minimally invasive techniques

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1 minimally invasive techniques New Electroablation Technique Following the First-Line Stapling Method for Thoracoscopic Treatment of Primary Spontaneous Pneumothorax* Noriyoshi Sawabata, MD, FCCP; Masahito Ikeda, MD; Akihide Matsumura, MD; Hajime Maeda, MD; Shinichiro Miyoshi, MD; and Hikaru Matsuda, MD Study objectives: A new tip for the electroablation of pneumocysts was examined clinically as a second-line method for stapled resection of pneumocysts during video-assisted thoracoscopic surgery (VATS). Design: A trial to assess feasibility. Settings: National referral hospitals. Patients: One hundred seven patients were studied, of whom 99 patients were eligible for the study (85 men and 14 women; age range, 15 to 69 years; median age, 23 years), who had undergone VATS for primary spontaneous pneumothorax between July 1996 and June Apical pneumocysts were resected employing staplers, and residual pneumocysts, if present, were electroablated employing a new tip for the electrosurgery unit (ball shape, 8 mm in diameter, and made of stainless steel). Measurements and results: Thirty-three patients (33%) underwent electroablation only for small (< 2 cm in diameter) pneumocysts (group S), and 11 patients (11%) underwent electroablation for large (> 2 cm in diameter) pneumocysts (group L). The remaining 55 patients (56%) did not undergo electroablation because there were no residual pneumocysts (group N). There were no complications during surgery. The duration of the operation was significantly shorter (about 20 min on average) for group N, but there was no significant difference in the amount of blood loss, the number of applied staples, the duration of drainage, and the duration of hospital stay. Group S achieved a 100% relapse-free rate (33 of 33 patients), group L achieved a 64% relapse-free rate (7 of 11 patients), and group N achieved an 89% relapse-free rate (49 of 55 patients) [group S vs group N, p 0.08; group L vs group N, p 0.001; and group S vs group L, p 0.002]. Conclusion: Electroablation with the M-tip is feasible as a second-line method for the treatment of small pneumocysts following the stapling technique during VATS. (CHEST 2002; 121: ) Key words: ablation; bulla; electrosurgical unit; spontaneous pneumothorax; video-assisted thoracoscopic surgery Abbreviations: PSP spontaneous pneumothorax; VATS video-assisted thoracoscopic surgery Primary spontaneous pneumothorax (PSP) has been treated employing video-assisted thoracoscopic surgery (VATS) with less invasion than using thoracotomy. 1,2 The conventional method for bulla resection, suturing the pleura using a needle and thread with a needle holder following removal of the *From the Thoracic Surgery Study Group of Osaka University, Osaka, Japan. This article was presented at CHEST 2000, San Francisco, CA, October 25, bulla, is difficult in the small operative space allotted for VATS, therefore staplers are applied as a firstline method for bulla resection in patients with PSP using VATS Although stapled resection may be reliable in preventing the occurrence of relapse Manuscript received December 5, 2000; revision accepted May 31, Correspondence to: Noriyoshi Sawabata MD, FCCP, Division of Surgery, Toneyama National Hospital, Toneyama, Toyonaka, Osaka Japan; nori@toneyama.hosp.go.jp CHEST / 121 / 1/ JANUARY,

2 pneumothorax following VATS for PSP, staplers may have anatomic and quantitative limitations. They may be dangerous when they are applied to neighboring blood vessels, and staple cassettes are too expensive to use in large numbers. Ablation is an inexpensive method of resecting pneumocysts and may be safer than stapled resection in locations that are close to blood vessels. Electrocautery and lasers have been reported to be effective in some patients However, they are not commonly used because it is difficult to treat pneumocysts with electrocautery using conventional tips without causing damage, and lasers are expensive and not so ubiquitous. A new tip for electrosurgery (the M-tip) has become available. It is ball-shaped, 8 mm in diameter, made of stainless steel, and gives adequate shrinkage of the pleura with little trauma. 14 We conducted a study setting the primary end point as the calculation of the relapse-free rate and the secondary end point as the assessment of adverse effects in order to assess the feasibility of electroablation using the M-tip as a second-line method for stapled resection of pneumocysts during VATS. Background of Patients Materials and Methods From July 1996 to June 1998, 107 patients with PSP who had not undergone any surgical treatment, pleurodesis, or medical thoracoscopy were entered into this study. There were 93 men and 14 women, with an age range of 15 to 69 years (median age, 23 years). There was no patient with an emphysematous lung. Even in the cases of elderly patients, the remaining lung was almost normal except for pneumocyst lesions. The criteria for ineligibility were conversion to thoracotomy for any reason or the absence of pneumocysts. After applying the ineligibility criteria, 8 patients were excluded, leaving 99 patients (85 men and 14 women; age range, 15 to 69 years; median age, 23 years). Among these 99 patients, 28 patients underwent VATS because of persistent air leak (ie, an air leak that lasts for 7 days despite chest drainage), and 71 patients underwent VATS because of repeat relapse (ie, spontaneous pneumothorax that occurred twice or more despite suction therapy using chest tube drainage). Figure 1. The M-tip ( ball shape, 8 mm in diameter, and made of stainless steel) is shown. This tip can be used with any electrosurgical unit. Apical lesions were resected employing staplers (model EZ-45; Ethicon; Tokyo, Japan). Following the stapled resection, the lung was inflated and observed through video-assisted thoracoscopy. Residual pneumocysts, if present, were ablated by an electrosurgical unit employing a new tip that was ball-shaped, 8 mm in diameter, and made of stainless steel (M-tip; Senko Ika; Tokyo, Japan). This tip can be used with any electrocoagulator. The ball tip is illustrated in Figure 1. The power level was set at 20 W using one unit (Bovie X10 U; Hokusan; Tokyo, Japan) and 10 W using another unit (MS-BM2 U; Senko Ika), and both units were set on spray coagulation mode. Pneumocysts soaked with normal saline solution were rubbed with the tip of the electrocoagulator to obtain adequate shrinkage. Treatment ceased on white coloration with shrinking, as shown in Figure 2. Pleurodesis was not undertaken, because the outcome of iatrogenic pleuritis remains unknown. Statistical Analysis Statistical analyses of the data were performed using factorial analysis of variance with a commercially available software package (StatView, version 5.0; Abacus Concepts; Berkeley, CA). Statistical significance was calculated using Fisher s Exact Test, for comparison of the relapse-free rates, and the analysis of variance system for the backgrounds of the patients or for comparing perioperative parameters. Significance was assumed when the calculated p value was Surgical Techniques Figure 2. On the completion of the clearing process using normal saline solution, the wet pneumocyst (left top) is treated by the application of right touch movement in spray coagulation mode using the M-tip through the access port (right top). The pneumocyst quickly shrinks at the moment when the M-tip reaches it (left bottom). Treatment is discontinued with the appearance of white coloration and shrinking of the pneumocyst (right bottom). 252 Minimally Invasive Techniques

3 Results Among the 99 eligible patients, 33 patients (33%) underwent electroablation using the M-tip for only small pneumocysts (ie, blebs or bullae 2cmin diameter; group S), 11 patients (11%) underwent electroablation for large pneumocysts (ie, those 2 cm in diameter; group L), and the remaining 55 patients (56%) did not undergo electroablation because there were no residual pneumocysts (group N). The following demographic parameters were not statistically different among the three groups: mean ( SD) age: group S, years; group L, years; and group N, years (p 0.3); and gender: group S, 28 men and 5 women; group L, 10 men and 1 woman; and group N, 47 men and 8 women (p 0.9). Treatment of Pneumocysts The pneumocysts were treated with staplers or by electrocautery using the M-tip without any complications. One hundred six lesions were resected with staplers. A total of 55 lesions were ablated by electrocautery (ovoid surface, 32 lesions; edge, 32 lesions; site close to a blood vessel, 5 lesions; and place near the staple, 4 lesions). Forty-four lesions were small pneumocysts ( 2 cm in diameter), and 11 were large pneumocysts ( 2 cm in diameter). Operative and Postoperative Parameters There were no complications during surgery. Comparing the three groups, the duration of surgery was significantly shorter in group N. On the other hand, there were no significant differences in the amount of blood loss, the applied number of staple cassettes, the duration of drainage, and the duration of hospital stay (Table 1). Relapse-Free Rate There were 10 relapses within 1 year of surgery. Group S achieved a 100% relapse-free rate (33 of 33 patients), group L achieved a 64% relapse-free rate (7 of 11 patients), and group N achieved an 89% relapse-free rate (49 of 55 patients). There was no statistically significant difference between group S and group N (p 0.08). By contrast, there were statistically significant differences between group L and group N (p 0.001), and between group S and group L (p 0.002) [Fig 3]. Discussion VATS has been used for the treatment of PSP. Many studies 3 10 of patients have confirmed the usefulness of VATS. During VATS for PSP, staplers are the most common devices used to resect pneumocysts, inasmuch as they are easy to handle and it is safe to resect pneumocysts at almost any location with them. However, staplers may pose anatomic and quantitative limitations, they may be dangerous when applied to neighboring blood vessels, and staple cassettes are too expensive to use in large numbers. The ablation of pneumocysts employing electrocautery or a laser may be safer than the stapling technique when the ablation is applied to pneumocysts close to a blood vessel, because both techniques shrink the pneumocyst with little damage. Moreover, ablation is inexpensive using electrocautery or a laser when many pneumocysts are treated in the same operation, thus making the use of disposable staple cassettes unnecessary for ablation. Once a unit for ablation is set up, there is little difference in the cost between the treatment for a single pneumocyst and for multiple pneumocysts. Suturing or loop ligation also is used as second-line method but ablation is easier to perform than either of these methods. Wakabayashi 11 reported in 1989 that thoracoscopic electrocautery in the treatment of PSP was safe and effective with a success rate of 90% when it was used with a conventional tip. However, this technique was controversial at that time because it was difficult to ablate pneumocysts using a conventional tip without adverse effects, such as the rupture of the pneumocysts during surgery or excessive burning of the lung, possibly leading to delayed pneumothorax. 18 LoCicero and colleagues reported in the late 1980s that a carbon dioxide laser was more effective than electroablation in sealing air Table 1 Operative and Postoperative Variables* Variable Group S Group L Group N p Value Operation duration, min Blood loss, g Staple cassettes, No Drainage, d Hospital stay, d *Values given as mean SD, unless otherwise indicated. CHEST / 121 / 1/ JANUARY,

4 Figure 3. Relapse-free rates and comparisons for all three groups. leaks from the lungs. Following these studies, Wakabayashi and his coworkers 12 reported in 1990 that it was possible to treat all types of pneumocysts causing spontaneous pneumothorax with the use of a carbon dioxide laser. However, it was laborious to use a carbon dioxide laser in thoracoscopic surgery because the handle was so rigid and large. Following the carbon dioxide laser, the Nd-YAG laser, which can be used with a thin flexible wire, was developed. The Nd-YAG laser was shown to be effective in sealing air leaks from the surface of the lung 22 and was applied by Sharpe et al 23 in 1994 in thoracoscopic treatment of spontaneous pneumothorax as a useful therapeutic option. The Nd-YAG laser has become the most common device employed for the treatment of pneumocysts. However, lasers are less ubiquitous and more expensive than electrosurgical units. Therefore, conventional inexpensive electrocautery is satisfactory as a second-line method for shrinking pneumocysts following stapled resection. The M-tip, which we applied in this study, can shrink the pleura as effectively and safely as the Nd-YAG laser in a human lung. 14 The large ball tip is less curved than the conventional small tip, a design that allows the M-tip to treat a larger area. Coagulation of the lung caused by ablation contributes to the shrinkage of the connective tissue, and so the reduced volume of the lung is limited. 24 When a large pneumocyst is shrunk by heat, there still remains a downsized pneumocyst that may have the potential to cause pneumothorax. It is possible that resection is better than the M-tip for resecting a pneumocyst of 2 cm. On the other hand, a small pneumocyst leaves little space inside following ablation and has coagulation of the parenchyma around it, so the potential for relapse may be low. As seen in this study, the relapse-free rate for patients who underwent ablation with the M-tip for large pneumocysts was approximately 64%. These data suggest that the application of electrocautery for pneumocysts is limited. Therefore, the use of ablation for a large pneumocyst without pleural treatment is not recommended. The relapse might be prevented if some pleural treatment had been applied. By contrast, there was no relapse of pneumothorax in patients who underwent ablation with the M-tip for only small pneumocysts following first-line stapled resection for pneumocysts. In the patients who underwent only first-line stapled resection for pneumocysts, 11% of patients had a relapse of pneumothorax within a year. This may show that we might have been able to notice remaining small pneumocysts after the stapled resection, and if we had found and ablated them during the operation, the relapse might have been prevented. The relapse rate of 11% for patients who underwent only stapled resection for pneumocysts seems to be high, and so pleurodesis might be recommended. However, the outcome of the pleuritis caused by pleurodesis remains unclear. Pleural adhesion will be a cause of restriction of respiration, and it will be difficult to operate on the patient to treat another disease. As a policy at our institutes, we do not indicate pleurodesis in the initial operation for patients with PSP, because pleurodesis is not necessary in 90% of patients with PSP who underwent surgery. Conclusion In the treatment of PSP employing VATS, when we combined a stapling technique for apical pneumocysts and the new electroablation for the remaining pneumocysts, 44% of the patients underwent electroablation using the M-tip for pneumocysts without any complications during the operation and in the postoperative period. No relapse occurred when the new electroablation was applied to small pneumocysts, even when apical pleurodesis was not undertaken. Electroablation using the M-tip for pneumocysts is feasible as a second-line method for small pneumocysts following stapled resection during VATS. References 1 Waller DA, Forty J, Morritt GN. Video-assisted thoracoscopic surgery versus thoracotomy for spontaneous pneumothorax. Ann Thorac Surg 1994; 58: Kim KH, Kim HK, Han JY, et al. Transaxillary minithoracotomy versus video-assisted thoracic surgery for spontaneous pneumothorax. Ann Thorac Surg 1996; 61: Melvin WS, Krasna MJ, McLaughlin JS. Thoracoscopic management of spontaneous pneumothorax. Chest 1992; 102: Minimally Invasive Techniques

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