T4-non-small cell lung cancer invading the thoracic aorta: the role of the hybrid operating room

Introduction

The management of non-small cell lung cancer (NSCLC) has recently evolved and is highly dependent on its staging, molecular characteristics, and patient condition. The preoperative stage of NSCLC remains the primary factor in determining treatment and overall prognosis.

Thoracic surgery has made enormous progress in the last decade thanks to minimally invasive procedures, intra-operative imaging, artificial intelligence (AI), and technological evolution, moving towards precision surgery.

Systemic treatments such as immune checkpoint inhibitors (ICIs) and immunotherapy have also revolutionized the treatment of NSCLC (1-3), providing better outcomes in selected patients with locally advanced stages. Furthermore, in recent years, the panorama of indications for salvage or rescue surgery has expanded when systematic therapies are no longer effective (4-11).

In this new scenario, it is appropriate to evaluate the potential resectability of T4-NSCLC that invades the thoracic aorta (T4invAo) and reasonable to plan radical surgery in these patients.

Endovascular treatment is the gold standard for managing thoracic aortic pathology. This minimally invasive approach reduces perioperative morbidity and mortality rates compared to traditional open surgery. The hybrid operating room (HOR) plays a fundamental role in this context, allowing for the best technical strategy in a “one-stop” procedure. We present this article in accordance with the SUPER reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1724/rc).

Preoperative preparations and requirements

The study conformed to the provisions of the Declaration of Helsinki (as revised in 2013). Ethical approval was not requested because the surgical technique we proposed, which exploits an important technological evolution such as HOR, represents a well-known and widely adopted procedure in endovascular surgery. The participants gave informed consent before taking part in the study.

In patients with NSCLC, computed tomography (CT) angiography of the chest is commonly used to analyze the tumor and surrounding structures before surgery. In cases of suspected aortic invasion, characterized by an unclear border with the aortic wall unclear on CT, a three-dimensional (3D) reconstruction of the thoracic aorta is required to determine the precise size of the endoprosthesis that may be needed, its length, and its relationship to critical blood vessels. Today, the indication for surgery should be limited to cN0 (clinical Node) patients.

Additional abdominal computed tomographic angiography (CTA) is also required to study the access vessels.

Preoperative planning meticulously determines the proximal and distal landing zones for the endograft. This crucial step involves carefully considering two key factors:

• The estimated length of the aortic segment requiring surgical resection during the concomitant thoracic surgical procedure to achieve oncological radicality. This resection encompasses the tumor-infiltrated aortic segment and an additional 2 cm proximal and distal disease-free margin.
• The segment of the aorta to be covered by the endoprosthesis must include the resected portion and an additional 2–3 cm of the proximal and distal aorta. This extension is necessary to ensure proper apposition of the endograft to the aortic wall, thereby minimizing the risk of bleeding during or after the en-bloc resection (Figure 1).

Figure 1 Preoperative planning determines the endograft proximal and distal landing zones.

The appropriate endograft length can be selected after identifying the minimum aortic coverage area. The graft diameter is chosen to be a maximum of 10% larger than the native aorta diameter.

Our proposed approach requires access to an HOR equipped with a C-arm robotic system, an integrated operating table, and the collaboration of vascular surgeons.

Preoperatively, angio-CT images are uploaded to the HOR’s workstation, enabling a chest 3D reconstruction. The key landmarks [left subclavian artery (LSA) and celiac trunk] are manually marked to anticipate where the endovascular prosthesis should land. The tumor mass should be marked, enabling the surgeon to recognize the right landing zone intraoperatively and leave the correct disease-free proximal and distal margin to achieve oncological radicality (Video 1).

Step-by-step description

The first step involves a standard video-assisted thoracic surgery (VATS) diagnostic procedure at the HOR to confirm the preoperative suspicion of aortic wall invasion. According to our experience, the patient is positioned in the classic right lateral position under general anesthesia. However, we do not rule out the possibility of performing the procedure under local anesthesia.

If confirmed, the patient must be repositioned on the operating table in a supine position (second step). The third stage exploits the technology of HOR for the endovascular procedure. Maintaining both arms alongside the patient’s body allows the robotic C-arm to be maneuvered to the necessary angles (Video 2), ensuring adequate visualization of the relevant anatomical structures. Proper patient positioning facilitates optimal C-arm angulation throughout the thoracic endovascular aortic repair (TEVAR) procedure. After patient positioning, it is crucial to set up accurate image fusion for precise alignment and visualization of reference markers and anatomical structures visible on CT angiography but not on conventional angiography. To achieve this, two orthogonal fluoroscopic images are typically acquired with the patient positioned supine on the operating table. These images are usually obtained at 45° left anterior oblique and 45° right anterior oblique angles.

The preoperative CT reconstruction is manually matched to the two-dimensional (2D) fluoroscopic images using bony landmarks (spine/pelvic bones) for real-time 2D-3D fusion, which allows the visualization of the 3D reconstruction overlaid on live fluoroscopy. This procedure allows for a real-time localization of the neoplastic lesion relative to the thoracic aorta. The spine is usually more reliable than the pelvic bones to achieve an optimal overlap. The operator can further refine the overlay image manually if necessary.

Following image fusion, patients undergo standard pre-procedural preparation and draping. Ultrasound-guided percutaneous puncture of the bilateral common femoral arteries is performed. Anticoagulation is achieved with standard heparinization, with activated clotting time maintained above 200 seconds. On the side chosen for stent-graft deployment, either a single Prostar XL closure device (Abbott Vascular International, Diegem, Belgium) or two Perclose Prostyle devices (Abbott Vascular International) are deployed to achieve hemostasis at procedure conclusion. On the contralateral side, a 5 French introducer sheath is inserted, followed by the advancement of a Pigtail catheter into the thoracic aorta.

The C-arm should be oriented perpendicular to the plane of the aortic arch to maximize visualization and minimize geometric distortion, particularly of the proximal landing zone. This orientation prevents the superimposition of anatomical structures, which can introduce parallax errors and hinder accurate assessment of the target vessel.

Angiography is then performed to verify the accuracy of 2D-3D registration (focusing on the position of the LSA and the celiac trunk).

The stent graft is then inserted using standard techniques, with the assistance of the fusion image, to accurately identify the tumour and the planned deployment zone.

We aim to position the graft so that the neoplastic lesion resides within its mid-portion, thereby ensuring sufficient aortic coverage to guarantee the sealing capability of the endoprosthesis and achieving oncological radicality (Figure 1).

Following stent graft deployment, aortography confirms patency of the side vessels, particularly the left common carotid artery (LCCA) and/or the celiac trunk. Subsequently, the introducer sheaths are removed. Hemostasis on the contralateral side is achieved using either an Angioseal closure device (Terumo Europe, Leuven, Belgium) or a Mynx Control vascular closure device (Cordis Corporation, Miami Lakes, Florida, USA). After the closure of the small groin incision used for stent-graft deployment, thoracic surgical time starts. The endovascular procedure usually takes about 45 minutes and does not involve additional blood loss.

However, due to the frequent tumor location in the proximal segment of the descending aorta, it is often necessary to extend the stent-graft coverage proximally into Zone 2 of the aortic arch (12). It encompasses the portion of the aortic arch located between the LCCA and the LSA. This involves covering the origin of the LSA to achieve a secure proximal seal. Covering the origin of the LSA can lead to rare but severe complications, such as stroke in the posterior cerebrovascular territory. Additionally, it can increase the risk of spinal cord ischemia, particularly when the procedure involves covering multiple intercostal arteries. Current data and guidelines recommend preserving LSA flow whenever possible. Surgical revascularization options can be employed in these scenarios, such as an LCCA to LSA bypass or LSA transposition. Additionally, endovascular techniques offer alternative solutions for maintaining LSA perfusion during Zone 2 TEVAR. These techniques include branched TEVAR devices, in situ fenestration, and endovascular debranching with chimney/snorkel techniques.

In rare cases of more proximal aortic wall infiltration, the endoprosthesis may need to be positioned in Zone 1 or 0 of the aortic arch, which often necessitates the use of hybrid or fully endovascular revascularization techniques. Zone 0 is defined as the region between the distal coronary ostia and the brachiocephalic trunk and Zone 1 involves the aortic arch between the brachiocephalic trunk and the LCCA.

After completing the TEVAR, the patient must be returned to the right lateral position (fourth step). The fifth step concludes with en-bloc resection of the lung tumor and the involved aortic wall segment. Notably, this approach eliminates the need for traditional aortic clamping during the resection and requires only one anesthesia (Video 3). The morbidity and mortality rate according to our previous experience without using HOR is very low (6).

Postoperative considerations and tasks

Postoperatively, patients require antiplatelet therapy (acetylsalicylic acid 100 mg daily) and prophylactic low molecular weight heparin. Close monitoring of the neurological function of the legs is indicated to detect postoperative paraplegia due to spinal cord ischemia. In cases of paraplegia, cerebrospinal fluid drainage can improve spine perfusion through reduction of the cerebrospinal fluid pressure. However, the safety and effectiveness of this method are still debated (13).

Tips and pearls

• In cases of suspected aortic invasion, preoperative planning of a thoracic endoprosthesis in collaboration with vascular surgeons is recommended.
• During preoperative planning, consider:
  • The estimated length of the aortic segment requiring surgical resection during the concomitant thoracic surgical procedure to achieve oncological radicality. This resection encompasses the tumor-infiltrated aortic segment and an additional 2 cm proximal and distal disease-free margin.
  • Further proximal and distal 2–3 cm of aorta must be added to the planning to ensure adequate endograft apposition to the aortic wall, thus minimizing the risk of bleeding during or after en-bloc resection (Figure 1).
• For the endovascular procedure, keep both arms positioned along the patient’s body to allow the C-arm to be oriented perpendicular to the plane of the aortic arch.

Discussion

Surgical highlights

The two original highlights of our surgical proposal in NSCLC cases with suspected aortic invasion are as follows:

• Thoracic surgeons are encouraged to plan surgery in the HOR, if available, in close collaboration with vascular surgeons. Preoperative 3D reconstruction of the thoracic aorta is recommended to prepare the precise endoprosthesis that may be necessary.
• During preoperative planning, it is mandatory to combine endovascular and oncological concepts. This will determine the actual proximal and distal landing zones and identify the correct minimum aortic coverage area for the endoprosthesis (Figure 1).

Strengths and limitations

This is a real-world feasibility study.

The most important limitation of this study is that there is no evidence that our proposal improves outcomes. Further studies are needed.

Comparison with other surgical techniques and researches

Endovascular repair represents the predominant approach for treating descending thoracic aortic diseases (14-16). However, recent studies have shown that the traditional surgical approach, especially during pulmonary resections with thoracotomy, is still relevant (4,5). Notably, the endovascular approach eliminates the need for traditional aortic clamping during the resection and can reduce postoperative morbidity. Endovascular procedures are economically expensive compared to the traditional technique, but the reduction in morbidity certainly offsets the expense of endoprostheses.

Furthermore, our proposal of a unique procedure in HOR allows for a specific confirmation of aortic invasion while providing the best technological support.

Implications and actions recommended

Therefore, a suspected CT scan of aortic invasion does not require further diagnostic tests since diagnostic VATS represents the examination with greater sensitivity and specificity. Without aortic invasion, the procedure can be efficiently completed in the HOR. A multidisciplinary approach is recommended in T4invAo NSCLC.

Conclusions

In our experience, the use of the HOR should also be extended to selected cases of advanced NSCLC, such as T4invAo, that require surgery, allowing for more precise positioning of the thoracic endoprosthesis and the best technical strategy in a “one-stop” procedure.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1724/rc

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1724/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1724/coif). Siemens Healthcare invited F.Z. to speak at the ESTS Meeting 2024 without fees. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work and ensure that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study conformed to the provisions of the Declaration of Helsinki (as revised in 2013). Ethical approval was not requested because the surgical technique we proposed, which exploits an important technological evolution such as HOR, represents a well-known and widely adopted procedure in endovascular surgery. The participants gave informed consent before taking part in the study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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