Overview
Definition:
Port mapping in minimally invasive thoracic surgery refers to the strategic planning and placement of surgical ports (incisions for instruments and cameras) to optimize visualization, instrument triangulation, and operative efficiency
It involves understanding critical anatomical landmarks and predicting the optimal angles of approach for various thoracic procedures.
Epidemiology:
Minimally invasive thoracic surgery, including Video-Assisted Thoracoscopic Surgery (VATS), is increasingly adopted worldwide for a wide range of thoracic pathologies
The incidence of thoracic procedures performed via MIS approaches continues to rise, necessitating standardized and efficient port placement techniques.
Clinical Significance:
Effective port mapping is crucial for successful thoracic MIS
It directly impacts operative time, risk of complications (e.g., bleeding, organ injury), patient recovery, and overall surgical outcomes
Proper planning enhances ergonomics for the surgeon and improves access to target pathologies while minimizing iatrogenic trauma.
Indications For Mis Thoracic Surgery
Common Indications:
Resection of lung nodules/masses
Lobectomy/bilobectomy for lung cancer
Pleural procedures (pleurodesis, decortication)
Management of pneumothorax
Thymectomy for myasthenia gravis
Esophageal resection for cancer
Mediastinal mass excision.
Patient Selection Criteria:
Generally suitable for patients with early-stage lung cancer
Absence of extensive pleural disease or dense adhesions
Adequate cardiopulmonary reserve
Patient preference for minimally invasive approach.
Contraindications:
Hemodynamic instability
Severe coagulopathy
Extensive adhesions from previous surgery or infection
Significant empyema
Need for extensive mediastinal lymphadenectomy that is difficult via MIS
Patient refusal or inability to tolerate one-lung ventilation.
Port Placement Principles
Triangulation:
The concept of creating a triangular working space between the camera port and instrument ports
This allows for optimal instrument manipulation and counter-traction, facilitating dissection and suture placement.
Ergonomics And Access:
Ports should be placed to allow comfortable surgeon positioning and unimpeded instrument movement
Access to the target pathology should be direct and without excessive crossing of instruments.
Anatomic Landmarks:
Utilizing bony landmarks (ribs, intercostal spaces) and palpable thoracic structures to guide port placement
Understanding the trajectory to vital structures (lung, pleura, pericardium, diaphragm).
Number And Size Of Ports:
Typically 3-5 ports are used
Port sizes range from 5mm to 12mm depending on the instruments and the need for specimen extraction
The number of ports is minimized while ensuring adequate surgical control.
Port Mapping Strategies
Standard Vats Port Placement:
For a standard left lung lobectomy, common ports include: Camera port (typically 4th or 5th intercostal space, anterior axillary line)
Working port 1 (typically 7th or 8th intercostal space, posterior to camera port)
Working port 2 (typically 4th or 5th intercostal space, posterior to camera port).
Anterior Approach Port Placement:
Often used for anterior lesions or access to superior mediastinal structures
Ports are placed more anteriorly, typically along the mid-clavicular or anterior axillary lines.
Posterior Approach Port Placement:
Favored for posterior lesions or access to the diaphragmatic surface
Ports are positioned along the posterior axillary or scapular lines.
Single Port Vats:
Utilizes a single incision (typically 3-4 cm) through which a specialized port is placed, allowing for insertion of the camera and instruments
Requires advanced skill and specific port systems.
Hybrid Vats:
Combines a small anterior thoracotomy (e.g., 5-6 cm) for instrument passage with a camera port placed elsewhere
Useful for situations requiring manual retraction or larger specimen extraction.
Preoperative Planning And Imaging
Role Of Imaging:
CT scans (with contrast) are essential for defining lesion location, size, relationship to surrounding structures, and planning port placement
3D reconstructions can further aid visualization of critical anatomy.
Ct Based Port Planning:
Correlating imaging findings with the patient's chest wall anatomy
Projecting optimal port trajectories onto the skin based on CT slice analysis.
Preoperative Discussion:
Discussing the planned port configuration with the surgical team, including the assistant surgeon and scrub nurse
Anticipating potential challenges and modifications.
Intraoperative Considerations And Modifications
Intraoperative Assessment:
Initial inspection of the pleural cavity to confirm findings, assess adhesions, and refine port placement if necessary
Direct visualization may alter the planned port locations.
Adapting To Anatomy:
Flexibility in port placement is key
If initial ports do not provide adequate access or visualization, additional ports or repositioning of existing ones may be required.
Managing Adhesions:
Dense adhesions may necessitate additional working ports or conversion to a larger incision for safe dissection
Careful planning and gentle dissection are paramount.
Specimen Extraction:
Planning for a port site large enough for specimen retrieval, often utilizing a protective retrieval bag to prevent tumor cell dissemination or contamination.
Key Points
Exam Focus:
Understanding the principles of triangulation and ergonomics is critical for VATS
Common port sites for standard procedures (lobectomy) and their rationale are frequently tested
Single-port and hybrid VATS techniques are also important areas of focus.
Clinical Pearls:
Always perform a systematic preoperative planning using CT scans
Be prepared to modify port placement intraoperatively based on findings
Minimize the number of ports to reduce morbidity
Use a retrieval bag for all resected specimens, especially malignant ones.
Common Mistakes:
Placing ports too close together, leading to instrument collision
Inadequate visualization due to poor port angles
Neglecting to plan for specimen extraction
Failure to anticipate and manage adhesions, leading to conversion.