What is the best course of action for an adult patient with no known medical history who is experiencing low back pain and left flank pain after a fall?

Immediate Evaluation and Management of Post-Fall Low Back and Flank Pain

Obtain a focused history and physical examination immediately to identify red flags, then proceed with plain radiography of the thoracolumbar spine to evaluate for vertebral compression fracture, given the mechanism of injury and location of pain. 1, 2, 3

Critical Red Flags to Assess Immediately

Your first priority is to rule out serious pathology that requires urgent intervention:

• Cauda equina syndrome - Check for urinary retention, fecal incontinence, saddle anesthesia, and motor deficits at multiple levels, which require immediate MRI and neurosurgical consultation 3, 4
• Vertebral compression fracture - The combination of fall mechanism and midline tenderness makes this highly likely, especially if the patient has osteoporosis risk factors or steroid use 2, 3
• Renal injury - Left flank pain after trauma warrants consideration of kidney injury, though this is less common than musculoskeletal causes 1
• Progressive neurologic deficits - Assess for motor weakness, sensory changes in dermatomal distribution, and asymmetric reflexes 3, 4

Physical Examination Priorities

• Midline tenderness strongly suggests vertebral compression fracture in the setting of trauma, with a positive likelihood ratio of 14.7 in high-risk patients 2, 3
• Straight leg raise test to evaluate for radiculopathy if pain radiates below the knee 3, 5
• Neurological examination including motor strength, sensory testing, and reflexes in lower extremities 1, 4
• Costovertebral angle tenderness to assess for possible renal injury given the flank pain component 1

Imaging Strategy

Plain radiography of the thoracolumbar spine is indicated as the initial imaging study because the patient has a clear trauma mechanism with midline and flank pain, making vertebral compression fracture a significant concern 2, 3. This differs from routine low back pain where imaging is not recommended.

• If plain films are negative but clinical suspicion remains high (persistent pain, significant mechanism), obtain MRI within 2-3 days as occult fractures can be missed on x-ray 6
• The AAOS guidelines demonstrate that initial negative radiographs do not rule out fracture, and MRI may reveal occult basicervical or vertebral fractures 6
• If flank pain is severe or hematuria is present, consider CT abdomen/pelvis to evaluate kidneys 1

Initial Management While Awaiting Imaging

• Advise modified activity - The patient should avoid activities that worsen pain but does not require strict bed rest, as bed rest leads to deconditioning 1, 2, 7
• NSAIDs as first-line medication - These provide superior pain relief compared to acetaminophen for acute traumatic back pain (moderate-quality evidence) 6, 1, 2
• Avoid opioids initially - NSAIDs have fewer adverse effects than opioids and are equally effective for acute low back pain 6, 1
• Ice application to painful areas in the first 48 hours 7

Common Pitfall to Avoid

Do not dismiss this as simple mechanical low back pain and send the patient home without imaging. The trauma mechanism combined with midline tenderness creates a significantly elevated pretest probability for vertebral compression fracture that warrants radiographic evaluation 2, 3. The AAOS case studies specifically highlight that patients with post-fall pain and initially negative plain films may have occult fractures requiring MRI 6.

Follow-Up Plan

• If imaging reveals vertebral compression fracture, refer to orthopedic spine surgery for evaluation and consider osteoporosis workup 6
• If imaging is negative but pain persists or worsens over 2-3 days, obtain MRI to evaluate for occult fracture 6, 2
• Reevaluate within 48-72 hours if symptoms are not improving, or immediately if any neurologic symptoms develop 1, 2
• If pain resolves with conservative management and imaging is negative, transition to standard acute low back pain management with activity as tolerated 1, 7