PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 23 no. 1 January –June 2008
PhiliPPine Journal of otolaryngology-head and neck Surgery 27
SURGICAL INNOVATIONS AND INSTRUMENTATION
ABSTRACT
Objective: To develop a simple, portable, inexpensive model for otolaryngology trainees to
practice on and develop skills required for myringotomy and tympanostomy tube insertion.
Materials and Methods: Recycled plastic egg crate, a 3-cc plastic syringe, micropore™ tape and
modeling clay were used to create a model to practice myringotomy and tympanostomy tube
insertion utilizing tubes fashioned from a recycled 18 guage intravenous catheter.
Result: The model myringotomy practice set is an inexpensive, simple do-it-yourself device
made of locally available, mostly recycled materials.
Keywords: myringotomy practice set, myringotomy, middle ear ventilation, tympanostomy,
tympanostomy tube insertion, instrumentation
MyRingOTOMy with or without tympanostomy tube insertion is a common ambulatory
procedure performed by otorhinolaryngologists. It is usually indicated for otitis media with
effusion, and other specific manifestations of eustachian tube dysfunction and middle ear
pathology.
Although the procedure is relatively fast, safe and easy, it still requires appropriate microsurgical
skills. Unlike temporal bone dissection for learning mastoidectomy, training for myringotomy is
difficult if not impossible to do in locally-available cadavers due to hardened and desiccated
tissues. Models for teaching myringotomy have been developed but are usually expensive and
not readily available especially in our local setting. Otorhinolaryngology residents are usually
introduced to myringotomy by observation followed by practice on actual patients, with all the
attendant risks and complications associated with the learning curve. We aimed to develop a
simple, portable, inexpensive model for trainees to practice with and develop the skills required
for myringotomy and tympanostomy tube insertion without compromising patient safety. The
Model Myringotomy Practice Set:
A do-it-yourself and inexpensive alternative
Melita Jesusa Suga Tuaño Uy, MD
Norberto V. Martinez, MD
Department of Otorhinolaryngology
- Head and Neck Surgery
University of Santo Tomas Hospital
España, Manila
Correspondence: Melita Jesusa Suga Tuaño Uy, MD
Department of Otorhinolaryngology
-Head and Neck Surgery
University of Santo Tomas Hospital
España, Manila 1001
Phone : (632) 731-3001 local 2411
Philippines
E-mail address: suga_7200@yahoo.com
Reprints will not be available from the author.
No funding support was received for this study. The authors
signed a disclosure that they have no proprietary or financial
interest with any organization that may have a direct interest
in the subject matter of this manuscript, or in any product
used or cited in this study.
Presented at the Instrument Design Contest (2nd place)
Philippine Society of Otolaryngology Head and Neck Surgery
50th Annual Convention, EDSA Shangri-la Plaza Hotel,
Mandaluyong City, December 2, 2006.
Philipp J Otolaryngol Head Neck Surg 2007; 22 (1,2): 27-30 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc.
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 23 no. 1 January –June 2008
SURGICAL INNOVATIONS AND INSTRUMENTATION
28 PhiliPPine Journal of otolaryngology-head and neck Surgery
materials for this model are readily available and are inexpensive.
MATERiALS AnD METHODS
Materials
1. Egg crates, plastic
2. Modeling clay
3. 3-cc plastic syringe (Terumo, Japan) for the External Auditory
Canal
4. Micropore™ Surgical Tape (3M™, St. Paul, MN, U.S.A.) or paraffin,
cellophane or latex gloves for the Tympanic Membrane
5. Rubber bands (to secure the tympanic membrane)
6. Intravenous Catheter 18 Gauge (Introcan-W, B.Braun Laboratories,
Brazil) for making tympanostomy tubes, or recycled commercially
available Tympanostomy tubes
Procedure
The syringe was cut into pieces approximately 2.5 cm long, and one
end of each piece was beveled at around 40 degrees as shown in Figure
1. This beveled syringe would correspond to the external auditory
canal.
The beveled end of each tube was wrapped with micropore™ tape
to simulate a tympanic membrane (Figure 2). Alternatively, paraffin,
cellophane or latex gloves could be used and secured with a rubber
band. The rest of the tube could also be wrapped with paper or
aluminum foil to darken the simulated External Auditory Canal.
A moderate amount of molding clay was placed in each egg crate
(Figure 3) and a depression was made to approximate the middle ear
cavity, with the orifice the size of the tube. Water could be placed in this
depression to simulate middle ear fluid.
The beveled end of each tube was then sealed in the clay, orienting
each in a manner similar to the anatomical orientation of a patient
positioned in sitting or supine position for a myringotomy (Figure 4).
Tympanostomy tubes could be made out of gauge 18 IV cannulae
cut into 2-mm long tubes with the ends heated to create flanges
as previously described1. The model was ready to use for practice
myringotomy and tympanostomy tube insertion. Suctioning of the
fluid could also be practiced (Figures 5 to 9).
Material 1. Egg crates, plastic
Material 2. Modeling clay
Material 3. 3-cc plastic syringe
(Terumo, Japan) for the External Audi-
tory Canal
Material 4. Micropore™ Surgical Tape
(3M™, St. Paul, MN, U.S.A.) or paraffin,
cellophane or latex gloves for the
Tympanic Membrane
Material 5. Rubber bands (to secure
the tympanic membrane)
Material 6. Intravenous Catheter 18
Gauge (Introcan-W, B.Braun Laborato-
ries, Brazil) for making tympanostomy
tubes, or recycled commercially avail-
able Tympanostomy tubes
Table 1. Cost of production of the model myringotomy practice set
Grade of Impairment Corresponding audiometric ISO
value (Average of 500, 1000
and 2000 Hz)
Plastic egg crate
3-cc Syringe
Micropore tape
Modeling Clay
Intravenous Catheter
Rubber bands and paper
Total
Recycled
Recycled ( PhP 5.00 if bought)
Used (PhP 40.00 if bought)
Recycled (PhP 20.00 if bought)
Recycled (PhP 36.50 if bought)
Recycled
(PhP 101.50 if bought)
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 23 no. 1 January –June 2008
SURGICAL INNOVATIONS AND INSTRUMENTATION
PhiliPPine Journal of otolaryngology-head and neck Surgery 29
Figure 1. beveled syringe
Figure 2. beveled syringe wrapped
with micropore
Figure 3. egg crate with modeling clay
Figure 4. tube in clay
Figure 5. tube in crate
Figure 5. practice myringotomy
Figure 6A. model TM made out of
micropore tape
Figure 6B. Brown colored fluid
behind model TM
Figure 7. Myringotomy done on
anteroinferior
Figure 8. suction of fluid
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 23 no. 1 January –June 2008
SURGICAL INNOVATIONS AND INSTRUMENTATION
30 PhiliPPine Journal of otolaryngology-head and neck Surgery
this paper tried to emulate these dimensions of the external ear by
cutting the 3cc syringe to 2.5 cm to approximate the length of the
external auditory canal and beveling one end to mimic the tympanic
membrane orientation. The 3-cc syringe had a diameter of 9 mm
and approximated the dimensions of the tympanic membrane of an
adult. The materials used at the beveled end could be interchanged
to experience different textures for one practice on. In our experience,
Micropore™ tape seemed to best mimic the thickness and resistance
of the tympanic membrane when punctured. Markers could be placed
on the micropore™ prior to the myringotomy exercise to indicate the
proper orientation of the tympanic membrane and the location of the
malleus. After the procedure, trainees could check the accuracy of the
incision based on the markers. Fluid could be placed in the depression
in the modeling clay to practice suctioning fluids from the middle ear.
The color and viscosity could be modified using dyes and thickeners to
mimic various fluids in middle ear diseases. Gentian violet could also
be used to practice and simulate administration of local anesthesia.
Avoidance of the ear canal wall could be practiced by placing dye on
the myringotomy knife and making sure the dye was not transferred to
the walls. Smaller tubes could be used to simulate pediatric ears.
Our device was very economical as most materials were readily
available (or could be purchased at minimal cost) compared with
commercially available mannequins and models (Table 1) with prices
ranging from USD 65.006 to 950.00.7
DiSCUSSiOn
Myringotomy is a common procedure for otorhinolaryngologists.
In cooperative teenagers and adults, this can be done under local
anesthesia in a clinic setting. In children, general anesthesia is usually
required for tympanostomy tube insertion.2 Although this is usually
a straightforward procedure, difficulties during the process may be
encountered. Caution must be exercised to avoid traumatizing the
anterior canal wall to avoid bleeding and pain. Creation of a too-
large myringotomy might cause the tympanostomy tube to fall into
the middle ear. Additional difficulty is encountered when performing
myringotomy on a very small ear canal. These complexities may be
avoided or minimized by the experience and skills of the surgeon.
Trainees are expected to perform such procedures but the lack of
materials and expensive cost of commercially available models for
teaching myringotomy hamper acquisition of skills before practice on
actual patients, potentially compromising patient safety.
Other models have been developed to meet the need for practicing
surgical skills in myringotomy.3,4 Some use a mannequin ear to
simulate the external ear canal These models either use materials that
are not readily available and expensive especially in our setting. Our
proposed model was basically an inexpensive system made out of
readily available materials. One could easily construct his or her own
myringotomy practice set by using the aforementioned materials and
procedure.
The external auditory meatus or canal is composed of the lateral
cartilaginous and medial osseous portions. It is approximately 2.5
cm from the conchal cartilage to the tympanic membrane.5 The
tympanic membrane is approximately 8 mm wide, 9 to 10 mm high
and 0.1 mm thick. Its inferior pole is oriented more medially than its
superior pole by approximately 40 degrees.5 The model described in
Figure 9A. myringotomy tube
in place
Figure 9B. placement of myrin-
gotomy tube
REFEREnCES
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1997. p.1236-1245
3 Owa AO and Farell RW. Simple model for teaching myringotomy and aural ventilation
tube insertion. J Laryngol Otol. 1998 Jul 112(7): 642-3
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teeth.asp#GPI225
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http://www.buyamag.com/index.htm