Coil spring fiducial markers placed safely using navigation bronchoscopy in inoperable patients allows accurate delivery of CyberKnife stereotactic radiosurgery

Objectives: CyberKnife stereotactic body radiosurgery is a potentially curative option for medically inoperable Stage I lung cancer. Fiducial marker placement in or near the tumor is required. Transthoracic placement using computed tomography guidance has been associated with a high risk of iatrogenic pneumothorax. Electromagnetic navigation bronchoscopy offers a safer method of placing markers; however, previous studies using linear markers have shown at least a 10% dislocation rate. We describe the use of coil-spring fiducial markers placed under moderate sedation in an outpatient bronchoscopy suite. Methods: A total of 52 consecutive nonoperative patients with isolated lung tumors underwent fiducial placement using electromagnetic navigation bronchoscopy. Of the 52 patients, 4 received 17 linear fiducial markers, and 49 patients with 56 tumors received 217 coil-spring fiducial markers. The procedures were considered successful if the fiducial markers had been placed in or near the tumors and had remained in place without migration, allowing radiosurgery without the need for additional fiducial markers. Results: A total of 234 fiducial markers were successfully deployed in 52 patients with 60 tumors (mean diameter 23.7 mm). Of these 60 tumors, 35 (58%) were adjacent to the pleura. At CyberKnife planning, 8 (47%) of 17 linear fiducial markers and 215 (99%) of 217 coil-spring fiducial markers (P = .0001) were still in place. Of the 4 patients with linear fiducial markers, 2 required additional fiducial placements; none of the patients with coil fiducial markers required additional procedures. Three pneumothoraces (5.8%) occurred in peripheral lesions (2 were treated with a pig-tail chest tube and 1 with observation only). Conclusions: Deployment of coil spring fiducial markers using navigation bronchoscopy can safely be performed with the patient under moderate sedation with almost no migration and a 5.8% rate of pneumothorax.