Update on bone fragility in spina bifida

Abstract

BACKGROUND CONTEXT: Patients with spina bifida (SB) are at risk for pathological fractures and low bone mineral density (BMD). PURPOSE AND METHODS: This article reviews the literature and provides a comprehensive overview of how the characteristics of SB and its associated comorbidities intersect with bone fragility to identify possible pathophysiological mechanisms of fractures and low BMD. RESULTS: Bone fragility occurs early in the life of patients with SB as a result of a disturbance that determines changes in bone shape, quantity, and quality, as poor mineralization reduces bone stiffness. Bone fragility in SB occurs due to local and systemic factors and may be considered a state of impaired bone quality of multifactorial aetiology, with complex interacting influences of neurological, metabolic, and endocrinological origins and the presence of smaller bones. Bone fragility should be evaluated globally according to skeletal age and Tanner staging. The phases of the evolution of Charcot joints seem to intercept the evolution of epiphyseal fractures. Charcot arthropathy in SB may be initiated by the occurrence of repetitive trauma and fractures in epiphyseal and subepiphyseal regions, where there is a deficit of bone mineralization and greater bone mass deficits. CONCLUSION: Bone fragility in MMC potentially has a multifactorial neuro-endocrinological-metabolic-renal dimension, with smaller bones, lower bone mass, and mineralization deficits affecting bone strength.

Quantitative Computed Tomography Assessment of Bone Deficits in Ambulatory Children and Adolescents with Spina Bifida: Importance of Puberty

“…Multiple studies using DXA have reported lower BMD in patients with higher lesion levels and lower ambulatory ability. (14)(15)(16)(17)19,21,22) The most striking difference between neurosegmental subgroups observed in our study was lower cancellous density in the metaphyses in the lumbar groups compared with the sacral group. Despite this lower cancellous density, weighted area, a surrogate for total bone mass, was similar among the neurosegmental groups.…”

“…(14)(15)(16)(17)(18)(19)(20)(21) These studies have generally found reduced BMD in persons with SB, particularly in the lower extremities. (22) BMD decreases with higher levels of neurologic involvement and lower ambulatory ability. (14)(15)(16)(17)19,21) Prior fracture and periods of immobilization also reduce BMD.…”

“…(14)(15)(16)(17)19,21) Prior fracture and periods of immobilization also reduce BMD. (22) Although these studies provide insight into bone deficits in SB, they utilize two-dimensional (2D) projection techniques (DXA and SPA) that cannot fully account for the bone's three-dimensional (3D) structure. DXA measurements are influenced by bone and body size and inhomogeneous fat distribution, (23,24) which are particularly problematic for children who are growing and for patient populations with short stature and high body fat as is common in SB.…”

Pediatric Spina Bifida and Spinal Cord Injury

“…Osteoporosis is frequently seen below the level of the lesion and fractures are commonly seen due to smaller bones, lower bone mass, and mineralization deficits associated with endocrinologic and metabolic abnormalities, particularly during critical periods of bone deposition [ 51 , 52 ]. Those with higher SB lesions who are non-ambulatory tend to have decreased activity levels, higher body fat levels, and more contractures, all lending to an increased fracture risk [ 52 ].…”

Osteoporosis in Adult Patients with Intellectual and Developmental Disabilities: Special Considerations for Diagnosis, Prevention, and Management

“…Lennox-Gestaut syndromeSevere childhood seizure syndrome with multiple causes, including genetic mutations, perinatal injuries, cortical malformations, infections, and tumors Unclear whether OP results from the underlying disease, external factors (antiepileptics, immobility, malnutrition), or both14 Spina bifida Congenital disorder caused by incomplete closure of the vertebral column ± meninges during embryogenesis Decreased bone strength resulting from smaller bones, mineralization defects, and lower bone mass15 OP, osteoporosis.Review ArticleSouthern Medical Journal • Volume 114, Number 4, April 2021…”