Lasers Med Sci 1999, 14:62–66 © 1999 Springer-Verlag London Limited
Laser Myringotomy (L-Myringotomy) and Ventilating Tubes: A Preliminary Comparative Study M. Englender1, E. Somech2 and M. Harell1 Departments of 1Otolaryngology and 2Pediatrics, Edith Wolfson Medical Centre, Holon, Israel
Abstract. A prospective comparative study was done to assess the validity of laser myringotomy (L-myringotomy) when compared to the insertion of ventilating tubes (VT). In 23 children with chronic otitis media with e#usion, a VT was inserted in the left ear while a laser myringotomy was performed in the right ear by using the CO2 Sharplan 1030 laser. After a six month follow-up conducted during the winter months, the results with the laser myringotomy were equal to those in the left ear with the VT. During the follow-up period, three ears required additional laser myringotomy either for early closure or because of otitis media and the accumulation of e#usion in the middle ear cavity. Nevertheless, the use of laser has the advantage that there is no foreign body in the ear, the tympanic membrane is closed after four to seven weeks, and since the procedure is very short, the time for anaesthesia is minimal. Keywords: Laser myringotomy; Otitis media with e#usion; Tympanic membrane
INTRODUCTION Myringotomy with insertion of ventilating tubes (VT) to treat children with chronic otitis media with e#usion is the most frequent minor surgical procedure in the USA and probably in most of the western countries [1]. Since ventilating tubes are so frequently used, care must be taken to avoid unnecessary complications deriving from the surgical manipulation and the consequences of the longstanding permanence of the VT in the tympanic membrane [2,3]. The time needed for aeration of the middle ear cavity in patients with middle ear e#usion has still to be determined. Armstrong [4] suggests that two to three weeks are sufficient. Insertion of a VT is not a completely harmless procedure [5]; it requires manipulation in the external auditory canal and tympanic membrane. Usually, VTs are extruded spontaneously after several months or may be rejected even a few hours or days following insertion. The mean duration of the VTs until they are extruded was 21118 days [6]. A longstanding VT (usually more than 12 months) should be removed and often it has to be done under general anaesthesia. Until Correspondence to: Moshe Englender, MD, Department of Otolaryngology, Edith Wolfson Medical Centre, Holon 58100, Israel. Fax: +972 3 647 1327.
rejection occurs, water should be avoided because of the open middle ear cavity and possible infection [7,8]. Rejection occurs when the ventilating tube is recognised as a foreign body [9] and quite often this recognition is also the cause of infection and otorrhoea requiring removal of the VT. Thus, alternative ways have been investigated in order to avoid the disadvantages associated with tympanostomy tubes. Wilpizeski [10] and Goode [11] were among the first to use the CO2 laser for myringotomy, pointing out the advantages of the atraumatic procedure when compared to other techniques to treat secretory otitis media with e#usion. Perkins [12] shares this opinion, but criticises the cost and technical problems associated with the use of the laser equipment. In recent years, the use of CO2 laser in otolaryngology has spread and become more accessible to most ENT surgeons. It has many advantages over other surgical techniques to treat children with secretory otitis media. By using the laser, no instrumentation is needed in the ear, it is a non-touch technique in which a laser beam perforates the tympanic membrane, so the time required for surgery is less. There is no foreign body in the ear that might cause tissue reaction, infection, or fall into the middle ear cavity (as might happen with ventilating tubes). The use of the laser keeps
Comparison of Laser Myringotomy and Ventilating Tubes
the tympanic membrane open, and the middle ear cavity ventilated. Once the perforation is closed, there is no need to keep the child away from water, which is of great concern for parents and physicians particularly during the summer time. Thus, laser myringotomy (L-myringotomy) o#ers a convenient and safe method to ventilate and drain the middle ear cavity, and in the near future, it might become simple enough to be performed as an o$ce procedure by the otolaryngologist and paediatrician. Since water and other liquids are the best medium to use in absorbing the CO2 laser energy, it is obvious that in acute and secretory otitis media, using a low voltage focused or slightly defocused laser beam on the tympanic membrane, will cause no damage to the middle ear or other structures [13], thus making L-myringotomy a safe procedure. In this study, we examined the e$cacy and safety of L-myringotomy only in children with otitis media with e#usion and compared the results to the insertion of a ventilating tube in the same child. Both ears were compared with regard to otorrhoea and hearing improvement at the end of the follow-up period.
MATERIALS AND METHODS The study was conducted at the outpatient ENT and paediatric clinics of the E. Wolfson Medical Center in Holon, Israel. All the children were operated on during the months of November/December and were followed up until May/June (winter season in Israel). A total of 23 children, 14 males and 9 females, aged 2 years to 7 years (mean 3.4 years) were included in the study after obtaining informed consent from the parents. All the children had recurrent ear infections, they were previously treated with several courses of antibiotics, and had at least one knife myringotomy or a spontaneous perforation of the tympanic membrane because of acute otitis media. They also had a bilateral conductive hearing loss as proven by audiometry, tympanometry, and otoscopy performed by an experienced otolaryngologist (M.E. and M.H.). Children with unilateral ear infections or requiring other surgeries, such as adenoidectomy and/or tonsillectomy were excluded. Children with facial anomalies, as well as
63
patients with serious underlying diseases were not enrolled.
Surgical Procedure Under general anaesthesia, a ventilating tube was inserted in all children into the left ear, whereas a laser myringotomy was always done in the right ear by using the Sharplan CO2 laser connected to a surgical microscope and an acuspot that allows changing the spot size to the diameter required for the myringotomy [14]. The diameter of the perforation on the tympanic membrane varied between 1.6 mm to 2.6 mm (average 1.8 mm) as measured by a reticule mounted into the microscope eyepiece that was previously calibrated. Considering an average diameter of 1.8 mm of the laser beam and an average power setting of 11 W the power density was of 4.3 W/mm2. Laser myringotomy is a non-invasive technique in which a circumscribed portion of the eardrum is ablated by the laser beam, which hits the tympanic membrane through a blackened ear speculum. By using the operating microscope with a 300 mm lens, the laser is put on a defocused beam CW mode with a power setting of 10–12 W (continuous wave mode) with pulse duration of 0.1–0.2 s thus performing a tympanic membrane perforation with a diameter of 1.6–2.6 mm. Sometimes with a thickened tympanic membrane more than one pulse was needed. Another method to obtain the same size of perforation was by using the superpulse mode 1–2 W in several single pulses and thus creating an opening with the desired diameter (peak power density approximately 40 W/mm2). Thus, by using the superpulse mode, one obtains high energy in a very short period of time with excellent ablation of tissue and no char. All ventilating tubes, as well as the L-myringotomies, were in the anterior– inferior quadrant of the tympanic membrane. The size of the laser perforation, in either way used, can be regulated, thereby controlling the time the tympanic membrane is open and the middle ear ventilated [15]. In this study, all the L-myringotomies were circular. Parents were told to report on any signs of ear infection or discharge, and they had free access to the clinic whenever a problem occurred. Patients with postoperative otorrhoea were treated with a 10-day course of antibiotics, but were not excluded from the study.
64
M. Englender et al.
Statistical Analysis The percentage otorrhoea was compared using chi square test with the Yets correction. Hearing improvement, measured by air–bone gap, was tested using the paired t-test, both to show hearing improvement within each ear and to compare the hearing improvement between the two ears. Since both surgical procedures were statistically equivalent, we performed a power analysis on a sample of these 23 cases. The power analysis indicated 90% power to detect di#erences as small as hearing improvement of 5 decibels and 32% di#erence in the presence of otorrhoea. Regression analysis of closure duration of the perforated tympanic membrane points out that each additional 0.1 mm in the diameter of the L-myringotomy prolongs the closure duration in 1.3 days (p=0.009).
RESULTS All the children were followed-up through the entire winter months period (November/ December to May/June) at the paediatric ENT out-patient clinic. Follow-up visits were one week, four weeks, two months, three months, and six months after surgery. On their last follow-up visit, audiometry and tympanometry were done. Recordings were obtained with regard to otorrhoea, any hearing problems, or to other symptoms that might be related to otitis media. The duration of patency of the right ears with the L-myringotomy was of significant consideration in our study and it varied between 32 and 45 days (average 37.4 days) (Table 1). There was no perforation at the last follow-up visit at six months after L-myringotomy. Three ears required additional Table 1. Duration of patency of ears with L-myringotomy No. of ears
8 7 6 1 1 23
Size of perforation (mm)
Mean duration (days)
1.6 1.8 2.0 2.4 2.6
32 39 41 45 40
Mean=1.8
Mean=37.4
Fig. 1.
Hearing improvement following surgery.
L-myringotomy because of early closure of the tympanic membrane or re-infection after healing. None of the VTs were extruded during the follow-up. Of the 23 patients, six had at least one episode of otorrhoea. In four (17.4%), it was from the left ear with the ventilating tube, and in two (8.7%), otorrhoea was from the right ear with the L-myringotomy (p=0.661, not statistically significant). The mean air–bone gap in the left ears before surgery was 26.5 (SD=10.5) decibels. It was 5.2 (SD=5.3) decibels at the end of the study with the tubes still in place. The mean air–bone gap in the right ears before the L-myringotomy was 28.3 (SD=8.9) decibels and 6.0 (SD=9.2) decibels after six months (Fig. 1). Overall hearing improvement was statistically significant (for the left p
Laser Myringotomy (L-Myringotomy) and Ventilating Tubes: A Preliminary Comparative Study M. Englender1, E. Somech2 and M. Harell1 Departments of 1Otolaryngology and 2Pediatrics, Edith Wolfson Medical Centre, Holon, Israel
Abstract. A prospective comparative study was done to assess the validity of laser myringotomy (L-myringotomy) when compared to the insertion of ventilating tubes (VT). In 23 children with chronic otitis media with e#usion, a VT was inserted in the left ear while a laser myringotomy was performed in the right ear by using the CO2 Sharplan 1030 laser. After a six month follow-up conducted during the winter months, the results with the laser myringotomy were equal to those in the left ear with the VT. During the follow-up period, three ears required additional laser myringotomy either for early closure or because of otitis media and the accumulation of e#usion in the middle ear cavity. Nevertheless, the use of laser has the advantage that there is no foreign body in the ear, the tympanic membrane is closed after four to seven weeks, and since the procedure is very short, the time for anaesthesia is minimal. Keywords: Laser myringotomy; Otitis media with e#usion; Tympanic membrane
INTRODUCTION Myringotomy with insertion of ventilating tubes (VT) to treat children with chronic otitis media with e#usion is the most frequent minor surgical procedure in the USA and probably in most of the western countries [1]. Since ventilating tubes are so frequently used, care must be taken to avoid unnecessary complications deriving from the surgical manipulation and the consequences of the longstanding permanence of the VT in the tympanic membrane [2,3]. The time needed for aeration of the middle ear cavity in patients with middle ear e#usion has still to be determined. Armstrong [4] suggests that two to three weeks are sufficient. Insertion of a VT is not a completely harmless procedure [5]; it requires manipulation in the external auditory canal and tympanic membrane. Usually, VTs are extruded spontaneously after several months or may be rejected even a few hours or days following insertion. The mean duration of the VTs until they are extruded was 21118 days [6]. A longstanding VT (usually more than 12 months) should be removed and often it has to be done under general anaesthesia. Until Correspondence to: Moshe Englender, MD, Department of Otolaryngology, Edith Wolfson Medical Centre, Holon 58100, Israel. Fax: +972 3 647 1327.
rejection occurs, water should be avoided because of the open middle ear cavity and possible infection [7,8]. Rejection occurs when the ventilating tube is recognised as a foreign body [9] and quite often this recognition is also the cause of infection and otorrhoea requiring removal of the VT. Thus, alternative ways have been investigated in order to avoid the disadvantages associated with tympanostomy tubes. Wilpizeski [10] and Goode [11] were among the first to use the CO2 laser for myringotomy, pointing out the advantages of the atraumatic procedure when compared to other techniques to treat secretory otitis media with e#usion. Perkins [12] shares this opinion, but criticises the cost and technical problems associated with the use of the laser equipment. In recent years, the use of CO2 laser in otolaryngology has spread and become more accessible to most ENT surgeons. It has many advantages over other surgical techniques to treat children with secretory otitis media. By using the laser, no instrumentation is needed in the ear, it is a non-touch technique in which a laser beam perforates the tympanic membrane, so the time required for surgery is less. There is no foreign body in the ear that might cause tissue reaction, infection, or fall into the middle ear cavity (as might happen with ventilating tubes). The use of the laser keeps
Comparison of Laser Myringotomy and Ventilating Tubes
the tympanic membrane open, and the middle ear cavity ventilated. Once the perforation is closed, there is no need to keep the child away from water, which is of great concern for parents and physicians particularly during the summer time. Thus, laser myringotomy (L-myringotomy) o#ers a convenient and safe method to ventilate and drain the middle ear cavity, and in the near future, it might become simple enough to be performed as an o$ce procedure by the otolaryngologist and paediatrician. Since water and other liquids are the best medium to use in absorbing the CO2 laser energy, it is obvious that in acute and secretory otitis media, using a low voltage focused or slightly defocused laser beam on the tympanic membrane, will cause no damage to the middle ear or other structures [13], thus making L-myringotomy a safe procedure. In this study, we examined the e$cacy and safety of L-myringotomy only in children with otitis media with e#usion and compared the results to the insertion of a ventilating tube in the same child. Both ears were compared with regard to otorrhoea and hearing improvement at the end of the follow-up period.
MATERIALS AND METHODS The study was conducted at the outpatient ENT and paediatric clinics of the E. Wolfson Medical Center in Holon, Israel. All the children were operated on during the months of November/December and were followed up until May/June (winter season in Israel). A total of 23 children, 14 males and 9 females, aged 2 years to 7 years (mean 3.4 years) were included in the study after obtaining informed consent from the parents. All the children had recurrent ear infections, they were previously treated with several courses of antibiotics, and had at least one knife myringotomy or a spontaneous perforation of the tympanic membrane because of acute otitis media. They also had a bilateral conductive hearing loss as proven by audiometry, tympanometry, and otoscopy performed by an experienced otolaryngologist (M.E. and M.H.). Children with unilateral ear infections or requiring other surgeries, such as adenoidectomy and/or tonsillectomy were excluded. Children with facial anomalies, as well as
63
patients with serious underlying diseases were not enrolled.
Surgical Procedure Under general anaesthesia, a ventilating tube was inserted in all children into the left ear, whereas a laser myringotomy was always done in the right ear by using the Sharplan CO2 laser connected to a surgical microscope and an acuspot that allows changing the spot size to the diameter required for the myringotomy [14]. The diameter of the perforation on the tympanic membrane varied between 1.6 mm to 2.6 mm (average 1.8 mm) as measured by a reticule mounted into the microscope eyepiece that was previously calibrated. Considering an average diameter of 1.8 mm of the laser beam and an average power setting of 11 W the power density was of 4.3 W/mm2. Laser myringotomy is a non-invasive technique in which a circumscribed portion of the eardrum is ablated by the laser beam, which hits the tympanic membrane through a blackened ear speculum. By using the operating microscope with a 300 mm lens, the laser is put on a defocused beam CW mode with a power setting of 10–12 W (continuous wave mode) with pulse duration of 0.1–0.2 s thus performing a tympanic membrane perforation with a diameter of 1.6–2.6 mm. Sometimes with a thickened tympanic membrane more than one pulse was needed. Another method to obtain the same size of perforation was by using the superpulse mode 1–2 W in several single pulses and thus creating an opening with the desired diameter (peak power density approximately 40 W/mm2). Thus, by using the superpulse mode, one obtains high energy in a very short period of time with excellent ablation of tissue and no char. All ventilating tubes, as well as the L-myringotomies, were in the anterior– inferior quadrant of the tympanic membrane. The size of the laser perforation, in either way used, can be regulated, thereby controlling the time the tympanic membrane is open and the middle ear ventilated [15]. In this study, all the L-myringotomies were circular. Parents were told to report on any signs of ear infection or discharge, and they had free access to the clinic whenever a problem occurred. Patients with postoperative otorrhoea were treated with a 10-day course of antibiotics, but were not excluded from the study.
64
M. Englender et al.
Statistical Analysis The percentage otorrhoea was compared using chi square test with the Yets correction. Hearing improvement, measured by air–bone gap, was tested using the paired t-test, both to show hearing improvement within each ear and to compare the hearing improvement between the two ears. Since both surgical procedures were statistically equivalent, we performed a power analysis on a sample of these 23 cases. The power analysis indicated 90% power to detect di#erences as small as hearing improvement of 5 decibels and 32% di#erence in the presence of otorrhoea. Regression analysis of closure duration of the perforated tympanic membrane points out that each additional 0.1 mm in the diameter of the L-myringotomy prolongs the closure duration in 1.3 days (p=0.009).
RESULTS All the children were followed-up through the entire winter months period (November/ December to May/June) at the paediatric ENT out-patient clinic. Follow-up visits were one week, four weeks, two months, three months, and six months after surgery. On their last follow-up visit, audiometry and tympanometry were done. Recordings were obtained with regard to otorrhoea, any hearing problems, or to other symptoms that might be related to otitis media. The duration of patency of the right ears with the L-myringotomy was of significant consideration in our study and it varied between 32 and 45 days (average 37.4 days) (Table 1). There was no perforation at the last follow-up visit at six months after L-myringotomy. Three ears required additional Table 1. Duration of patency of ears with L-myringotomy No. of ears
8 7 6 1 1 23
Size of perforation (mm)
Mean duration (days)
1.6 1.8 2.0 2.4 2.6
32 39 41 45 40
Mean=1.8
Mean=37.4
Fig. 1.
Hearing improvement following surgery.
L-myringotomy because of early closure of the tympanic membrane or re-infection after healing. None of the VTs were extruded during the follow-up. Of the 23 patients, six had at least one episode of otorrhoea. In four (17.4%), it was from the left ear with the ventilating tube, and in two (8.7%), otorrhoea was from the right ear with the L-myringotomy (p=0.661, not statistically significant). The mean air–bone gap in the left ears before surgery was 26.5 (SD=10.5) decibels. It was 5.2 (SD=5.3) decibels at the end of the study with the tubes still in place. The mean air–bone gap in the right ears before the L-myringotomy was 28.3 (SD=8.9) decibels and 6.0 (SD=9.2) decibels after six months (Fig. 1). Overall hearing improvement was statistically significant (for the left p
