In the operating room, surgical needles are small but essential tools — yet when one goes missing, even the tiniest needle can create serious risks. Retained needles can cause pain, infection, tissue injury, or the need for additional surgery. Beyond these physical dangers, they carry medicolegal implications and can undermine trust between patients and surgical teams.
While imaging — particularly X-rays — is often used to locate missing needles, studies show that plain radiographs are surprisingly unreliable for detecting these tiny objects. A “clear” X-ray is not always reassuring.
The Patient Risks of a Missed Needle
Even a tiny retained needle can have severe consequences:
- Infection and inflammation: Needles act as foreign bodies. They may trigger localized inflammation or serve as a nidus for infection, sometimes leading to abscesses.
- Pain and tissue injury: Depending on location, a needle can puncture organs, vessels, or nerves, causing chronic pain or neurological symptoms.
- Surgical re-intervention: Removing a retained needle often requires a second procedure, ranging from minimally invasive retrieval to a full surgical exploration.
- Delayed diagnosis: Needles may remain undetected for weeks, months, or even years, occasionally discovered only after complications develop.
Contegiacomo et al. (2020) document several such cases, where patients experienced post-operative complications because a small needle went unnoticed. (PMC link)
Why X-Rays Often Miss Needles
Despite being the default imaging modality, X-rays frequently fail to detect retained needles:
- Needle size: Needles smaller than a few millimeters produce faint or barely visible images. Even experienced radiologists can overlook them.
- Orientation and tissue overlap: A needle lying parallel to the X-ray beam, embedded in dense tissue, or hidden beneath other instruments may not appear on a radiograph.
- Evidence from studies:
- In ophthalmologic cases, Kieval et al. (2009) found plain radiographs had only ~54% sensitivity for tiny suture needles. (PubMed link)
- Susmallian et al. (2025) reviewed 145 surgical missed-item events and reported a sensitivity of just ~30% for X-rays detecting needles — meaning seven out of ten retained needles went unnoticed on imaging. (PubMed link)
These findings show that while X-rays can confirm a needle if seen, a negative result is far from definitive.
Quick Fact: X-Rays Miss Most Tiny Needles
“Studies show that plain radiographs detect only 30–54% of retained surgical needles. This means that in many cases, a ‘clear’ X-ray does not guarantee patient safety.” — Susmallian et al., 2025; Kieval et al., 2009
Why it matters:
- Small needles (<13–17 mm) are often invisible on X-ray.
- Orientation, tissue density, and overlying anatomy can hide needles from even experienced radiologists.
- Reliance on imaging alone can lead to pain, infection, or additional surgery for the patient.
Takeaway for OR Teams:
- Treat a negative X-ray as suggestive, not definitive.
- Count, inspect, and communicate — imaging is only one piece of the safety puzzle.
Real-World Impact
The consequences of relying on X-ray alone can be serious. Weprin et al. (2021) emphasize that detection rates drop sharply for needles smaller than 17 mm, and are nearly impossible for needles under 13 mm. (PMC link)
In practice, this means small needles are often invisible on standard radiographs, even when surgical teams follow protocols and the X-ray is reviewed carefully. The implication for the OR is clear: a “negative” radiograph should never replace meticulous counting, site inspection, or team communication. Even tiny needles can lead to patient harm if they are not detected.
Why Awareness Matters in the OR
Recognizing the clinical consequences of retained needles and the limitations of X-rays reinforces why vigilance is non-negotiable:
- Counting remains critical. Imaging should augment, not replace, visual and manual inspection.
- Effective communication with radiologists improves the chance that a missing needle will be flagged if it appears on an X-ray.
- Teams should maintain heightened awareness, particularly in procedures with very small needles, complex anatomy, or minimally invasive approaches.
Conclusion
Retained surgical needles are deceptively small but potentially harmful. The literature shows that X-rays often fail to detect these needles, especially when they are tiny or poorly positioned. Patients face risks ranging from pain and infection to additional surgery, highlighting that detection is not just a technical challenge — it is a matter of patient safety.
For surgical teams and OR directors, the lesson is clear: do not rely solely on imaging. Counting protocols, careful inspection, and communication are essential safeguards. Understanding the limitations of X-ray is critical — because a “clear” scan does not always mean the patient is safe.
References
- Contegiacomo A., et al. “Radiological features and management of retained needles.” BMJ Case Reports. 2020. PMC link
- Weprin S., et al. “Risk factors and preventive strategies for unintentionally retained surgical sharps.” Patient Safety in Surgery. 2021. PMC link
- Susmallian S., et al. “Assessing the diagnostic value of radiographs for retained surgical items: a cautionary analysis.” Br J Radiol. 2025. PubMed link
- Kieval JZ, et al. “Efficacy of portable X-ray in identifying retained suture needles in ophthalmologic cases.” Eye (Lond). 2009. PubMed link
