Serratus plane block: a novel ultrasound-guided thoracic wall nerve block

Anaesthesia 2013;68:1107-1113 doi:10.1111/anae.12344

Presented by: Dr. A. Gańska

Background

  • The serratus plane block is an alternative block to paravertebral block and thoracic epidural (which are more challenging and have higher potential side-effect profile
  • It can provide a long lasting analgesia for breast, axilla surgery and prevention of acute pain progressing to chronic pain
  • It has fewer side-effects, is safe and easy to perform

Design and Settings

  • Descriptive study on 4 volunteers and 3D reconstruction of local anaesthetic spread using fat-suppression MRI imaging

Subjects

  • 4 female volunteers

Intervention

  • USS guided injections, two per volunteer of solution of 0.4ml/kg 0.125% levobupivacaine mixed with 0.1mmol/kg gadolinium.
    • First superficial to serratus anterior
    • Second underneath the muscle at level of 5th rib in midaxillary line.
  • Thoracodorsal artery was used as an extra reference point

Outcomes

  • Test of sensory loss after 30min with hypodermic needle
  • MRI scan after 1h to show distribution of gadolinium
  • Two observers compared images with MRI atlases

Results

  • T2 – T9 dermatomal paresthesia
  • Weak crossed-arm adduction movement

Conclusions

  • injection I: 752min duration of paresthesia for sensory nerves and 43min for motor nerves
  • Injection II: 386min duration of paresthesia for sensory nerves and 150min for motor nerves
  • MRI showed good spread with both injections

Study limitations

  • Descriptive study on volunteers
  • Small number of participants
  • Needs randomised controlled trial
  • MRI distribution of gadolinium may mimic fat tissue, image analysis software had to be used
  • Possibility of false impression of extent of LA spread – there was greater extension of the clinical effect then MRI suggested

Potential for impact

  • The serratus plane lock appears to give predictable and long lasting regional anaesthesia
  • Alternative to surgical LA infiltration, paravertebral blocks, thoracic epidural and intercostal nerves blocks
  • Compared with above this technique could be better for day case surgery
  • Superficial block was more effective