Evaluation of the Time-dependent Contamination of Spinal Implants: Prospective Randomized Trial

Prospective study OBJECTIVE.: To evaluate contamination in spinal implants using a liquid culture medium and the effect of covering an implant set on contamination.

Postoperative infection rates increase with the use of spinal implants. Because implant contamination may be an important origin for postoperative infections, investigation, evaluation, and taking required precautions to prevent these contaminations are critical.

Patients operated on for various spinal pathologies were randomized. The patients were divided into groups of covered and uncovered implant sets. The screw samples were placed in liquid culture medium immediately after opening the implant set. The implant set in the covered group was immediately covered with a sterile surgical towel. A new screw was taken from the implant set and cultured in the liquid culture medium every 30 minutes. At the end of 24 hours, swabs with samples from the liquid culture medium were used to culture blood agar. At the end of 48 hours, the samples with growth were considered contaminated.

Growth started after 30 minutes in the uncovered group, whereas only a single growth was noted after 60 minutes in the covered group. Contamination increased with time in both groups, but more so in the open group. A statistically significant difference in contamination was found between the groups at and after 30 minutes.

Contamination increases with time in all implant materials. Contamination rates can be reduced by using simple precautions, such as covering the implant set. Culturing the entire implant samples in liquid culture medium is accepted as a safe and more effective method in evaluating contamination.

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