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Cochlear implantation in children: labyrinthitis following pneumococcal otitis media in unimplanted and implanted cat
Insights
Cochlear implantation does not increase labyrinthitis risk from pneumococcal otitis media. Grafting the round window with fascia or Gelfoam significantly reduces labyrinthitis in implanted cochleas.
Area of Science:
- Otolaryngology
- Infectious Disease
- Neurosurgery
Background:
- Pneumococcal otitis media is common in children and can cause labyrinthitis after cochlear implantation.
- Assessing this risk and preventative measures is crucial for patient safety.
Purpose of the Study:
- To evaluate the risk of labyrinthitis following pneumococcal otitis media in a cat model after cochlear implantation.
- To determine if grafting the round window membrane minimizes this risk.
Main Methods:
- A cat model of pneumococcal otitis media was used.
- Kittens underwent cochlear implantation with or without fascial or Gelfoam grafts.
- Animals were inoculated with Streptococcus pneumoniae post-implantation, and labyrinthitis incidence was assessed.
Main Results:
- Labyrinthitis occurred in 44% of controls, 50% of implanted ungrafted, and 6% of implanted grafted cochleas.
- Grafting the round window significantly reduced labyrinthitis compared to ungrafted implants.
- No significant difference in efficacy was found between fascial and Gelfoam grafts.
Conclusions:
- Cochlear implantation does not elevate the risk of labyrinthitis in the context of pneumococcal otitis media.
- Using a graft (fascia or Gelfoam) on the round window around the electrode entry point is desirable to minimize labyrinthitis risk.
Abstract:
Pneumococcal otitis media is frequent in young children and could lead to labyrinthitis post-implantation. To assess the risk, and methods of minimizing it by a graft to the round window around the electrode entry point, we have used a cat animal model of pneumococcal otitis media. Twenty-one kittens were used in the study. Thirty-two cochleas were implanted when the kittens were 2 months of age. Fourteen cochleas were implanted without using a graft (12 were available for study); 9 had a fascial graft, and 9 a Gelfoam graft (7 were available for study). The implanted kittens had their bullae inoculated with Streptococcus pneumoniae 2 months after implantation and were sacrificed 1 week later. There were also 9 unimplanted control ears which were inoculated when the animals were 4 months of age. Labyrinthitis occurred in 44% of unimplanted control, 50% of implanted ungrafted, and 6% of implanted grafted (fascia and Gelfoam) cochleas. There was no statistically significant difference between the unimplanted control and the implanted cochleas (p < 0.05). There was, however, a difference between the implanted-ungrafted and implanted grafted cochleas, but not between the use of fascia and Gelfoam to graft the round window entry point. As a result, the data indicates that cochlear implantation does not increase the risk of labyrinthitis following pneumococcal otitis media, but it is desirable to use fascia as a graft to the round window around the electrode entry point.