Transthoracic endosonography for the intraoperative localization of lung nodules

Transthoracic ultrasonography has been advocated for the localization of lung nodules during video-assisted thoracoscopic surgery (VATS) for nonperipheral nodules.

Video-assisted thoracoscopic surgery for lung nodules was performed in 54 consecutive patients. Preoperative computed tomography (CT) diagnosed 65 lesions. Positron emission tomography (PET) identified 2 lesions not revealed by CT. All nodules were judged whether visible and/or palpable. Diameter and distance of the nodule from the anterior, lateral, and posterior chest wall were measured on CT scan and served in a discriminant analysis to predict which nodule would be neither visible nor palpable. The deflectable multifrequency (7.5 to 10 MHz) endosonography probe was used to identify the nonvisible and nonpalpable nodules.

Resected nodules were 69; 67 diagnosed preoperatively, and 2 intraoperatively by ultrasonography. At VATS exploration 16 of 65 (25%) of the CT diagnosed nodules were nonvisible and nonpalpable. The discriminant analysis failed to predict correctly whether nodules would be visible and/or palpable in 33% because of surrounding severe emphysema, proximity to a fissure, or to the hylum. The endosonography identified 15 out of 16 of the nonvisible and nonpalpable nodules, thus conversion to thoracotomy was necessary for one nodule. The combination of video, palpatory, and endosonographic inspections had 98% sensitivity and 100% specificity in localizing the nodules.

Intraoperative transthoracic ultrasonography is useful to guide VATS resection of lung nodules. It is a bedside tool, not requiring planning and coordination with the interventional radiology suite, thus you use it if you need it. It has no related morbidity, and may also have a role in revealing lesions occult at preoperative work-up.