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Thermal myringotomy for eustachian tube dysfunction in hyperbaric oxygen therapy
Thermal myringotomy for eustachian tube dysfunction in hyperbaric oxygen therapy STANLEY E. POTOCKI, MD, and DOUGLAS S. HOFFMAN, MD, PhD, San Antonio, Texas
Otolaryngologists are frequently asked to manage eustachian tube dysfunction (ETD) in patients undergoing hyperbaric oxygen therapy (HBO). HBO patients with intractable ETD currently are treated by tympanostomy tube placement; typically, these tubes are indwelling far longer than is required by the duration of HBO. Also, tubes in this population are associated with higher complication rates of persistent perforation and otorrhea. We investigated the use of thermal myringotomy as an alternative to tympanostomy tube placement in this clinical setting. Potentially, thermal myringotomy avoids the risks and complications associated with indwelling tympanostomy tubes and would be a temporally more appropriate treatment during short- and intermediate-term HBO. In this study 13 patients undergoing HBO who would have required tympanostomy tube placement instead underwent bilateral thermal myringotomies. At the fifth postoperative week, 96% of myringotomies were patent; this duration is adequate for most HBO courses. No patient required a second myringotomy for premature closure. The persistent perforation rate was 15% (at the end of 6 months), which compares favorably with the rate observed with tympanostomy tubes in this unique population of poor wound healers. Only 1 patient had otorrhea; this resolved with dry ear precautions. This study demonstrates thermal myringotomy to be an effective technique for middle ear ventilation in patients undergoing HBO in whom ETD develops. (Otolaryngol Head Neck Surg 1999;121:185-9.)
From the University of Texas Health Science Center at San Antonio. Xomed (Jacksonville, FL) provided the devices at no cost, but no other financial relationship exists between Xomed and either author. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head Neck Surgery, San Antonio, TX, September 13-16, 1998. Reprint requests: Stanley E. Potocki, MD, Department of Otolaryngology–Head and Neck Surgery, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78284-7777. Copyright © 1999 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/99/$8.00 + 0 23/1/96546
Intermediate-term (20 to 30 treatments) hyperbaric oxygen therapy (HBO) is an important adjuvant for treatment of chronic infection and nonhealing wounds. Delays in therapy caused by eustachian tube dysfunction (ETD) occur in 10% to 40% of HBO patients.1,2 Currently, such patients are treated by myringotomy with ventilation tube placement. Typically, these tubes are indwelling far longer than is required by the duration of HBO therapy. Also, complications are associated with tympanostomy tubes. In 1983 Tos et al3 reported the incidence of tympanosclerosis after tube extrusion to be 40% to 50%. This percentage contrasts with Maw’s4 report of a 3% incidence of tympanosclerosis in a population that had not undergone any otologic surgery. Premature extrusion, tube otorrhea, persistent perforation, tube plugging, and inadvertent placement of the tube in the middle ear space are other reported complications of tympanostomy tubes. We investigated the use of thermal myringotomy as an alternative treatment to tympanostomy tube placement for ETD in patients undergoing HBO. In this study we sought to determine (1) whether thermal myringotomy (without tube placement) provides a myringotomy that would remain patent throughout HBO treatment with an acceptable complication rate, and (2) how the cost of thermal myringotomy compares with the current standard of care, tympanostomy tube placement. METHODS AND MATERIAL The protocol and consent form were approved by the institutional review boards of the University of Texas Health Science Center at San Antonio, the University Health System, and the Southwest Texas Methodist Hospital. Informed written consent was obtained in all cases. From July 10, 1997, through April 3, 1998, 13 patients underwent thermal myringotomy. Eleven of the subjects had delayed HBO because of ETD. Medical management with nasal decongestants and the Valsalva maneuver had failed in these patients. In 2 cases the referral was for prophylactic middle ear ventilation in patients who had an urgent need for HBO, and any delay caused by ETD might have compromised their health. Patients were offered thermal myringotomy versus tympanostomy tube placement. Children were excluded from participation because of their infrequent need for HBO. Routine history was obtained with attention to otologic history and symptoms, 185
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Fig 1. Thermo Tip 2 device used to perform thermal myringotomies.
as well as systemic factors that could complicate wound healing. An otolaryngologic examination was performed with notation of otologic evidence of barotrauma. Preprocedure audiologic testing consisted of middle ear immitance measures (tympanogram, equivalent volume, ipsilateral acoustic reflex threshold at 1000 Hz) and pure-tone audiometry (octave frequencies 250 to 8000 Hz). Thermal myringotomies were performed bilaterally after canal block with 1% lidocaine. Myringotomy sizes were estimated by comparing the hole with a Day hook of known length. Patients were then observed weekly by one of the authors (S.E.P.) for otologic symptoms and examination of perforations. For perforations lasting more than 5 to 6 weeks, less frequent follow-up was done (every 3 to 6 weeks), once the patient had completed HBO therapy. Follow-up continued until perforation closure or after 6 months of persistent perforation. Myringotomies were performed with the Thermo Tip 2 (Xomed, Jacksonville, FL) (Fig 1). The Thermo Tip 2 consists of a handpiece containing an AA battery attached to a probe tip. A simple circuit is completed by pressing the on/off switch to heat the probe tip (the probe is insulated except at the tip). The tip acquires a dull red glow within seconds of switch activation. Output is 1.5 V DC, and tip temperature maximum is 871°C (Personal communication, Xomed, November 10, 1997). Material cost to perform thermal myringotomy was obtained by personal communication with Xomed because the device is not yet commercially available. Xomed plans to reintroduce the Thermo Tip 2 for sale in the United States later this year. The materials cost for tympanostomy tubes was calculated from the February 1, 1998, Xomed Domestic Price List. Statistical analysis was done with parameter estimation testing. The equation for standard normal approximation for estimating a proportion was used to determine the percentage of perforations patent at the fifth postoperative week.5 The proportions of persistent perforations, hearing change, and tympanosclerosis were also assessed for significance by parameter estimation testing. RESULTS
Patient characteristics are given in Table 1. All patients except patient 7 had nonhealing lower extremi-
Fig 2. Scatterplot of perforation time to close as a function of perforation area. Perforations open at 25 weeks did not close and are defined as persistent perforations.
ties as their indications for HBO. Patient 7 had sustained head trauma and was receiving HBO to treat an exposed calvarium. No patient had prior otologic surgery or barotrauma. In this study 96% of perforations (25 of 26) were patent at the fifth postoperative week (95% CI, 89% to 99%). For the holes that closed (22 of 26), the range of patency length was 26 to 182 days. Figure 2 displays the perforation size related to time to closure. No perforation smaller than or equal to 6 mm2 failed to close. No patient had further otalgia or a delay in treatment with HBO. Also, no patient required a second procedure to complete HBO. One patient received 10 additional HBO treatments after closure of the perforations. This patient did not have ETD, so a second procedure was unnecessary. One patient whose perforations had healed by the completion of HBO required a second course of therapy 4 months later. Thermal myringotomies were repeated; the patient finished HBO, and the perforations healed without complication by the seventh postoperative week. This patient was counted only once for statistical analysis. No symptoms of vertigo were reported. One patient reported a change in hearing but declined a repeat audiogram. Slight postclosure scarring of the tympanic membrane at the myringotomy site was seen in 1 of 26 (4%) ears undergoing the procedure (95% CI, 1% to 12%). Subjects were instructed to observe dry ear precautions, and none had infection. The myringotomy size ranged from 2 × 2 mm to 3 × 3 mm. Of 26 myringotomies performed, 4 failed to close by 6 months for a rate of 15% (95% CI, 1% to 29%). The 4 perforations occurred in 2 patients; both patients have been scheduled for myringoplasty.
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Table 1. Patient characteristics Patient no.
Sex
Age (y)
Comorbidity
Barotrauma
Perforation size (mm)
Days to close
1 2 3 4 5 6 7 8 9 10 11 12 13
F M F M F F M M M M M M M
62 77 75 46 51 49 52 40 57 50 33 70 29
DM DM DM, PVD DM DM PVD Trauma PVD DM, PVD DM Osteomyelitis DM, PVD, renal failure DM
TM-H TM-H TM-H TM-H None TM-H, HT None None TM-H, HT TM-H None HT TM-H
3 × 3 AU 2 × 2 AS, 3 × 2 AD 3 × 3 AU 2.5 × 2.5 AU 2.5 × 2.5 AU 3 × 3 AU 2.5 × 2.5 AS, 2.5 × 3 AD 2.5 × 2.5 AU 2.5 × 2.5 AS, 3 × 3 AD 2 × 2 AU 2 × 2 AU 2.5 × 2 AU 2.5 × 2 AS, 2.5 × 3 AD
29-31 AS, 26-29 AD 29-38 AU 28-35 AU Failed to close AU 42-50 AS, 35-42 AD 43-59 AS, 63-70 AD Failed to close AU 144-158 AS, 30-36 AD 182-210 AS, 52-66 AD 52-70 AS, 38-52 AD 28-34 AU 28-34 AU 29-39 AS, 39-42 AD
DM, Diabetes mellitus; PVD, peripheral vascular disease; TM-H, tympanic membrane hemorrhage; HT, hemotympanum; AS, left ear; AD, right ear; AU, both ears.
Table 2 shows a materials cost comparison of thermal myringotomy with tympanostomy tube placement. Although the cost varies depending on the type of tube used, the material cost of thermal myringotomy is comparable with that of placement of even the least expensive type of tube. DISCUSSION
Thermal myringotomy is not a new technique. Ventilating the middle ear without use of a tube has been the subject of numerous studies. Soderberg et al6 studied time to closure as well as morphologic changes of the tympanic membrane in the rat using various methods of myringotomy. Closure times for lancet, diathermy, and CO2 laser were 9 to 11 days, 12 to 18 days, and up to 24 days, respectively. Morphologic changes of the tympanic membrane were also compared with those of a group of patients who received tympanostomy tubes. The tube group had the greatest incidence of tympanosclerosis. In the study by Soderberg et al,6 less tympanic membrane scarring occurred when a tube was not inserted; however, a short duration of ventilation was apparent. In human beings, Goode and Schulz7 made 2-mmdiameter thermal myringotomies in 10 patients with serous otitis media; all myringotomies were patent at 3 to 4 weeks, and all had closed by 6 weeks. Saito et al8 attempted to create a permanent perforation with thermal myringotomies. In 8 patients, more than 25% of the entire tympanic membrane was perforated; these myringotomies were all patent at 6 months. Perforations smaller than 25% closed by 3 months, and time to closure directly correlated with perforation size. Ruckley and Blair9 compared thermal myringotomy with tympanostomy tubes in 36 children with serous otitis media,
Table 2. Materials cost for thermal myringotomy versus tympanostomy tubes Material
Cost ($)
Thermal myringotomy Tympanostomy tubes* Blade Knife Tube Grommet
28.00/Device
*($12.86
6.60 9.20 15.80 12.86
to $15.80/tube)2 + $6.60 = $32.32 to $38.20.
using each child as his or her own control. The dimensions of the perforations were 3 × 1.5 mm. All thermal myringotomies closed by 42 days, and the average length of patency was 26 days. They concluded that thermal myringotomy does not have a place in the treatment of serous otitis media in children because of the inadequate duration of the perforation. Given the limited duration of HBO, a method yielding short-term tympanic membrane perforations may have utility in this subset of patients. A recent retrospective study by Clements et al10 examined the complication rate in 45 patients in whom tympanostomy tubes were placed for ETD in HBO. The overall complication rate was 38%. Although otitis media was evident in only 1 patient before surgery, otorrhea developed in 29%, making this the most common complication. Hearing loss was recorded in 22%, and 4% reported new-onset tinnitus. A persistent perforation rate of 16% was stated, but of 45 patients studied (90 ears), almost half received no follow-up. Of those patients with follow-up, 32 of their ears still had tubes, 20 had healed tympanic membranes after extrusion, and
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A
B
Fig 3. A, Tympanic membrane after thermal myringotomy. B, Same tympanic membrane after closure.
7 had persistent perforations. Therefore, of patients with adequate follow-up after extrusion, 7 of 27 ears (26%) had persistent perforations. In the persistent perforation group, the length of intubation was 1 year in 1 ear, 6 months in 1 ear, less than 3 months in 4 ears, and unknown in 2 ears. The authors did not specify which types of tubes were used. Our study showed that a 2- to 3-mm × 2- to 3-mm thermal myringotomy provides middle ear ventilation of sufficient duration for most cases of intermediateterm HBO. The patients were examined at approxi-
Otolaryngology– Head and Neck Surgery September 1999
mately weekly intervals, so the exact length of patency is unknown. Rather, the last postoperative visit with a patent hole was defined as the day before closure, thus giving the most conservative estimate for time to closure. Defining patency in this way does not overestimate the length of patency and provides more meaningful data to determine whether thermal myringotomy provides ventilation long enough to complete standard HBO therapy. It is significant that no further treatment delays (caused by ETD) occurred after thermal myringotomy. One patient had premature closure of the myringotomy but, fortunately, was able to complete another 10 treatments without incident. All other perforations were open for the full course of treatment. No otalgia or vertigo was reported. There were no episodes of infection. One patient who underwent prophylactic myringotomies had bilateral serous effusions at the time of the procedure. This patient’s otorrhea resolved over 2 to 3 weeks and did not recur. No other patient had otorrhea. One patient had decreased hearing and was in the group of patients with persistent perforations. Unfortunately, this patient declined a repeat audiogram. Slight scarring of the tympanic membrane occurred in only 1 ear. By otoscopy, in most cases it was difficult to detect a difference between the healed site and the rest of the tympanic membrane (Fig 3). The persistent perforation rate (failure to close by 6 months) was 15%. In the studies with similar-sized perforations,7,9 no persistent perforations occurred. In the study by Saito et al,8 in which permanent perforations were a desired outcome, the only perforations patent at 6 months were those initially larger than 25% of the tympanic membrane. One explanation for our higher rate of persistent perforation is that patients undergoing HBO constitute a unique population. Many of these patients have diabetes and/or peripheral vascular disease; some have even undergone amputation of a nonhealing extremity. One shortcoming of this study is the lack of a direct comparison with a similar group treated by tympanostomy tube placement. However, complications of tympanostomy tube placement in this population were recently reviewed by Clements et al.10 Our persistent perforation rate (15%) compares favorably with the rate they observed (26%), and otorrhea was a less frequent complication in our series (4% vs 29% in Clements et al). Although their study size was 45 patients with 90 perforations, only 27 ears had adequate follow-up after tube extrusion. Therefore the study sizes are equivalent for analyzing persistent perforation rates. This comparison suggests that thermal myringotomy has a similar or better spectrum of complications relative to tympanos-
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tomy tube placement. A randomized trial comparing the 2 methods would definitively address this question. The cost of thermal myringotomy compares well with that of tympanostomy tube insertion. Thermal myringotomy is comparable with placement of even the least expensive type of tube. The time to perform the procedure was not recorded. It does seem obvious, though, that thermal myringotomy is faster. Once the canal block is performed (or whatever manner selected to provide anesthesia), making the myringotomy takes only seconds. In 1 case, placement of the myringotomy in a region of tympanic membrane hemorrhage ruined the tip of the device because it became coated in char. Attempts at removing the char from the device resulted in breakage of the fine wire tip. Therefore, to save time and additional cost of a second unit, we recommend not placing the myringotomy at a site of membrane hemorrhage. CONCLUSION
Thermal myringotomy provides middle ear ventilation of sufficient duration for intermediate-term HBO. It compares well with tympanostomy tube material cost, is quicker to perform, and may have less otorrhea and persistent perforations than tympanostomy tube placement. Further study with smaller myringotomies is warranted to determine whether the persistent perforation rate could be decreased without also compromising the needed duration of ventilation. Specifically, a 2- × 2mm myringotomy should be attempted because none of the holes this size failed to heal (Table 1). Because thermal myringotomy provides a closer match between
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middle ear ventilation duration and need, it should be considered as a treatment option in this population. We thank Drs Merrit Davis, Ellen Duncan, and Richard Heimbach for the kind referral of their patients. We also thank Dr Susan Marenda for her assistance in patient accrual, Dr Thomas J. Prihoda (PhD, statistics) for statistical guidance, and Xomed (Jacksonville, FL) for providing the Thermo Tip 2 devices at no charge. REFERENCES 1. Meinje NG. Hyperbaric oxygen and its clinical value. Springfield: Charles C Thomas Publishers; 1970. p. 3-93. 2. Fernau JL, Hirsch BE, Derkay C, et al. Hyperbaric oxygen therapy: effect on middle ear and eustachian tube function. Laryngoscope 1992;102:48-52. 3. Tos M, Bonding P, Poulsen GP. Tympanosclerosis of the drum in secretory otitis after insertion of grommets. A prospective comparative study. J Laryngol Otol 1983;97:489-96. 4. Maw AR. Development of tympanosclerosis in children with otitis media with effusion and ventilating tubes. J Laryngol Otol 1991;105:614-7. 5. Marks RG. Designing a research project, the basics of biomedical research methodology. New York: Van Nostrand Reinhold; 1982. p. 130-2. 6. Soderberg S, Hellstrom S, Stenfors LE. Tympanic membrane changes resulting from different methods of transmyringeal middle ear ventilation. Am J Otolaryngol 1985;6:237-40. 7. Goode RL, Schulz W. Heat myringotomy for the treatment of serous otitis media. Otolaryngol Head Neck Surg 1982;90:764-6. 8. Saito H, Miyamoto D, Kishimoto S, et al. Burn perforation as a method of middle ear ventilation. Arch Otolaryngol 1978;104: 79-81. 9. Ruckley RW, Blair RL. Thermal myringotomy (an alternative to grommet insertion in childhood secretory otitis media?). J Laryngol Otol 1988;102:125-8. 10. Clements KS, Vrabec JT, Mader JT. Complications of tympanostomy tubes inserted for facilitation of hyperbaric oxygen therapy. Arch Otolaryngol Head Neck Surg 1998;124:278-80.
Controversies and Advances in Head and Neck Surgery
This course, presented by the Cleveland Clinic Foundation Department of Otolaryngology, will be held October 29-30, 1999, at the Marriott Key Center, Cleveland, OH. For further information, contact the Department of Continuing Medical Education, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland OH 44195; phone, 216444-5696 or 800-762-8173; fax, 216-445-9406.
Otolaryngologists are frequently asked to manage eustachian tube dysfunction (ETD) in patients undergoing hyperbaric oxygen therapy (HBO). HBO patients with intractable ETD currently are treated by tympanostomy tube placement; typically, these tubes are indwelling far longer than is required by the duration of HBO. Also, tubes in this population are associated with higher complication rates of persistent perforation and otorrhea. We investigated the use of thermal myringotomy as an alternative to tympanostomy tube placement in this clinical setting. Potentially, thermal myringotomy avoids the risks and complications associated with indwelling tympanostomy tubes and would be a temporally more appropriate treatment during short- and intermediate-term HBO. In this study 13 patients undergoing HBO who would have required tympanostomy tube placement instead underwent bilateral thermal myringotomies. At the fifth postoperative week, 96% of myringotomies were patent; this duration is adequate for most HBO courses. No patient required a second myringotomy for premature closure. The persistent perforation rate was 15% (at the end of 6 months), which compares favorably with the rate observed with tympanostomy tubes in this unique population of poor wound healers. Only 1 patient had otorrhea; this resolved with dry ear precautions. This study demonstrates thermal myringotomy to be an effective technique for middle ear ventilation in patients undergoing HBO in whom ETD develops. (Otolaryngol Head Neck Surg 1999;121:185-9.)
From the University of Texas Health Science Center at San Antonio. Xomed (Jacksonville, FL) provided the devices at no cost, but no other financial relationship exists between Xomed and either author. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head Neck Surgery, San Antonio, TX, September 13-16, 1998. Reprint requests: Stanley E. Potocki, MD, Department of Otolaryngology–Head and Neck Surgery, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78284-7777. Copyright © 1999 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/99/$8.00 + 0 23/1/96546
Intermediate-term (20 to 30 treatments) hyperbaric oxygen therapy (HBO) is an important adjuvant for treatment of chronic infection and nonhealing wounds. Delays in therapy caused by eustachian tube dysfunction (ETD) occur in 10% to 40% of HBO patients.1,2 Currently, such patients are treated by myringotomy with ventilation tube placement. Typically, these tubes are indwelling far longer than is required by the duration of HBO therapy. Also, complications are associated with tympanostomy tubes. In 1983 Tos et al3 reported the incidence of tympanosclerosis after tube extrusion to be 40% to 50%. This percentage contrasts with Maw’s4 report of a 3% incidence of tympanosclerosis in a population that had not undergone any otologic surgery. Premature extrusion, tube otorrhea, persistent perforation, tube plugging, and inadvertent placement of the tube in the middle ear space are other reported complications of tympanostomy tubes. We investigated the use of thermal myringotomy as an alternative treatment to tympanostomy tube placement for ETD in patients undergoing HBO. In this study we sought to determine (1) whether thermal myringotomy (without tube placement) provides a myringotomy that would remain patent throughout HBO treatment with an acceptable complication rate, and (2) how the cost of thermal myringotomy compares with the current standard of care, tympanostomy tube placement. METHODS AND MATERIAL The protocol and consent form were approved by the institutional review boards of the University of Texas Health Science Center at San Antonio, the University Health System, and the Southwest Texas Methodist Hospital. Informed written consent was obtained in all cases. From July 10, 1997, through April 3, 1998, 13 patients underwent thermal myringotomy. Eleven of the subjects had delayed HBO because of ETD. Medical management with nasal decongestants and the Valsalva maneuver had failed in these patients. In 2 cases the referral was for prophylactic middle ear ventilation in patients who had an urgent need for HBO, and any delay caused by ETD might have compromised their health. Patients were offered thermal myringotomy versus tympanostomy tube placement. Children were excluded from participation because of their infrequent need for HBO. Routine history was obtained with attention to otologic history and symptoms, 185
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Fig 1. Thermo Tip 2 device used to perform thermal myringotomies.
as well as systemic factors that could complicate wound healing. An otolaryngologic examination was performed with notation of otologic evidence of barotrauma. Preprocedure audiologic testing consisted of middle ear immitance measures (tympanogram, equivalent volume, ipsilateral acoustic reflex threshold at 1000 Hz) and pure-tone audiometry (octave frequencies 250 to 8000 Hz). Thermal myringotomies were performed bilaterally after canal block with 1% lidocaine. Myringotomy sizes were estimated by comparing the hole with a Day hook of known length. Patients were then observed weekly by one of the authors (S.E.P.) for otologic symptoms and examination of perforations. For perforations lasting more than 5 to 6 weeks, less frequent follow-up was done (every 3 to 6 weeks), once the patient had completed HBO therapy. Follow-up continued until perforation closure or after 6 months of persistent perforation. Myringotomies were performed with the Thermo Tip 2 (Xomed, Jacksonville, FL) (Fig 1). The Thermo Tip 2 consists of a handpiece containing an AA battery attached to a probe tip. A simple circuit is completed by pressing the on/off switch to heat the probe tip (the probe is insulated except at the tip). The tip acquires a dull red glow within seconds of switch activation. Output is 1.5 V DC, and tip temperature maximum is 871°C (Personal communication, Xomed, November 10, 1997). Material cost to perform thermal myringotomy was obtained by personal communication with Xomed because the device is not yet commercially available. Xomed plans to reintroduce the Thermo Tip 2 for sale in the United States later this year. The materials cost for tympanostomy tubes was calculated from the February 1, 1998, Xomed Domestic Price List. Statistical analysis was done with parameter estimation testing. The equation for standard normal approximation for estimating a proportion was used to determine the percentage of perforations patent at the fifth postoperative week.5 The proportions of persistent perforations, hearing change, and tympanosclerosis were also assessed for significance by parameter estimation testing. RESULTS
Patient characteristics are given in Table 1. All patients except patient 7 had nonhealing lower extremi-
Fig 2. Scatterplot of perforation time to close as a function of perforation area. Perforations open at 25 weeks did not close and are defined as persistent perforations.
ties as their indications for HBO. Patient 7 had sustained head trauma and was receiving HBO to treat an exposed calvarium. No patient had prior otologic surgery or barotrauma. In this study 96% of perforations (25 of 26) were patent at the fifth postoperative week (95% CI, 89% to 99%). For the holes that closed (22 of 26), the range of patency length was 26 to 182 days. Figure 2 displays the perforation size related to time to closure. No perforation smaller than or equal to 6 mm2 failed to close. No patient had further otalgia or a delay in treatment with HBO. Also, no patient required a second procedure to complete HBO. One patient received 10 additional HBO treatments after closure of the perforations. This patient did not have ETD, so a second procedure was unnecessary. One patient whose perforations had healed by the completion of HBO required a second course of therapy 4 months later. Thermal myringotomies were repeated; the patient finished HBO, and the perforations healed without complication by the seventh postoperative week. This patient was counted only once for statistical analysis. No symptoms of vertigo were reported. One patient reported a change in hearing but declined a repeat audiogram. Slight postclosure scarring of the tympanic membrane at the myringotomy site was seen in 1 of 26 (4%) ears undergoing the procedure (95% CI, 1% to 12%). Subjects were instructed to observe dry ear precautions, and none had infection. The myringotomy size ranged from 2 × 2 mm to 3 × 3 mm. Of 26 myringotomies performed, 4 failed to close by 6 months for a rate of 15% (95% CI, 1% to 29%). The 4 perforations occurred in 2 patients; both patients have been scheduled for myringoplasty.
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Table 1. Patient characteristics Patient no.
Sex
Age (y)
Comorbidity
Barotrauma
Perforation size (mm)
Days to close
1 2 3 4 5 6 7 8 9 10 11 12 13
F M F M F F M M M M M M M
62 77 75 46 51 49 52 40 57 50 33 70 29
DM DM DM, PVD DM DM PVD Trauma PVD DM, PVD DM Osteomyelitis DM, PVD, renal failure DM
TM-H TM-H TM-H TM-H None TM-H, HT None None TM-H, HT TM-H None HT TM-H
3 × 3 AU 2 × 2 AS, 3 × 2 AD 3 × 3 AU 2.5 × 2.5 AU 2.5 × 2.5 AU 3 × 3 AU 2.5 × 2.5 AS, 2.5 × 3 AD 2.5 × 2.5 AU 2.5 × 2.5 AS, 3 × 3 AD 2 × 2 AU 2 × 2 AU 2.5 × 2 AU 2.5 × 2 AS, 2.5 × 3 AD
29-31 AS, 26-29 AD 29-38 AU 28-35 AU Failed to close AU 42-50 AS, 35-42 AD 43-59 AS, 63-70 AD Failed to close AU 144-158 AS, 30-36 AD 182-210 AS, 52-66 AD 52-70 AS, 38-52 AD 28-34 AU 28-34 AU 29-39 AS, 39-42 AD
DM, Diabetes mellitus; PVD, peripheral vascular disease; TM-H, tympanic membrane hemorrhage; HT, hemotympanum; AS, left ear; AD, right ear; AU, both ears.
Table 2 shows a materials cost comparison of thermal myringotomy with tympanostomy tube placement. Although the cost varies depending on the type of tube used, the material cost of thermal myringotomy is comparable with that of placement of even the least expensive type of tube. DISCUSSION
Thermal myringotomy is not a new technique. Ventilating the middle ear without use of a tube has been the subject of numerous studies. Soderberg et al6 studied time to closure as well as morphologic changes of the tympanic membrane in the rat using various methods of myringotomy. Closure times for lancet, diathermy, and CO2 laser were 9 to 11 days, 12 to 18 days, and up to 24 days, respectively. Morphologic changes of the tympanic membrane were also compared with those of a group of patients who received tympanostomy tubes. The tube group had the greatest incidence of tympanosclerosis. In the study by Soderberg et al,6 less tympanic membrane scarring occurred when a tube was not inserted; however, a short duration of ventilation was apparent. In human beings, Goode and Schulz7 made 2-mmdiameter thermal myringotomies in 10 patients with serous otitis media; all myringotomies were patent at 3 to 4 weeks, and all had closed by 6 weeks. Saito et al8 attempted to create a permanent perforation with thermal myringotomies. In 8 patients, more than 25% of the entire tympanic membrane was perforated; these myringotomies were all patent at 6 months. Perforations smaller than 25% closed by 3 months, and time to closure directly correlated with perforation size. Ruckley and Blair9 compared thermal myringotomy with tympanostomy tubes in 36 children with serous otitis media,
Table 2. Materials cost for thermal myringotomy versus tympanostomy tubes Material
Cost ($)
Thermal myringotomy Tympanostomy tubes* Blade Knife Tube Grommet
28.00/Device
*($12.86
6.60 9.20 15.80 12.86
to $15.80/tube)2 + $6.60 = $32.32 to $38.20.
using each child as his or her own control. The dimensions of the perforations were 3 × 1.5 mm. All thermal myringotomies closed by 42 days, and the average length of patency was 26 days. They concluded that thermal myringotomy does not have a place in the treatment of serous otitis media in children because of the inadequate duration of the perforation. Given the limited duration of HBO, a method yielding short-term tympanic membrane perforations may have utility in this subset of patients. A recent retrospective study by Clements et al10 examined the complication rate in 45 patients in whom tympanostomy tubes were placed for ETD in HBO. The overall complication rate was 38%. Although otitis media was evident in only 1 patient before surgery, otorrhea developed in 29%, making this the most common complication. Hearing loss was recorded in 22%, and 4% reported new-onset tinnitus. A persistent perforation rate of 16% was stated, but of 45 patients studied (90 ears), almost half received no follow-up. Of those patients with follow-up, 32 of their ears still had tubes, 20 had healed tympanic membranes after extrusion, and
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A
B
Fig 3. A, Tympanic membrane after thermal myringotomy. B, Same tympanic membrane after closure.
7 had persistent perforations. Therefore, of patients with adequate follow-up after extrusion, 7 of 27 ears (26%) had persistent perforations. In the persistent perforation group, the length of intubation was 1 year in 1 ear, 6 months in 1 ear, less than 3 months in 4 ears, and unknown in 2 ears. The authors did not specify which types of tubes were used. Our study showed that a 2- to 3-mm × 2- to 3-mm thermal myringotomy provides middle ear ventilation of sufficient duration for most cases of intermediateterm HBO. The patients were examined at approxi-
Otolaryngology– Head and Neck Surgery September 1999
mately weekly intervals, so the exact length of patency is unknown. Rather, the last postoperative visit with a patent hole was defined as the day before closure, thus giving the most conservative estimate for time to closure. Defining patency in this way does not overestimate the length of patency and provides more meaningful data to determine whether thermal myringotomy provides ventilation long enough to complete standard HBO therapy. It is significant that no further treatment delays (caused by ETD) occurred after thermal myringotomy. One patient had premature closure of the myringotomy but, fortunately, was able to complete another 10 treatments without incident. All other perforations were open for the full course of treatment. No otalgia or vertigo was reported. There were no episodes of infection. One patient who underwent prophylactic myringotomies had bilateral serous effusions at the time of the procedure. This patient’s otorrhea resolved over 2 to 3 weeks and did not recur. No other patient had otorrhea. One patient had decreased hearing and was in the group of patients with persistent perforations. Unfortunately, this patient declined a repeat audiogram. Slight scarring of the tympanic membrane occurred in only 1 ear. By otoscopy, in most cases it was difficult to detect a difference between the healed site and the rest of the tympanic membrane (Fig 3). The persistent perforation rate (failure to close by 6 months) was 15%. In the studies with similar-sized perforations,7,9 no persistent perforations occurred. In the study by Saito et al,8 in which permanent perforations were a desired outcome, the only perforations patent at 6 months were those initially larger than 25% of the tympanic membrane. One explanation for our higher rate of persistent perforation is that patients undergoing HBO constitute a unique population. Many of these patients have diabetes and/or peripheral vascular disease; some have even undergone amputation of a nonhealing extremity. One shortcoming of this study is the lack of a direct comparison with a similar group treated by tympanostomy tube placement. However, complications of tympanostomy tube placement in this population were recently reviewed by Clements et al.10 Our persistent perforation rate (15%) compares favorably with the rate they observed (26%), and otorrhea was a less frequent complication in our series (4% vs 29% in Clements et al). Although their study size was 45 patients with 90 perforations, only 27 ears had adequate follow-up after tube extrusion. Therefore the study sizes are equivalent for analyzing persistent perforation rates. This comparison suggests that thermal myringotomy has a similar or better spectrum of complications relative to tympanos-
Otolaryngology– Head and Neck Surgery Volume 121 Number 3
tomy tube placement. A randomized trial comparing the 2 methods would definitively address this question. The cost of thermal myringotomy compares well with that of tympanostomy tube insertion. Thermal myringotomy is comparable with placement of even the least expensive type of tube. The time to perform the procedure was not recorded. It does seem obvious, though, that thermal myringotomy is faster. Once the canal block is performed (or whatever manner selected to provide anesthesia), making the myringotomy takes only seconds. In 1 case, placement of the myringotomy in a region of tympanic membrane hemorrhage ruined the tip of the device because it became coated in char. Attempts at removing the char from the device resulted in breakage of the fine wire tip. Therefore, to save time and additional cost of a second unit, we recommend not placing the myringotomy at a site of membrane hemorrhage. CONCLUSION
Thermal myringotomy provides middle ear ventilation of sufficient duration for intermediate-term HBO. It compares well with tympanostomy tube material cost, is quicker to perform, and may have less otorrhea and persistent perforations than tympanostomy tube placement. Further study with smaller myringotomies is warranted to determine whether the persistent perforation rate could be decreased without also compromising the needed duration of ventilation. Specifically, a 2- × 2mm myringotomy should be attempted because none of the holes this size failed to heal (Table 1). Because thermal myringotomy provides a closer match between
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middle ear ventilation duration and need, it should be considered as a treatment option in this population. We thank Drs Merrit Davis, Ellen Duncan, and Richard Heimbach for the kind referral of their patients. We also thank Dr Susan Marenda for her assistance in patient accrual, Dr Thomas J. Prihoda (PhD, statistics) for statistical guidance, and Xomed (Jacksonville, FL) for providing the Thermo Tip 2 devices at no charge. REFERENCES 1. Meinje NG. Hyperbaric oxygen and its clinical value. Springfield: Charles C Thomas Publishers; 1970. p. 3-93. 2. Fernau JL, Hirsch BE, Derkay C, et al. Hyperbaric oxygen therapy: effect on middle ear and eustachian tube function. Laryngoscope 1992;102:48-52. 3. Tos M, Bonding P, Poulsen GP. Tympanosclerosis of the drum in secretory otitis after insertion of grommets. A prospective comparative study. J Laryngol Otol 1983;97:489-96. 4. Maw AR. Development of tympanosclerosis in children with otitis media with effusion and ventilating tubes. J Laryngol Otol 1991;105:614-7. 5. Marks RG. Designing a research project, the basics of biomedical research methodology. New York: Van Nostrand Reinhold; 1982. p. 130-2. 6. Soderberg S, Hellstrom S, Stenfors LE. Tympanic membrane changes resulting from different methods of transmyringeal middle ear ventilation. Am J Otolaryngol 1985;6:237-40. 7. Goode RL, Schulz W. Heat myringotomy for the treatment of serous otitis media. Otolaryngol Head Neck Surg 1982;90:764-6. 8. Saito H, Miyamoto D, Kishimoto S, et al. Burn perforation as a method of middle ear ventilation. Arch Otolaryngol 1978;104: 79-81. 9. Ruckley RW, Blair RL. Thermal myringotomy (an alternative to grommet insertion in childhood secretory otitis media?). J Laryngol Otol 1988;102:125-8. 10. Clements KS, Vrabec JT, Mader JT. Complications of tympanostomy tubes inserted for facilitation of hyperbaric oxygen therapy. Arch Otolaryngol Head Neck Surg 1998;124:278-80.
Controversies and Advances in Head and Neck Surgery
This course, presented by the Cleveland Clinic Foundation Department of Otolaryngology, will be held October 29-30, 1999, at the Marriott Key Center, Cleveland, OH. For further information, contact the Department of Continuing Medical Education, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland OH 44195; phone, 216444-5696 or 800-762-8173; fax, 216-445-9406.