## 3 Results  
Table 2 shows the vibration sensation and monofilament test values and the temperature of the big toe before and after CO\({}_{2}\) or placebo treatments. Results show that before the treatment, the mean values of vibration sensation, monofilament test and big toe temperature were comparable between the groups (\(p_{\text{ vibration}}\)\({}^{\text{ac}}\)= 0.841; \(p_{\text{ monofilament}}\)\({}^{\text{ac}}\)= 0.127; \(p_{\text{ temperature}}\)\({}^{\text{ac}}\)= 0.415). \begin{table}
\begin{tabular}{c c c c} \hline  & **Study Group** & **Control Group** & \(p\) \\ \hline No. of patients & 30 (24 M, 6 F) & 30 (24 M, 6 F) & 1.000 \\ Average age of patients (years \(\pm\) SD) & 65.3 \(\pm\) 11.9 & 66.76\(\pm\) 10.6 & 0.640 \\ BMI (mean kg/m\({}^{2}\)\(\pm\) SD) & 29.85 \(\pm\) 5.0 & 30.2 \(\pm\) 4.9 & 0.756 \\ Tobacco smokers yes/no & 4/26 & 3/27 & 1.000 \\ HbA1c before therapy (mean)\({}^{\text{ac}}\)\(\pm\) SD) & 7.08 \(\pm\) 0.85 & 7.00 \(\pm\) 0.90 & 0.736 \\ Diabetes mellitus type (type 1/type 2) & 1/29 & 2/28 & 0.999 \\ Average score on Michigan neuropathy scoring instrument (score \(\pm\) SD) & 8.23 \(\pm\) 2.61 & 8.67 \(\pm\) 2.55 & 0.518 \\ \hline \end{tabular}
\end{table} 
Table 1: Basic characteristics of the study and the control groups. \begin{table}
\begin{tabular}{c c c c c} \hline  & **Study Group** (N = 30) & \multicolumn{3}{c}{**Control Group** (N = 30)} \\ \hline \multirow{4}{*}{Vibration sensation score} & Before CO\({}_{2}\) & After CO\({}_{2}\) & Before placebo & After placebo \\  & Therapies\({}^{\text{\text{\text@underline{a}}}}\) & Therapies\({}^{\text{\text{\text@underline{b}}}}\) & treatment\({}^{\text{\text{\text@underline{c}}}}\) & Treatment\({}^{\text{\text{\text@underline{d}}}}\) \\ \cline{2-5}  & 5.467 \(\pm\) 2.573 & 2.583 \(\pm\) 2.173 & 5.333 \(\pm\) 2.537 & 4.867 \(\pm\) 2.596 \\ \cline{2-5}  & \(p\) vibration\({}^{\text{ab}}\) & \(<\) 0.001 & \(\pm\) 0.9 vibration\({}^{\text{cd}}\) & \(<\) 0.242 \\ \cline{2-5}  & \(p\) monofilament\({}^{\text{ab}}\) & \(<\) 0.001 & \(p\) monofilament\({}^{\text{cd}}\) & \(<\) 0.484 \\ \cline{2-5}  & 26.277 \(\pm\) 2.875 & 30.651 \(\pm\) 1.611 & 26.882 \(\pm\) 2.828 & 27.263 \(\pm\) 2.968 \\ \cline{2-5}  & \(p\) temperature\({}^{\text{ab}}\) & \(<\) 0.001 & \(p\) temperature\({}^{\text{cd}}\) & \(<\) 0.612 \\ \hline \end{tabular}
\end{table} 
Table 2: Vibration sensation, monofilament test and temperature of the big toe before and after treatment in both legs for the study and control groups (\({}^{\text{\text@underline{a}}}\) study group before therapy, \({}^{\text{\text{\text@underline{b}}}}\) study group after therapy, \({}^{\text{\text{\text@underline{c}}}}\) control group before therapy, \({}^{\text{\text{\text@underline{d}}}}\) control group after therapy). Vibration, monofilament sensation, and the big toe temperature improved significantly in the study group (see \(p\) vibration \({}^{\text{ab}}\), \(p\) monofilament \({}^{\text{ab}}\) and \(p\) temperature \({}^{\text{ab}}\)), but not in the control group (see \(p\) vibration \({}^{\text{cd}}\), \(p\) monofilament \({}^{\text{cd}}\) and \(p\) temperature \({}^{\text{cd}}\)). After the treatment, the vibration sensation, monofilament test and toe temperature between the groups differed significantly (\(p\) vibration \({}^{\text{bd}}\) = 0.001; \(p\) monofilament \({}^{\text{bd}}\) < 0.001; \(p\) temperature \({}^{\text{bd}}\) < 0.001). No significant differences were noted in measured parameters between the leg with a chronic wound and the contralateral leg before or after the CO\({}_{2}\) therapy. Improvement in vibration sensation, monofilament test, and temperature of the big toe after CO\({}_{2}\) therapy was comparable in the leg with a chronic wound and in the contralateral leg without a wound (Figures 1-3). There was no difference in the observed parameters in any leg in the control group (Figures 1-3).