Overview
Definition:
Anatomical lung segmentectomy is a lung resection procedure that involves the surgical removal of one or more pulmonary segments based on their defined anatomical vascular and bronchial supply
This approach preserves more lung parenchyma compared to lobectomy or pneumonectomy, offering a potential balance between oncological efficacy and functional lung preservation
It is a technically demanding procedure requiring precise knowledge of segmental anatomy.
Epidemiology:
Segmentectomy is increasingly employed for early-stage non-small cell lung cancer (NSCLC), particularly in patients with compromised pulmonary function, elderly individuals, or those with solitary pulmonary nodules
Its use is also expanding for benign lung lesions and as an alternative to wedge resection for certain malignant conditions where complete oncological clearance with parenchymal sparing is desired
Incidence varies by region and adherence to oncological guidelines.
Clinical Significance:
For DNB and NEET SS surgical examinations, understanding anatomical segmentectomy is crucial for several reasons
It represents an advanced thoracic surgical technique, vital for managing lung malignancies in patients who may not tolerate major resections
Proficiency in this area demonstrates a surgeon's grasp of complex anatomy and minimally invasive techniques
It is frequently tested in conceptual questions, case-based scenarios, and viva voce examinations related to lung cancer management and pulmonary surgery.
Indications
Oncological Indications:
Primary early-stage NSCLC (T1a or T1b N0 M0) with <2 cm tumor size and ground-glass opacity components, especially in patients with poor pulmonary reserve or comorbidities contraindicating lobectomy
Recurrence or new primary lung cancer in a patient who has previously undergone lobectomy or pneumonectomy
Solitary pulmonary nodules suspicious for malignancy that are amenable to segmental resection
Metastatic disease to the lung where a segmentectomy can achieve complete resection.
Benign Indications:
Recurrent pneumonia in a specific segment leading to bronchiectasis or abscess formation
Arteriovenous malformations (AVMs) or pulmonary arteriovenous fistulas (PAVs) located within a segment
Certain primary lung tumors (e.g., hamartomas, adenomas) that require complete excision with adequate margins
Congenital abnormalities like sequestration or bronchogenic cysts involving a segment.
Patient Selection Criteria:
Adequate pulmonary function (e.g., FEV1 > 50% predicted, though segmentectomy can be considered with lower values than lobectomy)
Absence of mediastinal lymphadenopathy (cN0)
No evidence of distant metastasis (M0)
Patients who are poor candidates for lobectomy due to age, comorbidities, or significantly reduced pulmonary function
Precise knowledge of tumor location relative to segmental boundaries.
Contraindications:
Tumors involving multiple segments or the hilum
Tumors with mediastinal lymph node involvement (cN1 or cN2)
Tumors with pleural or chest wall invasion
Diffuse metastatic disease
Patients with extremely poor pulmonary function (e.g., FEV1 < 30% predicted, though this is relative and depends on other factors)
Absence of clear segmental vascular and bronchial supply, making the dissection impossible.
Preoperative Preparation
Imaging Evaluation:
High-resolution CT scan with intravenous contrast is essential for precise anatomical mapping of segmental bronchi, arteries, and veins
3D reconstruction of CT scans can greatly aid in surgical planning
PET-CT scan for staging to rule out distant metastasis
Pulmonary function tests (PFTs) including spirometry, DLCO, and arterial blood gas analysis to assess respiratory reserve
Bronchoscopy for direct visualization of the airway and biopsy if indicated.
Bronchial Anatomy Assessment:
Detailed review of CT images to identify the specific segmental bronchus and its origin from the lobar bronchus
Understanding variations in bronchial anatomy is critical
The right lung has 10 segments (3 in the upper lobe, 2 in the middle, 5 in the lower lobe)
The left lung has 8 segments (4 in the upper lobe - lingula is part of superior segment, 4 in the lower lobe).
Vascular Anatomy Assessment:
Careful assessment of the segmental arteries and veins and their branching patterns
Identification of the segmental artery originating from the lobar artery and the corresponding segmental veins draining into the intersegmental veins or directly into the pulmonary veins
Left lung segmental vessels can be more complex due to the oblique fissure.
Patient Optimization:
Smoking cessation at least 4-6 weeks prior to surgery
Management of cardiopulmonary comorbidities
Nutritional assessment and optimization
Physiotherapy and breathing exercises
Antibiotic prophylaxis according to institutional guidelines.
Procedure Steps
Approach:
Can be performed via open thoracotomy or minimally invasively using Video-Assisted Thoracic Surgery (VATS) or robotic-assisted thoracic surgery (RATS)
VATS/RATS is preferred for early-stage tumors and eligible patients due to reduced invasiveness, shorter hospital stay, and faster recovery.
Identification And Dissection:
The key is to identify the correct segmental bronchus, artery, and vein
Dissection is performed along the intersegmental plane, ideally defined by an avascular plane or an accumulation of air or fluid if the segment is inflated or collapsed
The bronchus is typically divided first, followed by the artery and veins
Identifying the segmental bronchus and its corresponding artery and veins is paramount.
Division Of Structures:
Bronchus: Dissect the segmental bronchus and divide it using an endoscopic stapler or ligation
Artery: Identify and ligate or staple the segmental artery
Veins: Identify and ligate or staple the segmental veins, which may be multiple and drain into the main pulmonary veins
Careful attention to hemostasis is critical throughout.
Parenchymal Division And Stapling:
After division of vascular and bronchial structures, the remaining lung parenchyma is divided along the intersegmental septum using an endoscopic stapler
The stapler line should be placed away from the remaining segmental bronchus to ensure adequate margins
Air leaks are managed with reinforced stapling or sutures.
Air Leak Management And Drainage:
Thorough inspection for air leaks
Reinforcement of the staple line if necessary, often with buttresses
Placement of chest tubes for drainage and monitoring of air leak
Hemostasis confirmed before closure.
Postoperative Care
Pain Management:
Multimodal pain management including patient-controlled analgesia (PCA), epidural anesthesia, or intercostal nerve blocks
Regular assessment of pain scores and timely administration of analgesics
Early mobilization is encouraged.
Respiratory Care:
Incentive spirometry, deep breathing exercises, and chest physiotherapy to prevent atelectasis and pneumonia
Monitoring of oxygen saturation and arterial blood gases
Early removal of chest tubes once air leak ceases and drainage is minimal
Pulmonary rehabilitation as needed.
Monitoring For Complications:
Close monitoring for persistent air leak, hemothorax, chylothorax, infection (empyema), bronchopleural fistula, and cardiovascular complications
Regular chest X-rays to assess lung expansion and pleural effusion
Vital sign monitoring.
Discharge Criteria:
Patient able to tolerate oral intake and ambulate
Minimal or no air leak from chest tube
Pain well-controlled with oral analgesics
Absence of significant fever or signs of infection
Adequate respiratory status for discharge.
Complications
Early Complications:
Persistent air leak (most common, incidence 5-20%)
Hemothorax or bleeding
Pleural effusion or empyema
Pneumonia
Atelectasis
Bronchospasm
Injury to adjacent structures.
Late Complications:
Chronic air leak
Bronchopleural fistula (rare)
Respiratory insufficiency due to loss of lung function
Tumor recurrence or metastasis
Intersegmental dehiscence or herniation.
Prevention Strategies:
Meticulous surgical technique with precise dissection and division of bronchi, arteries, and veins
Careful identification of segmental planes
Use of reinforced staplers and buttresses for staple lines
Adequate hemostasis
Thorough intraoperative air leak testing
Postoperative respiratory physiotherapy and early mobilization
Careful patient selection and optimization
Ensuring oncological margins are adequate.
Key Points
Exam Focus:
Anatomical segmentectomy requires precise knowledge of lung segmental anatomy (bronchial and vascular supply)
Differentiate segmentectomy from lobectomy and wedge resection in terms of oncological control and lung preservation
Key indications in early-stage NSCLC and in patients with poor pulmonary reserve
Common complications and their management
VATS/RATS approach for segmentectomy.
Clinical Pearls:
When dissecting in the fissure, remember that the arteries and veins often lie on either side of the segmental bronchus
The intersegmental veins are key landmarks for identifying segmental boundaries, especially in VATS
Always confirm adequate margins intraoperatively if possible, or plan for frozen section analysis
Be prepared for anatomical variations.
Common Mistakes:
Incomplete understanding of segmental anatomy leading to imprecise resection
Inadequate margins, especially for malignant lesions
Failure to identify and control all segmental vessels, leading to bleeding
Injudicious stapling of bronchi or vessels
Underestimating the risk of air leak, particularly in the elderly or those with underlying lung disease
Not performing adequate oncological staging preoperatively.