Robotic-assisted bronchoscopy with cone-beam CT for pulmonary nodule biopsy

Pulmonologists at the Harron Lung Center have introduced a new approach to pulmonary nodule diagnosis that combines the innovative technologies of robotic-assisted bronchoscopy and cone-beam computed tomography (CBCT).

The goal when attempting to diagnose the cause of pulmonary nodules definitively is finding a safe, consistent, and high-yield biopsy approach. Achieving this goal has been greatly augmented by the advent of electromagnetic navigational bronchoscopy (ENB), and more recently, robotic-assisted bronchoscopy and intraprocedural cone-beam computed tomography (CBCT).

Despite the contribution of these innovations to yield and diagnostic accuracy, the diagnosis of suspicious peripheral pulmonary nodules remains a principal challenge for interventional pulmonologists.

Reaching the nodule has always been an obstacle for endobronchial approaches, particularly nodules in the peripheral lung, where the progressive diminishment and angulation of the branching bronchi impede the advancing bronchoscope.

Other practical issues include determining the risk value of individual nodules — the current guidelines define nodules as an intermediate risk if a 5% to 70% pre-test probability of lung cancer exists — and evaluating the comparative efficacy (i.e., accuracy, yield, safety) of the available technologies.

The next frontier: Enhanced robotic-assisted bronchoscopy with cone beam CT guidance

Recently, pulmonologists at Penn Medicine have introduced combined robotic-assisted endoscopy and cone-beam computed tomography (CBCT) to improve upon the intra-procedural reach, accuracy, yield, and safety of bronchoscopy for pulmonary nodule biopsies.

Led by interventional pulmonologist David DiBardino, MD, at the Harron Lung Center, this effort builds upon the proven efficacy of the technologies as individual modalities. In a recent retrospective cohort study, Dr. DiBardino and colleagues found an adjusted diagnostic yield of 85% for CBCT when combined with ultra-thin bronchoscopy and radial endobronchial ultrasound (R-EBUS).

In the few in human studies of robotic-assisted bronchoscopy, diagnostic yields have ranged from 69% to 82%.

Combining CBCT and robotic bronchoscopy is novel and may provide added benefits compared with using either technology in isolation. CBCT employs a compact CT system with a moving C-arm that provides real-time information about the instrument and target lesion location during bronchoscopy.

Once obtained, CBCT imaging can be reformatted to provide views for each anatomic plane. Target lesions can then be outlined and overlaid on live fluoroscopic imaging to render a target for navigation and sampling.

The robotic bronchoscope comprises an outer sheath and inner scope containing a working channel housed in a unit that manipulates the bronchoscope’s insertion, retraction, and articulation. These movements are orchestrated by a hand-held controller, which can drive the sheath and scope together or independently. Electromagnetic navigation is incorporated into the system to provide intraoperative support using a CT scan obtained before the procedure.

In offering remote steering and scope configurations with additional structural support and increased articulation points, robotic-assisted bronchoscopy provides expanded articulation and reach in the pulmonary space and enhanced scope stability compared to standard flexible bronchoscopy.

Case study

Mrs. G, a 64-year-old woman with a history of smoking (1 pack/day 40 years) and renal cancer was referred to David DiBardino, MD, at Penn Interventional Pulmonology for evaluation of an abnormal chest CT scan.

Her renal cancer was resected without incident three years prior. However, a year before her kidney cancer diagnosis, a chest x-ray during an annual screening exam revealed a lung nodule that, despite an inconclusive CT transthoracic needle biopsy, was treated empirically with radiotherapy as presumed lung cancer.

At Penn, Mrs. G was alert and reported no recent pleuritic or exertional chest pain or cough productive of sputum, no respiratory distress and no recent fevers, chills, or night sweats. Her appetite was good. She had knee pain, for which she took NSAIDs and oral tramadol 50 mg, as needed. Her daily medications included prescriptions for the treatment of hypertension and hypercholesterolemia.

Reviewing Mrs. G’s chest CT, Dr. DiBardino noted an area of consolidation with scarring/calcification in the right lower lobe with associated calcified right hilar lymphadenopathy. Several small, well-circumscribed pulmonary nodules concerning for renal metastases were present in the right and left upper lobes, with no appreciable lymphadenopathy.

Of the lesions visible, only one, situated in the left upper lobe (LUL) at the confluence of the anterior and apicoposterior segment bifurcation, appeared to be accessible to bronchoscopy and biopsy.

Impression and plan

Dr. DiBardino discussed with Mrs. G a plan to perform a guided biopsy of the accessible nodule via robotic-assisted bronchoscopy, with the addition of cone-beam computed tomography (CBCT), and 3D/3D fusion with live augmented fluoroscopy, as needed.

After a discussion of the possible risks of anesthesia and other potential complications, Mrs. G agreed to the procedure.

Under general anesthesia, Mrs. G was intubated and her trachea and airway were examined using a therapeutic bronchoscope to exclude the presence of endobronchial disease.

Finding nothing remarkable, the bronchoscope was withdrawn and the Monarch© Robotic Bronchoscopy platform (Auris Health, Inc., Redwood City, CA) was inserted into the endotracheal tube.

At this point, electromagnetic navigation technology using the pre-procedure CT scan was used to register and position the bronchoscope. A pre-planned route designed via virtual bronchoscopy was then used with direct visualization and fluoroscopic guidance to advance the sheath and scope toward the targeted lesion in the LUL. A radial EBUS imaging probe was placed through the working channel to confirm the nodule location. This showed a highly eccentric view indicating the nodule was adjacent to the airway wall.

A cone beam CT was then performed at an inspiratory hold and the target lesion was identified in the LUL anterior segment. The lesion was highlighted using segmentation software and projected onto the live fluoroscopy image. A needle was then advanced into the lesion as directed by the live fluoroscopy overlay (Figure 1), and a second CBCT confirmed the needle within the nodule (Figure 2). Forceps were then placed through the needle hole to acquire 10 nodule biopsies.The robotic bronchoscope was then removed, and the procedure concluded.

Following a pathology report, Mrs. G was diagnosed with metastatic renal cell carcinoma. She is now considering immunotherapy with medical oncology.

Clinical trials in therapeutic robotic-assisted CBCT at Penn Medicine

The Penn Lung Center is currently participating in the POWER study (NCT05299606) a clinical trial of a microwave ablation system combined with robotic bronchoscopy with CBCT for the microwave ablation of oligometastatic tumors in the peripheral lung. This study is enrolling at the Penn Lung Center.

Participants and referring physicians are encouraged to contact Michelle Andronov (email Michelle.Andronov@pennmedicine.upenn.edu) for more information.

Locations

Harron Lung Center
Perelman Center for Advanced Medicine
3400 Civic Center Boulevard
West Pavilion, 1st Floor
Philadelphia, PA

Harron Lung Center University City
3737 Market Street, 10th Floor
Philadelphia, PA

About Penn Interventional Pulmonology at the Harron Lung Center

The Harron Lung Center is among the oldest and most advanced providers of interventional pulmonology in the nation.

An affiliate program, Penn Interventional Pulmonology, employs bronchoscopy and other minimally invasive techniques to diagnose and treat advanced lung conditions and works closely with the Pulmonary, Allergy, and Critical Care Division and thoracic surgery, medical and radiation oncology, otorhinolaryngology and transplant specialists to provide seamless care for advanced lung disease.

Referrals, consultations, scheduling

Please contact Gloria Foreman at 215-615-5864
or Gloria.Foreman@pennmedicine.upenn.edu.

Faculty Team

• David DiBardino, MD - Pulmonary Medicine
• Andrew R. Haas, MD, PhD - Pulmonary Medicine
• Christoph Hutchinson, MD - Pulmonary Medicine
• Anthony R. Lanfranco, MD - Pulmonary Medicine
• Kevin Ma, MD - Pulmonary Medicine