Minimally invasive repair of pectus excavatum by the Nuss procedure: The learning curve

Objectives: To define the learning process of minimally invasive repair of pectus excavatum by the Nuss procedure through assessment of consecutive procedural metrics. Methods: A single-center retrospective observational cohort study was conducted of all consecutive Nuss procedures performed by individual surgeons without previous experience between June 2006 and December 2018. Surgeons were proctored during their initial 10 procedures. The learning process after the proctoring period was evaluated using nonrisk-adjusted cumulative sum (ie, observed minus expected) failure charts of complications. An acceptable and unacceptable complication rate of 10% and 20% were used. Logarithmic trend lines were used to assess over-time performance regarding operation time. Results: Two-hundred twenty-two consecutive Nuss procedures by 3 general thoracic surgeons were evaluated. Cumulative sum charts showed an average performance from the first procedure after being proctored onward for all surgeons, whereas surgeon B demonstrated a statistically significant complication rate equal to or less than 10% after 59 cases. Post-hoc sensitivity analyses using a stricter acceptable and unacceptable complication rate of 6% and 12% also showed an average performance for all surgeons. Although, the median time between consecutive procedures ranged from 7 to 35 days, no frequency-outcome relationship was observed. In addition, surgeons required the same average operation time throughout their entire experience. Conclusions: After a 10-procedure proctoring period, repair of pectus excavatum by the Nuss procedure is a safe procedure to adopt and perform without a typical (complication based) learning curve while performing at least 1 procedure per 35 days.