Feb 192012

Traditional bronchoscopy with transbronchial biopsy (TBBx) has only a 34% sensitivity at diagnosing peripheral pulmonary nodules < 2 cm in size. Transthoracic needle aspiration (TTNA)'s superior sensitivity of 90% for diagnosing peripheral lesions makes it the standard of care for peripheral lesions, but TTNA carries a considerable risk for pneumothorax. A huge proportion of patients experience pneumothorax after transthoracic needle biopsy in clinical studies, and a 2011 population study suggested at least a 15% risk in real world community practice in the U.S., with about 1 in 14 requiring a chest tube. Often such pneumothoraces are small, sometimes even asymptomatic, but it's nevertheless an inconvenient and uncomfortable complication to inflict on a patient, especially when chasing a diagnosis of an incidentally discovered nodule that's likely benign (or else why would you be biopsying it, rather than proceeding to thoracotomy and resection?).

Technology companies long ago sensed the market opportunity here, and have created navigational bronchoscopy tools that can extend the reach of traditional bronchoscopy, allowing low-risk biopsy attempts of peripheral lesions. Electromagnetic navigational bronchoscopy has been shown in isolated studies (including a randomized trial) to improve the sensitivity of bronchoscopy, but overall results have been mixed so far, and large insurers still consider EMNB an experimental technology that they won't pay for.

Virtual bronchoscopy is a different technology that uses CT scanning alone to make a map of the bronchial tree, which a physician can then view on a screen while navigating the real bronchial tree with an ultrathin bronchoscope. Virtual bronchoscopy differs from EMNB in that it doesn't rely on realtime positional signaling from sensors around the patient. Until this trial in Thorax, there have been virtually no published studies on virtual bronchoscopy's performance.

Takashi Ishida et al randomized 199 patients with peripheral lesions < 3 cm to undergo a biopsy attempt using either virtual bronchoscopy-assisted endobronchial ultrasound (VB+EBUS) or EBUS alone. The study took place at multiple centers in Japan.

Results: A pathological diagnosis was achieved in 80% of patients in the VB+EBUS group, but only 67% of those in the EBUS alone group (p=0.032). There was one small pneumothorax in the EBUS alone group.

For those patients undiagnosed by bronchoscopy, the gold standard for final diagnosis was made either by other additional procedures (such as transthoracic needle biopsy) or 2-year follow-up. There were no obvious biases and appeared to be good randomization (e.g., both arms had an ~80% rate of malignancy, with infections accounting for most of the rest).

How much would virtual bronchoscopy cost? Hard to say without calling the company. The electromagnetic bronchoscopic navigational system (such as those produced by superDimension) has a list price of about $150,000, with additional expenses of $700-1000 per-procedure for each proprietary single use catheter. Virtual bronchoscopy has the advantage of not requiring these expensive catheters. Broncus Technologies produces the LungPoint virtual bronchoscopy system, which is mainly promoted in Japan, but they've partnered with a firm to distribute LungPoint in the U.S. No word online as to how much the system will cost, or whether insurers will be paying physicians per procedure over and above the standard fees for bronchoscopy and EBUS.

As with any new procedural technology, you have to assume there's an experience effect baked into these fantastic yields. What was their yield on their first 30 procedures? How many did they do per week to maintain their proficiency, and what would be the yield for someone just doing a few of them per month in the community? These are the skeptical questions that haunt insurance company bureaucrats' minds as they consider whether to offer extra physician payments for a new technology such as virtual bronchoscopy.

Ishida T et al. Virtual bronchoscopic navigation combined with endobronchial ultrasound to diagnose small peripheral pulmonary lesions: a randomised trial. Thorax 2011;66:1072-1077.

Navigational Bronchoscopy. Overview of Technology and Practical Considerations—New Current Procedural Terminology Codes Effective 2010. CHEST 2010;137:450-454.

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Virtual bronchoscopy diagnosed 80% of peripheral lung nodules (RCT, Thorax)