Section 4.4: Spine and Soft Tissue Pathology (Low Back Pain, Tendonitis)

Spine and Soft Tissue Pathology

PANCE High-Yield Focus: Spine and soft tissue disorders are extremely common in outpatient clinics and emergency departments. To excel on the PANCE, you must identify red flags of low back pain that warrant immediate imaging (e.g., cauda equina syndrome), differentiate lumbar disc herniation from spinal stenosis based on clinical signs and relieving factors (flexion vs. extension), diagnose carpal tunnel syndrome using physical maneuvers (Phalen's, Tinel's, Durkan's) and direct nerve conduction studies, and identify classic tendonitis presentations (e.g., De Quervain's tenosynovitis with a positive Finkelstein test).

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Low Back Pain (LBP) and Radiculopathy

Clinical Evaluation and Red Flags

Low back pain is the leading cause of disability worldwide. While the majority of cases are mechanical or musculoskeletal (e.g., lumbar strain) and resolve spontaneously within 4 to 6 weeks, clinicians must screen for serious underlying pathologies. Red Flag Symptoms requiring urgent or emergent diagnostic workup (MRI, blood cultures, or surgical consultation) include:

• Cauda Equina Syndrome: Urinary retention (most sensitive), fecal incontinence, saddle anesthesia (numbness in the perineum/buttocks), and progressive, bilateral lower extremity motor weakness. This is a surgical emergency.
• Infection (Epidural Abscess, Osteomyelitis): Fever, chills, intravenous drug use, history of recent spinal procedures, or persistent localized spinal tenderness.
• Malignancy: Unexplained weight loss, night pain that wakes the patient, history of cancer, or pain unresponsive to rest.

Lumbar Disk Herniation

• Pathophysiology: Occurs when the gelatinous nucleus pulposus herniates through a tear in the outer fibrotic annulus fibrosus, compressing the adjacent nerve root. Most commonly occurs at the L4-L5 or L5-S1 levels.
• Clinical Presentation: Presents with the sudden onset of sharp, shooting, radicular pain radiating down the back of the leg below the knee (sciatica). The pain is characteristically worsened by sitting, coughing, sneezing, or bending forward, as these activities increase intradiscal pressure.
• Physical Exam:
  • Straight Leg Raise (SLR): Passive elevation of the extended leg on the affected side reproduces radicular pain below the knee between 30 and 70 degrees (highly sensitive).
  • Crossed Straight Leg Raise: Raising the asymptomatic leg reproduces radicular pain in the affected leg (highly specific).
  • Neurological Deficits by Level:
    • L4 Nerve Root: Weakness in ankle dorsiflexion (difficulty heel walking), decreased sensation over the medial foot, and an absent/diminished patellar tendon reflex.
    • L5 Nerve Root: Weakness in great toe extension (extensor hallucis longus), and decreased sensation over the dorsum of the foot and first web space. Reflexes are normal.
    • S1 Nerve Root: Weakness in ankle plantarflexion (difficulty toe walking), decreased sensation over the lateral foot and sole, and an absent/diminished Achilles tendon reflex.

Spinal Stenosis

• Pathophysiology: Acquired narrowing of the lumbar spinal canal, compressing the nerve roots of the cauda equina. Typically caused by degenerative changes, including ligamentum flavum hypertrophy, facet joint osteophytes, and bulging discs.
• Clinical Presentation: Presents with neurogenic claudication—bilateral pain, numbness, and heaviness in the buttocks, thighs, or calves.
• Relieving Factors: The pain is characteristically relieved by sitting, lying flat, or bending forward at the waist (e.g., pushing a shopping cart, known as the 'shopping cart sign'). Bending forward flexes the lumbar spine, which increases the spinal canal diameter and relieves nerve compression.
• Worsening Factors: Worsened by prolonged standing or walking, which induces lumbar lordosis (extension), narrowing the canal.
• Diagnostics: MRI is the diagnostic test of choice.

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Carpal Tunnel Syndrome (CTS)

Pathophysiology and Risk Factors

Carpal tunnel syndrome is the most common entrapment neuropathy, resulting from compression of the median nerve as it passes through the carpal tunnel beneath the transverse carpal ligament (flexor retinaculum).

• Risk Factors: Repetitive wrist movements, pregnancy (fluid retention), hypothyroidism, diabetes, and rheumatoid arthritis.

Clinical Presentation

• Sensory Symptoms: Numbness, paresthesias, and burning pain in the median nerve distribution (volar aspect of the thumb, index finger, middle finger, and the radial half of the ring finger). Pain is characteristically worse at night, waking the patient, who may shake their hands for relief ('flick sign').
• Motor Symptoms (Late): Weakness in thumb opposition and abduction, and visible atrophy of the thenar eminence (spares the hypothenar eminence, which is ulnar nerve).

Diagnostic Maneuvers

• Phalen's Maneuver: The patient holds the wrists in complete flexion for 60 seconds. A positive test reproduces paresthesias in the median nerve distribution.
• Tinel's Sign: Light percussion over the median nerve at the volar wrist crease. A positive test produces tingling/shooting pain in the median nerve distribution.
• Durkan's Compression Test: Direct pressure over the carpal tunnel for 30 seconds. This is the most sensitive and specific physical exam maneuver for CTS.
• Confirmation: Electromyography (EMG) and nerve conduction velocity studies.

Management

• Conservative: Wrist splinting in a neutral position (night splints are first-line), NSAIDs, and activity modification.
• Interventional: Corticosteroid injection into the carpal tunnel.
• Surgical: Surgical decompression (releasing the transverse carpal ligament) is indicated for patients with progressive motor weakness, thenar atrophy, or symptoms refractory to conservative management.

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Tendonitis & Bursitis

De Quervain's Tenosynovitis

• Definition: Stenosing tenosynovitis of the first dorsal compartment of the wrist, involving the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons.
• Clinical Presentation: Radial-sided wrist pain that worsens with thumb movement or gripping.
• Diagnostics: Finkelstein Test (the patient places the thumb inside a closed fist, and the clinician passively deviates the wrist ulnarly. Exquisite pain along the radial styloid is positive).
• Management: Thumb spica splint, NSAIDs, and corticosteroid injection.

Epicondylitis

• Lateral Epicondylitis (Tennis Elbow): Inflammation of the extensor carpi radialis brevis (ECRB) tendon. Presents with pain at the lateral epicondyle, worsened by resisted wrist extension and forearm pronation.
• Medial Epicondylitis (Golfer's Elbow): Inflammation of the pronator teres and flexor carpi radialis tendons. Presents with pain at the medial epicondyle, worsened by resisted wrist flexion and forearm supination.

Olecranon Bursitis

Inflammatory or infectious swelling of the olecranon bursa at the elbow. Presents as a fluctuant, 'goose-egg' swelling over the posterior elbow.

• Septic Bursitis: Often caused by direct inoculation of S. aureus. Presents with erythema, warmth, tenderness, and fever.
• Management: Aspiration of the bursa is necessary to rule out infection and gout. Non-septic is treated with compression, ice, and NSAIDs. Septic requires antibiotic therapy and drainage.

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Clinical Comparison: Disc Herniation vs. Spinal Stenosis