUSION: The performance increase over the training phase significantly surpasses the natural learning effect found in the control phase, suggesting that Virtual-Reality based gaze training can have a positive effect on real-world navigation tasks for patients with RP. The training is available as work-in-progress open-source software.

Optical Emission Spectroscopy for the Real-Time Identification of Malignant Breast Tissue.

Breast conserving resection with free margins is the gold standard treatment for early breast cancer recommended by guidelines worldwide. Therefore, reliable discrimination between normal and malignant tissue at the resection margins is essential. In this study, normal and abnormal tissue samples from breast cancer patients were characterized ex vivo by optical emission spectroscopy (OES) based on ionized atoms and molecules generated during electrosurgical treatment. The aim of the study was to determine spectroscopic features which are typical for healthy and neoplastic breast tissue allowing for future real-time tissue differentiation and margin assessment during breast cancer surgery. A total of 972 spectra generated by electrosurgical sparking on normal and abnormal tissue were used for support vector classifier (SVC) training. Specific spectroscopic features were selected for the classification of tissues in the included breast cancer patients. The average classification accuracy for all patients was 96.9%. Normal and abnormal breast tissue could be differentiated with a mean sensitivity of 94.8%, a specificity of 99.0%, a positive predictive value (PPV) of 99.1% and a negative predictive value (NPV) of 96.1%. For 66.6% patients all classifications reached 100%. Based on this convincing data, a future clinical application of OES-based tissue differentiation in breast cancer surgery seems to be feasible.

[Methods, applications, and future perspectives of intraoperative tissue identification]. / Methoden, Anwendungen und Zukunftsperspektiven der intraoperativen Gewebeerkennung.

Over the last century, there has been a steady development of new technologies for intraoperative tissue identification and differentiation. The applications are varied, with the core purpose being to identify target structures while preserving adjacent tissue and thereby follow a general paradigm of minimally invasive medicine. Particularly in oncology, a further asset of these technologies is the identification or classification of neoplastic tissue to support and improve therapy, for example, in breast cancer surgery.Many technologies under consideration make use of the different physical characteristics of treated tissues, such as induced fluorescence, optical coherence, and electrical impedance.Recent developments are focusing on moving from ex vivo to in situ and from asynchronous to real-time assistance of the clinicians, for example, by means of optical emission spectroscopy. Refinements of existing and the creation of new methods will include AI tools to make them more powerful while reducing the inter-operator variability in operative interventions. This talk addresses several aspects of the usage and suitability of these technologies for intraoperative, therapy-supporting application.

Hybrid argon plasma coagulation (HybridAPC) versus sharp excision for the treatment of endometriosis: a prospective randomized clinical trial.

PURPOSE: Endometriosis is a benign, but potentially serious gynaecological condition in terms of abdominal pain and impaired fertility. Laparoscopic excision techniques are considered the therapeutic standard. HybridAPC is presented as a novel technique for the non-contact thermal ablation of peritoneal endometriosis with simultaneous protection of the underlying thermosensitive structures by creating a needle-free elevated fluid cushion which enables a safer exposure and distance, as well as potentially improved peritoneal conditioning prior to APC. METHODS: In this prospective randomized clinical trial, 39 patients with 132 superficial endometriotic lesions in total were treated with HybridAPC or sharp excision in an initial laparoscopic procedure according to randomization. In a second-look laparoscopy, adhesion formation was rated macroscopically. Histologic samples were taken from previously treated areas for evaluation of eradication rate. RESULTS: The eradication rate was not significantly different between HybridAPC treatment and sharp excision (65 vs. 81%, p = .55). Adhesions formed in 5% of HybridAPC-treated lesions and in 10% after sharp excision (p = .49). HybridAPC treatment was significantly faster than sharp excision (69 vs. 106 s, p < .05). No intra- and postoperative complications were registered. CONCLUSION: This clinical trial demonstrates the feasibility of this novel surgical technique with a promising impact on adhesion prevention. Compared to sharp excision, HybridAPC is likely to be a safe, tissue-preserving, and fast method for the treatment of peritoneal endometriosis.

The Unfolding Space Glove: A Wearable Spatio-Visual to Haptic Sensory Substitution Device for Blind People.

This paper documents the design, implementation and evaluation of the Unfolding Space Glove-an open source sensory substitution device. It transmits the relative position and distance of nearby objects as vibratory stimuli to the back of the hand and thus enables blind people to haptically explore the depth of their surrounding space, assisting with navigation tasks such as object recognition and wayfinding. The prototype requires no external hardware, is highly portable, operates in all lighting conditions, and provides continuous and immediate feedback-all while being visually unobtrusive. Both blind (n = 8) and blindfolded sighted participants (n = 6) completed structured training and obstacle courses with both the prototype and a white long cane to allow performance comparisons to be drawn between them. The subjects quickly learned how to use the glove and successfully completed all of the trials, though still being slower with it than with the cane. Qualitative interviews revealed a high level of usability and user experience. Overall, the results indicate the general processability of spatial information through sensory substitution using haptic, vibrotactile interfaces. Further research would be required to evaluate the prototype's capabilities after extensive training and to derive a fully functional navigation aid from its features.

Fluid cushion protects against thermal damage during argon plasma coagulation.

BACKGROUND: Thermal damage to the muscle layer during mucosal application of argon plasma coagulation (APC) may be avoided by creating a fluid cushion within the submucosal layer, but the minimum injection volume needed or the ideal injection fluid are yet to be established. We conducted a systematic ex vivo study with this aim. METHODS: All experiments were performed in an ex vivo porcine gastrointestinal tract model. Five different fluids (saline, Glyceol, Gelafundin, Voluven, and Eleview) of different volumes were injected into the submucosa of different parts of the gastrointestinal tract. APC was applied to the mucosa at different power settings. Immediately after APC treatment, the temperature was measured through a thermocouple placed inside the fluid cushion, just on top of the muscle layer. The minimum volume of fluid needed to protect the muscle layer from thermal damage was determined. RESULTS: There was no difference in the temperature measured among the different injection fluids at the surface of the muscle, in all the locations, at equal injection volumes and power settings. The minimum amounts of fluid needed to protect the muscle layer were 2 and 3 mL for power settings of 30-90 W and 90-120 W, respectively. CONCLUSIONS: Normal saline and 4 commercially available submucosal injection fluids possess similar thermal protective effects. To reduce the likelihood of thermal damage to deeper layers when APC is applied, a minimum injection volume of 3 mL is recommended if less than 90 W power will be utilized over 3 sec.

Influence of Systematic Gaze Patterns in Navigation and Search Tasks with Simulated Retinitis Pigmentosa.

People living with a degenerative retinal disease such as retinitis pigmentosa are oftentimes faced with difficulties navigating in crowded places and avoiding obstacles due to their severely limited field of view. The study aimed to assess the potential of different patterns of eye movement (scanning patterns) to (i) increase the effective area of perception of participants with simulated retinitis pigmentosa scotoma and (ii) maintain or improve performance in visual tasks. Using a virtual reality headset with eye tracking, we simulated tunnel vision of 20° in diameter in visually healthy participants (n = 9). Employing this setup, we investigated how different scanning patterns influence the dynamic field of view-the average area over time covered by the field of view-of the participants in an obstacle avoidance task and in a search task. One of the two tested scanning patterns showed a significant improvement in both dynamic field of view (navigation 11%, search 7%) and collision avoidance (33%) when compared to trials without the suggested scanning pattern. However, participants took significantly longer (31%) to finish the navigation task when applying this scanning pattern. No significant improvements in search task performance were found when applying scanning patterns.

Navigation aid for blind persons by visual-to-auditory sensory substitution: A pilot study.

PURPOSE: In this study, we investigate to what degree augmented reality technology can be used to create and evaluate a visual-to-auditory sensory substitution device to improve the performance of blind persons in navigation and recognition tasks. METHODS: A sensory substitution algorithm that translates 3D visual information into audio feedback was designed. This algorithm was integrated in an augmented reality based mobile phone application. Using the mobile device as sensory substitution device, a study with blind participants (n = 7) was performed. The participants navigated through pseudo-randomized obstacle courses using either the sensory substitution device, a white cane or a combination of both. In a second task, virtual 3D objects and structures had to be identified by the participants using the same sensory substitution device. RESULTS: The realized application for mobile devices enabled participants to complete the navigation and object recognition tasks in an experimental environment already within the first trials without previous training. This demonstrates the general feasibility and low entry barrier of the designed sensory substitution algorithm. In direct comparison to the white cane, within the study duration of ten hours the sensory substitution device did not offer a statistically significant improvement in navigation.

A prospective randomized experimental study to investigate the peritoneal adhesion formation after waterjet injection and argon plasma coagulation (HybridAPC) in a rat model.

BACKGROUND: This prospective, randomized, controlled, single-blinded study investigates the peritoneal adhesion formation of HybridAPC (waterjet elevation of the peritoneum with subsequent argon plasma coagulation) versus only waterjet (elevation with the same instrument, but without subsequent argon plasma coagulation) in a rat model (24 female Wistar rats). MATERIALS AND METHODS: Bilateral lesions were created on the abdominal wall with HybridAPC on one sidewall and waterjet elevation on the other sidewall of the peritoneum in a standard fashion. After 10 days, the rats were euthanized to evaluate the peritoneal trauma sites. MAIN OUTCOME MEASURE(S): Adhesion incidence, quantity, and quality were scored 10 days postoperatively and studied histopathologically. RESULT(S): Incidence of adhesion formation was 2.3% for HybridAPC; no adhesions occurred for peritoneal elevation with saline (p = 1.00). Histologic evaluation revealed no acute inflammation in both groups. An overall moderate degree of granulation tissue formation and myonecrosis was observed in the HybridAPC group, whereas no chronic inflammation and myonecrosis occurred after elevation without thermal ablation (p < 0.0001). CONCLUSION(S): This study investigates the effect of waterjet elevation of the peritoneum with and without subsequent thermal ablation on adhesion formation in a rat model for the first time. Peritoneal waterjet elevation with saline does not provide any risk of adhesion formation. Thermal coagulation with APC after waterjet elevation of the peritoneum creates advantageous peritoneal conditions due to a permanent moist tissue surface and the cooling effect of the injected solution, resulting in no significant difference in adhesion formation compared to peritoneal elevation without thermal ablation. HybridAPC can thus be regarded as a beneficial coagulation method with only minor adhesion formation due to positive tissue effects of the combined waterjet.

A randomised trial of endoscopic submucosal dissection versus endoscopic mucosal resection for early Barrett's neoplasia.

BACKGROUND: For endoscopic resection of early GI neoplasia, endoscopic submucosal dissection (ESD) achieves higher rates of complete resection (R0) than endoscopic mucosal resection (EMR). However, ESD is technically more difficult and evidence from randomised trial is missing. OBJECTIVE: We compared the efficacy and safety of ESD and EMR in patients with neoplastic Barrett's oesophagus (BO). DESIGN: BO patients with a focal lesion of high-grade intraepithelial neoplasia (HGIN) or early adenocarcinoma (EAC) ≤3 cm were randomised to either ESD or EMR. Primary outcome was R0 resection; secondary outcomes were complete remission from neoplasia, recurrences and adverse events (AEs). RESULTS: There were no significant differences in patient and lesion characteristics between the groups randomised to ESD (n=20) or EMR (n=20). Histology of the resected specimen showed HGIN or EAC in all but six cases. Although R0 resection defined as margins free of HGIN/EAC was achieved more frequently with ESD (10/17 vs 2/17, p=0.01), there was no difference in complete remission from neoplasia at 3 months (ESD 15/16 vs EMR 16/17, p=1.0). During a mean follow-up period of 23.1±6.4 months, recurrent EAC was observed in one case in the ESD group. Elective surgery was performed in four and three cases after ESD and EMR, respectively (p=1.0). Two severe AEs were recorded for ESD and none for EMR (p=0.49). CONCLUSIONS: In terms of need for surgery, neoplasia remission and recurrence, ESD and EMR are both highly effective for endoscopic resection of early BO neoplasia. ESD achieves a higher R0 resection rate, but for most BO patients this bears little clinical relevance. ESD is, however, more time consuming and may cause severe AE. TRIAL REGISTRATION NUMBER: NCT1871636.

In silico evaluation of geometry variations with respect to the thermal spread during coagulation of egg white using bipolar vessel sealing instruments.

BACKGROUND: Bipolar vessel sealing is an efficient electrosurgical procedure for the occlusion of blood vessels particularly during minimally invasive surgery. Reliable knowledge of the thermal spread is crucial for a safe application of bipolar vessel sealing instruments when operating close to thermo-sensitive structures, such as nerves. The evolution of the thermal spread over time and space depends on a variety of parameters, such as the biological tissue, the energy applied to the tissue, and the geometry of the vessel sealing instrument. Mathematical modeling has proven useful for the prediction of the thermal spread. It is, thus, a promising tool for the systematic analysis of the influence of geometrical changes on the thermal spread. RESULTS: We present an experimentally validated in silico study to evaluate the impact of geometry variations on the progression of chicken egg white coagulation and the final shape of coagulated egg white as an approximation of the temporal and spatial evolution of the thermal spread during bipolar vessel sealing. Egg white has similar thermal and electrical properties to human tissue, with the advantage being that the spatial and temporal evolution of the thermal spread can be visually gauged. The simulations were performed using a mathematical model based on the finite element analysis of chicken egg white. The progression of egg white coagulation was predicted for two different peak voltages and various electrode geometries. Starting with two planar electrodes, one electrode was gradually changed to adopt a wedge shape. These changes to the geometry showed a distinct influence on the progression of egg white coagulation in the simulations. The predictions were successfully validated using an experimental setup with two different electrodes representing the extreme geometries. DISCUSSION: The predicted spatial temperature distributions were experimentally validated for two geometries. Our simulation study shows that the geometry has a pronounced influence on the thermal spread and, thus, is a suitable parameter to reduce thermal damage. The in silico optimization of instrument designs is a suitable tool to accelerate the development of new vessel sealing instruments, with only a few promising designs having to be tested as prototypes.

A Prospective Randomized Experimental Study to Investigate the Eradication Rate of Endometriosis after Surgical Resection versus Aerosol Plasma Coagulation in a Rat Model.

PURPOSE: To investigate the eradication rate of endometriosis after surgical resection (SR) vs. thermal ablation with aerosol plasma coagulation (AePC) in a rat model. METHODS: In this prospective, randomized, controlled, single-blinded animal study endometriosis was induced on the abdominal wall of 34 female Wistar rats. After 14 days endometriosis was either removed by SR or ablated by AePC. 14 days later the rats were euthanized to evaluate the eradication rate histopathologically. Intervention times were recorded. RESULTS: Eradication rate of endometriosis after 14 days did not significantly differ between AePC and SR (p=0.22). Intervention time per endometrial lesion was 22.1 s for AePC and 51.8 s for SR (p<0.0001). CONCLUSIONS: This study compares the eradication rate of the new aerosol plasma coagulation device versus standard surgical resection of endometriosis in a rat model. Despite being a thermal method, AePC showed equality towards SR regarding eradication rate but with significantly shorter intervention time.

Real-time tissue differentiation based on optical emission spectroscopy for guided electrosurgical tumor resection.

Complete surgical removal of cancer tissue with effective preservation of healthy tissue is one of the most important challenges in modern oncology. We present a method for real-time, in situ differentiation of tissue based on optical emission spectroscopy (OES) performed during electrosurgery not requiring any biomarkers, additional light sources or other excitation processes. The analysis of the optical emission spectra, enables the differentiation of healthy and tumorous tissue. By using multi-class support vector machine (SVM) algorithms, distinguishing between tumor types also seems to be possible. Due to its fast reaction time (0.05s) the method can be used for real-time navigation helping the surgeon achieve complete resection. The system's easy realization has been proven by successful integration in a commercial electro surgical unit (ESU). In a first step the method was verified by using ex vivo tissue samples. The histological analysis confirmed, 95% of correctly classified tissue types.

The tissue effect of argon-plasma coagulation with prior submucosal injection (Hybrid-APC) versus standard APC: A randomized ex-vivo study.

BACKGROUND: Thermal ablation for Barrett's oesophagus has widely been established in gastrointestinal endoscopy during the last decade. The mainly used methods of radiofrequency ablation (RFA) and argon-plasma coagulation (APC) carry a relevant risk of stricture formation of up to 5-15%. Newer ablation techniques that are able to overcome this disadvantage would therefore be desirable. The aim of the present study was to compare the depth of tissue injury of the new method of Hybrid-APC versus standard APC within a randomized study in a porcine oesophagus model. METHODS: Using a total of eight explanted pig oesophagi, 48 oesophageal areas were ablated either by standard or Hybrid-APC (APC with prior submucosal fluid injection) using power settings of 50 and 70 W. The depth of tissue injury to the oesophageal wall was analysed macroscopically and histopathologically. RESULTS: Using 50 W, mean coagulation depth was 937 ± 469 µm during standard APC, and 477 ± 271 µm during Hybrid-APC (p = 0.064). Using 70 W, coagulation depth was 1096 ± 320 µm (standard APC) and 468 ± 136 µm (Hybrid-APC; p = 0.003). During all settings, damage to the muscularis mucosae was observed. Using standard APC, damage to the submucosal layer was observed in 4/6 (50 W) and 6/6 cases (70 W). During Hybrid-APC, coagulation of the submucosal layer occurred in 2/6 (50 W) and 1/6 cases (70 W). The proper muscle layer was only damaged during conventional APC (50 W: 1/6; 70 W: 3/6). LIMITATIONS: Ex-vivo animal study with limited number of cases. CONCLUSIONS: Hybrid-APC reduces coagulation depth by half in comparison with standard APC, with no thermal injury to the proper muscle layer. It may therefore lead to a lower rate of stricture formation during clinical application.

Randomized experimental study to investigate the peritoneal adhesion formation of conventional monopolar contact coagulation versus noncontact argon plasma coagulation in a rat model.

OBJECTIVE: To investigate peritoneal adhesion formation of monopolar contact coagulation (MCC) versus noncontact argon plasma coagulation (APC) in a rat model. DESIGN: Randomized, controlled, single-blinded animal study. SETTING: University laboratory. ANIMAL(S): Sixteen female Wistar rats. INTERVENTION(S): Bilateral lesions were created on the abdominal wall with MCC and APC in a standard fashion. After 10 days, the rats were euthanized to evaluate the peritoneal trauma sites. MAIN OUTCOME MEASURE(S): Adhesion incidence, quantity, and quality were scored 10 days postoperatively and studied histopathologically. RESULT(S): Average energy intake was 99.5 ± 7.39 J for APC and 95.7 ± 9.62 J for monopolar contact coagulation. Incidence of adhesion formation was 50.0% for noncontact APC and 85.4% for MCC. MCC induced significantly more vascular adhesions. Histological evaluation revealed no significant differences regarding average depth of lesions induced by APC and MCC. Both groups showed almost identical morphology of necrosis and granulation tissue formation. CONCLUSION(S): This study compares for the first time adhesion formation of MCC versus noncontact APC in a rat model. With a similar energy intake, contact coagulation induced a significantly higher rate of adhesion formation. APC-induced adhesions were significantly less vascularized compared with MCC adhesions. Besides the thermal effects of both coagulation methods, the direct mechanical contact of the MCC electrode with the highly sensitive peritoneum is thus determined to be a pivotal additional stimulus for adhesion formation.

Bipolar vessel sealing: instrument contamination and wear have little effect on seal quality and success in a porcine in vitro model.

PURPOSE: The aim of this study is to systematically investigate under standardized experimental conditions the effects of instrument contamination and wear on the quality of bipolar vessel sealing (BVS) achieved using a reusable instrument. METHODS: The study was designed as a prospective, randomized, and controlled in vitro study and conducted in an academic research environment. Reusable bipolar coagulation forceps (BiClamp® 200 C, ERBE Elektromedizin) were used to apply sealing pressures of 300-1,100 mN/mm(2) to 239 renal arteries from commercially slaughtered female pigs (Swabian-Hall Swine). Forceps jaws were coated with porcine blood, blood and collagen, or blood, collagen, and fat to simulate instrument contamination with biological material during surgery. Clinical wear was mimicked by sandpaper abrasion. The main outcome measures were seal success (resistance to 250 mmHg intraluminal pressure for 2 min) and seal stability (burst pressure). RESULTS: Sealing pressure had a significant impact, with 800 mN/mm(2) producing the best sealing results. Seal success increased with total energy applied to the tissue, a higher maximum temperature, and longer coagulation as indicated by desiccation time. Experimental contamination had no significant impact on seal success and only a limited effect on seal stability. Similarly, abrasive wear also had no significant effect on either seal quality or seal strength. CONCLUSIONS: The impact of bipolar forceps contamination and wear on seal success and quality was negligible in our in vitro model. To achieve high-quality seals, it is essential to use adequate sealing pressures. Our findings could have direct implications for the design and clinical handling of BVS instruments.

A Prospective Experimental Study to Investigate the Peritoneal Adhesion Formation of Argon Plasma Coagulation (APC) Versus a Novel Aerosol Plasma in a Rat Model.

BACKGROUND: This is a prospective, randomized, controlled, single-blinded study to investigate peritoneal adhesion formation of standard argon plasma coagulation (APC) versus aerosol plasma coagulation in a rat model. METHODS: Bilateral lesions were created on the abdominal wall of 16 female Wistar rats with standard and aerosol plasma coagulation APC energy in a standard fashion. After 10 days, the rats were killed humanely to evaluate the peritoneal trauma sites. Adhesion incidence, quantity, and quality were scored 10 days postoperatively and studied histopathologically. RESULTS: Average energy intake was 97.7 ± 3.1 J for APC and 93.8 ± 4.2 J for aerosol plasma coagulation. Incidence of adhesion formation was 74.2% for standard APC and 16.1% for aerosol plasma coagulation (P < .0001). Standard APC mainly results in dense adhesions. Histological evaluation revealed no significant difference with regard to the average depth of lesions created by APC and aerosol plasma coagulation (P = 0.21) at day 10; both groups showed an identical morphology of necrosis and granulation tissue formation. CONCLUSIONS: This study compares adhesion formation of standard APC versus aerosol plasma coagulation in a rat model. Standard APC produced significantly more adhesions. Aerosol plasma coagulation creates fewer adhesions, which are of lower grade, which seems to be achieved mainly by improved peritoneal conditioning in this animal model.

A prospective, randomized clinical comparison between UltraCision and the novel sealing and cutting device BiCision in patients with laparoscopic supracervical hysterectomy.

BACKGROUND: Various surgical procedures for hysterectomy exist; with laparoscopic supracervical hysterectomy (LASH) becoming an established option in recent years. Therefore, energy-based technologies for rapid tissue sealing and cutting are in the focus of surgeons. The aim of this trial was to prove or disprove investigated noninferiority of the novel device BiCision in comparison to the widely used UltraCision in a routine procedure ( www.clinicaltrials.gov ; study identifier NCT01806012). METHODS: Thirty LASH procedures were performed with UltraCision and BiCision after randomization of the preparation sides. The primary end point was the resection time per side and instrument. The instruments were also compared concerning blood loss and coagulation and cutting qualities as well as postoperative complications. The patients were followed for 3 months. RESULTS: Mean preparation time per side was 8.8 ± 1.8 min for BiCision and 8.3 ± 1.9 min for UltraCision (p = 0.31), which was not significantly different. Both instruments achieved complete transection without the need of additional cutting attempts. BiCision was significantly superior regarding the number of coagulations for complete hemostasis before and after the removal of the uterine corpus (before: 6.9 ± 4.8 for BiCision and 8.6 ± 4.1 for UltraCision, p = 0.047; after: 5.4 ± 1.2 for BiCision and 8.6 ± 3.2 for UltraCision, p < 0.0001) and intraoperative blood loss (score 1.07 ± 0.25 for BiCision vs. 1.63 ± 0.49 for UltraCision, p < 0.0001). Tissue sticking to the instrument occurred less often on the BiCision side (score 0.14 ± 0.35 for BiCision vs. 0.60 ± 0.81 for UltraCision, p = 0.015). BiCision showed a significantly better fixation of the tissue (grip score 0.23 ± 0.43 for BiCision vs. 1.00 ± 0.74 for UltraCision, p < 0.0001). No intraoperative or postoperative complications were seen for both instruments. CONCLUSIONS: The efficacy and quality of vessel sealing and cutting with BiCision is not inferior to the UltraCision device. Resection time was comparable, and complete hemostasis could be achieved faster in a clinical setting. Therefore, BiCision is at least as reliable as UltraCision for laparoscopic indications.

Internally gas-cooled radiofrequency applicators as an alternative to conventional radiofrequency and microwave ablation devices: an in vivo comparison.

PURPOSE: To test the efficacy of internally CO2-cooled radiofrequency (RF) ablation in vivo and to compare its effectiveness to a standard water-cooled RF probe and to a gas-cooled microwave (MW) device. METHOD AND MATERIALS: 49 ablations were performed on 15 pigs under general anesthesia using 15G monopolar CO2-cooled RF applicators, 17G monopolar water-cooled RF applicators and 15G internally CO2-cooled microwave devices. The power of the MW device was 45W, the current of the gas-cooled RF device was 1200-1600mA. At the water-cooled RF probe, maximum power of 200W was set. Ablation time was 15min. The short and long axes of the ablation zone were measured. Histological analyses and NADH-staining were performed. The diameters and the ablation volumes were compared using an analysis of variance. RESULTS: No spots of untreated tissue were observed close to the cooled needle track in any of the ablation zones. The largest short axis diameter was 3.4±0.5cm achieved with the gas-cooled monopolar applicator. With the water-cooled applicators, short axis diameter was significantly smaller, reaching 2.5±0.4cm. Gas-cooled MW probes achieved 2.9±1.0cm. The largest ablation volume was 31.5±12ml (gas-cooled RF), and the smallest was 12.7±4ml (water-cooled RF). Short/long axis ratio was largest for gas-cooled RF probes with 0.73±0.08 versus 0.64±0.04 for the water-cooled probes and 0.49±0.25 for the microwave applicator. CONCLUSION: Gas-cooled RF applicators may have a higher potential for effective destruction of liver lesions than comparable water-cooled RF systems, and may be an alternative to standard RF and MW ablation devices.

Feasibility and safety of EUS-guided cryothermal ablation in patients with locally advanced pancreatic cancer.

BACKGROUND: New therapies are needed for pancreatic cancer. OBJECTIVE: To determine the feasibility and safety of a new endoscopic treatment. Secondary endpoints were to determine effects on tumor growth measured with CT scan and to find the overall survival. DESIGN: A cohort study of patients with local progression of advanced pancreatic adenocarcinoma after neoadjuvant therapy. The cryotherm probe (CTP), a flexible bipolar device that combines radiofrequency with cryogenic cooling, was used under EUS guidance. SETTING: San Raffaele Hospital, Milan, Italy; University Medical Center, Hamburg-Eppendorf, Germany. PATIENTS: A total of 22 patients (male/female 11/11; mean age 61.9 years) were enrolled from September 2009 to May 2011. INTERVENTION: Radiofrequency heating: 18 W; pressure for cooling: 650 psi (Pounds per Square Inch); application time: depending on tumor size. MAIN OUTCOME MEASUREMENTS: Feasibility was evaluated during the procedure. A clinical and radiologic follow-up was planned. RESULTS: The CTP was successfully applied in 16 patients (72.8%); in 6 it was not possible because of stiffness of the GI wall and of the tumor. Amylase arose in 3 of 16 patients; none had clinical signs of pancreatitis. Late complications arose in 4 cases: 3 were mostly related to tumor progression. Median postablation survival time was 6 months. A CT scan was performed in all patients, but only in 6 of 16 was it possible to clearly define the tumor margins after ablation. In these patients, the tumor appeared smaller compared with the initial mass (P = .07). LIMITATIONS: Small sample of patients, difficulty of objectifying the size of the ablated zone by CT scan. CONCLUSION: EUS-guided CTP ablation is feasible and safe. Further investigations are needed to demonstrate progression-free survival and local control.