Statistical analysis
Data were collected during hospital stay and by outpatient services, and were put together in an Excel document. By using SPSS 17.0, the data were analysed through a retrospective method. The data for continuous variables were expressed as mean ± SD or as ranges. Value changes from pre- to postoperative were compared using the Wilcoxon test for paired samples. Significance was defined with a P-value of ≤ 0.05.