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Promising Experience With Robotic-assisted Bronchoscopy for Biopsy of Small Peripheral Pulmonary Nodules

Key findings

  • This paper describes the Ion Endoluminal System for robotic-assisted bronchoscopy and reports the initial experience in an ongoing prospective, multicenter trial for biopsy of small peripheral pulmonary nodules (≥1.0 to ≤3.0 cm)
  • A key feature of the system is its navigation technology—a fiberoptic shape-sensing fiber, embedded throughout a flexible catheter, which provides feedback to the robotic control algorithm to maintain position and orientation
  • Among the first 241 consecutive patients (270 nodules), radial endobronchial ultrasound visualization was achieved in 90% (87% of nodules)
  • Average procedural time was 63 minutes, average navigation time was 10 minutes in the first 10 cases and seven minutes thereafter, and the average airway generation count was seven
  • Eight patients (3.3%) developed asymptomatic post-procedure pneumothorax and two (0.8%) had airway bleeding that was resolved within five minutes of tamponade

Conventional guided flexible bronchoscopes are often suboptimal for biopsy of small peripheral pulmonary nodules (PPNs). Researchers at Massachusetts General Hospital are part of a multicenter study of the Ion Endoluminal System (Intuitive Surgical, Inc.), a robotic-assisted bronchoscopy system that relies on shape-sensing navigation technology, for that indication.

Colleen Keyes, MD, MPH, and Erik Folch, MD, MSc, clinicians in the Division of Pulmonary and Critical Care Medicine at Mass General, and colleagues report early results in The Annals of Thoracic Surgery that demonstrate safety and a favorable complication profile.

Description of Ion

The key features of the system thought to make it useful for biopsy of small PPNs are:

  • The software automatically generates a pathway to the target, which can be modified to extend airways, add pathways, or create additional targets
  • A fiberoptic shape-sensing fiber, embedded throughout a flexible catheter, provides feedback to the robotic control algorithm to correct any tip deflection during tool insertion and biopsy
  • System-specific biopsy needles with radiopaque sheath tips are visible under fluoroscopy
  • A light-emitting probe provides direct 90° visualization
  • The system is compatible with off-the-shelf radial endobronchial ultrasound (rEBUS) probes; the combination of vision with fluoroscopy and rEBUS provides real-time information for refining the distance of the catheter tip to the nodule

Study Methods

The prospective study is enrolling adults with moderate or indeterminate risk of lung cancer who have one or more solid or semisolid PPNs ≥1.0 to ≤3.0 cm beyond subsegmental airways.

The paper reports on the first 241 patients (270 nodules) who underwent biopsy over 12 months by 11 investigators. On average the largest cardinal nodule was 19 mm.

Initial Outcomes

  • Average procedural time (catheter in to catheter out)—63 minutes including wait time for rapid on-site cytology
  • Average navigation time—10 minutes in the first 10 cases, seven minutes thereafter
  • Average airway generation count—Seven (a measure of how far into the respiratory tree the system was deployed)
  • rEBUS visualization achieved—90% at the patient level, 87% at the nodule level
  • Post-procedure pneumothorax—Eight patients (3.3%), asymptomatic in all cases; one patient had a pigtail catheter placed that was removed within 24 hours
  • Airway bleeding—Two patients (0.8%); both cases resolved within five minutes of tamponade

Preliminary Recommendations

This initial clinical experience is reassuring and suggests the system can be considered for elective bronchoscopy of patients with small PPNs. The article discusses best practices for planning, registration, navigation and biopsy.

In this study, about 95% of samples comprised adequate lung tissue and about 65% indicated a malignant condition. Figures on the key outcome measure, diagnostic sensitivity, won't be available until all patients have a confirmatory biopsy or observation over time.

The study is being sponsored by Intuitive Surgical.

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