Ann Thorac Surg 2009;87:920-924. doi:10.1016/j.athoracsur.2008.10.020
© 2009 The Society of Thoracic Surgeons
New Technology
Artificial Pneumothorax With Position Adjustment for Computed Tomography-Guided Percutaneous Core Biopsy of Mediastinum Lesions
Zheng-Yu Lin, MD*,
Yin-Guan Li, MD
Department of Radiology, First Affiliated Hospital of Fujian Medical University, Fuzhou, China
Accepted for publication October 14, 2008.
* Address correspondence to Dr Lin, Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, 350005, China (Email: linsinlan{at}yahoo.com.cn).
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Abstract
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Purpose: This study was designed to assess the use of artificial pneumothorax with position adjustment to gain a pleural space approach in computed tomographic-guided core biopsy of mediastinal masses.
Description: Eleven patients with mediastinal lesions who were undergoing percutaneous core biopsies received an artificial pneumothorax with a 22-gauge lumbar puncture needle. Each patient's position was adjusted to place the lesion as high as possible in the thoracic cavity. Air was injected until the lung was displaced from the path of the biopsy needle. After completion of the biopsy, a comparable volume of air was aspirated.
Evaluation: In all patients, satisfactory displacement of the lung from the biopsy site was achieved with the artificial pneuomothorax procedure enabling the target lesion to be reached. No postoperative air leaks requiring tube drainage were encountered.
Conclusions: Artificial pneumothorax with position adjustment is a safe and effective method that provides access for computed tomographic-guided biopsy of mediastinal lesions without the risks of traversing aerated lung tissue and with a relatively low volume of injected air.
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Technology
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Computed tomographic (CT)-guided percutaneous biopsy plays a well-established role in the diagnostic work-up of mediastinal lesions [1–6]. However, the needle path traverses both lung and the visceral pleura during the procedure, which is associated with a risk of pneumothorax [3, 7]. An artificial pneumothorax method with position adjustment was developed in our department that enabled us to reach the mediastinum by means of a pleural space approach. For the first time, we report in detail our clinical experience and assessment of the use of this method.
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Technique
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Subjects and Surgical Preparation
This study was approved by the Ethics Committee of our hospital, and all patients enrolled in the study provided written informed consent. Eleven consecutive patients (7 men, 4 women; age range, 17 to 75 years; mean age, 45.5 years) who had mediastinal masses underwent CT-guided artificial pneumothorax with position adjustment percutaneous core biopsy at our institution from January 2006 through March 2008. All participating patients were not candidates for alternate methods for avoiding lung aeration, such as the saline window technique, and had no history of ipsilateral thoracic surgery. Contrast material enhanced CT findings were available for evaluation prior to biopsy in all cases (Figs 1a,
2a,
3a). One day before the operation, coagulation measurements and platelet counts were obtained from all patients to exclude bleeding diathesis.
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Fig 1. Axial computed tomographic images from a 36-year-old man with an anterior mediastinal thymoma. (a) Mass in the anterior mediastinum (white arrow). (b) Passage of a 22-gauge pediatric lumbar puncture needle (black arrow) through the parietal pleura into the right pleural space. (c) A very small pneumothorax (black arrow) produced by injection of 20 mL of air. (d) The mass remained covered by aerated lung after injection of 400 mL of air with the patient in his original position. (e) After the patient's position was adjusted, the lung was displaced from the target lesion site, enabling a core biopsy needle to avoid the aerated lung and gain access to the lesion. (f) Most of the air was aspirated from the pleural space after collection of the biopsy sample, leaving a small residual right pneumothorax (white arrows).
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Fig 2. Axial computed tomographic images from a 72-year-old man with an adenocarcinoma in the aortopulmonary window. (a) Mass in the aortopulmonary window. (b) After introduction of 1,000 mL of air, the mass was still covered by the aerated lung. (c) After the patient was adjusted to the lateral decubitus position, the aerated lung was displaced from the path of the biopsy needle and the needle (arrow) was placed anterior to the mass.
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Fig 3. Axial computed tomographic images from a 56-year-old man with right paratracheal tuberculosis. (a) A mass with irregular necrosis (white arrow) in the right paratracheal region. (b, c) After introduction of 500 mL of air into the right pleural space, the aerated lung was displaced from the path of the biopsy needle and the needle (white arrow) was placed in the mass. (d) A small, residual right pneumothorax and subcutaneous emphysema of right chest wall (black arrow) after most of the air was aspirated from the pleural space after collection of the biopsy.
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Operation
Patients received conscious sedation with continuous blood pressure and oxygen saturation monitoring. The thoracic skin at the surgical entry site was sterilized with topical Betadine solution (Likang Co Ltd, Shanghai, China) and anesthetized with local injections of 1% lidocaine hydrochloride (Wuxi Pharmaceutical, Wuxi, China). Under CT guidance using a 16-slice CT scanner (Toshiba Aquilion M16; Toshiba, Tochigi, Japan), a 22-gauge pediatric lumbar puncture needle with a 30°-beveled end was pushed into the chest wall to gain percutaneous access to the pleural space. The needle was advanced to the outer margin of the parietal pleura (Fig 1b). When the needle reached the pleura, the stylet was removed and replaced with a segment of transparent rubber tube. A small volume of sterile saline was injected into the tube and a water column segment was formed. As the needle tip passed through the parietal pleura, the water column was aspirated into the pleural space for the presence of the negative pressure. A very small pneumothorax visible by CT was created by infusion of 20 mL of air through the needle (Fig 1c). On confirmation of the intrapleural position of needle tip, 200 mL of air was administered to expand the artificial pneumothorax (Figs 1d and 2b). Each patient's position was then adjusted to make the lesion as high as possible in the thoracic cavity, so that the target could be reached through the air-containing pleural space with minimal air injection. Additional air was injected until the lung was displaced from the trajectory of the biopsy needle path. Repeat CT imaging was used to guide an 18-gauge semi-automatic core biopsy needle (Dr Japan Co Ltd, Tokyo, Japan) into the lesion.
All patients had at least 1 core tissue biopsy (range, 1 to 4; mean, 1.8) (Figs 1e, 2c, 3b, 3c). When multiple specimens were collected, the same needle was used to collect them. After the biopsies were completed, a volume of air similar to that which had been inserted was aspirated from the pleural space through the lumbar puncture needle (Figs 1f and 3d). A few minutes after completion of the procedure, each patient was subjected to a CT scan to screen for early complications.
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Clinical Experience
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The age and gender of the patients, the mediastinal lesion sites, and the CT-guided biopsy derived diagnoses are shown in Table 1. The biopsied lesions ranged from 2.2 to 7.7 cm (mean, 3.6 cm) in maximum diameter. Satisfactory displacement of the lung from the biopsy site was achieved by the creation of an artificial pneuomothorax in all patients. The mean time required to establish the artificial pneumothorax with the positional adjustment was 16 min (range, 9 to 33 min). The mean air volume infused was 680 mL (range, 400 to 1,400 mL).
The target lesion was successfully sampled in all patients (11 of 11). A conclusive diagnosis was obtained in 10 of 11 biopsies. One patient (no. 8, Table 1) with an inconclusive diagnosis (celiothelioma or thymoma) underwent surgical biopsy; the result was Hodgkin's lymphoma (nodular sclerosis type).
The procedure was well tolerated by all patients as evidenced by maintenance of oxygen saturation greater than 90%, and no abnormal fluctuations in blood pressure. None of the patients required postoperative tube drainage of an air leak. After the aspiration of the injected air, a small amount of air remained in the pleural space (less than 3%) and subcutaneous tissue in all 11 patients. A small amount of reactive pleural effusion was found in 4 patients (4 of 11), but did not lead to any troublesome symptoms or clinical sequelae.
One patient who underwent anterior mediastinum biopsy had a small hematoma develop adjacent to the lesion. The patient remained clinically stable and was subjected to a repeat CT 3 hours after the operation. The hematoma did not increase in size, and the patient was discharged after 4 hours of observation.
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Comment
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We observed satisfactory displacement of lung tissue from the biopsy site with the artificial pneuomothorax procedure. None of the patients suffered serious postoperative air leaks, visceral pleura injuries, pneumothorax, or pulmonary bleeding. Only very small amounts of air remained postoperatively in the pleural space, subcutaneous tissue, and mediastinum.
Some large anterior mediastinal masses that reach the anterior chest wall can be reached by the parasternal approach without traversing lung tissue [8]. However, the needle may produce injuries as it passes through the thorax. Pneumothorax is the most common serious complication after percutaneous transthoracic needle biopsy. Several nontranspulmonary approaches have been proposed to avoid this complication, including a transsternel approach and a saline window technique. However, none of these methods is appropriate for every patient [1, 2, 7, 8]. A particularly versatile method is the "protective pneumothorax" approach in which air is injected into the pleural space in a controlled manner, such that it displaces the lung from the anticipated trajectory of the biopsy needle path [2, 4, 5, 9]. The first case in which a "protective pneumothorax" was used to prepare for a percutaneous needle biopsy of a mediastinal mass was described by Bressler and Kirkham [2].
The diagnostic accuracy of aspiration biopsy with routine cytology for lymphoma, thymoma, germ cell tumors, and neurogenic tumors is poor [10]. It is sometimes necessary to use a large bore biopsy needle and collect multiple samples to obtain an accurate diagnosis. In such cases the pleural space approach can provide adequate space to adjust the needle angle and conduct repeat punctures. Of the present cohort of 11 patients, 6 had multiple core tissue biopsies (2 to 4 times), and none of them suffered a visceral pleura injury or postoperative air leak. With CT-guided core-needle biopsy, we observed a diagnostic accuracy of 90.9% (10 of 11) in this study. One patient was misdiagnosed histopathologically with a fibrous nodular sclerosis type of Hodgkin's lymphoma. The surgical biopsy diagnosis was also difficult in this case.
Redundant air in the pleural space can impair respiratory function and result in problems such as dyspnea, especially in patients with poor pulmonary function. Therefore, it is preferable to minimize the amount of air that is injected when generating an artificial pneumothorax. In our department, a method of adjusting the patient's position has been developed to minimize the amount of air that is injected. There are no prior descriptions of such a method in the literature. With prior methods, injected air has a tendency to pool in the superior region of the pleural space. However the anatomical location of the injected air pocket can be controlled by altering the patient's position. We demonstrated that this method enables the surgeon to inject a smaller volume of air into the patient's thorax. In our study, the mean volume of injected air was 680 mL (range, 400 mL to 1,400 mL), which is notably less than the 1,000 mL mean air injection volume reported by Scalzetti [9]. Furthermore, position adjustment can increase the scope of biopsy. We were able to access lesions throughout the mediastinum, including two cases of lesions in the aortopulmonary window. Using this technique, we achieved a more flexible puncture path using less air, which is particularly important for masses in the aortopulmonary window and pulmonary hilum.
Five patients in this study experienced minor complications. The most common complication was the presence of small amounts of reactive pleural effusion (4 of 11), followed by development of a small mediastinal hematoma (1 of 11). The reactive pleural effusion incidents that resulted from artificial pneumothorax were generally absorbed by 24 hours after the procedure, and no subsequent clinical sequelae developed. Mediastinal hematomas can also occur with other mediastinal biopsy approaches [2].
Lysis of pleural adhesions should not be attempted percutaneously in cases where adhesions prevent adequate lung displacement due to the risk of causing bleeding and of tearing the pleura. In addition, iatrogenic pneumothorax is a potential complication that can result from injury to the visceral pleura during creation of artificial pneumothorax and aspiration of air from the pleural space. The incidence of this risk can be reduced by using a fine needle. In our study, we used a 22-gauge pediatric lumbar puncture needle to obtain percutaneous access to the pleural space. There was no intrusion of the visceral pleura, and the procedure was safe and convenient in all cases.
It should be mentioned that the method has the disadvantage of increasing patients' radiation load and operative time. In addition, the method is counter-indicated in some cases, such as in patients suffering from severe respiratory insufficiency. This study has limitations related to the fact that there had only been 11 patients subjected to this method in our center at the time this report was written. Because of this, no pulmonary hilar lesion biopsy cases were included herein. More experience with the technique is needed before the full extent of the clinical benefits can be known.
In conclusion, the present study indicates that artificial pneumothorax with position adjustment is a safe and effective method. The method provided access for CT-guided biopsy of mediastinum lesions without traversing aerated lung and decreased the volume of injected air. Importantly, the amount of time by which the procedure was extended was modest. A larger group of cases should be examined to confirm the present findings.
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Disclosures and Freedom of Investigation
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No financial support was received for this study. The authors had full control of the design of the study, the methods used, the outcome variables, data analysis, and the written report.
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Footnotes
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Disclaimer The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.
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References
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- Bressler EL, Kirkham JA. Mediastinal masses: alternative approaches to CT-guided needle biopsy Radiology 1994;191:391-394.[Abstract/Free Full Text]
- Protopapas Z, Westcott JL. Transthoracic hilar and mediastinal biopsy Radiol Clin North Am 2000;38:281-291.[Medline]
- Zwischenberger JB, Savage C, Alpard SK, Anderson CM, Marroquin S, Goodacre BW. Mediastinal transthoracic needle and core lymph node biopsy: should it replace mediastinoscopy? Chest 2002;121:1165-1170.[Abstract/Free Full Text]
- Wein BB, Dickgreber NJ, Gunther RW. Protective pneumothorax in CT-guided mediastinal puncture Rofo 1997;166:346-350.[Medline]
- Klose KC. CT-guided large-bore biopsy: extrapleural injection of saline for safe transpleural access to pulmonary lesions Cardiovasc Intervent Radiol 1993;16:259-261.[Medline]
- Haramati LB, Austin JH. Complications after CT-guided needle biopsy through aerated versus nonaerated lung Radiology 1991;181:778.[Abstract/Free Full Text]
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- Weisbrod GL. Percutaneous fine-needle aspiration biopsy of the mediastinum Clin Chest Med 1987;8:27-41.[Medline]
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Ann. Thorac. Surg.,
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