This document discusses electrodiagnostic techniques for evaluating radiculopathy. It covers nerve conduction studies including SNAPs, CMaps, H-reflexes and F-waves. It also discusses needle EMG findings including fibrillations, positive sharp waves and complex repetitive discharges. The advantages and disadvantages of each technique are provided for assessing different nerve roots involved in radiculopathy.

2.  Origins of pain
 Clinically important tip: What likes root pain?
 Pure sensory Radiculopathy?

3.  EDX important limitation
 Axonal loss: M&S&R loss
 Conduction Block:
◦ Non- demeylinating
◦ Demeylinating: M&S&R loss
 Conduction slowing
◦ Differential: S&R loss, NCV can be normal:
◦ Synchronized
◦ EDX= extension of neurologic examination

5.  SNAP:
◦ NL>>Amp>latency
◦ C6,C7,C6&C7,C8,T1
◦ L2-L3, L4,L5,S1
 When SNAP dec?
◦ Proximal DRG (severe L5)
◦ Far lateral Herniation
◦ Gangloionopathy (Dm/ herpes)

6.  CMAP
◦ NL>Amp>absent>latency: Why?
◦ Abnormality in 6-8 days
◦ C8/T1
◦ L5/S1
◦ S1/S2

7.  H reflex:( GCS)
◦ S radiculopathy 30-100% abnormality(definition)
◦ Different pathway from ankle jerk reflex
 H reflex:( FCR)
◦ C6&C7 radiculopathy :17.4, 0.7 ms
 Advantage:
◦ sensory radiculopathy
 Disadvantage:
◦ Sensitivity&Specifity
 Abnormal H(GCS)

8.  F wave
 Fist finding in: GBS/Vasonervoum infarct
 F-wave abnormality: MMN
 Advantage:
◦ Immediately, Not readily accessible araes
 Disadvantage:
◦ Recurrent process
◦ Motor only
◦ If one root AbNl: others can mask it
◦ Dilution
◦ Non specific

9.  Nerve Root Stim.
◦ C5 SPC5&C6: BB
◦ C6 SPC5-C8:TRC
◦ C7 SPC8&T1:ADM
◦ L5 SP TA
◦ S1 SP GCS(lat)
 Abnormal: amp/ latency
 Advantage:
◦ More sensitive than EMG
 Disadvantage:
◦ Doubt in stim location, only motor, dangers

10.  Advantage:
◦ Immediately, Sensory
 Disadvantage:
◦ Not sensitive to mild lesions
◦ Variation
◦ Dilution
◦ No perfect localization
◦ mixed: multi root assessment,
◦ segmental: really uni root, cervical?
◦ Dermatomal?

11.  Advantage:
◦ Probably the highest Dx yield
 Disadvantage
◦ Motor only
◦ Not immediately
◦ Sometimes no conformation to H&PE
 Myotomal charts vs. individual innervation
 Small number of fibers involved
 Cyclical presence of Fib/PSW

12.  Fib/PSW
◦ Advantage
 Hall mark
 The most sensitive
 Before MUAP morphology change
◦ Timeframe: 1/3/-5,6 weeks. Is it questionable?
 Inc insertional activity
◦ Run of Fib/PSW 50 ms after stopping
◦ First Abnormality after denervation
◦ Don’t base your Dx.

13.  CRD
◦ Chronic phase, a few muscles: Paraspinal
 Fasciculation
◦ Chronic phase, a few muscles, not paraspinal
◦ Sometimes the only finding
◦ Rare but if myotomal then highly diagnostic

14.  Hallmark of radiculopathy: paraspinal
denervation (post. rami innervation)
 Technique:
◦ 1-2 cm ( L: 2.5) lateral&1 cm superior to SP
◦ Angel: 45,60 then withdraw
 Special technique in cervical; interspinal
 Instability?
◦ Difficult relaxation
◦ Renervation

15.  Other diseases :
 MND, Inflammatory myopathy, DM
 Trauma,
 Metastasis
 iatrogenic : myelogeraphy, LP, Rhizolysis,tomy
 Dorsal rami entrapment

16.  Paraspinal findings after operation
◦ Denervation ,anyway Can we say on “recurrence?
 Techniques:
◦ Lateral placement:
 1 & 3 cm:+ in latter recurrence(?)
◦ Semi-quantitive:
 After 1 y: < 100, if> 300-600 recurrence
 Better in limbs as might be scar in paraS
 Avoid it

17.  Myotomal denervation in first 1-2 m: Axonal
loss
 The same but after >3 m:
 ongoing or progressive
◦ High Amp
◦ Proximal muscles
 Care on hematoma

18.  MUAP abnormalities
◦ Red.Recruitment
 Practically Difficult
 Reference data
 Not very useful in
mild lesions
◦ Variability
 In acute phase
◦ Incr.Duration
 Incr.fiber
 asynchronicity
– Polyphasic
• NL
• Needs Quantitive EMG
• Must be myotomal
_ Large, polyphasic and
high duration MUAPs

19.  SFEMG:
◦ Jitter : inc
◦ Block + acute
◦ Block –  chronic
 Density
 If new symptoms in 4-6 w denervation amp
matters

20.  Low sensitivity of EMG
◦ Sensory only, Few fibers, slowly progressive,
Temporal
◦ No FP if myotomal denervation
 Imaging: low specificity
_ 30-80% of normal individuals have
abnormal MRI
 H&P/E: not “golden standard”
 So complimentary

22.  How to name disks and SNs?
◦ First (Second )disk :between C2 and C3 above
◦ Fist Spinal Nerve between C0 and C1 below
 Nerve root affection:
◦ most: C7>C6
◦ least :C8>C5

23.  C3/C4:
◦ Nerves, tension headache
 C5:
◦ SS,IS,DeL,BB,SuP,BR if + PT,FCR,ECR then C6 or
multi, Paraspinal helpful
◦ Rhomboid: Only (findings matter)
◦ If PT + : R/O isolated C5
 C6:
◦ All above, cant separate from C5; H helps

24.  C7:
◦ AnC, PT, FCR, EDC, plus: FCU& FPD
◦ H
◦ IF TrC -  R/O
 C8/T1:
◦ (FDP,ADM,PQ,APB,OPB) + Trc/EIP
◦ Radial innervated muscles: T1 Less
◦ TrC: C8 less not involved
◦ APB: T1 more

25.  Singular > Multiple
 If not singular other side
 Bilateral?
 If multiple and bilateral:
◦ Other causes
◦ Neuropathy Lower limb

26.  DDx
◦ MPS
◦ MSK
◦ Partial plexopathy
 Upper trunk
 Middle trunk
 Lower trunk
 Paraspinal and SNAP can help
 Double-crush injury
◦ If C6/C7 then R/O CTS
◦ IF C8/T1 then R/O cubital T.

27.  Uncommon , T8/T12 ( T11/T12)
 Cx:
◦ CM. CE / Myelopathy
◦ Band like chest pain> Lower pain>wekness
 ETX:
◦ DM, Trauma, herpes, V collapse, metastasis, Pott,
dislocated rib.
 EDX:
◦ EMG: paraspinal( relaxation, DM)/ Abdominal
muscles/Respiratory muscles
◦ CMAP(abdominal)
◦ SEP(most reliable)

28.  90% L5 and S1 due to mainly L4 and L5
discopathy
 L4 herniation
◦ Superiolateral: L4
◦ Posterior: L5
◦ Inferior: S1
◦ Medial: multiroot bilateral
 Other side
 Temporal issue

29.  L2/3/4 : 12%
◦ ParaS ,IlioP,AL,Gra, Quad
◦ Few nerves, all proximal muscles
 L5 :
◦ ParaS/Hip girdle/Peroenal:EHL/FHL,FDL,GCS,TP
 S1 : most common root
◦ L5 :most common disk
◦ ParaS/Hip girdle/TFL/Post calf,EDL.EHL/Foot intr.
◦ H reflex
◦ Cant separate from S2: maybe EDL onlyS1 but L5
 S2/3/4
◦ Anal sphincter/SoL/Foot inter. Always bilateral

30.  L2/3/4
◦ Diabetic amyotrophy
◦ Femoral nerve injury
◦ Obturator nerve injury
◦ Lumbar plexopathy: SNAP, paraspinal
 L5:
◦ Foot drop
 Peroenal palsy: SNAP of SPN, Block, EMG
 MND
 Plexopathy
 Peripheral polyneuropathy

31.  L2/3/4
◦ Diabetic amyotrophy
◦ Femoral nerve injury
◦ Obturator nerve injury
◦ Lumbar plexopathy: SNAP, paraspinal
 L5:
◦ Foot drop
 Peroenal palsy: SNAP of SPN, Block, EMG
 MND
 Plexopathy
 Peripheral polyneuropathy

32.  S1/S2
◦ Sciatic nerve injury
◦ Sacral plexopathy
 S2/3/4
◦ Pudendal nerve injury