Transbronchial lung biopsy (TBLB) obtains tissue from lung lesions by threading sampling tools through the bronchial tree — the airway network — and advancing them to the lesion without a surgical incision. The core challenge is that conventional flexible bronchoscopes can navigate only to the third or fourth generation of bronchial branches, while peripheral lung nodules often sit in the sixth, seventh, or eighth generation airway segments where conventional scopes cannot reach. Robotic bronchoscopy platforms address this reach-and-navigation problem by using thinner, steerable instruments and real-time imaging guidance to access lesions that were previously unreachable without surgery.
The Peripheral Nodule Problem
Peripheral pulmonary nodules — small opacities in the outer lung, often found incidentally on CT scans — are increasingly common as CT screening programs expand. Many nodules are benign, but some represent early-stage lung malignancy. Establishing histological diagnosis is essential for treatment planning, and the clinical question is always: can this lesion be biopsied without surgery?
The diagnostic challenge is anatomical. The bronchial tree branches progressively, each generation narrower than the last:
- Generations 1–2: Trachea and mainstem bronchi — easily reached with any bronchoscope
- Generations 3–4: Lobar and segmental bronchi — reachable with standard flexible bronchoscopes
- Generations 5–7: Subsegmental and smaller airways — beyond standard bronchoscope diameter
- Generations 8+: Terminal and respiratory bronchioles — only reachable with specialized thin instruments
Most peripheral nodules requiring biopsy sit beyond generation 5. Standard flexible bronchoscopes, typically 4–6 mm in outer diameter with limited maneuverability, cannot navigate to these targets.
What Transbronchial Biopsy Involves
A bronchoscope is inserted through the nose or mouth while the patient receives sedation. The physician navigates the scope through the upper airway, vocal cords, trachea, and progressively smaller bronchial branches toward the target lesion.
At the lesion, tissue sampling tools — forceps, needles, or brushes — are passed through the scope’s working channel. Multiple tissue samples are collected.
The procedure takes 30–60 minutes under conscious sedation. Complications include pneumothorax (collapsed lung from air leakage through the puncture site), bleeding, and in rare cases infection. Pneumothorax rates vary by technique and lesion location.
The fundamental navigation challenge is getting the scope tip — or the sampling tool — to the lesion site with confidence that the biopsy is actually sampling the target, not adjacent normal lung.
Navigation Technologies
Several technologies are used to guide transbronchial biopsy to peripheral targets:
Fluoroscopy: Real-time X-ray imaging during biopsy. Fluoroscopy confirms the sampling tool is in the correct region but cannot confirm contact with the specific lesion.
Radial endobronchial ultrasound (r-EBUS): A miniaturized ultrasound probe passed through the bronchoscope working channel. Produces a cross-sectional ultrasound image that can confirm the probe is within or adjacent to the target lesion. r-EBUS confirmation is associated with higher diagnostic yield than fluoroscopy alone.
Electromagnetic navigation bronchoscopy (ENB): Uses an electromagnetic field to track the position of a navigation probe relative to a pre-operative CT-derived 3D airway map. The physician follows a navigation path displayed on screen to reach the target, then locks the extended working channel in position before withdrawing the navigation probe and inserting biopsy tools.
Cone-beam CT (CBCT): Intraoperative CT imaging on a rotating C-arm, providing real-time 3D confirmation of tool position relative to the target. Increases confirmation accuracy but requires specialized hybrid interventional rooms.
Why Robots Extend Reach
Conventional bronchoscope limitations are partly mechanical: the scope body is too rigid to navigate tight turns in small-caliber airways, and the working channel is too narrow to carry biopsy tools once the scope has reached the target site.
Robotic bronchoscopy platforms address these constraints through purpose-built mechanics:
Thinner, more steerable catheter systems — robotic systems use thin, highly articulating sheath-catheter combinations that can navigate more distal airways than conventional scopes.
Continuous navigation guidance — robotic platforms integrate CT-based 3D mapping with continuous position tracking, displaying the instrument’s real-time position within the virtual airway tree.
Stable positioning — robotic arms or shape-locking sheaths maintain the scope’s position at the target during biopsy, reducing movement during sampling.
Software-guided path planning — the physician selects the target lesion on the pre-operative CT, and the system proposes an optimal navigation path through the bronchial tree.
The Duidao Unipath Bronchoscope by Broncus Medical is an example of a navigation bronchoscopy system developed for Chinese clinical use. For context on broader endoscopic robot development, see the endoscopic robots hub.
A study published in Chest (Fielding D, et al., 2019) reported that robotic-assisted bronchoscopy achieved navigation success in peripheral lesions in a high proportion of cases, with acceptable safety, though diagnostic yield varies by lesion characteristics and confirmation method used.
Diagnostic Yield Considerations
“Navigation success” (reaching the planned location) and “diagnostic yield” (obtaining a sample that gives a definitive histological answer) are related but distinct. Even with successful navigation to the lesion site, biopsy yield depends on lesion size, consistency, and the presence of a bronchus sign — a visible airway leading directly into the lesion on CT. Lesions with a bronchus sign typically yield higher diagnostic rates than those without.
Current evidence from published series suggests robotic bronchoscopy improves navigation success compared to conventional approaches, with diagnostic yield numbers in the literature varying by study design and patient population. Adding real-time confirmation (CBCT or r-EBUS) at the biopsy step further improves yield.
Frequently Asked Questions
What is the alternative if transbronchial biopsy fails?
CT-guided percutaneous needle biopsy (through the chest wall) is the most common alternative for peripheral lesions not reachable bronchoscopically. This carries a higher pneumothorax rate than bronchoscopic approaches but higher diagnostic yield for truly peripheral lesions. Surgical wedge resection is the most definitive option when bronchoscopic and percutaneous approaches are nondiagnostic, but carries greater patient burden.
What is the “bronchus sign” and why does it matter?
The bronchus sign is a visible airway leading directly into the target nodule on CT imaging. Its presence predicts that a sampling tool navigated through the airway tree will reach the lesion. Lesions without a bronchus sign sit outside the airway lumen, requiring the sampling tool to traverse lung parenchyma — reducing both navigation accuracy and diagnostic yield.
Is general anesthesia required for robotic bronchoscopy?
Robotic bronchoscopy is typically performed under deep sedation or general anesthesia given the precision required for navigation and the need for patient immobility during the procedure. This contrasts with some conventional bronchoscopy performed under lighter sedation.
How does robotic bronchoscopy relate to surgical navigation?
Robotic bronchoscopy uses similar principles to optical and electromagnetic surgical navigation — pre-operative imaging registered to the patient’s real-time anatomy, with tracked instrument guidance — but applied to the airway tree rather than bony anatomy. The navigation problem is technically distinct because the airway moves with respiration and is not a rigid structure.
Are robotic bronchoscopy platforms available in China?
Robotic and navigation-assisted bronchoscopy is available at selected Chinese tertiary centers, both through imported platforms and through domestic development. NMPA Class III registration is required for clinical use — see How NMPA Class III Medical Device Approval Works in China for the regulatory context.