Mara Szyrach

Prospective controlled animal study on biopsy sampling with new flexible cryoprobes versus forceps: evaluation of biopsy size, histological quality and bleeding risk.

Background: Cryoextraction is a procedure used for the recanalization of obstructed airways caused by visible exophytic endobronchial tumor. Biopsy samples obtained by this technique have been shown to be useful for histological assessment. Objectives: The aim of the present animal study was to systematically evaluate biopsy size, histological quality and bleeding risk after cryobiopsy with new, flexible cryoprobes in comparison with forceps biopsy, serving as the gold standard. Methods: Biopsies were obtained from anesthetized pigs with the flexible bronchoscopy technique, and evaluated histologically with respect to their size and quality. Bleeding frequency, bleeding duration and histological changes in the biopsy bed were also recorded. Results: Cryobiopsies were significantly larger than forceps biopsies. The size of cryobiopsies was dependent on the freezing time. The histological quality of the cryobiopsy specimenswas not impaired by the freezing process, whereas forceps biopsies showed typical crush artifacts. Despite the larger defects left in the tracheobronchial system after cryobiopsy, bleeding frequency and duration were not higher compared to forceps biopsy. Conclusions: Since cryobiopsy sampling is not associated with a higher bleeding risk compared with forceps biopsy, this new biopsy technique offers – in addition to a good specimen quality – a safe and valuable tool with the potential of improving the outcome of diagnostic endoscopy.

Efficiency and safety of bipolar vessel and tissue sealing in visceral surgery.

Abstract Background: The aim of this study was to analyze the efficiency and safety of the bipolar tissue/vessel sealing and cutting device EnSeal™ in comparison to the conventional clamp and ligation technique in visceral surgery. Material and methods: In an acute animal model, a part of the small bowel, a part of the colon and the kidneys were resected either with the conventional clamp and ligation technique or with EnSeal™. Operation time, blood loss and blood parameters as well as the lateral thermal spread were evaluated. Results: Small bowel, colon and kidney resection time with the EnSeal™ device was shorter compared to the conventional clamp and ligation technique (small bowel: EnSeal™: 4.7 ± 1.0 min vs. con: 35.1 ± 2.3 min; colon: EnSeal™: 7.0 ± 1.4 min vs. con: 16.3 ± 1.5 min, kidney: EnSeal™: 5.7 ± 1.3 min vs. con: 16.7 ± 3.7 min, p < 0.05) and blood loss was significantly lower. Blood analysis demonstrated no differences in both groups. The lateral thermal spread was not more than 1 mm with EnSeal™. Conclusion: The bipolar sealing in visceral surgery with EnSeal™ can be performed more efficiently in a shorter time, with significantly less blood loss, minimal thermal damage and without changes of blood parameters, indicating biological safety and integrity.

A novel flexible cryoprobe for EUS-guided pancreatic biopsies

BACKGROUND EUS-guided FNA (EUS-FNA) is an established technique for the cytologic diagnosis of pancreatic disease. Attempts to obtain adequate histologic specimens have yielded variable and mostly insufficient results. OBJECTIVE To evaluate the safety, feasibility, and quality of histologic biopsy specimens obtained by using a new cryobiopsy probe and to compare them with standard EUS-FNA and (laparoscopic) trucut biopsy specimens of pancreatic tissue. DESIGN Animal non-survival study. INTERVENTION Eighty-four pancreatic biopsy specimens (12 per group) were obtained in 4 anesthetized pigs by using one of the following the 18-gauge flexible cryoprobe; a conventional, 19-gauge, EUS-FNA needle; or a rigid, trucut biopsy device (18 gauge). The latter, used in laparoscopic surgery, was considered as the criterion standard for obtaining histology specimens. MAIN OUTCOME MEASUREMENTS Specimens were evaluated for artifacts and specimen quality by a blinded pathologist who used a 7-point Likert scale to assess histologic adequacy. Biopsy size and bleeding time after biopsy also were recorded. RESULTS The new cryoprobe was equivalent to the rigid, trucut needle and superior (P < .001) to the conventional 19-gauge FNA needles with respect to artifacts, quality of the specimen, biopsy specimen size, and bleeding. LIMITATIONS Animal model. CONCLUSION EUS-guided cryobiopsy was associated with better specimen quality for histologic analysis and a shorter bleeding time compared with a conventional 19-gauge FNA needle in the animal model. It is a promising new technique for histologic examination of pancreatic tissue.

Evaluation of the novel bipolar vessel sealing and cutting device BiCision® in a porcine model.

Abstract Background: Energy-based technologies for tissue sealing and cutting are increasingly supplementing current standards used for haemostasis and dissection during laparoscopic surgery. For their safe and efficacious use in clinical practice, these instruments have to guarantee sufficient burst resistance and low thermal damage to adjacent tissue in combination with good cutting characteristics. Material and methods: The novel laparoscopic, bipolar electrosurgical sealing and cutting instrument BiCision® was compared to a commercially available laparoscopic device (EnSeal™) on visceral and peripheral arteries and veins in an animal model. Results: For all parameters investigated (burst pressure, cut quality, tissue adhering to the instrument, time needed to seal and cut the vessel and thermal damage), BiCision® was at least as good as EnSeal™. Regarding the burst pressure, BiCision® was superior over EnSeal™ in arteries: 600 mmHg (±478) versus 241 (±269) mmHg, respectively (p < 0.0001*). In veins, almost equivalent burst pressures of 155 ± 134 mmHg (BiCision®) and 173 ± 139 mmHg (EnSeal™) were obtained. Conclusion: BiCision® appeared to be as good as or even superior to EnSeal™. Since EnSeal™ has already been shown to be safe and has been successfully used in clinical practice, BiCision® is assumed to be as efficient and reliable as EnSeal™ under pre-clinical conditions.

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.

Evaluation of the Hemostatic and Coagulation Effects of AUTO CUT and DRY CUT Using a Computer-controlled Cutting System

OBJECTIVES To evaluate a newly developed computer-controlled cutting system for the generation of standardized resections and to systematically compare the hemostatic properties and tissue effect of 2 cutting modes, namely, AUTO CUT and DRY CUT used in urologic procedures. METHODS An isolated perfused kidney model was used to assess blood loss and coagulation depth after resection of tissue specimens of standardized geometry, size, and cutting velocity with a resection loop. Three different effect settings (E1, E3, and E6; 200 W) of the electrosurgical modes AUTO CUT and DRY CUT were compared. Blood loss was determined semiquantitatively by weighing a swab before and after placing it onto the resection area. The coagulation depth was estimated microscopically on cross sections. RESULTS The computer-controlled cutting system creates resections of standardized geometry and size with a high reproducibility. An effect level-dependent increase in hemostasis and coagulation depth could be demonstrated with the cutting modes DRY CUT and AUTO CUT using this computer-controlled cutting system. The hemostatic effect with DRY CUT is significantly more pronounced than with AUTO CUT (E1, E3: P < .0001, E6: P = .004), and the coagulation is significantly deeper (E1, E3, E6: P < .0001). CONCLUSIONS The computer-controlled cutting system creating reproducible resections in combination with the isolated perfused kidney model offers the possibility to systematically investigate bleeding rate and coagulation depth. The stronger hemostatic properties of the DRY CUT mode are more favorable for urologic interventions requiring a higher hemostatic effect than the AUTO CUT mode.