Trans-parenchymal nodule access (TPNA) - Real-time image-guided approach to pulmonary nodules

BACKGROUND: Currently, pulmonary nodules (PN) are accessed by Transthoracic Needle Aspiration (TTNA) or Transbronchial Needle Aspiration (TBNA). There is a clinical need for improvement of bronchoscopic access to small (<10mm) intraparenchymal PNs such that the high yield of TTNA and the safety of TBNA is achieved. OBJECTIVE: To assess the safety and yield of Trans-Parenchymal Nodule Access (TPNA). METHODS: In a healthy canine model, multiple 0.25cc calcium hydroxylapatite injections were implanted to represent ≤8mm diameter PNs in the upper and lower lobes. CT scans were acquired and plans were generated to prescribe a vessel-free, straight-line path from a central airway location directly to the target using an image guidance system (LungPoint®). Access through the airway wall was initiated with a TBNA needle followed by balloon dilation and sheath insertion. Advancement of the sheath was guided by overlaying CT-defined targets and tunnels onto the live fluoroscopy images using the system. The sheath enabled target sampling with 2.0mm biopsy forceps through the lumen. RESULTS: In 10 canines, 31 targets averaging 34mm (21mm – 50mm) from the airway wall and 7.6mm (0.1mm – 21mm) from the pleura, were accessed via TPNA and sampled. Sampling results indicated a yield of 90.4% with no pneumothoraces and minimal bleeding (<2ml). CONCLUSIONS: These canine studies demonstrate that TPNA has the potential to achieve the high yield of TTNA with the low complication profile associated with TBNA.