Double-bar application decreases postoperative pain after the Nuss procedure.

Objective: This biomechanical study aims to elucidate whether additional bar application increases postoperative pain after the Nuss procedure for pectus excavatum.

Methods: Clinical evaluation: The intensity of postoperative pain was compared between patients for whom a single-bar was used (single-bar group: n = 14) and those for whom double bars (double-bar group: n = 10) were used to correct the thoracic deformity. The evaluation was performed by referring to the frequency with which local anesthetics were self-injected in a patient-controlled anesthetic system and how many days were needed for the patients to resume ambulation. Theoretical evaluation: An original simulation system for the Nuss procedure was developed by producing 3-dimensional finite element analysis models from computed tomographic data of patients with pectus excavatum. With this system, single-bar and double-bar placement was simulated separately for the thorax models of the double-bar group. The stresses occurring on the thoraces were then compared between the two situations.

Results: Clinical evaluation: Self-injection of local anesthetic was more frequent for the single-bar group than for the double-bar group; single-bar patients restarted ambulation later than the double-bar group. Theoretical evaluation: Stresses on the thoraces were smaller when double bars were applied than when a single bar was applied.

Conclusions: Performing double-bar placement decreases postoperative pain. Therefore, surgeons should not hesitate to perform double-bar correction in patients in whom the deformity extends to multiple intercostal spaces, requiring correction of the thorax shape at multiple sites.