What are the initial steps in evaluating and managing a patient with mid back pain after a motor vehicle accident (MVA)?

Differential Diagnoses for Mid Back Pain After Motor Vehicle Accident

After a motor vehicle accident, mid back pain most commonly arises from musculoligamentous injury, but you must systematically rule out serious structural pathology including vertebral fracture, disc injury, facet joint injury, and sacroiliac joint pathology before attributing symptoms to nonspecific causes.

Immediate Red Flag Assessment

Your first priority is identifying conditions requiring urgent intervention 1, 2:

• Cauda equina syndrome: Assess for urinary retention (90% sensitivity), fecal incontinence, bilateral leg weakness, or saddle anesthesia 2, 3
• Vertebral fracture: Look for midline tenderness, especially in patients with osteoporosis, steroid use, or age >65 years 1, 2
• Spinal cord compression: Evaluate for progressive neurologic deficits, severe weakness, or ascending sensory loss 1
• Vascular injury: Consider if high-energy mechanism, altered mental status, or focal neurologic deficits inconsistent with imaging 1

Specific Structural Differentials

Based on diagnostic injection studies, the structural sources of chronic low back pain after MVA have been definitively identified 4:

• Discogenic pain (56% of MVA-related chronic LBP): Presents with axial pain worsened by sitting, forward flexion, and Valsalva maneuvers 4
• Sacroiliac joint pain (26%): Characterized by unilateral buttock pain, pain with prolonged standing, and positive provocative maneuvers 4
• Facet joint pain (19%): Presents with paraspinal tenderness, pain with extension and rotation, and referred pain patterns 4
• Musculoligamentous injury: Most common in acute phase, documented in both animal and human studies of whiplash mechanisms 5

Clinical Context Specific to MVA

Motor vehicle collisions create unique injury patterns you must consider 6, 5:

• 70% of LBP claims involve rear-end collisions, with 40% occurring at low velocities (10-12 km/h) 6
• Interscapular and thoracolumbar pain are frequent complaints extending beyond isolated neck injury 5
• Pre-existing disc degeneration is the most common predisposing condition found in MVA-related LBP cases 6
• Women report persistent pain more commonly (70:30 ratio) 5

Risk Stratification for Imaging

Do not routinely image patients without red flags, even with midline tenderness 1, 2. However, obtain immediate MRI or CT if 1, 2:

• Severe or progressive neurologic deficits are present
• Age >65 years with significant trauma mechanism
• History of cancer, unexplained weight loss, or fever
• Suspected cauda equina syndrome
• High-risk mechanism: falls from >3 feet, high-speed collision, rollover, or ejection 1

For patients without red flags, plain radiography may be reasonable if 1, 2:

• Risk factors for compression fracture (osteoporosis, steroid use, age >65)
• Symptoms persist beyond 4-6 weeks despite conservative management

Additional Differentials to Consider

• Thoracic outlet syndrome: Can cause paresthesias in upper extremities, often from trigger points 5
• Myofascial pain with trigger points: Documented cause of persistent symptoms, responsive to injection therapy 5
• Rib fractures or costochondral injury: Particularly in direct impact or seatbelt injuries
• Visceral injury: Rare but consider with appropriate mechanism (kidney, spleen, pancreas)
• Referred pain from cervical spine: Interscapular pain commonly originates from cervical pathology 5

Critical Pitfalls to Avoid

Be aware that self-reported history may be unreliable in MVA patients 7:

• In 68% of audited cases, patients denied comorbid conditions (previous axial pain, substance abuse, psychological diagnoses) that were documented in prior records 7
• This effect is most pronounced in patients perceiving the accident as another's fault or pursuing compensation claims (80% had undisclosed significant history) 7
• Independently verify previous medical history when possible rather than relying solely on patient report 7

Understand the true causal relationship 8:

• MVA exposure increases risk of future LBP with a relative risk of 2.7 (95% CI 1.9-3.8) 8
• This translates to 63% attributable risk—meaning for patients with chronic LBP after MVA, the collision caused the condition 63% of the time 8
• At 1 year post-crash, at least 31% of exposed individuals report persistent LBP 8

Psychosocial Factors Predicting Poor Outcomes

Assess early for factors associated with chronic disability 1, 5:

• Depression or anxiety
• Job dissatisfaction or disputed compensation claims
• Passive coping strategies
• Multiple symptoms at presentation (paresthesias, interscapular pain, occipital headache)
• Reduced cervical range of motion
• Upper-middle occupational category

Note that litigation does not cure symptoms—most patients are not improved by verdict, contrary to common assumptions 5.