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Liver biopsy under ultrasound control
  1. R J ASPINALL, Digestive Disorders Foundation Fellow
  1. ICRF Molecular Oncology Unit
  2. Imperial College School Of Medicine
  3. Hammersmith Hospital, London W12 0NN, UK
    1. S SHAH,
    2. J F MAYBERRY,
    3. A C B WICKS,
    4. Y REES,
    5. R J PLAYFORD
    1. Leicester General Hospital
    2. (approved training centre for European Accreditation in Gastroenterology)
    3. Leicester, UK Email: r.playford{at}ic.ac.uk

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      Editor,—I read the recent occasional viewpoint by Shah et al (

      ) with much interest. The authors describe their regional practice of mandatory real time ultrasound guidance for percutaneous liver biopsy in all cases of suspected diffuse liver disease. However, the published literature does not convincingly support the universal adoption of such a policy.

      The only prospective randomised study cited in support of their protocol, by Lindor and colleagues,1 is open to a number of methodological criticisms. In particular, in an unspecified proportion of the patents randomised to ultrasound guidance, the procedure was not actually performed under direct guidance and was instead immediately preceded by a “biopsy room” ultrasound scan. The net result of this may have been to selectively raise the pre-biopsy scanning rates in the “ultrasound” cohort who were already more likely to have been previously scanned than the “blind” patients (76–78% v 67–68% in the respective groups).

      In terms of the reduction in post-biopsy complications claimed by Lindor et al, the major impact was a reduction in hospitalisation due to pain. There was no statistically significant difference in the rates of bleeding or hypotension. The reduction in pain, in a non-blinded study, could have been due to several factors such as the patients' perceptions of a “safer” guided scan or the potential for the physicians to more readily hospitalise patients with abdominal pain in the “blind” group.

      There is considerable published data available regarding the safety of percutaneous liver biopsy without real time ultrasound guidance.2-4 Indeed, the British Society of Gastroenterology's recent guidelines do not advocate changing from the practice of pre-procedural ultrasound scanning (which will be part of the routine investigation of most patients with suspected hepatic disorders anyway) to biopsies performed exclusively by radiologists under imaging control5 and it is difficult to see how adopting such a policy nationally could be justified.

      Finally, I would urge that too much gravity is not placed on the cited abstract6 regarding a survey in which 75% of British gastroenterology trainees requested formal training in ultrasonography. The performance of sufficient procedures to be certified competent in this radiological procedure and to remain so throughout a lifetime of clinical practice would have enormous ramifications for the workload of gastroenterology units in this country. I personally suspect that most specialist registrars would ask for training in how to ride a unicycle if they thought it might make them more marketable to potential employers.

      References

      Reply

      Editor,—The technique used in the Lindor paper was somewhat of a hybrid between the “X marks the spot” (site usually marked in ultrasound department and the patient transferred to the ward for the procedure) and real time ultrasonography performed in the department under continuous visualisation. In their paper, Lindor and colleagues performed an ultrasound immediately before performing the procedure within the department. Using Lindor's method, the patient may move prior to biopsy, and intrahepatic vessels cannot be avoided. It is therefore an inferior technique compared with using the “real time ultrasound guided biopsy” method recommended by us. Nevertheless, the relevant statistical analyses from their study were as follows: two patients required hospitalisation in the ultrasound group compared with nine in the blind biopsy group (p=0.04), pain being the reason for admission in seven patients and pain plus hypotension in four. Bleeding occurred in nine patients in the ultrasound group versus 18 in the blind biopsy group (p=0.07). Simply stating that this last finding, which had a twofold difference between the groups was not significant and by implication not important, ignores what might be a very relevant trend, which did not reach the “magical” p<0.05 level due to insufficient numbers (that is, a type II error). As stated in our paper, a similar situation is probably relevant in the failure of studies to show significant differences in mortality due to the large numbers required.

      Clinical procedures are now the subject of appropriate monitoring. When clinicians fall below standard and imperil the safety of the patient, questions of competence are raised. The current concern about the safety of cardiac surgery has raised public awareness of the need for adequate training in all clinical procedures. The GMC and other professional bodies are looking at all aspects of day to day clinical practices and the move towards structured training of junior doctors is part of these developments. Clearly there is a need to train gastroenterologists in endoscopic techniques—the need is no less for the practice of liver biopsy. “See one, do one, teach one” is an aphorism that will not stand up in the 21st century.

      Dr Aspinal fails to mention what we consider to be one of the key results in the paper by Lindor et al; one of the patients in the blind biopsy group had to have emergency surgery for a damaged gall bladder. As stated in our paper, this situation can be virtually completely avoided by using real time ultrasonography. In the current climate, patients in whom a blind biopsy has led to perforation of the gall bladder, pleural cavity, or colon will seek legal redress for such blunders. When seeking consent, doctors must explain the details of the procedures and the safety margins associated with them. Failure to mention the added safety of using a guided rather than a blind biopsy could be seen as negligent. We hope that Dr Aspinal never faces this dilemma.

      Dr Aspinal's final paragraph, although amusing, trivialises the serious issue with which training in ultrasonography is currently causing in relationship to European accreditation in gastroenterology. Many European countries consider that a failure to be adequately trained in this technique should prevent the person from being accepted as a trained gastroenterologist. Although Dr Aspinal may not wish to venture outside the UK to practice medicine, many other clinicians do. Finally, one of the specialist registrars at our hospital did learn to ride a unicycle, it did not help his career progression but he was a very popular character.

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