The goal of this clinical trial is to learn whether intraoperative longitude-latitude-depth three-dimensional localization (LLD localization) is non-inferior to preoperative CT-guided percutaneous lung puncture localization for identifying 0.8-2 cm peripheral pulmonary nodules in adults undergoing video-assisted thoracoscopic surgery (VATS)-assisted sublobar resection. It will also evaluate the safety and perioperative effectiveness of the two localization methods. The main questions it aims to answer are:

1. Is the localization accuracy rate of LLD localization non-inferior to that of CT-guided percutaneous lung puncture localization?
2. Does LLD localization improve perioperative outcomes, including localization time, postoperative recovery, pain, quality of life, and perioperative complication rates?

Researchers will compare LLD localization with CT-guided percutaneous lung puncture localization to determine whether LLD localization provides comparable localization accuracy while reducing procedure-related complications and improving perioperative outcomes.

Participants will:

1. Be randomly assigned in a 1:1 ratio to either the LLD localization group or the CT-guided percutaneous lung puncture localization group.
2. Undergo pulmonary nodule localization using the assigned localization method.
3. Receive VATS-assisted sublobar resection following localization.
4. Be assessed for localization accuracy, perioperative complications, localization time, postoperative chest drainage tube removal time, oxygenation index, postoperative hospital stay, pain scores, and quality-of-life outcomes.
5. Complete follow-up assessments at 1, 3, and 6 months after surgery.

Peripheral pulmonary nodules, particularly small subsolid nodules, are increasingly detected due to the widespread use of low-dose computed tomography (CT) screening. Accurate intraoperative identification of these nodules remains challenging during video-assisted thoracoscopic surgery because many lesions are difficult to visualize or palpate after lung collapse. Reliable localization is therefore essential to facilitate precise sublobar resection while preserving healthy lung tissue.

Preoperative CT-guided percutaneous localization techniques are widely used in clinical practice. However, these procedures require additional preoperative intervention and may be associated with complications such as pneumothorax, pulmonary hemorrhage, hemothorax, patient discomfort, and increased procedural complexity. Furthermore, successful localization depends on radiologic resources and coordination between multiple departments.

The longitude-latitude-depth (LLD) localization method is a novel intraoperative three-dimensional localization strategy developed to identify pulmonary nodules using anatomical reference lines and preoperative imaging measurements. The method utilizes the natural longitudinal and transverse landmarks of the collapsed lung together with the measured depth of the target lesion to estimate the spatial location of the nodule during surgery. Because localization is performed intraoperatively without transcutaneous puncture, the technique has the potential to reduce procedure-related trauma and simplify the clinical workflow.

Preliminary clinical experience suggests that the LLD localization method may provide accurate localization while avoiding several limitations associated with preoperative puncture-based approaches. However, high-quality prospective evidence comparing this technique with current standard localization methods remains limited.

This multicenter randomized controlled trial has been designed to provide rigorous clinical evidence regarding the performance of the LLD localization technique. The study will evaluate whether this novel approach can serve as an effective alternative to conventional CT-guided localization and support broader clinical application in the surgical management of peripheral pulmonary nodules.

Inclusion Criteria:

• Clinically diagnosed pulmonary nodule by non-contrast chest CT.

• Age 18 to 80 years.

• Expected survival time of at least 12 months.

• Single peripheral pulmonary nodule with a diameter between 0.8 cm and 2 cm.

• Chest CT characteristics meeting both of the following criteria:

  1. Solid component proportion ≤50%.
  2. Located subpleurally or in the outer one-third of the lung parenchyma.

• Willing to undergo VATS-assisted sublobar resection.

• No contraindications to pulmonary localization procedures or surgery.

• Able to understand the study and willing to sign written informed consent.

Exclusion Criteria:

• Use of other localization methods or other surgical procedures.
• Concurrent participation in another clinical study.
• Pregnancy.
• Unwillingness or inability to cooperate with participation in this study for any reason.

To protect participant privacy and maintain clinical data confidentiality, individual participant data will not be made publicly available.