Lower Back Pain

Definition
A common musculoskeletal disorder affecting 80% of people at some point in their lives.


Epidemiology

• LBP is one of the most common primary-care complaints.
• Repetitive episodes are common.
• Predominant age: ≥25 years
• M = F

Aetiology

• Normal aging process of musculoskeletal system aggravates an acute event.
• Degenerative joint disease of LS spine
• In primary-care setting, <15% of LBP patients have identifiable underlying disease

Risk Factors

• Age
• Activity (e.g., heavy lifting, bending, twisting)
• Smoking
• Obesity
• Vibration (e.g., driving motor vehicles)
• Sedentary lifestyle
• Psychosocial factors such as increased stress, anxiety, or depressed mood

General Prevention

• Maintaining physical fitness
• Weight loss

Presentation

History	Onset of pain begins either suddenly after injury or gradually over the next 24 h. Occasional radiation of pain to buttocks and/or posterior thighs stopping at knees Pain pattern is referred rather than radicular. Back pain is worse than leg pain. Pain is aggravated by back motion, sitting, standing, lifting, bending, and twisting. Pain is relieved by rest. Bowel and bladder function are preserved. Psychosocial stressors at work and/or home may be present. Medical history and previous injuries should be noted.
Red flags	Age >50 years or <20 years (neoplastic) History of cancer (carcinoma recurrence) Night sweats or weight loss (neoplasm, rheumatologic) Incontinence or saddle anesthesia (nerve compromise/cauda equina syndrome) Recent bacterial infection (infectious) Pain worse when supine (rheumatologic, nerve compromise) History of trauma (fracture)
Physical Exam	Observation reveals preferred posture, facial expressions, and pain behaviors. Normal motor, sensory, and reflex examinations Decreased lumbar range of motion, paraspinous musculature tenderness, and spasm Nerve root stretch tests are often negative. Straight-leg raise (causing spinal motion) may increase LBP, but not leg pain.

Investigations

Lab tests	Not typically indicated on initial presentation For those with red flags, pain that worsens, persists for >6 weeks, and/or is recalcitrant to conservative treatment measures, consider the following: CBC with differential Erythrocyte sedimentation rate (ESR) Alkaline and acid phosphatase Serum calcium Serum protein electrophoresis
Special tests	System-directed investigation
Plain radiographs	Not recommended in the absence of red flag Indicated for persistent symptoms (>6 weeks), age >50 years, systemic symptoms, presence of neurologic deficits or trauma, history of cancer, use of immunosuppressants, IV drug abuse, or if abnormalities such as ankylosing spondylitis are suspected Anteroposterior, lateral, spot lateral of L5–S1, and oblique films are included in routine lumbosacral series.
Bone scan	(scintigraphy) Technetium-99m-labeled phosphorus to rule out fractures, infections, or metastases
MRI and CT	Indicated only for persistent symptoms, neurologic deficits, and/or suspected infection or malignancy: MRI is useful for visualization of soft tissue. CT scan is useful for visualization of bony anatomy.

Differential Diagnosis

Structural	Lumbar strain/sprain Herniated lumbar intervertebral disk Degenerative disk disease Degenerative segmental instability Spinal stenosis Spondylolisthesis Congenital disease: Severe kyphosis, severe scoliosis Fractures
Inflammatory	Ankylosing spondylitis and related inflammatory spondylopathies Infection: Vertebral osteomyelitis Rheumatoid arthritis
Neoplastic	Primary tumors Metastases
Referred pain	Orthopedic: Osteoarthritis of hip Sacroiliac joint disease GI: Duodenal ulcer, chronic pancreatitis, cholecystitis, irritable bowel syndrome, diverticulitis Genitourinary: Pyelonephritis, nephrolithiasis, prostatism Gynecologic: Pregnancy, endometriosis, ovarian cystic disease, pelvic inflammatory disease Cardiovascular: Abdominal aortic aneurysm, vascular claudication

Management

NSAIDs	Agents are considered equally effective (3)[A]: Ibuprofen: 800 mg PO q6h × 10 days, then as needed (maximum 3,200 mg/d) Naproxen: 500 mg PO b.i.d. × 10 days, then as needed (maximum 1,500 mg/d) Adverse reactions: Fluid retention, rash, GI discomfort, dizziness, GI bleeding, acute renal failure or use COX-2 inhibitors
Muscle relaxants	Use with caution (avoid alcohol, no driving or operating heavy machinery); comparative efficacy to NSAIDs is unknown (4)[A]. Cyclobenzaprine (Flexeril): 10 mg PO at bedtime or q8h (maximum 60 mg/d) Carisoprodol (Soma): 350 mg PO t.i.d. and at bedtime Metaxalone (Skelaxin): 800 mg PO t.i.d.–q.i.d. Adverse reactions: Sedation, N/V, dizziness
Opioid analgesic	Short-acting combination opioid analgesic products should be considered only for moderate–severe pain not controlled with NSAIDs and/or muscle relaxants alone. E.g., Vicodin; associated with inducing chronic LBP.
Follow-up	Bed rest is not recommended (5)[A]. Restricted activities for 3–6 weeks. Back-specific exercises should be avoided. Activities of daily living should be resumed as soon as possible (5)[A]. Estimated duration of care is 1–6 weeks. Assess the following at each follow-up visit: Pain, functional status, and medication-related adverse effects. Reevaluate for possible underlying causes if relief does not occur. Patients should be encouraged to maintain normal levels of activity. Consider ongoing physical therapy. Weight reduction, Smoking cessation, stress reduction, avoidance of aggravating tasks (e.g., heavy lifting, bending, twisting, sudden unexpected movements, or any combination of these tasks)

Complications

• Chronic LBP
• Persistent psychosocial impairment

Prognosis

Usually self-limiting; recovery is expected within 6 weeks in 90% of patients (4).
Symptoms can recur in 50–80% of patients within the 1st year.
Adverse psychosocial factors to resolving back pain:

• Pending litigation or compensation
• Prolonged use of habit-forming medications or alcohol
• Poor coping strategies, depressed or hostile patient
• Job dissatisfaction