Robotic bronchoscopy for pulmonary lesions: a review of existing technologies and clinical data

Bronchoscopic treatment of early-stage peripheral lung cancer

PURPOSE OF REVIEW

This review article focuses on bronchoscopic treatment of early-stage peripheral lung cancer.

RECENT FINDINGS

Bronchoscopic treatment modalities have garnered considerable attention for early-stage lung cancer. Studies using photodynamic therapy, thermal vapor ablation, laser ablation, cryoablation, and intra-tumoral injection have recently been published. However, the evidence supporting these approaches largely derives from single-arm studies with small sample sizes. Based on the IDEAL-D framework, no technology has progressed passed the idea phase (1). The main weakness of these technologies to date is lack of evidence suggesting they can achieve local control. Presently, no bronchoscopic intervention for lung cancer has sufficient data to warrant its use as part of the standard of care.

SUMMARY

Despite notable progress, current technologies remain suboptimal, and there is insufficient evidence to support their use outside of a research setting.

Added Value of a Robotic-assisted Bronchoscopy Platform in Cone Beam Computed Tomography-guided Bronchoscopy for the Diagnosis of Pulmonary Parenchymal Lesions

BACKGROUND

Cone beam computed tomography (CBCT)-guided bronchoscopic sampling of peripheral pulmonary lesions (PPLs) is associated with superior diagnostic outcomes. However, the added value of a robotic-assisted bronchoscopy platform in CBCT-guided diagnostic procedures is unknown.

METHODS

We performed a retrospective review of 100 consecutive PPLs sampled using conventional flexible bronchoscopy under CBCT guidance (FB-CBCT) and 100 consecutive PPLs sampled using an electromagnetic navigation-guided robotic-assisted bronchoscopy platform under CBCT guidance (RB-CBCT). Patient demographics, PPL features, procedural characteristics, and procedural outcomes were compared between the 2 cohorts.

RESULTS

Patient and PPL characteristics were similar between the FB-CBCT and RB-CBCT cohorts, and there were no significant differences in diagnostic yield (88% vs. 90% for RB-CBCT, P=0.822) or incidence of complications between the 2 groups. As compared with FB-CBCT cases, RB-CBCT cases were significantly shorter (median 58 min vs. 92 min, P<0.0001) and used significantly less diagnostic radiation (median dose area product 5114 µGy•m2 vs. 8755 µGy•m2, P<0.0001).

CONCLUSION

CBCT-guided bronchoscopy with or without a robotic-assisted bronchoscopy platform is a safe and effective method for sampling PPLs, although the integration of a robotic-assisted platform was associated with significantly shorter procedure times and significantly less radiation exposure.

[Clinical Application of Robotic Assisted Bronchoscopy in Peripheral Pulmonary Nodule Biopsy]

With the popularization of chest computed tomography (CT) lung cancer screening, the detection rate of peripheral pulmonary nodules is increasing day by day. Some patients could make clear diagnoses and receive early treatment by obtaining biopsy specimens. Transbronchial lung biopsy (TBLB) is one of the non-surgical biopsy methods for peripheral pulmonary nodules, which has less trauma and lower incidence of complications compared to percutaneous thoracic needle biopsy (PTNB). However, the diagnostic rate of TBLB is about 70%, which is still inferior to that of PTNB, which is about 90%. Since 2018, robot assisted bronchoscopy systems have been applied in clinical practice. This article reviews their application in further improving the diagnostic rate of peripheral pulmonary nodules by TBLB.
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Cone-beam CT-based Navigation With Augmented Fluoroscopy of the Airways for Image-guided Bronchoscopic Biopsy of Peripheral Pulmonary Nodules: A Prospective Clinical Study

BACKGROUND

Cone-beam computed tomography (CBCT) and augmented fluoroscopy (AF), in which intraprocedural CBCT data is fused with fluoroscopy, have been utilized as a novel image-guidance technique for biopsy of peripheral pulmonary lesions. The aim of this clinical study is to determine the safety and diagnostic performance of CBCT-guided bronchoscopy with advanced software tools for procedural planning and navigational guidance with AF of the airways for biopsy of peripheral pulmonary nodules.

METHODS

Fifty-two consecutive subjects were prospectively enrolled in the AIRWAZE study (December 2018 to October 2019). Image-guided bronchoscopic biopsy procedures were performed under general anesthesia with specific ventilation protocols in a hybrid operating room equipped with a ceiling-mounted C-arm system. Procedural planning and image-guided bronchoscopy with CBCT and AF were performed using the Airwaze investigational device.

RESULTS

A total of 58 pulmonary lesions with a median size of 19.0 mm (range 7 to 48 mm) were biopsied. The overall diagnostic yield at index procedure was 87.9% (95% CI: 77.1%-94.0%). No severe adverse events related to CBCT-guided bronchoscopy, such as pneumothorax, bleeding, or respiratory failure, were observed.

CONCLUSION

CBCT-guided bronchoscopic biopsy with augmented fluoroscopic views of the airways and target lesion for navigational guidance is technically feasible and safe. Three-dimensional image-guided navigation biopsy is associated with high navigational success and a high diagnostic yield for peripheral pulmonary nodules.

Robotic-assisted bronchoscopy for the diagnosis of peripheral pulmonary lesions: A systematic review and meta-analysis

Robotic-assisted bronchoscopy (RAB) is a newly developed bronchoscopic technique for the diagnosis of peripheral pulmonary lesions (PPLs). The objective of this meta-analysis was to analyze the diagnostic yield and safety of RAB in patients with PPLs. Five databases (PubMed, Embase, Web of Science, CENTRAL, and ClinicalTrials.gov) were searched from inception to April 2023. Two independent investigators screened retrieved articles, extracted data, and assessed the study quality. The pooled diagnostic yield and complication rate were estimated. Subgroup analysis was used to explore potential sources of heterogeneity. Publication bias was assessed using funnel plots and the Egger test. Sensitivity analysis was also conducted to assess the robustness of the synthesized results. A total of 725 lesions from 10 studies were included in this meta-analysis. No publication bias was found. Overall, RAB had a pooled diagnostic yield of 80.4% (95% CI: 75.7%-85.1%). Lesion size of >30 mm, presence of a bronchus sign, and a concentric radial endobronchial ultrasound view were associated with a statistically significantly higher diagnostic yield. Heterogeneity exploration showed that studies using cryoprobes reported better yields than those without cryoprobes (90.0%, 95% CI: 83.2%-94.7% vs. 79.0%, 95% CI: 75.8%-82.2%, p < 0.01). The pooled complication rate was 3.0% (95% CI: 1.6%-4.4%). In conclusion, RAB is an effective and safe technique for PPLs diagnosis. Further high-quality prospective studies still need to be conducted.

Interventional Pulmonology: Extending the Breadth of Thoracic Care

Interventional pulmonary medicine has developed as a subspecialty focused on the management of patients with complex thoracic disease. Leveraging minimally invasive techniques, interventional pulmonologists diagnose and treat pathologies that previously required more invasive options such as surgery. By mitigating procedural risk, interventional pulmonologists have extended the reach of care to a wider pool of vulnerable patients who require therapy. Endoscopic innovations, including endobronchial ultrasound and robotic and electromagnetic bronchoscopy, have enhanced the ability to perform diagnostic procedures on an ambulatory basis. Therapeutic procedures for patients with symptomatic airway disease, pleural disease, and severe emphysema have provided the ability to palliate symptoms. The combination of medical and procedural expertise has made interventional pulmonologists an integral part of comprehensive care teams for patients with oncologic, airway, and pleural needs. This review surveys key areas in which interventional pulmonologists have impacted the care of thoracic disease through bronchoscopic intervention.

"Tool-in-lesion" Accuracy of Galaxy System-A Robotic Electromagnetic Navigation BroncHoscopy With Integrated Tool-in-lesion-Tomosynthesis Technology: The MATCH Study

BACKGROUND

The Galaxy System (Noah Medical) is a novel robotic endoluminal platform using electromagnetic navigation combined with integrated tomosynthesis technology and augmented fluoroscopy. It provides intraprocedural imaging to correct computerized tomography (CT) to body divergence and novel confirmation of tool-in-lesion (TIL). The primary aim of this study was to assess the TIL accuracy of the robotic bronchoscope with integrated digital tomosynthesis and augmented fluoroscopy.

METHODS

Four operators conducted the experiment using 4 pigs. Each physician performed between 4 and 6 nodule biopsies for 20 simulated lung nodules with purple dye and a radio pacifier. Using Galaxy's "Tool-in-Lesion Tomography (TOMO+)" with augmented fluoroscopy, the physician navigated to the lung nodules, and a tool (needle) was placed into the lesion. TIL was defined by the needle in the lesion determined by cone-beam CT.

RESULTS

The lung nodule's average size was 16.3 ± 0.97 mm and was predominantly in the lower lobes (65%). All 4 operators successfully navigated to all (100%) of the lesions in an average of 3 minutes and 39 seconds. The median number of tomosynthesis sweeps was 3 and augmented fluoroscopy was utilized in most cases (17/20 or 85%). TIL after the final TOMO sweep was 95% (19/20) and tool-touch-lesion was 5% (1/20). Biopsy yielding purple pigmentation was also 100% (20/20).

CONCLUSION

The Galaxy System demonstrated successful digital TOMO confirmed TIL success in 95% (19/20) of lesions and tool-touch-lesion in 5% (1/20) as confirmed by cone-beam CT. Successful diagnostic yield was achieved in 100% (20/20) of lesions as confirmed by intralesional pigment acquisition.

Unlocking the potential of robotic-assisted bronchoscopy: overcoming challenging anatomy and locations

Robotic-assisted bronchoscopy (RAB) was recently added to the armamentarium of tools used in sampling peripheral lung nodules. Protocols and guidelines have since been published advocating use of large oral artificial airways, use of confirmatory technologies such as radial endobronchial ultrasound (R-EBUS), and preferably limiting sampling to pulmonary parenchymal lesions. We present three clinical cases where RAB was used unconventionally to sample pulmonary nodules in unusual locations and in patients with challenging airway anatomy. In case 1, we introduced the ion catheter through a nasal airway in a patient with trismus. In case 2, we established a diagnosis by sampling a station 5 lymph node, and in case 3, we sampled a lesion located behind an airway stump from previous thoracic surgery. All three patients would have presented significant challenges for alternative biopsy modalities such as CT-guided needle biopsy or video-assisted thoracic surgery.

Treatment strategies for malignant pulmonary nodule: beyond lobectomy. Point-counterpoint

PURPOSE OF REVIEW

Technological advancement in low-dose computed tomography resulted in an increased incidental discovery of early-stage lung cancer and multifocal ground glass opacity. The demand for parenchyma-preserving treatment strategies is greater now than ever. Pulmonary ablative therapy is a groundbreaking technique to offer local ablative treatment in a lung-sparing manner. It has become a promising technique in lung cancer management with its diverse applicability. In this article, we will review the current development of ablative therapy in lung and look into the future of this innovative technique.

RECENT FINDINGS

Current literature suggests that ablative therapy offers comparable local disease control to other local therapies and stereotactic body radiation therapy (SBRT), with a low risk of complications. In particular, bronchoscopic microwave ablation (BMWA) has considerably fewer pleural-based complications due to the avoidance of pleural puncture. BMWA can be considered in the multidisciplinary treatment pathway as it allows re-ablation and allows SBRT after BMWA.

SUMMARY

With the benefits which ablative therapy offers and its ability to incorporate into the multidisciplinary management pathway, we foresee ablative therapy, especially BMWA gaining significance in lung cancer treatment. Future directions on developing novel automated navigation platforms and the latest form of ablative energy would further enhance clinical outcomes for our patients.

Advances in navigating to the nodule and targeting

PURPOSE OF REVIEW

The multitude of available platforms and imaging modalities for navigational bronchoscopy, in combination with the various sampling tools that can be used intra-procedurally, is complex. This review seeks to describe the recent developments in peripheral bronchoscopy in regards to navigation, imaging, and sampling target lesions in the pulmonary parenchyma.

RECENT FINDINGS

Robotic assisted bronchoscopy has improved navigation to the peripheral airways for sampling of peripheral parenchymal lesions. These navigational platforms use innovative technology utilizing electromagnetic navigation and shape-sensing technology for guidance. The greatest improvement has been the stabilization of the robotic scope in the periphery to allow for accurate sampling. Despite improvements in these platforms, limitations of CT to body divergence continue to impact navigation to the lesion and therefore diagnostic yield of the procedure. Advanced intraprocedural imaging with cone beam CT or augmented fluoroscopy has been a recent focus to improve this area. Further, the adoption of newer sampling tools, such as cryobiopsy, offers the possibility of increased diagnostic yield.

SUMMARY

The developments in advanced bronchoscopy will impact the role of biopsy in the diagnosis of peripheral pulmonary parenchymal lesions.

Anesthetic considerations in interventional pulmonology

PURPOSE OF REVIEW

In this review, we highlight the important anesthetic consideration that relate to interventional bronchoscopic procedures for the management of central airway obstruction due to anterior mediastinal masses, endoluminal endobronchial obstruction, peripheral bronchoscopy for diagnosis and treatment of lung nodules, bronchoscopic lung volume reduction and medical pleuroscopy for diagnosis and management of pleural diseases.

RECENT FINDINGS

The advent of the field of Interventional Pulmonology has allowed for minimally invasive options for patients with a wide range of lung diseases which at times have replaced more invasive surgical procedures. Ongoing research has shed light on advancement in anesthetic techniques and management strategies that have increased the safety during peri-operative management during these complex procedures. Current evidence focusing on the anesthetic techniques is presented here.

SUMMARY

The field of Interventional Pulmonology requires a tailored anesthetic approach. Recent advancements and ongoing research have focused on expanding the partnership between the anesthesiologist and interventional pulmonologists which has led to improved outcomes for patients undergoing these procedures.

Separable Tendon-Driven Robotic Manipulator with a Long, Flexible, Passive Proximal Section

This work tackles practical issues which arise when using a tendon-driven robotic manipulator (TDRM) with a long, flexible, passive proximal section in medical applications. Tendon-driven devices are preferred in medicine for their improved outcomes via minimally invasive procedures, but TDRMs come with unique challenges such as sterilization and reuse, simultaneous control of tendons, hysteresis in the tendon-sheath mechanism, and unmodeled effects of the proximal section shape. A separable TDRM which overcomes difficulties in actuation and sterilization is introduced, in which the body containing the electronics is reusable and the remainder is disposable. An open-loop redundant controller which resolves the redundancy in the kinematics is developed. Simple linear hysteresis compensation and re-tension compensation based on the physical properties of the device are proposed. The controller and compensation methods are evaluated on a testbed for a straight proximal section, a curved proximal section at various static angles, and a proximal section which dynamically changes angles; and overall, distal tip error was reduced.

Soft tissue surgical robot for minimally invasive surgery: a review

Purpose

The current state of soft tissue surgery robots is surveyed, and the key technologies underlying their success are analyzed. State-of-the-art technologies are introduced, and future directions are discussed.

Methods

Relevant literature is explored, analyzed, and summarized.

Results

Soft tissue surgical robots had rapidly spread in the field of laparoscopic surgery based on the multi-degree-of-freedom movement of intra-abdominal surgical tools and stereoscopic imaging that are not possible in conventional surgery. The three key technologies that have made surgical robots successful are wire-driven mechanisms for multi-degree-of-freedom movement, master devices for intuitive remote control, and stereoscopic imaging technology. Recently, human-robot interaction technologies have been applied to develop user interfaces such as vision assistance and haptic feedback, and research on autonomous surgery has begun.

Conclusion

Robotic surgery not only replaces conventional laparoscopic surgery but also allows for complex surgeries that are not possible with laparoscopic surgery. On the other hand, it is also criticized for its high cost and lack of clinical superiority or patient benefit compared to conventional laparoscopic surgery. As various robots compete in the market, the cost of surgical robots is expected to decrease. Surgical robots are expected to continue to evolve in the future due to the need to reduce the workload of medical staff and improve the level of care demanded by patients.

Accuracy of Preliminary Pathology for Robotic Bronchoscopic Biopsy

BACKGROUND

Diagnosis and treatment of peripheral pulmonary lesions (PPLs) currently require at least 2 procedures. An all-in-1 approach would require diagnosing malignancy with preliminary cytology results. This study investigated the concordance between preliminary cytology and final pathology results in biopsies of PPLs obtained by shape-sensing robotic-assisted bronchoscopy (ssRAB).

METHODS

This study was a retrospective, consecutive, single-arm, single-center study of 110 ssRABs for PPLs. Concordance was defined as agreement between preliminary cytology and final pathology results. Accuracy, sensitivity, specificity, positive and negative predictive values, and safety outcomes were examined.

RESULTS

The concordance was 89% for needle biopsies, 85% for forceps biopsies, and 92% overall, with substantial agreement. There was no significant association of concordance with patients' demographics or lesion characteristics. Preliminary cytology resulted in a malignant diagnosis in 70%, a nonmalignant diagnosis in 4%, and a nondiagnostic result in 26%, with accuracy of 86% and sensitivity of 84%. The total complication rate was 3.6%, with a pneumothorax rate of 1.8%.

CONCLUSIONS

This study compared the concordance of preliminary pathology results with final pathology results for ssRAB biopsies in PPLs. The results showed that preliminary samples have a high concordance with final pathology results and may enable management of PPLs with a single anesthetic procedure including biopsy, staging, and treatment.

A Review of the Role of Robotics in Surgery: To DaVinci and Beyond!

Since its inception in 1985, robotic surgery has evolved into a mainstream surgical approach that has become virtually synonymous with minimally invasive surgery (MIS) and adopted across several specialties offering decreased patient morbidity and improved post-operative outcomes. This article discusses the current role of robotics in MIS and its varied applications, prevalence in the community and the future of the field.

Estimating follow-up CTs from geometric deformations of catheter implants in interstitial breast brachytherapy: A feasibility study using electromagnetic tracking

BACKGROUND

Electromagnetic tracking (EMT) systems have been shown to provide valuable information on the geometry of catheter implants in breast cancer patients undergoing interstitial brachytherapy (iBT). In the context of an extended patient-specific, pre-treatment verification, EMT can play a key role in determining the potential need and, if applicable, the appropriate time for treatment adaptation. To detect dosimetric shortcomings the relative position between catheters, and target volume and critical structures must be known. Since EMT cannot provide the anatomical context and standard imaging techniques such as cone-beam CT are not yet available in most brachytherapy suites, it is not possible to detect anatomic changes on a daily or fraction basis, so the need for adaptive planning cannot be identified.

PURPOSE

The aim of this feasibility study is to develop and evaluate a technique capable of estimating follow-up CTs at any time based on the initial treatment planning CT (PCT) and surrogate information about changes of the implant geometry from an EMT system.

METHODS

A deformation vector field is calculated from two different implant reconstructions acquired in treatment position through EMT, the first immediately after the PCT and the second at another time point during the course of treatment. The calculation is based on discrete displacement vectors of pairs of control and target points. These are extrapolated by means of different radial basis functions in order to cover the entire CT volume. The adequate parameters for the calculation of the deformation field were identified. By warping the PCT according to the deformation field, one obtains an estimated CT (ECT) that reflects the geometric changes. For the proof of concept, ECTs were computed for the time point of the clinical follow-up CT (FCT) that is embedded in the treatment workflow after the fourth fraction.

RESULTS

ECT and clinical FCTs of 20 patients were compared to each other quantitatively in terms of absolute Hounsfield unit differences in the planning target volume (PTV) and in a convex hull (CH) enclosing the catheters. The median differences were 31.2  and 29.5 HU for the CH and the PTV, respectively.

CONCLUSION

The proposed ECT approach was able to approximate the "anatomy of the day" and therefore, in principle, allows a dosimetric appraisal of the treatment plan quality before each fraction. In this way, it can contribute to a more detailed patient-specific quality assurance in iBT of the breast and help to identify the timing for a potential treatment adaptation.

Novel treatment of bronchopleural fistula in a lung transplant recipient with endobronchial sealant and endobronchial valve placement via robotic-assisted bronchoscopy

Bronchopleural fistulas (BPFs) are a dreaded complication following pulmonary surgery. Endobronchial valves (EVs), with endobronchial sealant (ES), instilled with robotic bronchoscopy (RB), allow occlusion of BPF, avoiding surgery. The patient was a 71-year-old woman with a history of chronic obstructive pulmonary disease and bronchiectasis who underwent bilateral lung transplantation and wedge resection of the right middle lobe and left lingula. A BPF was discovered on postoperative day (POD) 21. Conservative measures with chest tubes failed, and robotic-assisted bronchoscopy aided in reaching the bronchial segment and instilling ES, and EV was deployed with the conventional bronchoscope. The pneumothorax was cleared 12 days later, and on POD 56, she was discharged. The RB procedure was successful, with no pneumothorax or BPF symptoms after a median follow-up of POD 284. Robotic endobronchial closure of BPF with EV and ES is an effective treatment option avoiding invasive surgeries.

Innovative Invasive Loco-Regional Techniques for the Treatment of Lung Cancer

Surgical resection is still the standard treatment for early-stage lung cancer. A multimodal treatment consisting of chemotherapy, radiotherapy and/or immunotherapy is advised for more advanced disease stages (stages IIb, III and IV). The role of surgery in these stages is limited to very specific indications. Regional treatment techniques are being introduced at a high speed because of improved technology and their possible advantages over traditional surgery. This review includes an overview of established and promising innovative invasive loco-regional techniques stratified based on the route of administration, including endobronchial, endovascular and transthoracic routes, a discussion of the results for each method, and an overview of their implementation and effectiveness.

Learning Curve of Real-Time Imaging with C-Arm Based Tomography for Peripheral Lung Nodule Biopsy

The number of procedures required to attain proficiency with new bronchoscopic biopsy technologies for peripheral pulmonary lesions (PPLs) is uncertain. A prospective, single-center study evaluated learning curves of two operators performing PPL biopsies using a novel, real-time, intraoperative tomographic imaging system in consecutive procedures in adults with CT-detected PPLs. Operators were considered “proficient” when they asked three or fewer questions of the manufacturer’s clinical representative with no subsequent navigations in which they asked more than three questions. A total of 31 procedures were performed on 31 patients (Operator 1: 18, Operator 2: 13). Proficiency was achieved after an average of 10 procedures (Operator 1: 12, Operator 2: 8). From the learning curve to the post-learning curve period, the number of questions (median [IQR]: 23 [9.5–41.5] versus 0 [0–1], p < 0.001) and radiation dose (median [IQR]: 19.5 mGy/m2 [1.9–43.5] versus 1.5 mGy/m2 [0.7–3.3], p = 0.05) decreased significantly; procedure time decreased (median [IQR]: 12 min [7–20] versus 8 min [3–15], p = 0.29); and diagnostic yield increased significantly (13/20 cases [65%] to 11/11 cases [100%]), (p = 0.03). Based on this unique, clinically relevant method of assessing learning curve, proficiency with the Body Vision system was achieved at approximately the tenth procedure. These findings require validation in larger, diverse populations.

Modeling Tendon-actuated Concentric Tube Robots

Mechanics-based models have been developed to describe the shape of tendon-actuated continuum robots. Models have also been developed to describe the shape of concentric tube robots, i.e., nested combinations of precurved superelastic tubes. While an important class of continuum robots used in endoscopic and intracardiac medical applications combines these two designs, existing models do not cover this combination. Tendon-actuated models are limited to a single tube while concentric tube models do not include tendon-produced forces and moments. This paper derives a mechanics-based model for this hybrid design and assesses it using numerical and physical experiments involving a pair of tendon-actuated tubes. It is demonstrated that, similar to concentric tube robots, relative twisting between the tendon-actuated tubes is an important factor in determining overall robot shape.

Advanced Imaging for Robotic Bronchoscopy: A Review

Recent advances in navigational platforms have led bronchoscopists to make major strides in diagnostic interventions for pulmonary parenchymal lesions. Over the last decade, multiple platforms including electromagnetic navigation and robotic bronchoscopy have allowed bronchoscopists to safely navigate farther into the lung parenchyma with increased stability and accuracy. Limitations persist, even with these newer technologies, in achieving a similar or higher diagnostic yield when compared to the transthoracic computed tomography (CT) guided needle approach. One of the major limitations to this effect is due to CT-to-body divergence. Real-time feedback that better defines the tool-lesion relationship is vital and can be obtained with additional imaging using radial endobronchial ultrasound, C-arm based tomosynthesis, cone-beam CT (fixed or mobile), and O-arm CT. Herein, we describe the role of this adjunct imaging with robotic bronchoscopy for diagnostic purposes, describe potential strategies to counteract the CT-to-body divergence phenomenon, and address the potential role of advanced imaging for lung tumor ablation.

Transbronchial Techniques for Lung Cancer Treatment: Where Are We Now?

The demand for parenchyma-sparing local therapies for lung cancer is rising owing to an increasing incidence of multifocal lung cancers and patients who are unfit for surgery. With the latest evidence of the efficacy of lung cancer screening, more premalignant or early-stage lung cancers are being discovered and the paradigm has shifted from treatment to prevention. Transbronchial therapy is an important armamentarium in the local treatment of lung cancers, with microwave ablation being the most promising based on early to midterm results. Adjuncts to improve transbronchial ablation efficiency and accuracy include mobile C-arm platforms, software to correct for the CT-to-body divergence, metal-containing nanoparticles, and robotic bronchoscopy. Other forms of energy including steam vapor therapy and pulse electric field are under intensive investigation.

Solitary Lung Nodule: CT-Guided Transthoracic Biopsy vs Transbronchial Biopsy With Endobronchial Ultrasound and Flexible Bronchoscope, a Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Transbronchial lung biopsy with radial endobronchial ultrasound (rEBUS-TBB) and Computed tomography (CT) scan-guided transthoracic biopsy (CT-TTB) are commonly used to investigate peripheral lung nodules but high-quality data are still not clear about the diagnostic and safety profile comparison of these two modalities.

METHOD

We included all randomized controlled trials (RCT) comparing rEBUS-TBB with a flexible bronchoscope and CT-TTB for solitary lung nodules. Two reviewers extracted data independently on diagnostic performance and complication rates.

RESULTS

170 studies were screened, 4 RCT with a total of 325 patients were included. CT-TTB had a higher diagnostic yield than rEBUS-TBB (83.45% vs 68.82%, risk difference - 0.15, 95% CI, [- 0.24, - 0.05]), especially for lesion size 1-2 cm (83% vs 50%, risk difference - 0.33, 95% CI, [- 0.51, - 0.14]). For malignant diseases, rEBUS-TBB had a diagnostic yield of 75.75% vs 87.7% of CT-TTB. rEBUS-TBB had a significant better safety profile with lower risks of pneumothorax (2.87% vs 21.43%, OR = 0.12, 95% CI [0.05-0.32]) and combined outcomes of hospital admission, hemorrhage, and pneumothorax (8.62% vs 31.81%, OR 0.21, 95% CI, [0.11-0.40]). Factors increasing diagnostic yield of rEBUS were lesion size and localization of the probe but not the distance to the chest wall and hilum.

CONCLUSION

CT-TTB had a higher diagnostic yield than rEBUS-TBB in diagnosing peripheral lung nodules, particularly for lesions from 1 to 2 cm. However, rEBUS-TBB was significantly safer with five to eight times less risk of pneumothorax and composite complications of hospital admission, hemorrhage, and pneumothorax. The results of this study only apply to flexible bronchoscopy with radial ebus without navigational technologies. More data are needed for a comparison between CT-TTB with rEBUS-TBB combined with advanced navigational modalities.

Sublobar Resections

Sublobar resections are commonly performed operations that have seen an increase in applicability. The sublobar approach, comprising segmentectomy and wedge resections, can provide lung preservation and thus is better tolerated in select patients in comparison to lobectomy. These operations are offered for a variety of benign and malignant lesions. Understanding the indications and technical aspects of these approaches is paramount as improvements in lung cancer screening protocols and the imaging modalities has led to an increase in the detection of early-stage cancer. In this article, we discuss the anatomy, indications, technical approaches, and outcomes for sublobar resection.

Robotic Bronchoscopy: Review of Three Systems

Robotic bronchoscopy (RB) has been shown to improve access to smaller and more peripheral lung lesions, while simultaneously staging the mediastinum. Pre-clinical studies demonstrated extremely high diagnostic yields, but real-world RB yields have yet to fully matched up in prospective studies. Despite this, RB technology has rapidly evolved and has great potential for lung-cancer diagnosis and even treatment. In this article, we review the historical and present challenges with RB in order to compare three RB systems.

Follow-The-Leader Mechanisms in Medical Devices: A Review on Scientific and Patent Literature

Conventional medical instruments are not capable of passing through tortuous anatomy as required for natural orifice transluminal endoscopic surgery due to their rigid shaft designs. Nevertheless, developments in minimally invasive surgery are pushing medical devices to become more dexterous. Amongst devices with controllable flexibility, so-called Follow-The-Leader (FTL) devices possess motion capabilities to pass through confined spaces without interacting with anatomical structures. The goal of this literature study is to provide a comprehensive overview of medical devices with FTL motion. A scientific and patent literature search was performed in five databases (Scopus, PubMed, Web of Science, IEEExplore, Espacenet). Keywords were used to isolate FTL behavior in devices with medical applications. Ultimately, 35 unique devices were reviewed and categorized. Devices were allocated according to their design strategies to obtain the three fundamental sub-functions of FTL motion: steering, (controlling the leader/end-effector orientation), propagation, (advancing the device along a specific path), and conservation (memorizing the shape of the path taken by the device). A comparative analysis of the devices was carried out, showing the commonly used design choices for each sub-function and the different combinations. The advantages and disadvantages of the design aspects and an overview of their performance were provided. Devices that were initially assessed as ineligible were considered in a possible medical context or presented with FTL potential, broadening the classification. This review could aid in the development of a new generation of FTL devices by providing a comprehensive overview of the current solutions and stimulating the search for new ones.

Overview and update on molecular testing in non-small cell lung carcinoma utilizing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples

Lung carcinoma remains one of the most frequent and aggressive human neoplasms. Fortunately, in the last decades, the increasing knowledge of the molecular mechanisms leading to cancer development has allowed the use of targeted therapies with improvement of prognosis in many patients. Clinical management has also changed after the introduction of endobronchialultrasonographic bronchoscopy that allows a conservative staging of lung tumors, avoiding the need of mediastinoscopy for lymph node staging. Lung pathologists and cytopathologists are facing the challenge of giving the more comprehensive prognostic and predictive information with ever smaller tissue or cytological samples. The aim of this review is to summarize the molecular testing for non-small cell lung carcinoma and how pathologists can contribute to the patient's outcome with a conscious management of biological samples.

A Novel Robotic Bronchoscope System for Navigation and Biopsy of Pulmonary Lesions

Transbronchial biopsy sampling, as a minimally invasive method with relatively low risk, has been proved to be a promising treatment in the field of respiratory surgery. Although several robotic bronchoscopes have been developed, it remains a great challenge to balance size and flexibility, while integrating multisensors to realize navigation during complex airway networks. This paper proposes a novel robotic bronchoscope system composed by end effector with relatively small size, relevant actuation unit, and navigation system with path planning and surgical guidance capability. The main part of the end effector is machined by bidirectional groove on a nickel-titanium tube, which can realize bending, rotation, and translation 3 degrees of freedom. A prototype of the proposed robotic bronchoscope system is designed and fabricated, and its performance is tested through several experiments to verify the stiffness, flexibility, and navigation performance. The results show that the proposed system is with good environment adaptiveness, and it can become a promising biopsy method through natural cavity of the human body.

Robotic-assisted bronchoscopy versus CT-guided transthoracic biopsy for diagnosis of pulmonary nodules

BACKGROUND AND OBJECTIVE

Currently, computed tomography-guided transthoracic biopsy (CTTB) is the most accurate diagnostic approach for pulmonary nodules suspected of malignancy. Traditional bronchoscopy has shown suboptimal diagnostic sensitivity, but the emergence of robotic-assisted bronchoscopy (RAB) has the potential to improve diagnostic accuracy, maximize diagnostic yield and complete mediastinal and hilar staging in a single procedure. We aim to assess the efficacy and diagnostic performance of RAB compared to CTTB for diagnosing pulmonary nodules suspected of lung cancer.

METHODS

A multicenter retrospective review of consecutive patients who underwent RAB and CTTB for evaluating pulmonary nodules from January 2019 to March 2021 at Mayo Clinic Florida and Mayo Clinic Rochester, United States. Clinical and demographic information, nodule characteristics, outcomes and complications were compared between RAB and CTTB.

RESULTS

A total of 225 patients were included: 113 in the RAB group and 112 in the CTTB group. Overall diagnostic yield was 87.6% for RAB and 88.4% for CTTB. For malignant disease, RAB had a sensitivity of 82.1% and a specificity of 100%, CTTB had a sensitivity of 88.5% and a specificity of 100%. Complication rate was significantly higher for CTTB compared to RAB (17% vs. 4.4%; p = 0.002).

CONCLUSION

RAB, when available, can be as accurate as CTTB for sampling pulmonary nodules with similar or reduced complications and should be considered as a means for nodule biopsy, particularly when mediastinal staging is also clinically warranted.

Comparing modalities for risk assessment in patients with pulmonary lesions and nondiagnostic bronchoscopy for suspected lung cancer

BACKGROUND

Bronchoscopy is commonly utilized for non-surgical sampling of indeterminant pulmonary lesions, but nondiagnostic procedures are common. Accurate assessment of the risk of malignancy is essential for decision making in these patients, yet we lack tools that perform well across this heterogeneous group of patients. We sought to evaluate the accuracy of three previously validated risk models and physician-assessed risk (PAR) in patients with a newly identified lung lesion undergoing bronchoscopy for suspected lung cancer where the result is nondiagnostic.

METHODS

We performed an analysis of prospective data collected for the Percepta Bronchial Genomic Classifier Multicenter Registry. PAR and three previously validated risk models (Mayo Clinic, Veteran's Affairs, and Brock) were used to determine the probability of lung cancer (low, intermediate, or high) in 375 patients with pulmonary lesions who underwent bronchoscopy for possible lung cancer with nondiagnostic pathology. Results were compared to the actual adjudicated prevalence of malignancy in each pre-test risk group, determined with a minimum of 12 months follow up after bronchoscopy.

RESULTS

PAR and the risk models performed poorly overall in the assessment of risk in this patient population. PAR most closely matched the observed prevalence of malignancy in patients at 12 months after bronchoscopy, but all modalities had a low area under the curve, and in all clinical models more than half of all the lesions labeled as high risk were truly or likely benign. The studied risk model calculators overestimate the risk of malignancy compared to PAR, particularly in the subset in older patients, irregularly bordered nodules, and masses > 3 cm. Overall, the risk models perform only slightly better when confined to lung nodules < 3 cm in this population.

CONCLUSION

The currently available tools for the assessment of risk of malignancy perform suboptimally in patients with nondiagnostic findings following a bronchoscopic evaluation for lung cancer. More accurate and objective tools for risk assessment are needed.

TRIAL REGISTRATION

not applicable.

Cell-by-Cell: Unlocking Lung Cancer Pathogenesis

For lung cancers, cellular trajectories and fates are strongly pruned by cell intrinsic and extrinsic factors. Over the past couple of decades, the combination of comprehensive molecular and genomic approaches, as well as the use of relevant pre-clinical models, enhanced micro-dissection techniques, profiling of rare preneoplastic lesions and surrounding tissues, as well as multi-region tumor sequencing, have all provided in-depth insights into the early biology and evolution of lung cancers. The advent of single-cell sequencing technologies has revolutionized our ability to interrogate these same models, tissues, and cohorts at an unprecedented resolution. Single-cell tracking of lung cancer pathogenesis is now transforming our understanding of the roles and consequences of epithelial-microenvironmental cues and crosstalk during disease evolution. By focusing on non-small lung cancers, specifically lung adenocarcinoma subtype, this review aims to summarize our knowledge base of tumor cells-of-origin and tumor-immune dynamics that have been primarily fueled by single-cell analysis of lung adenocarcinoma specimens at various stages of disease pathogenesis and of relevant animal models. The review will provide an overview of how recent reports are rewriting the mechanistic details of lineage plasticity and intra-tumor heterogeneity at a magnified scale thanks to single-cell studies of early- to late-stage lung adenocarcinomas. Future advances in single-cell technologies, coupled with analysis of minute amounts of rare clinical tissues and novel animal models, are anticipated to help transform our understanding of how diverse micro-events elicit macro-scale consequences, and thus to significantly advance how basic genomic and molecular knowledge of lung cancer evolution can be translated into successful targets for early detection and prevention of this lethal disease.

Continuum Robots for Medical Interventions

Continuum robots are not constructed with discrete joints but, instead, change shape and position their tip by flexing along their entire length. Their narrow curvilinear shape makes them well suited to passing through body lumens, natural orifices, or small surgical incisions to perform minimally invasive procedures. Modeling and controlling these robots are, however, substantially more complex than traditional robots comprised of rigid links connected by discrete joints. Furthermore, there are many approaches to achieving robot flexure. Each presents its own design and modeling challenges, and to date, each has been pursued largely independently of the others. This article attempts to provide a unified summary of the state of the art of continuum robot architectures with respect to design for specific clinical applications. It also describes a unifying framework for modeling and controlling these systems while additionally explaining the elements unique to each architecture. The major research accomplishments are described for each topic and directions for the future progress needed to achieve widespread clinical use are identified.

Robotic Assisted-Bronchoscopy With Cone-Beam CT ICG Dye Marking for Lung Nodule Localization: Experience Beyond USA

Electromagnetic navigation bronchoscopy (ENB)-guided indocyanine green (ICG) fluorescence dye marking of subsolid, small and deep lung lesions facilitates subsequent minimally invasive lung resection surgeries. The novel robotic-assisted bronchoscopy (RAB) platform can improve the accuracy and yield of ENB biopsy, and the use of RAB has been extended to ICG dye marking. However, performing this procedure in the hybrid operating room guided by cone-beam CT (CBCT) with immediate proceed to lung surgery has not been well reported. We studied the safety, feasibility and clinical outcomes of 5 consecutive cases performed between December 2021 and March 2022. Navigation success was 100% while localization success using ICG was 80%. The benefits and pitfalls of robotic bronchoscopy procedures, and challenges of combining with hybrid operating room CBCT were discussed in detail. In conclusion, robotic-assisted bronchoscopy is a promising and useful tool for ICG fluorescence dye-marking, providing accurate navigation, superior maneuverability and improved ergonomics compared to conventional bronchoscopy-guided ENB procedures. Learning curve is reasonable, but meticulous system set up to incorporate the robotic system into existing CBCT platform may be required to ensure a smooth procedure.

Shape-Sensing Robotic-Assisted Bronchoscopy in the Diagnosis of Pulmonary Parenchymal Lesions

BACKGROUND

The landscape of guided bronchoscopy for the sampling of pulmonary parenchymal lesions is evolving rapidly. Shape-sensing robotic-assisted bronchoscopy (ssRAB) recently was introduced as means to allow successful sampling of traditionally challenging lesions.

RESEARCH QUESTION

What are the feasibility, diagnostic yield, determinants of diagnostic sampling, and safety of ssRAB in patients with pulmonary lesions?

STUDY DESIGN AND METHODS

Data from 131 consecutive ssRAB procedures performed at a US-based cancer center between October 2019 and July 2020 were captured prospectively and analyzed retrospectively. Definitions of diagnostic procedures were based on prior standards. Associations of procedure- and lesion-related factors with diagnostic yield were examined by univariate and multivariate generalized linear mixed models.

RESULTS

A total of 159 pulmonary lesions were targeted during 131 ssRAB procedures. The median lesion size was 1.8 cm, 59.1% of lesions were in the upper lobe, and 66.7% of lesions were beyond a sixth-generation airway. The navigational success rate was 98.7%. The overall diagnostic yield was 81.7%. Lesion size of ≥ 1.8 cm and central location were associated significantly with a diagnostic procedure in the univariate analysis. In the multivariate model, lesions of ≥ 1.8 cm were more likely to be diagnostic compared with lesions < 1.8 cm, after adjusting for lung centrality (OR, 12.22; 95% CI, 1.66-90.10). The sensitivity and negative predictive value of ssRAB for primary thoracic malignancies were 79.8% and 72.4%, respectively. The overall complication rate was 3.0%, and the pneumothorax rate was 1.5%.

INTERPRETATION

This study was the first to provide comprehensive evidence regarding the usefulness and diagnostic yield of ssRAB in the sampling of pulmonary parenchymal lesions. ssRAB may represent a significant advancement in the ability to access and sample successfully traditionally challenging pulmonary lesions via the bronchoscopic approach, while maintaining a superb safety profile. Lesion size seems to remain the major predictor of a diagnostic procedure.

Factors Associated with Diagnostic Accuracy of Robotic Bronchoscopy with 12-month Follow-up

BACKGROUND

Robotic Bronchoscopy (RB) aims to increase the diagnostic yield of guided bronchoscopy by providing improved navigation, farther reach, and stability during lesion sampling.

METHODS

We reviewed data on consecutive cases in which robotic bronchoscopy was used to diagnose lung lesions from June 15^th, 2018 to December 15^th, 2019 at the University of Chicago Medical Center.

RESULTS

The median lesion size was 20.5 mm. All patients had at least 12 months of follow-up. The overall diagnostic accuracy was 77% (95/124). The diagnostic accuracy was 85%, 84% and 38% for concentric, eccentric and absent r-EBUS views, respectively (p < 0.001). A positive r-EBUS view and lesions size of 20-30 mm had higher odds of achieving a diagnosis on multivariate analysis. The 12-month diagnostic accuracy, sensitivity, specificity, positive and negative predictive value for malignancy was 77%, 69%, 100%, 100% and 58%, respectively. Pneumothorax was noted in 1.6% (2) cases with bleeding reported in 3.2% (4) cases. No post-procedure respiratory failure was noted.

CONCLUSIONS

The overall diagnostic accuracy using RB for pulmonary lesion sampling in our cohort with 12-month follow-up compared favorably to established guided bronchoscopy technologies. Lesion size ≥20 mm and confirmation by r-EBUS predicted higher accuracy independent of concentric or eccentric r-EBUS patterns.

Retrospective Review of Flexible Bronchoscopy in Pediatric Cancer Patients

The use of flexible bronchoscopy (FB) with bronchoalveolar lavage (BAL) to diagnose and manage pulmonary complications has been shown to be safe in adult cancer patients, but whether its use is safe in pediatric cancer patients remains unclear. Thus, to describe the landscape of FB outcomes in pediatric cancer patients and to help define the populations most likely to benefit from the procedure, we undertook a retrospective review of FBs performed in patients younger than 21 years treated at our institution from 2002 to 2017. We found that a greater volume of total fluid instilled during BAL was significantly associated with increased probabilities of positive BAL culture (p=0.042), positive bacterial BAL culture (p=0.037), and positive viral BAL culture (p=0.0496). In more than half of the FB cases, findings resulted in alterations in antimicrobial treatment. Our study suggests that for pediatric cancer patients, FB is safe, likely provides diagnostic and/or therapeutic benefits, and has implications for treatment decisions.

Joining Forces: How to Coordinate Large, Multicenter Randomized Trials

This article details the pros, cons, challenges/pitfalls, and elements required for the successful conduct of multicenter randomized trials, with specific focus on trials related to pleural diseases. Several networks dedicated to the multicenter study of important pleural conditions have developed, yielding practice-changing studies in pleural disease. This review describes the importance of multicenter trials, major elements required for the conduct of such trials, and lessons learned from the ongoing development of the Interventional Pulmonary Outcomes Group, a consortium of interventional pulmonologists dedicated to advancing diagnostic and management strategies in pleural, pulmonary parenchymal, and airway disease by generating high-quality multicenter evidence.

The PEARL Approach for CT-guided Lung Biopsy: Assessment of Complication Rate

Background Percutaneous CT-guided biopsy of lung nodules is an established method with high diagnostic accuracy but a high rate of pneumothorax and chest tube insertion compared with endobronchial methods. Purpose To investigate the effect of a protocol combining patient positioning biopsy-side down, needle removal during expiration, autologous blood patch sealing, rapid rollover, and pleural patching (PEARL) on complication rate after percutaneous CT-guided lung biopsy, especially chest tube insertion. Materials and Methods In a secondary analysis of both prospectively and retrospectively acquired data from December 2019 to November 2020, consecutive participants underwent biopsy with use of the PEARL protocol (prospective data) and were compared with patients who underwent biopsy at the same tertiary cancer center according to the standard method without any additional techniques (controls, retrospective data). Patient demographics, lesion characteristics, intraprocedural data, complications, and histologic results were recorded and compared. Results One hundred patients in the control group (mean age ± standard deviation, 63 years ± 12; 61 men) and 100 participants in the PEARL group (mean age, 64 years ± 12; 48 men) were evaluated. No differences were found in patient and lesion characteristics. The emphysema rate was 47 of 100 patients (47%) in both groups. The rate of pneumothorax was 37 of 100 patients (37%) in the control group versus 16 of 100 (16%) in the PEARL group (P = .001). Of the pneumothoraxes that occurred, fewer were during the intervention in the PEARL group, with 21 of 37 onsets (57%) in the control group versus three of 16 onsets (19%) in the PEARL group (P < .001). A chest tube was inserted in 13 of 100 patients (13%) in the control group and only in one of 100 (1%) in the PEARL group (P = .002). Histologic findings were diagnostic in 94 of 100 patients (94%) in the control group and 95 of 100 (95%) in the PEARL group (P > .99). Conclusion During CT-guided percutaneous lung biopsy, a protocol of positioning biopsy-side down, needle removal during expiration, autologous blood patch sealing, rapid rollover, and pleural patching, or PEARL, reduced rates of pneumothorax and chest tube insertion. © RSNA, 2021.

Advances in Diagnostic Bronchoscopy

The increase in incidental discovery of pulmonary nodules has led to more urgent requirement of tissue diagnosis. The peripheral pulmonary nodules are especially challenging for clinicians. There are various modalities for diagnosis and tissue sampling of pulmonary lesions, but most of these modalities have their own limitations. This has led to the development of many advanced technical modalities, which have empowered pulmonologists to reach the periphery of the lung safely and effectively. These techniques include thin/ultrathin bronchoscopes, radial probe endobronchial ultrasound (RP-EBUS), and navigation bronchoscopy—including virtual navigation bronchoscopy (VNB) and electromagnetic navigation bronchoscopy (ENB). Recently, newer technologies—including robotic-assisted bronchoscopy (RAB), cone-beam CT (CBCT), and augmented fluoroscopy (AF)—have been introduced to aid in the navigation to peripheral pulmonary nodules. Technological advances will also enable more precise tissue sampling of smaller peripheral lung nodules for local ablative and other therapies of peripheral lung cancers in the future. However, we still need to overcome the CT-to-body divergence, among other limitations. In this review, our aim is to summarize the recent advances in diagnostic bronchoscopy technology.

Sight Unseen: Diagnostic Yield and Safety Outcomes of a Novel Multimodality Navigation Bronchoscopy Platform with Real-Time Target Acquisition

BACKGROUND

Several advanced bronchoscopy platforms are currently available, but the clinical data supporting their use vary. Electromagnetic navigation bronchoscopy (ENB) remains the dominant technology; it is limited by its reliance on preoperative computed tomography, which only approximates patient anatomy during the procedure. Recently, ENB was enhanced with the (1) addition of digital tomosynthesis-based navigation correction, (2) improvements in planning algorithms, and (3) continuous real-time guidance (Illumisite™; Medtronic, Minneapolis, MN, USA). There are currently no clinical data on the diagnostic yield and safety profile of this system.

OBJECTIVES

The primary objective of this study is to describe the diagnostic yield of the first 100 pulmonary parenchymal lesions sampled using the multimodality navigation bronchoscopy (MNB) platform. The secondary objective is to describe safety.

METHODS

In this single-center prospective observational study, a database was maintained to track patient, procedural, and outcome data for the first 100 consecutive lesions sampled using the MNB platform at an academic quaternary referral center. Descriptive statistics and univariate and multivariate analyses are reported.

RESULTS

The overall diagnostic yield of samples acquired was 79% (79/100). In the cohort where digital tomosynthesis was used, the diagnostic yield was 83% (69/83). Sensitivity for malignancy was 71% (52/73). Overall complication rates were low: pneumothorax (n = 3, 3%) and bleeding requiring intervention (n = 2, 2%). There were no procedural-related hospital admissions.

CONCLUSIONS

The MNB system performed favorably. Platform superiority cannot be established without future prospective and comparative studies.

Lung Nodule Evaluation Using Robotic-Assisted Bronchoscopy at a Veteran's Affairs Hospital

The incidence of lung nodules has increased with improved diagnostic imaging and screening protocols. Despite improvements for diagnosing pulmonary nodules with technologies such as electromagnetic navigational bronchoscopy (ENB), several limitations still exist including adequate visualization, localization, and diagnostic yield. Robotic-assisted bronchoscopy with ENB has been introduced as a method to overcome these shortcomings. We describe our initial experience in evaluating lung nodules with robotic assisted bronchoscopy. We retrospectively reviewed data on the first 25 patients that underwent robotic-assisted bronchoscopy and biopsy. We analyzed success with localization, diagnostic yield, and post procedural morbidity. Diagnostic yield was 96% (24/25) with no periprocedural morbidity. The majority of nodules were malignant or atypical (76%) and were located in the right upper lobe. Diameter ranged between 0.8–6.9 cm (median size 1–2 cm). Seventy-five percent of patients underwent subsequent treatment for cancer based on these results, with 25% having continued surveillance. Robotic assisted bronchoscopy is safe and accurate. Studies with larger numbers will allow better understanding of the diagnostic yield and clinical utility of this approach in comparison to other diagnostic tools for lung nodules.

Alternative methods for local ablation-interventional pulmonology: a narrative review

OBJECTIVE

To discuss and summarise the background and recent advances in the approach to bronchoscopic ablative therapies for lung cancer, focusing on focal parenchymal lesions.

BACKGROUND

This series focusses on the challenges highlighted by increasing recognition of the prognostically more favourable oligometastatic disease rather than the more frequent, but prognostically poor, high tumour burden metastatic disease. While surgery, stereotactic body radiation therapy (SBRT), and trans-thoracic percutaneous ablative techniques such as microwave (MWA) and radiofrequency ablation (RFA) are well recognised options for selected cases of pulmonary oligometastasis, bronchoscopic approaches to pulmonary tumour ablation are becoming realistic alternatives. An underlying tenet driving research and implementation in this domain is that percutaneous ablative techniques are obliged to traverse the pleura leading to a high rate of pneumothorax, and risks also goes up for peri-vascular lesions. Historically low yield bronchoscopic targeting of isolated peripheral tumors have significantly improved by incorporating multi-modality high resolution imaging and processing, including navigation planning and real-time image guidances (ultrasound, electromagnetic navigation, cone-beam CT). Combining advanced image guidance with ablative technology adaptations for bronchoscopic delivery opens up the options for high dose local ablative therapies that may reduce transthoracic complications and provide palliative to curative options for limited stage primary and oligometastatic diseases.

METHODS

We conduct a narrative review of the literature summarizing the history of bronchoscopic tumor ablation approaches, technical details including biologic rational for their uses, and current evidence for each modality, as well as investigations into future applications. Because of the relative paucity of prospective studies, we have been very inclusive in our inclusion of experiences from the published clinical databases.

CONCLUSIONS

Whilst surgical resection and SBRT remain the current mainstay of curative therapies for peripheral cancers, in the foreseeable future, developments and further research will see bronchoscopic ablative therapies become viable lung sparing alternatives in those deemed suitable. The future is bright.

Robotic bronchoscopy for peripheral pulmonary lesions: a convergence of technologies

PURPOSE OF REVIEW

Robotic bronchoscopy is the newest advanced diagnostic bronchoscopy technology for biopsying peripheral pulmonary lesions; sensitivity for malignancy is currently suboptimal using modalities, such as radial endobronchial ultrasound or electromagnetic navigational bronchoscopy. We review the pitfalls of prior methods and the technological advancements with robotic bronchoscopy.

RECENT FINDINGS

The contributors to reduced diagnostic sensitivity with current approaches include limitations in: navigation to the target, confirmation once the target is reached, and tissue acquisition. CT to body divergence with virtual reality methods, such as with electromagnetic navigation, potential false-positive confirmation with radial endobronchial ultrasound because of intraprocedural induced atelectasis, and lack of bronchoscopic and instrument maneuverability are all limitations to improving sensitivity. Robotic bronchoscopy enhances navigation through target pathway selection, allows for further reach in the distal airways, and improves tissue acquisition with more flexible and maneuverable biopsy instruments but lacks a high-fidelity target confirmation system.

SUMMARY

Robotic bronchoscopy shows promise in biopsying peripheral lesions. Current published studies focus on diagnostic yield with robotic bronchoscopy. Future studies with long-term follow-up will be needed to assess diagnostic sensitivity for lung cancer and if robotic bronchoscopy is superior to other advanced diagnostic bronchoscopic techniques for peripheral pulmonary lesions.

Planar Body-Mounted Sensors for Electromagnetic Tracking

Electromagnetic tracking is a safe, reliable, and cost-effective method to track medical instruments in image-guided surgical navigation. However, patient motion and magnetic field distortions heavily impact the accuracy of tracked position and orientation. The use of redundant magnetic sensors can help to map and mitigate for patient movements and magnetic field distortions within the tracking region. We propose a planar inductive sensor design, printed on PCB and embedded into medical patches. The main advantage is the high repeatability and the cost benefit of using mass PCB manufacturing processes. The article presents new operative formulas for electromagnetic tracking of planar coils on the centimetre scale. The full magnetic analytical model is based on the mutual inductance between coils which can be approximated as being composed by straight conductive filaments. The full model is used to perform accurate system simulations and to assess the accuracy of faster simplified magnetic models, which are necessary to achieve real-time tracking in medical applications.