Limitations
The present study has several limitations. First, as a single site study, the conclusion may not be applicable in general because of difference in practice patterns. Second, patients were not randomly assigned to either group. Therefore, selection bias may affect our findings. To mitigate the effect of this selection bias on outcomes, propensity score matching was used to identify well matched LVD and NLVF patients for comparison. Third, the size of our cohorts are somewhat small for comparison, but the statistical power of the analysis of operative outcomes, which was performed to determine whether there was enough power in this model. Last, incomplete follow up may bias our results when patient who drop out are different from those who complete follow-up. We have minimized this bias by incorporating innovative prevention and retention strategies (such as proactive social media interaction) into our design and implementation. We performed a structured survey by telephone interview in patients who were lost to follow-up to address this issue.