Abstract
Tympanoplasty repairs tympanic membrane perforations but also covers an umbrella of procedures characterized by surgery of the mastoid bone. Tympanoplasty is widely regarded as a beneficial procedure with an over 90% graft closure success rate and an over 80% return to normal hearing range. Though surgical technique and graft type are important in determining surgical outcomes of the procedure, results are most greatly correlated with location of the perforation. Marginal perforations are associated with the most complications in reconstruction of the tympanic membrane, lack of vascularization and limited membrane area delaying the healing process (4). Lasers have been used in medical procedures dating back to the 1960s. The advantage of infrared lasers such as CO2 are the precision of cutting and the smooth interaction with tissues (5). The CO2 laser is absorbed by the tympanic membrane and does not damage the middle ear while visible lasers penetrate and can damage the ear drum (6). This retrospective study of 150 patients from 2013–2016 assesses and demonstrates the viability of using carbon dioxide laser as an alternative to the traditional method for de-epithelialization of tympanic perforation margins during tympanoplasty. By comparing closure rates and audiogram data, this study reveals parameters of use, benefits and adverse outcomes on healing and hearing restoration with the CO2 laser-assisted method. Perforation closure rate of 91% and hearing improvement in 66% of patients was observed. Fourteen patients did not undergo closure of the tympanic membrane with an overwhelming majority of the 14 having large and marginal perforations.
Keywords: Laser, Tympanoplasty, Tympanic, Membrane, Perforation
Introduction
Tympanoplasty, the repair of the tympanic membrane may be done as a standalone procedure or combined with other otologic surgeries. Tympanoplasty is commonly used in chronic ear abnormalities, including cholesteatoma, atelectasis, and chronic tympanosclerotic otitis. Tympanoplasty is widely regarded as a beneficial procedure with an above 90% graft closure success rate on average and an over 80% return to normal hearing range. There are a variety of approaches to tympanoplasty that utilize different techniques such as open tympanoplasty, closed tympanoplasty, closed endoscopic tympanoplasty, and open endoscopic tympanoplasty [1, 2]. Though surgical technique and graft type are important in determining surgical outcomes of the procedure, results are most greatly correlated with location of the perforation. Greatest hearing preservation was found with anterior perforations, then posterior perforations, and finally with central perforations having the greatest hearing loss, Typically, tympanic membrane perforation size of less than 10% is not correlated with hearing loss [2, 3]. Marginal perforations, especially anterior, are associated with the most complications in reconstruction of the tympanic membrane, lack of vascularization and limited tympanic membrane area delaying the healing process [4].
Lasers have been used in medical procedures dating back to the 1960s. In otolaryngology, visible and infrared lasers have been used for skeletal and soft tissue pathology. The advantage of infrared lasers such as CO2 are the precision of cutting and the smooth interaction with biological tissues [5]. Laser freshening of the edges of the perforation has been preferred to conventional surgical closure of the perforation as it can be done rapidly and with less inflammation. The CO2 laser is absorbed by the tympanic membrane and does not damage the middle ear while the visible lasers penetrate the ear drum and can cause damage [5]. This retrospective study will assess and demonstrate the viability of using carbon dioxide laser as an alternative to the traditional method for de-epithelialization of tympanic perforation margins during a tympanoplasty procedure. By comparing closure rates and audiogram data, this study has the potential to reveal parameters of use, benefits and adverse outcomes on healing and hearing restoration with the CO2 laser-assisted method.
Methods
Patients who underwent tympanoplasty with carbon dioxide laser between 07/01/2013 and 09/01/2016 are identified. Inclusion criteria consists of those with CPT tympanoplasty codes 69631, 69632, 69641, 69642, 69643, and 69644. A retrospective analysis of all patients in aforementioned time period in a consecutive case series and was conducted. Age, record of previous tympanoplasty, underlying disease (mastoiditis or cholesteatoma), marginal versus central perforation, perforation size, graft type (cartilage vs fascia) ossicle status, CPT code, pre-operative Air–Bone Gap on Audiogram, post-operative Air–Bone Gap on Audiogram, rate of closure, complications, and length of post-operation follow-up appointment from surgery date were obtained. Full Audiogram and Tympanogram data were examined. These factors are collected to make sure that all the components that could be contributing to the success of tympanoplasty are accounted for. The carbon dioxide laser method will be compared to the standard mechanical method of de-epithelialization. Statistical analysis will be done to compare the closure rate and hearing improvement of carbon dioxide laser tympanoplasty using a non-parametric test compared to the conventional tympanoplasty technique.
The patient is prepped and draped in typical fashion for tympanoplasty. The surgery begins with CO2 laser on an Omniguide fiber to freshen the edges of the tympanic membrane perforation, essentially de-epithelializing with minimal to no bleeding. It is set at 4 W continuous but applied with an intermittent pulse. One mm or less is removed from the edges of the perforation. If it is marginal, the laser creates a raw edge along the annulus. Thereafter surgery continues in an Underlay Technique when the temporalis fascia is employed or a butterfly technique when cartilage is used. Depending on the case a fascia graft or cartilage graft is used. The ear is packed with gelfoam only when the temporalis facia is harvested. Antibiotics drops are begun one to 2 weeks postoperatively to help remove debris.
Results
Overall, 150 patients between the dates of 07/01/2013 and 09/01/2016 underwent CO2 laser tympanoplasty performed by one attending surgeon, the senior author. Patients had various underlying diseases that led to tympanic membrane perforation necessitating correction with tympanoplasty. Common diseases included mastoiditis, cholesteatoma, and oterosclerosis among others. Size of perforation ranged from 2 mm to encompassing the totality of the tympanic membrane. In Table 1, perforation size is described as small, medium and large. Small perforations were 2–3 mm or 20% of the tympanic membrane, medium perforations were 4 mm or 20–40% of the tympanic membrane, and large perforations were 5 mm or above 40% of the tympanic membrane. Additionally, the pre-tympanoplasty Audiogram Air–Bone Gap was broken down into categories of under 10, 10–30, or over 30 dB conductive hearing loss (Fig. 1).
Table 1.
Case-specific details of the 14 failed tympanoplasties
| Patient number | Perforation type | Perforation size | Underlying condition |
|---|---|---|---|
| 24 | Anterior marginal perforation | Medium | Cholesteatoma |
| 25 | Marginal posterior perforation | Large | None |
| 31 | Marginal perforation | Large | None |
| 39 | Central perforation | Large | None |
| 49 | Posterior marginal perforation | Large | Cholesteatoma |
| 56 | Unknown | Unknown | None |
| 65 | Unknown | Unknown | Mastoiditis |
| 66 | Unknown | Unknown | Mastoiditis and cholesteatoma |
| 79 | Inferior perforation | Small | Cholesteatoma |
| 85 | Central perforation | Large | Chronic external otitis |
| 87 | Central perforation | Medium | Otitis media |
| 94 | Central perforation | Small | Chronic ear infection |
| 149 | Marginal perforation | Medium | None |
| 154 | Anterior marginal perforation | Large | Otitis media |
Fig. 1.
Pre-tymplanoplasty demographic data
Among the 65 patients for whom perforation size was documents, there were 35 small, 11 medium and 19 large perforations. Regarding perforation type, there were 7 anterior, 35 central, 7 posterior, 16 marginal, 3 inferior, 2 superior and 5 posterior superior quadrant perforations. Among the 150 patients studied, 136 patients had successful tympanoplasty closure rates for a total success rate of 91%.
Table 1 investigates the 14 patients that had failed tympanoplasties.
It is evident that marginal perforations and large perforations were common features of the failed tympanoplasties. 55% of the surgeries with perforation type data were some form of marginal perforation. Among the 16 marginal perforations, 8 were repaired and 6 failed with a closure rate of 57%. Additionally, 55% of the surgeries with size data were large perforations and another 27% were medium in size.
To compare conductive hearing improvements pre and post tympanoplasty, Air–Bone Gaps prior to and after the procedure were compared for patients who had both audiograms in their chart. Table 2 displays pre and post tympanoplasty audiograms for 54 patients.
Table 2.
Average pre- and post-tympanoplasty air–bone gap values
| Average pre-tympanoplasty air–bone gap: 27.5 | Average post tympanoplasty air–bone gap: 23 |
The average pre-tympanoplasty Air–Bone Gap measured 27.5 while the average post-tympanoplasty Air–Bone gap measured 23. This indicates a 4.5 dB improvement (Table 3).
Table 3.
Change in air–bone gaps after laser tympanoplasty
| Number of patients | Air–bone gap range |
|---|---|
| 37 | Less than 10 |
| 16 | 10–30 |
| 1 | Over 30 |
Thirty-five patients showed a decrease in air–bone gap following tympanoplasty while 16 showed an increase and 4 showed no change. 66% of patients showed improved air–bone conduction. Of the 150 patients that underwent laser tympanoplasty, 27 were patients that underwent a tympanoplasty in the past. Among the patients with documented graft type, there were 53 patients with cartilage while there were 75 patients with fascial grafts.
Figure 2 depicts the images of the CO2 laser tympanoplasty during a procedure by the senior author. The image depicts the tympanic membrane perforation and the actions of the CO2 laser to close the perforation.
Fig. 2.
CO2 laser tympanoplasty prior to CO2 laser (top) and post CO2 laser (bottom)
Discussion
The tympanic membrane closure rate of 91% and improved air–bone conduction rate of 66% are comparable to but not greater than the hypothesized values for closure and conduction which were above 90% closure and above 80% hearing improvement [1, 2]. There are significant aspects of this retrospective chart review that account for this finding. Of the 150 patients seen and operated on by the senior author, only 54 patients had documented pre and post tympanoplasty audiograms. A patient with a good surgical outcome often would not return for followup and thus their successful closure and decrease in air–bone gap would not be documented. Oftentimes, patients seen by in the clinic have undergone previous tympanoplasties and thus are more likely to have worse hearing outcomes as revision surgery [6]. Twenty-seven out of 150, or 18% the patients have undergone a prior tympanoplasty.
Regarding the 14 failed tympanoplasties, 55% of the failed outcomes were marginal perforations and 55% were large perforations. Marginal perforations render a poor prognosis and large perforations are intrinsically more challenging to correct with a graft [7]. The total marginal perforation closure rate of 57% is an achievement itself given that marginal perforations are notoriously difficult to repair.
Perforation type is an important determinant of surgical outcome. Central and marginal perforations show the least improvement in hearing while anterior perforations are the most favorable [2]. Out of the 75 patients for whom there was perforation type data, 68% had central or marginal perforations. Thus, a majority of the patients had perforation types that were least likely to be corrected by any form of tympanoplasty. Another variable that influences closure and conduction rates is the type of graft used. Although cartilage grafts have gained recent prominence because of their durability and association with improved hearing outcomes, fascial grafts remain the standard [8]. The majority of the patients had a fascial as opposed to a cartilage graft, 75 fascial versus 53 cartilage grafts. This supports that the lower hearing and conduction rates seen with the patients may have been more influenced by fascial graft which has a worse outcome than cartilage grafts.
While the outcomes are comparable to the traditional technique, cost is an important factor that should be considered. Each oto-omniguide CO2 fiber costs 600 dollars and with 150 patients operated, this yields a total of 900,000 dollars. With essentially equivalent outcomes, it may become difficult to support, unless the cost of laser fibers decreases.
Conclusion
CO2 laser assisted tympanoplasty appears to be a feasible technique. The tympanic membrane closure rates and hearing outcomes are comparable to the literature especially when considering the preponderance of revision cases.
Compliance with Ethical Standards
Conflict of interest
None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript.
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