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Ann Thorac Surg 1998;65:800-802
© 1998 The Society of Thoracic Surgeons

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Original Articles: General Thoracic

Experience With the Two-Windows Method for Mediastinal Lymph Node Dissection in Lung Cancer

Department of Surgery, Tokai University School of Medicine, Kanagawa, Japan

Accepted for publication September 2, 1997.

Dr Iwasaki, Department of Surgery, Tokai University School of Medicine, Isehara, Kanagawa 259-11, Japan.

	Abstract

Top Abstract Introduction Material and Methods Results Comment References

 
Background. Continuing to refine minimally invasive thoracoscopic surgical procedures, we have established the two-windows method.

Methods. Skin incisions required by this method consist of a 2- to 3-cm skin incision posteriorly, and a 2- to 3-cm skin incision anteriorly in the fourth intercostal space, with the inferior angle of the scapula as the midpoint. We used this method to perform pulmonary lobectomies in combination with thoracoscopy and mediastinal lymph node dissection in 100 consecutive patients with lung cancer (preoperative diagnosis, stage I, T1 N0 M0).

Results. The mean operative time was 2 hours 46 minutes, the mean blood loss was 68.2 mL, and the mean number of mediastinal lymph nodes dissected was 24.3. In developing this minimally invasive thoracoscopic procedure, which facilitates mediastinal lymph node dissection, we realized that it is best performed through the fourth intercostal space. Because the tracheal bifurcation can be seen directly below this level, surgical manipulation in this area can be easily performed. This enables the same extent of mediastinal lymph node dissection as that performed during a standard thoracotomy. Another advantage of this method is that a standard posterolateral thoracotomy incision can be made whenever necessary by simply connecting the two incisions.

Conclusions. We believe that the two-windows method is capable of serving as the standard method for the surgical treatment of stage I lung cancer.

	Introduction

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We began using thoracoscopic surgical procedures at our institution in January 1991 in an attempt to lessen the invasiveness of standard thoracic surgical procedures. In July 1993 we devised an operation that used the two-windows method [1]. After evaluating this method for the treatment of benign diseases, we began applying this method to perform lobectomies and mediastinal lymph node dissections in patients with lung cancer. This work began in January 1994, and initially we found it to be indicated for only a limited number of technically feasible cases. As surgical technique improved, however, it became possible to perform even mediastinal dissections in complicated cases. This procedure compares favorably with lobectomies and lymph node dissections performed by standard thoracotomies. We believe that this method is superior to the standard thoracotomy in various respects, and may well be capable of serving as the standard surgical procedure for lung cancer in patients with limited disease.

	Material and Methods

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The subjects of this study were 100 consecutive patients with a preoperative diagnosis of T1 N0 M0 (stage I) lung cancer in whom an R2 lymph node dissection was possible. The patients underwent operation at our hospital between January 1994 and August 1996. There were 59 men and 41 women with a mean age of 65.6 years (range, 36 to 78 years), and 58.8 years (range, 42 to 78 years), respectively. The histologic types of lung cancer in the men were squamous call carcinoma (32 patients), adenocarcinoma (25), and large cell carcinoma (2 patients). In the women, the histologic types were squamous cell carcinoma (12 patients) and adenocarcinoma (29 patients). All operations were performed under general anesthesia with unilateral pulmonary ventilation. The patients were placed in the lateral position at the beginning of the operation. This made it possible to switch to a standard thoracotomy at any time. Two skin incisions were made in the fourth intercostal space. One was placed 2 to 3 cm posteriorly, and the other 2 to 3 cm anteriorly, using the inferior angle of the scapula as the midpoint. During the procedure, the surgeon usually stands facing the patient’s back; however, depending on the exposure needed, the surgeon may also stand facing the patient’s abdomen. The thoracotomy incision closest to the surgeon was made slightly longer to facilitate tissue manipulation, and the incision furthest away from the surgeon was used for the insertion of the thoracoscope and forceps.

The mediastinal lymph node dissection was performed under video-assisted thoracoscopy using conventional thoracoscopic instruments. Once the intraoperative diagnosis was made and the surgeons confirmed that grossly apparent N2 disease was not present, the azygos vein was sectioned in the right mediastinum. The mediastinal pleura was subsequently reflected, and a lymph node dissection was performed. In the left mediastinum, the ductus arteriosus was sectioned, and careful dissection was performed from the fifth lymph node toward the third lymph node. In the earliest operations, double ligature with silk sutures of the pulmonary vessels was done before tissue resection. Recently, we have begun to use the END GIA 30-2.5 (United States Surgical Corp, Norwalk, CT) during pulmonary lobectomies. The bronchi were sutured with either the Roticulator TA (U.S. Surgical) sutures or the END GIA 30-3.5 (U.S. Surgical).

	Results

Top Abstract Introduction Material and Methods Results Comment References

 
Thoracotomy was performed using the two-windows method in every patient, and no additional incisions were necessary. Pleural adhesions were found in 6 patients; however, they were easily divided. There was never a need to switch over to a standard thoracotomy because of excessive adhesions.

The time required to complete a mediastinal lymph node dissection ranged from 15 minutes to 2 hours 20 minutes (mean, 1 hour 12 minutes). Completion of a pulmonary lobectomy ranged from 40 minutes to 2 hours (mean, 1 hour 24 minutes). The number of lymph nodes removed during a mediastinal lymph node dissection ranged from 12 to 42 (mean, 24.3). At postoperative histopathologic examination, the lymph nodes were classified as N0 in 82 patients, N1 in 10, and N2 in 8 patients. Blood loss ranged from 5 to 480 mL, with an average of 68.2 mL. Bronchi were divided and sutured at the same time with either a Roticulator TA or an END GIA 30-3.5 at 107 sites in the 100 patients. An average of 2.4 END GIA 30-2.5 sutures were used to divide and suture the pulmonary artery and vein. An average of 0.67 END GIA 30-3.5 sutures and 0.37 END GIA 60-4.8 sutures were needed for a division of the interlobar tissues.

Pulmonary function was evaluated by determining forced vital capacity, forced expiratory volume in 1 second (FEV₁), and FEV₁% preoperatively and at 1 month postoperatively. Preoperative pulmonary function tests yielded the following values: FEV, 2.92 ± 0.68 L; FEV₁, 2.46 ± 0.6 L; and FEV₁%, 81.2% ± 0.61%. Pulmonary function testing 1 month postoperatively yielded: forced vital capacity, 2.43 ± 0.6 L; FEV₁, 2.35 ± 0.7 L; and FEV₁%, 76.8% ± 8.9%.

An evaluation of postoperative pain revealed that the first consecutive 20 patients required analgesics until postoperative day 20 because we performed wide retraction of the intercostal space. Almost all of the subsequent patients, however, required analgesics only until postoperative day 7, because the rib retraction was kept to a minimum.

	Comment

Top Abstract Introduction Material and Methods Results Comment References

 
Thoracoscopic procedures have been widely performed in recent years; however, the thoracotomy incision site has varied from institution to institution. The video-assisted thoracoscopic lobectomy was initially reported as a method for treating lung cancer by Lewis [2], Roviaro and associates [3] and Kirby and colleagues [4]. This procedure, however, required at least three separate skin incisions, and there were no reports of mediastinal lymph node dissections being performed. In 1994, McKenna [5] began to perform mediastinal lymph node dissections; however, the surgical technique and instruments used were not clearly described. The two-windows method allows mediastinal lymph node dissection to be performed using conventional surgical instruments as in a standard thoracotomy. Because the surgical field is enlarged and illuminated using thoracoscopy, this method offers the advantage of completing a thorough lymph node dissection. The total number of lymph nodes removed by this method appears to be the same as that performed during a standard thoracotomy.

This two-windows method is the least invasive method currently available. Knowing the appropriate extent to which the procedure’s invasive nature can be minimized is important. It is also important to carry out the thoracoscopic procedure safely, while maintaining the same quality of surgical outcomes as the open thoracotomy. The two-windows method appears to enable patients to recover more quickly, with a higher level of functioning than they would otherwise have after an open thoracotomy. Clearly this minimally invasive approach is the direction that thoracic surgery should take in the future. When we first began to perform thoracoscopic operations, we conducted the operation at three sites: one skin incision large enough to insert a hand into the thoracic cavity; another site for insertion of the thoracoscope; and a third site for retraction and tissue manipulation. We were performing thoracoscopy combined with an open operation, where the surgeon’s hand made direct contact with lung tissue. Although there were no problems in performing a lobectomy with this earlier method, mediastinal lymph node dissection was difficult because of a restricted field of view. It was often impossible to perform the dissection with confidence, particularly when exploring the anterior surface of the tracheal bifurcation. We began to realize that it would be possible to perform surgical maneuvers equivalent to the three incisions method by simply inserting a video camera and forceps simultaneously as a mean of further decreasing surgical invasion. Considering mediastinal lymph node dissections in conventional lung cancer operation to be important, we devised a method in which two small thoracotomies are made in the fourth intercostal space on either side of the inferior scapular angle. The benefits of this method are not only a decrease in the extent of surgical wounds, but also that lymph nodes around the tracheal bifurcation can be easily dissected. This is because the tracheal bifurcation lies directly beneath the site of the thoracotomy. Because one looks up at the tracheal bifurcation in the conventional thoracoscopic procedure, there is often a risk of being unable to tell whether the lymph nodes on the anterior surface of the bifurcation have been completely dissected. This is because the right main pulmonary artery is adjacent to the anterior surface of the tracheal bifurcation but often cannot be seen in the conventional thoracoscopic operation. With our method, it is possible to identify the tracheal bifurcation directly below, and it is easy to complete the mediastinal lymph nodes dissection without the risk of hemorrhage from the pulmonary artery. In addition, our procedure appears to be superior to a conventional thoracotomy in terms of blood loss, operative time, postoperative pain, and length of hospital stay. Fewer automatic sutures are used, and almost all blood vessels can be tied off using conventional ligatures.

The operation can proceed with a posterior skin incision of 2 cm and an anterior incision of 2 cm. However, the resected lung must be removed, and automatic anastomosis machines are used; therefore, at the present time it is impossible to make the posterior skin incision scar any smaller than 3 cm. Thoracoscopic operation involves less surgical invasion and is now possible to perform in a shorter period of time compared to an open thoracotomy. It is beneficial in patients with poor pulmonary function, in elderly patients, and in patients in whom it would be otherwise impossible to perform a conventional thoracotomy. For these reasons, we believe that the surgical indications for thoracoscopic procedures will expand.

We use a Univent (Fuji Systems Cooporation. Tokyo, Japan) [6] for isolated pulmonary ventilation in all thoracotomy cases. This tube is occasionally useful during thoracoscopic operation. Use of a Univent makes it possible to selectively maintain atelectasis in only the lobe to be resected, allowing the operation to proceed with the other lobes fully ventilated. This is an essential technique in patients with poor pulmonary function.

In conclusion, we believe that the two-windows method may become a standard procedure for thoracoscopic resection of lung cancer.

	References

Top Abstract Introduction Material and Methods Results Comment References

 

1. Iwasaki M, Nishiumi N, Inoue H, et al. Thoracoscopic surgery for lung cancer using the two small skin incisional method. J Cardiovasc Surg 1996;37:79-81.[Medline]
2. Lewis RJ Simultaneously stapled lobectomy: a safe technique for videoassisted thoracic surgery. J Thorac Cardiovasc Surg 1995;109:619-625.[Abstract/Free Full Text]
3. Roviaro G, Varoli F, Rebuffat C, et al. Major pulmonary resections: pneumonectomies and lobectomies. Ann Thorac Surg 1993;56:779-783.[Abstract]
4. Kirby TJ, Mack MJ, Landreneau RJ, et al. Lobectomy video-assisted thoracic surgery versus muscle-sparing thoracotomy. J Thorac Cardiovasc Surg 1995;109:997-1002.[Abstract]
5. McKenna RJ Lobectomy by video-assisted thoracic surgery with mediastinal node sampling for lung cancer. J Thoracic Cardiovasc Surg 1994;107:879-882.[Abstract/Free Full Text]
6. Ovassapian A Conduct of anesthesia. In: Shields TW, ed. General thoracic surgery, 4th ed. Baltimore: Williams & Wilkins, 1994:314-316.

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Masayuki Iwasaki Kichizo Kaga Hiroshi Inoue Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Iwasaki, M. Articles by Inoue, H. Search for Related Content PubMed PubMed Citation Articles by Iwasaki, M. Articles by Inoue, H.