# Using Virtual Reality Simulators to Enhance Laparoscopic Cholecystectomy Skills Learning
## 3 Results
### Meta-Analysis
The I\({}^{2}\) value is 86%, indicating substantial heterogeneity. It was noted that [PERSON] et al. (2013) seemed to be an outlier. It emphasized the better accessibility and availability of simple \"take-home\" box trainers over VR simulators and reached the conclusion that \"take-home\" box trainers are an effective alternative to VR simulators. However, the experiment design and condition do not align with the rest of the studies in the forest plot. Thus, we again explored the effects of excluding it. The WMD increased to 3.41 with 95% confidence intervals (CI) of 2.39 and 4.43. The heterogeneity is significantly lower (I\({}^{2}\) = 53%) (see Table 5). We further explored the sensitivity of evaluation methods (Table 6) as well as the difference in score improvement for the students subgroup vs. the residents subgroup (Table 6). It was noted that all evaluation methods can successfully demonstrate the performance improvement after VRT. The OSATS seemed to be more descriptive and consistent, with high WMD and lower heterogeneity (I\({}^{2}\) = 9%). For participants with different levels of experience, the students subgroup consistently achieved greater improvement in scores (4.19 vs. 3.16), and the heterogeneity is 9% compared to 83% in the residents subgroup. It seemed to indicate that the greater improvement in time-to-completion for the residents subgroup was mostly due to better proficiency. The students' subgroup benefited more greatly from VRT in terms of skills (scores). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Intervention**} & \multicolumn{3}{c}{**Control**} & \multicolumn{3}{c}{**Mean Difference**} & **Weight** & **Mean Difference** \\ \hline
**Study** & **Mean** & **S.D.** & **N** & **Mean** & **S.D.** & **N** & **IVhet, 95\% CI** & **(\%)** & **IVhet, 95\% CI** \\ \hline Students subgroup & & & & & & & & & & \\ [PERSON] et al. (2017) & 0.80 & 0.49 & 20 & 1.00 & 0.55 & 20 & \(-\)0.20 [\(-\)0.53, 0.12] & 5.51 & & \\ [PERSON] et al. (2013) [37] & 0.80 & 0.21 & 10 & 1.00 & 0.23 & 10 & \(-\)0.20 [\(-\)0.39, 0.00] & 15.09 & & \\ Subtotal & & & 30 & & 30 & \(-\)0.20 [\(-\)0.37, \(-\)0.03] & 20.60 & & & \\  & & \multicolumn{3}{c}{Heterogeneity: Q = 0.00, \(p\) = 0.97, \(\Gamma^{2}\) = 0\%} & & & & & & \\ \hline Residents subgroup & & & & & & & & & & \\ [PERSON] et al. (2011) & 0.73 & 0.31 & 33 & 1.00 & 0.40 & 31 & \(-\)0.27 [\(-\)0.45, \(-\)0.10] & 18.48 & & \\ [PERSON] et al. (2014) & 0.95 & 0.56 & 7 & 1.00 & 0.55 & 7 & \(-\)0.05 [\(-\)0.63, 0.53] & 1.73 & & \\ [PERSON] et al. (2016) & 0.76 & 0.34 & 107 & 1.00 & 0.38 & 81 & \(-\)0.24 [\(-\)0.35, \(-\)0.14] & 52.69 & & \\ [PERSON] et al. (2015) & 0.70 & 0.22 & 8 & 1.00 & 0.27 & 8 & \(-\)0.30 [\(-\)0.60, \(-\)0.15] & 6.50 & & \\ Subtotal & & & 155 & & 127 & \(-\)0.25 [\(-\)0.34, \(-\)0.16] & 79.40 & & & \\  & & \multicolumn{3}{c}{Heterogeneity: Q = 0.65, \(p\) = 0.89, \(\Gamma^{2}\) = 0\%} & & & & & & \\ \hline Overall & & & 185 & 157 & \(-\)0.24 [\(-\)0.32, \(-\)0.16] & 100.00 & & & & \\  & & \multicolumn{3}{c}{Heterogeneity: Q = 0.94, \(p\) = 0.97, \(\Gamma^{2}\) = 0\%} & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Forest plot for the time to completion of task: students vs. residents. A comparison of outcomes of different VR simulators is presented in Tables 6 and 7. The differences in the outcomes of VR simulators are reasonably small. LAP Mentor and LAP Sim are the most widely used simulation systems and seem to provide consistent and slightly better outcomes.