Electromagnetic navigation bronchoscopy: a comprehensive review
The concept of navigation bronchoscopy is not new, but has evolved over past few decades. Clinicians performing bronchoscopy have utilized various forms of navigation technology ranging from fluoroscopy or computed tomography (CT)-aided guidance in earlier years, now to virtual bronchoscopy and real-time tracking using electromagnetic navigation (EMN) platforms. EMN bronchoscopy relies on a pre-procedural CT of the chest to create a three-dimensional (3D) virtual airway map. This approach is utilized for diagnostic sampling of lung and mediastinal lesions, placement of fiducial markers, or dye marking of the overlying pleura. The diagnostic yield, using this technology, is superior to conventional bronchoscopy techniques and is discussed. The respiratory motion of the airways, lung, and nodule hysteresis creates unique challenges for targeting the lesion. Use of fluoroscopy and radial-probe ultrasound provide meaningful information and additional confirmation with difficult lesions. We continue to evolve in our understanding of how best to utilize the technology, modify diagnostic tools, and improve next-generation platforms. Even so, EMN bronchoscopy has changed the landscape of tissue acquisition for peripheral lung lesions. This review provides important principles and practical aspects of pre-procedure preparation, assessment of airway-lesion relationships, procedural workflow and performance, and points for consideration when contemplating acquisition of an EMN system. The future is in development of intuitive platforms that will allow consistent targeting with higher accuracy so ablation techniques could be performed safely via the endobronchial approach.