Back Problems

9.1 Mechanical Low Back Pain (LBP)

Adv Stud Med 2004;4:135; Prim Care 2004;31:33; Phy Sportsmed 2001;29:38; Nejm 2001;344:363; Jama 1992;268:760; AHCPR Pub No 95-0642 Dec 1994

Cause: Repetitive overuse or single-event injury (MVA, golf swing, fall).

Epidem:

Yearly prevalence of 50% with 15-20% presenting for care.
60-90% lifetime incidence.
Most common cause of disability in <45 y/o age group.
90% recover in 6-12 w.
Estimated annual cost of $38-50b.
97% are mechanical in origin.

Pathophys:

Anatomy:

Bony: 3-joint complex at each level (2 facet joints and disc interposed between 2 vertebrae); degeneration of the disc transfers weight-bearing and rotational load to the facet joints causing joint inflammation and degeneration.
Muscular Anatomy:
- Anterior group-abdominal and psoas muscles.
- Posterior group-erector spinae, profundi, and intersegmental muscles.
ROM: Forward flexion: 90°, extension: 30°, side flexion: 30°, trunk rotation: 70°; these are combined numbers, but most
notable is a reversal of normal lumbar lordosis with forward bend resulting in a smooth kyphotic bowing of the lower back.
Most pain generators in the disc, facet joint capsule, anterior and posterior longitudinal ligaments, muscles and other supporting ligaments.

Sx:

Traumatic injury: fall, MVA, lifting or twisting, repetitive bending.
Mild/mod/severe lumbar pain with minimal radiation.
H/o prolonged sitting with work or travel.
No “red flags.”
- Fracture: h/o trauma.
- Infection or cancer: age > 60, weight loss, fever, night pain, h/o cancer (bone mets common in breast, lung, thyroid, renal, prostate), infection risk factors of iv drug use, immune suppression, recent bacterial infection.
Cauda equina syndrome: saddle anesthesia, bowel or bladder dysfunction, progressive neurologic deficit.

Si: Paraspinal muscle tenderness, no bony tenderness, and pain in back with passive knee-to-chest stretch, limited ability to forward bend; negative discogenic exam (see 9.2).

Crs: Ninety percent of episodes of mechanical LBP will resolve in 12 w.

Cmplc: Prolonged disability for work, recurrent LBP, inability to participate in sport/recreational activity.

Diff Dx: Discogenic back pain (see 9.2), infection, metastatic disease (breast, lung, thyroid, renal cell, prostate), cauda equina syndrome, fracture (acute: spinous process, compression fx; chronic/subacute: stress fx of pars), SI dysfunction (see 9.3); non-back pain (AAA, pyelonephritis, posterior penetrating ulcer, pancreatitis).

Lab: If indicated, consider CBC, ESR, and UA.

X-ray:

Image, if h/o trauma, “red flags,” symptoms >1 month.
Lumbar spine series (AP, LAT, and cone down lateral of L5-S1).
Bone scan for occult injury or infection.
MRI usually not necessary.

Rx: See 22.3 for back rehabilitation exercises.

Initial phase:

Bed rest <48 hr maximum if any.
Ice massage (15 min every 2 hr) followed by passive knee-to-chest stretch (one leg at a time then both legs together).
NSAID of choice for 5-7 d.
Short-term use of narcotic pain meds for severe pain.
Valium 5 mg tid for 1-2 d for severe spasm.
Daily walks followed by stretching
Physical therapy for modalities and stretching.
- Ice massage.
- Electrical stimulation.
- Iontophoresis/phonophoresis.

Second phase:

Continued pain management.
Consider low dose TCA (Elavil 10-50 mg hs or Pamelor 10-50 mg hs) for chronic pain (>12 w) and sleep disturbance.
Survey for “red flags.”
Stretching of hamstrings and back (knee-chest).
Strengthening of back flexors (abs) and extensors.
Injection of trigger points (1 cc of 1% lidocaine at each site).

Prevention:

Aerobic exercise, general conditioning, weight management.
Proper lifting techniques and posture.
Core strengthening.

Referral:

“Red flags” to appropriate consultant asap.
Physical therapy for rehab and lumbar stabilization program.
Pain clinic for chronic pain management.
Chiropractic for manipulative management.
Osteopath for OMT.

Return to Activity: Activity is the cornerstone of therapy (Spine 2002;27:1736); when pt can tolerate flexion/extension activities, has a normal neurologic exam and functional performance of gait, lumbopelvic rhythm on FF, and a desire to return to activity whether it be sport or occupation.

9.2 Discogenic Back Pain

Sciatica or Herniated Nucleus Pulposis (HNP)

Adv Stud Med 2004;4:135; Prim Care 2004;31:33; Am Fam Phys 2000;61:1779; The Low Back Pain Handbook. St. Louis: Mosby 1996:71

Cause: Bending/twisting motion causing herniation of the nucleus pulposis through the annulus fibrosis.

Epidem:

Middle-aged adults 30-40 y/o.
Represents about 4% of all LBP patients (Adv Stud Med 2004; 4:135).
95% at L4-5 and L5-S1.
75% resolve spontaneously within 6 m.
Cumulative risk of 2nd proven disc during next 20 yr is 8%.
Most commonly involve L4-5 or L5-S1 with involvement of the L4, L5, or S1 nerve roots.