Macquarie University study finds surgical instruments can remain inside patients undetected for more than 6 months

5 May 2020

When a drain tube, vascular stent or surgical pack is wrongly left in a person’s body following surgery or during post-operative care, one in six incidents is not detected for at least six-months.

New research from Macquarie University has not only identified the length of time before these items known as ‘retained surgical instruments’ remain undetected but also the main reasons why they occur.

Led by Associate Professor Peter Hibbert, from the Australian Institute of Health Innovation, Macquarie University, the research was based on analysis of 31 investigations by the Victorian Department of Health and Human Services into incidents that had occurred in hospitals and led to patients suffering serious harm.

Of all reported events in hospital that lead to a patient’s death or permanent loss of function, known as sentinel events, those caused by retained surgical instruments are the most common.

Incidents of retained surgical instruments occur in all types of surgery, but most often in abdominal operations. They can also occur during post-operative care.

The research showed that of the incidents of surgical instruments being wrongly left inside a patient, 68 per cent were surgical packs, drain tubes and vascular devices. Nearly one quarter of the incidents were detected either immediately in the post-operative period or on the day of the procedure. However, one in six were only detected after 6 months, the longest period being 18 months.

Associate Professor Hibbert explained that given the harm and distress associated with this type of incident, it was imperative to identify the number and type of events in the hospital system and the possible ways to avoid future events.

Associate Professor Hibbert said this new research not only identified the most comment means by which retained surgical instruments occurred but also demonstrated the importance of reviewing multiple events from multiple hospitals in order to determine the most likely contributing factors.

Factors that were most likely to contribute to a surgical instrument being wrongly left inside a patient after surgery include:

  • Staff not counting the number of devices used such as surgical packs (sponges) before as well as after a procedure
  • Staff fatigue and poor communication between staff
  • Staff being unfamiliar with a device or a procedure
  • Surgery that goes on for longer or is more complex than expected

Associate Professor Hibbert commended the Victorian Department of Health and Human Services for their support of this research and urges all hospitals to use the results to better understand these rare but serious and distressing events and how to prevent them.

Journal article:
Peter D Hibbert, Matthew J W Thomas, Anita Deakin, William B Runciman, Andrew Carson-Stevens, Jeffrey Braithwaite, A qualitative content analysis of retained surgical items: learning from root cause analysis investigations, International Journal for Quality in Health Care, mzaa005,

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