Back Pain: Part 1

Happy New Year!

So on to the show with back pain today. I actually took a lot of notes on this chapter and am finishing it up today so we'll talk about infectious diarrhea another time.

So back pain is a common outpatient complaint which is why I decided to read about it - not to mention the large amount of money lost each year to back pain. The unfortunate part is that back pain is often difficult to treat and a lot of spinal surgeries don't make the pain go away. I read Jerome Groupman's book "How Doctors Think" a couple months ago and he mentions touches on how spinal fusion surgeries often don't alleviate back pain.

Anyhow, some notes on the chapter:
Cervical nerve roots exit above the corresponding vertebral body, ie C6 exits at the C5-6 space
Thoracic and lumbar nerve roots exit below, ie T1 at the T1-T2 space

Serious underlying disorders to look out for when evaluating back pain are: radiculopathy, fracture, tumor, infection, and referred pain from visceral structures

Pain sensitive structures include periosteum, dura, facet joints, annulus fibrosis, epidural veins, and posterior longitudinal ligament

Types of back pain include:
1) local - secondary to pain-sensitive structures that compress or irritate nerve endings
2) Referred - abdominal and pelvic viscera pain, usually unaffected by posture
3) Spine Origin - back/butt/leg pain, upper lumbar pain leads to pain in the lumbar/groin/ant thigh while lower lumbar pain leads to pain the butt/post thigh/calves/feet. Not a dermatomal distribution but called "sclerotomal"
4) Radicular - sharp or radiating pain which follows a nerve root territory. Worse with coughing, sneezing, vasalva. Sitting stretches the sciatic nerve and can lead to pain when L5 and S1 roots are involved.
5) Muscle spasms

On physical exam:
-Pain of bony spine origin leads to reproducible pain on palpation of the spinous processes
- forward bending may be limited in muscle spasms
- lumbar spine disease - has normal hip flexion but limited lumbar flexion
- lateral bending to the opposite side stretches and irritates the nerve root
- hip pain can be elicited by
(1) Patrick's sign - flexed hip and knee with internal and external rotation
(2) tapping heel with the leg extended
-straight leg raising done with passive hip flexion (and with or without passive dorsifleciton of the foot). Normally a person can go up to eighty degrees. The test is positive if pain is reproduces on the test. Works by stretching the L5 and S1 nerve roots.
-crossed straight leg test - same as above but pain is reproduced on the opposite side. More spec and less sensitive for disc herniation than regular straight leg raise.
-reverse straigh leg raise: pt stands and test passive flexion of leg with knee extension. Stretches the L2-4 nerve roots and femoral nerve. Postive when pt's pain is reproduced.



Tests
- do routine labs for acute back pain less than 3 months - CBC, ESR, UA
- CT better for fracture, good for trauma, but usually unhelpful in acute pain
- MRI and CT myelography usually best choice for serious spine diseases with CT-myelography better for lateral recesses of spine, bony lesions and claustrophobic patients.
-EMG can test the integrity of the peripheral nervous system. Normal in sensory root injury.