# Increased chromium and molybdenum blood levels after minimally-invasive repair of pectus excavatum

## TL;DR

This study found increased chromium and molybdenum blood levels in patients after minimally-invasive pectus excavatum repair with metal bars.

## Contribution

The study provides new evidence of increased blood metal levels after MIRPE using stainless-steel bars.

## Key findings

- Chromium and molybdenum blood levels were significantly higher after bar implantation.
- Nickel and manganese levels increased but not significantly.
- No clinical symptoms of metallosis were observed in patients.

## Abstract

Minimally Invasive Repair of Pectus Excavatum (MIRPE) is the most popular technique to repair pectus excavatum in young patients. One or more metallic bars are inserted and maintained for at least 2–3 years. Only a few reports on possible metal release in these patients have been published. The study aimed to search for an increase in blood metal levels in patients after MIRPE and to investigate if surgical details (number of bars and stabilizers) were correlated with metal release.

We have prospectively studied blood levels of chromium, nickel, molybdenum and manganese before bar implant in a group of patients undergoing MIRPE between 2017 and 2019 and, in the same patients, at the moment of bar removals between 2020 and 2022. All our patients had the same stainless-steel bar. Blood samples were analysed using inductively coupled plasma mass spectrometry.

We included a total of 53 (10 females) patients. Median age at MIRPE was 15.4 years. After a median bar maintenance time of 3.1 years, we observed significantly higher mean levels of chromium (2.43 vs. 0.52 µg/L) and molybdenum (1.87 vs. 0.35 µg/L; p < 0.05). Nickel (4.24 vs. 80.80 µg/L) and manganese (12.69 vs. 19.81 µg/L) were also higher, although not statistically significant. No differences were found regarding the number of bars, stabilizers implanted or gender. No patients had clinical symptoms of metallosis.

We demonstrated that metal blood levels increase in patients with retrosternal bars after MIRPE. Clinical implications of our finding are still unknown.