A Randomised Controlled Trial Comparing Needle Movements During Combined Spinal-Epidural Anaesthesia With and Without Ultrasound Assistance

Chin B, Crooke L, Heywood R et al.

Anaesthesia 2018, 73: 466-473


Aim Of Study

“To assess the efficacy of pre-procedural neuraxial ultrasound in a general obstetric population with regard to needle movements and procedural difficulty, and to identify factors associated with successful technical performance of combined spinal-epidural (CSE) anaesthesia”.

Design (& Location)

Prospective, randomised controlled trial at a single hospital in Brisbane, Australia.


Ultrasound group: anaesthetist marked optimal insertion point based on palpation, investigator then identified largest intervertebral window using ultrasound. Anaesthetist used ultrasound-derived insertion point.

Control group: anaesthetist marked optimal insertion point based on palpation, then left the room. Investigator identified largest intervertebral window, and their marks were then removed. Anaesthetist used their original planned insertion point.

Primary Outcome

  • First pass success.
  • Difficult CSE procedure.

Secondary Outcomes

  • Block quality (top-ups, supplemental analgesia, GA).
  • Intra-operative pain.
  • Patient satisfaction with CSE.


Various comparisons of categorical and continuous data, plus binary logistic regression with adjustment for multiple comparisons. Multiple pre-specified and post-hoc sub-group analyses.


Ultrasound increases first pass success, but does not significantly reduce difficult CSEs, once adjusted for multiple comparisons.

No significant differences between study arms in patient satisfaction, block quality, complications or pain.


Unlike previous studies on ultrasound-guided neuraxial blocks, this did not show a reduction in difficult CSEs.

It suggested greatest benefits if the patients’ anatomical landmarks were easily palpable, which was also contrary to earlier research.

Good communication with the patient and effective local anaesthetic infiltration may be more important than the number of times the needle is redirected.

Stated Limitations From Study

In the ultrasound group, the scan-guided insertion point was communicated to the CSE-performing anaesthetist, but not the angle of trajectory, meaning that the benefits of ultrasound might have been underestimated.

Discussion from Journal Club Meeting (? Change of practice)

CSEs make up a small percentage of central neuraxial blocks, but were implicated in a disproportionately large number of serious complications in NAP3. The relative infrequency with which they are performed, and the technical challenge of interpreting ultrasound scans of the back mean that local practices are unlikely to be changed by this study.

Summary by Dr T Wedgwood. Journal Club Meeting 05 April 2018.

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