"In Vitro" Evaluation of Energy-Based Sealing of Graft Side Branches in Bypass Surgery

INTRODUCTION

Our objective was to compare the in vitro efficacy of electrothermal bipolar [EB] vessel sealing and ultrasonic harmonic scalpel [HS] versus mechanical interruption, with conventional ties or surgical clips (SC), in sealing saphenous vein (SV) collaterals, during its eventual preparation for bypass surgery.

METHODS

Experimental in vitro study on 30 segments of SV. Each fragment included two collaterals at least 2 mm in diameter. One of them was sealed by ligation with 3/0 silk ties (control) and the other one with EB (n = 10), HS (n = 10) or medium-6 mm SC (n = 10). After incorporation in a closed circuit with pulsatile flow, the pressure was progressively increased until causing rupture. Collateral diameter, burst pressure, leak point, and histological study were recorded.

RESULTS

Burst pressure was higher for SC (1320.20 ± 373.847 mmHg) as compared with EB (942.2 ± 344.9 mmHg, p = 0.065), and especially with HS (637.00 ± 320.61 mmHg, p = 0.0001). No statistically significant difference between EB and HS was found, and bursting always happened at supraphysiological pressures. The leak point for HS was always detected in the sealing zone (10/10), while for EB and SC, it occurred in the sealing zone only in 6/10(60%) and 4/10(40%), respectively (p = 0.015).

CONCLUSIONS

Energy delivery devices showed similar efficacy and safety in sealing of SV side branches. Although bursting pressure was lower than with tie ligature or SC, non-inferiority efficacy was shown at the range of physiological pressures in both, EB and HS. Due to their speed and easy handling, they may be useful in the preparation of the venous graft during revascularization surgery. However, remaining questions about healing process, potential spread of tissue damage and sealing durability, will require further analysis.

Experimental and histological evaluation of different clamp technique for pulmonary artery

OBJECTIVES

The double-loop technique has been used in our clinical settings for pulmonary arterioplasty and/or injured artery repair during thoracoscopic anatomical lung resection. We evaluated the pressure resistance capacity and intimal load to determine the effectiveness and safety of the double-loop technique.

METHODS

The double-loop technique, DeBakey clamp, Fogarty clamp, endovascular clips and vessel loop technique were evaluated. During an experimental study, a polyvinyl alcohol main pulmonary artery model, manometer and in-deflation device were used to measure the burst pressure. The maximum clamp pressure was measured using a pressure-measuring film. Each measurement was performed 10 times. During the histological study, we measured the burst pressure and evaluated the intimal damage of the human pulmonary artery associated with the double-loop technique and DeBakey clamp.

RESULTS

The experimental burst pressure (mmHg) and maximum clamp pressure (MPa) between the double-loop technique and DeBakey at the third notch were not significantly different (24.6 ± 2.8 and 21.8 ± 2.8, P = 0.094; 1.54 ± 0.12 and 1.49 ± 0.12, P = 0.954). During the histological study, the burst pressures of the double-loop technique and DeBakey at the third notch were also not significantly different (P = 0.754). Furthermore, the double-loop technique resulted in only intimal deformation in each five samples.

CONCLUSIONS

The double-loop technique is feasible for thoracoscopic anatomical lung resection because it has similar pressure resistance capacity and intimal load as DeBakey at the 3rd notch.

Technological innovation in video-assisted thoracic surgery

The popularity of video-assisted thoracic surgery (VATS) which increased worldwide due to the recent innovations in thoracic surgical technics, equipment, electronic devices that carry light and vision and high definition monitors. Uniportal VATS (UVATS) is disseminated widely, creating a drive to develop new techniques and instruments, including new graspers and special staplers with more angulation capacities. During the history of VATS, the classical 10 mm 0° or 30° rigid rod lens system, has been replaced by new thoracoscopes providing a variable angle technology and allowing 0° and 120° range of vision. Besides, the tip of these novel thoracoscopes can be positioned away from the operating side minimize fencing with other thoracoscopic instruments. The curved-tip stapler technology, and better designed endostaplers helped better dissection, precision of control, more secure staple lines. UVATS also contributed to the development of embryonic natural orifice transluminal endoscopic surgery. Three-dimensional VATS systems facilitated faster and more accurate grasping, suturing, and dissection of the tissues by restoring natural 3D vision and the perception of depth. Another innovation in VATS is the energy-based coagulative and tissue fusion technology which may be an alternative to endostaplers.

Experimental study in pulmonary artery sealing with a vessel-sealing device

Background

The development of vessel-sealing devices will facilitate safety in video-assisted thoracoscopic surgery. Our objective was to evaluate the feasibility and safety of sealing pulmonary arteries with the Enseal tissue-sealing device.

Methods

Pulmonary arteries from beagle dogs (mean body weight 13.1 kg, range 10.5–15.4 kg) were divided into 3 groups according to the in-vivo sealing method used (Enseal, ligation, and proximal ligation plus distal Enseal) and extracted to evaluate the pressure tolerance up to 75 mm Hg at the sealed end. A left lower lobectomy was performed to evaluate chronic-phase durability of the sealed stumps in a survival model. Two or three branches of the pulmonary arteries in each dog were allocated to each of the 3 groups. After the scheduled survival period, the pulmonary arteries were sampled.

Results

Pressure tolerance at the sealed end was evaluated in 91 pulmonary artery sections. All sealed ends showed pressure tolerance >75 mm Hg. A left lower lobectomy was performed in 13 dogs in which 35 pulmonary artery sections had been allocated into the 3 groups. No sealing failure was found, and pathological findings showed healing and persistent hemostasis at all sealed ends of the pulmonary arteries after 2 and 4 weeks of the survival period.

Conclusions

Pulmonary arteries sealed in vivo with the Enseal device showed pressure tolerance >75 mm Hg in the acute phase, and persistent hemostasis after 2 or 4 weeks. Pulmonary artery sealing with the Enseal device is feasible and safe in thoracic surgery settings.

Present and Future Application of Energy Devices in Thoracic Surgery

In the last decade, many energy devices have entered day-to-day practice in thoracic surgery. Some have proven and recognized applications, whereas others still require further trials. Nevertheless, currently used devices continue to be improved on and new applications for current devices will be evaluated. Ultimately, novel applications of energy in thoracic surgery and refinement in technology will hopefully allow for safer and less invasive techniques for patients requiring thoracic surgical procedures. In this article, we review the present and future applications of energy devices in thoracic surgery.

Short- and long-term outcomes of LigaSure versus conventional surgery for curative gastric cancer resection: a matched pair analysis

BACKGROUND

The LigaSure vessel sealing system allows dissection and hemostasis in a safe and quick way, and it has been reported to be an effective tool to shorten operative time and reduce intraoperative blood loss for various surgeries. However, short- and long-term outcomes in comparison with conventional surgery for gastric cancer resection are limited.

METHODS

Between January 2005 and December 2009, 121 patients underwent curative resection for gastric cancer with LigaSure. Perioperative and long-term results were compared with those of 242 matched patients who received curative resection for gastric cancer with the conventional technique. Immediate operation outcomes, operation morbidity, recurrence and survival were compared between groups.

RESULTS

In the LigaSure group compared with the conventional group, operation time was 156 versus 183 min (P < 0.0001), intraoperative blood loss was 181 versus 236 ml (P = 0.042), intraoperative blood transfusion was 68 versus 161 ml (P = 0.014), and hospital stay was 11.9 versus 13.6 days (P = 0.001). There were no differences in operation morbidity, recurrence rates, overall and disease-free survival between the LigaSure and conventional groups.

CONCLUSIONS

LigaSure is associated with shorter operation time and hospital stay, less blood loss and transfusion, and comparable operation morbidity and long-term outcomes in comparison with conventional surgery for curative gastric cancer resection.

Bipolar impedance-controlled sealing of the pulmonary artery with SealSafe G3 electric current: determination of bursting pressures in an ex vivo model

BACKGROUND

In every anatomic lung resection operation, the pulmonary artery itself or its branches must be sealed. This involves either stapling or ligating the vessels. Based on the positive results with the bipolar vessel sealing ≤7 mm in abdominal surgery the present study aimed to evaluate burst pressures of the pulmonary artery after sealing with the sealing instrument SealSafe G3 (Gebrüder Martin & CoKG, Tuttlingen, Germany).

MATERIAL AND METHODS

The whole pulmonary artery above the pulmonary valve was exposed up to the periphery of the left lung in freshly removed pig heart-lung blocks. A pressure-measuring cylinder was then implanted in the prepared vessel on the side at the main trunk of the pulmonary artery to determine the pressure in the vessel. After either ligation or bipolar sealing of the pulmonary artery, the pneumatic burst pressure (millimeters of mercury) was determined in a water bath. Three groups (n = 12 for each seal type) with different vessel diameters were examined: group 1: 0-6 mm, group 2: 7-12 mm, and group 3: >12 mm. In all cases, vessel sealing was performed with a MARSEAL 5 instrument (Gebrüder Martin & Co KG, Tuttlingen, Germany) and the SealSafe G3 current. The mean burst pressures of the individual groups (ligature and bipolar sealing) were compared using two-tailed, nonparametric Mann-Whitney U test. Significance was defined as P < 0.05.

RESULTS

The mean burst pressures in group 1 were measured by 340 ± 13.4 mm Hg with ligature and 205 ± 44.4 mm Hg with bipolar sealing (P < 0.001). In group 2, the mean values obtained were 270 ± 28.2 mm Hg for ligature and 162 ± 36.0 mm Hg for bipolar sealing (P < 0.001). In group 3, the mean burst pressures for bipolar sealing were only 52.1 ± 15.1 mm Hg, whereas those for ligated vessels were 253 ± 46.9 mm Hg (P < 0.001). For this size of vessel the burst pressure was also determined after stapling. The mean value in this case was 230 ± 21.8 mm Hg.

CONCLUSIONS

In all groups, the mean burst pressures after bipolar sealing were significantly lower than those achieved with ligation, but they were sufficient for a save closure of the pulmonary artery with diameters up to 12 mm.

Usefulness of vessel-sealing devices for ≤7 mm diameter vessels: a randomized controlled trial for human thoracoscopic lobectomy in primary lung cancer

OBJECTIVES

Vessel-sealing devices (VSDs) are widely used for various surgical procedures, including thoracoscopic surgery, but very few reports have compared their safety and usefulness with human thoracoscopic lobectomy procedures not employing VSDs.

METHODS

Primary lung cancer patients for whom a thoracoscopic lobectomy involving mediastinal lymph node dissection was planned in our department from April 2011 to March 2013 were recruited for the study. Patients were randomly allocated to a control group (n = 14) or a VSD group (n = 44), which comprised three sub-groups, namely EnSeal (n = 17), LigaSure (n = 15) and Harmonic (n = 12). The control group comprised patients undergoing surgery solely with ligation and conventional electrocautery. EnSeal, LigaSure and Harmonic were chosen because they are the three most popular disposable VSDs used in Japan. In the VSD groups, the proximal side of pulmonary artery stumps (≤7 mm diameter) were ligated and then treated with respective devices. Primary end-points were burst pressure of the pulmonary artery stump (measured using resected specimens), operative time, intraoperative blood loss, instances of endostapler use, intraoperative surgeon stress (assessed by visual analogue scale) and postoperative drainage volume and duration. As a secondary objective, the individual VSD groups were also compared with each other.

RESULTS

The burst pressure of ligation-treated pulmonary artery stumps was higher than that of VSD-treated stumps (P <0.0001). The burst pressure of <5-mm-wide VSD-treated stumps was higher than that of ≥5-mm-wide stumps (P = 0.0421). However, the burst pressure for all groups and all vessel diameters was sufficient to withstand the physiological pulmonary artery pressure. The VSD group demonstrated reduced intraoperative blood loss (P = 0.0241), surgeon stress (P = 0.0002), postoperative drainage volume (P = 0.0358) and shortened postoperative drainage duration (P = 0.0449). Operative time and the instances of endostapler use did not significantly differ. Comparison between each of the VSD groups revealed no significant differences. None of the patients experienced serious perioperative complications or died because of surgery.

CONCLUSION

VSD is simple and safe to use in thoracoscopic lobectomy involving mediastinal lymph node dissection for primary lung cancer. Furthermore, none of the VSDs used in this study presented any observable differences in quality that could lead to clinical problems.

Feasibility of using a vessel sealing system in a human pulmonary lobectomy: a retrospective comparison of this procedure with or without a vessel sealing system

OBJECTIVE

Despite recent advances in video-assisted thoracoscopic lobectomy, some technical limitations still remain. Our current study purpose was to determine if the vessel sealing system (VSS) has utility in this procedure.

METHOD

112 patients who underwent an anatomic pulmonary lobectomy at our institute were evaluated retrospectively. The burst pressure of pulmonary vessels, which was divided into VSS (VSS group; n = 44) or manual ligature (ligature group; n = 53) groups, was measured experimentally in transected lungs. Perioperative clinical data was also retrospectively evaluated in patients treated with (VSS group) or without using VSS (n-VSS group).

RESULTS

Burst pressures achieved adequate strength in both the VSS (600.0 ± 436.8 mmHg) and ligature (1057.4 ± 462.3 mmHg) groups. Compared with the n-VSS group, the VSS group patients showed lower intraoperative blood loss (115.4 ± 181.1 vs. 183.3 ± 159.1 ml), lower chest fluids by 3rd post-operative day (POD) (533.8 ± 264.8 vs. 705.3 ± 339.3 ml) and a shorter period of chest tube duration (4.1 ± 1.2 vs. 5.4 ± 2.4 days). No serious complications or perioperative (30 days) deaths occurred in either group.

CONCLUSION

The VSS device has the advantage in pulmonary lobectomy procedures, especially those involving video-assisted thoracic surgery (VATS).