In vivo characterization of colonic thermal injury caused by argon plasma coagulation

Plasma Device Functions and Tissue Effects in the Female Pelvis-A Systematic Review

Medical use of (non-)thermal plasmas is an emerging field in gynaecology. However, data on plasma energy dispersion remain limited. This systematic review presents an overview of plasma devices, fields of effective application, and impact of use factors and device settings on tissues in the female pelvis, including the uterus, ovaries, cervix, vagina, vulva, colon, omentum, mesenterium, and peritoneum. A search of the literature was performed on 4 January 2023 in the Medline Ovid, Embase, Cochrane, Web of Science, and Google Scholar databases. Devices were classified as plasma-assisted electrosurgery (ES) using electrothermal energy, neutral argon plasma (NAP) using kinetic particle energy, or cold atmospheric plasma (CAP) using non-thermal biochemical reactions. In total, 8958 articles were identified, of which 310 were scanned, and 14 were included due to containing quantitative data on depths or volumes of tissues reached. Plasma-assisted ES devices produce a thermal effects depth of <2.4 mm. In turn, NAP effects remained superficial, <1.0 mm. So far, the depth and uniformity of CAP effects are insufficiently understood. These data are crucial to achieve complete treatment, reduce recurrence, and limit damage to healthy tissues (e.g., prevent perforations or preserve parenchyma). Upcoming and potentially high-gain applications are discussed, and deficits in current evidence are identified.

ArgoCap - feasibility and safety of a novel over-the-scope device to facilitate endoscopic APC treatment

INTRODUCTION

Argon plasma coagulation (APC) is an electrosurgical procedure used, among other indications, for treatment of dysplastic Barrett's mucosa. Homogeneous and safe application can be compromised by varying distances and suboptimal angle of the probe to the tissue. In this study, we present ArgoCap, a novel endoscopic device developed to facilitate endoluminal APC treatment. Objectives of this preclinical study were to assess feasibility and safety and to determine suitable APC settings.

MATERIAL AND METHODS

One-hundred and thirty-two APC treatments of predefined areas using various APC settings were performed ex vivo in the opened porcine esophagus. Depth of thermal injury was assessed histologically. Feasibility of APC treatment in different locations was examined in 20 explanted porcine esophagi and in first in vivo porcine applications.

RESULTS

APC treatment in all quadrants of the esophagus was feasible. Histologically, thermal effects involving the whole thickness of the mucosa were visible with all settings. APC with pulsed mode resulted in deep thermal damage with all power settings. No lesions of the muscular layer occurred using precise (E8, E9) and forced (10 W, 20 W) mode.

CONCLUSIONS

Esophageal APC using ArgoCap is feasible and safe. The device has the potential to improve APC treatment of larger mucosal areas.

Successful argon plasma coagulation treatment for self-expandable metal stent obstruction in colorectal cancer

Self-expandable metal stents (SEMS) have often been used to treat malignant colorectal obstruction. But SEMS obstruction occurs due to the ingrowth of colorectal cancer. We report a case in which treatment with argon plasma coagulation (APC) was effective for SEMS obstruction. An 89-year-old man was admitted to our hospital for obstructive colorectal cancer. A SEMS was inserted and it improved malignant colorectal obstruction. Computed tomography scans demonstrated liver and lung metastases. His clinical cancer staging was IVb and he wished to receive palliative care. Two months later, SEMS obstruction occurred due to ingrowth of colorectal cancer. Treatment other than stent-in-stent SEMS insertion was considered because SEMS obstruction occurred in a short period of time. APC treatment was chosen and it improved the obstruction. The duration of stent patency was 62 days. APC is an option but it needs further studies to assess the safety of APC.

Histopathological effects of electrosurgical interventions in an in vivo porcine model of colonic endoscopic mucosal resection

OBJECTIVE

Endoscopic mucosal resection (EMR) in the colon has been widely adopted, but there is limited data on the histopathological effects of the differing electrosurgical currents (ESCs) used. We used an in vivo porcine model to compare the tissue effects of ESCs for snare resection and adjuvant margin ablation techniques.

DESIGN

Standardised EMR was performed by a single endoscopist in 12 pigs. Two intersecting 15 mm snare resections were performed. Resections were randomised 1:1 using either a microprocessor-controlled current (MCC) or low-power coagulating current (LPCC). The lateral margins of each defect were treated with either argon plasma coagulation (APC) or snare tip soft coagulation (STSC). Colons were surgically removed at 72 hours. Two specialist pathologists blinded to the intervention assessed the specimens.

RESULTS

88 defects were analysed (median 7 per pig, median defect size 29×17 mm). For snare ESC effects, 156 tissue sections were assessed. LPCC was comparable to MCC for deep involvement of the colon wall. For margin ablation, 172 tissue sections were assessed. APC was comparable to STSC for deep involvement of the colon wall. Islands of preserved mucosa at the coagulated margin were more likely with APC compared with STSC (16% vs 5%, p=0.010).

CONCLUSION

For snare resection, MCC and LPCC did not produce significantly different tissue effects. The submucosal injectate may protect the underlying tissue, and technique may more strongly dictate the depth and extent of final injury. For margin ablation, APC was less uniform and complete compared with STSC.

Rebleeding after hemoclip versus argon plasma coagulation for gastrointestinal angiodysplasias: a retrospective multicenter study

BACKGROUND

Hemoclips are utilized for treating bleeding gastrointestinal angiodysplastic lesions (GIADs); however, the supporting evidence is limited.

AIMS

Our aim is to evaluate the efficacy of hemoclips in preventing bleeding secondary to GIADs compared to argon plasma coagulation (APC).

METHODS

This retrospective study included patients with bleeding gastric, small bowel or colonic GIADs that were endoscopically treated between January 2009 and November 2016. Patients that received hemoclips as monotherapy or in combination were compared to a randomly selected similar number of patients treated with APC.

RESULTS

We included 157 patients that underwent APC and 141 who received hemoclips. During a median follow-up of 17 months, those with hemoclips had a 32.6% rebleeding vs. 46.5% in the APC group (P = 0.017). On multivariate regression analysis, use of hemoclips was not a significant predictor of rebleeding when compared to APC; hemoclips monotherapy (HR, 0.92; 95% CI, 0.54-1.59) and hemoclips combination (HR, 0.65; 95% CI, 0.41-1.01). When the multivariate analysis was restricted to subjects that resumed antithrombotics after endoscopy, rebleeding risk was lower when hemoclips were used in combination (HR, 0.46; 95% CI, 0.25-0.84) compared to APC. We noted a similar effect in the antithrombotic subgroup even after propensity score matching (HR, 0.51; 95% CI, 0.27-0.95).

CONCLUSION

Treatment modality was not a significant predictor of rebleeding when studied for the entire population. However, the risk of rebleeding was lower with hemoclips combination therapy compared to APC in patients that resumed antithrombotic therapy, suggesting a potential role for a combined approach in this subgroup of patients.

Spray coagulation with snare-tip versus argon plasma coagulation: An ex vivo study evaluating tissue effects

Background and study aims  Argon plasma coagulation (APC) is an effective and safe modality for many gastrointestinal conditions requiring hemostasis and/or ablation. However, it can be quite costly. A potentially more cost-effective alternative is snare-tip spray coagulation (SC). This study aimed to determine whether SC would be a safe and effective alternative to APC using an ex-vivo model. Methods  Using two resected porcine stomach, 36 randomized gastric areas were ablated for 2 seconds with either APC at 1.0 L/min 20 W (APC20) and 1.4 L/min 40 W (APC40) or SC with Effect 2 60 W (SC60) and 80 W (SC80) from 3 mm. Extent of tissue injury was then analyzed histopathologically. Results  The mean coagulation depth was 790 ± 159 µm and 825 ± 467 µm for SC60 (n = 9) and SC80 (n = 8), respectively. This was compared to 539 ± 151 µm for APC20 (n = 8) and 779 ± 267 µm for APC40 (n = 9). Mean difference (MD) in coagulation depth between SC60 and APC40 was 12 µm (95 % confidence interval [CI], -191 to 214 µm; P  = 0.91) and was 47 µm (95 %CI, -162 to 255 µm; P  = 0.81) between SC80 and APC40. There was a greater depth of injury with APC40 (MD, 240 µm; 95 %CI, 62 to 418 µm; P  = 0.04) and with SC60 (MD, 252 µm; 95 %CI, 141 to 362 µm; P  = 0.004) when compared to APC20. Mean cross-sectional area of coagulation was 2.39 ± 0.852 mm² for SC60 and 2.54 ± 1.83 mm² for SC80 compared to 1.22 ± 0.569 mm² for APC20 and 1.99 ± 0.769 mm² for APC40. Seventy-eight percent reached the muscularis mucosa (MM) and 11 % the submucosa in the SC60 group compared to 50 % and 38 % in SC80 and 56 % and 11 % in APC40, respectively. Thirty-eight percent of APC20 specimens reached the MM. The muscularis propria was unaffected. Conclusions  This small ex-vivo study suggests that SC60 and SC80 may be safe alternatives to APC40 with comparable coagulation depths and area effects.

Safety and efficacy of band ligation and auto-amputation as adjunct to EMR of colonic large laterally spreading tumors, and polyps not amenable to routine polypectomy

Introduction:

The safety and efficacy of colonic band ligation and auto-amputation (1) as adjunct to endoscopic mucosal resection of large laterally spreading tumors and (2) for polyps not amenable to routine polypectomy due to polyp burden or difficult location remain unknown.

Methods:

An institutional review board–approved retrospective single-institution study was undertaken of patients undergoing colonic band ligation and auto-amputation from 2014 to date. Patients with indications of ‘endoscopic mucosal resection for laterally spreading tumors’ and ‘polyp not amenable to snare polypectomy’ were included in the study. Data were collected on patient demographics, colonoscopy details (laterally spreading tumors/polyp characteristics, therapies applied, complications), pathology results, and follow-up (polyp eradication based on endoscopic appearance and biopsy results).

Results:

Patients undergoing endoscopic mucosal resection for laterally spreading tumors: Thirty-two patients (31 males, aged 68 ± 9.17 years) underwent endoscopic mucosal resection-band ligation and auto-amputation of 34 laterally spreading tumors (40 ± 10.9 mm). A median of 2 ± 1.09 bands were placed. Follow-up colonoscopy and biopsy results confirmed complete eradication in 21 laterally spreading tumors (70%). Nine (30%) laterally spreading tumors required additional endoscopic therapy to achieve complete eradication. Four (13%) patients underwent surgery for cancer, and two of them had resection specimens negative for cancer or residual adenoma. One patient suffered post-polypectomy syndrome. Patients undergoing band ligation and auto-amputation for polyps not amenable to snare polypectomy: Seven patients underwent band ligation and auto-amputation due to serrated polyposis syndrome (one patient) and innumerable polyps, or polyps in difficult locations (extension into diverticula: two patients; terminal ileum: two patients; appendiceal orifice: one patient; anal canal: one patient). The patient with serrated polyposis syndrome achieved dramatic decrease in polyp burden, but not eradication. Follow-up in five of the six remaining patients documented polyp eradication. The patient with serrated polyposis syndrome suffered from rectal pain and tenesmus following placement of 18 bands.

Conclusions:

Band ligation and auto-amputation in the colon may be a safe and effective adjunct to current endoscopic mucosal resection and polypectomy methods and warrants further study.

Plain Language Summary

Colonoscopy with rubber band placement to aid in complete removal of large polyps and polyps in technically challenging locations

Colonoscopy is a commonly performed procedure for the early detection of colon and rectal cancer, and prevention through polyp removal.During colonoscopy, sometimes situations are encountered making polyp removal difficult. These can include the presence of larger polyps or the location of a polyp in an area that makes removal technically challenging or high risk.A particularly challenging situation arises when after extensive effort there is still polyp tissue remaining that cannot be removed using routine techniques. We are interested in exploring a technique which involves the placement of a rubber band after sucking a small area of the colon lining into a cap loaded onto the tip of the colonoscope. With time the rubber band strangulates the tissue and falls off along with captured tissue and passes out of the colon naturally.To assess the effectives of this technique we studied patients that have undergone this procedure at our GI unit. We identified 32 patients with 34 large polyps between 4cm to 6cm that we placed rubber bands on polyp tissue after we were unable to completely remove the polyp. On their follow up colonoscopy, complete polyp removal was successful in 21 polyps. We were also able to achieve complete polyp removal in 9 of the remaining large polyps after additional treatment. Four patients underwent surgery because cancer was found in analysis of polyp tissue.In 5 of 6 patients with polyps in difficult locations (e.g. partly within the lumen of the appendix), placement of a rubber band led to complete removal of polyp tissue.Two patients in our study population had mild adverse events that were managed with simple measures.We believe our results show promise for our described technique and this technique should be tested in larger studies.

Dose response for argon plasma coagulation in the treatment of weight regain after Roux-en-Y gastric bypass

BACKGROUND AND AIMS

Argon plasma coagulation (APC) of gastrojejunal anastomosis (GJA) is effective in treating weight regain after Roux-en-Y gastric bypass (RYGB). This study aims to compare the efficacy of different APC settings for treating weight regain.

METHODS

This was a single-center retrospective study of patients who had undergone RYGB and then underwent APC from 2014 to 2018 for weight regain. Patients receiving only low-dose APC (45-55 W) or high-dose APC (70-80 W) were compared. The primary outcome was the difference in percentage total weight loss (% TWL) between the groups at 6 and 12 months after the last treatment. Secondary outcomes were technical success, adverse events (AEs), and predictors of weight loss at 12 months.

RESULTS

Two hundred seventeen patients met the inclusion criteria and underwent 411 APC sessions. Of these, 116 (53.5%) patients underwent 267 low-dose APC sessions (2.4 ± 1.5 sessions/patient) and 101 (46.5%) patients underwent 144 high-dose APC sessions (1.4 ± 0.7 sessions/patient). Follow-up rates were 82.9% and 75.3% at 6 and 12 months. At 6 months, the low- and high-dose groups experienced 7.3% ± 6.6% and 8.1% ± 7.4% TWL, respectively (P = .41). At 12 months, the low- and high-dose groups experienced 5.1% ± 8.5% and 9.7% ± 10.0% TWL, respectively (P = .008). Technical success was 100%. The overall AE rate was 8.0%; the most common AE was GJA stenosis (4.6%). The GJA stenosis rate was similar for the low- and high-dose groups (3.0% vs 7.6%, P = .06). High-dose APC remained a significant predictor of greater weight loss at 1 year after controlling for confounders.

CONCLUSION

APC is effective at treating weight regain after RYGB, and higher-watt APC was associated with greater weight loss.

Multicenter case series of patients with small-bowel angiodysplasias treated with a small-bowel radiofrequency ablation catheter

Background and Aims

GI angiodysplasia is the most common cause of small-bowel bleeding. Argon plasma coagulation (APC) is preferred for ablation because of its availability, ease of use, and perceived safety, but it has limitations. An instrument capable of repeated use through the enteroscope, which covers more area of intestinal mucosa per treatment with low risk of damage to healthy mucosa, and which improves ablation, is desirable. A series of patients treated with a through-the-scope radiofrequency ablation (RFA) catheter is reported.

Methods

Patients with a previous diagnosis of small-bowel angiodysplasia (SBA) and ongoing bleeding with melena, hematochezia, or iron-deficiency anemia were eligible for treatment. A small-bowel radiofrequency ablation (SBRFA) catheter was passed through the enteroscope instrument channel. The treatment paddle was pushed against the SBA, achieving coaptive coagulation, and the SBA was treated up to 2 times at standard settings of 10 J/cm². The patients' demographics, pretreatment and posttreatment hemoglobin levels, time to recurrence of bleeding, and need for more therapy were recorded. This study was approved by the institutional review boards of the respective institutions.

Results

Twenty consecutive patients were treated from March until October 2018 and followed up until March 2019. There were 6 women (average age 68 years, standard deviation ± 11.1), and 14 men (average age 73 years, standard deviation ± 10.4). All had undergone at least 1 previous EGD and colonoscopy; 14 patients (70%) had SBA on video capsule endoscopy, and 14 patients had undergone previous endoscopic treatment of SBA with APC. A median of 23 treatments were applied (range, 2-99). The median follow-up time was 195 days (range, 30-240 days). Four patients, including 3 with a left ventricular assist device (LVAD), had recurrent bleeding between 45 and 210 days after treatment, and 2 patients received repeated blood transfusions. Three of those patients underwent repeated endoscopies, including a push enteroscopy and an upper endoscopy with no treatment, and a repeated enteroscopy with SBA treated with APC, respectively. One patient with LVAD underwent arterial embolization.

Conclusions

In this case series, bleeding recurred in 20% of patients in a follow-up time of ≤240 days. Notably, 3 of the 4 patients who had recurrent bleeding had an LVAD. These rates compare favorably with reported bleeding recurrence after APC of SBA. More studies on the benefits of SBRFA, which may include reduced risk of recurrent bleeding or prolonging the time to recurrent bleeding, resource utilization, and factors associated with bleeding recurrence are needed.

Electrosurgical and Laser Therapy Tools for the Treatment of Malignant Central Airway Obstructions

Central airway obstruction (CAO) is associated with significant morbidity and increased mortality. Bronchoscopic electrosurgical and laser ablative tools have proven to be safe and effective instruments for the treatment of malignant CAO. Although therapeutic modalities such as electrocautery, argon plasma coagulation, and laser have been used for decades, additional tools including radiofrequency ablation catheters continue to be developed for the treatment of CAO. These modalities are considered safe in the hands of experienced operators, although serious complications can occur. This review describes various electrosurgical and laser therapy tools used for the treatment of malignant CAO along with the specific advantages and disadvantages of each device.

Bleeding in patients who underwent scheduled second-look endoscopy 5 days after endoscopic submucosal dissection for gastric lesions

Background

Bleeding after endoscopic submucosal dissection (ESD) in antithrombotic drug users is still one of the important issues to be solved. We performed scheduled second-look endoscopy (SLE) 5 days after ESD, when the resumption of antithrombotic agents is assumed to have achieved a steady state, rather than on the day after ESD. We investigated bleeding incidence and the status of ulcers.

Methods

A total of 299 lesions in 299 patients subjected to ESD for gastric neoplasms were enrolled. A double dose of proton pump inhibitors was administered after ESD. SLE was planned 5 days after ESD. Post-ESD bleeding occurring before SLE was defined as early phase post-ESD bleeding, whereas bleeding after SLE was defined as later phase post-ESD bleeding. Forrest IIa and IIb ulcers are defined as high-risk ulcers requiring prophylactic hemostasis. We investigated risk factors for post-ESD bleeding, particularly focusing on the use of antithrombotic agents and the presence of high-risk ulcers requiring prophylactic hemostasis during SLE.

Results

Under a double dose of proton pump inhibitors, early phase post-ESD bleeding occurred in 2.3% of non-users (5/218) and 6.2% of users of antithrombotic agents (5/81). High-risk ulcers were found in 19.0% of the cases during scheduled SLE (55/289). Later phase bleeding occurred in 5.5% of cases [2.8% of non-users (6/213) and 13.2% of users of antithrombotic agents (10/76)]. Cox regression analysis revealed that the risk factor for post-ESD bleeding was antithrombotic treatment (HR: 3.56; 95% CI: 1.63–8.02, p = 0.002) alone. Among patients with high-risk ulcers, a statistically significant increase in bleeding was observed in the later phase in patients under antithrombotic therapy, compared to those not receiving any antithrombotic agents (p = 0.001).

Conclusions

Antithrombotic treatment is a risk factor for post-ESD bleeding despite SLE being scheduled 5 days after ESD. Later phase post-ESD bleeding was observed in 13.2% of the patients under antithrombotic treatment even after prophylactic hemostasis for high-risk ulcers.

Trial registration

This study was registered in the UMIN Clinical Trials Registry System (000023306). Retrospectively registered on 23rd July 2016.

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

BACKGROUND

This prospective, randomized, controlled, single-blinded study investigates the peritoneal adhesion formation of HybridAPC (waterjet elevation of the peritoneum with subsequent argon plasma coagulation) versus only waterjet (elevation with the same instrument, but without subsequent argon plasma coagulation) in a rat model (24 female Wistar rats).

MATERIALS AND METHODS

Bilateral lesions were created on the abdominal wall with HybridAPC on one sidewall and waterjet elevation on the other sidewall of the peritoneum in a standard fashion. After 10 days, the rats were euthanized to evaluate the peritoneal trauma sites.

MAIN OUTCOME MEASURE(S)

Adhesion incidence, quantity, and quality were scored 10 days postoperatively and studied histopathologically.

RESULT(S)

Incidence of adhesion formation was 2.3% for HybridAPC; no adhesions occurred for peritoneal elevation with saline (p = 1.00). Histologic evaluation revealed no acute inflammation in both groups. An overall moderate degree of granulation tissue formation and myonecrosis was observed in the HybridAPC group, whereas no chronic inflammation and myonecrosis occurred after elevation without thermal ablation (p < 0.0001).

CONCLUSION(S)

This study investigates the effect of waterjet elevation of the peritoneum with and without subsequent thermal ablation on adhesion formation in a rat model for the first time. Peritoneal waterjet elevation with saline does not provide any risk of adhesion formation. Thermal coagulation with APC after waterjet elevation of the peritoneum creates advantageous peritoneal conditions due to a permanent moist tissue surface and the cooling effect of the injected solution, resulting in no significant difference in adhesion formation compared to peritoneal elevation without thermal ablation. HybridAPC can thus be regarded as a beneficial coagulation method with only minor adhesion formation due to positive tissue effects of the combined waterjet.

A Comparison of Thermal Plasma Energy Versus Argon Beam Coagulator-Induced Intestinal Injury After Vaporization in a Porcine Model

OBJECTIVES

Complete cytoreduction of ovarian cancer often requires excision or ablation of bowel serosa implants. Both argon beam coagulator (ABC) and thermal plasma energy (TPE) (PlasmaJet; PlasmaSurgical, Roswell, Ga) have been used to ablate bowel serosa implants. Our objective was to identify comparable power settings as well as determine the rate of bowel perforation, depth of thermal injury, and extent of inflammatory response with ABC versus TPE in a porcine model.

MATERIALS AND METHODS

Nine pigs underwent vaporization of small bowel and colon serosa according to assigned treatment group (TPE vs ABC) and settings (ABC: 30, 50, and 70 W; TPE: Cut 10U, 20U, and 30U and Coagulation 10U, 20U, and 30U). Animals underwent necropsy with blinded histomorphologic evaluation on days 0, 3, and 10 postprocedure to assess for presence of bowel perforation, depth of thermal injury, and extent of inflammatory response.

RESULTS

At necropsy, bowel perforation was not identified in any animals. Depth of treatment with ABC in the porcine colon was variable and unrelated to power settings whereas TPE was associated with a consistent treatment depth of 1.0 mm regardless of location or power. Treatment with ABC resulted in greater tissue coagulation and desiccation as well as increased rates of mucosal necrosis, especially at higher settings (>50 W). Treatment with TPE primarily resulted in tissue ablation and minimal mucosal necrosis at low settings (Coag 10U-20U). The inflammatory response associated with TPE treatments was interpreted as biologically benign, and less than that observed with the ABC regardless of treatment settings.

CONCLUSIONS

Both ABC and TPE effectively ablate bowel serosa in a porcine model. The TPE seems to result in a more predictable tissue effect with less inflammatory response, especially when used at low power settings such as Coag 10U or 20U. These characteristics are appealing for ablation of bowel serosa implants during ovarian cancer surgery and warrant further investigation.

Effects of argon plasma coagulation on human stomach tissue: An ex vivo study

BACKGROUND AND AIM

Argon plasma coagulation (APC) is a safe alternative treatment for gastrointestinal neoplasms and precancerous lesions. However, the extent of thermal damage after APC is difficult to predict. We investigated the effects of APC on human stomach tissue.

METHODS

Argon plasma coagulation was performed on 10 freshly resected human stomachs that were obtained after total gastrectomy. The effects on tissue were compared across power settings (40, 60, and 80 W), durations (5, 10, 15, 20, and 25 s), and between injection (submucosal injection of normal saline) and control (without injection) groups. Success was defined as complete mucosal necrosis without damaging the muscularis propria.

RESULTS

Without submucosal injection, the incidence of damaging the muscularis propria increased as the power and duration increased. Tissue damage in the injection group was mostly confined to the submucosa, even when using the high-power setting. In the injection group, ablations at 40 W for 20 s, 60 W for 15 s, and 80 W for 15 or 20 s produced success rates ≥80%. In the control group, ablations at 60 W for 10 s, and 80 W for 5, or 10 s produced success rates ≥80%. The optimal energy levels to achieve complete mucosal and submucosal necrosis without damaging the muscularis propria were 800-1600 and 600-800 J in the injection and control groups, respectively.

CONCLUSION

Application of APC produces good results with a low risk of perforation.

Evaluation of argon plasma coagulation in healing of a solitary rectal ulcer in comparison with conventional therapy: a randomised controlled trial

Introduction

Argon plasma coagulation (APC) has been reported to be effective in the treatment of solitary rectal ulcer syndrome (SRUS). However, it has not appeared to be effective in healing ulcers.

Aim

This study aimed at assessing the effectiveness of APC in controlling rectal ulcer-induced bleeding, and at examining the ultimate effect of this approach in healing these lesions.

Material and methods

This randomised, controlled trial was conducted on 99 patients with SRUS. Patients were randomly enrolled into two groups of APC therapy (intervention) and conventional therapy (control). The control group (n = 58) received a high-fibre diet, laxatives, behaviour therapy, and sucralfate enemas, and the intervention group (n = 41) were treated with APC plus conventional therapy; in fact they received directed and focused argon gas in addition to a high-fibre diet and laxatives.

Results

Responses to treatment in the control group and in the APC-receiving group were 29.3% and 75.6%, respectively. The continuation of ulcer healing after 3 months in the control group was 10.3%, and it was 70.7% in the APC-treated group. There was a significant statistical difference between the two groups (p < 0.004), i.e. bleeding was controlled more frequently in the group receiving APC plus conventional therapies than in the group receiving only the conventional therapies. However, the results showed no statistically significant difference between the two groups in terms of pain relief (p < 0.36).

Conclusions

Argon plasma coagulation not only controlled bleeding in patients with SRUS, but also, in comparison with the conventional methods of treating SRUS, led to healing and continuation of healing of rectal ulcers.

The Tissue Effect of Radiofrequency Ablation on Rectal Mucosa

The aim of this study was to examine the depth of radiofrequency ablation on the rectum. Many elderly people have a rectal mucosal prolapse. The procedure combining radiofrequency ablation and plication of the rectal mucosa was reported as an effective means of treatment. However, no pathologic review of the technique has been reported thus far. This study was conducted from January 2012 to August 2013 at the authors' institution. Thirty rectal specimens obtained from 15 patients who underwent stapled transanal rectal resection were coagulated by radiofrequency ablation using TissueLink at power settings of 30 or 50 W and examined histologically. Mucosal epithelia of all specimens was desquamated after radiofrequency ablation. The distance from the mucosal surface to the lamina muscularis mucosae was significantly shorter in ablated specimens than that of normal mucosa and significantly shorter in proportion to coagulation power settings. This study demonstrated that at least mucosal epithelia disappeared histologically after radiofrequency ablation.

Effectiveness of Endoscopic Treatment for Gastrointestinal Neuroendocrine Tumors: A Retrospective Study

Several recent studies have explored efficacy and safety of different endoscopic treatments for gastrointestinal neuroendocrine tumors (GI-NETs). However, there is no definitive consensus regarding the best endoscopic approach for GI-NETs treatment. Therefore, the present study was conducted to investigate the application of various endoscopic techniques for the treatment of GI-NETs according to the previous conclusions and to summarize the optimal endoscopic modalities for GI-NETs. Ninety-eight patients with 100 GI-NETs removed by endoscopic therapies were reviewed. The pathological complete resection rate (PCRR), complication, local recurrence, and factors possibly associated with the pathological complete resection were analyzed. Twenty-two patients were treated by conventional polypectomy (including 6 cold biopsy forceps polypectomy and 16 snare polypectomy with electrocauterization), 41 by endoscopic mucosal resection (EMR), and 35 by endoscopic submucosal dissection (ESD). The PCRRs of conventional polypectomy, EMR, and ESD were 86.4%, 75.6%, and 85.7%, respectively. Sixteen GI-NETs that had a polypoid appearance, with a mean tumor size of 5.2 mm, were removed by snare polypectomy (PCRR 93.8%). The complication rates of conventional polypectomy, EMR, and ESD were 0.0% (0/22), 2.4% (1/41), and 2.9% (1/35), respectively. There were 2 local recurrences after cold biopsy forceps polypectomy treatment and no local recurrences in the EMR and ESD groups (P = 0.049). The results showed that PCRR was only associated with the depth of invasion (P = 0.038). Endoscopic resection of GI-NETs is safe and effective in properly selected patients. For submucosal GI-NETs, ESD was a feasible modality, with a higher PCRR compared with EMR. For ≤5 mm polypoid-like NETs, snare polypectomy with electrocauterization was a simple procedure with a high PCRR.

Argon plasma coagulation in the right and left colon: safety-risk profile of the 60W-1.2 l/min setting

BACKGROUND AND STUDY AIM

The 40W-0.8 l/min setting is widely recommended for argon plasma coagulation (APC) in the right colon. Until March 2012, we used the 60W-1.2 l/min setting for all sites of the colon. By auditing our experience, we assessed the safety-risk profile of the 60W-1.2 l/min setting in the right and left colon.

PATIENTS AND METHODS

All cases treated with APC by a single endoscopist, using the 60W-1.2 l/min setting for all sites of the colon between October 2001 and December 2007 were identified retrospectively and site, type, number of lesions, and complications were recorded. Between January 2008 and March 2012, information was recorded prospectively.

RESULTS

In the retrospective audit, 290 lesions (101 cecum/ascending, 120 sigmoid/descending, 69 transverse) were treated in 241 patient endoscopies. There were no perforations. In the prospective audit, 156 lesions (83 cecum/ascending, 47 sigmoid/descending, 26 transverse) were treated in 132 patient endoscopies. There was 1/83 (1.2%) perforation in the cecum/ascending colon and none in the transverse or sigmoid/descending (n.s.). Combined, the results yield a cecal/ascending perforation rate of 1/153 (0.6%) patient endoscopies, 1/184 (0.5%) lesions treated and overall perforation rate for all sites of the colon of 1/373 (0.3%) patient endoscopies and 1/446 (0.2%) lesions. Post-polypectomy syndrome and delayed bleeding each occurred in 3/373 (0.8%) patient endoscopies and 3/446 (0.7%) lesions. There were no deaths.

CONCLUSION

In the cecum and ascending colon, the APC perforation rate at the 60W-1.2 l/min setting was no higher than in the left colon and is similar to that reported in previously published series. Therefore, it appears safe, provided the precautions we describe are strictly followed.

Review article: gastrointestinal angiodysplasia - pathogenesis, diagnosis and management

BACKGROUND

Angiodysplasia (AD) of the gastrointestinal (GI) tract is an important condition that can cause significant morbidity and -rarely - mortality.

AIM

To provide an up-to-date comprehensive summary of the literature evaluating this disease entity with a particular focus on pathogenesis as well as current and emerging diagnostic and therapeutic modalities. Recommendations for treatment will be made on the basis of the current available evidence and consensus opinion of the authors.

METHODS

A systematic literature search was performed. The search strategy used the keywords 'angiodysplasia' or 'arteriovenous malformation' or 'angioectasia' or 'vascular ectasia' or 'vascular lesions' or 'vascular abnormalities' or 'vascular malformations' in the title or abstract.

RESULTS

Most AD lesions (54-81.9%) are detected in the caecum and ascending colon. They may develop secondary to chronic low-grade intermittent obstruction of submucosal veins coupled with increased vascular endothelial growth factor-dependent proliferation. Endotherapy with argon plasma coagulation resolves bleeding in 85% of patients with colonic AD. In patients who fail (or are not suitable for) other interventions, treatment with thalidomide or octreotide can lead to a clinically meaningful response in 71.4% and 77% of patients respectively.

CONCLUSIONS

Angiodysplasia is a rare, but important, cause of both overt and occult GI bleeding especially in the older patients. Advances in endoscopic imaging and therapeutic techniques have led to improved outcomes in these patients. The choice of treatment should be decided on a patient-by-patient basis. Further research is required to better understand the pathogenesis and identify potential therapeutic targets.

Advances in gastrointestinal endoscopy

Gastrointestinal endoscopy has undergone a remarkable expansion in its capabilities as a result of sophisticated technological advances in recent years. New imaging technologies, novel ablation and resection techniques, cutting-edge endoscope development and creative extraluminal applications have taken gastrointestinal endoscopy to an exciting new level. An update on some of these advances is presented for the physician audience.

Advances in modern enteroscopy therapeutics

Advances in modern enteroscopy have been largely due to endoscope development but also through the improved availability of endoscopic accessories along with improved understanding in their application. Device assisted enteroscopy began with the double balloon system in 2001 and was quickly followed by single balloon enteroscopy and spiral enteroscopy. These tools revolutionised deep small bowel endoscopy and allowed for the delivery of virtually all known therapeutic endoscopy intervention to almost all segments of the small bowel. This review covers the types of interventions in regards to indications, methods and their safety profiles as well as reviewing the various device assisted endoscopes available and their attributes.

Endoscopic management of chronic radiation proctitis

Chronic radiation proctopathy occurs in 5%-20% of patients following pelvic radiotherapy. Although many cases resolve spontaneously, some lead to chronic symptoms including diarrhea, tenesmus, urgency and persistent rectal bleeding with iron deficiency anemia requiring blood transfusions. Treatments for chronic radiation proctitis remain unsatisfactory and the basis of evidence for various therapies is generally insufficient. There are very few controlled or prospective trials, and comparisons between therapies are limited because of different evaluation methods. Medical treatments, including formalin, topical sucralfate, 5-amino salicylic acid enemas, and short chain fatty acids have been used with limited success. Surgical management is associated with high morbidity and mortality. Endoscopic therapy using modalities such as the heater probe, neodymium:yttrium-aluminium-garnet laser, potassium titanyl phosphate laser and bipolar electrocoagulation has been reported to be of some benefit, but with frequent complications. Argon plasma coagulation is touted to be the preferred endoscopic therapy due to its efficacy and safety profile. Newer methods of endoscopic ablation such as radiofrequency ablation and cryotherapy have been recently described which may afford broader areas of treatment per application, with lower rate of complications. This review will focus on endoscopic ablation therapies, including such newer modalities, for chronic radiation proctitis.

Comparison of hemostatic efficacy for argon plasma coagulation and distilled water injection in treating high-risk bleeding ulcers

GOALS AND BACKGROUND

Endoscopic treatment is recommended for initial hemostasis in nonvariceal upper gastrointestinal bleeding. Many endoscopic devices have been demonstrated to be effective in the hemostasis of bleeding ulcers. However, the hemostatic efficacy of argon plasma coagulation (APC) has not been widely investigated.

STUDY

From February 2007 to February 2008, 271 consecutive patients with high-risk bleeding ulcers, characterized by active bleeding, nonbleeding visible vessels and adherent clots, were admitted to our hospital. Among these patients, 135 nonrandomly underwent either APC therapy or distilled water injection. Pantoprazole infusion was conducted during the fasting period after endoscopy and orally for 8 weeks to encourage ulcer healing. Episodes of rebleeding were retreated with endoscopic combination therapy. Patients who did not benefit from retreatment underwent emergency surgery.

RESULTS

In all,135 patients were enrolled, among whom 6 with gastric malignancy, acute severe illness or multiple bleeding sites were excluded. Finally, hemostatic efficacy in 59 patients treated with APC was prospectively compared with 70 patients treated with distilled water injection. The two treatment groups were similar with respect to all baseline characteristics. Initial hemostasis was accomplished in 57 patients treated with APC, and 64 patients with distilled water injection therapy (97% vs. 91%, P=0.29). Bleeding recurred in 6 patients treated with APC, and in 17 patients treated with distilled water injection (11% vs. 27%, P=0.03). No significant differences were observed between the 2 groups in hospital stay, transfusion requirements, surgery and mortality.

CONCLUSIONS

Endoscopic therapy with APC is more effective than distilled water injection for preventing rebleeding in the treatment of high-risk bleeding ulcers.

Adrenaline injection plus argon plasma coagulation versus adrenaline injection plus hemoclips for treating high-risk bleeding peptic ulcers: a prospective, randomized trial

BACKGROUND/OBJECTIVE

Several combination endoscopic therapies are currently in use. The present study aimed to compare argon plasma coagulation (APC) + adrenaline injection (AI) with hemoclips + AI for the treatment of high-risk bleeding peptic ulcers.

METHODS

In a prospective randomized trial, 172 patients with major stigmata of peptic ulcer bleeding were randomly assigned to receive APC + AI (n = 89) or hemoclips + AI (n = 83). In the event of rebleeding, the initial modality was used again. Patients in whom treatment or retreatment was unsuccessful underwent emergency surgery. The primary end point of rebleeding rate and secondary end points of initial and definitive hemostasis need for surgery and mortality were compared between the two groups.

RESULTS

The two groups were similar in all background variables. Definitive hemostasis was achieved in 85 of 89 (95.5%) of the APC + AI and 82 of 83 (98.8%) of the hemoclips + AI group (P = 0.206). The mean volume of adrenaline injected in the two groups was equal (20.7 mL; P = 0.996). There was no significant difference in terms of initial hemostasis (96.6% versus 98.8%; P = 0.337), rate of rebleeding (11.2% versus 4.8%; P = 0.124), need for surgery (4.5% versus 1.2%; P = 0.266) and mortality (2.2% versus 1.2%; P = 0.526). When compared for the combined end point of mortality plus rebleeding and the need for surgery, there was an advantage for the hemoclip group (6% versus 15.7%, P = 0.042).

CONCLUSION

Hemoclips + AI has no superiority over APC + AI in treating patients with high-risk bleeding peptic ulcers. Hemoclips + AI may be superior when a combination of all negative outcomes is considered.

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.

Electrosurgery in gastrointestinal endoscopy: principles to practice

An electrosurgery generator unit is a critical piece of equipment in any therapeutic endoscopy setting. Electrosurgery generators produce high-frequency alternating electric current and differ from electrocautery units in that both cutting and coagulation effects can be achieved. This ability to cut and coagulate at the same time makes electrosurgery an ideal therapeutic tool for gastrointestinal endoscopy. Although education and familiarity with these devices are accepted as the primary avenue to the safest and most effective clinical outcomes, concise information linking the basic properties of electrosurgery directly to clinical practice is not widespread. The following are the aims of this article: (i) to relate the fundamental electrosurgical principles to commonly performed procedures such as snare polypectomy, hot biopsy, sphincterotomy, bipolar hemostasis, and argon plasma coagulation, and (ii) to provide practical suggestions for the use of these devices on the basis of an understanding of electrosurgical principles and the available clinical data.

ENDOSCOPIC MANAGEMENT OF NON-VARICEAL UPPER GASTROINTESTINAL HAEMORRHAGE

Endoscopy plays a central role in the diagnosis and treatment of non-variceal upper gastrointestinal haemorrhage. Advances in endoscopic techniques, supported by an increasing body of high quality data, have rendered endoscopy the first-line diagnostic and therapeutic intervention for the patient presenting with an upper gastrointestinal haemorrhage. However, endoscopic intervention must be considered in the context of the overall management of the bleeding patient, often with significant comorbidities. Although parameters such as hospitalization duration, transfusion requirements and surgery rates have improved with advances in endoscopic therapy, mortality rates remain relatively static. This review addresses the current status of endoscopic intervention for non-variceal upper gastrointestinal haemorrhage. Additionally, an overview of important periprocedural management issues is presented.

In vivo evaluation of argon plasma coagulation in a porcine model

BACKGROUND

Argon plasma coagulation (APC) is a noncontact form of monopolar electrocautery. One purported advantage of APC includes a limit to the depth of injury. It is unclear from previous studies whether the depth of injury is limited to superficial tissue layers with the settings used in clinical practice.

OBJECTIVE

To evaluate the depth and the area of APC-induced injury by using new modes of APC delivery in an in vivo porcine model in the setting of colonoscopy.

DESIGN

Blinded quasi-experiment.

SUBJECTS

Six swine.

INTERVENTION

Colonoscopy with the swine under general anesthesia, with application of APC in 2 different pulsed modes and varying power settings and duration of application.

MAIN OUTCOME MEASUREMENTS

Surface area and depth of colonic mucosal injury. Qualitative histologic analysis of each site of APC application was performed on formalin-fixed specimens after euthanizing the swine.

RESULTS

Muscularis propria injury occurred in 22% of lesions with 10 W, 62% of lesions with 20 W, 86% of lesions with 40 W, and 80% of lesions with 60 W. Muscularis propria injury occurred in 42% of lesions at 1 second, 66% of lesions at 3 seconds, and 69% of lesions at 5 seconds. Depth of injury was significantly correlated with total energy delivered (P = .001, r = 0.75). Surface area was significantly associated with total energy delivered (P < .001, r = 0.81).

LIMITATIONS

This study was performed in distal swine colon rather than human colon. Colon tissue response to APC injury may differ from swine to human colon. The application distance from the APC probe to the colonic tissue may have varied between applications.

CONCLUSIONS

Muscularis propria injury occurs across a broad range of clinically used APC settings. The frequency of deep injury and the surface area of the lesion increases with total energy delivered. The lowest power settings (10-20 W) and the shortest durations have the lowest risk of deep tissue injury.

A novel method of treating colonic angiodysplasia

BACKGROUND

Colonic angiodysplasia is responsible for up to a third of lower-GI bleeding cases. Argon plasma coagulation (APC) is a recognized treatment modality, but active bleeding decreases the ablative efficacy of APC by dissipation of the energy. APC has been associated with colonic perforation.

OBJECTIVES

We propose a novel and safe method for the treatment of colonic angiodysplasia by a submucosal injection of a saline epinephrine solution followed by the application of APC.

PATIENTS

Three patients with a total of 10 colonic angiodysplasias were treated with this injection-APC method.

INTERVENTIONS

Saline adrenaline solution (1:200,000) 2 to 3 mL was injected beneath the angiodysplasia before application of APC. APC 50 W and gas flow 2 L were applied onto the vascular lesion until the sufficient thermal effect was observed.

RESULTS

There were no procedure-related complications.

CONCLUSIONS

This new injection-APC method was safe for the treatment of colonic angiodysplasia. This may be useful in treating right-sided colonic lesions where the risks of perforation are greater than for the rest of the colon.

Comparative experimental study of argon plasma and bipolar coagulation techniques

BACKGROUND

Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique.

METHODS

A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions.

FINDINGS

Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p=0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p=0.032). After twelve days there were no differences in penetration depth (p=0.310) or coagulated area (p=0.222).

CONCLUSION

Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.

Argon plasma coagulation in the management of symptomatic gastrointestinal vascular lesions: experience in 100 consecutive patients with long-term follow-up

BACKGROUND

The long-term efficacy of argon plasma coagulation (APC) in the management of gastrointestinal vascular lesions has not been evaluated in a large and well-defined series. The impact of APC on transfusion requirements and hemoglobin, and technical parameters including complications and number of treatment sessions, is assessed in this series.

METHODS

Patients who underwent APC for bleeding gastrointestinal vascular lesions were identified via interrogation of an established endoscopic database, excluding patients with radiation proctitis, tumors, residual polypectomy tissue and acute ulcer bleeding. Follow-up data were collected via interview with patients and referring doctors, review of medical records, and follow-up blood tests.

RESULTS

One hundred patients were enrolled, males = 46, median age = 74 yr (range: 19-99 yr). Median follow-up time was 16 months (range: 4-47 months). Lesions treated were arteriovenous malformations (n = 74) and gastric antral vascular ectasia (n = 26). Fifty-three patients required transfusion. In this group, median hemoglobin improved from 66 g/L (range: 35-114) to 111 g/L (range: 55-155, p < 0.001). Median transfusion velocity fell from 2 units/month (range: 0.1-6) to 0 units/month (range: 0-4, p < 0.001). Transfusion requirement was abolished in 77%. In non-transfusion-requiring patients, median hemoglobin improved from 105 g/L (range: 58-143) to 123 g/L (range: 79-158, p < 0.001). No complications occurred.

CONCLUSIONS

APC is effective and safe in the management of gastrointestinal vascular lesions.

Advanced polypectomy

Advanced polypectomy includes the approach to large polyps, polyps that are difficult to access, and polyps that require special maneuvers for removal. Sessile polyps are considered difficult to remove, the larger diameters falling into the "very difficult" category, requiring advanced polypectomy techniques. Some pedunculated polyps may require advanced techniques. Most polyps in the colon are sessile, and many of these are located in the right colon, from the hepatic flexure to the cecal caput. Pedunculated polyps, with a pedicle of pulled-out mucosa and submucosa caused by the constant action of peristalsis in the colon's attempt to evacuate the polyp, usually are located in the sigmoid colon.

Long-term outcome of argon plasma coagulation therapy for bleeding caused by chronic radiation proctopathy

BACKGROUND

Radiation-induced proctopathy is a serious complication of radiation therapy for pelvic malignancy.

AIM

To assess the safety and efficacy of argon plasma coagulation in the treatment of haemorrhagic radiation-induced proctopathy.

PATIENTS

Twenty-four patients with rectal bleeding due to radiation-induced proctopathy were prospectively enrolled in the study.

METHODS

Indications for treatment were iron deficiency anaemia (n = 16) and persistent bleeding, despite pharmacotherapy (n = 8). Argon flow and power used were 0.8-1.2 l/min and 40 W, respectively. An interval of at least 4 weeks was allowed between treatment sessions. Haemoglobin level, bleeding severity score, number of admissions and transfusion requirements were recorded after endoscopic coagulation and before 12 and 24 months.

RESULTS

A median of 2.5 therapeutic sessions per patient were performed (range 1-6). All patients reported clinical improvement and/or cessation of rectal bleeding. The mean value of the bleeding severity score decreased from 2.9 to 0.8 (P < 0.01), while average haemoglobin levels increased by a mean of 1.9 mg/dl at the end of the treatments (P < 0.05). During a minimum follow-up of 24 months (range 24-60), rectal bleeding recurred in two cases and was successfully retreated endoscopically. One patient developed a recto-vaginal fistula.

CONCLUSIONS

Argon plasma coagulation appears to be a safe and effective technique for management of rectal bleeding caused by radiation-induced proctopathy.

Argon plasma coagulation of hemorrhagic solitary rectal ulcer syndrome

Solitary ulcer syndrome (SUS) is a rare disorder that may provoke hematochezia. Argon plasma coagulation (APC) is used in a wide range of gastrointestinal bleeding. We experienced APC in a patient with a bleeding gigantic SUS: a 64-year-old woman who developed a SUS at 60. After 3 years, recurrent hematochezia, secondary anemia, and rectal pain occurred. Endoscopy revealed a large rectal bleeding ulcer. Moreover, the pain led the patient to assume analgesics. These conditions stimulated us to treat this ulcer with APC within 4 sessions; each session spaced out at 30-day intervals. The patient experienced and maintained the following benefits: (1) resolution of bleeding and secondary anemia after the first session, (2) reduction of ulcer depth, disappearance of pain and analgesic withdrawal at the end of the cycle, (3) almost complete endoscopic healing of the ulcer after 9 months of follow-up. This experience suggests that APC may represent a therapeutic approach for bleeding SUS even if controlled studies are necessary before recommending it as acceptable treatment.

Argon plasma coagulation (APC) for endo-urological procedures: ex-vivo evaluations of hemostatic properties

OBJECTIVES

Argon plasma coagulation (APC) is an innovative therapeutic modality of non-contact electrocoagulation, which applies high-frequency current via ionized argon plasma. After several years of successful use in open surgery, endoscopic techniques have been established in various surgical fields. The aim of this study was to evaluate the hemostatic properties of this technique in a fluid medium with regard to endourological procedures.

METHODS

Isolated blood-perfused porcine kidneys were used to determine hemostatic efficacy of APC following TURP-like tissue ablation with a conventional loop electrode, compared to standard electrocoagulation with a ball electrode after tissue resection. Blood loss was quantified, specimens were evaluated histologically for coagulation zones.

RESULTS

APC following tissue resection significantly (p<0.001) reduced bleeding compared to conventional contact electrocoagulation subsequent to tissue resection for an ablation volume of 4 cm(3) of perfused kidney tissue (2.1 ml/min vs. 5.6 ml/min). The depths of the coagulation zones were significantly larger (2.4 mm vs. 0.8 mm) and remarkably uniform for the groups treated with APC following tissue resection.

CONCLUSIONS

APC performed in a fluid medium is feasible. APC following conventional TURP-like tissue resection creates significantly better hemostasis compared to standard contact coagulation after tissue resection. These findings justify further investigations to elucidate the value of APC in endourological procedures.