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Ann Thorac Surg 1998;66:1170-1173
© 1998 The Society of Thoracic Surgeons

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Original articles: general thoracic

Videothoracoscopic lung biopsy in diffuse infiltrative lung diseases: a 5-year surgical experience

^a Department of Thoracic and Vascular Surgery, Avicenne Hospital, Bobigny, France
^b Department of Pulmonary Medicine, Avicenne Hospital, Bobigny, France

Accepted for publication May 3, 1998.

Address reprint requests to Dr Zegdi, Department of Thoracic and Cardiovascular Surgery, Hôpital Broussais, 96 rue Didot, 75014 Paris, France

Abstract

Background. To establish an accurate diagnosis of diffuse infiltrative lung disease, a surgical lung biopsy may be required. We report our experience with videothoracoscopic lung biopsy over a period of 5 years.

Methods. From March 1992 through December 1996, videothoracoscopic lung biopsy was performed in 64 patients (17 were women [26.5%]; age, 50.5 ± 13 years) with a diagnosis of diffuse infiltrative lung disease of an unknown cause. All patients except one received general anesthesia. Single lung ventilation was used in 61 patients. All lung biopsies were obtained with an endoscopic stapler.

Results. Single lung biopsies were performed in 39 patients (61%), two biopsies in 23 patients (36%), and three biopsies in 2 patients. Minithoracotomies were necessary in 10 patients (15.6%) owing to an iatrogenic pulmonary wound (1 patient), extensive pleural adhesions (6 patients), and a stiff lung (3 patients). Postoperative complications were rare and included five discrete pneumothoraces (7.8%), all resolving spontaneously, one prolonged air leak (1.6%), and one hemothorax requiring reoperation. Three preoperatively debilitated patients died (4.7%), 2 with progression of respiratory failure and 1 owing to septic shock. Average chest tube duration was 2.4 ± 2 days and average hospital stay was 4.6 ± 2.5 days. Lung biopsy contributed to the diagnosis in 59 patients (92%).

Conclusions. Videothoracoscopic lung biopsy using an endoscopic stapler is a safe and effective procedure in most cases and should be performed by trained thoracic surgeons.

Lung biopsy may be required for the diagnosis of patients with diffuse infiltrative lung diseases (ILD) [1, 2]. In patients for whom transbronchial biopsy is contraindicated or has failed (eg, inadequate tissue sample or nonspecific inflammation in the histologic examination), a surgical lung biopsy is often indicated [3]. Open lung biopsy has long been considered the gold standard [3, 4], but it remains an aggressive approach. Videothoracoscopic lung biopsy (VTLB) has been reported to be a less invasive alternative method and as effective as the open procedure [5–11].

In this article we describe our 5-year experience with videothoracoscopic lung biopsy performed in patients with diffuse ILD.

Patients and methods

From March 1992 through December 1996, 64 consecutive patients with a diagnosis of diffuse ILD of unknown cause despite extensive evaluation were referred to our department for lung biopsy. All patients received preoperative chest computed tomographic scan. One to three biopsies (from at least two different lobes) were performed on the most radiographically involved lung.

Our patient population consisted of 17 women (26.5%) and 47 men (73.5%). The mean age was 50.5 ± 13 years; 47 patients were less than 60 years and 5 were older than 70 years. None required home oxygen. Six patients were positive for the human immunodeficiency virus. Three patients were preoperatively admitted to an intensive care unit because of acute respiratory failure; tracheal intubation was necessary in only 1 patient.

All videothoracoscopic lung biopsies were performed under general anesthesia, except in 1 patient for whom intubation was avoided because of poor general condition. A double-lumen endotracheal tube was used for single-lung ventilation. However, the procedure was performed using a single-lumen endotracheal tube in 2 patients: one with acute lung failure and another who had experienced a hypoxic episode during anesthetic induction.

Patients were then placed in a lateral decubitus position and prepared and draped for possible axillary thoracotomy. A three-trocar approach was used in all patients. The thoracoscope was inserted through the lower port (eighth intercostal space, midaxillary line) and a lung grasper and endoscopic stapler were introduced into the thoracic cavity through the two superior ports (fifth intercostal space, anterior and posterior axillary lines). After careful inspection of the pleural cavity and the lung surface, the biopsy site was chosen based on chest computed tomographic abnormalities and on intraoperative findings. The lung was gently grasped and a V-shaped wedge resection was taken using an Endo-GIA 30 stapler (US Surgical Corp, Norwalk, CT) with 3.5-mm staples. When a single-lumen endotracheal tube was used, the patients were ventilated with reduced tidal volume throughout the procedure. Ventilation was briefly stopped during lung stapling. The specimens were removed through an ipsilateral port and sent for adequate microscopic and microbiologic analysis.

At the completion of the procedure, the lung was reinflated and all suture lines were checked for hemostasis and aerostasis. Two chest tubes (24F) were inserted through the anterior and inferior incisions and placed under direct vision. The remaining incision was closed with simple sutures. The chest tubes were connected to a Pleur-evac (Deknatel, Fall River, MA) drainage system and placed to suction. All chest tubes were removed when the drainage was minimal, the lung was fully reexpanded, and any air leak had resolved. The patient was usually discharged within 2 days.

Results are expressed as mean plus or minus standard deviation. A Mann–Whitney test was used for comparisons between quantitative variables. A p value of less than 0.05 was considered significant.

Results

The right side was operated on in 44 patients (69%). A single lung biopsy was performed in 39 patients (61%), two biopsies in 23 patients (36%), and three biopsies in 2 patients. The locations of biopsy sites were: left upper lobe, 12 patients (13.1%); left lower lobe, 18 patients (19.8%); right upper lobe, 15 patients (16.5%); right lower lobe, 36 patients (39.6%), and middle lobe, 10 patients (11%).

A 4- to 5-cm minithoracotomy (usually an axillary thoracotomy) was necessary in 10 patients (15.6%) because of a pulmonary laceration resulting from a trocar insertion, extensive pleural adhesions in 6 patients (9.4%), and a stiff lung that made endoscopic stapler use difficult in 3 patients (4.7%).

In the nonthoracotomy group, Endo-GIA 30 cartridge consumption was 4.3 ± 1.9 per patient, or 3.4 ± 1.1 per biopsy.

Postoperative complications were rare. Five patients (4 in the thoracoscopic and 1 in the thoracotomy group) experienced small apical pneumothoraces, all of which resolved spontaneously. One hemothorax occurred postoperatively in a patient whose lung biopsy had required a conversion to minithoracotomy. At reexploration the minithoracotomy was extended, but no cause of bleeding was found. One patient (1.6%) who was ventilated preoperatively with a high positive end-expiratory pressure experienced a prolonged air leak (more than 5 days).

Three patients (4.7%) died postoperatively. One patient presented with acute lung failure which required emergent endotracheal intubation. She was diagnosed with end-stage pulmonary fibrosis and died 12 days postoperatively of refractory hypoxemia. One human immunodeficiency virus–positive patient was admitted to an intensive care unit for severe hypoxemic interstitial pneumonia. Despite empiric therapy against Pneumocystis carinii and serially negative bronchoalveolar lavages, his pulmonary status deteriorated. Surgical lung biopsy revealed P carinii and cytomegalovirus infection. The patient ultimately died 14 days postoperatively. The third patient, who had chronic lymphoid leukemia, was diagnosed with interstitial fibrosis and died postoperatively from septic shock.

The mean operating time was 67 ± 35 minutes and the mean duration of chest tube drainage was 2.5 ± 2 days (range, 1 to 12 days). The mean hospital stay was 4.6 ± 2.5 days (range, 2 to 14 days). Duration of chest tube drainage and hospital stay did not differ among patients who experienced a pneumothorax and those with an uneventful postoperative course (3.5 ± 1.7 days and 6.2 ± 2.3 days versus 2.4 ± 2.2 and 4.5 ± 2.5 days, respectively not significant [NS]). Conversion to thoracotomy was associated with a longer operative procedure (105 ± 16 minutes in the minithoracotomy group versus 60 ± 4 minutes in the thoracoscopic group; p < 0.001) but did not lengthen the chest tube duration (2.4 ± 0.4 days versus 2.4 ± 0.3 days; NS) or the hospital stay (4.8 ± 0.8 days versus 4.6 ± 0.3 days; NS).

Taking clinical findings into account, a histologic diagnosis was obtained in 59 patients (92%):

Idiopathic pulmonary fibrosis 19 Hypersensitivity pneumonitis 7 Sarcoidosis 7 Infection 5 Pneumoconioses 5 Bronchiolitis obliterans with organizing pneumonia 5 Lymphoma 4 Kaposi’s sarcoma 1 Bronchiolar alveolar carcinoma 1 Langerhans cell pulmonary histiocytosis 1 Wegener’s granulomatosis 1 Hyalinized granulomas 1 Hypereosinophilic syndrome 1 Diffuse alveolar damage 1

Lung biopsy was normal in 1 patient who had been treated anteriorly for a myeloma; nevertheless, a pulmonary recurrence and an opportunistic infection could have been excluded. In 2 patients a discrete bronchiolitis was present only on lung specimens and was subsequently attributed to their smoking. Finally, histologic findings in 2 patients were not specific and biopsies were considered to be noncontributory. Of the five nondiagnostic lung biopsies, four had been performed in the videothoracoscopic group and three in human immunodeficiency virus–positive patients.

Comment

Because of the multiple causes of diffuse ILD (more than 200 causes have been reported), accurate diagnosis remains a clinical challenge. When the cause of the disease remains known despite careful clinical, radiologic, and serologic evaluation, lung biopsy may be indicated [1–3]. Because it is less invasive, transbronchial biopsy is usually performed first. If it is contraindicated or nondiagnostic, surgical lung biopsy is often the next step.

Open lung biopsy has long been regarded as the gold standard, achieving an accurate diagnosis in more than 90% of patients with diffuse ILD [1]. Its diagnostic yield is superior to transbronchial biopsy [3, 4]. Establishing a precise diagnosis is clinically important, as it will provide an appropriate therapeutic strategy. In 54% to 73% of patients [8, 12], surgical lung biopsy results changed the therapeutic treatment of patients with diffuse ILD. Finally, lung biopsy results also have prognostic value [13]. Most surgeons performed open lung biopsy through a small (usually anterior) thoracotomy. The mini-incision, although more aesthetic, has lower postoperative morbidity than posterolateral thoracotomy [14]. However, its main disadvantage is reduced exposure, thus limiting the choice of biopsy site.

With the recent evolution of videotechnology, videothoracoscopic surgery has proved to be a useful tool for diagnosis or treatment of many intrathoracic disorders [15, 16]. Pain and lung dysfunction are also reduced in the postoperative period [17, 18]. This point is particularly important because most patients with diffuse ILD have significantly impaired preoperative pulmonary function tests. In addition, videothoracoscopy offers excellent visualization of the pleural cavity with greater intrathoracic accessibility to the surgeon compared with the minithoracotomy.

Lung biopsies currently represent 2% to 13.7% of video-assisted thoracic procedures [19–21]. Several lung biopsy methods are available. Some authors [22, 23] performed a forceps biopsy. These samples, which are often crushed, are small in size and need to be numerous (up to 10 biopsies in the series of Dijkman and associates [22]), which may increase the risk of prolonged postoperative air leak. Hemostasis is easily achieved, usually by electrocoagulation. Forceps biopsy involves only the superficial (subpleural) lung parenchyma, which may explain a lower diagnostic yield in some diffuse infiltrative lung diseases such as bronchiolitis obliterans with organizing pneumonia, histiocytosis, and vasculitis [24]. Stapled wedge resection probably represents the most frequently performed lung biopsy method. It is easy and fast and is associated with a lower risk of prolonged postoperative air leak (1.6% in our series), which explains its success among thoracic surgeons. However, its high cost constitutes a major drawback. Finally, endoscopic stapler dysfunction requiring conversion to thoracotomy has rarely been reported [19]. Videothoracoscopic lung biopsies have also been performed with the neodymium:yttrium-aluminum garnet laser [25], particularly in the case of a stiff lung which prevents proper and safe use of endoscopic staplers owing to the risk of lung tearing. Because of its high cost, this method has been limited to a few centers.

Performing a VTLB is not always without difficulty. An unsatisfying collapse of the nonventilated lung is frequently seen and may be due to a poorly positioned endotracheal tube, the presence of extensive pleural adhesions, or a noncompliant lung. Proper placement of the endotracheal tube, removal of pleural adhesions, and manipulation of the lung with endoscopic instruments all allow the procedure to be completed usually without conversion to a minithoracotomy. We have not experimented with intrapleural CO₂ insufflation for lung collapse [15] because of its potential for hemodynamic instability and gaseous embolism. The presence and extent of pleural adhesions cannot be reliably predicted preoperatively. Extensive and thick pleural adhesions have been observed in 11 patients [17%] from our series. Their presence is associated with an increased risk of iatrogenic lung injury during trocar insertion or during dissection with an overall longer operative procedure. A stiff lung may be inappropriate for endoscopically stapled lung resection because it may be technically difficult or unsafe to bring the lung parenchyma into the two jaws of the Endo-GIA 30. In this particular circumstance, videothoracoscopic lung biopsies may be obtained by using either a thicker endoscopic stapler or the forceps technique, but with the risks mentioned previously. Because thicker endoscopic staplers were not available to us, we elected to convert to a minithoracotomy in 3 patients with stiff lung to achieve stapled lung resection.

Conversion to a minithoracotomy has been rarely reported in the VTLB series; its incidence ranges from 0% to 5.3% [5–11]. In our surgical series, a minithoracotomy was performed in 10 patients (15.6%) (one lung injury, three stiff lungs, and extensive pleural adhesions). Because of this, VTLB should be always performed in an operating suite by trained thoracic surgeons.

Published mortality rates have varied from 0.3% to 70% in open lung biopsy series [1, 26] with the highest rates seen in immunodeficient patients or in acute respiratory failure. Among our 3 patients (4.7%) who died postoperatively, 2 were immunodeficient and 1 was ventilator dependent before the operation. We share Krasna and associates’ [10] recommendation that ventilator-dependent patients should not undergo the videothoracoscopic approach. In fact, the procedure is technically more difficult and no postoperative benefits have been seen in this subset of patients with diffuse ILD.

Few studies comparing VTLB and open lung biopsy have been reported to date [5–8] (Table 1). Concerning all previously published retrospective studies, some advantages have been noted with the videothoracoscopic approach: a lower rate of postoperative complications, a shorter hospital stay, and a shortened convalescence period. The diagnostic yield, ranging from 94% to 100%, seems to be unaffected. However, prospective, randomized clinical studies are warranted to confirm these data and to define the clinical role of VTLB in diffuse ILD.

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