Purpose : The purpose of this study was to investigate the diagnostic yield and safety of electromagnetic navigation bronchoscopy (ENB) on peripheral lung lesions deemed otherwise unreachable using conventional bronchoscopy in high-risk patients.
Methods : This was a retrospective chart review involving adults (age, 18 y and older) who underwent ENB for pulmonary lesions located at the fourth order of bronchi or beyond, including subpleural lesions, at the University of Chicago Medical Center. Forty-eight patients underwent ENB by 3 different trained operators from January 2006 to September 2008. There was a short period of inactivity when the device was withdrawn from the market. ENB was reserved for use only in lesions at the fourth order of bronchi or beyond, including subpleural lesions, in patients who are considered high risk for other invasive procedures. Pathologic, cytologic, and microbiologic studies were carried out on recovered samples. Postprocedural chest radiographs were obtained on all patients to detect the presence of procedure-associated complications.
Results : ENB led to the diagnosis of 37 of 48 (77%) lesions not amenable to conventional bronchoscopic biopsy in high-risk patients. Of the 37 successful procedures, malignancy was identified in 18 patients (49%). Nonsmall cell lung cancer (NSCLC) was diagnosed 16 times, whereas both small cell lung cancer and carcinoid tumor were diagnosed once. In addition, 4 lesions (11%) were found to be infectious, 1 lesion (3%) was found to be granulomatous (noncaseating), and 1 lesion (3%) was diagnosed as organizing pneumonia. Of the 37 successful diagnoses, 13 lesions (35%) were determined to be nonpathologic, benign lesions. Eleven procedures (22%) were unsuccessful in yielding the correct pathologic diagnosis. Nine of the 11 unsuccessful ENB cases (82%) were found to be malignant, 9 of which were identified as NSCLC. Other than NSCLC, 1 neuroendocrine tumor (9%) and 1 metastatic transitional cell carcinoma of the kidney (9%) were identified by alternative, invasive testing methods. The 2 other lesions unsuccessfully diagnosed by ENB were not malignant. One was determined to be infection (histoplasmosis) and the other was diagnosed as an organizing pneumonia. The most common complication noted by all modalities was pneumothorax. ENB carried a pneumothorax rate of 5 of 49 (10%), 2 of which required chest tube insertion for treatment. In the ENB success group, 4 cases (11%) were complicated by pneumothoraces. In the ENB failure group, 1 case (9%) was complicated by a pneumothorax.
Conclusions : ENB is an effective and low-risk modality for diagnosing pulmonary lesions that are difficult to reach in patients deemed to be at high risk for invasive procedures. Although no clear criteria for the use of ENB currently exist, our study shows that diagnostic sampling can be obtained in 77% of lesions at the fourth order of bronchi or beyond, including subpleural lesions.
Clinical Implications : ENB is an effective, minimally invasive method for the diagnosis of pulmonary nodules previously deemed unreachable by conventional bronchoscopy in high-risk patients and harbors a low complication rate.