Beyond counting: current evidence on the problem of retaining foreign bodies in surgery?

Retained foreign bodies (RFB) are a rare but devastating and preventable complication in surgery. Despite an increasing body of literature over the last decade, it has been difficult even to accurately estimate how frequently these events occur. An estimate based on claims data suggests the incidence is in the range of 1 in 9000 to 1 in 19000. The current approach to the prevention of RFB relies on a standardized counting protocol developed by the Association of PeriOperative Registered Nurses (AORN) and adapted in operating rooms (ORs) across the country. The counting process is labor-intensive and has been shown to negatively affect case progression and team performance. In addition, to date, there is no data regarding the accuracy or reliability of manual counting. Despite this uncertainty regarding the limitations of the current approach, new technologies are being investigated as adjuncts to the manual counting protocol. The 2 articles published in this issue of Annals of Surgery take an important step toward understanding the utility of our current approach to the prevention of RFB. The paper by Egorova et al identifies cases involving count discrepancies through the hospital reporting system at a large academic institution and its affiliates. By linking these reports to administrative data, they are able to estimate the rate of RFB as well as evaluate the ability of the counting protocol to detect RFB as they occur. Finally, they provide the first cost analysis of miscounts and compare it with another approach, performing universal radiographs in the operating room. There are several important points to highlight in this study. First, the authors report a RFB rate of 1 in 7000. Most of the previous literature on this topic has been limited to cases that were identified by review of medico-legal cases. Although this study reports a higher rate than those previously published in the literature, this is still likely an underestimate because it relies on voluntary reporting by practitioners. Beyond just reporting the rate of RFB, the authors estimate the ability of the manual counting protocol to detect and prevent these events. Most practitioners anecdotally lament the limitations of the manual count, but this is the first published estimate of its test characteristics: a sensitivity of 77% and specificity of 99%. Because of the low rate of RFB, this correlates to a low positive predictive value; only 1.6% of discrepant counts was actually associated with a RFB, leading practitioners to frequently disregard the discrepancy or rely on routine postoperative imaging for further evaluations. Disturbingly, they found that one-third of discrepant counts did not prompt an intraoperative x-ray despite this being the standard procedure at the study institution. It is important to note, as the authors point out, that these estimates do not take into account the missing items that are identified on interim counts. Previous literature reported that 88% of RFB were associated with a correct count; however, this is the first report of the likelihood of a RFB given a counting discrepancy. They report a positive likelihood ratio of 113, meaning that the odds of a retained foreign body are increased 100 times if there is a persistent discrepancy between the initial and