Session O3D1: Use of ultrasound in spinal and epidural anaesthesia: pro-con debate

Session O3D1: Use of ultrasound in spinal and epidural anaesthesia: pro-con debate

Saturday 2 June, 11h00-12h00, Auditorium 11

Another fascinating pro-con debate session during today’s Euroanaesthesia sessions will be on the use of ultrasound in spinal and epidural anaesthesia.

Dr Gabriella Iohom, Cork University Hospital and University College Cork, Ireland, will deliver the pro part of the debate, saying that ultrasound (US) guidance has revolutionised regional anaesthesia, particularly peripheral nerve blockade.

She says: “It is undoubtedly less popular for central neuraxial blockade (spinal, epidural) due to the efficacy of the landmark technique and the limitations of the ultrasound of the adult spine, namely that visualisation of the structures encased within the bony vertebrae is possible only through the interlaminar spaces.”

However, she adds that this argument also shows the utility of US in neuraxial blockade: that is, if it is possible to shine an US beam through an acoustic window, it is also possible to direct a needle through that interlaminar space.

Dr Iohom will argue for incorporating preprocedural US into one’s practice so that it is available for difficult cases. She will present the evidence as to its proven utility in:

  1. Identifying internal landmarks (midline, intervertebral level)
  2. Measuring depth-to-target distance
  3. Improving clinical efficacy
  4. Improving technical performance
  5. Predicting the feasibility of neuraxial blockade in anticipated difficult cases (preoperative assessment)

She says: “I am then going to ‘demolish’ the perceived barriers to the routine use of US for neuraxial blockade, such as lack of expertise and evidence-based curriculum, financial and time constraints, and equipment availability.”

Finally, Dr Iohom will discuss existing guidelines (NICE 2008, ASRA 2016) and future directions. Through analogy with fibreoptic intubation, one should gain proficiency in routine cases before approaching the difficult ones. She concludes: “Future trainees will likely become so familiar and relaxed with US technology (dubbed ‘the new stethoscope’) that it will be inconceivable to them not to use it for neuraxial blockade — the same way as currently they would not attempt a central venous catheter insertion without US.”

Dr Eric Albrecht, Lausanne University Hospital, Switzerland, will deliver the ‘con’ part of the debate. He will say that surface anatomic landmarks enable physicians to identify the correct intervertebral space only in 30% of the cases. He says: “This is probably one of the reasons why the National Institute for Health and Care Excellence (NICE) in the United Kingdom highly recommends the use of US for spine procedures.”

Interestingly, while the first description of US-guided peripheral nerve block dates from 1989 on a case series of 10 patients with an axillary brachial plexus block, the first paper that reported the use of ultrasound to localise the lumbar space on 36 patients was reported 10 years earlier. Despite the NICE recommendations, and the early description of US-assisted spine procedure 40 years ago, a survey showed that 97% of the UK anaesthetists still do not use US to facilitate neuraxial procedures, even if 60% of them were properly taught by experts. The reasons are many: complex US procedures with different views to picture; a steep learning curve; images difficult to interpret in obese patients, in patients with a history of spine surgery, or patients with scoliosis; or that it can be a time-consuming procedure when compared with anatomic landmarks.

Dr Albrecht says: “Furthermore, the procedure is usually US-assisted and not US-guided, which means that the US can only help the physician to identify the needle insertion site and not to visualise the progression of the needle within the tissues during a real-time procedure. Of course, there are some experts that can perform a real-time US-guided neuraxial procedure, with only two hands, but these reports are performed on slender patients, on whom the procedure would be very easy without US.”

Indeed, Ansari and colleagues showed recently in the International Journal of Obstetric Anesthesia that when neuraxial blocks were performed by anaesthetists experienced in both US and landmark techniques, the use of US does not increase the success rate of spinal anaesthesia, or reduce the number of attempts in patients with easily palpable spines. Dr Albrecht concludes: “These are the reasons why US has not widely spread in the routine practice of neuraxial blocks, despite the NICE recommendations.”