Radiological Findings of Incidental Retained Broken Needle Fragment in the IVDU Population and its Potential Clinical Implication

Purpose: Retained broken needles (RBNs) in patients is a potentially underreported complication of intravenous drug use (IVDU) with marked clinical variability. Aside from the well-documented complications of IVDU, RBNs can increase the risk of injection site infection and needlestick injury. In some cases, RBNs are found incidentally in asymptomatic patients. Identification of RBNs poses a challenge for radiologists due to small size, superimposition, plane of section imaging considerations, and a lack of familiarity with RBNs appearance. This study aims to assess the radiological findings of RBNs in the IVDU population and their potential clinical management.

Methods/Materials: This study included all patients with a history of IVDU who presented to the Temple University Hospital with RBNs in 2021. Presence of RBNs was confirmed via imaging. Data collected on the study population included RBN location and size, complications, blood culture results, and imaging modality. Cases of incidental findings were investigated and classified as the presence of a RBN without prior knowledge of a retained needle.

Results: 71 patients in the IVDU population with radiographically discovered RBNs were identified. RBNs were most observed in the foot (31.0%), forearm/elbow (19.7%), neck (16.9%), and upper arm (9.86%). Fifty-nine patients (83.1%) with RBNs were found to be incidental. Radiography located needle fragments (56.3%) slightly more often than CT (43.6%). Around half (50.7%) of all patients presented with positive blood cultures. Staphylococcus was most prevalent (66.7%) with MRSA representing 18.3% of all patients with positive cultures. Two patients demonstrated RBN emboli to the lung (2.82%).

Conclusions: This study suggests that patients with IVDU-RBNs are commonly found incidentally. These patients are likely at an increased risk for infectious complications when compared to published rates in the non-RBN IVDU population, particularly MRSA. As such, prompt radiologic identification of RBNs may be imperative as IVDU-RBN patients may require a different antibiotic course. Greater awareness of RBNs and the ability to employ post-processing imaging techniques may prove advantageous in identifying occult RBNs.