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Otitis media with effusion (OME) is a common disorder in children, and insertion of ventilation tubes for effusion persisting for more than 3 months is well accepted. Although this is a minor procedure, the major disadvantage is the need for general anesthesia in the majority of children and furthermore, ventilation tubes have their known additional side effects [1]. A myringotomy, created with a CO₂-flashscanner, has proven to be a safe alternative to ventilate the middle ear [2, 3]. However, evidence is lacking that laser myringotomy is a better method than ventilation tubes in the treatment of otitis media with effusion. This study was designed to answer the following questions. What is the effectiveness of laser myringotomy versus the ventilation tube in children with chronic otitis media with effusion? And, how can we create a model to estimate the outcome of laser myringotomy for these patients, taking into account known factors of influence on the development and course of otitis media with effusion [4]?

In seven Dutch hospitals, all children presented with otitis media with effusion were enrolled in the study. Effusion was classified as middle ear effusion of any colour but without fever, otalgia, or otorrhea, and was diagnosed by an otolaryngologist with binocular otoscopy in combination with tympanometry and/or pure tone audiometry. Inclusion criteria were children until 11 years of age with bilateral effusion and hearing loss for more than 3 months. Exclusion criteria were all otoscopic disorders leading to asymmetry between both ears.

To compare laser myringotomy with the ventilation tube, and to exclude confounding factors, both interventions were performed in one patient, during one procedure, and under general anesthesia. In one ear, a ventilation tube was inserted using cold knife myringotomy, and in the other ear laser myringotomy was performed with a CO₂-laser. The laser power setting varied from 7 to 20 W, and the laser diameter from 1.8 to 2.6 mm (2.6 mm in 76.4%). Adenoidectomy was performed according to the known guidelines for indication [5]. No antibiotics or ear drops were given before, during, or immediately after the operation and on the laser side, effusion was not aspirated.

Follow-up was scheduled every month for 6 months but 90 children were scheduled each week to determine the average closure time of the laser perforation.

Assignment of the side for laser myringotomy or tube insertion was made randomly. Success was defined as the absence of effusion or otorrhea. A logistic regression model was used with success of the therapy as a binary outcome. Repeated measurements of this outcome variable were available within a single patient, generated by the two differently treated ears observed at the control visits. Furthermore, between-patient co-variables were included in the model to explore their modifying role on the treatment effect.

Two hundred eight children (out of 1403) with signs and symptoms of otitis media agreed to participate and finally received the trial intervention (Fig. 1). The time interval between indication and operation was on average 4.6 weeks (S.D. 3.8). The mean closure time of the laser perforation was 2.4 weeks (range 0.9–5.6) and the meantime the tube was extruded or not functional was 4.0 months (range 0.4–7.9, median 4.2). The tube showed a better outcome than the laser perforation (Fig. 2). Adenoidectomy performed as a combined procedure, and older age both had a positive significant influence on the success rate of both procedures (p=0.006, p=0.01). A significant negative influence was found in patients with one or more siblings (p=0.03), parental smoking (p=0.01), school admittance (p<0.001), and a parent's history of otitis media (p=0.006). No significant correlation was found for history of tubes, time of hearing loss, gender, ethnic origin, history of adenoidectomy or adenotonsillectomy, season, breast-feeding, cleft palate, and tonsillectomy performed as a combined procedure. At follow-up, otorrhea occurred more frequently at the tube side than at the laser side.

One patient suffered from otalgia the first 2 days after laser myringotomy, and that was treated with oral analgesics. In one laser-treated ear, an epidermal pearl of the eardrum was noticed that could be removed by suction in the office setting.

After modelling with backwards elimination, 10 of 17 recorded co-variables were accepted to create a logistic regression model to explore their modifying role for laser treatment and insertion of a ventilation tube after 6 months using the formula:

(Table 1)

Our study confirms that laser myringotomy is a safe method to treat chronic otitis media with effusion in children [6, 7, 8]. However, laser myringotomy is less effective than a ventilation tube in the treatment of this disorder. The difference in success between laser and tube can only be explained by the difference in duration of ventilation of the middle ear because known risk factors for otitis media were not confounding in this study as the patient was his own control.

The success rate for laser in this trial, of approximately 40% (range 46.6–35.5%) was reached in the first month after the procedure and stayed fairly constant, whereas the success rate for the ventilation tube showed a significant decrease from 87.4% after 1 month to 70.7% at 6 months (range 87.468.5%). The effect of the laser myringotomy can therefore be established 1 month after the procedure.

The higher success rate of laser myringotomy reported by other authors (4683%) could be ascribed to selection bias since none of these studies were controlled randomised trials, or to the use of ear drops or oral antibiotics [9, 10, 11, 12].

In comparing baseline variables and risk factors for otitis media between participating and eligible nonparticipating patients, we found a high external validity. Adenoidectomy identified in several studies as a positive treatment outcome variable for otitis media with effusion [5, 13] was also a significant factor in our study. Season and hearing loss, however, were not found to correlate with outcome but were also implied in our logistic regression model as a result of positive findings reported in literature [14, 15, 16]. The model can be applied to the individual child to explore the modifying role of co-variables on the treatment effect of laser myringotomy or placement of ventilation tubes.

Outpatient laser myringotomy has become a new treatment modality in the surgical therapy for otitis media with effusion. The higher recurrence rate of effusion after laser myringotomy has to be weighed against the alternative of greater success for the ventilation tube, carrying, however, the need for general anesthesia, known side effects on the tympanic membrane [1], and higher costs [7]. For children with chronic otitis media with effusion, the presented logistic regression model facilitates the otolaryngologist to choose between these two surgical methods.