Although BSCM surgery has significant associated risks, including perioperative complications, new neurological deficits, and death, most patients have favorable outcomes. Overall, surgery markedly improved the risk of rehemorrhage and related symptoms and should be considered in patients with accessible lesions.

Study Design-Correlation of locations of sacral insufficiency fractures are made to regions of stress depicted by finite element analysis derived from biomechanical models of patient activities.Objective-Sacral insufficiency fractures occur at consistent locations. It was postulated that sacral anatomy and sites of stress within the sacrum with routine activities in the setting of osteoporosis are foundations for determining patterns for the majority of sacral insufficiency fractures. Summary of Background Data-The predominant vertical components of sacral insufficiency fractures most frequently occur bilaterally through the alar regions of the sacrum which are the thickest and most robust appearing portions of the sacrum instead of subjacent to the central sacrum which bears the downward force of the spine.Methods-First, the exact locations of 108 cases of sacral insufficiency fractures were catalogued and compared to sacral anatomy. Second, different routine activities were simulated by pelvic models from CT scans of the pelvis and finite element analysis. Analyses were done to correlate sites of stress with activities within the sacrum and pelvis compared to patterns of sacral insufficiency fractures from 108 cases.Results-The sites of stress depicted by the finite element analysis walking model strongly correlated with identical locations for most sacral and pelvic insufficiency fractures. Consistent patterns of sacral insufficiency fractures emerged from the 108 cases and a biomechanical classification system is introduced. Additionally, alteration of walking mechanics and asymmetric sacral stress may alter the pattern of sacral insufficiency fractures noted with hip pathology (p=.002).Conclusions-Locations of sacral insufficiency fractures are nearly congruous with stress depicted by walking biomechanical models. Knowledge of stress locations with activities, cortical bone transmission of stress, usual fracture patterns, intensity of sacral stress with different activities, and modifiers of walking mechanics may aid medical management, interventional, or surgical efforts. NIH Public AccessAuthor Manuscript Spine (Phila Pa 1976). Author manuscript; available in PMC 2009 July 13. Published in final edited form as:Spine (Phila Pa 1976 Key Points• Identify the exact locations of sacral insufficiency fractures from large a consecutive series of cases by MRI and/or CT anatomical imaging methods.• Biomechanical model simulations to determine locations of stress within the sacrum with patient activities determined by finite element analysis.• Match clinical locations of sacral insufficiency fractures and sacral stress with activities as identified by the biomechanical models.• Sacral insufficiency fracture biomechanical classification system is introduced.• Knowledge of sacral stress locations with activities, cortical bone transmission of stress, usual sacral insufficiency fracture patterns, intensity of sacral stress with different activities, and modifiers of walking mechanics may aid medical, interve...

Compared with adults, pediatric patients with BCSMs tend to have larger lesions and higher rates of recurrence (regrowth of residual lesion). Given the greater life expectancy of children, surgical treatment seems warranted in those with surgically accessible lesions that have bled. Outcomes were similar to those in our adult series of patients with BSCMs.