Evaluating the sagittal spinal and pelvic parameters in Marfan syndrome patients affected by scoliosis

Spinal deformities present a common finding in patients affected with Marfan syndrome (MFS). More specifically, sagittal spine imbalances reflect the typical finding of such deformities. Observing spino-pelvic radiographs, we focused on eliciting any correlation between the pelvic incidence (PI), sacral slope (SS) and thoracolumbar kyphosis measurements, and categorising them according to a sagittal spinal classification system.

One hundred seventy patient records were found over a 6 year period, and further refined to incorporate a total of 44 patients. 25 males and 19 females with an average age of 20 years at imaging. Electronic and hard copies of radiographs were used and measurements were made with virtual Cobb meters, rulers and protractors.

The mean PI was significantly different between type-I (46°) and type-II spines (35°) (p = 0.04), and the values for each class were as follows: type IA-53°, type IB-44°, type IC-36°, type IIA-42°, and type IIB-34°. Type II spines had a lower PI compared to type IA spines (p = 0.037) and to that of an unaffected population. Statistically significant differences were noted in SS between groups (t test; p < 0.001), and ANOVA demonstrated that the largest differences between spinal classes were found in SS.

In our study, PI values were much higher in type I compared to type II spines. Type II spines had PI values as expected, however, had higher than expected SS values. SS followed a down trending pattern across all spinal classes. Type IIA spines had a much greater preponderance for male patients. Overall, we wish to highlight in particular that type II spines were associated with a much lower PI and SS, and report these differences in pelvic morphology and sagittal spine patterns seen in MFS patients. The pelvic tilt and sacral slope parameters observed in our Type II spines may further reflect and characterize the deformity.