The advent of the Covid-19 pandemic made it necessary to reorganize the services provided by healthcare facilities, aiming for effective and adequate services given the unavailability of resources. This study aims to evaluate the impact of the actions introduced by the Cardarelli hospital in Naples (Italy) to deal with the health emergency due to Covid-19. The parameter mainly analyzed, as an indicator of the performance of surgery hospital department, is the length of stay (LOS) of patients hospitalized both in 2020 (during the pandemic) and in 2019 (before the pandemic). To perform the comparison between the two years of interest, the DMAIC cycle of the Lean Six Sigma methodology was used, employing Jamovi as a statistical tool for the analysis. Associated with a reduction in the number of hospitalizations there is also an increase in the average LOS, with statistically significant differences: for the total number of patients, both men and women over and under 65 years of age, for women without comorbidity and for urgent and scheduled admissions. Of note is the large increase in LOS variability for urgent hospitalizations, which sees the standard deviation almost tripling.