# Analysis of Craniocervical Abnormalities in Osteogenesis Imperfecta during Growth
## 4 Discussion
Thus, in their study sample (54 individuals), they diagnosed 22.2% of the cases of basilar invagination and 11.1% of the cases of platybasia considering +2 SD, although +3 SD would have more reliably reflected basilar impression, which would have reached 13.2-16.6%. For the diagnosis of basilar impression, they proposed a limit of 3 SD above the mean for the [PERSON], [PERSON], and Kovero measurements (10.6 mm, 11.9 mm, and 9.5 mm, respectively). In the case of platybasia and setting the 3 SD limit, the limit value was 146\({}^{\circ}\) for the anterior cranial base angle [35]. According to these criteria, 10 of the 28 patients in the present study present an angle higher than 146\({}^{\circ}\). In accordance with the presented results, in the sample of children with OI, 9 of the 28 (32.14%) can be considered to have a skull base anomaly if we set the cutoff at +3 SD and by comparing the data with the age-matched controls. Of these 28 children with OI, 5 pa \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Author (Year)**} & \multicolumn{4}{c}{**Diagnostic Criteria of Basilar Anomaly in OI**} & \multirow{2}{*}{\
\begin{tabular}{c} **OI** \\ **Anomaly/Total** \\ **\% (Age in Years)** \\ \end{tabular} } \\ \cline{2-6}  &
\begin{tabular}{c} **[PERSON]** \\ **[PERSON]** \\ \end{tabular} & & **[PERSON]** & **[PERSON]** & **[PERSON]** & **[PERSON]** \\ \hline [PERSON] (1997) & & \(>\)5 mm & \(>\)7 mm & & & 10/52 \\
[43] & & & \(>\)5 mm & \(>\)7 mm & & & 19\% \\ \hline [PERSON] (1997) & \(>\)0 mm & \(>\)2.5 mm & \(>\)4.5 mm & & & 18/18 \\
[23] & & & & & 100\% (<\)20) \\ \hline [PERSON] & & & & & 8/47 \\ (1998) [24] & & & & & 17\% (1–15) \\ \[PERSON] (2003) & & \(>\)0 mm & \(>\)0 mm & & & 8/130 \\
[25] & & \(>\)0 mm & \(>\)0 mm & & & 6\% (0–18) \\ \[PERSON] & & & & & 9/42 \\ (2003) [45] & \(>\)0 mm & \(>\)10 mm & & & 21\% (20–69) \\ \[PERSON] (2006) & & & & & 14/54 \\
[35] & \(>\)0 mm & +3 SD & +3 SD & +3 SD & +3 SD & 15\% (16–69) \\ \[PERSON] (2011) [4] & \(>\)0 mm & +3 SD & +3 SD & +3 SD & +3 SD & 41/187 \\ \[PERSON] (2012) [40] & \(>\)0 mm & & +2.5 SD & +2.5 SD & +2.5 SD & 28/76 \\  & & & & & 37\% (0–39) \\ \hline [PERSON] (2014) [42] & \(>\)0 mm & & & +2.5 SD & +2.5 SD & 12/47 \\  & & & & & 26\% (1–19) \\ \hline [PERSON] (2015) [46] & \(>\)0 mm & & & +2.5 SD & +2.5 SD & 13/39 \\  & & & & & 33\% (0–25) \\ \hline Present study & \(>\)0 mm & +2.5 SD & +2.5 SD & +2.5 SD & +2.5 SD & 17/28 \\  & & & & & 60.71\% (6–18) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: List of the limit values proposed by different authors. tients present platybasia, with this being the most common finding, 4 present radiographic signs of basilar impression, and 3 present basilar invagination. In the present study, a lower limit of 2.5 SD is taken as the reference to ensure more sensitive evaluation since in the case of children it is beneficial to identify all the subjects who need a closer follow-up during growth. Following this methodology (+2.5 SD), 17 of the 28 patients with OI (60.71%) can be considered to present an anomaly of the skull base. Of these, 3 patients (10.71%) present basilar invagination, 7 (25%) basilar impression, and 11 (39.29%) platybasia. Based on [PERSON]'s study, years later and in a sample of 187 individuals with OI, [PERSON] [4] found that 22% of them presented an abnormality, with platybasia in 16%, basilar impression in 6%, and basilar invagination in 4%. More recently, with the same diagnostic parameters and in the search for an agreement in the monitoring and the follow-up of skull base anomalies in children with OI, [PERSON] et al. retrospectively studied the data of 94 rx, tomographies, and MRIs; based on the radiographic study, 62% showed platybasia, 11% basilar impression, and 1% basilar invagination [44]. They emphasized the lack of concordance between the diagnostic methods (radiographs and MRIs). Although there is higher diagnostic accuracy when using MRI, they reserved it for confirming the diagnosis of symptomatic cases or when radiographic parameters were abnormal.