Correlating Clinical and MRI Scan Findings in Low Back Pain Jim Messerly D.O.

Classification of low back pain Mechanical/Axial-majority of pain is localized to the lumbosacral spine Neurogenic/Radicular-majority of the pain is in the lower extremity usually following a specific nerve root/dermatomal pattern

Mechanical low back pain- differential diagnosis –Central disc protrusion/posterior annulus tear –Facet mediated pain –Sacroiliac joint pain –Spinal stenosis –Pars interarticularis stress fracture –Spondylolisthesis –Lumbar strain/sprain –Compression fracture –Inflammatory/infectious/tumor

Neurogenic low back/lower extremity pain Lateral disc protrusion Far lateral disk protrusion Neuroforaminal stenosis-Spondylolisthesis Spinal stenosis with neurogenic component Others-Piriformis Syndrome, Lateral Femoral Cutaneous Nerve Entrapment, Tumors, Lyme disease

Lumbar Disc Anatomy

Lumbar nerve root anatomy

Nerve root pain patterns/dermatomes

Lower extremity deep tendon reflexes Patella-L4 Achilles-S1

Lower extremity muscle strength testing -Hip Flexor L3 -Quadriceps, Anterior Tibialis L4 -Extensor Hallucis Longus L5 -Flexor Hallucis Longus S1

Indications for MRI lumbar spine Progressive neurological deficit- weakness most important Cauda equina syndrome- bowel/bladder retention/incontinence, saddle anesthesia No significant improvement with 4-8 weeks of conservative therapy/PT Severe, intractable pain Red flags- fever, weight loss, previous cancer, IV drug use

Disc protrusion patterns Central disc protrusion Lateral disc protrusion Far lateral/Foraminal disc protrusion

Central Disc Protrusion

Central Disc Protrusion General Characteristics Frequent cause of recurrent mechanical/axial low back pain in the <50 year-old Frequently injured/aggravated by flexion Pain is frequently worse with coughing, sneezing, laughing or valsalva Pain is frequently worse with prolonged sitting/long car ride Pain is frequently worse with both standing flexion and extension Pain is frequently worse with bilateral sitting straight leg raises

Central disc protrusion continued Low back pain is frequently worse with bilateral supine straight leg raising Normal lower extremity neuro exam Posterior annulus tear frequently associated with central disc protrusion as seen on MRI scan Try to treat in extension advising the patient to maintain his lordosis with bending Oral steroids/caudal or transforaminal epidural injections can be helpful Avoid diskectomy alone

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Lateral disc protrusion

Lateral disc protrusion general characteristics Lower extremity radicular pain worse than low back pain Lower extremity pain follows radicular and dermatomal pattern Pain is generally worse with coughing and sneezing, valsalva maneuvers Pain is generally worse with flexion and sitting L3-4 disc-L4 radicular pain, L4-5 disc- L5 radicular pain, L5-S1 disc- S1 radicular pain

Lateral disc protrusion continued Careful lower extremity neuro exam may be able to identify specific nerve root lesion Straight leg raising usually reproduces radicular pain Try to treat with extension to centralize pain May respond to oral steroids or transforaminal epidural steroid injections Persisting pain may need discectomy to relieve lower extremity pain

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Far lateral/foraminal disk protrusion

Far lateral/foraminal disk protrusion general characteristics Lower extremity radicular pain much worse with standing and walking, usually improved with sitting Lower extremity pain follows radicular and dermatomal pattern Usually not worsened by coughing or sneezing Careful lower extremity neuro exam may be able to identify specific nerve root involvement Increased radicular pain with lumbar Spurling’s testing

Far lateral/foraminal disc protrusion continued L3-4 foraminal disc protrusion-L3 radicular pain, L4-5 foraminal disk protrusion-L4 radicular pain, L5-S1 foraminal disk protrusion-L5 radicular pain Treat with lumbar stabilization exercises since extension usually aggravates radicular pain, consider pelvic traction Trial of oral steroid medications Frequently respond to transforaminal epidural steroid injections (selective nerve root blocks) Diskectomy can be difficult because of facet joint blocking exposure

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Facet joint pain

Facet mediated pain general characteristics Mainly mechanical/axial low back pain with occasional buttock pain Generally worse with standing and walking and improves with sitting No increased pain with coughing or sneezing Lower extremity neuro exam is usually normal X-rays and MRI show facet arthritis without focal disc protrusion

Facet mediated pain continued PT is frequently helpful for lumbar stabilization, ?pelvic traction Oral versus topical NSAIDs Medial branch block injection therapy to confirm facet mediated pain followed by radiofrequency ablation Consider fusion for instability/resistant pain

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Spinal stenosis

Low back pain with radiation to bilateral buttocks and lower extremities which is worse with prolonged standing and walking Neurogenic claudication may need to rule out vascular claudication first PT for stabilization and flexibility Caudal epidural steroid injections Surgical decompression for resistant cases

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Pars interarticularis stress fracture Very common cause of low back pain in young athlete less than 25 years old Worse with extension, stork test Normal lower extremity neuro exam MRI probably best test versus SPECT bone scan, consider CT scan to look for spondylolysis Removal from offending activity until symptoms improve PT for hamstring flexibility and abdominal strengthening Bracing? Bone stimulator?

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