Pelvic imbalance and leg length discrepancy in Marfan scoliosis

Scoliosis is the most common spinal deformity in Marfan Syndrome. Its morphology is well investigated in the patient’s physical examination; on the contrary, the pelvic parameters and leg length discrepancy (LLD) are often neglected. In previous studies, a strong statistical correlation had already been highlighted between curvature anomalies in the sagittal plane and a reduction in the sacral slope and pelvic incidence compared to the healthy population. The Ghent diagnostic criteria showed some gaps, which is why it will be necessary to develop new algorithms. In our opinion, pelvic parameters should be added to the definition of the type of scoliosis, according to Sponseller’s classification, both for an improvement of the diagnostic picture and for a more correct surgical planning. The same goes for LLD, since once rebalanced, the patient would have the ability to self-balance the differences in length and contain the progression of scoliosis. METHODS: This study took into account 54 young patients (under 30 years old) with Marfan Syndrome, who came for a medical examination at our clinic in Pavia, Italy, between 2017 and 2019. The inclusion criteria were a pathogenic mutation in the FBN1 gene, scoliosis with Cobb angle >10°, no previous spinal surgery and LLD. Spine X-rays were taken antero-posteriorly and laterally. RESULTS: The mean Cobb X-ray values in the simple antero-posterior view of the spine were 24.97° for the lumbar curves, 25.16° for the dorsal curves, and 27.73° for the dorsal-lumbar curves. In our series, the mean lumbar lordosis was 44°, compared with 59.6° in the general population. On the other hand, the calculated mean dorsal kyphosis in our patient group is 53.79°, compared with 45°, which is considered the cut-off value for hyperkyphosis in healthy subjects. In the healthy population, the average sacral slope is 40.6°, while in our series the average value was 29.09°, data that agree with the literature. In the healthy population, the average pelvic incidence is 51.4°, while in our series the average value was 33.29°, data that agree with the literature. The mean LLD was 1.1 cm, with a prevalence of the right lower limb as the longest limb. CONCLUSIONS: Even though the life expectancy of patients with Marfan Syndrome has increased, it would be superficial to only deal with severe complications. The treatment of orthopedic morbidity, especially in terms of prevention, deserves more attention. It is necessary to intervene, as far as possible, in the pediatric age, considering that the growth patterns of patients with Marfan Syndrome are abnormal and uncoordinated, not just trivially in excess. Focusing on maintaining good sagittal balance and containing LLD could be a good strategy.