Predictive Physical Manifestations for Progression of Scoliosis in Marfan Syndrome

Yuki Taniguchi, MD, PhD; Yoshitaka Matsubayashi, MD; So Kato, MD, PhD; Toru Doi, MD, PhD; Norifumi Takeda, MD, PhD; Hiroki Yagi, MD, PhD; Ryo Inuzuka, MD, PhD; Yasushi Oshima, MD, PhD; Sakae Tanaka, MD, PhD

Disclosures

Spine. 2021;46(15):1020-1025. 

In This Article

Discussion

The present study provides two novel pieces of information. First, this study demonstrated the accurate prevalence of each physical feature in Japanese patients with Marfan syndrome, and especially the distribution of the severity of scoliosis. Second, this study identified the predictive factors for the progression of scoliosis in Marfan syndrome.

A few studies have investigated the prevalence of physical features in patients with Marfan syndrome.[5,21–26] For most of the physical features analyzed in the present study, the prevalence was equivalent to that reported in previous studies, although the reported prevalence among the previous studies was unacceptably variable in some items. Regarding chest deformity, the prevalence was 64.1% in the present study, while the reported prevalence was from 25% to 69.8%.[5,21–24] In addition, the reported prevalence of severe pes planus with hindfoot deformity ranged from 21.2% to 68.8%, for pneumothorax from 7% to 24%, for dural ectasia from 27.5% to 92%, for protrusio acetabuli from 23% to 62.9%, for contracture of the elbow joint from 2% to 18.8%, for scoliosis from 15% to 100%, and for skin striae from 47% to 76%, all of which were consistent with the results of the present study[5,21–27] (Figure 1).

The distribution of scoliosis severity in Marfan syndrome was demonstrated in the present study. Although the present study is cross-sectional, a high proportion of severe scoliosis in the studied population indicated that spinal deformity in Marfan syndrome is prone to progression (Table 2). This result is consistent with the previous report that identified Marfan syndrome as the most common diagnosis among patients with syndromic scoliosis undergoing spinal deformity correction.[28] The fact that scoliosis is more likely to progress in Marfan syndrome convinced us of the importance of an early intervention for spinal deformity by identifying patients with high risk for progression.

The present study identified the risk factors for progression of scoliosis in Marfan syndrome, which included female sex and a positive wrist sign. It is well known that severe curves are much more frequently found in female patients than in male patients with adolescent idiopathic scoliosis; however, further elucidation is needed to know whether this is just a coincidence or if this can be explained by an unknown female-specific factor.[29]

The wrist sign and the thumb sign both represent the characteristic arachnodactyly in patients with Marfan syndrome, although only positive wrist signs proved to be a risk factor for progression of scoliosis in Marfan syndrome in the present study. This discrepancy may be due to the different meanings of these two signs. The thumb sign is judged positive when the entire distal phalanx of the maximally adducted thumb extends beyond the ulnar border of the palm with or without the assistance of the examiner; thus, it can also represent an element of joint laxity.[9] The wrist sign is designated positive when the tip of the thumb covers the entire fingernail of the fifth finger when wrapped around the contralateral wrist; therefore, it may represent the characteristic slender and skinny skeletal phenotype of this disease more specifically.[9] Hence, this result may suggest that progression of spinal deformity into the severe state in Marfan syndrome may be associated with reduced muscle volume rather than the joint laxity, both of which are the characteristic physical features in Marfan syndrome, but this hypothesis needs further investigation.[30]

Although physical manifestations can change during the growth periods, the prevalence of the wrist sign in Marfan syndrome was reported to increase only until 9 years of age and remained stable thereafter, indicating that the judgment of the wrist sign rarely changes after 10 years of age.[31] Because scoliosis deteriorates rapidly during an adolescent growth spurt period, which usually comes after 10 years of age, the prediction of the progression of scoliosis by the positive wrist sign appears to be an effective strategy. In any case, close follow-up of the spinal deformity is warranted in patients with Marfan syndrome, especially during the growth period when these risk factors are present to enable us to consider an early intervention.

There are a few limitations to this study. First, there might be some selection bias because not all patients with Marfan syndrome were referred to the Orthopedic Department. Selection bias may also exist regarding the data for the prevalence of dural ectasia, because lumbosacral computed tomography or magnetic resonance images were taken in only about 67% of the enrolled patients. Second, the results of the ophthalmologic examinations were available in only a limited population, and hence were not analyzed in the present study. Third, we only considered the magnitude of scoliosis and did not take into account the type of spinal deformity. Some patients with Marfan syndrome exhibit idiopathic-like scoliosis, while others exhibit "collapsing" spinal deformity accompanied by angular kyphoscoliosis, which actually bothers surgeons. Hence, the next goal is to predict the progression of spinal deformity into the "collapsing" type, although these two conditions cannot always be distinguished clearly.

In conclusion, we succeeded in demonstrating the accurate distribution of the severity of scoliosis and identifying the predictive factors for the progression of scoliosis in patients with Marfan syndrome. The high proportion of severe scoliosis in the studied population indicated that spinal deformity in Marfan syndrome is prone to progression. A multivariate logistic regression analysis revealed that female sex and positive wrist signs were predictive factors for progression of scoliosis in Marfan syndrome.

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