summary Sacral insufficiency fractures are fragility fractures of the sacral spine that occur more commonly in elderly women with osteoporosis Diagnosis can be made with inlet and outlet radiographs of the pelvis. CT or MRI may be helpful for fracture characterization and operative planning Treatment is usually observation and pain control. Surgical management is indicated for patients with progressive pain and/or difficulty ambulating who fail nonoperative treatment Epidemiology Incidence 1% of women >55 y/o increases with age estimated to increase by 23% each year Demographics 2:1 female:male ratio average age 69 y/o Risk factors osteoporosis vitamin D deficiency rheumatoid arthritis prolonged immobilization long-term steroid use pelvic radiation Etiology Pathophysiology mechanism of injury low-energy trauma (i.e. ground-level fall) Associated conditions other fragility fractures (i.e. distal radius, vertebral, or hip fractures) Anatomy Osteology formed by fusion of 5 sacral vertebrae articulates with 5th lumbar vertebra proximally coccyx distally ilium laterally at the sacroiliac joints contains 4 foramina that transmit sacral nerves Nerves L5 nerve root runs on top of the sacral ala S1-4 nerve roots pass through the sacral foramina S1 and S2 nerve roots have a higher rate of injury lower sacral nerve roots (S2-5) function login to view 3 more bullets unilateral preservation of nerves is adequate for bowel and bladder control Biomechanics transmission of load from the first sacral segment through the iliac wings to the acetabulum Classification Denis Classification Zone 1 Fracture lateral to the foramina Zone 2 Fracture through the foramina Zone 3 Fracture medial to the foramina extending into the spinal canal Presentation History low-energy trauma (i.e. ground level fall) Symptoms pain groin, low-back, or buttock pain worse with weight bearing Physical exam limited hip motion neurologic deficits are rare Imaging Radiographs recommended views AP lateral inlet view login to view 1 more bullet outlet view login to view 1 more bullet CT indications negative radiographs but high suspicion for fracture confirmed fracture on radiographs MRI indications negative radiographs and CT but high suspicion for occult fracture Bone scan indications no longer used findings Honda or H sign login to view 1 more bullet Studies Serum labs evaluate for causes of osteoporosis Treatment Nonoperative observation, mobilization, analgesia, osteoporosis screening, and treatment indications login to view 1 more bullet Operative sacroplasty indications login to view 1 more bullet ORIF indications login to view 2 more bullets Techniques Sacroplasty technique injection of polymethylmethacrylate cement complications specific to this treatment cement extrusion login to view 1 more bullet ORIF technique unilateral iliosacral screws login to view 5 more bullets trans-sacral screw login to view 1 more bullet posterior bridging plate login to view 2 more bullets complications specific to this treatment implant loosening hardware failure Complications Nonunion Persistent pain