Lumbar Disk Herniation

Key Features

Essentials of Diagnosis

• Pain with back flexion or prolonged sitting

• Radicular pain into the leg due to compression of neural structures

• Lower extremity numbness and weakness

General Considerations

• Usually due to bending or heavy loading (eg, lifting) with the back in flexion, causing herniation or extrusion of disk contents (nucleus pulposus) into the spinal cord area

• However, there may not be an inciting incident

• Disk herniations usually occur from degenerative disk disease (dessication of the annulus fibrosis) in patients between 30 and 50 years old

• The L5–S1 disk is affected in 90% of cases

• Compression of neural structures, such as the sciatic nerve, causes radicular pain

• Severe compression of the spinal cord can cause the cauda equina syndrome, a surgical emergency

Clinical Findings

• Discogenic pain typically is localized in the low back at the level of the affected disk and is worse with activity

• "Sciatica" causes electric shock-like pain radiating down the posterior aspect of the leg often to below the knee

• Symptoms usually worsen with back flexion such as bending or sitting for long periods (eg, driving)

• A significant disk herniation can cause numbness and weakness, including weakness of plantar flexion of the foot (L5/S1) or dorsiflexion of the toes (L4/L5)

• The cauda equina syndrome should be ruled out if the patient complains of perianal numbness or bowel or bladder incontinence

Diagnosis

• Plain radiographs are helpful to assess

  • Spinal alignment (scoliosis, lordosis)

  • Disk space narrowing

  • Osteoarthritic changes

• MRI

  • Best method to assess the level and morphology of the herniation

  • Recommended if surgery is planned

• Provocative lumbar discography can be helpful for identifying the disk as the source of low back pain

Treatment

Conservative measures

• Bed rest is appropriate for up to 48 hours for acute exacerbation of pain symptoms

• Otherwise, first-line treatments include

  • Modified activities

  • NSAIDs and other analgesics

  • Physical therapy, including core stabilization and McKenzie back exercises (https://sportsrehab.ucsf.edu/sites/sportsrehab.ucsf.edu/files/Mckenzie%20Back%20Protocol.pdf)

Medications

• Oral prednisone

  • Caused a modest improvement in function at 3 weeks but there was no significant improvement in pain in patients with acute radiculopathy who were monitored for 1 year in a randomized trial

  • Initial dose: approximately 1 mg/kg once daily with tapering doses over 10–15 days

• Analgesics for neuropathic pain may be helpful, such as

  • Calcium channel alpha-2-delta ligands (ie, gabapentin, pregabalin)

  • Tricyclic antidepressants

Surgery

• The severity of pain and disability as well as failure of conservative therapy are the most important reasons for surgery

• Microdiskectomy

  • Standard method of treatment

  • Low rate of complications

  • Satisfactory results in over 90% in the largest series

• Minimally invasive percutaneous ...