Ultrasound guided lower limb blocks Dr Anthony Allan Great Western Hospital

1
Ultrasound guided lower limb blocksDr Anthony
AllanGreat Western Hospital
2
Overview of lower limb nerve blocks

• Femoral
• Saphenous
• Sciatic
• Subgluteal approach
• Popliteal approach
• Tibial

• Anatomy/sonoanatomy
• Block conduct
• Tips and clips

3
Lower limb ultrasoundgeneral points

• Pattern recognition practice
• Proximal fat distribution and block conduct
  variability in probe/needle choice

4
Femoral anatomy
5
Sonoanatomy of femoral nerve

• Hyperechoeic honeycomb architecture
• Suprainguinal - oval 67, triangular 33
• Infrainguinal oval 95, triangular 5
• Average 10 mm by 3 mm

6
(No Transcript)
7
Femoral nerve block

• Patient Supine, leg laterally rotated
• Probe High frequency placed transversely just
  below inguinal ligament
• Needle Dependant on approach/depth, 50-100mm

8
(No Transcript)
9
US guided femoral block

• Improves block onset time to 31 block
• Improves quality of block

  Ultrasound Nerve stimulator
Onset time 16/- 14 min 27/-16 min
31 Block 95 85
21 Block 0 5
No block 5 10
10
Tips

• Variable distance from vessels
• Splits into terminal branched 0-5cms below
  inguinal ligament
• If deep - IP approach - place nerve on opposite
  side of screen to needle entry

11
Saphenous nerve anatomy/sonoanatomy

• Cutaneous branch of post div of femoral nerve
• Leaves adductor canal to emerge between sartorius
  and gracilis
• Runs down medial aspect of leg with and
  immediately posterior and slightly deep to great
  saphenous vein
• Seen as small speckled nerve bundle

12
(No Transcript)
13
Saphenous nerve anatomy
14
Saphenous nerve block

• Patient Supine, knee slightly flexed, leg
  externally rotated
• Probe High frequency placed transversely over
  medial aspect lower thigh
• Needle 50mm

15
(No Transcript)
16
Tips

• Can be v difficult to visualise
• Perivascular inj around great saphenous vein at
  level of tibial tuberosity

17
Sciatic nerve block subgluteal approach

• Subgluteal space potential space
• Roof - Gluteus maximus then biceps
• Floor - Gemellus superior, obturator internus,
  gemellus inferior, quadratus femoris, adductor
  magnus
• Contains
• Sciatic and Post cut nerve of thigh
• Inferior gluteal AV

18
(No Transcript)
19
(No Transcript)
20
Sonoanatomy

• Flat/oval hyperechoeic band
• Up to 1.5-3cms wide
• May see post cut nerve of thigh

21
(No Transcript)
22
Sciatic nerve block subgluteal approach

• Patient - Lateral, hips and knees flexed
• Probe low frequency, sector array placed
  transversely at level of line dividing greater
  trochanter ischial tuberosity
• Needle 100mm

23
(No Transcript)
24
Tips

• Depth makes needle visualisation more difficult
• ? Better view distally below biceps
  (infragluteal)
• Helpful to use in conjunction with NS

25
Sciatic nerve block popliteal approach
26
Sciatic nerve block popliteal approach
27
Sonoanatomy

• 1 large or 2 smaller nerve bundles under biceps
• Tibial n larger, medially in front of pop v a
• Common peroneal n smaller, moves laterally
  following medial border of biceps to neck of
  fibula, possible to see sural com branch

28
(No Transcript)
29
Sciatic nerve block popliteal approach

• Patient position prone or supine with knee
  flexed
• Probe Mid/high frequency, transversely proximal
  to popliteal crease angled slightly caudad
• Needle 50/100 approach/depth dependant,

30
(No Transcript)
31
Tips

• Plantar/dorsiflexion of foot seesaw sign
• Separate tibial and common peroneal injections
  when
• nerve divides proximally
• nerve v deep - allows more distal injection where
  nerve is more superficial
• If doing IP approach
• consider true lateral approach
• inject to deep surface first

32
Tibial nerve anatomy
33
Sonoanatomy

• Structures visible from ant-posterior
• Tibia
• Tendon of tibialis posterior
• Tendon of flexor dig longus
• Post tibial a vs
• Flexor hal longus soleus
• Achilles tendon
• Tibial nerve speckled appearance, may have
  already divided

34
(No Transcript)
35
(No Transcript)
36
Tibial nerve block

• Patient supine, legs crossed distally and ext
  rotated
• Probe high frequency placed transverse just
  above medial malleolus
• Needle 50mm

37
(No Transcript)
38
(No Transcript)
39
References

• Marhofer P, Greher M, Kapral S. Ultrasound
  guidance in regional anaesthesia. Br J Anaesth
  2005 94 7-17
• Marhofer P, Schrogendorfer K, Koinig H et al.
  Ultrasonographic guidance improves sensory block
  and onset time of three in one blocks. Anesth
  Analg 1997 85 854-7
• Lundblad M, Kapral S, Marhofer P, Londqvist P.
  Ultrasound-guided infrapateller nerve block in
  human volunteers description of a novel
  technique. Br J Anaesth 2006 97 710-14
• Karmarker M, Kwok W, Ho A et al.
  Ultrasound-guided sciatic nerve block
  description of a new approach at the subgluteal
  space. Br J Anaesth 2007 98 390-5