Use of an electrothermal bipolar tissue sealing system in lung surgery

Transcription

1 European Journal of Cardio-thoracic Surgery 29 (2006) Use of an electrothermal bipolar tissue sealing system in lung surgery Mario Santini a, *, Giovanni Vicidomini a, Alfonso Baldi b, Giuseppe Gallo a, Paolo Laperuta a, Luigi Busiello a, Maria Pia Di Marino b, Vincenzo Pastore a Abstract a Department of Thoracic Surgery, Second University of Naples, Piazza Miraglia 2, Naples, Italy b Department of Biochemistry and Biophysic F Cedrangolo, Section of Pathology, Second University of Naples, Italy Received 13 September 2005; accepted 1 November 2005 Objective: We evaluated the validity of an electrothermal bipolar tissue sealing system (LigaSure, Valleylab Inc., USA) in lung surgery. Methods: Our study was divided into two phases. Experimental: We performed sutures of pulmonary vessels and bronchi and lung wedge resections by LigaSure in 28 lungs of adult pigs; subsequently, we quantitated the sealing capacity of the system detecting the burst pressure for each anatomical structure. Clinical: LigaSure was used in 36 patients undergoing lung surgery. We performed 23 thoracotomic procedures in 16 patients (19 wedge resections, 2 segmentectomies, and 2 fissure separations), and 20 thoracoscopic procedures (13 wedge resections, 5 bullectomies, and 2 adherence dissections). Results: Experimental: Bronchi and vessels were divided into seven groups (diameter: 1 7 mm); 10 burst pressure measurements for each group were performed. A total of 84 wedge resections were performed; lung specimens were divided into seven groups (weight: g). The percentage of bronchial sutures resistant to the pneumatic critical pressure (60 mmhg) was 100% in the 1- mm and 2-mm groups. No bronchi with 6-mm or 7-mm diameter reached the critical pressure. All pulmonary vessel sutures were resistant to the critical hydrostatic pressure (150 mmhg). The average burst pressure of wedge resection margins was higher than the critical pressure, and the percentage of suture margins resistant to the critical pressure decreased from 95% (0.2-g group) to 68% (1.4-g group). Histology confirmed the sealing of vessels, with a mean depth of thermal injury limited to 1.1 mm. Clinical: In all patients, hemostasis obtained by LigaSure was effective, with minimal perioperative bleeding. The mean operating time was 77.2 min (range: 60 97) for thoracotomies and 60.3 min (range: 46 80) for thoracoscopies. The mean drainage duration was 3.1 days (range: 1 8). Two patients had prolonged air leaks (>7 days). The mean postoperative stay was 7.3 days (range: 5 13) for thoracotomies and 4.6 days (range: 1 6) for thoracoscopies. Conclusions: Use of LigaSure in lung surgery appears feasible and easy. It provides satisfactory hemostasis and air-leak prevention; results are comparable to those of stapling devices, but this system seems to have a better benefit/cost ratio. Larger series are needed to confirm these data. # 2005 Elsevier B.V. All rights reserved. Keywords: Diathermy; Tissue sealing; Hemostasis techniques; Lung surgery 1. Introduction Various diathermy techniques have been proposed to reduce intraoperative blood loss in surgery. In particular, standard bipolar technology is able to coagulate small vessels, with diameters ranging from 1 mm to 3 mm, but it has some disadvantages including sticking, charring, and significant thermal spread [1,2]. A new electrothermal bipolar tissue sealing system (LigaSure, Valleylab Inc., Boulder, CO, USA) has been recently applied in abdominal and pelvic surgery, mostly through laparoscopy [3 8]. Usually, hemostasis is often difficult and unsafe when the laparoscopic approach is performed. The use of this sealing system allows the surgeon to obtain a better vessel sealing with minimal thermal spread to the surrounding tissue. However, the potential role of this technique is still undefined and the experience in the literature is limited. The objectives of our study were to quantitate the healing capacity of this system in the swine s lung model and to evaluate its feasibility and reliability in human lung resection surgery. 2. Materials and methods Our study was divided into two phases Experimental phase Presented at the joint 19th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 13th Annual Meeting of the European Society of Thoracic Surgeons, Barcelona, Spain, September 25 28, * Corresponding author. Tel.: ; fax: address: mario.santini@unina2.it (M. Santini). This study was approved by our Institutional Animal Care Review Board. We evaluated the vessel and airways-sealing capabilities of LigaSure system in 28 lungs of adult pigs, and analyzed the pathological effects and thermal damage of this /$ see front matter # 2005 Elsevier B.V. All rights reserved. doi: /j.ejcts

2 M. Santini et al. / European Journal of Cardio-thoracic Surgery 29 (2006) technology on the surrounding lung tissue. For these purposes, we quantitated the sealing capacity of this sealing system on bronchi, vessels and peripheral lung tissue, detecting the burst pressure for each anatomical structure. The lungs were retrieved after killing the animals, and the bronchial airways and pulmonary vessels were prepared and exposed for the experimental procedures Evaluation of the effects on bronchial airways The LigaSure Standard forceps system was used to ligate bronchi ranging from 1 mm to 7 mm in diameter that were sectioned with scissors distal to the sealing line. Then, a catheter was placed in the bronchial airway proximal to the suture line to be assessed and tied securely in place with a 4-0 Vycril. The catheter was connected to an air flow meter, and the bronchus was placed in a basin filled with saline and inflated with air. The airway pressures were recorded by means of a pressure transducer connected with the insufflation tube. The pressure gradually increased until an air leak was detected through the sealing line. When this occurred, the pressure recorded was considered as the burst pressure Evaluation of the effects on pulmonary vessels The sealing system was used to seal pulmonary arteries and veins ranging from 1 mm to 7 mm in diameter. The vessels were divided with scissors distal to the sealing line. Then, a catheter was inserted in a vessel proximal to the suture line that was flushed with saline. The pressures were measured by a water flow meter and the burst pressure was detected when a fluid leak was noted through the sealing line Evaluation of pneumatic resistance of section margins after lung wedge resection In each of the 28 lungs, three lung wedge resections with increasing sizes were performed. The LigaSure Standard handset was used to seal the base of the lung wedge, and then the resection was performed with scissors distal to the sealing line. The weight of the lung resected varied from 0.2 g to 1.4 g. The lobe that had undergone the wedge resection was placed in a basin filled with saline and the burst pressure was recorded in the same manner described for the bronchi evaluation. All the procedures and measurements on the lungs were performed within 3 h of the animals death. All the bronchi, vessels, and lung wedge resection specimens evaluated were removed and sent to the laboratory for the pathological determination of the thermal effect of the sealing system on the tissues. All the specimens obtained in this phase were evaluated to define the thermal damages on the tissues surrounding the sealing line. The specimens were previously fixed in formalin and, subsequently, processed for paraffin-embedded slides. Finally, they were stained with hematoxylin and eosin, as well as van Gieson s. The depth and the characteristics of thermal injury from the margin were defined Clinical phase From June 2003 to May 2004, we used LigaSure system in 36 patients (25 males, 11 females; mean age: 50.4 years; range: years) undergoing lung surgery. The study was approved by our Institutional Review Board and the enrolled patients signed a full informed consent. All patients were placed in the lateral decubitus position and underwent general anesthesia with single-lung ventilation. We performed a total of 23 procedures by the electrothermal sealing system in 16 patients through thoracotomy (19 wedge resections, 2 segmentectomies, and 2 fissure separations) and 20 procedures in VATS (13 wedge resections, 5 bullectomies, and 2 adherences dissections). The LigaSure Standard forceps handset was used in the thoracotomic procedures. In the VATS procedures, we used the LigaSure Atlas forceps handset that had both vessel-sealing and tissuedividing capabilities. The surgical strategies and techniques were the same as with conventional procedures using standard diathermy coagulation and mechanical staplers. This sealing system eliminated the use of clips and sutures. Various parameters, including presence of air leak at the completion of surgery, operating time, duration of thoracic drainage, and length of postoperative stay, were recorded. The disease was benign in 25 patients and malignant in 11. The histological examination of the specimens was focused on the thermal effects of the sealing system on the lung tissue. Patients characteristics are summarized in Table Results 3.1. Experimental phase Bronchi and vessels were divided into seven groups in accordance with the diameters ranging from 1 mm to 7 mm; 10 burst pressure measurements for each group were performed. A total of 84 wedge resections were performed; the lung specimens were divided into seven groups depending on the weight, ranging from 0.2 g to 1.4 g Bronchi assessment A pneumatic pressure of 60 mmhg, a value threefold higher than the maximal physiologic airways pressure, was Table 1 Patients clinical and surgical data Males 25 Females 11 Age (mean) (years) 50.4 Thoracotomies 16 (23 LigaSure procedures) Wedge resections 19 Segmentectomies 2 Fissure separations 2 VATS 20 Wedge resections 13 Bullectomies 5 Adherences dissections 2 Benign diseases 25 Malignant disease 11 Mean operating time (min) Thoracotomy 77.2 VATS 60.3 Mean thoracic drainage duration (days) 3.1 Prolonged air leaks (>7 days) 2

3 228 M. Santini et al. / European Journal of Cardio-thoracic Surgery 29 (2006) considered as critical pressure. For the three groups of bronchi with diameter ranging from 1 mm to 3 mm, the average burst pressure (104 mmhg, 126 mmhg, and 99 mmhg, respectively) was higher than the critical pressure; for the other groups, ranging from 4 mm to 7 mm, the average burst pressure (56 mmhg, 27 mmhg, 20 mmhg, and 15 mmhg) was lower than the critical pressure. Furthermore, the percentage of LigaSure suture lines resistant to the critical pressure was 100% in the 1-mm and 2-mm groups and it progressively decreased in the groups with a higher diameter. None of the bronchi with 6-mm or 7-mm diameter reached the critical pressure Vessel assessment A hydrostatic pressure of 150 mmhg was considered as critical pressure for the evaluation of the sealing system effects on pulmonary vessels. For all the groups of arteries and veins, the average burst pressure was higher than the critical pressure, and all the vessel suture lines were resistant to a pressure higher than 150 mmhg. The data on resistance of vessels and bronchi to the critical pressure are shown in Fig Wedge resection margins assessment For the evaluation of the effects of sealing system on lung suture margins, a critical pneumatic pressure of 60 mmhg was considered. For all the groups, the average seal burst pressure was higher than the critical pressure and the percentage of suture margins resistant to the critical pressure decreased slightly from 95% (0.2-g group) to 68% (1.4-g group) (Fig. 2). Histological examination on the specimens obtained from the pigs lungs confirmed the sealing of vessel walls without necrotic coagulation of surrounding tissues. The depth of thermal injury at the suture line averaged 1.1 mm (range: ). The same findings were observed for bronchi with diameters ranging from 1 mm to 3 mm. For bronchi with higher sizes, the seal obtained by the sealing system was not satisfactory and the lumen appeared often patent at the level of the ligation line. Figs. 3 and 4 show pathological images of sutures performed by the sealing system. The sealed parts appear securely fused with minimal degeneration of the surrounding tissues. Fig. 2. Resistance of wedge resection margins to the critical pressure (60 mmhg) Clinical phase In all the 32 patients, hemostasis obtained by LigaSure was effective, with minimal perioperative bleeding. There was no mortality. The mean operating time was 77.2 min (range: 60 97) for thoracotomies and 60.3 min (range: 46 80) for thoracoscopies. The mean thoracic drainage duration was 3.1 Fig. 1. Resistance of pigs pulmonary vessels and bronchi sutures to the critical pressure (vessels: 150 mmhg; bronchi: 60 mmhg). Fig. 3. Histopathological image showing a longitudinal section of a porcine pulmonary artery sutured by LigaSure. The collagen and elastin reform to create the seal zone.

4 M. Santini et al. / European Journal of Cardio-thoracic Surgery 29 (2006) Fig. 4. Histopathological image of a wedge resection margin obtained by LigaSure showing an adequate sealing of the pleural surface. The depth of thermal injury in the sealing zone is less than 1.5 mm. days (range: 1 8). Two patients had prolonged air leaks (>7 days) that resolved on its own. No complications, including wound infections, pneumonia, and cardiac dysrhythmia, were seen in the patients. The mean postoperative stay was 7.3 days (range: 5 13) for thoracotomies and 4.6 days (range: 1 6) for thoracoscopies. The histological evaluation of the surgical specimens showed a minimal thermal spread in the tissues surrounding the sealing lines in all the cases. 4. Discussion Bleeding is one of the major complications in surgery. During the past years, several techniques have been used to improve the efficacy and safety of conventional coagulating methods [9,10]. One of the most recent is LigaSure bipolar vessel sealing system that allows local hemostasis by vessel compression and obliteration through the emission of a bipolar energy. This technique is different from the conventional coagulating methods that achieve vessel sealing by tissue carbonization. In fact, the heat generated from the bipolar energy determines the fusion of collagen and elastin in vessel walls and a subsequent tissue reformation with creation of a permanent seal zone. The system detects the thickness of tissue to be coagulated and automatically defines the amount of energy required and the delivering time. An acoustic signal informs the surgeon when the vessel obliteration is complete and its dissection is possible. The seal zone shows a translucent appearance, easy to recognize. Furthermore, this sealing system has a minimal thermal effect on the tissues surrounding the sealing line. The experience with LigaSure system is limited, particularly in thoracic surgery [11 14]. Our study is the first biphasic evaluation of this tissue sealing system, both preclinical on 28 pig lungs and clinical on 32 patients. The use of this coagulation technique in the swine model showed an excellent sealing effect on pulmonary vessels. All the vessel suture lines were resistant to a pressure higher than 150 mmhg, that is above the pressures occurring in physiologic conditions. Thus, this technique can be safely used on vessels 7 mm in diameter, as reported in previous studies based on the use of the system in abdominal and gynecological surgery [3,5,6,8]. The effects of the sealing system on bronchi were not so satisfactory. Our results show that bronchi with diameters up to 2 mm, sutured by LigaSure, resisted to a pressure higher than 60 mmhg that we conventionally considered as a critical pressure. The sealing effect was unpredictable for bronchi with diameters ranging from 3 mm to 5 mm and negligible for those with diameters 6 mm. The good results obtained in smaller bronchi were confirmed by the assessment of suture margins after wedge resection was performed by the system; the sealing capacity of lung tissue was adequate even with large size resections, reaching a weight of 1.4 g. These results indicate that LigaSure is a suitable system for wedge lung resection. They confirm the conclusions of a study by Tirabassi et al. [12] based on the swine survival model; these authors found that sealing of lung tissue by this system was similar to that by endoscopic staplers, and the burst strengths of lung resection margins obtained with both the methods were equal to that of normal lung tissue. As expected, our results suggest that this sealing system is not suitable for the suture of large bronchi, as is required in the case of major lung resections. Our experience with LigaSure in human patients is larger than others reported in literature. The first case report was by Shigemura et al. [11]; afterward, the same research group reported the use of this sealing system in 12 video-assisted thoracoscopic procedures [13]. Albanese et al. [14] successfully used the system for thoracoscopic lobectomy in 14 small children with congenital lung lesions. We applied this coagulation technique either through thoracotomy (16 patients) or video-assisted thoracoscopy (20 patients). In the latter procedures, the LigaSure Atlas forceps that are inserted through a 5-mm porthole were used, which are easy to handle and allow simultaneous coagulation and section of vessels and/or lung tissue. In our study, the use of this sealing technique improved the ablation of pleural adhesions and the hemostasis during lung resections, reducing the use of conventional coagulation methods. We observed no perioperative major bleedings. Two patients who had undergone bullectomy had prolonged air leaks that did not require

5 230 M. Santini et al. / European Journal of Cardio-thoracic Surgery 29 (2006) additional procedures. The values of surgical parameters (operating time, postoperative drainage stay, and postoperative hospitalization) were similar to those for conventional methods. Although the series of patients is limited, we observed no difference in results between the two groups of patients, those treated by open thoracotomy and those by video-assisted thoracoscopy. Compared to staplers, this system allows a better tailoring of nonanatomical lung resection margins, thus saving functional lung tissue and avoids the use of multiple reloadable cartridges, thus reducing the costs of disposable surgical supplies. Another advantage is the minimal thermal spread to the tissues surrounding the sealing line; the pathological evaluation of the specimens obtained in both the phases of our study showed that the maximal depth of thermal damage was less than 2 mm (average value: 1.1 mm). This satisfactory result is better than that obtained by Yim et al. [9], who observed a thermal spread average value of 2.5 mm, using a different method, based on saline enhanced thermal sealing, in 25 patients undergoing lung wedge resection. On the basis of our experience on animals and human patients, we conclude that LigaSure vessel sealing system is an easy and safe technique suitable for lung surgery. Our results confirm the efficacy and safety of the hemostasis obtained by this coagulation system, as previously showed by studies performed in other surgical fields. Furthermore, we believe that this technique could be a valid alternative to staplers for nonanatomical lung resections, also in the thoracoscopic setting. The system seems to allow functional lung tissue preservation and reduction of surgical supplies costs. However, larger series with long-term results and accurate evaluation of cost/benefit ratio are needed to confirm our findings. References [1] Memon MA. Surgical diathermy. Br J Hosp Med 1994;52: [2] Spivak H, Richardson WS, Hunter JG. The use of bipolar cautery, laparosonic coagulating shears, and vascular clips for hemostasis of small and medium-sized vessels. Surg Endosc 1998;12: [3] Kennedy JS, Stranahan PL, Taylar KD. High-burst strength, feedbackcontrolled bipolar vessel sealing. Surg Endosc 1998;12: [4] Romano F, Caprotti R, Franciosi C, De Fina S, Colombo G, Uggeri F. Laparoscopic splenectomy using Ligasure. Preliminary experience. Surg Endosc 2002;16: [5] Shamiyeh A, Schrenk P, Tulipan L, Vattay P, Bogner S, Wayand W. A new bipolar feedback-controlled sealing system for closure of the cystic duct and artery. Surg Endosc 2002;16(5): [6] Harold KL, Pollinger H, Matthews BD, Kercher KW, Sing RF, Heniford BT. Comparison of ultrasonic energy, bipolar thermal energy, and vascular clips for the hemostasis of small-, medium-, and large-sized arteries. Surg Endosc 2003;17: [7] Lee WJ, Chen TC, Lai IR, Wang W, Huang MT. Randomized clinical trial of Ligasure versus conventional surgery for extended gastric cancer resection. Br J Surg 2003;90: [8] Dubuc-Lissoir J. Use of a new energy-based vessel ligation device during laparoscopic gynecologic oncologic surgery. Surg Endosc 2003;17: [9] Yim AP, Rendina EA, Hazelrigg SR, Chow LT, Lee TW, Wan S, Arifi AA. A new technological approach to nonanatomical pulmonary resection: saline enhanced thermal sealing. Ann Thorac Surg 2002;74: [10] Molnar FM, Szantó Z, László T, Lukacs L, Horvath ÖP. Cutting lung parenchyma using the harmonic scalpel an animal experiment. Eur J Cardiothorac Surg 2004;26: [11] Shigemura N, Akashi A, Nakagiri T. New operative method for a giant bulla: sutureless and stapleless thoracoscopic surgery using the Ligasure system. Eur J Cardiothorac Surg 2002;22: [12] Tirabassi MV, Banever GT, Tashjian DB, Moriarty KP. Quantitation of lung sealing in the survival swine model. J Pediatr Surg 2004;39: [13] Shigemura N, Akashi A, Nakagiri T, Ohta M, Matsuda H. A new tissuesealing technique using the Ligasure system for nonanatomical pulmonary resection: preliminary results of sutureless and stapleless thoracoscopic surgery. Ann Thorac Surg 2004;77: [14] Albanese CT, Sydorak RM, Tsao K, Lee H. Thoracoscopic lobectomy for prenatally diagnosed lung lesions. J Pediatr Surg 2003;38:553 5.