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Epidural Anaesthesia: Images, Problems and Solutions

2011 Edition, December 30, 2011

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Active, Most Current

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ISBN: 978-1-4441-5604-1
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Product Details:

  • Revision: 2011 Edition, December 30, 2011
  • Published Date: December 30, 2011
  • Status: Active, Most Current
  • Document Language: English
  • Published By: CRC Press (CRC)
  • Page Count: 146
  • ANSI Approved: No
  • DoD Adopted: No

Description / Abstract:


Every anaesthetist undertaking epidural blocks, whether in the fields of obstetrics, surgery or pain relief, will meet with the occasional case of complete or partial block failure and, more rarely, cases with unexplained complications, which may be life-threatening. In these situations it is surely incumbent on the individual practitioner to determine the reason for the failure or complication, rather than merely accepting a poor or uncertain outcome, with disinterest, a shrug of the shoulders, and a lame excuse to the patient. Furthermore, it is becoming increasingly likely that an individual who has suffered unnecessary pain or stress as a result of an unsatisfactory or complicated block will demand an explanation as to exactly what transpired, and the threat of medico-legal action may loom.

The technique of epidurography can usually provide the answer as to the cause of block failure or a complication. With a simple, safe, contrast injection and straightforward X-ray examination, which can be completed within 10 min even in the most basic of radiology departments, the underlying problem may, in the vast majority of cases, be clearly expounded to the reassurance of both practitioner and patient.

Epidurography has been employed in 178 cases, initially at the Royal Hospital for Women, and then at the Prince of Wales Private Hospital, in Sydney. Following a pilot study of a few successful blocks to establish the characteristics of a typical epidurogram, cases of failed or complicated blocks were kindly referred to us by our anaesthetic colleagues for investigation. The results of the first 100 studies were published in An Atlas of Epidurograms: Epidural Blocks Investigated (1998). In the subsequent 13 years, an additional 78 obstetric patients have been studied with epidurography. This book includes the most significant findings from the whole series, with some of the images being reproduced from the initial work, with greater clarity than previously. Our knowledge of why epidurals fail or lead to complications has advanced considerably. Particularly revealing has been the demonstration of two separate spaces in the subdural region, one previously unrecognized by anaesthetists, but now designated as the ‘intradural space'. Our findings have allowed us to explain many previously baffling outcomes following atypical blocks.

Minor degrees of scoliosis, of which the patient is often unaware, seem to be a common cause of unsatisfactory epidurals in labour, especially when the current low-dose blocks are used. Our radiographs have revealed many cases of spina bifida occulta and we have attempted to demonstrate a connection with failed or complicated blocks. As our expertise and data have increased, it has become obvious that some of our previous radiographic findings had been incorrectly interpreted, and the astute reader will no doubt detect the reclassification of some images from the ‘Atlas'.

The epidurogram technique has been described in some detail, with two objectives in mind. First, in the hope that this information and our results will encourage our colleagues to undertake their own radiographic studies when faced with failed or complicated blocks, and second, to provide a reference work to assist in the interpretation of the radiographs obtained. Unfortunately, the vast majority of radiologists have little interest in epidurograms, and virtually no experience in assessing them, as the procedure is not used in current routine diagnostic practice. As a result, in the past, some of the reports on post-block epidurograms have been unreliable, regrettably even in many published cases. Consequently, it would be desirable for all regular users of epidural block to become familiar with the whole range of normal and abnormal appearances following contrast injection and epidurography.