Short summary

Cochlear implantation is done by operating a device with an electrode inside the inner ear, so the patients can gain their hearing back. This procedure is not without risks of postoperative infection. We aim to investigate the postoperative infection rate between patients receiving prophylactic postoperative antibiotics, and patients who does not recieve this. This will be a retrospective cohort study of approximally 900 patients, from 2010 to 2022.

Rationale

Cochlear implantation (CI) is widely regarded as a safe and effective procedure for patients with deafness or severe hearing loss. In 2019 there were performed 736.000 surgeries worldwide. However, the CI-procedure is not without risks of complications, such as infection, dizziness, loss of residual hearing and postoperative bleeding. It is therefore essential to gain knowledge related to the complications which can occur after CI. Severe infections can lead to device removal, but also endanger patient's life's by spreading to the brain or meninges. In patients undergoing CI, the risk of post-operative wound complications, is up to 22%, usually of less serious nature. Staphylococcus aureus and pseudomonas aeruginosa have been found to be frequent sources to infection and are both capable of biofilm formation. Currently there is little consensus regarding postoperative antibiotic prophylactic treatment and its effect on the postoperative infection rate after CI. In a systematic review from 2016 by Anne S et al, the authors concluded that the studies on antibiotic prophylactics after CI could not provide sufficient evidence concerning the benefits of postoperative antibiotic treatment. In a study from 2018 by Almosnino G et al, the authors found no significant difference in postoperative infectious outcome between patients receiving, or not receiving postoperative antibiotics. However, the population size and the follow-up time in the Almosnino G et al study was limited. In addition, symptoms of infection can occur a long time after implantation, because of the biofilm properties that allow bacteria to survive, by sheltering and communicating. Formation of more bacteria can then occur without disturbance, protected from the organism's immune system. In a study from 2019, by Sayed-Hassan et al, the authors found the rate of major infections, was lower for patients who received prolonged antibiotic treatment after CI up against prophylactic antibiotic treatment (one single-dose after surgery). Especially in children where the difference was 3.2% infection rate for prophylactic antibiotics vs 1.2% with prolonged antibiotic treatment. For adults the difference was 0.8% infection rate for prophylactic antibiotics vs 0% with prolonged antibiotic treatment.

We aim to assess the impact of postoperative antibiotic treatment on post-operative infection rate, and thereby discuss if postoperative antibiotic treatment has any benefits in the preventing treatment against infectious complication. As secondary outcomes we will calculate the overall infection rate through the years of the study and compare the infection severity, additional use of antibiotics, device removal rate, time to infection and admission to the oto-rhino-laryngology (ORL) department of Odense University Hospital (OUH).

Description of the cohort

All patients who underwent a cochlear implantation surgery procedure from january 1st 2010 to december 31st 2022, in the department of oto-rhino-laryngology at Odense University hospital. There will be no exclusion criteria.

Data and biological material

Age, birthday, BMI, age at surgery point, ASA score, hearingloss ehtiology, implant producer, implant model, surgical technique, surgeon experience, preoperative scanning results, previous local surgery, pneumococcus vaccination, side of surgery, peroperative complications, time under surgery, peroperative antibiotics, postoperative admission time, post operative antibiotic use, infection needing antibiotic treatment, infection needing surgical intervention, infection severity, recurrent infections, preoperative antibiotic, admission caused by infection, pain in surgery sight, postoperative device removal, agent of infection, time to infection, number og times on antibiotics, etc.