Low Back Pain Prevalence Discussion.

The student should be able to:

Discuss the differential diagnosis for low back pain. Develop physical exam skills in evaluating low back pain. Develop the skills in diagnosis and treatment of low back pain. Recognize red flags for possible serious causes of low back pain. List the indications for imaging studies for low back pain. Propose appropriate treatment for back pain. Discuss the management of refractory back pain with consultation and surgical intervention.

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Knowledge

Low Back Pain Prevalence, Cost, & Duration

Low back pain (LBP) is the fifth most common reason for all doctor visits. In the U.S., lifetime prevalence of LBP is 60% to 80%. The direct and indirect costs for treatment of LBP are estimated to be $100 billion annually. Fortunately, most LBP resolves in two to four weeks.

Common Causes of Back Pain

Musculoskeletal (MSK) and Non-MSK Causes of Back Pain

MSK Causes

Axial: Degenerative disc disease Facet arthritis Sacroiliitis Ankylosing spondylitis Discitis Paraspinal muscular issues SI dysfunction

Radicular: Disc prolapse Spinal stenosis

Trauma: Lumbar strain Compression fracture

Non-MSK Causes

Neoplastic: Lymphoma/leukemia Metastatic disease Multiple myeloma Osteosarcoma

Inflammatory: Rheumatoid Arthritis

Visceral: Endometriosis Prostatitis Renal lithiasis

Infection: Discitis

Herpes zoster Osteomyelitis Pyelonephritis Spinal or epidural abscess

Vascular: Aortic aneurysm

Endocrine: Hyperparathyroidism Osteomalacia Osteoporotic vertebral fracture Paget disease

Gastrointestinal: Pancreatitis Peptic ulcer disease Cholecystitis

Gynecological: Endometriosis Pelvic inflammatory disease

Most Common Causes of Back Pain

There are three major categories of back pain: mechanical, visceral, and non-mechanical. Mechanical

97% of back pain no primary inflammatory or neoplastic cause

Visceral

2% of back pain no primary involvement of the spine, usually from internal organs

Non-mechanical

1% of back pain other

The three most common causes of back pain are all mechanical: 1. lumbar strain/sprain – 70% 2. age-related degenerative joint changes in the discs and facets – 10%. 3. herniated disc – 4% Acute sciatica is lower back pain with radiculopathy below the knee and symptoms lasting up to six weeks. Sciatica is a common and costly problem, caused by a variety of conditions: disc herniation, lumbar spinal stenosis, facet joint osteoarthritis or other arthropathies, spinal cord infection or tumor, or spondylolisthesis. Less common causes of mechanical back pain:

osteoporotic fracture – 4% spinal stenosis – 3%

Uncommon causes of back pain: Pyelonephritis, a visceral cause, accounts for 0.4% of back pain.

Risk Factors for Low Back Pain

Prolonged sitting, with truck driving having the highest rate of LBP, followed by desk jobs Deconditioning Sub-optimal lifting and carrying habits Repetitive bending and lifting Spondylolysis, disc-space narrowing, spinal instability, and spina bifida occulta Obesity Prolonged use of steroids Intravenous drug use Education status: low education is associated with prolonged illness Psycho-social factors: anxiety, depression, stressors in life Occupation: Job dissatisfaction, increased manual demands, and compensation claims

Red Flags For Serious Illness or Neurologic Impairment with Back Pain

Fever Unexplained weight loss Pain at night Bowel or bladder incontinence Urinary retention Neurologic symptoms Saddle anesthesia Trauma

Anatomy of Mechanical Lower Back Pain

Mechanical lower back pain generally involves one or more of the following: 1. bones of the spine 2. muscles and ligaments surrounding the spine 3. nerves (the nerves entering and exiting the spinal cord or problems with the cord itself)

Symptoms of Disc Herniation

When disc herniation is suspected, a very important historical point is the position of comfort or worsening of symptoms. Classically, disc herniation is associated with exacerbation when sitting or bending; and relief while lying or standing. Other symptoms of disc herniation include:

increased pain with coughing and sneezing pain radiating down the leg and sometimes the foot paresthesias muscle weakness, such as foot drop

Red Flags for Serious Underlying Causes of Back Pain

While the majority of back pain has a benign course and resolves within a month, a small number of cases are associated with serious underlying pathology. Timely treatment of these conditions is important to avoid serious consequences. Indications for early diagnostic testing such as x-rays and other imaging and referral are patients with progressive neurological deficits, patients not responding to conservative treatment, and patients with red flags signaling serious medical conditions such as fracture, cancer, infection, and cauda equina syndrome. Knowing this would also help guide the evaluation and treatment of the back pain. While the worst pain a patient has ever had is concerning and needs to be addressed, it is not by itself indicative of a more serious condition. Numbness can be part of cauda equina, but is also common with a simple disc herniation, therefore by itself it is not a red flag. Red Flags by Serious Condition

Cancer

1. History of cancer 2. Unexplained weight loss >10 kg within 6 months 3. Age over 50 years or under 17 years old 4. Failure to improve with therapy 5. Pain persists for more than 4 to 6 weeks 6. Night pain or pain at rest

Infection

1. Persistent fever (temperature over 100.4 F) 2. History of intravenous drug abuse 3. Recent bacterial infection, particularly bacteremia (UTI, cellulitis, pneumonia, pelvic inflammatory disease) 4. Immunocompromised states (chronic steroid use, diabetes, HIV, taking chemotherapeutic or biologic medications)

Cauda Equina Syndrome

1. Urinary incontinence or retention 2. Saddle anesthesia 3. Anal sphincter tone decreased or fecal incontinence 4. Bilateral lower extremity weakness or numbness 5. Progressive neurologic deficits

Significant Herniated Nucleus Pulposus

1. Major muscle weakness (strength 3 of 5 or less) 2. Foot drop

Vertebral Fracture

1. Prolonged use of corticosteroids 2. Mild trauma over age 50 years 3. Age greater than 70 years 4. History of osteoporosis

5. Recent significant trauma at any age (car accident, fall from substantial height) 6. Previous vertebral fracture

Acute Low Back Pain Prognosis

Most cases of low back pain are acute in onset and resolution, with 90% resolving within one month and only 5% remain disabled longer than three months. For patients who are out of work greater than six months, there is only 50% chance of them returning to work; this drops to almost zero chance if greater than two years. Patients who are older (>45) and patients who have psychosocial stress take longer to recover. Recurrence rate for back pain is high at 35 to 75%.

Clinical Skills

Recommended Low Back Pain History

1. History of present illness.

What is the location of the pain? Is it upper, middle or lower back? Left or right side? What is the duration of the pain or how long ago did it start? Is it getting worse or better? Does the pain radiate? Pain that radiates below the knee- more consistent with sciatica; pain around the buttock- more consistent with lumbar strain. What is the severity of the pain? Use a pain scale of 1 to 10 to make the severity somewhat more objective. Intensity of the pain. What is the quality of the pain? Is it achy, or sharp, or dull, or throbbing? Is the pain constant or intermittent? If intermittent, how often does it occur? Is it present at night or at rest? Are there associated symptoms (such as fever, weight loss, weakness, numbness, tingling)? Are there aggravating or alleviating factors? Aggravating circumstances (active vs. passive motion, day vs. night). Valsalva can increase pain from a herniated disk. Alleviating circumstances (medication, positioning-sitting, lying, standing). What has the patient tried to relieve the problem (what worked, what didn’t). Any history of similar problems?

2. Pertinent past history. Recent illnesses, history of recent trauma or injury, patient’s occupation, previous history of back injury, history of back surgery, cancer, or DM. (Fatigue is a nonspecific finding which may not help you to narrow your differential diagnosis.) 3. Review of systems. In order to narrow your differential diagnosis for the patient’s problem, a review of systems, focused on pertinent positives and negatives is important.

Neurologic symptoms: saddle anesthesia, lower extremity numbness, tingling, muscle weakness particularly in the lower extremities, fecal incontinence Urinary symptoms: urinary incontinence, urinary retention, hesitancy, frequency, dysuria Gastrointestinal symptoms: nausea, vomiting, hematemesis, hematochezia, constipation, diarrhea, acid reflux symptoms Constitutional symptoms: fever, unexplained weight loss

4. Current medications and allergies

Approach to the Physical Exam for Back Pain

Perform the back exam systematically in sequential order with the patient: 1. Standing 2. Sitting 3. Supine

Physical Exam for Back Pain – Standing

Throughout the whole exam make certain to note how your patient is sitting, standing, and walking in general, asking yourself, “What is his degree of impairment?” and “How uncomfortable is he?” I. Inspection: Look at posture, contour and symmetry. Also inspect overlying skin to check for any lesions or abnormalities.

Check for lordosis Check for kyphosis Check for scoliosis

Slight scoliosis may be more easily visualized during lumbar flexion. This is performed by having the patient stand with their feet and hands together, like they are about to dive off a diving board, bending forward toward their toes. Look out across the back to see if the shoulders are level. II. Palpation: Check for any tenderness, tightness, rope-like tension, or inflammation in the paraspinous muscles or tenderness

Low Back Pain Prevalence Discussion.

over bony prominences. This procedure checks for muscle spasm, vertebral fracture, or infection. III. Range of Motion (ROM):

Lumbar Flexion (normal is 90 degrees): This is the best measure of spine mobility. Restriction and pain during flexion are suggestive of herniation, osteoarthritis, or muscle spasm. Lumbar Extension (normal is 15 degrees): Pain with extension is suggestive of degenerative disease or spinal stenosis. Lateral motion (normal is 45 degrees): Most patients should be able to touch the proximal fibular head of the knee. Pain on the same side as bending is suggestive of bone pathology, such as osteoarthritis or neural compression. Pain on the opposite side of bending is suggestive of a muscle strain. Range of motion may be varied due to the patient’s age and body habitus

IV. Gait: Ask the patient to walk on heels and toes. Expect normal gait, even with disc herniation. Difficulty with heel walk is associated with L5 disc herniation Difficulty with toe walk is associated with S1 disc herniation

V. Stoop Test: Have the patient go from a standing to squatting position. In patients with central spinal stenosis, squatting will reduce the pain. However, asking the patient to run is not part of a back exam and may cause discomfort to the patient who is already in pain.

Physical Exam for Back Pain – Seated Position

Overview of the Neurologic Exam

Deep Tendon Reflexes

Grading Reflexes: 0 No evidence of contraction 1+ Decreased, but still present (hyporeflexic) 2+ Normal 3+ Increased (hyper-reflexic) 4+ Clonus: Repetitive shortening of the muscle after a single stimulation Decreased patella reflex implies nerve impingement at the L3-L4 level. Decreased Achilles reflex implies nerve impingement of S1 levels. Hyper-reflexia is a sign of upper-motor neuron syndrome associated with spinal cord compression. Muscle Strength

Rating Scale: 0/5 No movement 1/5 Barest flicker of movement of the muscle, though not enough to move the structure to which it’s attached. 2/5 Voluntary movement, which is not sufficient to overcome the force of gravity. For example, the patient would be able to slide their hand across a table but not lift it from the surface. 3/5 Voluntary movement capable of overcoming gravity, but not any applied resistance. For example, the patient could raise their hand off a table, but not if any additional resistance were applied. 4/5 Voluntary movement capable of overcoming “some” resistance 5/5 Normal strength i. Hip Flexion (L 2, 3, 4): Ask the patient to lift his thigh while you push down on his thigh ii. Hip Abduction (L 4, 5, S1): Ask the patient to push his legs apart while you push them together iii. Hip Adduction (L 2, 3, 4): Ask the patient to push his legs together while you push them apart iv. Knee Extension (L 2, 3, 4): Ask the patient to extend their knee while you push it down. v. Knee Flexion (L 5, S1, S2): Ask the patient to flex his knee while you push against it. vi. Ankle Dorsiflexion (L 4, 5): Ask the patient to point his foot up while you push it down. vii. Ankle Plantar Flexion (S 1, S 2): Ask the patient to point his foot down while you push it up. Decreased strength implies nerve impingement of the associated nerve in parenthesis. Sensation Low Back Pain Prevalence Discussion.

Test for sharp and light touch along dermatomal distribution, great toe (L5), lateral malleolus, and posteriolateral foot (S1) Nerve Root Impingement Syndromes

Nerve Root Reflex Pin-Prick Sensation

Motor Examination Functional Test

Low Back Pain Prevalence Discussion.

L3 Patellar tendon reflex Lateral thigh and medial femoral condyle Extend quadriceps Squat down and rise

L4 Patellar tendonreflex Medial leg and medial ankle Dorsiflex ankle Walk on heels

L5 Medial hamstring Lateral leg and dorsum of foot Dorsiflex great toe Walk on heels

S1 Achilles tendonreflex Posterior calf, Sole of foot, and lateral ankle Stand on toes

Walk on toes (plantarflex ankle)

Check for costovertebral angle (CVA) tenderness , a sign suggesting pyelonephritis. Modified version of the straight leg raise (SLR) test

While continuing to talk to the patient, raise each leg by extending the knee from 90 degrees to straight. If the pain is due to structural disease, the patient will instinctively exhibit the “tripod sign” by leaning backward and supporting himself with his outstretched arms on the exam table. (The unmodified version of the straight leg raise (SLR) test is done in the next section of the exam with the patient supine.) Neurological exam

Check reflexes, muscle strength, and sensation of the lower extremities. Focus on the L4, L5, and S1 nerve roots because most neuropathic back pain is due to impingement of these. Therefore, check the patellar reflex (L2-4) and Achilles reflex (S1). Check muscle strength for hip flexion, abduction, and adduction; knee extension and flexion; as well as ankle dorsiflexion and plantar flexion. Also, test for sharp and light touch along the dermatomal distribution of the great toe (L5), lateral malleolus and posterolateral foot (S1). Low Back Pain Prevalence Discussion.

Physical Exam for Back Pain – Supine

I. Abdominal Exam

Auscultation: Check for abdominal bruit, looking for abdominal aortic aneurysm. Palpation: Check for abdominal tenderness (on all patients, not just female patients), pelvic tenderness (pelvic inflammatory disease), pulsatile mass, unequal femoral/brachial pulses (abdominal aortic aneurysm), or any general tenderness indicating visceral pathology. Low Back Pain Prevalence Discussion.