Carbon dioxide submucosal injection cushion: an innovative technique in endoscopic submucosal dissection

Nanodrugs systems for therapy and diagnosis of esophageal cancer

With the increasing incidence of esophageal cancer, its diagnosis and treatment have become one of the key issues in medical research today. However, the current diagnostic and treatment methods face many unresolved issues, such as low accuracy of early diagnosis, painful treatment process for patients, and high recurrence rate after recovery. Therefore, new methods for the diagnosis and treatment of esophageal cancer need to be further explored, and the rapid development of nanomaterials has brought new ideas for solving this problem. Nanomaterials used as drugs or drug delivery systems possess several advantages, such as high drug capacity, adjustably specific targeting capability, and stable structure, which endow nanomaterials great application potential in cancer therapy. However, even though the nanomaterials have been widely used in cancer therapy, there are still few reviews on their application in esophageal cancer, and systematical overview and analysis are deficient. Herein, we overviewed the application of nanodrug systems in therapy and diagnosis of esophageal cancer and summarized some representative case of their application in diagnosis, chemotherapy, targeted drug, radiotherapy, immunity, surgery and new therapeutic method of esophageal cancer. In addition, the nanomaterials used for therapy of esophageal cancer complications, esophageal stenosis or obstruction and oesophagitis, are also listed here. Finally, the challenge and the future of nanomaterials used in cancer therapy were discussed.

Potential of temperature-response collagen-genipin sol as a novel submucosal injection agent for endoscopic resection: Acute and chronic phase study using living animals

OBJECTIVES

We proposed a novel temperature-response collagen sol as a submucosal injection agent for endoscopic resection (ER) using pepsin-solubilized collagen (PSC) and genipin (Ge) in a prior study. This study aimed to evaluate the usefulness and safety of the sol (PSC/Ge) in acute and chronic phase experiments using living animals.

METHODS

In experiment 1, we performed endoscopic submucosal dissection (ESD) for six pigs using normal saline (NS), sodium hyaluronate (SH), and PSC/Ge. We compared the required amount of each agent per unit area and procedure time. In experiment 2, we created artificial ulcers with endoscopic mucosal resection (EMR) for five pigs using NS and PSC sol. We compared the artificial ulcer residual rate at 7 and 14 days after EMR, and the scarring rate at 14 days after EMR.

RESULTS

The required amount of agents per unit area for PSC/Ge (0.8 ± 0.8 mL/cm² ) and SH (1.1 ± 0.8 mL/cm² ) were significantly smaller than that for NS (1.8 ± 0.7 mL/cm² ). The total procedure time did not have a statistical difference. The artificial ulcer residual rates were 47.3 ± 0.7% for NS and 40.3 ± 0.7% for PSC/Ge on day 7 (P = 0.51), and 15.0 ± 0.1% for NS and 10.2 ± 0.1% for PSC/Ge sol on day 14 (P = 0.35). The scarring rate on day 14 was 10% for NS and 20% for PSC/Ge.

CONCLUSION

We demonstrated the feasibility of a novel temperature-response collagen gel as a submucosal injection agent for ER in the acute and chronic phase animal experiment.

Off-label use of 0.4 % sodium hyaluronate teardrops: a safe and effective solution for submucosal injection in gastric endoscopic submucosal dissection

Background and study aims  Submucosal (SM) injection is a critical step in endoscopic submucosal dissection (ESD). In Japan, use of viscous solutions such as sodium hyaluronate are recommended; the commercially product available is MucoUp (Seikagaku Co. and Boston Scientific Japan Co., Japan). Nevertheless, MucoUp is expensive and unavailable in many Western countries. For the past 8 years, we have been using low-cost sterile teardrops solution composed of 0.4 % sodium hyaluronate (Adaptis Fresh, Legrand Laboratory, Brazil). This solution is readily available in drugstores with a cost of approximately US$ 10.00 for each 10-cc bottle. The aim of this study was to present the clinical outcome with off-label sodium hyaluronate use for SM injection in gastric ESD. Patients and methods  A single-center retrospective study of collected data investigating consecutive patients that underwent gastric ESD between 2012 and 2019. ESD was performed using 0.4 % sodium hyaluronate teardrop for SM injection and Flush Knife BT 2.5 (Fujifilm Co., Japan). The following data were analyzed: clinical-pathological features, en-bloc, R0 and curative resection rate, procedure duration, adverse events, and clinical outcome. Results  ESD was performed with sodium hyaluronate for submucosal injection in 78 patients. The en-bloc resection rate and R0 resection rate were 96.1 % and 92.3 %, respectively. The curative resection rate for epithelial lesions was 83.8 %. Adverse events occurred in 5 cases (6.3 %): delayed bleeding (3.8 %, 3 cases) and perforation (2.5 %, 2 cases); all managed successfully by clipping and thermal coagulation. The mean volume of sodium hyaluronate solution used per patient was 10 cc (SD: ± 8 cc). During follow-up (mean: 17 months; SD: ± 14.5 months), two patients developed metachronous lesions (2.5 %). Conclusions  Off-label use of teardrops with 0.4 % sodium hyaluronate for submucosal injection was demonstrated to be safe and able to provide an effective submucosal cushion that facilitates SM dissection in gastric ESD procedures.

Viscosity and degradation controlled injectable hydrogel for esophageal endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is a common procedure to treat early and precancerous gastrointestinal lesions. Via submucosal injection, a liquid cushion is created to lift and separate the lesion and malignant part from the muscular layer where the formed indispensable space is convenient for endoscopic incision. Saline is a most common submucosal injection liquid, but the formed liquid pad lasts only a short time, and thus repeated injections increase the potential risk of adverse events. Hydrogels with high osmotic pressure and high viscosity are used as an alternate; however, with some drawbacks such as tissue damage, excessive injection resistance, and high cost. Here, we reported a nature derived hydrogel of gelatin-oxidized alginate (G-OALG). Based on the rheological analysis and compare to commercial endoscopic mucosal resection (EMR) solution (0.25% hyaluronic acid, HA), a designed G-OALG hydrogel of desired concentration and composition showed higher performances in controllable gelation and injectability, higher viscosity and more stable structures. The G-OALG gel also showed lower propulsion resistance than 0.25% HA in the injection force assessment under standard endoscopic instruments, which eased the surgical operation. In addition, the G-OALG hydrogel showed good in vivo degradability biocompatibility. By comparing the results acquired via ESD to normal saline, the G-OALG shows great histocompatibility and excellent endoscopic injectability, and enables create a longer-lasting submucosal cushion. All the features have been confirmed in the living both pig and rat models. The G-OALG could be a promising submucosal injection agent for esophageal ESD.

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Injectable gel with controlled viscosity.

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Injectable gel with controlled degradation.

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Making esophageal submucosal liquid cushion.

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Potential treatment for early esophageal cancer.

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Big animal in-situ imaging.

Potential of temperature-response collagen-genipin sols as a novel submucosal injection material for endoscopic resection

Background and study aims  We developed a novel submucosal (SM) injection material that contained pepsin-solubilized collagen (PSC), genipin (Ge) and phosphate buffer (PB). The aim of this study was to validate safety and usability of it for endoscopic resection (ER). Materials and methods  In preliminary studies, 1) appropriate warming time and concentration of Ge, and concentration of NaCl in PB, 2) storage modulus of PSC, Ge, and PB mixture (PSC/Ge), and PSC as a mechanical property, 3) histological finding after injection, and histological toxicity of PSC/Ge was evaluated. We injected PSC/Ge, PSC, sodium hyaluronate (SH), dextrose (DW), and normal saline (NS) into SM of resected porcine stomach. We compared mean height of mucosal elevation after immediate injection (MH) and mean retaining rate at 60 minutes (MR) as ex vivo study. Results  Optimal condition of PSC/Ge was Ge 5.5 mMol with 24 hours worming time and NaCl 280 mMol. PSC/Ge had better mechanical property than PSC. It was efficiently integrated and confined to the SM with acceptable toxicity. MH of PSC/Ge (5.1 ± 0.74 mm) and PSC (4.8 ± 0.84 mm) were significantly higher than NS (3.2 ± 0.84 mm). MR of PSC/Ge (100 ± 0.0%) was significantly higher than NS (61.7 ± 11.2%), DW (58.3 ± 11.8%) and SH (61.8 ± 8.6%). Conclusion  PSC/Ge and PSC has potential to be safe and usable for ER. PSC/Ge was better than PSC because of better mechanical property than PSC.

Thermoresponsive aerification and tissue vacuolization for facilitating endoscopic submucosal resection

BACKGROUND AND AIMS

Mucosal lifting and its persistence are critical for maintaining the operational space and preventing perforation in endoscopic operation. Although numerous agents have been investigated, optimization is still required for improving their clinical performance. In the present study, we proposed a novel concept of thermoresponsive aerification and tissue vacuolization for submucosal injection.

METHODS

Lifting performance and operational condition were first evaluated in porcine stomachs in vitro and rabbits in vivo. Dodecafluoropentane (DDFP) injection dosage, lifting persistency and operational assistance were quantitatively recorded. Gross and histological pathology were also analyzed to identify DDFP acute toxicity and long-term safety. The endoscopic submucosal dissection (ESD) procedure with DDFP was carried out on pigs in vivo to confirm its operational feasibility, efficacy, and safety.

RESULTS

Dodecafluoropentane aerification could achieve better mucosal lift with lower dosage (1% of normal saline dosage). Thermoresponsive DDFP aerification could provide continuous replenishment and longer persistence. Meanwhile, its tissue vacuolization effect significantly facilitated submucosal tissue dissection in in vitro study. Similar performance was verified in vivo. The particular vacuole-like submucosal structure was seen after DDFP onset, which also promoted reepithelization and wound healing. No tissue damage, gas embolism, biotoxicity, and physicochemical risk were observed.

CONCLUSION

Bioinert DDFP was feasible, efficient, and safe as the novel submucosal lifting candidate.

Rebamipide solution: a novel submucosal injection material to promote healing speed and healing quality of ulcers induced by endoscopic submucosal dissection

BACKGROUND AND AIMS

Rebamipide is administered perorally to protect the gastric mucosa. We assessed the efficacy and safety of a novel rebamipide solution as a submucosal injection material for endoscopic submucosal dissection (ESD) using an in vivo porcine model.

METHODS

An endoscopist blinded to the test agents performed ESDs of hypothetical 30 mm lesions using a 2% rebamipide solution at 2 sites (rebamipide group) and a saline solution at 2 other sites (control group) in the stomachs of 8 pigs. The technical outcomes were compared between the 2 groups. The gastric ulcer stages were evaluated by endoscopy once weekly for 4 weeks after the ESD to determine the healing score (1-6). The pigs were killed at 1 week (n = 2), 2 weeks (n = 2), and 4 weeks (n = 4) after the ESD for pathologic evaluation of ESD-induced ulcers and scarring.

RESULTS

There were no significant differences in any of the technical outcomes between the 2 groups, and no adverse events related to the ESD in any of the animals. The healing score was significantly higher in the rebamipide group than in the control group at 2 weeks (P = .027), 3 weeks (P = .034), and 4 weeks (P = .012). In the histopathologic assessment, fibrosis was significantly less extensive in the rebamipide group than in the control group at 2 weeks (P = .02) and 4 weeks (P = .04).

CONCLUSIONS

The rebamipide solution appeared to promote both the speed and quality of healing of ESD-induced ulcers by suppressing fibrosis.

Thermo-sensitive isopentane aerification for mucosal lift during endoscopic resection in animal models (with video)

BACKGROUND AND AIMS

Mucosal lift is critical for successful endoscopic treatment. Normal saline (NS) solution is widely used as the submucosal filler, but its short persistency restricts clinical endoscopic submucosal dissection (ESD). In this study, thermo-sensitive isopentane was introduced for submucosal injection. With a boiling point at 27.8°C, liquid isopentane can be easily applied, and gasification inflation can provide great support for submucosal lifting at body temperature. The feasibility and efficiency of isopentane were evaluated in this study.

METHODS

Porcine stomachs were used for in vitro evaluation. A 37°C water bath was used to mimic body temperature. Compared with NS, isopentane was studied for its lifting performance, including injection dosage, persistence of lifting strength, and efficacy for assisting submucosal dissection. The changes in submucosal tissue were also compared. For in vivo evaluation, rats were used to further compare the differences between isopentane and NS, including lifting efficacy, pathologic effect, and safety.

RESULTS

Compared with NS, the maximum lifting height was achieved with less isopentane (2% NS volume). Longer persistency and faster operation for submucosal dissection were also recorded for isopentane during the in vitro study. Aerification resulted in vacuolization of submucosal connective tissue, which facilitates EMR and postoperative recovery. The same results were confirmed in the rat model. With the same dosage, isopentane produced better mucosal elevation and larger range than NS. According to the histologic examination, no tissue injury was observed with isopentane application.

CONCLUSIONS

As a submucosal injection agent, the feasibility, efficacy, and safety of isopentane has been demonstrated. Thermo-sensitive aerification may be a promising approach to facilitate ESD.

Endoscopic shielding technique with a newly developed hydrogel to prevent thermal injury in two experimental models

BACKGROUND AND AIM

A newly developed hydrogel, applied through the endoscope as an endoscopic shielding technique (EndoSTech), is aimed to prevent deep thermal injury and to accelerate the healing process of colonic induced ulcers after therapeutic endoscopy.

METHODS

Lesions were performed in rats (n = 24) and pigs (n = 8). Rats were randomized to receive EndoSTech (eight rats each) with: saline (control), hyaluronic acid and product. In pigs, three ulcer sites were produced in each pig: endoscopic mucosal resection (EMR)-ulcer with prior saline injection (A; EMR-saline), EMR-saline plus EndoSTech with product (B; EMR-saline-P), and EMR with prior injection of product plus EndoSTech-P (C; EMR-P-P). At the end of the 14-day study, the same lesions were performed again in healthy mucosa to assess acute injury. Animals were sacrificed after 7 (rats) and 14 (pigs) days. Ulcers were macroscopically and histopathologically evaluated. Thermal injury (necrosis) was assessed with a 1-4 scale.

RESULTS

In rats, treatment with product improved mucosal healing comparing with saline and hyaluronic acid (70% vs 30.3% and 47.2%; P = 0.003), avoiding mortality (0% vs 50% and 25%; P = 0.038), and perforation (0% vs 100% and 33.3%; P = 0.02); respectively. In pigs, submucosal injection of product induced a marked trend towards a less deep thermal injury (C = 2.25-0.46 vs A and B = 2.75-0.46; P = 0.127). Mucosal healing rate was higher with product (B = 90.2-3.9%, C = 91.3-5.5% vs A = 73.1-12.6%; P = 0.002).

CONCLUSIONS

This new hydrogel demonstrates strong healing properties in preclinical models. In addition, submucosal injection of this product is able to avoid high thermal load of the gastrointestinal wall.

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.

Tumescent TAPP: laparoscopic inguinal hernia repair after the preperitoneal tumescent injection of diluted lidocaine and epinephrine saline solution and carbon dioxide gas

PURPOSE

Laparoscopic transabdominal preperitoneal inguinal hernia repair (TAPP) is technically difficult and not infrequently followed by postoperative complications and pain, especially when performed by inexperienced surgeons. To simplify TAPP and reduce postoperative pain, we devised a novel procedure whereby TAPP is carried out after the inguinal preperitoneal infiltration of diluted lidocaine and epinephrine saline solution and carbon dioxide gas (tumescent TAPP). This report introduces the concept of tumescent TAPP and summarizes its operative results.

METHODS

About 120 ml of diluted lidocaine and epinephrine solution and 60 ml of CO₂ gas were infiltrated into the inguinal preperitoneal space through a transabdominal needle before TAPP. Tumescent TAPP was performed for 400 patients (355 men, 45 women; mean age, 63.2 years).

RESULTS

Using tumescent TAPP, we found it easier to confirm the inguinal anatomy and dissect the preperitoneal layer and inguinal floor, with less bleeding. The mean operation time was 101.9 min and there were few perioperative complications and minimal pain.

CONCLUSIONS

Tumescent TAPP makes conventional TAPP easier and safer; however, this procedure should be verified by a comparative study with conventional TAPP.

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.

Solutions for submucosal injection in endoscopic resection: a systematic review and meta-analysis

BACKGROUND AND AIMS

Submucosal injection is standard practice in endoscopic mucosal resection of gastrointestinal lesions. Several solutions are used. Our aim was to systematically review their efficacy and safety.

PATIENTS AND METHODS

We performed a systematic review and meta-analysis using a random effects model of randomized controlled trials (RCTs) from MEDLINE. Studies in animal models were qualitatively assessed for efficacy and safety.

RESULTS

In total, 54 studies were qualitatively assessed. Eleven RCTs were analyzed, two of which were on endoscopic submucosal dissection (ESD). The quantitative synthesis included nine RCTs on endoscopic mucosal resection (EMR), comprising 792 subjects and 793 lesions. Mean lesion size was 20.9 mm (range 8.5 - 46 mm). A total of 209 lesions were randomized to sodium hyaluronate (SH) vs normal saline (NS), 72 to 50 % dextrose (D50) vs NS, 82 to D50 vs SH, 43 to succinylated gelatin, 25 to hydroxyethyl starch and 36 to fibrinogen. In total, 385 were randomized to NS as controls. NS and SH are the best studied solutions and seem to be equally effective in achieving complete resection (OR 1.09; 95 %CI 0.82, 1.45). No solution was proven to be superior in complete resection rate, post-polypectomy bleeding or coagulation syndrome/perforation incidence. Many solutions have been tested in animal studies and most seem more effective for mucosal elevation than NS.

CONCLUSIONS

There are several solutions in clinical use and many more under research, but most are poorly studied. SH seems to be clinically equivalent to NS. There are no significant differences in post-polypectomy complications. Larger RCTs are needed to determine any small differences that may exist between solutions.

A feasibility study of a thermally sensitive elastin-like polypeptide for submucosal injection application in endoscopic resection in 3 animal models

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc by using a submucosal injection solution, but the cost of currently available submucosal injection solutions is not satisfactory. The authors' aim was to evaluate the feasibility and effectiveness of a thermally sensitive elastin-like polypeptide (ELP) used as submucosal injection solution in ESD.

METHODS

We conducted an ex vivo study to determine the optimal concentration of ELPs in rabbits, an in vivo study to evaluate the effectiveness of mucosal elevation in rats, and a large animal study to confirm the feasibility of preclinical application by using conventional clinical procedure in pigs.

RESULTS

ELP (500 μM) was proved to be the optimal injectable submucosal injection solution and elevated mucosa more efficiently than any control. The same concentration of ELP exhibited an equivalent effectiveness of mucosal elevation, the retention of the elevation, and minimal bleeding with sodium hyaluronate. The ESD procedure time with 500 μM ELP in a preclinical study with pigs was significantly shorter than with any other concentration of ELP and normal saline solution.

CONCLUSIONS

Use of ELP as submucosal injection solution was feasible, with higher and longer-lasting elevation and fewer adverse events.

Carbon dioxide-induced inhibition of mechanical activity in gastrointestinal smooth muscle preparations isolated from the guinea-pig

Mechanical responses of smooth muscle elicited by application of CO2-gas bubbled physiological salt solution (CO2-gas solution) were investigated in isolated stomach antrum and colon preparations of the guinea-pig. Circular smooth muscle preparations of both colon and stomach were spontaneously active with periodic generation of phasic contractions. In colonic preparations, the CO2-gas solution produced a biphasic response, with an initial small transient contraction followed by a sustained inhibition of phasic contractions. Removal of the CO2-gas solution allowed a slow recovery of the spontaneous contractions over a period of about 40 min. The recovery developed with a similar time course irrespective of the length of time exposed to CO2-gas solution. The inhibitory responses elicited by CO2-gas solution were not modulated by atropine, Nω-nitro-L-arginine or neostigmine. Atropine-sensitive excitatory responses of smooth muscle elicited by transmural nerve stimulation or exogenously applied acetylcholine were attenuated or abolished in the presence of CO2-gas solution. In stomach preparations, the CO2-gas solution elicited a tri-phasic response, with an initial transient relaxation followed by a transient contraction and then a sustained inhibition of the rhythmic contractions. The peak amplitude of the transient contraction was about 2.5 times larger than the spontaneous phasic contractions. The pH of the CO2-gas solution was reduced to about 6. Application of pH 6 solution again produced a tri-phasic response, as was the case for the CO2-gas solution, however the amplitude of the transient contraction was only about 0.4 times that of the spontaneous contractions. The re-appearance of the abolished phasic contraction was quicker with the pH 6 solution (about 1.8 min) than it was for the CO2-gas solution (about 6 min). The inhibitory responses elicited by the CO2-gas solution could be simulated only partly by the acidified solution, and a possible involvement of additional factors in the inhibition elicited by CO2-gas solution was considered.

What are the latest developments in colorectal endoscopic submucosal dissection?

Endoscopic submucosal dissection (ESD) enables direct submucosal dissection so that even large early-stage gastrointestinal tumors can be resected en bloc. ESD has recently been applied to the colorectum since it was originally developed for use in the stomach. However, colorectal ESD is technically more difficult with an increased risk of perforation compared with gastric ESD. In addition, this procedure is seldom performed in Western countries. Consequently, further technical advances and the availability of a suitable clinical training system are required for the extensive use of colorectal ESD. In this topic highlight, we review the most recent developments in colorectal ESD.

A pilot animal and clinical study of autologous blood solution compared with normal saline for use as an endoscopic submucosal cushion

Normal saline is the most popular agent used during endoscopic submucosal injection. However, endoscopists have never identified an optimal submucosal injection solution, which is not only safe and cost-effective but has a unique lifting ability with endoscopic submucosal cushion and causes less tissue damage. This study aimed to evaluate the effectiveness and microscopic characteristics of a blood solution, including whole blood and plasma solution, as a submucosal cushioning agent, compared with normal saline. Endoscopic submucosal dissection (ESD) procedures in pig stomachs were performed by injecting plasma solution (n=4) and normal saline (n=4). A total of 38 patients with gastrointestinal neoplasms underwent endoscopic musocal resection (EMR) procedures. Of 38 EMRs, 7 used whole blood injection, and 31 of 38 acting as the control group used normal saline. A tissue damage scoring system was developed based on injection-induced hydrops and tears for the evaluation of tissue damage. In animal experiments, the lifting time of the injection with normal saline in the pig colon was shorter than that of the group with plasma solution (18.25±5.44 min vs. 6.5±2.38 min, P=0.007). In animal experiments with ESD procedures in the stomach, the hydrops in the normal saline injection group were more extensive than those in the group with plasma (P=0.011). The degree of tearing in the group with normal saline was observed to be less than that in the group with plasma (P=0.008). In patients with EMR, using the histological scoring method, it was determined that the degree of hydrops in the group with normal saline injection was more extensive than that in the group with whole blood (P<0.001). The effective submucosal tearing in the group with normal saline was less than that in the group with blood (P<0.001). The blood solution, including whole blood and plasma solution, as a novel submucosal injection agent, may outperform normal saline with a unique lifting ability, less pronounced tissue damage and marked effective submucosal blunt dissection.

Current opinions for endoscopic submucosal dissection for colorectal tumors from our experiences: indications, technical aspects and complications

Endoscopic submucosal dissection (ESD) was first applied in the resection of large colorectal tumors 10 years ago. Frequent complications and technical difficulties were serious problems at first, but were gradually improved with experience. Here, we describe the indications, technical aspects and management of complications of ESD for colorectal tumors. In 2009, we introduce the use of small tip insulation-tipped diathermic (IT) knife. Features separating it from the IT knife and IT Knife2 are a smaller ceramic tip and small round disk at the root of the tip. During submucosal dissection, the small tip IT knife could dissect large pieces of tissue intact. This allows us to shorten the procedure time, particularly the submucosal dissection component. A total of 146 ESD for 140 patients were performed between January 2009 and July 2011. En bloc, and en bloc and R0 resection rates were 92.5% and 83.6%, respectively. Median procedural time was 48.5 min for 40.5 mm specimens. Perforation and delayed bleeding occurred in 2.1% and 1.4%, respectively. We successfully performed ESD for colorectal tumors with a shortened procedure time while preserving quality and safety.