Performing a mastoidectomy, a group of operations on the temporal bone and middle ear to drain, expose, or remove an infectious, inflammatory, or neoplastic lesion, during cochlear implantation for young children does not decrease the possibility that the young patient will develop a middle ear infection. This is the conclusion of a new research study out of Israel.
Acute otitis media (AOM), or middle ear infection, has emerged as being a very common complication of cochlear implantation, especially in children under age two. An ear infection at first glance may appear to be a minor post-implantation complication, but the threat of otitis media is nevertheless very worrisome for the patients and their families. Their concern is that acute otitis media in implanted patients can be complicated by meningitis more often than in the non-implanted population.
One consequence of acute middle ear infection is mastoiditis, which occurs when the infection of the ear spreads from the ear to the mastoid bone of the skull (anatomically located directly behind the ear). The mastoid bone fills with infected materials and its honeycomb-like structure may deteriorate. Before the advent of antibiotics, mastoiditis was one of the leading causes of death in children. Now mastoiditis is a relatively uncommon complication of middle ear infection. However, past research has shown an increased incidence in mastoiditis among implanted children and adults who develop middle ear infections.
Some 350 patients have undergone cochlear implantation at a major Israeli treatment facility between 1989 and 2003. Pediatric implantations were carried out from 1993. Acute otitis media and mastoiditis complicated the post-operative course only in children. Specialists at the facility set out to determine the incidence of post-implantation acute infection of middle ear and mastoid only in pediatric patients.
This is the first investigation that evaluates the rate of acute otitis media in children implanted with different surgical approaches, one with and one without mastoidectomy. The authors of “Acute Otitis Media and Mastoiditis Following Cochlear Implantation: Comparison of Two Surgical Approaches,” are Lela Migirov MD, Arkadi Yakirevitch MD, and Jona Kronenberg MD, from the Department of Otolaryngology and Head and Neck Surgery, Sheba Medical Center (affiliated to the Sackler Faculty of Medicine), Tel Aviv University, Tel Aviv, Israel. Their findings are being presented at the American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting & OTO EXPO, being held September 19-22, 2004, at the Jacob K. Javits Convention Center, New York City, NY.
Methodology:
A comparative retrospective study was conducted on all the children up to 16 years of age at the time of implantation who underwent cochlear implantation between 1993 and 2003 and were followed up for at least 18 months. The children were divided into two groups according to the surgical technique that had been used for the implantation: the Posterior tympanotomy approach (MPTA-with mastoidectomy) group and the Suprameatal approach (SMA-without mastoidectomy) group.
The SMA is based on the retroauricular tympanotomy technique. The middle ear is entered through the external auditory canal. The wide exposure of the promontory enables safe and easy performing of cochleostomy. The electrodes are passed into the cochleostomy through the closed suprameatal tunnel drilled within the temporal bone, postero-superior to the external auditory canal, posteriorly to the chorda tympani and lateral to the body of the incus. The selection of the SMA ran counter to the traditional MPTA cochlear implantation procedure, used primarily between 1993 until 1999.
The patients’ medical records were reviewed for age at the time of implantation, gender, a history of pre- and post-implantation acute otitis media, or mastoiditis, the surgical approach used, and history of adenoidectomy or insertion of ventilating tubes prior to implantation. The incidence of middle ear infection and mastoiditis before and after the implantation was compared between the two groups.
Results:
The study cohort consisted of 234 children, aged between 11 months and 16 years. Of these children, 116 (68 boys and 48 girls) underwent the implantation with the MPTA and the remaining 118 children (77 boys and 41 girls) were operated on with the SMA. The postoperative follow-up time was at least 18 months in both groups. Children in SMA group were significantly younger. Key findings include: