Randomized controlled study of injury in the canine right colon from simultaneous biopsy and coagulation with different hot biopsy forceps

A novel bipolar electrocautery-enhanced delivery system with a lumen-apposing metal stent for EUS-guided drainage: A porcine study

BACKGROUND

An electrocautery-enhanced delivery system with a lumen-apposing metal stent (LAMS) is available for one-step endoscopic ultrasound-guided transmural drainage (EUS-TD). Bipolar electrosurgery has several potential clinical advantages, including reduced collateral thermal damage, enhanced hemostasis, and no requirement for a return electrode plate. In this study, we compared the technical feasibility and safety of a newly developed bipolar electrocautery-enhanced delivery system with a conventional delivery system for EUS-TD using a LAMS in a porcine model.

METHOD

Ten days before the study, 12 mini pigs underwent common bile duct ligation for EUS-guided gallbladder drainage. Transenteric puncture was performed, followed by placement of a guidewire. In six pigs, a bipolar electrocautery-enhanced delivery system with LAMS (Hot SPAXUS) was inserted over the guidewire and advanced into the gallbladder, without prior dilation of the tract, by applying a bipolar cut current. In the remaining six pigs, a conventional delivery system with LAMS (Cold SPAXUS) was inserted after tract dilatation using a cystotome. The stent was removed after 4 weeks.

RESULTS

In all pigs, the stent was successfully inserted and deployed in the gallbladder without adverse events. The mean procedure time of EUS-TD was significantly lower in the Hot SPAXUS group than that of the Cold SPAXUS group (mean ± standard deviation: 188.7 ± 5.2 vs 449.5 ± 97.5 s, P = .0019). Stent migration was not observed, and all stents were removed successfully.

CONCLUSIONS

Endoscopic ultrasound-guided transmural drainage using a bipolar electrocautery-enhanced LAMS is feasible for reducing the procedure time while maintaining the high success rate and safety of conventional LAMS.

Devices and techniques for endoscopic treatment of residual and fibrotic colorectal polyps (with videos)

BACKGROUND AND AIMS

Residual neoplasia after macroscopically complete EMR of large colon polyps has been reported in 10% to 32% of resections. Often, residual polyps at the site of prior polypectomy are fibrotic and nonlifting, making additional resection challenging.

METHODS

This document reviews devices and methods for the endoscopic treatment of fibrotic and/or residual polyps. In addition, techniques reported to reduce the incidence of residual neoplasia after endoscopic resection are discussed.

RESULTS

Descriptions of technologies and available outcomes data are summarized for argon plasma coagulation ablation, snare-tip coagulation, avulsion techniques, grasp-and-snare technique, EndoRotor endoscopic resection system, endoscopic full-thickness resection device, and salvage endoscopic submucosal dissection.

CONCLUSIONS

Several technologies and techniques discussed in this document may aid in the prevention and/or resection of fibrotic and nonlifting polyps.

Safety of endoscopic procedures with monopolar versus bipolar instruments in an ex vivo porcine model

Background

Monopolar instruments are generally used in colorectal endoscopic mucosal resection (EMR). Bipolar instruments have previously been reported to be as safe as monopolar instruments. We sought to compare the safety of the monopolar and bipolar snare and hemostatic forceps in an animal model.

Methods

We created 5-mm, 10-mm, and 15-mm target lesions on an ex vivo porcine rectum. Two lesions of each size were resected via monopolar polypectomy (M-P), monopolar EMR (M-E), bipolar polypectomy (B-P), and bipolar EMR (B-E). We performed a pathological evaluation of the conditions of perforation and the effects of burning on the tissues. In addition, we burned the muscularis propria covered with submucosal layer using monopolar and bipolar hemostatic forceps and performed pathological evaluations.

Results

Polypectomy and EMR were performed in a total of 24 target lesions. A perforation was found on histology in one case of M-P and one case of M-E after removing target lesions of 15 mm in diameter. There were no perforations during endoscopic resection using the bipolar snare. The thermal denaturation in B-P did not reach the muscularis propria layer regardless of the size of the target lesion. Although thermal damage after using monopolar hemostatic forceps was extensive, thermal denaturation was only seen on the surface of the submucosal layer when bipolar hemostatic forceps were used.

Conclusions

Bipolar instruments cause less damage to the tissue than monopolar instruments. Our results also suggest that bipolar instruments may be safer than monopolar instruments in endoscopic procedures for colorectal lesions.

Complications Following Colonoscopy in a Nationwide Standard Cohort: A Retrospective Case-control Study

Background/Aims

Despite the many reports of colonoscopy complications worldwide, few studies have been performed at the population level in Korea. In this study, a population-based study was performed to evaluate the incidence of post-colonoscopy perforations compared to a control group.

Methods

Between January 2011 and December 2011, data for all cases (age over 45) who underwent a colonoscopy were collected from National Health Insurance Service using a random sampling method. The clinical characteristics and perforation incidence (within 30 days after the colonoscopy) of cases were identified, and cases were then compared with controls who had not undergone a colonoscopy.

Results

Among 1,380,000 subjects, 31,177 cases and 62,354 controls were identified. Perforation occurred in 14 patients (0.04%) in the case group and one patient (<0.01%) in the control group (RR, 28.0; 95% CI 3.7-212.9, p<0.001). Subgroup analysis was followed according to the endoscopic procedure, gender and age. In subgroup analysis, colonoscopy-associated perforations occurred more in the therapeutic procedure (RR, 26; 95% CI 1.46-461.46), male (RR, 50; 95% CI 2.96-844.41), and age of 45-60 years (RR, 30; 95% CI 1.71-525.23).

Conclusions

A colonoscopy procedure is related to an increased risk of perforation at the population level. In addition, the therapeutic procedure, male, and age of 45-60 years appeared to be associated with an increased risk of perforation.

Novel evaluation method for electrosurgical ablation by monopolar hot biopsy forceps for colonoscopy

Aim

This study evaluates tissue injury, which results from electrosurgical ablation, by correlating lesion depth to tissue impedance, and introduces a newly developed real-time feedback control system that can be applied for preventing excessive tissue injury. Although some previous studies had evaluated such tissue injuries in other ways, a specific mechanism is necessary to actually prevent excessive tissue injury.

Materials and methods

Ablation tests were performed by using an impedance bridge circuit and gel block that have been developed in two previous studies. Depth of the ablation site was measured with the use of a laser displacement measurement device. To simplify the programing work, voltage was used, as a substitution of tissue impedance, to evaluate tissue injury.

Results

The depth of the ablation site was found to increase with either increased power setting or ablation duration, and the depth was analyzed to investigate correlation with measured voltage. The real-time feedback control system was developed by achieving communication between LabVIEW and an Arduino microcontroller.

Conclusion

It is concluded that the depth of the ablation site modestly correlates with the measured voltage under specific conditions, and the newly developed system fulfills the goal of the design.

Should hot biopsy forceps be abandoned for polypectomy of diminutive colorectal polyps?

Standardized approach to polypectomy of diminutive colorectal polyps (DCPs) is lacking since cold biopsy forceps have been associated with high levels of recurrence, hot biopsy forceps are considered inadequate and risky and cold snaring is currently under investigation for its efficacy and safety. This has led to confusion and a gap in clinical practice. This article discusses the usefulness and contemporary practical applicability of hot biopsy forceps and provides well-intentioned criticism of the new European guidelines for the treatment of DCPs. Diminutive colorectal polyps are a source of frustration for the endoscopist since their small size is accompanied by a considerable risk of premalignant neoplasia and a small but non-negligible risk of advanced neoplasia and even cancer. Since the proportion of diminutive colorectal polyps is substantial and exceeds that of larger polyps, their effective removal poses a considerable workload and a therapeutic challenge. During the last decade, the introduction of cold snaring to routine endoscopy practice has attempted to overcome the use of prior techniques, such as hot biopsy forceps. It is important to recognize that with the exception of endoscopic methods that are obviously unsafe and inadequate to serve their purpose, all other interventional endoscopic methods are operator-dependent in the sense that specific expertise and training are obligatory for the success of any therapeutic intervention. Since relevant publications on hot biopsy forceps are still in favor of its careful use, as it has not yet demonstrated inferiority compared with newer techniques, it would be prudent for any medical practitioner to evaluate the available tools and judge any new proposed technique based on the evidence before it is adopted.

Standardisation of polypectomy technique

There are several approaches to polypectomy for sessile polyps <20 mm and for pedunculated polyps. Recent evidence is leading towards standardisation of polypectomy technique. Key recent polypectomy developments include: 1. Use of cold snare polypectomy (CSP) for sessile polyps <10 mm; 2. Use of hot snare polypectomy (HSP) following submucosal injection for sessile polyps sized 10-19 mm; 3. Piecemeal cold snare polypectomy (PCSP), with or without prior submucosal injection, for select sessile polyps sized 10-19 mm, where the potential risk for an adverse event is increased (e.g. polyps in the caecum or ascending colon, or patients with increased risk of post-polypectomy bleeding), and where the risk of submucosal invasion is low; 4. Avoidance of hot biopsy forceps (HBF); 5. Limiting the use of cold biopsy forceps (CBF) to the smallest of diminutive polyps, where CSP is not feasible; 6. Mechanical haemostasis prior to polypectomy for large pedunculated polyps with head ≥20 mm or stalk ≥10 mm.

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.

The role of equipment in endoscopic complications

The role of the surrounding equipment in endoscopic complications has not been published widely. However, an adequate understanding of the advantages and disadvantages of such devices might be helpful to avoid unnecessary problems during endoscopy. This is an overview of the basic principles, benefits and possible harms of electrical power units, medical gases and vital sign monitoring equipment. The aim of this review is to summarize current knowledge about the approach to the electrosurgical unit settings; periprocedural precautions, minimizing the risk of interference between endoscopic equipment and other electrical devices; the appropriate selection of instruments regarding the electrosurgical outcome and the role of carbon dioxide, argon plasma coagulation, pulse oximetry and capnography.

Colon polypectomy: a review of routine and advanced techniques

The value of performing comprehensive screening colonoscopy with complete colon polypectomy is widely accepted. Colon cancer is a significant cause of worldwide mortality and prospective studies have proven that colonoscopic polypectomy reduces both the incidence and mortality related to this disease. Over the past few decades the array of instruments and techniques have greatly expanded to assist with the safe endoscopic removal of colon polyps. This article will review the published literature regarding efficacy and safety of standard polypectomy techniques such as snare polypectomy, electrocautery, and endoscopic mucosal resection along with newer techniques such as endoscopic submucosal dissection and combined laparoscopic techniques.

A blinded comparison of the safety and efficacy of hot biopsy forceps electrocauterization and conventional snare polypectomy for diminutive colonic polypectomy in a porcine model

BACKGROUND

Although linked with perforation, serositis, delayed bleeding, and incomplete resection, hot biopsy forceps electrocauterization (HBF) is still widely used for diminutive colonic polypectomy.

OBJECTIVE

To evaluate the safety and efficacy of HBF in comparison with conventional snare polypectomy (CSP).

DESIGN

Randomized, blinded, controlled trial.

SETTING

Academic endoscopy unit.

SUBJECTS

Ten swine.

INTERVENTION

Eighty-two paired polypectomies (41 HBF, 41 CSP) of small, minimally elevated, artificial lesions. Standardized technique using coagulating current at 25 W. HBF: the tissue was avulsed after 1 to 2 seconds of current caused blanching of the artificial pedicle. CSP: the polyp was removed by snare diathermy.

MAIN OUTCOME MEASUREMENTS

Histopathology of resected specimens and polypectomy sites in colectomy specimens at necropsy (lateral mucosal and depth of ulceration, necrosis and inflammation).

RESULTS

Some (21%) of the HBF specimens were ablated and uninterpretable. All CSP specimens yielded interpretable specimens. Mucosal necrosis adjacent to HBF resection sites varied widely, between 1.5 and 9 mm (mean 5.7 mm, standard deviation ± 2). There was visible mucosa under the HBF ulcer in 14% of cases. The depth of necrosis in the colon wall was significantly different between the two techniques, with partial muscularis propria (MP) necrosis in 14 of 41 lesions (34%) with HBF, compared with 1 of 41 (2%) of CSP (P < .001), and full-thickness MP necrosis in 9 of 41 lesions (22%) with HBF, compared with 1 of 41 (2%) of CSP (P = .014). There was full-thickness MP inflammation in 13 of 41 lesions (32%) with HBF compared with 5 of 41 (12%) of CSP (P = .06). Transmural subserosal inflammation was seen in 13 of 41 lesions (32%) with HBF compared with 4 of 41 (10%) of CSP (P = .027). There was no relationship between visible lateral mucosal injury and depth of injury (rs = -0.07).

LIMITATIONS

Animal study.

CONCLUSION

Despite use of the standardized HBF technique, there is a wide range of lateral mucosal and deep thermal injury as well as residual target mucosa. HBF also results in a significantly greater depth of tissue injury, with a high proportion of transmural necrosis. Ensuring minimal blanching of the mucosa during the procedure does not protect from deep injury. In comparison to conventional snare polypectomy, HBF is imprecise, potentially ineffective, and hazardous.

Determination of optimal monopolar coagulation settings for upper GI bleeding in a pig model

BACKGROUND

Monopolar electrocautery has had a limited role in the endoscopic therapy of nonvariceal upper GI bleeding because of the lack of specifically designed endoscopic instruments and limited data on how to use this technology for endoscopic applications.

OBJECTIVE

To determine the optimal power settings and durations of endoscopic monopolar electrocautery for nonvariceal gastric bleeding.

DESIGN

Twelve pigs underwent creation of cautery lesions by using a novel monopolar electrocautery device designed for endoscopic hemostasis control. The efficacy as measured by the depth of cautery and safety of monopolar electrocoagulation were evaluated in acute and survival phases.

INTERVENTIONS

Monopolar electrocautery was applied to the stomach with power settings of 25, 50, and 75 W for durations of 2 to 5 seconds.

MAIN OUTCOME MEASUREMENT

The extent of cautery injury was assessed histologically by a blinded pathologist.

RESULTS

An optimal cautery effect was achieved with 50 W of power and durations of cautery of 2 and 3 seconds. For 25 W, durations of cautery of 4 and 5 seconds resulted in good but often superficial cautery effect. For 75 W, durations of cautery of 2 and 3 seconds resulted in good cautery effect, but with marginal safety. The visual diameter of monopolar cautery lesions correlated with the histological depth of the cautery lesions. No adverse effects were observed.

LIMITATIONS

Study conducted in a nonbleeding pig stomach model; thus, results may not apply to control of GI bleeding in patients.

CONCLUSIONS

Based on a nonbleeding pig model, we suggest that the initial settings for monopolar soft coagulation in clinical use should be 50 W for 2 to 3 seconds.

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.

Bipolar electrocoagulation vs conventional monopolar hot biopsy forceps in the endoscopic treatment of diminutive rectal adenomas

OBJECTIVE

To assess whether a cold biopsy from a diminutive rectal adenoma followed by destruction with bipolar (gold probe) electrocoagulation using large probes and high power setting would be a safe and efficient alternative to conventional monopolar hot biopsy forceps (MHBF).

PATIENTS AND METHODS

Eligible patients were those undergoing colonoscopy, fulfilling the criteria of additional clearing colonoscopy and having at least one suspected rectal adenoma < or = 5 mm. At the time of endoscopy patients were randomized to receive treatment for their diminutive rectal adenomas either with cold biopsy followed by repeated gold probe electrocoagulation (Group A) using a 10 Fr catheter with setting 8 (40 W) for 1 second or with MHBF (Group B). These patients were followed up with a colonoscopy at 2-4 months.

RESULTS

A total number of 24 (15 males, 9 females; mean age 56 years) patients were included in group A and 26 (14 males, 12 females; mean age 58 years) in group B. A total number of 38 and 37 diminutive rectal adenomas was detected in patients of Group A and Group B, respectively. At follow up colonoscopy residual adenoma tissue was found in 2 (5.2%) adenomas of 38 in Group A and in 4 (10.8%) of 37 in Group B (P > 0.3). No complications related to colonoscopy or endoscopic treatments in both groups occurred.

CONCLUSIONS

Our data suggest that the use of cold biopsy followed by bipolar electrocoagulation using large probes and high power setting for destroying diminutive rectal adenoma seems to be equally effective and safe as MHBF.

Monopolar coagulation versus conventional endoscopic treatment for high-risk peptic ulcer bleeding: a prospective, randomized study

BACKGROUND

Severe upper GI hemorrhage from an actively bleeding peptic ulcer is sometimes difficult to treat by conventional endoscopic means, such as multipolar electrocoagulation, heat probe coagulation, and injection therapy. It was hypothesized that monopolar coagulation with a "hot biopsy" forceps may be more effective in such cases.

METHODS

A prospective, randomized trial was performed to assess the safety and short-term efficacy of monopolar coagulation versus conventional treatment (combination heat probe coagulation and injection therapy) in the treatment of patients with various types of actively bleeding or high-risk ulcers.

RESULTS

Primary hemostasis was achieved in 54 of 56 actively bleeding patients in the monopolar coagulation group. In contrast, primary hemostasis was achieved in 33 of 43 patients in the control group (p = 0.003), with 8 of the remaining 10 being treated successfully by crossover monopolar coagulation. During 30-day follow-up, bleeding recurred in 6 patients in the conventional therapy group versus none in the monopolar coagulation group (p = 0.012). Post-endoscopy blood transfusion requirements were lower in the monopolar coagulation group. Mortality and surgery rates were zero in both groups. There was no procedure-related complication.

CONCLUSIONS

This study demonstrated improved primary hemostasis and a reduced short-term rate of recurrent bleeding for patients with actively bleeding and high-risk non-bleeding peptic ulcers treated by monopolar coagulation. The complication rate associated with monopolar coagulation was low.

Efficacy of colonic submucosal saline solution injection for the reduction of iatrogenic thermal injury

BACKGROUND

Submucosal saline solution injection may limit the depth of thermal injury to the gut wall by acting as a heat-sink and by increasing the distance between burn and serosa. The aim of this study was to determine the effect of submucosal saline solution injection on depth of colonic thermal injury produced by commonly used endoscopic thermal modalities.

METHODS

Longitudinal colotomy incisions were made on the antimesenteric colonic border of anesthetized swine. Lesions were made by using a bipolar device (20 W, 2 seconds), heat probe (30 J); monopolar contact with hot biopsy forceps (20 W, 2 seconds), and monopolar noncontact with argon plasma coagulation (45 W, 3 seconds). Ten or more lesions were created with each device. Lesions were made with or without prior submucosal injection of 2 mL of normal saline solution. After 24 hours the lesions were excised for histologic analysis. Injury was assessed in relation to the severity of damage to the deep (longitudinal) muscle layer.

RESULTS

The proportions of control lesions (without submucosal saline solution injection) in which deep injury was evident were as follows: argon plasma coagulation, 86%; hot biopsy forceps, 64%; heat probe, 50%; bipolar device, 18%. Submucosal saline solution injection significantly reduced the proportions of lesions with deep injury for argon plasma coagulation (p = 0.009) and heat probe (p = 0.03), but not hot biopsy forceps or bipolar device (argon plasma coagulation, 86% to 21%; heat probe, 50% to 0%; hot biopsy forceps, 64% to 50%; bipolar device, 18% to 9%).

CONCLUSIONS

At equivalent energy outputs, the bipolar device results in less deep injury than the monopolar or heat probe. Submucosal saline solution injection reduced injury to the muscularis propria caused by both heat probe and argon plasma coagulation, but not hot biopsy forceps. Despite submucosal saline solution injection, caution should be exercised when using prolonged monopolar cautery.

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

BACKGROUND

Argon plasma coagulation has been rapidly accepted for endoscopic obliteration of vascular lesions and superficial tumors. Depth of injury is thought to be limited through preferential discharge of energy to nondesiccated tissue. However, argon plasma coagulation-induced injury has not been well characterized. The aim of this study was to characterize argon plasma coagulation-induced colonic injury by using a porcine model.

METHODS

Laparotomy was performed in 6 female swine and the colon exteriorized with the subjects under general anesthesia. Lesions were made with an argon plasma coagulation probe held perpendicular and 2 mm from the mucosa. Variables studied were as follows: power (45 W, 60 W, and 75 W) and duration (1, 2, or 3 seconds; n = 11 for each power/duration combination). Injury was graded as either superficial or deep, involving the muscularis propria.

RESULTS

Circular muscle layer injury correlated closely with power (p = 0.02), duration (p = 0.001), and total energy delivered (r = 0.977). Longitudinal muscle damage was associated with duration of burn (p = 0.001) and total energy delivered (r = 0.855), but correlated poorly with power (p = 0.40). No perforations occurred. Submucosal injection of saline solution had a protective effect with reductions in circular (90% to 10%, p = 0.002) and longitudinal muscle injury (50% to 0%, p = 0.1).

CONCLUSIONS

Injury to the muscularis propria occurs at recommended settings for argon plasma coagulation. Injury correlates with power setting, duration of burn, and total energy delivery. Protective arcing to nondesiccated tissue does not appear to be significant in vivo. Submucosal injection of saline solution protects against deep injury.

Treatment with argon plasma coagulation reduces recurrence after piecemeal resection of large sessile colonic polyps: a randomized trial and recommendations

BACKGROUND

Recurrence is frequent after piecemeal snare resection of large sessile colorectal polyps. The aim of this study was to evaluate the safety and efficacy of argon plasma coagulation (APC) in preventing recurrence when applied to the edge and base of the polypectomy site after apparently complete piecemeal resection.

METHODS

Patients with large (>1.5 cm) sessile polyps removed by piecemeal snare cautery were placed into 2 groups. The first consisted of patients with polyps believed by the endoscopist to be completely excised. These patients were randomized to either no further therapy (control) or to APC of the rim and any residual mucosal or submucosal tissue in the base of the polypectomy site. The second group comprised patients in whom polyps, as judged by the endoscopist, were incompletely excised by snare polypectomy; APC was routinely applied without randomization to all visible remaining adenomatous tissue. Follow-up colonoscopy was performed within 3 months and 1 year; biopsy specimens were taken routinely from the resection site and further polypectomy was performed as indicated.

RESULTS

There were fewer recurrences after APC in the randomized group (1/10 APC, 7/11 no APC; p = 0.02). In the group with initial incomplete snare polypectomy, recurrence was detected at 3 months in 6 of 13 despite APC. One patient was hospitalized with abdominal pain and minor rectal bleeding but required no intervention. There were no other episodes of significant late bleeding caused by piecemeal polypectomy. One patient was referred for surgery after unsuccessful endoscopic management.

CONCLUSIONS

In patients with apparent complete endoscopic snare resection of large adenomas, postpolypectomy application of APC reduces adenomatous recurrence.

Quantitative analysis of the functionality and efficiency of three surgical dissection techniques: a time-motion analysis

The increasing technological complexity of surgery demands objective evaluation of surgical techniques. In particular, alternatives for laparoscopic ligation, such as monopolar coagulation and the relatively new bipolar scissors combining dissection with coagulation, should be analyzed and compared. This study tests the efficacy of quantitative time-motion analysis in evaluating and comparing the functionality and efficiency of dissection and ligation techniques in a clinical setting. Standard dissection with ligation of vessels, bipolar scissors, and monopolar coagulation were consecutively applied to dissect 4 of the small bowel mesentery of pigs, in random order. All actions performed were recorded and analyzed, using a standard action list. The efficiency of each technique was expressed in mean dissection time and number of actions, and the safety in occurrence of complications and severity of microscopic damage. Time-motion analysis evaluated the efficiency objectively and reproducibly (ICC 0.98). Bipolar scissors were significantly more efficient (time 7 +/- 2 min, actions 129 +/- 33) than the standard technique (28 +/- 6, 771 +/- 185) and monopolar coagulation (14 +/- 5, 368 +/- 32) (p < 0.01). Furthermore, bipolar coagulation needed significantly less recoagulation of an oozing vessel (0.5% of the total dissected vessels) than did monopolar coagulation (10.4%), and the damaged zone was significantly smaller (p < 0.05). Significantly less time was spent waiting or exchanging instruments with bipolar scissors than with the standard technique (p < 0.05). This time-motion analysis objectively compared the efficiency and functionality of three surgical dissection techniques during clinical use. Bipolar scissors were more efficient than were both other techniques, and they coagulated vessels more safely than did monopolar coagulation.

Randomized controlled studies of injection Gold Probes compared with monotherapies for hemostasis of bleeding canine gastric ulcers

BACKGROUND

There is a significant interest in combination therapy using endoscopic epinephrine injection and thermal coagulation for nonvariceal hemostasis. The purpose of the study was to compare the relative effectiveness, ease of use, and safety of new Injection Gold Probes to other hemostasis techniques in three randomized, controlled laboratory studies of bleeding canine gastric ulcers.

METHODS

Fifteen dogs with prehepatic portal hypertension were heparinized and bleeding gastric ulcers were induced with jumbo biopsy forceps. Three different prototypes of Injection Gold Probes were compared with monotherapy (thermal, electrocoagulation, or epinephrine injection alone), control, or combination therapy with separate injector and thermal probes. The treatment times, total number of pulses or injections, volume of epinephrine injected, and ease of applications were recorded. Gastric ulcer size, ulcer healing, and complications were evaluated at 1 and 4 weeks.

RESULTS

All endoscopic treatments were effective for acute hemostasis compared with control. Thermal coagulation alone was the fastest treatment to perform. The performance of the first Injection Gold Probe prototype was restricted by its small-gauge needle. The second and third Injection Gold Probe prototypes had a larger-gauge needle and irrigation channel which made them faster and easier to use than separate injection catheters and thermal probes.

CONCLUSIONS

The advantages of Injection Gold Probes were the ability to irrigate, inject, and coagulate without probe removal. Combination therapy did not increase treatment-related complications compared with monotherapies.

Eletrocirurgia: sistemas mono e bipolar em cirurgia videolaparoscópica

O conhecimento das leis físicas e dos mecanismos de funcionamento da eletrocirurgia são de grande importância para o cirurgião. Lesões por eletrocirurgia em laparoscopia têm sido observadas, e estão associadas ao uso do eletrodo monopolar, com freqüência de 1 a 2 lesões a cada 1000 procedimentos.Com relação ao desenvolvimento de lesão, existem vários fatores que influenciam: densidade da corrente; o tipo de onda e de coagulação usadas, com suas respectivas voltagens; as condições de isolamento dos dispositivos; a ocorrência do fenômeno de capacitância; e os riscos oferecidos pelo uso em pacientes com marcapasso. No sistema bipolar, a densidade de corrente encontrada ao redor de seus eletrodos é bem menor, levando a menos lesões e, ainda, elimina vários dos outros mecanismos lesivos, como a placa de retorno e os citados acima. Vários estudos demonstram, em colecistectomias, apendicectomias, polipectomias e outros, que o índice de complicações com o eletrodo bipolar é significativamente menor.