Efficacy and safety of the novel electrosurgical vessel sealing and cutting instrument BiCision®

Vessel-Sealing Capability of Novel Microwave Sealer: Experimental Study in Animal Models

Background. Ultrasonically activated dissectors (UADs) and radiofrequency-based devices have been considered excellent surgical devices because of their reliability and flexibility. Meanwhile, microwave-based devices have demonstrated potential with their unique heating mechanism. This study aims to compare the sealing function of a newly invented forceps-like microwave sealer (MS) with that of currently available UADs. Materials and Methods. MS and 2 examples of UADs (Harmonic Focus+ [HF+] and Sonicision [SNC]) were employed to perform mesenterectomies (in vivo) and sealing sizable vessels (ex vivo). Vessel diameter, seal time, burst pressure (BP), sealing completion, and instrument sticking were recorded. The samples underwent histological investigation for thermal damage evaluation. Results. During mesenterectomies, MS required 3 seconds and 30 W to secure a complete seal. The BP achieved by the MS seal was higher than that of HF+ and SNC on arteries (851 ± 203.7 vs 682.4 ± 287.3, P < .05; vs 833.1 ± 251.2 mmHg, P = .4523, respectively) but was not statistically different on veins (324.9 ± 203.5 vs 460.1 ± 320.3 vs 508.3 ± 350.7 mmHg, P = .215). In all trials, MS caused less sticking but exhibited similar heat-induced alterations to UADs. MS's thermal spread was not statistically more extended than that of UADs on either arteries or veins. Conclusions. MS was capable of not only sealing tiny vessels but also achieving high-pressure endurance on sizable vessels. Its forceful grasping and synchronous heating process helped create solid stumps with an acceptable thermal spread.

Safety and effectiveness of a novel generator algorithm for bipolar vessel sealing: a randomised controlled chronic animal study

BACKGROUND

Electrosurgical vessel sealers are gradually replacing conventional techniques such as ligation and clipping. Algorithms that control electrosurgical units (ESU), known as modes, are important for applications in different surgical disciplines. This chronic porcine animal study aimed to evaluate the safety and effectiveness of the novel thermoSEAL electrosurgical vessel sealing mode (TSM). The BiClamp® mode (BCM) of the renowned VIO® 300 D ESU served as control. BCM has been widely available since 2002 and has since been successfully used in many surgical disciplines. The TSM, for the novel VIO® 3 ESU, was developed to reduce sealing time and/or thermal lateral spread adjacent to the seal while maintaining clinical success rates. The primary aim of this study was to investigate the long-term and intraoperative seal quality of TSM.

METHODS

The BiCision® device was used for vessel sealing with TSM and BCM in ten German Landrace pigs which underwent splenectomy and unilateral nephrectomy during the first intervention of the study. The seals were cut with the BiCision® knife. Ninety-nine arteries, veins and vascular bundles were chronically sealed for 5 or 21 days. Thereafter, during the second and terminal intervention of the study, 97 additional arteries and veins were sealed. The carotid arteries were used for histological evaluation of thermal spread.

RESULTS

After each survival period, no long-term complications occurred with either mode. The intraoperative seal failure rates, i.e. vessel leaking or residual blood flow after the first sealing activation, were 2% with TSM versus 6% with BCM (p = 0.28). The sealing time was significantly shorter with TSM (3.5 ± 0.69 s vs. 7.3 ± 1.3 s, p < 0.0001). The thermal spread and burst pressure of arteries sealed with both modes were similar (p = 0.18 and p = 0.61) and corresponded to the histological evaluation. The measured tissue sticking parameter was rare with both modes (p = 0.33). Tissue charring did not occur. Regarding the cut quality, 97% of the seals were severed in the first and 3% in the second attempt (both with TSM and BCM).

CONCLUSIONS

The novel TSM seals blood vessels twice as fast as the BCM while maintaining excellent tissue effect and clinical success rates.

TRIAL REGISTRATION

Not applicable.

Application of failure mode and effect analysis in total laparoscopic hysterectomy in benign conditions

BACKGROUND

Hysterectomy is the most common major gynecological operation in developed countries. The rate of intraoperative complications related to the laparoscopic approach during hysterectomy is a relevant issue. The failure mode and effect analysis (FMEA) method is a prospective approach, which tries to identify possible errors before they occur.

METHODS

In this study we applied the FMEA method to laparoscopic approach to hysterectomy in order to reduce the theorized risk of intraoperative complications. We selected a team who analyzed and deconstructed the total laparoscopic hysterectomy (TLH) process recording on the FMEA worksheet phases and activities of the entire procedure. Each activity-related failure mode and their potential effects were developed. The team also described actions to eliminate or decrease the likelihood of mistakes.

RESULTS

A numerical value reflecting the risk was assigned to each activity. Five activities were identified as high priority risk, and for each activity actions were then taken to mitigate the identified risk. After introduction of these actions, the risk scores for each activity were recalculated, and we obtained a total risk reduction of 55%.

CONCLUSIONS

It is our opinion that the systematic implementation of the FMEA model can reduce the risk of human error during laparoscopic surgery, improving patient safety.

Thermal effects of a novel electrosurgical device for focused preparation in breast surgery tested in a specified porcine tissue ex vivo breast model using infrared measurement

PURPOSE

This article investigates the qualities and thermal effects of a novel electrosurgical device (PT) which has been designed by ERBE Elektromedizin GmbH, Germany, for the preparation of critical locations such as in skin-sparing or nipple-sparing techniques and compares it to a standard device (SD) in a porcine ex vivo breast model using an heat map generated by infrared thermography.

METHODS

In total, 42 abdominal wall specimens of porcine tissue consisting of the skin and the underlying subcutaneous and muscle layer were alternately dissected using one of the devices and pre-settings. During the preparation with the two devices, the epicutaneous temperature was measured by an infrared camera (VarioCam, Jenoptik, Germany) and the maximum temperature as well as the slope of the temperature rise was analysed.

RESULTS

The use of PT shows significantly lower values for [Formula: see text] compared to SD. This effect was independent from the chosen mode. Using the same instrument in different modes, the use of AutoCut mode showed a significant reduction of [Formula: see text] at all indicated time points (SD: p < 0.0001 and PT: p < 0.0001). In summary, the combination of AutoCut + PT showed the lowest rise in temperature, whereas the combination of DryCut + SD led to the highest rise in temperature. The temperature difference between these two settings was 13.84 °C, which means a possible temperature reduction of 67% can be achieved by the right choice of device and its tailored mode.

CONCLUSIONS

The novel PT shows a significant reduction in epicutaneous temperature and a significant reduction of the slope of temperature rise most probably by a more focused application of energy compared to SD.

An ergonomic field study to evaluate the effects of a rotatable handle piece on muscular stress and fatigue as well as subjective ratings of usability, wrist posture and precision during laparoscopic surgery: an explorative pilot study

PURPOSE

The interface between surgeon and the laparoscopic instrument is an important factor in biomechanical stress that may increase the risk of musculoskeletal complaints in surgeons. This article investigates the effect of a laparoscopic instrument with a rotatable handle piece (rot-HP) on muscular stress and fatigue during routine laparoscopic procedures (LP) as well as usability, wrist posture and working precision.

METHODS

40 LP (subtotal hysterectomies) performed by 11 surgeons were investigated. 20 LP were carried out with the rot-HP and 20 with a fixed (standard) laparoscopic handle piece instrument. Shoulder and arm muscle activity was monitored via surface electromyography (sEMG). The electrical activity (EA) and median power frequency (MPF) were used to determine muscular stress and fatigue. Usability, wrist posture, and working precision between handle piece conditions were assessed by a survey.

RESULTS

Using the rot-HP did not reduce muscular stress. A tendency of muscular fatigue (increasing EA, decreasing MPF) occurred in the upper trapezius, middle deltoid and extensor digitorum muscles; however, no differences were found between handle pieces. Wrist posture was more comfortable using the rot-HP and working precision and usability tended to be preferred using the standard handle piece.

CONCLUSIONS

Although wrist posture seemed to be optimized by the rot-HP, no effect on muscular stress and fatigue was observed in routine LP (< 60 min duration). Optimization of wrist posture may provide positive effects in mid- or long-term procedures. However, sufficient familiarization with the new instrument is crucial since working precision and usability could be impaired.

Prospective analysis of the sealing ability of the ENSEAL® G2 Articulating Tissue Sealer and transector on human mesenteric vessels in colorectal surgery

BACKGROUND

The sealing and transection of mesenteric vessels is a crucial step in minimally invasive colorectal surgery. We examined the sealing quality of the ENSEAL^® G2 Articulating Tissue Sealer in three different articulations in mesenteric vessels.

METHODS

This was a prospective experimental study within a tertiary healthcare center, and 30 patients were recruited. Burst pressures for each specimen were measured as the primary outcome. Ten specimens at each of the three articulations were also histologically assessed for the quality of seal.

RESULTS

We evaluated 54 sets of specimens from 30 patients for bursting pressure, all of which were harvested and sealed in the operating room. No statistical difference was seen in burst pressures from seals recorded at no angulation, half-maximal angulation, or maximal angulation (1604, 1507, 1478 mmHg; p = 0.07). Histological analysis showed no statistical differences in the average vessel diameter (p = 0.57), lateral extent of thermal injury (p = 0.48), degree of vascular sclerosis, or the integrity of seal at the three articulations. No cases of intraoperative or postoperative bleeding were observed in any of the patients. Five (16.7%) of the ENSEAL^® devices developed breaks in the black, heat-shrink, polyethylene covering as a result of repeated articulation and disarticulation. Electrical arcing did not appear to have occurred as a result of the break, although this was not formally examined.

CONCLUSIONS

The maximum sustainable pressure in mesenteric vessels sealed with a bipolar electrothermal device is supraphysiological, and consequently, the device can be safely used at various articulations to seal vessels during colorectal surgery.

In silico evaluation of geometry variations with respect to the thermal spread during coagulation of egg white using bipolar vessel sealing instruments

BACKGROUND

Bipolar vessel sealing is an efficient electrosurgical procedure for the occlusion of blood vessels particularly during minimally invasive surgery. Reliable knowledge of the thermal spread is crucial for a safe application of bipolar vessel sealing instruments when operating close to thermo-sensitive structures, such as nerves. The evolution of the thermal spread over time and space depends on a variety of parameters, such as the biological tissue, the energy applied to the tissue, and the geometry of the vessel sealing instrument. Mathematical modeling has proven useful for the prediction of the thermal spread. It is, thus, a promising tool for the systematic analysis of the influence of geometrical changes on the thermal spread.

RESULTS

We present an experimentally validated in silico study to evaluate the impact of geometry variations on the progression of chicken egg white coagulation and the final shape of coagulated egg white as an approximation of the temporal and spatial evolution of the thermal spread during bipolar vessel sealing. Egg white has similar thermal and electrical properties to human tissue, with the advantage being that the spatial and temporal evolution of the thermal spread can be visually gauged. The simulations were performed using a mathematical model based on the finite element analysis of chicken egg white. The progression of egg white coagulation was predicted for two different peak voltages and various electrode geometries. Starting with two planar electrodes, one electrode was gradually changed to adopt a wedge shape. These changes to the geometry showed a distinct influence on the progression of egg white coagulation in the simulations. The predictions were successfully validated using an experimental setup with two different electrodes representing the extreme geometries.

DISCUSSION

The predicted spatial temperature distributions were experimentally validated for two geometries. Our simulation study shows that the geometry has a pronounced influence on the thermal spread and, thus, is a suitable parameter to reduce thermal damage. The in silico optimization of instrument designs is a suitable tool to accelerate the development of new vessel sealing instruments, with only a few promising designs having to be tested as prototypes.

Comparative analysis between a bipolar vessel sealing and cutting device and the tie and suture technique in thyroidectomy: A randomized clinical trial

BACKGROUND

Advanced bipolar and ultrasonic devices have shown significant reduction in the surgical time of thyroid operations. This randomized, controlled trial assessed if operative time and other relevant outcomes are different for thyroidectomies performed either with a second-generation advanced bipolar device or traditional tie and suture technique.

METHODS

Forty-one patients were randomized into 2 groups (advanced bipolar device and traditional tie and suture). Secondary end points included estimated blood loss, postoperative hemorrhage or hematoma requiring operative reintervention, recurrent laryngeal nerve injury, hypoparathyroidism, pain intensity, number of ligatures, analgesia usage, and loss of signal during recurrent laryngeal nerve monitoring.

RESULTS

Preoperative characteristics were similar between both groups. Mean operative time in the advanced bipolar device group was reduced by 32.5 minutes compared with the traditional tie and suture group (P = .006). Intraoperative blood loss was similar in both groups. Four patients presented postoperative vocal cord dysmotility, 3 in the traditional tie and suture group and 1 in the advanced bipolar device group (P = ns). Two of these 4 patients also had a >50% amplitude decrease during continuous intraoperative neuromonitoring, 1 in each group. Pain intensity, 12 hours after operation, was significantly greater in the traditional tie and suture group (P = .015), even though pain medication requirements during the initial 24 hours after operation were similar between groups (P = .97). There were no cases of postoperative hemorrhage or hematoma requiring reintervention. Postoperative, symptomatic hypocalcemia occurred in 6 patients, 4 in the traditional tie and suture, and 2 in the advanced bipolar device group. One of them developed permanent hypocalcemia.

CONCLUSION

The use of an advanced bipolar device in thyroid operation reduces operative time by >30 minutes, with a similar postoperative outcome profile when compared with the traditional tie and suture technique.

Finite-element-modeling of egg white as a substitute for tissue coagulation during bipolar radiofrequency-induced thermofusion

Radiofrequency-induced thermofusion is a frequently used electrosurgical procedure for the sealing of blood vessels. A disadvantage of vessel sealing instruments is that the generated thermal energy spreads to the surrounding tissue and may irreversibly damage it. This is particularly problematic when operating close to sensitive structures such as nerves. Given their advantages, there is nonetheless a lot of interest in using bipolar vessel sealing for surgical procedures. To select instruments that may be safely used in such cases, it is important to reliably quantify the thermal spread to the surrounding tissue. Mathematical models can help to evaluate the transient behavior, that is the evolution of the thermal spread over time, more precisely. A finite element model allows for a detailed analysis of inhomogeneities in the spatial temperature distribution. As a first step towards a finite model of the bipolar vessel sealing process, a model of the coagulation of chicken egg white is presented here. Egg white has thermal and electrical properties that are very similar to tissue, making it suitable as a substitute for the analysis of the coagulation process. It has the additional advantage, that the spatial and temporal evolution of the thermal spread can be visually gauged. The presented model describes the experimentally observed spatial temperature distribution, the shape of the coagulated egg white, and the formation of hotspots. Furthermore, it is shown that the model can correctly predict the shape of the coagulated egg white in further experiments.

Heat injury to the inferior vena cava by bipolar tissue sealer

BACKGROUND

Although energy devices have brought big advantages to surgery, there are few reports about disadvantages. We conducted an animal experiment to clarify the thermal effect of the bipolar tissue sealing system, Enseal™, to adjacent vessels of the inferior vena cava.

METHODS

We used an experimental miniature pig for the experiment. After laparotomy and mobilization of the intestine, the inferior vena cava was exposed. We activated the device under two different conditions: In the first group, the so-called contact group (Group C), the blade of Enseal™ touched the surface of the IVC directly. In the other group, referred to as non-contact group (Group N), the blade was held about 1 mm away from the IVC. Activation time of the generator was 5, 10, and 15 s, respectively, in both groups.

RESULTS

In Group C, the mean IVC surface temperature was 47.2, 57.6, and 60.4 °C for 5, 10, and 15 s, respectively. The difference between the mean temperature of 5 and 15 s is statistically significant. In Group N, no statistical significance was achieved in all time-settings. The muscular layers of the IVC wall in Group C after 10 s of activation were broken, and cell nuclei were shrunken.

CONCLUSIONS

When Enseal™ is used, contact with the adjacent vessels of the IVC should be avoided at all. It could increase the risk of heat injury to the vessel wall.

A prospective study of in vivo and ex vivo sealing of the human inferior mesenteric artery using an electrothermal bipolar vessel-sealing device

BACKGROUND

Mesenteric vascular ligation is a critical step in minimally invasive colorectal surgery. This study assessed the quality of in vivo and ex vivo sealing of the human inferior mesenteric artery (IMA), as well as the relation of IMA stump and bursting pressure.

PATIENTS AND METHODS

This was a prospective experimental study in a tertiary-care teaching hospital. In total, 25 patients were included in the study. For the main outcome measures, bursting pressures were measured for each specimen. Ten freshly sealed specimens were histologically assessed for seal quality and lateral thermal damage.

RESULTS

We evaluated 54 specimens from 25 patients for bursting pressure, of which 25 were primary sealed vessels (sealed in vivo at surgery) and 29 were secondary sealed vessels (sealed in the laboratory). The mean bursting pressure was 862 mm Hg. The mean diameter was 4 mm (range, 3-5 mm) with a standard deviation of 1 mm. Pearson correlation showed no correlation between diameter and bursting pressure (P=.187) or the length and bursting pressure (P=.247). There was no statistically significant difference in bursting pressures in the four groups of vessels based on length. One calcified vessel had a significantly lower bursting pressure of 89 mm Hg. There was no intraoperative or postoperative bleeding. Ten sealed specimens were sent for histological evaluation, which showed mean lateral thermal damage of 0.57 mm (range, 0-1.75 mm).

CONCLUSIONS

The bursting pressure in IMAs sealed with a bipolar device is significantly higher than physiological pressures; thus, the device can be safely used in sealing the vessel during colorectal surgery. Additionally, the length of the vessel stump does not correlate with the bursting pressures. Care needs to be taken when the vessel is calcified, which can be a potential cause of a weak seal.