Epidemiology Low back pain affects 50-80% of the population during their lifetime $100 billion annual cost secondary only to respiratory infections as a reason for visiting a doctor's office Etiology Mechanism muscle strain most common cause of low back pain most common degenerative disorders lumbar spinal stenosis lumbar disc herniation discogenic back pain Risk factors obesity, smoking, gender lifting, vibration, prolonged sitting job dissatisfaction Red flags infection (IV drug use, history of fever and chills) tumor (history of cancer) trauma (history of car accident or fall) cauda equina syndrome (bowel/bladder changes) Outcomes 90% of low back pain resolves within one year Presentation Symptoms axial pain musculogenic login to view 3 more bullets discogenic pain login to view 2 more bullets mechanical pain login to view 4 more bullets sacroiliac symptoms login to view 1 more bullet peripheral / neurogenic radicular pain login to view 2 more bullets referred pain login to view 3 more bullets neurogenic claudication login to view 2 more bullets myelopathy login to view 3 more bullets conus medullaris syndrome cauda equina syndrome login to view 4 more bullets spinal cord injury login to view 2 more bullets Waddell signs evaluation of non-organic back pain symptoms clinically significant if three positive signs are present: superficial and non-anatomic tenderness pain with axial compression or simulated rotation of the spine negative straight-leg raise with patient distraction regional disturbances that do not follow dermatomal patterns overreaction to physical examination Imaging Radiographs indications pain lasting >1 month and not responsive to nonoperative management red flags MRI highly sensitive and specific high rate of abnormal findings in asymptomatic individuals Positive MRI Findings in Asymptomatic Patients Age (y/o) % HNP % Disc Bulge % Degeneration 20-39 21 56 34 40-59 22 50 59 60-79 36 79 93 Differential Neck and arm pain trauma cervical spondylosis metastatic disease / infection cervical radiculopathy cervical myelopathy ankylosing spondylitis Thoracic back and rib pain trauma metastatic disease / infection thoracic disc herniation osteoporotic compression fracture Low back pain muscle strain disc herniation / discogenic pain degenerative spondylolisthesis spinal stenosis lumbar radiculopathy abdominal aortic aneurysm Sacroiliac pain SI infection ankylosing spondylitis Sacral pain coccydynia sacral insufficiency fracture Treatment dictated by the cause of pain