Laser-assisted myringotomy for otitis media: A feasibility study with short-term followup.

Abstract

Intermediate-duration middle ear ventilation appears to be a good treatment option for selected children with otitis media. Laser-assisted myringotomy is one way to provide such ventilation. It can provide prompt pain relief and resolution of middle ear effusion and effusion-related hearing loss, and it can provide an opportunity for surveillance of antibiotic-resistant organisms. We performed laser-assisted myringotomy on 97 ears of 54 children over a 5-month period. All children had acute or recurrent otitis media or persistent middle ear effusions. Our experience suggests that laser-assisted myringotomy is a feasible treatment option for selected patients. Practitioner experience and patient and family considerations will contribute to the decision whether to use general or topical anesthesia.

Introduction

Otitis media comprises several complex and overlapping entities. Infectious, mechanical, environmental, and host factors all contribute to disease. As a result, no single treatment strategy is successful for all patients. In fact, for some children, none of the common management options-antibiotics, myringotomy with tube placement, or watchful waiting-is ideal. This dilemma provided us with the motivation to experiment with a new treatment modality: laser-assisted myringotomy.

Laser-assisted myringotomy involves the use of a [CO.sub.2] laser beam and flash-scanner technology to vaporize a round opening in the tympanic membrane. This procedure can be performed with topical anesthesia in an office setting. It can provide immediate pain relief and middle ear ventilation of intermediate duration (2-4 wk). It is possible that this temporary middle ear ventilation- which lasts longer than that provided by myringotomy alone but not as long as that provided by myringotomy with tube placement-is the best strategy for some children.

In this article, we report the preliminary results of our study of the feasibility of laser-assisted myringotomy. We also discuss factors that affect the efficacy of the procedure, such as technical and anesthetic considerations, and we analyze the results of our short-term followup.

Materials and methods

We suggested the use of laser-assisted myringotomy to the parents of children with acute otitis media or otitis media with effusion who had painful ears and/or who wished to avoid general anesthesia. We defined acute otitis media as a middle ear infection accompanied by erythematous, bulging, white, or transudative tympanic membranes, otalgia, and/or fever. Children were considered to have otitis media with effusion if they had middle ear effusions of any color, but no fever or severe otalgia. Some children had both acute otitis media and otitis media with effusion. Informed consent was obtained from all participating families.

Initially, we performed laser-assisted myringotomy only on those children who were receiving a ventilation tube and only under general anesthesia. But as we became more experienced with the procedure, we also began to use it as an outpatient office procedure under local anesthesia, with or without tube placement.

We performed laser-assisted myringotomy on 97 ears in 54 children, 29 of whom received general anesthesia and 26 of whom received local anesthesia (one child received topical anesthesia in one ear and general anesthesia in the other). One child who underwent local anesthesia was given sedation.

The technique involves vaporizing a round fenestration in the tympanic membrane with a flash-scanner [CO.sub.2] laser (ESC/Sharplan; Bothell, Wash.). We positioned the laser with a helium/neon circular aiming beam, which allowed us to focus at a precise depth of field. We adjusted the power settings to the anticipated thickness of the tympanic membrane. Meticulous cleaning of the ear canal was necessary. A good knowledge of ear canal and tympanic membrane landmarks and structure is required for this procedure, as is the ability to make judgments while viewing a limited image of the tympanic membrane on a monitor rather than by direct visualization.

For data analysis, we recorded information on the indications for each procedure, the size of the laser spot, the amount of power and the number of pulses necessary, the type of anesthesia, and comments by the surgeons.

We performed a followup evaluation on each patient 2 weeks after surgery to assess tube or myringotomy patency, otorrhea, recurrence of effusion, and other data. Subsequent followup was individualized.

Results

Laser-assisted myringotomy was successful in 49 children (91%) and 91 ears (94%). In patients who received general anesthesia, the laser spot size ranged from 1.4 to 2.2 mm, and the power settings ranged from 7 to 13 W. In those who received local anesthesia, the spot size ranged from 1.8 to 2.4 mm, and power settings ranged from 10 to 22 W. Spot sizes of 1.6 to 1.8 mm were optimal for ventilation tube placement. Larger spot sizes were used to prolong the duration of the opening when drainage and ventilation without tube placement were desired.

Thick or inflamed tympanic membranes required higher power settings and/or multiple pulses. Ten of the 29 children who received general anesthesia and 11 of the 26 who received topical anesthesia required more than one laser pulse (range: 1 to 10; typically 2). Power settings were adjusted on an individual basis in an effort to penetrate the tympanic membrane with the first pulse without affecting the promontory. As we gained more experience with this procedure, we were able to selectively use higher power settings for thickened tympanic membranes. Our ability to predict the appropriate power setting, based on the physical appearance and anticipated thickness of the tympanic membrane, improved over time.

Once the myringotomy was completed, tube placement was facilitated by the lack of bleeding and the presence of a favorably shaped opening.

The procedure was most difficult to accomplish in acutely inflamed tympanic membranes, possibly because the membrane is not as flat in relation to the laser equipment. The laser has a very limited depth of field for tissue ablation. In some acutely inflamed membranes, the initial laser pulses would ablate only the membrane surface, which resulted in a small amount of bleeding. In these cases, suctioning and additional pulses were required to create an adequate opening. Possible explanations for this phenomenon include difficulty in keeping the entire laser fenestration site within a precise depth of field when the tympanic membrane was bulging and the increased thickness of an acutely inflamed membrane.

Myringotomy could not be accomplished in five children. One child's ear canals were too narrow for the specula. Another child (one ear) had an adverse reaction to topical tetracaine; he experienced immediate otalgia, dizziness, and ipsilateral facial nerve paresis, all of which resolved within 24 hours. In retrospect, we recognized that this patient had had a microperforation of the tympanic membrane. Tympanic membrane penetration was not achieved in the other three children (three ears). One child (general anesthesia; spot size: 1.6 mm) received two pulses at 9 W and two pulses at 10 W, but they were insufficient to penetrate a very thick tympanic membrane. One child (topical anesthesia; spot size: 2 mm) received one pulse at 10 W, but it did not penetrate the tympanic membrane. The third child (general anesthesia; spot size: 1.8 mm) received one 13-W pulse that did not penetrate the tympanic membrane.

In some children, the middle ear fluid welled up through the myringotomy. In others, the fluid remained in the middle ear space, but it had a "scooped out" gelatinous appearance.

The topical anesthetic seemed to be effective in most of the children, as judged by a steady state of comfort or discomfort even when the tympanic membrane was touched. Some children found manipulation of the ear canal with the speculum to be uncomfortable, even when adequate anesthesia of the tympanic membrane was achieved. The discomfort was alleviated somewhat by using smaller specula. For some children, the noise of the laser and/or the suction was distressing. But most children did not continue to express discomfort after the procedure had been completed.

Topical anesthesia was considered by the surgeon to be inadequate in three of the 26 children. Several others experienced temporary discomfort or found the entire process stressful to varying degrees. However parents were generally pleased and satisfied with the procedure, particularly when it was performed to relieve pain.

Discussion

The decrease in the incidence of mastoiditis and other complications of otitis media over the past half-century is probably attributable to antibiotics [1] and middle ear ventilation tubes. Yet despite the advances in the management of otitis media, there are many children for whom none of the currently available treatment modalities seems to be ideal. Laser-assisted myringotomy might prove to be a useful alternative.

Alternative to antibiotics. The success rate of antibiotic therapy for acute otitis media and otitis with effusion is statistically significant but modest. About one in seven children (14%) improves on antibiotics. [2,3] The types of complications of antibiotics range in severity from nuisance to life-threatening. The most common adverse effects are gastrointestinal. [4] Dermatologic reactions occur in 3 to 5% of cases [4] and might preclude the future use of that particular class of antibiotics for that child. Rare complications include severe anaphylactic, hematologic, cardiovascular, central nervous system, endocrine, renal, hepatic, and respiratory effects. [4]

Moreover, antibiotic resistance continues to be worrisome. According to the Centers for Disease Control and Prevention (CDC), Streptococcus pneumoniae is the most important cause of acute otitis media, but these organisms have become resistant to several drugs, which complicates empiric treatment decisions and results in treatment failures. [5] The prevalence of penicillin-nonsusceptible S pneumoniae is substantially higher in children than in adults, especially children in day care and those who have received previous antibiotic therapy within the preceding 1 to 3 months. [5] Local surveillance data for pneumococcal resistance that are relevant to the clinical management of acute otitis media are not available from most areas in the United States. [5] Although some state health departments consider drug-resistant S pneumoniae to be reportable, most of their reported isolates are from sterile sites rather than from middle ear fluid, and many of these isolates are from adults. As a result, systematic bias in reported information remains a concern. [5] Children with acute otitis media, particularly those who undergo myringotomy and tube placement, would be a more appropriate sampling group than the selected groups that are sometimes reported.

For children who have experienced clinical treatment failures, the CDC suggests performing tympanocentesis to determine the antibiotic susceptibility of the etiologic agent. Clinical treatment failure is defined as a lack of improvement in clinical signs and symptoms (e.g., pain, fever, and tympanic membrane findings of redness, bulging, or otorrhea) after 3 days of therapy. Obtaining a culture is particularly important in children who have recently received multiple courses of antimicrobial therapy and who are therefore more likely to harbor a multiply resistant strain. [5] Laser-assisted myringotomy provides an opportunity to obtain cultures of middle ear effusions in acutely ill children. In our study, we identified two patients with drug-resistant S pneumoniae.

Even when antibiotics are successful in resolving otitis media, they do not usually alleviate discomfort promptly. Tympanocentesis can provide some pain relief, but the opening typically lasts only hours to days. Moreover, tympanocentesis does not hasten the resolution of otitis media with effusion, [6] and it is not usually performed for acute otitis media except in neonates and in children who are at increased risk of complications of otitis media. Laser-assisted myringotomy might provide both prompt pain relief and a tympanic membrane opening that remains patent long enough to be of therapeutic value.

Alternative to tube placement. Many children who fail medical management of otitis media undergo myringotomy and tube placement, usually under general anesthesia. Middle ear ventilation tubes are helpful for many of these children, but some develop otorrhea and some have residual tympanic membrane perforations. Also, ventilation tubes can continue to function longer than is desired.

Another potential application of laser-assisted myringotomy is for the treatment of episodes of acute otitis media or otitis media with effusion during the spring. Statistically, children have fewer episodes of otitis media during the summer. It might be reasonable to offer laser-assisted myringotomy in the spring. Because the incidence of upper respiratory tract infections declines as spring emerges, some children might not need the longer-duration middle ear ventilation provided by ventilation tube placement. Protection from water, which is sometimes recommended for children with ventilation tubes, might not be necessary, and children would be free to swim during the summer.

Alternative to watchful waiting. Because some episodes of otitis media resolve spontaneously, and because of the possibility of treatment failure or complications, watchful waiting is advocated for some children. Rosenfeld estimated that watchful waiting will "cure" about 70 to 90% of acute episodes and 15 to 30% of episodes of otitis with effusion. [2] Choosing a watchful-waiting approach requires careful consideration of the risks and potential benefits of not treating as well as the natural history of the underlying disease. Left untreated, the potential complications of otitis media include otalgia, hearing loss, otorrhea, balance and coordination disturbance, acute coalescent mastoiditis, chronic mastoiditis, tympanic membrane perforation, cholesteatoma, ossicular erosion, facial nerve paralysis, meningitis, labyrinthitis, focal otitic encephalitis, lateral sinus thrombophlebitis, otitic hydrocephalus, periauricular subperiosteal abscess, Bezold's abscess, and epidural, subdural, and brain abscess. [7-1 3]

Untreated otitis media can also cause adverse developmental sequelae, including speech and language deficits, cognitive difficulties, impaired academic performance, and behavioral problems. [14-18] Children with otitis media with effusion usually have a mild-to-moderate conductive hearing loss, which can hamper the development of increasingly important communications skills. [9,8] Developmental deficits can persist even after auditory acuity has been restored. [17] Frequent otitis media with effusion during infancy has a detrimental effect on intellectual potential that is of greater magnitude in children whose potential is greatest.[14] Illness-induced communication disorders can contribute to lost employment opportunities and hamper social function. [14]

Potential of laser myringotomy. It might be possible to improve some of the technical aspects of laser-assisted myringotomy. Aspirating middle ear effusions is noisy and uncomfortable for some patients. Although some middle ear effusions are extremely thick and viscous, there is evidence that effusions might resolve without suctioning once the middle ear pressure is equalized with atmospheric pressure. [19]

In addition, some children might benefit from sedation. Nothing-by-mouth instructions could be issued to children who undergo a scheduled procedure for otitis media with effusion, but this, of course, would be more difficult to accomplish for those seeking acute treatment.

The generally positive reaction of parents whose children received topical anesthesia was encouraging. However, this might have been, at least in part, the product of an inherent selection bias. Only those parents who believed, or at least hoped, that laser-assisted myringotomy would be the best treatment agreed to participate.

Further research is necessary to define optimum technical parameters and management algorithms, as well as to identify appropriate candidates for intermediate-duration middle ear ventilation with laser-assisted myringotomy. Many of these issues are already being investigated in prospective, multicenter studies.

We hope that improved knowledge of the pathophysiology of otitis media, as well as an understanding of the particular manifestations of otitis media in individual patients, will help identify those children who are most likely to benefit from laser-assisted myringotomy, and that refinements in laser-assisted myringotomy techniques will allow us to provide treatment with optimal patient comfort.

From the Division of Pediatric Otolaryngology, Alfred I. duPont Hospital for Children, Wilmington, Del., and the Department of Otolaryngology, Jefferson Medical College, Thomas Jefferson University, Philadelphia.

At the time this study was eondueted, none of the authors was affiliated with the Sharplan Company. After the study was completed, the authors participated in a study with partial funding from Sharplan, and Drs. Reilly and Cook have since become speakers for the Sharplan Company.

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