Different Technique for bar placement:

The Nuss procedure involves placing steel bars with thoracoscopic assistance. However, when the thoracoscope is positioned in one side of the chest cavity, it becomes challenging to clearly visualize the contralateral side. This limitation may lead to unintended heart injury during the placement of bars, posing a significant threat to the patient's life.

The Wung procedure uses the “Wang Technique” for precise and safe placement of bars. The steps are as follows:

1. A surgical introducer is inserted through an incision on the right lateral chest wall and gradually advanced into the central mediastinal area of the chest cavity.

2. The surgeon’s left index finger is then inserted through an incision on the left lateral chest wall and slowly advanced toward the mediastinum until the fingertip meets the tip of the introducer.

3. Once it is confirmed that no critical structures, such as the heart or major blood vessels, are in contact between the fingertip and the introducer, the tip of the introducer is brought out through the left incision.

4. A guide catheter is then attached to the introducer’s tip, and both the introducer and the guide catheter are withdrawn together through the right chest wall incision, leaving the guide catheter successfully in place within the chest cavity.

5. Following the same approach, the bars are accurately and securely placed into the chest cavity with the assistance of the guide catheter.

This technique not only effectively avoids potential injury to the heart but also eliminates the need for thoracoscopic assistance, significantly reducing the complexity of the procedure while enhancing safety and efficiency.

Different Method of Bar Fixation:

The Nuss procedure utilizes short fixation bars to secure each shaping bar. However, due to the large size of the short fixation bars, they occupy a considerable amount of space. This not only increases the length of the surgical incisions but may also hinder the smooth healing of the incisions post-surgery. In severe cases, it can lead to incision infection, presenting as wound breakdown and pus discharge.

Furthermore, performing this method is technically challenging and makes it difficult to ensure optimal fixation. If the shaping bar is not adequately secured, displacement can occur post-surgery, compromising the effectiveness of the deformity correction.

In contrast, the Wung procedure utilizes steel wires to secure the bars directly onto the ribs，and employs wire guides to place the wires. This method is simpler to perform, provides excellent fixation, and effectively reduces the risk of post-operative displacement of the bars.

Different Corrective Effects:

The Nuss procedure directly utilizes bars to elevate the depression. However, the bony structure of the chest wall in adult patients is generally quite rigid, making direct deformity correction a significant challenge. This not only limits the surgical outcome but also increases the risk of complications such as fractures.

The Wung surgery first performs “pre-shaping” on the chest wall bones before implementing the bar shaping. With various surgical instruments and techniques, the bones in the depressed area are “softened” to improve its plasticity, and the depressed chest wall is lifted to the normal position in advance. This step facilitates the precise shaping of the bars, ensuring excellent corrective results and effectively reducing the risk of complications.

References:

1. https://www.researchgate.net/publication/362042519_Wung_procedure_A_minimally_invasive_operation_for_pectus_excavatum

   
   

2. https://www.casereportsofsurgery.com/article/41/4-2-3-742.pdf