Compression Neuropathy Flashcards
Neuropathy
functional or pathologic changes in the peripheral nervous system
Compression neuropathy
-process whereby a nerve becomes entrapped as it passes through a narrow tunnel or passage
Pathological changes that occur with neuropathy include
- microvascular compression–>ischemia
- thickened epineurium
- myelin thinning distortion
- microtubule closure
- axonal degeneration
Etiology of Nerve Entrapment
- increased muscle mass by repetitive activity
- space occupying lesions (cysts or tumors)
- inflammation of surrounding tissues leads to venous congestion in epineurial and perineurial vascular plexuses–>endoneurial edema–>nerve anoxia
- Post traumatic conditions (hematoma, fracture, or compression by equipment)
- systemic causes–pregnancy, hypothyroidism or diabetes, etc.
Neurapraxia
- least severe nerve injury
- involves focal damage of myelin fibers around axon, but the connective tissue sheath remains intact
- limited course (days to weeks0
Axonotmesis
- injury to the axon itself
- regneration is possible, but prolonged (months) without full recovery
Neurotmesis
-complete disruption of the axon with little likelihood of recovery
Conservative measures for compression neuropathy include
- modification of activity, use of antiinflammatories, splinting, and/or injections
- PT, OMM, pain management
- should be pursued for 3-6 months (except with cubital tunnel syndrome)
- surgical release is considered when nonoperative management fails
Cervical Nerve Root Compression
- usually caused secondary to cervical disc disease (i.e. disc bulging or herniation)
- most commonly the disc ruptures posterior-laterally using compression of the nerve root as it exits the intervertebral foramen
- causes radiculopathy–pain caused by compression of the spinal nerve that radiates in the distribution of the defined nerve root
C5
- deltoid, biceps motor
- sensation to lateral arm
- biceps reflex
C6
- wrist extension, elbow flexion
- sensation to radial forearm, thumb and index finger
- brachioradialis reflex
C7
- wrist flexion, elbow extension, finger extension
- sensation to middle finger
- triceps reflex
C8
finger flexion
-sensation to ulnar forearm, small finger
T1
- Finger abduction
- sensation to medial arm
Peripheral Nerves at Risk in the upper extremity
- radial nerve
- median nerve
- ulnar nerve
- musculocutaneous and axillary
Radial Nerve Entrapment Sites
- High on the humerus
- radial tunnel
- at the wrist
Radial Nerve Function
- motor to triceps brachii, anconeus, wrist extensors
- sensation to majority of the dorsum of the hand (via posterior interosseous nerve)
Radial Nerve Entrapment High on the humerus
- usually secondary to a humorous fracture or compression of nerve near spinal groove
- symptoms: wrist drop, weakness of elbow flexion (brachioradialis), possible triceps involvement, +/- triceps reflex diminished, pain and numbness
- Treatment: function usually returns in 4-5 month
Radial Nerve Entrapment: Radial Tunnel Syndrom
- compression of posterior interosseous branch of the radial nerve as it passes under the supinator muscle at the Arcade of Frohse (purely motor branch)
- Supinator syndrome
- repetitive rotatory movements–>rowing, discus, racquet sports
- heavy manual labor
- symptoms: pain and tenderness 5 cm distal to lateral epicondyle
- wrist drop or pain with resisted supination
Median nerve Entrapment sites of entrapment
- ligament of Strutters
- Pronator Syndrome
- Anterior Osseous Syndrome
- Carpal Tunnel Syndrome
Median Nerve functions
- forearm flexion and pronation
- wrist flexion and radial deviation
- thumb abduction and opposition
- index and middle finger abduction and flexion
Median Nerve Entrapment: Pronator Syndrome
- occurs as the median nerve passes between the superficial and deep heads of the pronator teres muscle
- seen with repetitive pronating motions: pianists, fiddlers, baseball players, dentists, weight trainers, etc.
- symptoms: achy pain in the mid/proximal forearm, aggravated by repeated lifting
- may have sensory abnormality in the radial three and a half digits
- pain with resisted forearm pronation
Median nerve entrapment: Anterior Interosseous syndrome
- deep motor branch of the median nerve
- just distal to the pronator teres
- innervates flexors
- no sensory symptoms
- trauma, cast pressure
- bulky tendinous origin of ulnar head of pronator teres
- soft tissue masses
- fibrous band
- treatment: general, and elbow can be splinted in 90 degrees of flexion for up to 12 weeks
- If patient unable to hold and rest OK sign
- due to weak flexion ability of the index finger’s DIP and the thumb’s IP
Median Nerve Entrapment: Carpal tunnel syndrome
- most common compression syndrome
- compression as nerve passes with flexor tendons under the flexor retinaculum
- nighttime numbness of lateral 3 1/2 digits, tingling, wrist pain, dropping things, thenar atrophy
- common in repetitive motion jobs (wrist flexion) and in pregnancy
- diagnosis gold standard is EMG
Carpal tunnel Diagnosis
- Phalen’s–flex hands to 90 degrees, reproduction of symptoms within 60 seconds is positive sign
- tinel’s–tapping over the flex retinaculum reproduces symptoms in the first 3.5 digits
- two point discrimination–unable to distinguish 2 points on a caliper if closer than 5 mm
Carpal Tunnel Syndrome Treatment
- rest from repetitive motions if possible and self-stretching
- wrist splinting with 30 degrees of hand extension, usually at night
- NSAIDs
- steroids injections if failure of conservative measures
- surgical release if failure of other treatments
Ulnar Nerve Sites of Entrapment
- cubital tunnel
- Guyon’s canal
Ulnar nerve function
- innervates skin and muscles of the ulnar side of the forearm and hand (flexors)
- deep branch in hand–>motor innervation for interosseous muscles and adductor pollicis
- superficial branch in hand–>sensory innervation to ring and pinky fingers
Ulnar Nerve Entrapment: Cubital Tunnel Syndrome
- most common compression seen in elbow
- compression at the cubital tunnel from by medial epicondyle, medial trochlea, olecranon, and ulnar collateral ligament
- baseball pitchers, prolonged elbow flexion (during sleep), external compression against a hard surface, thickened cubital tunnel retinaculum
Cubital Tunnel Syndrome Symptoms and Diagnosis
- parasthesia to the 4th and 5th digits
- medial elbow pain radiating to the hand with decreased intrinsic muscle strength
- can’t turn a key in a door
- positive tinel’s sign at elbow
- symptom reproduction with elbow flexion and wrist extension
Cubital Tunnel Syndrome Treatment
-general treatment, and a padded elbow sleeve to limit terminal elbow flexion and provide cushioning
Cubital Tunnel Syndrome Tests
- Froment’s sign–patient must flex thumb in order to pinch paper between 1st and 2nd digits
- must contract FPL (supplied by median n) due to weak 1st dorsal interosseous and ADP muscles (positive sign)
Thoracic Outlet Syndrome
- compression of the brachial plexus and/or subclavian vessels
- sites of compression include scalene triangle, costoclavicular passage, at the pectoralis minor attachment at the coracoid process
- weakness, paresthesia of medial arm, forearm, and hand exacerbated by overhead activities
- provocative tests: EAST, Adson’s, Wright’s hyperabduction test, Military/costoclavicular maneuver
L1-L2
- Hip flexion
- sensation to inguinal crease (L1), anterior thigh (L2)
L2-L3
- knee extension
- sensation to anterior thigh (L2), anterior thigh just above knee (L3)
L4
- ankle dorsiflexion
- sensation to medial leg and foot
- knee jerk (patellar) reflex
L5
- extensor hallucis longus
- sensation to lateral leg, foot dorsum
S1
- ankle plantar flexion
- sensation to lateral foot, plantar foot
- Achilles reflex
Lower Extremity Nerves at risk for compression neuropathy
- common fibular nerve (L4-S2)
- deep fibular nerve (L4-S2)
- posterior tibial nerve (L4-S2)
- lateral femoral cutaneous nerve (L2-L3)
Common fibular nerve
- divides into a deep and superficial branch
- deep branch innervates the anterior compartment (tibialis anterior m, extensor digitorum longus/brevis mm., and extensor hallicus longus)
- superficial branch innervates the lateral compartment (fibulas longus and brevis)
Common Fibular Nerve compression
- 3rd most common compression neuropathy
- compression as nerve winds around the fibular neck and enters the fibular tunnel
- leg hooked over rail (bedridden, comatose, post op)
- Strawberry pickers palsy–time spent in squatting position
- ankle sprains or trauma to fibular head
- new meditators (lotus position)
- lithotomy position during childbirth
- idiopathic
Common Fibular Nerve compression symptoms
- pain along proximal third of lateral leg
- foot drop with a slapping gait
- exacerbated during plantar flexion and inversion of the foot
Common Fibular Nerve Treatment
- posterior fibular head HVLA or ME
- ME on gastrocnemius/soleus, biceps femoris
Anterior Tarsal Tunnel Syndrome
- deep fibular nerve compression at the inferior extensor retinaculum
- trauma (recurrent ankle sprains, soccer players), talonavicular dysfunction, prolonged plantar flexion, compression from shoes
Anterior Tarsal Tunnel Syndrome Symptoms
- pain over dorsomedial aspect of foot and worse at rest
- weakness of extensor digitorum brevis
Anterior Tarsal Tunnel Syndrome Treatment
- remove compressive forces
- myofascial release of extensor retinaculum
- traction tug of talonavicular joint
- hiss whip for navicular, cuneiforms, 1st and 2nd metatarsal
Tarsal Tunnel Syndrome
- compression of posterior tibial nerve in the tarsal tunnel behind medial malleolus with the overlying flexor retinaculum
- motor to the plantar muscles of the foot and sensation to plantar aspect of foot and toes
Tarsal Tunnel Syndrome Etiology
- idiopathic in 50% of cases
- space-occupying lesion: synovial cyst, ganglion from tendon sheath, lipoma, tenosynovitis
- trauma to medial malleolus, distal tibia, or calcaneous (MVAs)
- congenital, autoimmmune (RA, ankylosing spondylitis)
- diabetes, lifestyle
Tarsal Tunnel Syndrome Symptoms
- pain on plantar surface of foot
- not very specific–vague burning, tingling, or numbness on plantar aspect of foot
- gait seldom affected
Tarsal Tunnel Syndrome Treatment
-myofascial release and HVLA
Lateral Femoral Cutaneous Nerve: Meralgia Paresthetica
- compression under the inguinal ligament at the inguinal canal
- very intense athletics, obesity, tight girdle/belt, tight clothing, seta belt misplacement or post-accident, anatomic anomaly
Lateral femoral Cutaneous nerve function
-sensory only of anterolateral thigh down to the knee
Lateral Femoral Cutaneous Nerve Compression neuropathy symptoms
- numbness or burning pain on anterolateral thigh
- hypersthesia to the point of not putting anything in pockets
- trophic skin changes later on
- positive Tinel’s sign 1 cm medial and inferior to the ASIS
