Sciatica

By admin On Feb 28, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Sciatica

Sciatica

Philip R. Neubauer MD

Damien Doute MD

Basics

Description

Sciatica is pain referred down the leg in a distribution of the sciatic nerve, which courses from the lumbosacral plexus L2–S3.
5 different areas of pain may be noted:
- Back: Midline lumbosacral, radicular radiation pattern
- Buttocks: Deep-seated, “crampy” pain
- Posterior or lateral thigh (L5, S1)
- On occasion, both posterior and lateral thigh
- Anterior thigh (high lumbar root L2, L3, L4)

Epidemiology

Incidence

2% of the general population, with lifetime incidence near 40% (1)

Etiology

Most sciatica is from the intervertebral disc (most commonly, L4–L5) and mechanical compression of the lumbosacral nerve roots.

Diagnosis

Signs and Symptoms

Back:
- Most patients have previous back pain, and 50% of those have a history of trauma (1).
- Pain lateralizes to the hip or leg, gradually or suddenly.
- A precipitating event may occur, such as bending over or straining.
Leg:
- Pain can be more debilitating than back pain.
- L5–S1 root compression: Cramp or a viselike feeling in the gastrocnemius or peroneal muscle belly
- L4: Medial shin or lateral thigh
- L5: Lateral calf
- S1: Back of calf
- L1: Groin
- L2: Medial thigh
- L3: Anterior thigh
- Most adults have pain below the knee.
Foot:
- The most common symptom is paresthesia.
- L5: Foot dorsum
- S1: Lateral foot
- Actual foot pain is unusual.
Rarely, motor symptoms predominate; if they do, consider spinal tumor or peripheral neuropathy.
Aggravating or relieving factors:
- Bending, stooping, lifting, coughing, sneezing, straining, and sitting worsen pain.
- Standing, walking, and resting are more tolerable.
- Lying with the knee or hip flexed and sleeping with a pillow under the knees give some relief.

Physical Exam

Spine:
- Variable examination: Most physical findings are in the legs, not the back.
- Lumbar spine flattened and flexed
- Limited spine extension, forward flexion, and lateral flexion toward affected side
- “Sciatic scoliosis”: Patient leans away from side of pain
Extremities:
- Test all muscle groups and make a chart to document baseline:
  - Flexion/extension/adduction/abduction for the hip
  - Flexion/extension of the knee
  - Dorsiflexion/plantarflexion/eversion/inversion/ flexion of the ankle
  - Flexion/extension of the 1st toe
- Test sensation with pinprick in all dermatomes and compare with those in the contralateral limb.
- Test reflexes
- Trendelenburg sign: A lurch or pelvic
  tilt is noted with ambulation, as is weakness of the hip adductors
  (gluteus medius and minimus).
- Root tension sign: A limited straight-leg
  raise (with a small amount of hip internal rotation and adduction,
  slowly raise leg) reproduces leg pain at <60° of flexion (Fig. 1).
- Contralateral straight-leg raise: When
  the unaffected leg is lifted, the opposite symptomatic side has a
  painful axilla or midline disc.
- Lasègue sign: Pain is increased on forced
  dorsiflexion of the ankle with straight-leg raising and is relieved
  with hip or knee flexion (Fig. 2).
- Bowstring sign:
  - Perform straight-leg raise to the point of sciatica.
  - Allow the knee to flex.
  - Apply pressure to the hamstring insertion at the knee, which stretches the nerve to reproduce leg pain.
- Femoral nerve stretch test: Unilateral thigh pain is produced by knee flexion, tension on the 2nd to the 4th roots.
The diagnosis also is suggested by motor weakness or by sensory or reflex changes.

Fig. 1. The straight-leg-raise test is used to detect nerve root stretch. The knee is kept straight while the hip is flexed.
Muscle wasting:
- Rare unless the lesion is present for >3 weeks
- Marked wasting suggests a tumor.

Tests

Lab

In patients >50 years old, one should exclude the
diagnosis of multiple myeloma with a complete blood count, ESR, and
serum protein electrophoresis.

Imaging

Conventional radiography:
- AP view of the lumbosacral spine
- AP view of the pelvis
Screening radiography:
- Compression fractures (lateral view)
- Spondylolisthesis (lateral view)
- Pedicle destruction in metastatic bone disease (AP view)
- Scoliosis (AP view)
- Tumors of the pelvis (AP view of the pelvis)
MRI is procedure of choice for detecting and defining anatomy of:
- Herniated discs
- Compression from vertebral body fractures
- Marrow involvement from neoplastic processes, spinal cord tumors
CT is effective and used primarily for patients:
- Who cannot undergo MRI
- With previous surgery who have metal implants

Pathological Findings

Nuclear pulposus extruded through a weakened annular fibrosis

Differential Diagnosis

Diabetic neuropathy
Disc space infection or epidural abscess
Spondylogenic: Disc rupture, spinal stenosis, muscle sprain
Psychogenic: Vague and stocking–glove type pain
Neurogenic: Spinal cord tumor or cysts

Fig. 2. The Lasègue maneuver confirms nerve tension, with increased pain as the ankle is dorsiflexed.

P.371

Treatment

General Measures

A systematic approach is necessary to identify the correct diagnosis and minimize disability.
Noninvasive treatment:
- Highly successful
- Patient education:
  - Limit bending, heavy lifting
  - Teach and encourage back strengthening and cardiovascular fitness.
- Limited bed rest (1–3 days), then gradual increase in activity
Invasive treatment:
- Epidural steroids may provide relief of variable duration.

Special Therapy

Physical Therapy

Physical therapy can be useful for back exercises, healthy-back educational programs, and aerobic conditioning.

Medication

First Line

Muscle relaxants
NSAIDs
Avoid narcotics.

Surgery

If nonoperative treatment fails after 6 weeks
If neurologic deficit, cauda equina
Microdiscectomy
Current standard is laminotomy and discectomy.
Minimally invasive microdiscectomy is performed with greater frequency through various tubular and expandable retractor systems.
- The procedure may result in less tissue damage than current procedures.
- Prospective studies comparing this technique to conventional microdiscectomy are underway.

Follow-up

Prognosis

Good; most patients recover spontaneously with some reports of a >70% rate of recovery with nonoperative treatment (2,3).

Complications

Cauda equina syndrome: Large central disc herniation causing bowel/bladder symptoms and findings
Persistent pain
Progressive spondylosis (disc degeneration)

Patient Monitoring

The patient should be seen at 2–4-week intervals to document strength and recovery.

References

1. Frymoyer JW. Back pain and sciatica. N Engl J Med 1988;318:291–300.

2. Awad JN, Moskovich R. Lumbar disc herniations: surgical versus nonsurgical treatment. Clin Orthop Relat Res 2006;443:183–197.

3. Weber H. The natural history of disc herniation and the influence of intervention. Spine 1994;19: 2234–2238.

Additional Reading

McCulloch J, Transfeldt E. Disc degeneration with root irritation: disc ruptures. In: MacNab’s Backache, 3rd ed. Baltimore: Williams & Wilkins, 1997:500–568.

Miscellaneous

Codes

ICD9-CM

722.10 Displacement of herniated disc

Patient Teaching

Patients are instructed on care of the back, to minimize disability.

FAQ

Q: What are the symptoms of sciatica?

A:
Sciatica is a symptom itself. The patient may experience burning, pain,
or a tingling sensation in the back and legs as a result of pressure on
the sciatic nerve.

Q: What are the main causes of sciatica?

A: The most common cause of sciatica is a herniated intervertebral disc.

Q: What are the treatment options for patients with sciatica?

A:
Physical therapy, exercise, and anti- inflammatory medications should
be tried 1st, followed by spinal injections and surgery.