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...

The authors blindly reviewed the charts of 20 patients with normal-pressure hydrocephalus (a disease of unknown cause characterized radiologically as chronic communicating hydrocephalus and clinically by gait apraxia, dementia, and incontinence) who had undergone creation of a ventriculoperitoneal shunt. The initial clinical response to surgery was graded excellent, good, fair, or poor; 5-year follow-up was available in 55% of cases. The magnetic resonance (MR) images obtained in these patients were also blindly reviewed for the magnitude of cerebrospinal fluid (CSF) flow void (graded on the basis of extent rather than degree of signal loss) in the cerebral aqueduct. A significant (P less than .003) correlation existed between good or excellent response to surgery and an increased CSF flow void. The presence of associated deep white matter infarction on MR images did not correlate with a poor response to surgery. On the basis of these findings, it is suggested that patients who fulfill the clinical criteria of NPH and have an increased CSF flow void undergo creation of a shunt.

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Objective To assess the outcomes and safety after CTguided percutaneous sacroplasty in patients with painful sacral insufficiency fractures or pathologic sacral lesions. Methods A retrospective multicenter analysis of consecutive patients undergoing CT-guided sacroplasty for painful sacral insufficiency fractures or sacral lesions was undertaken. The inclusion criteria consisted of severe sacral pain not responding to conservative medical management with imaging evidence of unilateral or bilateral sacral insufficiency fractures or lesions. Outcome measures included hospitalization status (inpatient or outpatient), pre-treatment and posttreatment visual analog scale (VAS) scores, analgesic use and complications. Patients were followed at approximately 1 month and for at least 1 year after their sacroplasty procedure. Results Two hundred and forty-three patients were included in the study, 204 with painful sacral insufficiency fractures and 39 with symptomatic sacral lesions. The average pre-treatment VAS score of 9.261.1 was significantly improved after sacroplasty to 1.961.7 in patients with sacral insufficiency fractures (p<0.001). The average pre-treatment VAS score of 9.060.9 in patients with sacral lesions was significantly improved after sacroplasty to 2.662.4 (p<0.001). There were no major complications or procedure-related deaths. One patient who was treated for a sacral insufficiency fracture experienced radicular pain due to local extravasation of cement that subsequently required surgical decompression for symptomatic relief. Conclusions CT-guided percutaneous sacroplasty is a safe and effective procedure in the treatment of painful sacral insufficiency fractures or lesions. It is associated with prompt and durable pain relief and should be considered as an effective treatment option in this patient population.