ENB is used in conjunction with traditional bronchoscopy. Pulmonologist Sandra Gilley, MD, of Pulmonary Associates in Birmingham says they have used this tool for about three years. “We use ENB on select cases that typically involve lesions in the middle of a lung that are harder to reach. We want to be sure we are getting to the correct spot in the bronchial tree, and this technology tells us if we are in the right area,” she says.
ENB uses technology similar to global positioning system (GPS) to navigate a unique set of catheters to lesions deep in the lungs. The procedure is performed through a bronchoscope inserted in the mouth or nose and down the windpipe – there are no surgical incisions. The patient is situated on an electromagnetic board, and the modified CT data with reference points are entered into the system, which transposes the data into the three-dimensional magnetic field occupied by the patient.
A conventional bronchoscope catheter is advanced into the patient’s lung, and the physician advances a smaller catheter with a sensor through the tube. The physician then touches the sensor to the actual anatomical points that correspond with the reference points placed on the planning CT earlier. The system steers the catheters through complex airways beyond the reach of a traditional bronchoscope. Procedural success is greatly influenced by accurate pre-procedure mapping of pathways leading to the target lesion, which in turn is highly dependent on the quality of CT scans provided.
“The software takes a CT scan and constructs a three-dimensional map of the bronchial tube. It identifies where the nodule is and draws a path to it,” Gilley says. “We put sensor probes on the patient during the procedure and it reconstructs the map with the actual bronchial tube. It literally draws a line to follow and shows every turn to make to get to the right spot where we need to take the biopsy.”
ENB, approved by the Food and Drug Administration in 2004, minimizes the need for more invasive surgical procedures to be used to access the lung lesion, which often require an inpatient hospital stay and greater potential for complications, such as pneumothorax. ENB is usually performed in an outpatient center, and most patients go home the day of the procedure, which lasts between 30 minutes to two hours.
“ENB is good for patients who are not good surgical candidates, and it also allows us to tell patients prior to surgery whether the nodule is cancer or just an infection,” Gilley says. “It also gives us the ability to detect lung disease and lung cancers earlier, even before symptoms are evident. That enhances treatment options for patients.”
She adds that the ENB also can be used to place markers to guide radiation therapy or brachytherapy, and she currently offers this option to patients. “These patients won’t have to have surgery. We use the catheters to put beads in the appropriate spots so the oncology radiologist can target the lesions,” Gilley says.
ENB adds an extra level of precision in terms of the diagnostic yield and makes it possible for physicians to reach lesions that conventionally would not be reachable because of a high risk of failure. Gilley says the success rate for diagnosis with this procedure at her center is about 70 percent. The risks of this procedure are the same as traditional bronchoscopy and include possible infection, bleeding and collapsed lung.
“We used ENB on one patient to diagnose a benign nodule as an infection. The procedure saved him from unnecessary surgery,” Gilley says. “We treated him and he had a full recovery. We hope to have many more stories like his.”