Robotic Segmentectomy for Anatomically Complex Tumors: Technical Principles, Evidence, and Clinical Applications

Abstract

Robotic segmentectomy has emerged as an important anatomic lung-sparing strategy for selected patients with early-stage non-small cell lung cancer and other localized pulmonary tumors. Its role becomes particularly relevant when lesions are situated near segmental bronchi, pulmonary arteries, intersegmental planes, or anatomically variant vascular structures. Conventional thoracoscopic segmentectomy can be technically demanding in these circumstances because of restricted instrument articulation, limited visualization of deep hilar structures, and difficulty achieving an adequate parenchymal margin. Robotic platforms may address several of these limitations through three-dimensional magnified imaging, wristed instruments, tremor filtration, and improved control of hilar dissection. Nevertheless, robotic surgery does not eliminate the risks of bleeding, inadequate margins, prolonged operative time, or conversion to lobectomy. Careful patient selection, high-quality imaging, three-dimensional anatomical planning, intraoperative localization, and surgeon experience are essential. Current evidence supports anatomic segmentectomy for selected peripheral small tumors, particularly when oncologic margins and systematic nodal evaluation can be achieved. For anatomically complex tumors, the evidence base remains predominantly observational, although contemporary series suggest favorable perioperative outcomes and increasing feasibility. This review examines the clinical rationale, technical considerations, risks, guideline context, and future development of robotic segmentectomy in complex pulmonary anatomy.

Introduction

Anatomic segmentectomy involves removal of a defined bronchopulmonary segment together with its corresponding segmental artery, vein, and bronchus. Unlike wedge resection, it follows the anatomical organization of the lung and can provide a more reliable oncologic margin while preserving functional parenchyma compared with lobectomy. The procedure is increasingly used for carefully selected patients with small, peripheral, node-negative lung cancers, patients with limited pulmonary reserve, and individuals who may develop metachronous primary tumors. Its application to anatomically complex tumors is more challenging because the lesion may be central within a segment, close to the intersegmental boundary, adjacent to major hilar structures, or associated with unusual branching patterns.

Robotic-assisted surgery has expanded the technical options for these cases. The surgeon operates from a stable, magnified, three-dimensional view and can use articulating instruments to dissect around vessels and bronchi with greater dexterity than is generally available with conventional straight thoracoscopic instruments. However, technological capability must not be confused with oncologic appropriateness. The central objectives remain complete tumor removal, an adequate parenchymal margin, appropriate lymph-node assessment, avoidance of tumor rupture, and preservation of functional lung tissue. A multidisciplinary evaluation is therefore necessary before recommending a complex robotic segmentectomy.

Epidemiology / Disease Burden

Lung cancer remains one of the leading causes of cancer-related mortality worldwide. The increasing use of low-dose computed tomography has resulted in detection of smaller, earlier-stage pulmonary nodules, including lesions that may be suitable for sublobar resection. At the same time, many patients undergoing evaluation are older adults with chronic obstructive pulmonary disease, cardiovascular disease, impaired diffusion capacity, or previous lung resections. For these patients, preservation of functional lung parenchyma may reduce postoperative respiratory disability and maintain eligibility for future treatment.

The burden of disease is not limited to primary lung cancer. Pulmonary metastases, multifocal adenocarcinoma-spectrum lesions, carcinoid tumors, and selected benign or low-grade neoplasms may also require anatomic resection. Complex segmental anatomy is encountered particularly in tumors located in the superior segments of the lower lobes, the apical or posterior segments of the upper lobes, the lingula, the right middle lobe, and basal segments with multiple arterial or venous branches. Anatomic variation is common, and unrecognized variants can increase the likelihood of vascular injury or an incomplete resection.

Pathophysiology

The oncologic rationale for segmentectomy is based on the biological behavior and anatomical spread of localized tumors. Early-stage non-small cell lung cancers may remain confined to a small region of lung before lymphatic or distant dissemination occurs. Removing the involved segment with its draining lymphovascular structures can achieve local control while preserving more parenchyma than lobectomy. The adequacy of this approach depends on tumor size, invasive characteristics, consolidation-to-tumor ratio, spread through air spaces, lymphovascular invasion, and the relationship between the lesion and the planned resection margin.

Complex tumors may involve or abut intersegmental planes, segmental vessels, or bronchi. Tumor proximity to these structures can require tailored division of the parenchymal plane, bronchial reconstruction, vascular control, or removal of an adjacent subsegment. The surgeon must account for both the three-dimensional location of the tumor and the direction of potential microscopic extension. A margin that appears adequate on axial imaging may be insufficient after the true segmental anatomy is reconstructed intraoperatively. Mechanically, robotic articulation facilitates precise hilar dissection, but oncologic safety still depends on anatomical judgment and pathological confirmation.

Risk Factors

Risk factors for tumors considered for complex segmentectomy are broadly similar to those for lung malignancy and include tobacco exposure, occupational carcinogens, radon, air pollution, familial susceptibility, and pre-existing pulmonary fibrosis. Older age and chronic cardiopulmonary disease influence the choice of a parenchyma-sparing procedure but also increase perioperative risk. Reduced forced expiratory volume, diminished diffusing capacity, pulmonary hypertension, frailty, and poor exercise tolerance may make lobectomy less desirable, although they can also increase the risk of prolonged air leak, pneumonia, atrial arrhythmia, and conversion.

Procedure-specific risk is higher when the lesion is deep, central, close to a major vessel, associated with variant anatomy, or difficult to localize by palpation. Previous ipsilateral surgery, pleural adhesions, neoadjuvant treatment, and inflammatory changes can further complicate dissection. A history of anticoagulant use or bleeding disorders requires individualized perioperative planning because robotic access does not remove the consequences of uncontrolled hilar hemorrhage.

Clinical Features

Most small peripheral tumors are asymptomatic and are discovered incidentally or through screening. Symptomatic patients may report cough, hemoptysis, chest discomfort, dyspnea, recurrent localized infection, or unexplained weight loss, although these findings are nonspecific. Carcinoid tumors may present with recurrent pneumonia or airway obstruction, while metastatic lesions are often identified during surveillance for an extrapulmonary primary cancer.

Clinical assessment should include functional status, cardiopulmonary comorbidity, prior malignancy, smoking history, nutritional condition, and the possibility of multifocal disease. The intended resection should be considered within the patient’s long-term treatment trajectory. Preserving parenchyma may be especially valuable in individuals at risk for a second primary lung cancer, but a limited operation should not be selected if it compromises local control or nodal staging.

Diagnosis

Thin-section contrast-enhanced computed tomography is the foundation of anatomical planning. The report should describe tumor size, density, solid and ground-glass components, distance from the pleura, proximity to segmental bronchi and vessels, and evidence of nodal or distant disease. Three-dimensional reconstruction can display the spatial relationship between the tumor and the segmental bronchovascular tree and may identify anomalous arteries, early venous drainage, or fused intersegmental veins.

Positron emission tomography combined with computed tomography is useful for staging selected patients, although small or indolent tumors may show low metabolic activity. Brain imaging and additional staging investigations should be performed according to tumor stage and clinical indication. Tissue diagnosis is desirable when it will alter management, but it is not always mandatory before resection of a highly suspicious, technically resectable nodule. Pulmonary function testing, diffusion capacity, cardiopulmonary exercise assessment, and formal risk estimation help determine whether segmentectomy offers a meaningful functional advantage.

Intraoperative localization may be necessary for small, deep, or nonpalpable lesions. Bronchoscopic dye marking, microcoil placement, radiotracer guidance, and hybrid operating room techniques can assist localization, although each method has logistical and procedural risks. Frozen-section assessment of the margin and selected lymph nodes may support intraoperative decision-making, particularly when unexpected invasive disease or an inadequate margin is identified.

Treatment & Management

Patient selection should integrate tumor biology, anatomical feasibility, pulmonary reserve, and institutional expertise. The preferred candidate generally has a small peripheral lesion, clinically negative mediastinal nodes, a favorable tumor-to-margin relationship, and an anatomic plan that permits complete removal of the involved segment. In complex cases, preoperative simulation should define the target segment, arterial branches, venous drainage, bronchial anatomy, intersegmental planes, and possible bailout procedures.

Robotic segmentectomy commonly begins with systematic inspection of the pleural cavity and assessment for occult dissemination. Hilar dissection is performed with careful identification of the segmental artery, bronchus, and vein. The order of division varies according to the segment and surgeon preference, but each structure should be confirmed against preoperative imaging before transection. Preservation of veins draining the remaining segments is critical because venous congestion can cause infarction, prolonged air leak, or impaired postoperative function. Intersegmental planes may be developed by inflation-deflation, near-infrared fluorescence after intravenous indocyanine green, or a combination of methods. The parenchyma is divided to maintain an adequate margin while minimizing unnecessary tissue loss.

Complexity may require stapled or hand-sewn bronchial techniques, selective arterial reconstruction, extended segmentectomy, or combined resection of a neighboring subsegment. These approaches should be undertaken only when the surgeon can maintain oncologic and technical control. A low threshold for conversion to thoracoscopic or open surgery is appropriate when bleeding cannot be safely controlled, anatomy is unclear, adhesions prevent exposure, or the planned margin is inadequate. Conversion is a safety decision rather than a procedural failure.

Postoperative management includes lung-protective anesthesia, early mobilization, multimodal analgesia, chest-drain assessment, pulmonary hygiene, and prompt treatment of air leak or infection. Relevant outcomes include operative duration, blood loss, conversion rate, length of stay, prolonged air leak, readmission, pulmonary complications, margin status, lymph-node yield, recurrence, and overall survival. Robotic surgery may reduce access trauma and facilitate discharge, but these benefits depend on case selection and team proficiency.

Recent Advances / Emerging Therapies

Recent advances include patient-specific three-dimensional anatomical reconstruction, virtual surgical planning, fluorescence-guided identification of intersegmental planes, and improved robotic stapling and energy devices. These tools can make variant anatomy more understandable and may reduce preventable vessel injury. Artificial intelligence-assisted imaging may eventually improve prediction of segmental anatomy, estimate margin adequacy, and identify radiographic features associated with invasive behavior, although clinical validation and transparent performance assessment remain necessary.

Neoadjuvant immunotherapy or chemoimmunotherapy is increasingly relevant for patients with resectable non-small cell lung cancer at higher risk of recurrence. Such treatment may downstage disease or improve systemic control, but it can also produce fibrosis, inflammatory adhesions, and altered tissue planes that complicate robotic dissection. The decision to perform segmentectomy after systemic therapy should therefore be individualized within a multidisciplinary team. Future research should compare robotic segmentectomy with thoracoscopic segmentectomy and lobectomy using standardized definitions of complexity, margin adequacy, nodal staging, quality of life, cost, and long-term oncologic outcomes.

Guideline Recommendations

Contemporary thoracic oncology guidelines support anatomic segmentectomy as an alternative to lobectomy for selected patients with small, peripheral, node-negative non-small cell lung cancers when an adequate parenchymal margin and systematic nodal evaluation can be achieved. Recommendations generally emphasize careful staging, high-resolution imaging, appropriate pulmonary assessment, and avoidance of sublobar resection when tumor size, central location, aggressive histology, or inadequate margins indicates a higher risk of recurrence. The exact eligibility criteria vary among professional societies and continue to evolve as randomized trial data mature.

Guidelines do not require a robotic approach, because the surgical platform should be chosen according to patient anatomy, surgeon expertise, available resources, and institutional outcomes. Robotic segmentectomy is reasonable when it can provide safe exposure and complete resection without delaying treatment or increasing avoidable risk. Surgeons should document the anatomical rationale, expected margin, nodal strategy, potential need for conversion, and postoperative surveillance plan. Complex cases are best reviewed by thoracic surgeons, radiologists, pulmonologists, medical and radiation oncologists, anesthesiologists, and pathologists.

Conclusion

Robotic segmentectomy offers a sophisticated parenchyma-sparing option for selected patients with anatomically complex pulmonary tumors. Its principal advantages are enhanced visualization, instrument articulation, and the ability to perform meticulous dissection within difficult segmental anatomy. These benefits are clinically meaningful only when paired with accurate staging, adequate margins, systematic nodal assessment, and disciplined management of vascular and bronchial variation. Current evidence is encouraging but remains less mature than the evidence for standard lobectomy and conventional segmentectomy in routine anatomy. Complex robotic procedures should therefore be concentrated in experienced centers with multidisciplinary planning, structured training, and prospective outcome monitoring. As imaging, fluorescence guidance, surgical simulation, and systemic therapy continue to advance, robotic segmentectomy may become increasingly important in balancing oncologic efficacy with long-term preservation of pulmonary function.