Ch. 13 - Low back pain and leg pain Flashcards
What is the critical factor in assessing pts with low back pain?
Whether there are features of lumbosacral nerve root compression
What is sciatica?
Clinical description of pain in leg 2/2 lumbosacral nerve root compression
Most common cause of sciatica
Lumbar disc prolapse causing nerve root compression Other: osteophyte compression, lumbar canal stenosis, spondylolithesis
Most common level of lumbar disc prolapse
L5/S1
Components of interverterbal disc
Internal nucleus pulposus surrounded by annulus fibrosus (external laminar fibrous container)
Disc prolapse is most common in what direction?
Posterolateral direction b/c posterior longitudinal ligament prevents direct posterior herniation
An L4/5 POSTEROLATERAL disc prolapse will compress which nerve root?
L5
An L5/S1 POSTEROLATERAL disc prolapse will compress which nerve root?
S1
An L4/5 LATERAL disc prolapse will cause compression of which nerve root?
L4
Describe the different types of disc prolapse
A) Posterolateral disc prolapse -> compression of nerve root below
B) Lateral disc prolapse -> compression of nerve root above
Features of L5/S1 disc prolapse
Pain along posterior thigh with radiation to heel
Plantar flexion weakness
Lateral foot sensory loss
Absent ankle jerk
Features of L4/5 disc prolapse
Pain along posterior or posterolateral thigh with radiation into dorsum of foot and great toe
Dorsiflexion weakness
Decreased sensation of dorsum of foot and great toe
No reflex changes
Features of L3/4 disc prolapse
Pain in anterior thigh
Quadricep (with quadricep wasting) and dorsiflexion weakness
Decreased sensation over anterior thigh, kknee, and medial aspect of lower leg
Reduced knee jerk
Innervation of hip flexors? Extensors?
Flexors - L1, 2, 3
Extensors - L5, S1
Innervation of knee flexors? Extensors?
Flexors - L5, S1
Extensors - L3, 4
Innervation of ankle dorsiflexors? Plantar flexors?
Dorsiflexors - L4, 5
Plantar flexors - S1, 2
How long do most cases of back and leg pain take to resolve?
7-10 days
What should you order for evaluation of back/leg pain?
X-ray to diagnose associated spondylolisthesis and exclude sinister pathology (e.g. spinal mets)
ESR to exclude systemic dx
What are the indications for surgical intervention in disc prolapse?
Incapacitating pain, continuing episodes of recurrent pain, neurologic deficit (e.g. weakness), bilateral sciatica (suggests central disc prolapse), tumor
Imaging study of choice for disc prolapse?
MRI
Surgical options for lumbar disc prolapse
Usually partial laminectomy + disc excision
Percutaneous lumbar discectomy (remove nucleus pulposus) for ‘bulging’ disc
Criteria that suggest better results following disc prolapse surgery
Good hx of sciatica, good signs of nerve root irritation, evidence of herniated disc, nerve root stretched by disc at time of surgery, pt is motivated
Characteristic feature of lumbar canal stenosis
Pain is relieved with sitting (‘shopping cart’ sign)
What are the most common levels affected by lumbar canal stenosis?
L4/5 and L3/4
Surgical tx of lumbar canal stenosis
Decompressive lumbar laminectomy
What intra-abdominal pathology should be considered in a patient with back pain?
Pancreatic dx - pancreatitis or tumors
Aortic aneurysm
Renal dx - calculus, infection, tumor
What is spondylolisthesis?
Subluxation of one vertebral body on another (usually L4 or L5); can be congenital or 2/2 degenerative changes
Tx of spondylolisthesis
Conservative therapy, laminectomy +/- spinal fusion
Symptomatic patients with grade 2 or above slip have a clear benefit with surgery!
