ICL 6.1: LE Radiculopathies, Plexopathies & Entrapment Flashcards
what are some of the common causes of lower extremity radiculopathies?
- herniated nucleus pulposus
typically seen below 50 years of age
- spinal stenosis (narrowing of spinal canal)
typically seen above 50 years of age
what are some of the uncommon causes of lower extremity radiculopathies?
“Hi Madam”
H – Herpes Zoster
I – Inflammtory: TB, Lyme disease, HIV, syphillis, cryptococcus, sarcoidosis
M – Metastasis
A – Arachnoiditis: myelogram, surgery, steroids, anesthesia
D – Diabetes Mellitus
A – Abscess
M – Mass: meningioma, neurofibroma, leukemia, lipoma, cysts, hematoma
what is the most common lumbosacral nerve root affected in lumbosacral radiculopathies?
L5 and S1
this is because your L5 and S1 are a transition zone between different vertebrae and they receive a lot of force
what’s the clinical presentation of a herniated disk?
often sudden onset
exacerbated with: Sitting, coughing or sneezing
radiating pain down a limb (not usually back pain)
sensory changes along a dermatome – numbness, tingling, loss of sensation
some complaints of motor weakness
a dis herniation at L4-L5 that is described as a far lateral disc herniation will affect which nerve root?
L4
it’s L4 because it’s a lateral type and not a central type
UNDERSTAND THIS; QUIZ QUESTION
what spine movement is most consistent with disc herniation?
flexion
pain with flexion of the spine is more likely to be a disc herniation
what do you do during a PE when looking for radiculopathy of the LE?
Spine inspection
Spine movement – flexion, extension, rotation and lateral side bending
Manual muscle testing
Sensory examination
Deep tendon reflexes
Provocative maneuvers aka Neural tensions signs
what is the slump test?
looking for a radiculopathy
it’s performed with the patient in a flexed seated position and their arms behind their back if possible
examiner passively raises leg to full knee extension with ankle dorsiflexion
the test is considered positive if pain radiates into ipsilateral limb – they get tingling, burning, etc. down the leg to the toes
what is the straight leg raise test?
used to test for radiculopathy
patient is laying supine
examiner passively raises leg (hip flexion) with full knee extension
the test is considered positive if pain radiates into ipsilateral limb
cross reference this with the slump test
what is the reduced reflex, weakness and numbness associated with an L4 nerve root radiculopathy?
reduced reflex in patellar tendon
weakness with knee extension and ankle dorsiflexion
numbness in the anterolateral thigh/medial ankle
what is the reduced reflex, weakness and numbness associated with an L5 nerve root radiculopathy?
reduced reflex in the hamstring
weakness with hallux extension
numbest in the posterolateral thigh/calf and dorsal foot
what is the reduced reflex, weakness and numbness associated with an S1 nerve root radiculopathy?
reduced reflex with the achilles tendon
weakness with plantar flexion (patients will say they have weakness walking or pushing the gas pedal)
numbness in the posterior thigh/calf and lateral ankle
what defines a radiculopathy
weakness in muscles that are innervated by two different peripheral nerves coming from the same nerve root
how can you differentiate between an L4 radiculopathy and femoral nerve neuropathy?
adductor muscles which are L4 and are innervated by the obturator nerve, NOT the femoral nerve
what muscle is good to test for L5 radiculopathy?
- gluteus medius
have them abduct their hip to see if there’s any weakness
- tibialis anterior
- medial hamstring
- tibialis posterior
- peroneus longus
what muscle is good to test for an S1 radiculopathy?
- gastrocnemius
have them lay down and tell them to push down and plantar flex while resisting you
- gluteus maximus
test hip extension by laying them supine and asking them to dig the heel into the bed while you’re trying to lift the heel off the bed
what muscle is good to test for an L1 or L2 radiculopathy?
- iliopsoas
2. iliacus
what muscle is good to test for an L4 radiculopathy?
- adductor longus
- vastus medialis
- rectus femoris
what workup would you do if you think someone has a radiculopathy?
- Plain films – overused? When is it too early?
- MRI – excellent sensitivity for disc herniation diagnosis
- CT scan – sensitivity increases with myelogram
- electrodiagnostics - really sensitive for radiculopathies!
how does an electrodiagnostic test work?
you should examine at least 5 peripheral muscles and the paraspinals
requirement: findings in 2 separate muscles innervated by 2 separate nerves with a common nerve root
know the myotomal maps
paraspinals are affected first
how do you treat radiculopathy?
- rehab
- surgical
- epidural steroid injections (more for leg pain)
what is a lumbosacral plexus?
it consist of two separate parts: the lumbar and the sacral plexus lying above and below the pelvic rim, respectively,
they are connected by the so-called lumbosacral trunk
the lumbar part of the plexus lies embedded between and in the paraspinal quadratus lumborum and psoas muscles
the sacral plexus lies within the pelvis
L1-L4 = thigh problems
L4-sacral plexus = knee and below problems
which nerve roots are your lumbar plexus?
Nerve fibers originating from ventral rami of L1, L2, L3 & L4
which nerve roots are your sacral plexus?
Nerve fibers origination from ventral rami of L4, L5, S1, S2, S3 & S4
what are the anterior and posterior divisions of the lumbar plexus?
anterior division = obturator nerve
posterior division = femoral nerve, lateral femoral nerve, and cutaneous nerve
what are the anterior and posterior divisions of the sacral plexus?
anterior division = tibial portion
posterior division = common perineal nerve
what are some of the common causes of LSPs?
- tumor
- infection
- trauma
- obstetrics
- radiation
- hematoma
- vascular lesions
- inflammatory/microvasculitis
how can neoplasms cause lumbosacral plexopathy?
this is the most common cause of non-traumatic lumbosacral plexopathy
patients will complain of subacute onset of pain followed by motor and/or sensory loss in a distribution dependent on which area of the plexus is affected
major differential diagnoses of neoplastic lumbosacral plexopathy include:
Local pelvic bone infection (osteitis pubis)
Avascular necrosis of the hip
Radiation-induced plexopathy
predominant types = direct malignancy, metastases, intra-neural lymphomatosis, perineural spread of prostate cancer, primary nerve sheath tumors, intraneural perineurioma
which types of cancers are more likely to cause a lumbosacral plexopathy?
- direct extension
colorectal, uterine, prostate, ovarian
more proximal –> lumbar plexus more often effected
- distant metastatic cause
breast, sarcoma, thyroid and testicular
tends to effect sacral plexus more often
- radiation vs. cancer infiltration
patients will complain of weakness, leg pain
what is the key presentation symptom to differentiate between a neoplastic plexopathy vs. a radiation plexopathy?
pain
radiation plexopathy doesn’t cause any pain while neoplastic plexopathies are painful
how can a hematoma cause a LSP?
hematoma will compress the plexus as it passes through the iliopsoas muscle
patients are usually on heparin that leads to this hemorrhage
look for unexplained anemia in the CBC or Grey Turner’s sign (confirm with CT)
patients usually complain of abdominal, back or groin pain that’s constant ; they may also complain of pain going down the leg
more often effects the lumbar plexus
how can infection cause a LSP?
local more common = infection/abscesses in psoas and gluteal musculature, retroperitoneal space, infection in nearby organs such as gastrointestinal or urinary tract, or lumbar spine
systemic = varicella zoster virus, mycobacterium tuberculosis (Pott’s disease), HIV, and hepatitis C
symptoms = pain/neurological symptoms are similar to neoplasm, with symptoms such as fever, malaise, point tenderness, weight loss, and night sweats also being common
how can obstetrics cause LPS?
- difficult delivery
will effect lumbar plexus more often or maybe the femoral nerve
patients will complain of leg weakness post delivery
overall good prognosis though because the injury is so proximal to the muscle involved so they heal really fast
how do intravascular injections cause LSP?
injections should be lateral but sometimes if they’re more medial you can cause vasospasms of the lumbar plexus
if it’s severe you can get ischemic changes or gangrene around the iliac crest
what is diabetic plexopathy?
more common in the lower extremity than upper extremity but it can technically happen in both
more common in 50s and 60 years old
patients will complain of anterior thigh pain and proximal leg weakness (quads), severe aching or burning and lancinating pain
patients will also often have diminished or absent patella reflex
may see muscle wasting
will diabetic amyotrophy improve with blood sugar control?
aka diabetic plexopathy
it’s true!
what is traumatic LSP?
usually severe, very high velocity and energy at the time of impact –> often associated with pelvic fractures
ex. high-velocity car accident, gunshot wound, and traumatic dislocation of the hip
predominantly involving lower (sacral) portion, particularly at the major branches of the sciatic nerve (fibular > tibial)
common fibular > gluteal > tibial > obturator
what would you do during a PE if you’re looking for a LSP?
- observation: bruising (hematoma), skin changes, muscle bulk atrophy, fasciculations (muscle twitching)
- palpation – determine severity of pain
3. thorough neuromuscular exam: AROM and PROM Strength testing Sensory loss DTR Tone
- gait, balance
- UMN vs LMN signs
Clonus/Babinski
how do you treat LPS?
- neuropathic pain meds
- therapyL straightening, gait training, contracture prevention
- remove the problem if it’s a hematoma
- surgery
what nerve roots are associated with the lateral femoral cutaneous nerve?
L2 and L3
specifically the posterior division of the lumbar plexus
so it innervates your lateral thigh
what is a lateral femoral cutaneous nerve entrapment called?
neuralgia paresthetica
what causes lateral femoral cutaneous nerve entrapment?
- repeated low grade trauma
- protuberant abdomen (like construction workers tightening their tool belt)
- pregnancy
- tight clothing
- diabetics
- tumor infection
what are the symptoms of lateral femoral cutaneous nerve entrapment?
pure sensory syndrome!
pain, numbness, burning, dull ache
exacerbated w/ hip extension or flexion, prolonged sitting/squatting, or driving
how do you treat lateral femoral cutaneous nerve entrapment?
rehab
NSAIDS
cortisone injections
surgical release
removal of compressive clothing
which nerve roots are associated with your femoral nerve?
L2, L3, L4
posterior division of the lumbar plexus
innervates the anterior part of your thigh
what could cause a femoral nerve entrapment?
trauma, fracture, retroperitoneal hematoma, tumor, inguinal ligament compression, or cardiac catheterization
most common = iatrogenic from abdominal or pelvic surgery
what are the symptoms of a femoral nerve entrapment?
- weakness of knee extension (quads)
- knee instability
- decreased sensation over whole anterior thigh and medial leg
hip flexion weakness if above inguinal ligament
what nerve roots are associated with the sciatic nerve?
L4, L5, S1, S2, S3
posterior division of the lumbosacral plexus
innervates your posterior thigh
what’s another way to say peroneal nerve?
fibular nerve
fibular nerve makes up the outer 2/3 of the sciatic nerve
what are some causes of sciatic nerve entrapment?
hip trauma
hip replacement
injection
hematoma
pelvic fracture
penetrating wounds
gravid uterus
what is piriformis syndrome?
related to sciatic nerve entrapment and your piriformis muscle which is right above your sciatic nerve
the piriformis can become really tight and spasm and compress the sciatic nerve!
which lower limb muscles are dually innervated?
- pectineus
- adductor magnus
- biceps femoris
which nerves innervate the pectineus?
- femoral
2. obturator
which nerves innervate the adductor magnus?
- sciatic (tibial)
2. obturator
which nerves innervate the biceps femoris?
- sciatic nerve (tibial = long head)
2. sciatic nerve (fibular = short head)
what are the roots of the tibial nerve?
L4, L5, S1, S2
sciatic nerve becomes the tibial nerve
the tibial nerve then branches at the popliteal fossa to officially form the tibial nerve
what is the most common entrapment location of the tibial nerve?
the tarsal tunnel
the tibial nerve will be compressed underneath the flower retinaculum (which runs from the calcaneus to the malleolus)
what symptoms are associated with tibial nerve compression?
- intrinsic foot weakness
- perimalleolar pain
- numbness and paresthesias reproduced by ankle inversion
- positive Tinel’s
heel sensation is fine though!!!
what goes through your tarsal tunnel?
Tom Dick And Very Nervous Harry
Tibialis posterior
flexor Digitorum longus
posterior tibial Artery
posterior tibial Vein
tibial Nerve
flexor Hallucis longus
what are the nerve roots of the common peroneal nerve?
L4-S2
it’s a branch of the sciatic nerve that winds around the fibular head into the deep and superficial portions
what does the superficial peroneal nerve innervate?
- peroneus longus and brevis
2. medial and lateral cutaneous nerve
what does the deep peroneal nerve innervate?
everything else
- tibialis anterior
- extensor digitorum longus
- extensor hallucis longus
- peronenus tertius
- extensor digitorum brevis
- first dorsal interossei
- dorsal distal cutaneous nerve
what is the cutaneous innervation of the deep peroneal nerve?
the first and second webspace of the foot
what is the cutaneous innervation of the superficial peroneal nerve?
the anterior lateral part of the leg
what is a common entrapment site for the peroneal nerve?
the fibular head
if it’s high enough in the fibular nerve it can knock out both the superficial and deep fibular nerve branches
what causes peroneal nerve entrapment?
- compression from prolonged leg crossing
- weight loss
- poor positioning during surgery
- poor cast application
- prolonged squatting position (strawberry pickers’ palsy)
- metabolic disorders such as diabetes
what are the symptoms of peroneal entrapment?
- complains of the weakness of the dorsiflexors (TA, EDL, EHL)
- foot drop
- foot slap
- steppage gait
- it’ll involve all the muscles supplied by the deep and superficial branches of the common fibular nerve
the short head to eh biceps femoris is spared
though
what are the common entrapment neuropathies of the lower extremity?
- lateral femoral cutaneous neuropathy
- femoral neuropathy
- peroneal neuropathy
- tarsal tunnel
all of these may cause foot drop except for:
A.
common peroneal neuropathy
B. L4 radiculopathy
C. L5 radiculopathy
D. lumbosacral plexopathy
E. ALS
D. lumbosacral plexopathy
with ALS one of the first signs is actually a foot drop!
