Age Important but Not Key to a Positive Outcome for Perforated Ear Drum Surgery

As any parent knows, a perforated eardrum can be serious. Damage to the tympanic membrane can affect the transmission of sound from the outer ear to the three connected bones in the middle ear (the malleus, incus, and stapes), leading to hearing loss. The most common cause of a perforated eardrum is poor function of the Eustachian tube, which connects the middle ear to the back of the nose, leading to negative middle ear pressure. Other reasons for this condition include a severe or untreated infection that can break your child's eardrum and flood the ear canal. Eardrum perforations may lead to hearing loss and repeated ear infections. In very rare cases, untreated ear infections can lead to mastoiditis (an infection of the skull behind the ear), meningitis, or brain abscesses.

The potential for hearing loss makes the debate regarding tympanoplasty, the reconstruction of the tympanic membrane, important. The procedure generally involves repairing the tympanic membrane (ear drum); the most prevalent form of this surgery is called the Wullstein or Type 1, used when the ossicular chain is intact. The issues surrounding this procedure are:

* Wide disparity in the reported results of tympanoplasty in children, with reported surgical success rates ranging from as low as 35 percent to as high as 94 percent.* Optimum timing of the surgery is controversial, with some authors reporting reduced success rates in younger children, and others reporting equally good results in children of all ages. * The site and size of the perforation, the status of the perforation ("wet" or "dry"), the status of the healthy ear, the surgical technique, the skill of the surgeon, and history of previous adenoidectomy.

A considerable difference of opinion exists among ear, nose, and throat specialists regarding the minimum age for a child to be considered for tympanoplasty and the reasons other than age for not performing a tympanoplasty in a child.

Another variable in the debate is the increased use of ventilation tubes for treatment of childhood otitis media with effusion (OME). A substantial number of tympanic membrane perforations in children have been attributed to the use of ventilation tubes; the repair of such tympanic membrane perforations may present some difficulty in cases where the perforation closely approaches the anterior annulus, leaving only a very narrow rim of residual tympanic membrane. The difficulty posed by the narrow anterior rim is well acknowledged; little data exists regarding the impact this has on the surgical success rate in children.

A study was undertaken in an Irish treatment center to examine the outcome of tympanoplasty in children and investigate the influence of the age of the child, the site and size of the perforation, history of ventilation tube insertion, and presence of a narrow anterior rim of tympanic membrane on the surgical result. The authors of "Factors Influencing Outcome of Tympanoplasty in Children" are Patrick Sheahan MB AFRCS, Tadhg P O'Dwyer MB FRCSI FRCS, and Alexander W Blayney MCh FRCSI FRCS, are all from the Department of Otolarygology, The Children's Hospital, Dublin, Ireland. Their findings are to be presented September 24, 2002, at the American Academy of Otolaryngology--Head and Neck Surgery Foundation Annual Meeting and OTO EXPO, September 22-25, 2002, at the San Diego Convention Center, San Diego, CA.

Methodology: Fifty-four children undergoing 62 consecutive type 1 tympanoplasties at the Children's Hospital, Temple Street, Dublin, between 1996 and 2000 were reviewed. Only cases of primary surgery for repair of central tympanic membrane perforations without evidence of cholesteatoma or ossicular erosion were included; excluded were cases involving repair of marginal perforations or retraction pockets, mastoidectomy, or revision surgery. Ears were operated on utilizing either a behind the ear (28 cases) or in front of the ear incision through the external auditory canal to permit middle ear surgery (34 cases).

Children were followed up for a mean of one year after their surgery with successful surgery being defined as the presence of an intact graft at most recent follow-up. The review incorporated information regarding the children's age, previous history of recurrent ear infections from ventilation tubes insertion, type of perforation, presence of a narrow anterior rim, type of surgery performed, and outcome of surgery. Statistical analysis was performed using a Pearson chi-squared test or a Fisher exact test.

Results: Tympanoplasty was successful in 48 ears (77.5 percent), and unsuccessful in 14 ears (22.5 percent), including one case in which a cholesteatoma developed which required a modified radical mastoidectomy to be performed 17 months after the initial surgery. An analysis of factors thought to affect surgery outcome found:

Age: Surgery was successful in 20 of 28 children aged ten years or younger (71.5 percent), and in 28 of the 34 children aged 11 years old or older (82.5 percent). There was no statistical difference between the two groups. However, only six of the 11 operations performed on patients aged 9 or younger were successful (54.5 percent), whereas 42 of the 51 operations performed on patients 10 or older were successful (82 percent).

History of ventilation tube insertion: 39 ears had previously undergone ventilation tube insertion and surgery was successful in 30 of these cases (77 percent). Surgery was successful in 18 of the 23 cases with no history of tube insertion (78 percent). The difference between these two groups was not statistically significant.

Type of perforation: Graft failure occurred in five of the 30 ears with anterior perforations (17 percent); two of the 13 ears with posterior perforations (15 percent), and seven of the 19 ears with subtotal perforations (37 percent). More failures occurred in ears with subtotal perforations, however this was not statistically significant.

Presence of narrow anterior rim: Surgery was successful in 11 of the 18 ears with narrow anterior rims (61 percent) and unsuccessful in seven (39 percent). Ears with narrow anterior rims were significantly more likely to be unsuccessful than ears without narrow anterior rims.

Conclusion: The findings suggest that tympanoplasty may be performed on children over the age of nine years with a reasonable likelihood of surgical success. On the other hand, younger children may have a reduced success rate; accordingly they should be carefully selected for surgery. Perforations with narrow anterior rims of residual tympanic membrane also have a reduced short-term success rate; however, site and size of perforation, and history of ventilation tube insertion, had no significant impact on outcome. This study focused on the importance of careful selection of candidates for tympanoplasty among younger children. Finally, the results highlight the importance of the status of the anterior rim of the perforation, rather than its site or overall size, in determining the likelihood of success.

Visit http://www.entnet.org/healthinfo/ears/perforation.cfm for more information on the diagnosis and treatment of perforated eardrums.