Limited pulmonary resection (LPR) is a lung-sparing alternative to lobectomy, designed for small or peripheral lesions. This approach removes cancerous or diseased tissue while preserving as much healthy lung function as possible. The two primary types of LPR are segmentectomy and wedge resection, both used for treating conditions like early-stage Non-Small Cell Lung Cancer (NSCLC). The choice depends on the lesion’s characteristics, the patient’s overall health, and the surgical goal, balancing complete disease removal with preserving respiratory capacity.
Anatomical Differences Between Segmentectomy and Wedge Resection
Wedge resection is a non-anatomical resection because the tissue removed is not defined by the natural sub-units of the lung. This procedure involves cutting a V-shaped piece of lung tissue that includes the lesion and a surrounding margin of healthy parenchyma. The cut is made directly across the lung tissue, often using surgical staplers, without isolating the network of blood vessels and airways. Wedge resection is often faster to perform and associated with a shorter hospital stay and fewer immediate complications.
Segmentectomy, by contrast, is an anatomical resection that follows the defined internal structure of the lung. The lung is divided into lobes, which are further divided into specific bronchopulmonary segments. These segments function as distinct sub-units, each with its own artery, vein, and bronchus. Segmentectomy involves carefully dissecting and dividing the segmental artery, vein, and bronchus leading to the affected segment. This precision allows the surgeon to remove the diseased segment along its natural borders, preserving surrounding healthy segments.
The primary distinction lies in the resection margin and complexity. A wedge resection margin is created by stapling across the lung tissue. A segmentectomy margin is defined by the natural intersegmental plane. Identifying and dividing the bronchovascular structures makes segmentectomy a more technically demanding and time-consuming procedure than a wedge resection.
Clinical Criteria for Surgical Selection
The decision to perform a segmentectomy versus a wedge resection is driven by the patient’s physiological status and the oncological characteristics of the lesion. Wedge resection is frequently used for benign lesions, small peripheral nodules, or as a diagnostic procedure. For confirmed early-stage NSCLC, wedge resection is reserved for patients with significant comorbidities or severely compromised lung function who cannot tolerate the more extensive segmentectomy.
The non-anatomical nature of wedge resection can result in smaller surgical margins and less extensive removal of regional lymph nodes, which is a concern for curative cancer treatment. This procedure may be comparable to segmentectomy for very small tumors, typically those one centimeter or less in size. However, for tumors between one and two centimeters, wedge resection shows lower overall survival and cancer-specific survival rates compared to segmentectomy.
Segmentectomy is the preferred anatomical LPR for early-stage NSCLC, particularly for tumors less than two centimeters, in patients requiring lung preservation with curative intent. This procedure allows for the removal of the lesion along with a more secure margin of healthy tissue and facilitates a more thorough dissection of the regional lymph nodes. Lymph node removal is important for accurate staging and removal of potentially cancerous nodes. Studies show that patients undergoing segmentectomy are more likely to have a greater number of lymph nodes sampled and a larger parenchymal margin than those undergoing wedge resection.
Comparative Postoperative Outcomes
Segmentectomy provides better oncological control for malignant lesions compared to wedge resection, mainly due to wider, more reliable surgical margins and the opportunity for more extensive lymph node sampling. For patients with stage I NSCLC, segmentectomy is associated with significantly better overall survival and cancer-specific survival rates than wedge resection in several large analyses. This survival advantage is notable for tumors larger than two centimeters.
For very small tumors (two centimeters or less), survival and recurrence-free survival outcomes between the two procedures can be comparable, depending on the specific characteristics of the tumor. The risk of local recurrence is lower after segmentectomy because the anatomical approach helps ensure the complete removal of the segment containing the tumor. Wedge resection has been shown to have a higher risk of local recurrence, although some studies suggest no significant difference in recurrence rates.
In terms of functional preservation, wedge resection is less physiologically demanding initially. It is associated with a shorter operative time and a lower rate of overall complications compared to segmentectomy. Recovery of pulmonary function, such as forced expiratory volume in one second (FEV1), is sometimes reported to be better or faster after wedge resection. Despite its complexity, segmentectomy’s precise anatomical removal can result in excellent long-term respiratory outcomes, preserving a high percentage of preoperative lung function.