Laser-assisted myringotomy: promises and problems

February 2003

Tympanostomy tubes permit a tympanic membrane myringotomy to remain patent for many months, which is sufficient time to restore the middle ear mucosa back to a healthy state. Simple myringotomy without the insertion of a tympanostomy tube usually remains patent for a few days, an insufficient interval to reliably restore health to the middle ear in most cases with chronic otitis media with effusion (OME). After simple myringotomy or tympanocentesis (middle ear aspiration), 80% of children with chronic mucoid OME (secretory otitis media) will not show any improvement in their condition when the tympanic membrane heals. In the past, failed methods for achieving longer interval patency of a fenestration procedure included electrocautery or chemically burning a hole in the eardrum.

Laser-assisted myringotomy is considered by several otolaryngologists as an efficient, rapid, reduced-cost means of achieving short-term middle ear ventilation in an office setting, without the necessity of general anesthesia. Goode first introduced the concept of using a laser to create an opening that would remain patent for several weeks in 1982. The FDA first approved the use of a flash scanner to magnify and pinpoint the target area of a CO₂ laser otoscope, in November 1996.

The actual otoscope device (OtoLAM laser technology, Sharplan/Lumenis, Needham, MA) consists of a t-shaped light source with mirror system, where one end has an interchangeable ear speculum and the other is attached to a video camera. The base of the T is an articulated mirror arm that is attached to the computer-guided scanner system that illuminates the target area and projects its image on a video screen. The duration of the laser-produced tympanic membrane fenestration (before spontaneous healing occurs) is determined by the diameter of the fenestration, which in turn is influenced by duration, and energy level of the laser beam on the eardrum and the viscosity of liquid in the middle ear.

The CO₂ laser otoscope consists of a mirror system with an integrated video camera coupled to a computer-controlled scanner system that increases the size of the opening. The diameter of the laser burn is variable, ranging from 1 to 3 mm and the applied power from 1W to 40W (average equals 12W to 15W) that feels like a sharp sting (similar to being snapped by a rubber band) on an eardrum without anesthesia. The laser-assisted otoscope has been demonstrated to pediatricians at annual medical meetings, such as the American Academy of Pediatrics. Topical anesthesia is achieved by 20% tetracaine-solution dropped onto a cotton pledget or commercially available otowick inserted adjacent to the eardrum. Excellent anesthesia of the tympanic membrane is achieved in about 45 to 60 minutes but adequate anesthesia may be achieved in as little as 20 to 30 minutes. Most infants and young children are awake but restrained during the laser procedure while cooperative older children need not be restrained. The pre-set controlled CO₂ laser beam burns a small 2 mm hole with a variable diameter through the layers of the tympanic membrane in about 0.1 to 0.2 seconds. After the opening is produced, many otolaryngologists apply aural suction to quickly drain the middle ears of effusion. Total procedure time after achieving local anesthesia is about five minutes. Ototopical antibiotic drops are frequently prescribed for about five days after the laser fenestration procedure, similar to their use postoperatively after myringotomy and insertion of ventilation tubes.

In the past three years, results of the efficacy of laser-assisted myringotomy studies from Israel, Germany and the United States have been, in general, positive. The major use for laser-assisted myringotomy is for short-term in-office ventilation of the middle ear and resolution of chronic otitis media with effusion. Using only topical anesthesia in the office setting, it is also possible to rapidly insert a ventilation tube into the tympanostomy site made by the CO₂ laser beam, again, without the necessity of general anesthesia. The technique is also said to be able to instantaneously treat children with acute otitis media (AOM) without the need for systemic antibiotics. Cultures of middle ear fluid are easily taken from the myringotomy site and antibiotic therapy is targeted against any recovered middle ear bacterial pathogen. The procedure can be repeated for future recurrences of chronic OME or acute recurrent or intractable otitis media.

Advantages of laser-assisted myringotomy over myringotomy with insertion of ventilation tubes under general anesthesia include rapidity and safety of the procedure, and avoidance of long-term care of tympanostomy tubes. Unlike tympanostomy tubes, tympanosclerotic scarring of the eardrum with laser-assisted myringotomy is rare, as are post-tube atrophic areas. There is also no problem with the development of granulation tissue around a fenestration site that are commonly seen months to years after insertion of tympanostomy tubes.

Resolution of OME was determined by clinical examination, audiometry and tympanometry in a multicenter study of the effectiveness of adenoidectomy and laser-assisted myringotomy. Of 96 treated ears in 50 children, resolution was documented in 88%, 86% and 83% respectively, and at 30, 60 and 90 days in children who otherwise may have had tympanostomy tube placement.

The laser-assisted CO₂ otoscope equipment is expensive, costing approximately $60,000. Although the sales representatives suggest that reimbursement for the procedure is about the same as that for myringotomy and tympanostomy tube insertion, the reality of managed care reimbursement is far removed from the rosy projections suggested. There is no specific CPT code for laser-assisted fenestration of the tympanic membrane and it is usually coded as a simple in-office myringotomy procedure. Actual reimbursement ranges from $60 to $100 for both ears. In Tennessee, Blue Cross/Blue Shield plans consider laser-assisted fenestration procedures as experimental surgery. The procedure is generally well accepted by surgeon and parent but is cost-effective only for the third party payer. When one considers the time it takes for explanation of the procedure to a patient’s parents, preparation of the patient, cleaning of the ear canals, insertion of the otowick, installation of the topical anesthetic, restraint on the examination table and operation of the laser otoscope — reimbursement barely covers the cost of the apparatus, use of an examination room and a surgeon’s time.

When there is thick mucoid middle ear effusion or the tympanic membrane is thickened from chronic inflammation, it is often necessary for multiple applications of the laser, set at higher power or duration of the laser beam. Moreover, thickness of the eardrum and/or copious middle ear effusion reduces the efficacy of the topical anesthetic making the procedure momentarily quite painful. Suction aspiration of middle ear liquid or gel makes a loud noise at the level of the eardrum that may frighten young patients and their parents who often vividly recall a very traumatic experience. In many cases of AOM there is a thickened, inflamed tympanic membrane. In such cases, higher laser energy levels and/or multiple laser pulses may be required to burn a hole in the tympanic membrane.

In a German study (Sedlmaier, et al) of the effectiveness of the procedure in 81 children (159 ears), laser myringotomy was successful with a single application of the laser source in 42% of the ears. Two or three applications were necessary to create a fenestration in 43% of the ears and multiple applications were necessary in 15% of ears. The median transtympanic ventilation time in the pediatric patients was 16 days with a range of eight to 34 days. When there were mucoid effusions in the middle ears (as was the case in 30% of the ears), the median closure time was 15 days. Although several other clinical studies found that the fenestration site remained patent for three weeks, Sedlmaier’s study is exceptionally well documented. Because the fenestration site remains patent for only two weeks before healing of the eardrum, at least one-third of all pediatric patients and a higher rate with infants, will still require tympanostomy tube insertion within one month following laser-assisted fenestration procedure. A procedure with such a failure rate is obviously a major source of discontent among parents, many otolaryngologists, and all third party payers. Linda Brodsky, MD, who investigated the procedure, has learned that children with Down syndrome who have stenotic ear canals, and children with chronic OME lasting six or more months with moderate conductive hearing loss, are particularly poor candidates for the procedure.

Conclusions

The high cost of equipment ($60,000) for laser assisted myringotomy prices this procedure out of range for most pediatricians. Although performed and initially used enthusiastically by many otolaryngologists — the high percentage of children who still require tympanostomy tubes (33% overall and as many as 70% of infants) and the insufficient reimbursement by third party payers — quickly dampens the enthusiasm of many physicians who purchased the equipment but were unable to pay it off with the procedure.

Although there are significant problems with the device and the procedure, they present an opportunity for further clinical studies to seek solutions to the problems. One question that comes to mind is the role of moderate sedation with fentanyl and a short-acting benzodiazapine such as midazolam (Versed, Roche) to reduce fear during the procedure; or application of aural suction at the level of the eardrum. Of course, otolaryngologists are masters of airway management, in the event of laryngospasm. Specific antagonists can be given to rapidly reverse the effects of the conscious sedation medications. This can be billed separately to the insurance companies. Another question is the possible role of dual fenestrations in the inferior quadrants of the tympanic membrane — one to serve as a ventilation hole and the other to aid in drainage of middle ear exudates. Is it really an advantage to apply suction to the fenestration site? Would the middle ear secretion or exudates drain spontaneously, particularly using a dual fenestration technique? Is there no way to convince third party payers that the procedure can be cost effective while still reimbursing it at a fair rate? Unless these problems are solved, there may be a few expensive white elephants gathering dust in offices of our otolaryngology colleagues.

For more information:

• Cohen D, Shechter Y, Gatt N, et al. Laser myringotomy in different age groups. Otolaryngol- Head Neck Surg. 2001:127:260-4.
• Sedlmaier B, Jivanjee A, Gutzler R, et al. Ventilation time of the middle ear in otitis media with effusion (OME) after CO₂ laser myringotomy. Laryngoscope. 2002;112:661-8.
• Brodsky L, Brookhauser P, Chait D, et al. Office-based insertion of pressure equalization tubes: The role of laser-assisted tympanic membrane fenestration. Laryngoscope. 1999;109:2009-14.
• Reilly JS. Laser-assisted myringotomy for otitis media:a feasibility study with short-term followup. Ear Nose Throat J. 2000:79:650-2, 654-7.