Relationship between the pelvic incidence and the modified Oxford Hip score: a computed tomographic analysis

Acta Neurochirurgica (2024) 166:503

There is scant data on the relationship between skeletal maturity and pelvic parameters such as the pelvic incidence (PI). The aim of this study was to report on the relationship between PI and the modified Oxford Hip Score (mOHS) as a measure of skeletal maturity. We hypothesised a significant correlation would be determined between the mOHS and PI.

Methods CT performed for major trauma or abdominal pathology was assessed. The PI and segmental vertebral body angles, L1-L5, were obtained. The mOHS was used to assess maturity with total scores ranging from 16 to 25 (least-most mature). 193 scans were analysed. The mean age 9.7 years (range 4.0 – 15.7); 62 female (32%).

Results There were significant positive correlations between age and all components of the mOHS: FH (r = 0.765; p < 0.001), GT (r = 0.749; p < 0.001), LT (r = 0.704; p < 0.001), TC (r = 0.775; p < 0.001), IL (r = 0.642; p < 0.001) and mOHS (r = 0.811; p < 0.001). Mean PI for the cohort was 40.8 (s.d. 9.1; range 19.3–69.4). There were significant albeit weak correlations with FH (r = 0.213; p = 0.003), GT (r = 0.209; p = 0.004), LT (r = 0.247; p < 0.001), TC (r = 0.263; p = < 0.001), IL (r = 0.221; p = 0.002) and total mOHS (r = 0.255; p < 0.001). Multivariable linear regression indicated TC and LT the best predictors of PI. Significant correlations noted between L1 segmental lordosis and all components of the mOHS, strongest with triradiate (r=-0.406; p < 0.001).

Conclusions In this CT-based study, the mOHS correlated weakly with PI and proximal vertebral body lordosis. Of the mOHS components, triradiate and lesser trochanter cartilage status appeared to be best correlated with PI and may be anatomic variables to focus on in future research.

Posterior fossa ependymomas: new radiological classification with surgical correlation

Childs Nerv Syst (2010) 26:1765–1772. DOI 10.1007/s00381-010-1251-6

The key determinant of long-term outcome in infratentorial ependymomas remains the extent of surgical resection. We describe a new radiological classification system which is validated against surgical findings and correlated with risk of post-operative residual tumour.

Methods Twenty-five consecutive patients (12 females, mean age 4.9 years, range 0.5–17 years) with infratentorial ependymomas were studied. Lesions were classified on preoperative MRI according to the pattern of extension, brainstem displacement and involvement of the obex, as lateral-type or midfloor-type tumours. Twenty-one operative records were reviewed with respect to the microanatomical tumour origin by a paediatric neurosurgeon, blinded to MRI findings. Follow-up imaging studies were evaluated for residual tumour.

Results There were 15 cases of midfloor-type tumour (anterior displacement of brainstem, infiltration of obex) and 10 cases of lateral-type tumour (lateral displacement of brainstem, obex free of tumour). Extension into prepontine or cerebellopontine cisterns was more common in lateraltype tumours. Agreement between the radiological classification and tumour origin, as defined by operative records, was seen in 18 out of 20 cases. Risk of residual tumour in lateral-type tumours was more than twice that of midfloortype tumours (80% vs. 33%, p=0.04). Risk of tumour residual was also significantly higher when vessel encasement or prepontine extension was observed.

Conclusions Infratentorial ependymomas can be preoperatively classified as lateral-type or midfloor-type tumours. This correlates well with operative findings. Lateral-type tumours have significantly increased risk of residual tumour compared to midfloor- type tumours and this may influence intensity of imaging surveillance.