What is the assessment and treatment plan for an 18-year-old patient with no reported history of injury, presenting with back pain in the middle to buttock area, accompanied by an indentation and pain?

Assessment and Treatment Plan for 18-Year-Old with Mid-Back to Buttock Pain and Indentation

Begin with plain radiography (AP and lateral views) of the spine as the initial imaging study, as this remains the standard of care for evaluating back pain in young adults and can identify structural abnormalities, though negative radiographs do not exclude pathology. 1

Immediate Red Flag Assessment

First, systematically exclude emergent conditions through targeted history and examination:

• Cauda equina syndrome: Ask specifically about urinary retention, fecal incontinence, saddle anesthesia (numbness in the "butt" region matching the patient's complaint), and bilateral leg weakness 1, 2
• Malignancy: Although less likely at age 18, assess for unexplained weight loss, night pain, and any history of cancer 1, 2
• Infection: Evaluate for fever, recent infection, IV drug use, or immunocompromised status 2
• Fracture: Consider trauma history (despite patient denial), participation in high-impact sports, or steroid use 2

The "indentation with pain" described by the patient warrants particular attention—this could represent a structural abnormality, sacral dimple, or localized tenderness that needs physical examination correlation.

Physical Examination Priorities

Perform a focused examination to differentiate between common etiologies in this age group:

• Spondylolysis/spondylolisthesis: Palpate for step-off deformity at the lumbosacral junction, assess pain with hyperextension (common in young athletes) 1, 3
• Sacroiliac joint dysfunction: Perform FABER test (flexion, abduction, external rotation), assess for buttock tenderness over SI joints 1, 2
• Piriformis syndrome: Check for buttock pain with FADIR maneuver (flexion, adduction, internal rotation of hip), tenderness in sciatic notch, pain exacerbated by prolonged sitting 4
• Neurologic examination: Test lower extremity strength, sensation in dermatomal distribution, reflexes, and straight leg raise to exclude radiculopathy 1

Imaging Strategy

Obtain plain radiographs (AP and lateral) of the lumbar spine and pelvis as the first-line imaging study. 1 This provides 9-22% diagnostic yield when combined with detailed history and physical examination and can identify:

• Spondylolysis/spondylolisthesis (historically the most common cause in this age group) 1
• Structural abnormalities
• Bony lesions

Do NOT obtain MRI initially unless red flags are present. 1, 2 Early imaging does not improve outcomes and leads to identification of incidental findings that correlate poorly with symptoms. 1, 2

If radiographs are negative but clinical suspicion remains high (particularly given the "indentation" finding), consider:

• MRI without contrast of the lumbar spine and sacrum to evaluate for disc pathology, soft tissue abnormalities, or occult structural lesions 1
• Bone scan with SPECT/CT if spondylolysis is suspected but not visible on plain films 1

Treatment Plan

Immediate Management (First 4-6 Weeks)

Advise the patient to remain active and avoid bed rest—this is more effective than rest for back pain. 1, 2

• NSAIDs: Prescribe the lowest effective dose as first-line pharmacologic treatment 1
• Activity modification: Avoid activities that exacerbate pain (particularly hyperextension if spondylolysis suspected), but maintain general activity 1, 3
• Patient education: Explain that most back pain improves substantially within the first month, and early imaging rarely identifies a precise cause 1

If Symptoms Persist Beyond 4-6 Weeks

• Physical therapy: Refer for structured exercise program focusing on core strengthening and flexibility 1
• Reassess imaging: If not already obtained, consider MRI at this point if patient remains symptomatic and is a potential candidate for interventional treatment 1
• Specialist referral: Consider referral to sports medicine, orthopedics, or physiatry if symptoms persist beyond 6-8 weeks despite conservative management 1

Special Considerations for This Age Group

Young adults, particularly athletes, have unique risk factors:

• Mechanical stress: Assess participation in sports requiring repetitive hyperextension, hyperflexion, or rotation (gymnastics, football, dance) 1, 3
• Growth-related issues: The adolescent spine has different biomechanics and is at increased risk for overuse injuries 3
• Disc pathology: Recent studies show intervertebral disc pathology is increasingly common in young patients due to improved MRI detection 1

Critical Pitfalls to Avoid

• Do not order MRI in the first 4-6 weeks unless red flags are present—this leads to identification of abnormalities (like disc bulges) that are often asymptomatic and correlate poorly with clinical symptoms 1, 2
• Do not dismiss the "indentation" finding—this requires direct visualization and palpation to determine if it represents a structural abnormality, sacral dimple, or area of localized tenderness 1
• Do not assume "no injury" means no structural problem—overuse injuries and stress fractures occur without acute trauma 3

Follow-Up Timeline

• Reassess in 1 month if symptoms persist without improvement 2, 5
• Immediate return if any red flag symptoms develop (bowel/bladder dysfunction, progressive weakness, saddle anesthesia) 1, 2
• Consider advanced imaging at 4-6 weeks if no improvement with conservative management 1