Is a shorter bar an effective solution to avoid bar dislocation in a Nuss procedure?

Area of Science:

• Thoracic surgery
• Biomechanical engineering
• Pediatric surgery

Background:

• Minimizing bar dislocation in the Nuss procedure is a persistent challenge.
• Previous methods have focused on various expedients to address this issue.

Purpose of the Study:

• To develop a mathematical model for analyzing mechanical stresses on Nuss bars of varying lengths.
• To apply this model to optimize bar length in clinical Nuss procedures.

Main Methods:

• Finite element analysis was employed to model mechanical stresses and define stress cases.
• Patient data were compared between a standard Nuss criteria group (NC) and a model-based suggestion group (MS).
• The MS group used bars significantly shorter than the NC group, based on model-derived recommendations.

Main Results:

• The model-based suggestion group (MS) had a mean bar length of 11.67 inches compared to 14.19 inches in the standard Nuss criteria group (NC).
• Bar dislocation incidence decreased from 10.4% in the NC group to 1.1% in the MS group (odds ratio 0.0989, p = 0.0373).
• Mean operating time was reduced in the MS group (43 minutes) compared to the NC group (57 minutes).

Conclusions:

• Shorter Nuss bars decrease tension at suture points, enhancing stability.
• Reduced tension minimizes the risk of bar flipping and dislocation.
• Implementing shorter Nuss bars, guided by biomechanical modeling, can lower the incidence of bar dislocation in Nuss procedures.