Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n > 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.

Rapid and precise delivery of cells in the urethral sphincter complex by a novel needle-free waterjet technology

OBJECTIVES

To investigate the therapy of stress urinary incontinence in a preclinical setting cells were injected into the urethrae of minipigs; however, cells injected by William's needle were frequently misplaced or lost; thus, we investigated if needle-free cell injections using a novel waterjet technology facilitates precise injections in the urethral sphincter complex.

MATERIALS AND METHODS

Porcine adipose tissue-derived stromal cells (pADSCs) were isolated from boars, expanded, labelled, and injected in the sphincter of female pigs by waterjet employing two different protocols. After incubation for 15 min or 3 days, the urethrae of the pigs were examined. Injected cells were visualised by imaging and fluorescence microscopy of tissue sections. DNA of injected male cells was verified by polymerase chain reaction (PCR) of the sex-determining region (SRY) gene. Cell injections by William's needle served as controls.

RESULTS

The new waterjet technology delivered pADSCs faster and with better on-site precision than the needle injections. Bleeding during or after waterjet injection or other adverse effects, such as swelling or urinary retention, were not observed. Morphologically intact pADSCs were detected in the urethrae of all pigs treated by waterjet. SRY-PCR of chromosomal DNA and detection of recombinant green fluorescent protein verified the injection of viable cells. In contrast, three of four pigs injected by William's needle displayed no or misplaced cells.

CONCLUSION

Transurethral injection of viable pADSCs by waterjet is a simple, fast, precise, and yet gentle new technology. This is the first proof-of-principle concept study providing evidence that a waterjet injects intact cells exactly in the tissue targeted in a preclinical in vivo situation. To further explore the clinical potential of the waterjet technology longer follow-up, as well as incontinence models have to be studied.

The waterjet necrosectomy device for endoscopic management of pancreatic necrosis: design, development, and preclinical testing (with videos)

BACKGROUND AND AIMS

Endoscopic intervention has emerged as a first-line option for management of symptomatic pancreatic necrosis, yet endoscopic debridement is limited by the lack of dedicated endoscopic tools intended for this purpose. The objectives of this study were to design and build a prototype necrosectomy device compatible for use with a flexible endoscope and capable of selective tissue fragmentation, and to test the prototype in benchtop and porcine models.

METHODS

A novel prototype, named the waterjet necrosectomy device (WAND), was designed and developed, consisting of a single-use disposable endoscopic waterjet instrument capable of waterjet selection and independent tip articulation while fitting through a 2.8-mm working channel of a standard adult upper GI endoscope. Benchtop, ex vivo, and in vivo (porcine) testing was performed in the initial stages of investigation.

RESULTS

The WAND was capable of delivering a continuous waterjet force with a surface pressure of 0.72 bar at a flow rate of 0.37 L/minute. In phase 1 of testing, the WAND was able to achieve complete fragmentation of gelatin as a surrogate for pancreatic necrosis in benchtop testing. In phase 2 of testing, the WAND was able to achieve complete fragmentation of freshly explanted human pancreatic necrosis. In phase 3 of testing for safety in fresh necropsy swine, use of the WAND resulted in no significant tissue trauma, even when irrigation was applied at closer proximity and for more extended duration than would be anticipated in clinical use.

CONCLUSION

The WAND prototype delivers irrigation capable of fragmenting necrotic debris ex vivo and avoiding trauma to healthy nontarget tissue. Planning is underway for first-in-human studies to assess the efficacy and safety of the WAND for endoscopic pancreatic necrosectomy.

Feasibility and learning curve of unsupervised colorectal endoscopic submucosal hydrodissection at a Western Center

OBJECTIVES

Colorectal endoscopic submucosal dissection (CR-ESD) is an evolving technique in Western countries. We aimed to determine the results of the untutored implementation of endoscopic submucosal hydrodissection for the treatment of complex colorectal polyps and establish the learning curve for this technique.

METHODS

This study included data from 80 consecutive CR-ESDs performed by a single unsupervised western therapeutic endoscopist. To assess the learning curve, procedures were divided into four groups of 20 each.

RESULTS

En bloc resection was achieved in 55, 75, 75 and 95% cases in the consecutive time periods (period 1 vs. 4, P = 0.003). Curative resection was achieved in 55, 75, 70 and 95%, respectively (P = 0.037). Overall, series results demonstrated R0 resection in 75% of cases, with 23.7% requiring conversion to endoscopic piecemeal mucosal resection, and 1.25% incomplete resections. Complications included perforations (7.5%) and bleeding (3.7%). Multivariate analysis revealed factors more likely to result in association with non en bloc vs. En bloc resection, where polyp size ≥35 mm [70 vs. 23.4%; odds ratio (OR) 13.2 (1.7-100.9); P = 0. 013], severe fibrosis [40 vs. 11.7%; OR 10.2 (1.2-86.3); P = 0.033] and where carbon dioxide for insufflation was not used [65 vs. 30%; OR 0.09 (0.01-0.53); P = 0.008].

CONCLUSION

CR-ESD by hydrodissection has good safety and efficacy profile and offers well tolerated and effective treatment for complex polyps. As such, this technique may be useful in the West, in centers, where previous gastric ESD is not frequent or Japanese mentoring is not possible.

Predictive mechanics-based model for depth of cut (DOC) of waterjet in soft tissue for waterjet-assisted medical applications

The use of waterjet technology is now prevalent in medical applications including surgery, soft tissue resection, bone cutting, waterjet steerable needles, and wound debridement. The depth of the cut (DOC) of a waterjet in soft tissue is an important parameter that should be predicted in these applications. For instance, for waterjet-assisted surgery, selective cutting of tissue layers is a must to avoid damage to deeper tissue layers. For our proposed fracture-directed waterjet steerable needles, predicting the cut depth of the waterjet in soft tissue is important to develop an accurate motion model, as well as control algorithms for this class of steerable needles. To date, most of the proposed models are only valid in the conditions of the experiments and if the soft tissue or the system properties change, the models will become invalid. The model proposed in this paper is formulated to allow for variation in parameters related to both the waterjet geometry and the tissue. In this paper, first the cut depths of waterjet in soft tissue simulants are measured experimentally, and the effect of tissue stiffness, waterjet velocity, and nozzle diameter are studied on DOC. Then, a model based on the properties of the tissue and the waterjet is proposed to predict the DOC of waterjet in soft tissue. In order to verify the model, soft tissue properties (constitutive response and fracture toughness) are measured using low strain rate compression tests, Split-Hopkinson-Pressure-Bar (SHPB) tests, and fracture toughness tests. The results show that the proposed model can predict the DOC of waterjet in soft tissue with acceptable accuracy if the tissue and waterjet properties are known. Graphical Abstract (Left) An overview of the problems of traditional steerable needles and the solutions provided by waterjet steerable needles. (A) Traditional tip-steerable needles and tip-bent needles suffer from poor curvature, especially in soft tissues. (B) Traditional steerable needles are unable to accomplish many bends because the cutting force only results from drastic tissue deformation. (C) The first step for realization of waterjet steerable needles is to understand and model the interaction between waterjet and soft tissues at the tip (predictive model for depth of cut). (D) Then, the equilibrium between shapes cut in the tissue and the straight elastic needle should be understood. (Right) Waterjet steerable needles in which the direction of the tissue fracture is contr olled by waterjet and then the flexible needle follows. The first step for waterjet steerable needle realization is to predict the depth of waterjet cut.

A novel waterjet technology for transurethral cystoscopic injection of viable cells in the urethral sphincter complex

AIMS

In a recent preclinical study, we noticed that injection of cells in the urethral sphincter by needle through a cystoscope under visual control frequently yielded in misplacement or loss of cells. We, therefore, investigated if a needle-free waterjet device delivers viable cells under defined settings, including injection volume and pressure, fluid velocity and transportation media, precisely through the urothelium and connective tissue close to the sphincter muscle without full penetration of the sphincter apparatus.

METHODS

Mesenchymal stromal cells (MSCs) were prepared for needle-free waterjet injections. Upon injections into liquids cell viability and yield were investigated by trypan blue dye exclusion. Upon injection into cadaveric urethral tissue samples, cells were isolated from the urethrae and expanded to prove that this novel method delivered viable cells into the tissue. MSC injections by William's needle served as controls.

RESULTS

Waterjet injections of MSCs into isotonic cell culture medium resulted in equal or better yields of viable cells when compared with needle injections. Upon injection in urethral tissue samples, the waterjet technology facilitated fast and precise injections of viable cells through urothelial, mucosal and submucosal layers to reach the sphincter muscle. By controlling the injection pressure, loss of cells due to insufficient thrust or unintended full penetration was avoided.

CONCLUSIONS

Needle-free waterjet injections deliver cells in the urethra faster and more precisely when compared with needle injections without compromising their viability. This is the first proof-of-concept study providing evidence that a waterjet transports viable cells precisely into the targeted tissue.

Selective debridement of burn wounds using hydrosurgery system

In recent years, hydrosurgery is a technology that has been applied more and more in debridement procedures. However, the selectivity of hydrosurgery to cutaneous necrotic tissues has not been proved. This study was designed to investigate the possible tissue selectivity of hydrosurgery in the debridement in burn wounds. Deep partial-thickness burns were produced on the back of porcine, and 48 hours later, both burn wounds and normal skin were debrided using the hydrosurgery system. Then tissue samples were taken, and histological staining was performed and observed under microscope. Burn wound resection rates and the normal skin damaged rates were measured. Our result indicated that the burn wounds were significantly more sensitive than the normal skin when the water pressure produced by the hydrosurgery system was set between 3000 and 5000 psi (pounds per square inch), that is, the necrotic tissue portions were debrided more easily than the normal skin tissue. Based on these data, we suggest that 3000 to 5000 psi of water pressure in the hydrosurgery system has a skin tissue selectivity in burn wounds.

Bilateral laparoscopic ureterolysis using hydrodissection in retroperitoneal fibrosis: a new application of an old technique

Objective: To describe our new laparoscopic approach in ureterolysis using the ERBEJET^® 2 device to hydrodissect the ureters in idiopathic retroperitoneal fibrosis.

Methods: Bilateral laparoscopic ureterolysis was done after medical therapy failure (steroids) in a 47 year old patient with retroperitoneal fibrosis. Ureteral stents were placed before surgery. Only five trocars were used for both sides, Toldt’s fascia was opened and the dissection was performed till the psoas muscle. The ureters were completely freed from the fibrotic tissue using the ERBEJET 2 device (pure hydrodissection). An omental wrap was passed behind the colonic flexure at the right and placed around the ureter. At the left, we closed Toldt’s fascia by running sutures back to the freed ureter.

Results: The operating time was 198 mins. The blood loss was 50 cc. The hospital stay was 3 days. The double J stents were removed at 4 weeks postoperatively. After 2 years, the patient is free of symptoms with normal creatinine level and no urinary tract obstructions.

Conclusions: Hydrodissection of the ureter in retroperitoneal fibrosis is a new application in the upper urinary tract laparoscopic approach that has not been described in literature before. It seems to offer excellent midterm outcomes. The use of ERBEJET 2 device seems to simplify the procedure and make it feasible and safe (less trauma to the ureter and more conservation of its blood supply). We believe that comparative studies are needed to assess the role of hydrodissection in ureterolysis for retroperitoneal fibrosis.

Submucosal injection with waterjet improves endoscopic mucosal resection of colorectal adenoma - a randomised controlled clinical trial

PURPOSE

Endoscopic mucosal resection (EMR) of colorectal adenomas leads to a reduced incidence of, and mortality from, colorectal carcinoma. Large adenomas are especially difficult to resect. Submucosal injection is a key part of EMR, as it allows for complete resection and decreased complications. We previously demonstrated in both animal models and a clinical trial that a focussed fluid beam applied to the mucosa creates selective fluid cushions in the submucosa selective tissue elevation by pressure (STEP). In this study, we examined the potential of this new technique compared to the standard inject and cut technique.

METHODS

This was a monocentric prospective two armed randomised controlled clinical trial comparing the STEP technique to the standard needle injection. We included patients with Yamada I and II adenomas ≥12 mm.

RESULTS

One hundred fifty-five patients were treated in the trial. With the STEP technique there was a significantly higher rate of en-bloc resection, whereas piecemeal resection was more common in the standard arm. The odds ratio of piecemeal resection was 2.422 with a 95% confidence interval of 1.163-5.045 (p value .0195). There was no significant difference in resection time between the two techniques, while there was a significant difference in resections speed for the STEP technique. There was also no difference in complication rates.

CONCLUSIONS

This study demonstrated that the new STEP technique leads to a higher rate of en-bloc resections than the standard injection technique in endoscopic mucosa resection of colorectal adenomas. The STEP technique can play an important role in the future of EMR.

A laser-induced pulsed water jet for layer-selective submucosal dissection of the esophagus

Background and aims: Conventional water jet devices have been used for injecting fluid to lift up lesions during endoscopic submucosal dissection or endoscopic mucosal resection procedures. However, these devices cannot dissect the submucosal layer effectively. Here we aim to elucidate the dissection capability of a laser-induced pulsed water jet and to clarify the mechanism of dissection with layer selectivity. Materials (Subjects) and methods: Pulsed water jets were ejected from a stainless nozzle by accelerating saline using the energy of a pulsed holmium: yttrium-aluminum-garnet laser. The impact force (strength) of the jet was evaluated using a force meter. Injection of the pulsed jet into the submucosal layer was documented by high-speed imaging. The physical properties of the swine esophagus were evaluated by measuring the breaking strength. Submucosal dissection of the swine esophagus was performed and the resection bed was evaluated histologically. Results: Submucosal dissection of the esophagus was accomplished at an impact force of 1.11-1.47 N/pulse (laser energy: 1.1-1.5 J/pulse; standoff distance: 60 mm). Histological specimens showed clear dissection at the submucosal layer without thermal injury. The mean static breaking strength of the submucosa (0.11 ± 0.04 MPa) was significantly lower than that of the mucosa (1.32 ± 0.18 MPa), and propria muscle (1.45 ± 0.16 MPa). Conclusions: The pulsed water jet device showed potential for achieving selective submucosal dissection. It could achieve mucosal, submucosal, and muscle layer selectivity owing to the varied breaking strengths.

ENDOSCOPIC GASTRIC SUBMUCOSAL DISSECTION: experimental comparative protocol between standard technique and Hybrid-Knife(r)

BACKGROUND

Endoscopic treatment of superficial gastrointestinal tumors is routinely performed, however the advantages and shortcomings of submucosal pressure-jet dissection is still debated.

OBJECTIVE

- Aiming to compare this technique with conventional submucosal dissection, a study was designed in pigs.

METHODS

- Areas of the antral mucosa of the stomach with a diameter of 2 cm2 (6 per animal) were marked, and resected by means of the hybrid-knife (experimental technique), and Flush-knife or IT-knife (controls). An ERBE ICC 300 electrosurgical unit was adopted. End-points were procedural time, complications, and quality of the resected specimen.

RESULTS

- A total of 27 interventions were conducted in five animals. Time spent with the two options was quite short, and similar: 9.5±3.1 vs 8.0±3.0 minutes (P=0.21). Complications didn't differ (three per group, not significant), and removed specimen looked adequate in both circumstances.

CONCLUSION

- The hybrid-knife technique is an acceptable alternative to submucosal dissection, showing no difference compared to the standard technique taking into consideration the procedure, the presence of complications and the quality of the resected specimen.

Comparison of O-Type HybridKnife to Conventional Knife in Endoscopic Submucosal Dissection for Gastric Mucosal Lesions

Endoscopic submucosal dissection (ESD) has been accepted as a minimal invasive alternative to surgery for localized superficial gastrointestinal neoplasms recently. However, the procedure remains to be technically challenging and time consuming. A new dissecting knife with partially insulated tip has been recently developed with built-in injection capability. The purpose of this study was to investigate whether the efficiency of ESD procedure could be improved with this new device. A total of 78 patients, who underwent ESD with gastric mucosal lesions including flat type polyps, adenoma or early gastric cancer, were randomly assigned to either ESD with O-type HybridKnife or conventional ESD knives without waterjet. Procedure time and related factors of ESD were analyzed. ESD procedure time was 43.0 (interquartile range, IQR 27.0-60.0) minutes in HybridKnife group compared to 60.5 (IQR 44.0-86.3) minutes in the control group (P = 0.001). There was no difference in the clinical outcome and the adverse event rate. The former demonstrated more favorable results in lesions ≤4 cm of specimen size (P ≤ 0.0001) and when located in the distal stomach (P = 0.001), also in lesions with fibrosis (P = 0.008). Multivariate regression analysis showed that O-type Knife (P ≤ 0.0001), specimen size (P ≤ 0.0001), and fibrosis (P ≤ 0.0001) were independent predictors of procedure time. The O-type HybridKnife yielded faster procedure time compared to the conventional knives in gastric ESD with a similar safety profile.

Use of water jet instruments in gastrointestinal endoscopy

In recent years, water jet instruments have been used in the field of gastrointestinal endoscopy, mainly in two clinical situations: Investigation and treatment under endoscopic view. Injecting water jet into the gastrointestinal lumen is helpful for maintaining a clear endoscopic view, washing away blood or mucous in the lumen or on the surface of the tip of the endoscope. This contributes to reducing time and discomfort of examination. Water jet technology is an alternative method for dissecting soft tissue; this method does not harm the small vessels or cause mechanical or thermal damage. However, its use in clinical settings has been limited to the transmucosal injection of water into the submucosal layer that elevates the mucosa to prepare for endoscopic mucosal resection or endoscopic submucosal dissection, instead of tissue dissection, which may occur because of the continuous water jet. A preclinical study has been conducted using a pulsed water jet system as an alternative method for submucosal dissection by reducing intraoperative water consumption and maintenance of dissection capability. This review introduces recent studies pertaining to using a water jet in gastrointestinal endoscopy and discusses future prospects.

Improved Techniques for Endoscopic Mucosal Resection (EMR) in Colorectal Adenoma

Background

Endoscopic therapy of colorectal adenomas and early cancers is a standard method. Besides oncological criteria, the method is limited by polyp location, size, and texture.

Method

Based on the current literature, technical modifications and developments in endoscopic mucosal resection are described.

Results

Numerous approaches exist to improve the conditions of resection, including optimisation of mucosal elevation and modification of techniques, tools, and devices.

Conclusion

Endoscopic therapy of sessile and flat colorectal polyps remains a challenge. Some of the presented modifications can help to address this challenge.

The dissection profile and mechanism of tissue-selective dissection of the piezo actuator-driven pulsed water jet as a surgical instrument: laboratory investigation using Swine liver

BACKGROUND/PURPOSE

The water jet technique dissects tissue while sparing cord-like structures such as blood vessels. The mechanism of such tissue-selective dissection has been unknown. The novel piezo actuator-driven pulsed water jet (ADPJ) system can achieve dissection with remarkably reduced water consumption compared to the conventional water jet; however, the system's characteristics and dissection capabilities on any organ have not been clarified. The purposes of this study were to characterize the physical properties of the novel ADPJ system, evaluate the dissection ability in swine organs, and reveal the mechanism of tissue-selective dissection.

METHODS

The pulsed water jet system comprised a pump chamber driven by a piezo actuator, a stainless steel tube, and a nozzle. The peak pressure of the pulsed water jet was measured through a sensing hole using a pressure sensor. The pulsed water jet technique was applied on swine liver in order to dissect tissue on a moving table using one-way linear ejection at a constant speed. The dissection depth was measured with light microscopy and evaluated histologically. The physical properties of swine liver were evaluated by breaking strength tests using tabletop universal testing instruments. The liver parenchyma was also cut with three currently available surgical devices to compare the histological findings.

RESULTS

The peak pressure of the pulsed water jet positively correlated with the input voltage (R(2) = 0.9982, p < 0.0001), and this was reflected in the dissection depth. The dissection depth negatively correlated with the breaking strength of the liver parenchyma (R(2) = 0.6694, p < 0.0001). The average breaking strengths of the liver parenchyma, hepatic veins, and Glisson's sheaths were 1.41 ± 0.45, 8.66 ± 1.70, and 29.6 ± 11.0 MPa, respectively. The breaking strength of the liver parenchyma was significantly lower than that of the hepatic veins and Glisson's sheaths. Histological staining confirmed that the liver parenchyma was selectively dissected, preserving the hepatic veins and Glisson's sheaths in contrast to what is commonly observed with electrocautery or ultrasonic instruments.

CONCLUSIONS

The dissection depth of liver tissue is well controlled by input voltage and is influenced by the moving velocity and the physical properties of the organ. We showed that the device can be used to assure liver resection with tissue selectivity due to tissue-specific physical properties. Although this study uses an excised organ, further in vivo studies are necessary. The present work demonstrates that this device may function as an alternative tool for surgery due to its good controllability of the dissection depth and ability of tissue selectivity.

ESD around the world: Europe

In Europe, endoscopic mucosal resection (EMR) is widely accepted as an appropriate diagnostic approach to obtain specimens for accurate histopathologic evaluation, which may change grading and local staging of early neoplasia determined by prior biopsies and imaging. In contrast to EMR, endoscopic submucosal dissection (ESD) allows resection of even large lesions in a single piece. Evidence on the clinical value of ESD is still limited and mainly based on data from Japan, and may not be directly applicable to Europe, where the outcome of ESD may be less favorable because of the limited Western expertise in this challenging technique.

Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife: A pilot animal study

AIM: To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model.

METHODS: Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy was performed on three non-survival pigs, by transumbilical approach, using a water-jet hybrid-knife. Under general anesthesia, the following steps detailed the procedure: (1) incision of the umbilicus followed by the passage of a double-channel flexible endsocope through an overtube into the peritoneal cavity; (2) establishment of pneumoperitoneum; (3) abdominal exploration; (4) endoscopic cholecystectomy: dissection of the gallbladder performed using water jet equipment, ligation of the cystic artery and duct conducted using nylon loops; and (5) necropsy with macroscopic evaluation.

RESULTS: Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig, with minor bleedings. The dissection times were 137 and 42 min, respectively. The total operation times were 167 and 69 min, respectively. And the lengths of resected specimen were 6.5 and 6.1 cm, respectively. Instillation of the fluid into the gallbladder bed produced edematous, distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops. There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case, leading to the operation failure.

CONCLUSION: Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation.

Experimental application of pulsed laser-induced water jet for endoscopic submucosal dissection: mechanical investigation and preliminary experiment in swine

BACKGROUND AND AIM

A current drawback of endoscopic submucosal dissection (ESD) for early-stage gastrointestinal tumors is the lack of instruments that can safely assist with this procedure. We have developed a pulsed jet device that can be incorporated into a gastrointestinal endoscope. Here, we investigated the mechanical profile of the pulsed jet device and demonstrated the usefulness of this instrument in esophageal ESD in swine.

METHODS

The device comprises a 5-Fr catheter, a 14-mm long stainless steel tube for generating the pulsed water jet, a nozzle and an optical quartz fiber. The pulsed water jet was generated at pulse rates of 3 Hz by irradiating the physiological saline (4°C) within the stainless steel tube with an holmium-doped yttrium-aluminum-garnet (Ho:YAG) laser at 1.1 J/pulse. Mechanical characteristics were evaluated using a force meter. The device was used only for the part of submucosal dissection in the swine ESD model. Tissues removed using the pulsed jet device and a conventional electrocautery device, and the esophagus, were histologically examined to assess thermal damage.

RESULTS

The peak impact force was observed at a stand-off distance of 40 mm (1.1 J/pulse). ESD using the pulsed jet device was successful, as the tissue specimens showed precise dissection of the submucosal layer. The extent of thermal injury was significantly lower in the dissected bed using the pulsed jet device.

CONCLUSION

The results showed that the present endoscopic pulsed jet system is a useful alternative for a safe ESD with minimum tissue injury.

Water-jet dissector for endoscopic submucosal dissection in an animal study: outcomes of the continuous and pulsed modes

BACKGROUND

Endoscopic submucosal dissection (ESD) allows en bloc resection of early neoplastic lesions of gastrointestinal tract. Lesions are lifted by submucosal fluid injection before circumferential incision and dissection. High-pressure fluid injection using water jet (WJ) technology is already used for lifting and dissection in surgery. The study was designed to assess WJ for ESD submucosal lifting and dissection.

METHODS

An experimental, randomized comparative, "in vivo" nonsurvival animal study on 12 pigs was designed. Stomach mucosal areas were delineated and resected using three ESD techniques: technique A-syringe injection and IT knife dissection; technique B-WJ continuous injection and IT knife dissection; technique C-WJ injection and WJ pulsed dissection. Injection and dissection speeds and complications rates were assessed.

RESULTS

Water jet continuous injection is faster than syringe injection (B faster than A, p = 0.001 and B nonsignificantly faster than C, p = 0.06). IT knife dissection is significantly faster after WJ continuous injection (B faster than A, p = 0.003). WJ pulsed dissection is significantly slower than IT knife dissection (C slower than A and B, both p < 0.001). The overall procedure speed was significantly higher and the immediate bleedings rate was significantly lower for technique B than A and C (overall procedure speed p = 0.001, immediate bleedings p = 0.032 and 0.038 respectively). There were no perforations with any technique.

CONCLUSIONS

Water jet fluid continuous injection speeds up ESD, whereas pulsed WJ dissection does not.

Endoscopic tattooing of gastrointestinal and pancreatic lesions

The intraoperative identification of the lesions found at endoscopic examination is often difficult, especially during laparoscopic surgery. At present, the most used technique for the intraoperative detection of pathological lesions is endoscopic tattooing. The large majority of studies carried out concern colorectal lesions; however, endoscopic tattooing has also been described for esophageal, gastric, small bowel and, more recently, pancreatic lesions. In this review, the authors evaluated indications, substances used, injection techniques, accuracy, safety and, finally, the risk of complications related to this procedure.

Endoscopic submucosal dissection of early gastric neoplasia with a water jet-assisted knife: a Western, single-center experience

BACKGROUND

Endoscopic submucosal dissection (ESD) of early gastric neoplasia has not yet been established in Western countries because of a lack of data and the difficult, time-consuming, and hazardous nature of the method. Some of the technical limitations may be overcome by use of a water jet-assisted knife, which allows a combination of a high-pressure water jet and electrosurgical interventions.

OBJECTIVE

To evaluate the efficacy and safety of water jet-assisted ESD (WESD) with a water jet-assisted knife in selected patients with early gastric neoplasia.

DESIGN

Single-center, prospective study.

PATIENTS

This study involved 29 consecutive patients (13 female; median age 61 years; age range 35-93 years) with early gastric neoplasia that met the expanded criteria of the Japanese Gastric Cancer Association. Histology of biopsies had shown gastric adenocarcinoma in 21 cases, adenoma in 8 case, and suspicion of a GI stromal tumor in 1 case. The median maximal diameter of the lesions was 20 mm (range 10-40 mm).

INTERVENTION

All procedures were done with patients under sedation with propofol. The water jet-assisted knife was used for setting coagulation markers around the neoplastic lesions, then for circumferential incision and dissection in combination with repeated submucosal injection of saline solution with a water jet system. Bleeding was treated with diathermia by use of the water jet-assisted knife or hemostatic forceps in case of failure or larger vessels. Clips were used for closure of perforations.

MAIN OUTCOME MEASUREMENTS

Complete resection of neoplasia, procedure time, complication and recurrence rates.

RESULTS

According to endoscopic criteria, complete resection of the targeted area could be achieved in all cases, with an en bloc resection rate of 90%. The median procedure duration was 74 minutes (range 15-402 minutes). Exchange of the device was needed in only 10 cases because of severe bleeding from larger vessels, which could be managed by use of hemostatic forceps. The 30-day morbidity rate was 4 of 30 (13.8%) because of postprocedure pain in 3 cases and delayed bleeding in 1 case. A 93-year-old patient died the night after WESD without evidence of a procedure-related complication. Histology of the resected specimens showed adenocarcinoma in 20 cases, adenoma in 7, no neoplasia in 2, and a plasmacytoma in 1. Complete resection (R0) was histologically confirmed in 18 of 28 patients (64.3%) with resected neoplastic specimens. A horizontal or vertical neoplasia-free margin could not be confirmed in 9 cases and 1 case, respectively. Complete local remission of neoplasia was achieved in 25 of 28 patients (89.3%) who were followed over a median period of 22 months (range 6-44 months). In 1 patient, a metachronous gastric adenocarcinoma was identified 54 weeks after initial WESD.

LIMITATIONS

Noncontrolled study with a limited number of patients.

CONCLUSION

The use of a water jet-assisted knife simplifies ESD because exchange of devices is rarely needed. WESD promises to be effective and safe. The study demonstrates that the high rates of en bloc resection of early gastric neoplasia reported in Asia can be reproduced in Western referral centers. However, histology may not always confirm complete resection of horizontal tumor margins. In spite of the unfavorable histology results, the high rate of complete local remission of neoplasia promises that surgical treatment of early gastric neoplasia can be avoided in the majority of cases.

Selective tissue elevation by pressure for endoscopic mucosal resection of colorectal adenoma: first clinical trial

BACKGROUND

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection of large lateral spreading tumors currently are technically limited by complications such as bleeding, perforation, and disturbed large procedural sites, leading to incomplete resection and secondary surgery. Further technical improvements are necessary. The authors previously demonstrated the effectiveness of a focused water jet for elevation of the lamina submucosa in animal studies. For the first time, the clinical application of selective tissue elevation by pressure (STEP) for the treatment of colorectal adenomas as a prospective single-arm human trial is presented.

METHODS

This trial evaluated 59 patients who had primary colorectal adenomas with diameters exceeding 12 mm classified as 0-IIa or 0-IIb according to Paris classification. A submucosal cushion was created with a flexible water jet applicator using the Helix HydroJet. The adenoma was subsequently resected with a mucosal resection snare. All results were recorded. The resected specimens were assessed histologically.

RESULTS

A total of 59 patients underwent resection of 70 lesions with a maximum diameter of 80 mm (mean, 27 mm). Submucosal elevation with the water jet dissector was possible in all cases and locations from the pectinate line to the ileocecal valve. Of the 70 lesions, 64 (91%) were resected completely in one session. Histologically, the resected specimens were found to be adenocarcinomas (n = 2, 3%), adenomas with high-grade intraepithelial neoplasia (n = 24, 34%), adenomas with low-grade intraepithelial neoplasia (n = 38, 54%), and hyperplastic polyps (n = 6, 9%). Hemostasis during the resection was necessary in 24 cases (34%). No perforation required surgical intervention.

CONCLUSION

This first clinical trial to analyze STEP technique demonstrated that STEP used to elevate large mucosal lesions in any location is feasible and facilitates EMR for colorectal adenoma.

Prospective, randomized study of conventional versus HybridKnife endoscopic submucosal dissection methods for the esophagus: an animal study

BACKGROUND

Endoscopic submucosal dissection (ESD) increases en bloc and histologically complete resection rate of neoplastic mucosal tumors but is technically more demanding than EMR. Limited data are available comparing the efficacy and safety of a new ESD designed to overcome these limitations and conventional ESD (C-ESD) techniques.

OBJECTIVE

To compare the safety, efficacy, and operation time of the new HybridKnife ESD (HK-ESD) with C-ESD in the esophagus.

DESIGN

Prospective, randomized, controlled study.

SETTING

Animal research laboratory.

SUBJECTS

Seventeen anesthetized Yorkshire pigs.

INTERVENTIONS

Removal of a 4-cm length of half-circumference esophageal mucosa by C-ESD with Hook knife or Flexknife versus HK-ESD.

MAIN OUTCOME MEASUREMENTS

Procedure time, en bloc and complete resection rate, and complications (bleeding and perforation).

RESULTS

All resections were completed en bloc. Procedure time was shorter in C-ESD. However, it was similar after 12 procedures. Significantly more bleeding occurred during C-ESD (28 vs 12, P = .0007). Histological muscularis propria injuries occurred with equal frequency (16 vs 17) and were mostly seen during the first 11 procedures. There were 3 perforations (2 endoscopic, 1 histological), all with C-ESD.

LIMITATIONS

Nonsurvival study, use of 2 conventional knives, no training period for a new procedure.

CONCLUSIONS

The HK-ESD technique was equally effective as the C-ESD technique for successful en bloc resection and was safer with less bleeding and perforation. Although procedure time was longer in HK-ESD, the difference became nonsignificant after 12 procedures.

New applicator improves waterjet dissection quality

OBJECTIVE

Waterjet dissection is accomplished with Helix Hydro-Jet, but a new device with improved operative handling and potentially superior dissection qualities has been developed.

MATERIALS AND METHODS

Eighty-four fresh cadaveric pig brains were simultaneously cut with Helix Hydro-Jet and Erbejet 2. A commonly used applicator and a new applicator for the Helix Hydro-Jet were directly compared to the new Erbejet 2. Under standardised conditions, different pressure levels were applied to the brain surface without arachnoids. Technical features, cutting depth, tissue damage and differences of applicators were examined.

RESULTS

Microscopic analysis of cutting depth revealed different dissection characteristics of both the devices. With the standard applicators, waterjet cutting depth was shown to be deeper and with more foaming using the Helix Hydro-Jet compared to that of the Erbejet 2. With the new applicators, less foaming and a lower and more linear increased cutting depth were observed with the Helix Hydro-Jet, very similar to the superior qualities shown by the Erbejet 2.

CONCLUSIONS

The new developed applicator of the Erbejet 2 also improves the intraoperative results of the so far applied Helix Hydro-Jet. The new Erbejet 2 provides some advantages for practicability; but in combination with the new applicator, the Helix Hydro-Jet accomplished almost identical superior dissection qualities of the Erbejet 2.

Waterjet dissection in pediatric cranioplasty

OBJECT

Waterjet dissection has been shown to separate tissues of different resistance, with preservation of blood vessels. In cranioplasty, separation of subcutaneous tissue and dura mater is often difficult to achieve because the various tissue layers strongly adhere to each other after decompressive craniotomy. In the present study, the potential advantages and drawbacks of the waterjet technique in cranioplasty after craniectomy and duraplasty are addressed.

METHODS

The waterjet effect on fresh human cadaveric dura mater specimens as well as on several dural repair patches was tested in vitro under standardized conditions, with waterjet pressures up to 80 bar. Subsequently, 8 pediatric patients (5 boys, 3 girls; mean age 9.9 years, range 1.2-16.7 years) who had been subjected to decompressive craniectomy (7 with duraplasty including bovine pericardium as a dural substitute, 1 without duraplasty in congenital craniosynostosis) underwent waterjet cranioplasty. The waterjet was used to separate the galea and the dura mater. The technique was applied tangentially between the dura and the galea, with different pressure levels up to 50 bar.

RESULTS

In vitro, fresh cadaveric human dura mater as well as 2 different dural repair substitutes showed a very high resistance to waterjet dissection up to 80 bar. The human dura and the various substitutes were dissected only after long-lasting exposure to the waterjet. Human dura was perforated at pressures of 60 bar and higher. Bovine pericardium dural substitute was perforated at pressures of 55 bar and higher. Artificial nonabsorbable polyesterurethane dural substitute was dissected at pressures of 60 bar and higher. In the clinical setting, the waterjet was able to separate galea and dura with minimal bleeding. No blood transfusion was required. Dissection of scarred tissue was possible by a waterjet of 40 bar pressure. Tissue layers were stretched and separated by the waterjet dissection, and a very reliable hemostasis resulted. This resulted in an effective reduction of bleeding, with < 60 ml blood loss in 7 of the 8 cases. Neither a dural tear nor a perforation of any duraplasty occurred during operative preparation. There were no operative or postoperative complications.

CONCLUSIONS

The experimental and clinical data show that waterjet separation of dura mater, dural substitute, and galea can be performed with a high level of safety to avoid dural tears. The waterjet dissection stretches tissue layers, which results in a reliable hemostasis effect. This potentially results in an effective reduction of surgical blood loss, which should be the focus of further studies.

A novel device for endoscopic submucosal dissection that combines water-jet submucosal hydrodissection and elevation with electrocautery: initial experience in a porcine model

BACKGROUND

Endoscopic submucosal dissection requires a high degree of endoscopic skill and specifically designed dissecting instruments.

OBJECTIVE

To describe the technique for endoscopic submucosal dissection when using the ERBE Hybrid Knife, which combines an ultrafine high-pressure water jet with an electrocautery needle.

DESIGN

Descriptive study (ex vivo and in vivo porcine esophagus, stomach, and colon).

INTERVENTIONS

The only instrument used for the dissection was the ERBE Hybrid Knife. The high-pressure water jet was used at a pressure between 45 and 60 bar for creating submucosal fluid elevation. After this, circumferential mucosal incisions and submucosal dissection were performed with the FORCED COAG and ENDOCUT D modes of the same device. The water jet was used intermittently during the dissection process.

MAIN OUTCOME MEASUREMENTS

At the end of the in vivo experiments, animals were killed and the organs removed for evaluation.

RESULTS

Multiple endoscopic submucosal dissection procedures were successfully performed. It was possible to create submucosal fluid cushions rapidly. Repeated fluid injections during dissection were easily facilitated with the same device. All ex vivo gastric endoscopic submucosal dissections of 50 x 40-mm lesions were completed within 10 minutes. In the in vivo studies, the mean size of the gastric and colonic specimens was 3.7 +/- 2.1 x 2.3 +/- 1 cm, and the dissections were completed within 8 minutes. No thermal injury was observed on the serosa, and no perforations were detected.

CONCLUSIONS

Endoscopic submucosal dissection can be safely and effectively achieved in a porcine model with the ERBE Hybrid Knife and should be considered a suitable device for this procedure in humans.

A randomised study of hydro-jet vs. needle injection for lifting colorectal lesions prior to endoscopic resection

BACKGROUND

Submucosal lifting of lesions prior to endoscopic resection is crucial to reduce complications and improve the technical feasibility of the procedure.

AIM

To compare a self-assembled hydro-jet system vs. standard needle injection for tissue elevation prior to endoscopic resection of colorectal lesions.

METHODS

Randomised study performed at a single tertiary care institution. Consecutive patients with colonoscopic diagnosis of sessile polyps or non-polypoid lesions >5 mm or laterally spreading tumours.

OUTCOME MEASURES

successful elevation, time to proper elevation, completeness of excision, cautery damage, and general histological diagnostic quality (blinded pathologic assessment).

RESULTS

79 patients were randomised to hydro-jet (40 patients, group A) and needle (39 patients, group B) elevation. Successful elevation was achieved in 97.5% and 94.8%, respectively. Time to proper elevation was 8+/-5 s vs. 18+/-3 s (p<0.05). In group A, histology showed selective accumulation of fluid in the submucosa with intact collagen fibres. Damage to muscularis mucosa was never noted in the specimens of group A and in 7 cases of group B (p<0.01). Artefacts from "cautery effect" were very limited. Radial margins of resection could be adequately evaluated in all cases and were negative.

CONCLUSIONS

The hydro-jet system is as effective and safe as standard needle injection for tissue elevation prior to endoscopic resection of colorectal lesions, but it is significantly faster.

Self-assembled hydro-jet system for submucosal elevation before endoscopic resection of nonpolypoid colorectal lesions (with video)

BACKGROUND

Endoscopic resection of colorectal nonpolypoid lesions requires adequate submucosal lifting of the lesion.

OBJECTIVE

To evaluate a self-assembled hydro-jet system for tissue elevation to improve endoscopic resection of colorectal nonpolypoid lesions.

DESIGN

Prospective study.

SETTING

Single-center teaching hospital.

MAIN OUTCOME MEASUREMENTS

Efficacy and safety of the hydro-jet system and rate of complete resection.

RESULTS

The system was clinically applied in 31 patients to remove a total of 34 lesions throughout the colon. An adequate submucosal fluid cushion was achieved in all but 1 case without any lifting-associated complications. Complete endoscopic resection was possible in all 33 lifted lesions by using a snare. The size of the resected lesions ranged from 7 to 60 mm. Major intraprocedure bleeding occurred in only 1 case. No perforation or late bleeding was recorded. Histological examination showed a selective accumulation of fluid in the submucosa with edema and dissociation of submucosal structures, with no damage to the muscularis mucosa and very limited "burn effect" hampering assessment of radial margins.

LIMITATIONS

Lack of controls.

CONCLUSIONS

This inexpensive system allows safe and rapid submucosal lifting of colorectal nonpolypoid lesions to assist endoscopic resection.

First experimental results with a new waterjet dissector: Erbejet 2

BACKGROUND

Waterjet dissection represents a useful technique for many surgical procedures. In this experimental study, the technical features and dissection qualities of the new Erbejet 2 with its new pump and nozzle applicator system are evaluated for its neurosurgical use compared to the established Helix Hydro-Jet.

METHODS

One hundred twenty-six fresh cadaveric pig brains were simultaneously cut with the Helix Hydro-Jet and Erbejet 2. Different pressure levels were applied to cerebral tissue with and without meninges, cerebellum and brainstem. Additionally, dissection characteristics of various cutting media were investigated.

FINDINGS

There was a nearly equal dissection quality at up to 10 bar of both instruments. In contrast to the Helix Hydro-Jet, Erbejet 2 application at higher pressures resulted in an almost linear increase of dissection depth with a small standard deviation. Smoother cutting margins and less foaming were found. Preserved vessels were observed with both devices. Hydroxyaethyl starch led, in contrast to Ringer's solution and isotonic saline solution, to increased dissection width and more foaming.

CONCLUSIONS

The new Erbejet 2 is more precise, with almost linear correlation of pressure and dissection depth compared to the Helix Hydro-Jet. Less foaming and the possible application of various separating media are a considerable advantage. All things considered, the new Erbejet 2 offers more options to enlarge the field of neurosurgical indications for waterjet dissection.

Investigation of the thermal tissue effects of the argon plasma coagulation modes "pulsed" and "precise" on the porcine esophagus, ex vivo and in vivo

BACKGROUND

Argon plasma coagulation (APC) is a monopolar, noncontact, thermal procedure that is widely used in therapeutic endoscopy. Systematic investigations of the tissue damage ex vivo and in vivo with the new, second-generation APC modes are lacking.

OBJECTIVE

The aim of this study is to compare the tissue effects of the pulsed effect 2 and precise APC modes.

DESIGN AND SETTING

Ex vivo and in vivo animal model.

SUBJECTS

This study involved 3 explanted porcine esophagi and 8 pigs under general anesthesia.

INTERVENTION

APC application on 3 explanted esophagi and during esophagoscopy.

MAIN OUTCOME MEASUREMENTS

The tissue effect was subjected to histological and statistical investigation.

RESULTS

In vivo, a well known type of superficial tissue damage (type A) of the tunica mucosa and a new injury pattern (type B) limited to the tunica muscularis, were found. Ex vivo, only type A injuries were seen. Thermal injury of the tunica muscularis was significantly lower with precise APC compared with pulsed APC in vivo. The pulsed effect 2 shows a positive correlation between the penetration depth and the power (r = 0.38, P < .0002) or application time for the highest power setting used (40 W, r = 0.77, P < .0001). This correlation could not be detected with precise APC because of its very superficial tissue effect.

LIMITATIONS

This was an animal study. The distance of the APC probe to the esophagus may have varied between applications in vivo.

CONCLUSION

Thermal damage by APC of the esophageal tunica muscularis seems to be underestimated ex vivo. The extent of tissue injury was significantly lower with precise APC than with pulsed APC, indicating that precise APC may be suitable for the treatment of particularly thermosensitive, thin-wall anatomy.

Randomized controlled study of EMR versus endoscopic submucosal dissection with a water-jet hybrid-knife of esophageal lesions in a porcine model

BACKGROUND

Endoscopic submucosal dissection (ESD) seems to be more effective than EMR for curative resection of GI mucosal neoplasia. However, ESD is technically difficult, hazardous, and time consuming. New technologies may overcome these drawbacks.

OBJECTIVE

Our purpose was to compare a new simplified ESD technique with conventional EMR.

DESIGN

Prospective, randomized, and controlled trial in anesthetized pigs.

METHODS

A total of 25 esophageal areas with a diameter of 20 mm were marked with coagulation points in 6 pigs under general anesthesia. These lesions were then randomized to either EMR by use of the cap technique or ESD. Submucosal injection of saline solution was used for both methods. ESD was performed with a hybrid-knife (ESDH), which allows cutting and coagulation as well as a needleless, tissue-selective hydrodissection through an axial water-jet channel with a preselected pressure by using a high-pressure water-jet system (ErbeJet 2). Intraoperative bleedings were treated with hemostatic forceps.

MAIN OUTCOME MEASUREMENTS

A comparison of the rates of complete resection of the lesions, the number and the size of resected specimens, the complication rate, and the procedural duration.

RESULTS

Thirteen lesions were randomized to EMR and 12 to ESDH. ESDH achieved complete resection significantly more frequently than EMR (10/12 vs 6/13; P = .05). All ESDH resections were performed as a single piece, whereas a mean (SD) of 2.5 +/- 0.9 resections were needed for EMR (P < .05). The mean (SD) areas of the specimen were 3.63 +/- 1.20 cm(2) in the ESDH group and 1.83 +/- 0.78 cm(2) in the EMR group (P < .0001). ESDH was performed with a larger amount of fluid for injection and hydrodissection compared with EMR (78.1 +/- 32.8 mL vs 20.9 +/- 7.6 mL; P < .001). The procedural duration was longer for ESDH than for EMR (28.2 +/- 11.9 minutes vs 12.2 +/- 4.9 minutes; P < .001). ESDH and EMR caused bleedings in 6 of 12 and 5 of 13 of the cases (P = .09), respectively. Hemostasis could be achieved in all cases. There was no perforation in either group.

LIMITATIONS

Resection of artificial non-neoplastic lesions, small numbers, an animal trial.

CONCLUSIONS

ESDH achieves complete resection of esophageal lesions significantly more frequently with a fewer number of specimens than EMR. ESDH is more time consuming, but the procedural duration seems to be shorter than conventional ESD because there is no need for exchange of devices for injection and cutting. The easy use of water-jet-assisted repeated injections of fluids may explain why ESDH was as safe as EMRC.

Combination of water-jet dissection and needle-knife as a hybrid knife simplifies endoscopic submucosal dissection

BACKGROUND

The safety and efficacy of endoscopic submucosal dissection (ESD) is very dependent on an effective injection beneath the submucosal lamina and on a controlled cutting technique. After our study group demonstrated the efficacy of the HydroJet in needleless submucosal injections under various physical conditions to create a submucosal fluid cushion (Selective tissue elevation by pressure = STEP technique), the next step was to develop a new instrument to combine the capabilities of an IT-Knife with a high-pressure water-jet in a single instrument. In this experimental study, we compared this new instrument with a standard ESD technique.

METHODS

Twelve gastric ESD were performed in six pigs under endotracheal anesthesia. Square areas measuring 4-cm x 4-cm were marked out on the anterior and posterior wall in the corpus-antrum transition region. The HybridKnife was used as an standard needle knife with insulated tip (i.e., the submucosal injection was performed with an injection needle and only the radiofrequency (RF) part of the HybridKnife was used for cutting (conventional technique)) or the HybridKnife was used in all the individual stages of the ESD, making use of the HybridKnife's combined functions (HybridKnife technique). The size of the resected specimens, the operating time, the frequency with which instruments were changed, the number of bleeding episodes, and the number of injuries to the gastric wall together with the subjective overall assessment of the intervention by the operating physician were recorded.

RESULTS

The resected specimens were the same size, with average sizes of 16.96 cm(2) and 15.85 cm(2) resp (p = 0.8125). Bleeding episodes have been less frequent in the HybridKnife group (2.83 vs. 3.5; p = 0.5625). The standard knife caused more injuries to the lamina muscularis propria (0.17 vs. 1.33; p = 0.0313). The operating times had a tendency to be shorter with the HybridKnife technique (47.18 vs. 58.32 minute; p = 0.0313).

DISCUSSION

The combination of a needle-knife with high-pressure water-jet dissection improved the results of endoscopic submucosal dissection in this experimental setting. Because the frequency of complications is still high, further improvements to the instrument are necessary.

Blood coagulation and cancer: thrombosis and survival, clinical relevance and impact. An introduction

There is a strong association between deep venous thrombosis and cancer. In this review, we will discuss the increased incidence of cancer following an idiopathic venous thrombotic event (VTE) and the increased incidence of VTE and its recurrence in cancer patients. Furthermore, we will review the adverse impact VTE has on cancer patients' morbidity and mortality. Finally, the potential influence of anticoagulation on survival of cancer patients is discussed. Although the data are encouraging, anticoagulation is still of limited value for routine clinical practice in anticancer treatment.

Endoscopic resection of early oesophageal and gastric neoplasia

In the last decades, endoscopic treatment of early neoplastic lesions in the oesophagus and stomach has evolved as a valid and less invasive alternative to surgical resection. Endoscopic resection (ER) is the cornerstone of endoscopic therapy. Apart from the curative potential of ER, by removing neoplastic lesions, ER may also serve as a diagnostic tool. The relatively large tissue specimens obtained with ER enable accurate histological staging of a lesion, allowing for optimal decision making for further patient management. ER was pioneered in Japan, mainly for the resection of gastric lesions and squamous oesophageal neoplasia, and also Western countries have been increasingly implementing ER in the treatment of early gastro-oesophageal neoplasia, mostly associated with Barrett oesophagus. In this review we will give an overview of the different techniques that have been developed and modified for ER of early gastro-oesophageal neoplasia, and we will discuss the indications for ER in the oesophagus and stomach.

Submucosal cushioning with water jet before endoscopic mucosal resection : Which fluids are effective?

BACKGROUND

Several new techniques have recently been described that allow the endoscopic mucosal resection even of broad-based flat lesions in the gastrointestinal tract. The technique recently described by us of using a water jet dissector (Helix HydroJet) for a selective deposition of liquid in the submucosal lamina has now been combined with different substances, and their effects have been compared.

MATERIAL AND METHODS

Gastroscopies were carried out in 8 pigs under intubation anesthesia, and 2 submucosal cushions each were created in the stomach using one out of 4 test substances (gelatin, glucose 50, hydroxyethyl starch [HES] 10%, dextran 40), as well as one cushion of isotonic saline solution placed in each area via the Helix HydroJet). The height of the submucosal cushions was intermittently measured over a period of 40 or 20 min, respectively, by miniprobe endosonography. In 7 of the animals the stomach was subsequently subjected to mucosal resection. The specimens and the gastric wall were histologically assessed to evaluate the localization of the liquid cushion and the effect on adjacent layers of the gastric wall.

RESULTS

All test substances produced strictly selective liquid cushions in the submucosa. With HES 10% and dextran the maximum height of the cushions initially increased and then decreased during the further course to an average of 90% of the initial height within 40 min. Isotonic saline solution showed the most rapid decrease in height (72% after 20 min). The histological assessment confirmed the selective nature of the liquid deposit in the submucosa.

DISCUSSION

Plasma expanders produced cushions that initially increased in height but then remained constant for a longer period than cushions produced using glucose 50, gelatin, or isotonic saline solution. The combination of transmucosal jet application for elevation of the mucosa with plasma expanders is therefore an interesting approach to optimize endoscopic mucosal resections.