Learning Curve Analysis of Open Kasai Portoenterostomy for Biliary Atresia

Open Kasai portoenterostomy (KPE) remains the mainstay of treatment for biliary atresia (BA) even in the era of minimally invasive surgery and is generally considered to be technically challenging. This study describes the learning curve (LC) of open KPE and its effect on outcomes.

In our center, the caseload of BA was relatively low with average annual caseload below five in the past, and open KPE was started in the early 2000s. This study retrospectively enrolled the first 35 consecutive children undergoing open KPE for BA by the same surgeon in our center between June 2003 and April 2014. The LC was evaluated using the cumulative sum (CUSUM) method for operative time (OT).

The CUSUM LC of OT, which peaked at the 23rd case, was best modeled as a second-order polynomial with equation CUSUM (min) = -0.8851 × case number² + 33.54 × case number -45.978 (R² = 0.7287). The LC consisted of two distinct phases: phase 1 (the initial 23 cases), representing the initial learning phase and phase 2 (the remaining 12 cases), representing acquisition of technical competency. Preoperative parameters were comparable between the two phases (each P > 0.05). Of note, OT and estimated blood loss significantly decreased in phase 2 compared with phase 1 (P < 0.001; P < 0.001, respectively). Furthermore, the rates of early jaundice clearance and 2-y native liver survival significantly increased in phase 2 (P = 0.032; P = 0.034, respectively).

The two phases identified by CUSUM analysis of OT represents characteristic stages of LC for open KPE of the surgeon in our center. It is possible for surgeons to achieve competency of this demanding technique in centers with relatively low caseload of BA and late start of KPE.