minimally invasive techniques VATS (Video-Assisted Thoracic Surgery) of Undefined Pulmonary Nodules* Preoperative Evaluation of Videoendoscopic Resectability Christian D. Schwarz, MD; Franz Lenglinger, MD; josef Eckmayr, MD; Norbert Schauer, MD; Peter Hartl, MD; and Klaus H. Mayer, MD Peripheral undefined pulmonary nodules have become a favorable indication for the videoendoscopic approach in thoracic surgery. In our latest experience, we also successfully applied this technique in centrally located lesions of the lung. In reviewing our first 29 cases, we looked for preoperative features of videoendoscopic resectability. From March 1992 to September 1993, 29 patients underwent videothoraeoscopy for undefined pulmonary nodules at our hospital. This group consisted of 17 men and 12 women (aged 25 to 77 years). Pulmonary nodules of this group of patients were defined as centrally located when close attachement to the segmental or subsegmental bronehiopulmonary unit was observed and/or the distance to the visceral pleura exceeded 1 mm. Nodules that did not meet any of these criteria were hence interpreted as peripheral lesions. In the course of 21 excisions of peripheral lesions, we had to convert to open thoracotomy only once for anatomic reasons. When using the video-assisted thoracic surgery (VATS) approach for centrally located lesions, we succeeded in removing four of six. We failed only if the le- P eripheral undefined pulmonary nodules have become a favorable indication for the videoendoscopic approach in thoracic surgery.1 Yet, intraoperative identification of a lesion as well as the decisionmaking process of whether a centrally located lesion is still appropriate for the endoscopic approach remains debatable. In our latest experience, we successfully used this technique also in centrally located lesions. While reviewing our first 29 cases, we looked for preoperative features of videoendoscopic resectability. *From the Departments of Thoracic and Cardiovascular Surgery (Drs. Schwarz, Schauer, and Hartl), Pulmonology (Drs. Eckmayr and Mayer), and (Dr. Lengliner), General Hospital Wels, Wels, Austria. Manuscript received December 8, 1993; revision accepted February 9, 1994. Reprint requests: Dr. Schwarz, AKH-WELS, Grieskirchnerstrasse 42, 46 Wels, Austria sions were located in the upper lobe but could easily apply the technique for centrally located lesions in the lower lobes. In conclusion, undefined peripheral pulmonary nodules are a favorite indication for VATS. Centrally located pulmonary nodules of the lower lobes can often be managed easily by VATS, especially if the interlobar fissure extends to the stem of the pulmonary artery. Centrally located pulmonary nodules in the upper lobes may not be suitable for the VATS approach due to the special anatomic arrangement of the upper lobe segmental arteries and bronchioles. (Chest 1994; 16:157-74) CT=computed tomography; V ATS=video assisted thoracic surgery Key words: endoscopic resectability; undefined pulmonary nodule; VATS, video-assisted thoracic surgery Patients MATERIAL AND METHODS From March 1992 to September 1993, 29 patients underwent videothoracoscopy for undefined pulmonary nodule at our hospital. This group consisted of 17 men and 12 women ranging in age from 25 to 77 years. Definition of Central Lesions To define a lesion as peripheral or central, we measured the distance to the nearest visceral pleura by computed tomographic (CT) scan. This included the interlobar and mediastinal parts of the pleura. In addition, we examined the lesion's attachment to segmental or subsegmental branches of the pulmonary artery or the bronchial system by CT scan. A lesion was defined as central if it was attached close to the segmental or subsegmental bronchioarterial unit and/ or if the distance to the nearest part of the visceral pleura was more than 1 mm. Pleural distance of mm meant subpleural location, including the interlobal and mediastinal site. 157 Video-Assisted Thoracic Surgery of Undefined Pulmonary Nodules (Schwarz eta/)
1-+-1-i 3mm FIGURE l. Localization, patient number, and actual size of the lesions. Shadowed circle indicates excision by only minimally invasive technique; black circle, we had to open up the chest. Preoperative evaluation included chest radiographs, CT, coagulation studies, and pulmonary function tests. Before surgery, pulmonary nodules were located by CT scan and stained with methylene blue. Technique All procedures were performed in the operating room. After institution of general anesthesia, the patient was intubated with a double-lumen endotracheal tube and placed in a lateral decubitus position. A 2.-cm incision was made in the midaxillary line in the seventh intercostal space. After initiation of single-lung ventilation, an open-ended cylindrical plastic tube was introduced through the incision to serve as a conduit through which a rigid 1.-mm thoracoscope with a 3 degree lens was inserted. Carbon dioxide insufflation was never used. After exploration of the thoracic cavity, two additional trocars were usually introduced to allow manipulation and examination of the entire lung. We sought to keep these incisions on an imaginary standard thoracotomy incision that allowed us to incorporate the small thoracoscopy incisions into the thoracotomy incision when thoracotomy was required. Intrapleural adhesions were divided by sharp dissection with endoscopic scissors. Collapse of the lung facilitated identification of the lesions, which became effaced against the surrounding atelectatic pulmonary tissue, especially in the lower lobes. Introduction of a palpating finger through one trocar site helped identify and evaluate the pulmonary lesion. After detection of the lesion, a conventional lung grasping forceps was introduced to get hold of the specimen securely. Wedge excision was performed using a percutaneous stapling device (Endo-GIA stapler; US Surgical). For wedge or keel resection, up to six cartridges of the stapling device were necessary. The specimen was removed through one of the incisions and sent for examination. For the surgical procedure, we used standard thoracic surgery instruments as lung grasping forceps, clamps mostly without a trocar, and hook electrodes or endoshears. After the surgical procedure, the whole thoracic cavity was inspected for hemostasis, especially staple lines and trocar sites. One or two 24-F chest tubes were then guided to the apex of the Table!-Patient Number, Age, Sex, Diagnosis, Histologic Findings, and Operating Time Patient No. Operating Time, min Age, yr/ Sex Diagnosis Histologic Result (VATS) 1/ 42/ F Pulmonary nodule left lower lobe Tuberculoma 7 2/ 4/ M Pulmonary nodule left lower lobe Amyloid nodule 3/ 69/ M Pulmonary nodule middle lobe Silicofibrosis 2 4/ 43/ M Pulmonary nodule left lower lobe Hamartoma 5 5/ 57/ F Pulmonary nodule lingula Inflammatory lesion 45 6/ 25/ F Pulmonary nodule right lower lobe Tuberculoma 65 7/ 74/ F Pulmonary nodule left upper lobe T1 squamous cell carcinoma 2 8/ 51 / M Pulmonary nodule left lower lobe Tuberculoma 3 9/ 77/ M Pulmonary nodule right upper lobe Metastasis of colon carcinoma 25 1/ 52/ F Pulmonary nodule right lower lobe Tuberculoma 11 / 64/ F Pulmonary nodule left lower lobe Unspecific peribronchiolitis 2 12/ 66/ M Pulmonary nodule left lower lobe Subpleural, anthracotic lymph node 25 13/ 71 / M Pulmonary nodule left lower lobe Chronic carnifying pneumonia 14/ 64/ M Pulmonary nodule left lower lobe Hamartoma 9 15/ 57/ M Pulmonary nodule left lower lobe Hamartoma 15 16/ 41 / F Pulmonary nodule left lower lobe Metastasizing leiomyosarcoma 15 17/ 61 / M Multiple pulmonary nodules bilateral Metastasizing leiomyosarcoma 15 18/ 57/ M Pulmonary nodule middle lobe Subpleural, anthracotic lymph node 2 19/ 69/ F Tumor left upper lobe Benign mesothelioma 15 2/ 33/ M Pulmonary nodule left lower lobe Hamartoma 15 21 / 65/ M Pulmonary nodule right upper lobe Hamartoma 22/ 41 / F Tumor middle lobe Fibrous pleural tumor 23/ 59/ M Pulmonary nodule middle lobe Fibroma 15 24/ 71/ F Pulmonary nodule left lower lobe Hamartoma 15 25/ 69/ F Pulmonary nodule right upper lobe Leiomyosarcoma 26/ 62/ M Pulmonary nodule middle lobe Anthracotic lymph node 1 27 / 51 / F Pulmonary nodule right upper lobe Adenocarcinoma 28/ 65/ M Pulmonary nodule left lower lobe Metastases hypernephroma 4 29/ 64/ M Pulmonary nodule right upper lobe Focal anthracosis 7 CHEST / 16 / 5 / NOVEMBER, 1994 1571
Table 2-Patient Number, Age, Sex, Indications, Minimal Distance to Visceral Pleura, Classification, Surgical Procedure, and Diameter of Pulmonary Nodules Patient No. / Age, yr/ Sex Diagnosis Minimal Distance, mm Classification Surgical Procedure, Diameter (mm) 1/ 42/ F Pulmonary nodule left lower lobe 2/ 4/ M Pulmonary nodule left lower lobe 3/ 69/ M Pulmonary nodule middle lobe 4/ 43 / M Pulmonary nodule left lower lobe 5/ 57/ F Pulmonary nodule lingula 6/ 25/ F Pulmonary nodule right lower lobe 7 /74/ F Pulmonary nodule left upper lobe 8/ 51/ M Pulmonary nodule left lower lobe 9/ 77/ M Pulmonary nodule right upper lobe 1/ 52/ F Pulmonary nodule right lower lobe 11 / 64/ F Pulmonary nodule left lower lobe 12/ 66/ M Pulmonary nodule left lower lobe 13/ 71 / M Pulmonary nodule left lower lobe 14/ 64 / M Pulmonary nodule left lower lobe 15/ 57 / M Pulmonary nodule left lower lobe 16/ 41 / F Pulmonary nodule left lower lobe 17/ 61 / M Multiple pulmonary nodules bilateral 18/ 57/ M Pulmonary nodule middle lobe 19/ 69/ F Tumor left upper lobe 2/ 33/ M Pulmonary nodule left lower lobe 21 / 65/ M Pulmonary nodule right upper lobe 22/ 41 / F Tumor middle lobe 23/ 59/ M Pulmonary nodule middle lobe 24/ 71 / F Pulmonary nodule left lower lobe 25 / 69/ F Pulmonary nodule right upper lobe 26/ 62/ M Pulmonary nodule middle lobe 27 / 51 / F Pulmonary nodule right upper lobe 28/ 65/ M Pulmonary nodule left lower lobe 29/ 64/ M Pulmonary nodule right upper lobe 5 2 5 2 13 24 15 31 12 2 Peripheral Excision (16) Peripheral Thoracotomy, excision (1) Central Excision (8) Peripheral Excision Peripheral Excision (8) Peripheral Excision with margine (2) Peripheral Excision (7) Peripheral Excision ( 1) Central Thoracotomy, excision (1) Central Excision (8) Peripheral Excision ( 1) Central Thoracotomy (no equipment) Central Adhesiolysis, excision (12) Peripheral Excision (17) Peripheral Excision ( 1) Peripheral Excision (8) Peripheral Excision (7) Central Excision (12) Peripheral Thoracotomy (bleeding) Peripheral Thoracotomy (problems equipment) Peripheral Excision (2) Peripheral Excision (ll) Central Thoracotomy (central, 25) Central Thoracotomy (central, lobectomy, 3) Peripheral Excision (16) Peripheral Excision ( 1 ), adhesions chest and posterior to the lung through the trocar sites. The procedure was terminated after closure of the remaining trocar sites. Suction to the chest tubes was not established. RESULTS The histologic results of the resected specimens and the operating time are listed in Table l. The median diameter of the excised pulmonary nodule was 1 mm (range, 7 to 7 mm). Minimal distance to either part of the visceral, pleura, including the interlobar and mediastinal parts, is listed in Table l. Localization, size, and resectability of lesions are shown in Figure l. Figure 2 gives the CT scans of two centrally located lesions in the left lower lobe, both successfully excised by only minimally invasive means. Note the close attachement of the nodule to the segmental artery in Figure 2, top. Twenty-one lesions were classified as peripheral and eight lesions were classified as central as shown in Table 2. The distance from the visceral pleura varied between 13 and 31 mm for central lesions and and 5 mm for peripheral lesions. All central lesions had close relationship to the segmental or at least subsegmental branches of the pulmonary artery or bronchial tree. Intraoperative lung collapse made identification and grasping of the lesions very easy. Even centrally located lesions become effaced through the pleural surface if the lung collapses totally; however, it was much more pronounced in the lower lobes than in the upper lobes. We had to convert to open thoracotomy, ie, anterolateral thoracotomy not longer than 1 to 12 em, seven times. In patients 2, 13, and 22, there were technical problems with the endoscopic equipment, ie, misfitting of different devices when we first tried different brands of endoscopic equipment, and there was dysfunction of light source. Patient 21 had bleeding that occurred either because of preoperative methylene blue staining or because of puncture with a trocar right into pleural adhesions. Peripheral parenchymal lesion of lung led to an unseen situation in the operating field; conversion to open thoracotomy followed. In patient 1, the nodule was located in the right lower lobe 2 mm from the parietal pleura. In addition, it was very far dorsal. Retrospectively, it should have been possible to excise changing the trocar sites and reposition the patient. Both patients 25 and 27 harbored rather big nodules located centrally in the right upper lobe. Even through thoracotomy they were removable only by a very deep keel excision. 1572 Video-Assisted Thoracic Surgery of Undefined Pulmonary Nodules (Schwarz eta/)
FIGURE 2. Top, CT scan in the transverse plane showing 12-mm hamartoma in the left lower lobe (patient 14). Note close relationship to the branching of the laterobasal segmental artery. Bottom, CT scan in the transverse plane showing 12-mm hamartoma in the left lower lobe (patient 2). Note least distance to mediastinal pleura of 31 mm. All pulmonary lesions diagnosed radiographically in this series were able to be thoracoscopically located and identified. Twenty-two of 29 pulmonary nodules could be excised only by minimal invasive technique. Besides one bleeding (patient 21), there were no complications in the perioperative or postoperative period. One patient with an undefined pulmonary nodule that proved to be a squamous cell carcinoma had markedly reduced FEY 1 ; and therefore, any open thoracotomy procedure was not feasible. In all cases, intraoperative blood loss was minimal. Median operating time was 2 min (range, 15 to 9 min). DISCUSSION Distribution of histologic type of the excised specimens in our group of patients is similar to previously published series. 2 It is important to mention that in measuring the lesions' minimal distance to the viscera! pleura, we included the interlobar fissure and the mediastinal parts of the visceral pleura. The distance of the central lesions varied between 13 and 31 mm. Depending on the size of a lesion, 31 mm was the most central a nodule could be situated. Subpleural lesions were reclassified as peripheral when our criteria had been met, even if preoperatively they appeared as central on CT scan. This led to the high proportion of peripheral lesions. We have no explanation why the left lower lobe obviously is a favorite localization for pulmonary nodules in our group of patients. Taking into account that in patient 1 VATS could have been successful when changing trocar sites and repositioning the patient, it is obvious that as shown in Table 3, we had to open up the chest for reasons of anatomic irresectability by minimally invasive means only in two cases (patients 25 and 27) of very centrally located lesions in the right upper lobe. On the other hand, we easily could excise three centrally located lesions (patients 11, 14, and 2) in the left and right lower lobe by VATS. We may postulate that the differences in resectability between upper and lower lobes are due to the different arrangement of the segmental branches of the bronchopulmonary unit. The bronchi 6 through 9 (1) are arranged much more in one plane than the bronchi 1 through 5, which are ordered more divergent like the fingers of a hand holding a tennis ball. This different anatomy is according to the fact that lesions in the lower lobes become much better effaced against the surrounding collapsed pulmonary tissue than in the upper lobes and that access to lower lobe pulmonary nodules by minimally invasive means is easier than in the upper lobes. An additional feature for easier access to a central lesion is a deep extension of the greater interlobar fissure, in the best case toward the stem of the pulmonary artery. However, the extension of the interlobar fissure cannot be evaluated preoperatively. Because of these observations, we tend to exclude patients with centrally located lesions of the upper Table 3-Reasons for Conversion to Thoracotomy, Distance to Visceral Pleura, and Location if Lesion Was Classified as Central Patient No. Reason 2 Problems equipment 1 Central lesion, distance to pleura 2 mm, right lower lobe, far dorsal 13 Problems equipment 21 Bleeding 22 Problems equipment 25 Central lesion, distance to pleura 12 mm, right upper lobe 27 Central lesion, distance to pleura 2 mm, right upper lobe CHEST / 16 / 5 / NOVEMBER, 1994 1573
lobes according to the criteria mentioned above from the primarily videoendoscopic approach. The median operating time of 2 min is as short as in open thoracotomy or even shorter. So in our experience, VATS does not increase operating time. In our experience, preoperative injection of methylene blue guided by sonography or CT scan right into the lesion helps to locate it easily, although it might not be necessary. It has to be mentioned that what you see is the stained area of the visceral pleura under which the lesion is located. How deep under the pleural surface the lesion is located is hard to estimate by optical means. In this case, palpation directly or with an instrument is very helpful. General surgeons know the J-wire used in mammary surgery helps localize the lesion; however, the wire was very easily retracted during manipulating for thoracoscopy. The collapse of the lung during onelung ventilation pulled the wire out of the pulmonary tissue. Our favorable method of intraoperative localization is to palpate right through the first incision even before the lung collapses totally. That ensures the surgeon of the correct localization of the lesion and gives additional information about its character. Usually ports limit the mobility of either instrument. For this reason, we use ports only to introduce the camera preventing pollution of the tip of the thoracoscope. For easy introduction of either instrument, we dilated the incisions with Hegar dilators. The use of the percutaneous stapling device is characterized by a so-called banana peeling effect if it is used through only one channel. That means that more lung tissue is resected than needed in a tangential way. To prevent this, one might change -shaped excision. A second choice is just to twist the specimen the stapler with the thoracoscope and do a V so one does not have to change channels. With aperipheral lesion and a really totally collapsed lung, that is easy to perform. A difficult aspect of this technique is exposure. For optimal exposure, lung collapse is mandatory and, therefore, the double-lumen endotracheal tube is a necessity. We have not found it necessary to use carbon dioxide insufflation to accomplish lung collapse. Retraction of the collapsed lung often becomes the key to exposure. Also, with the patient secured in the lateral decubitus position, rotation of the table can allow the lung to fall to the appropriate side. CoNCLUSIONS Undefined peripheral pulmonary nodules are a favorable indication for VATS. Centrally located pulmonary nodules of the lower lobes can often be managed easily by only minimally invasive technique, especially if the interlobar fissure extends to the stem of the pulmonary artery. Centrally located pulmonary nodules in the upper lobes may not be appropriate for the VATS approach because of the divergent anatomic arrangement of the upper lobe segmental arteries and bronchioles. REFERE:'\fCES 1 Coltharp WH, Arnold JH, Alford WC, et al. Videothoracoscopy: improved technique and expanded indications. Ann Thorac Surg 1992; 53:776-79 2 Lewis RJ, Caccavale RJ, Sisler GE, Mackenzie JW. One hundred consecutive patients undergoing video-assisted thoracic operations. Ann Thorac Surg 1992; 54:421-26 1574 Video-Assisted Thoracic Surgery of Undefined Pulmonary Nodules (Schwarz eta/)