This information is suitable for trainee surgeons and GPs.
Definition
A second look combined approach tympanoplasty is the operation that is undertaken between six and eighteen months following a first look intact wall mastoid exploration
Indications
Following a first look intact wall mastoid exploration (combined approach tympanoplasty), usually for cholesteatoma, but occasionally for granulation disease.
Anaesthetic
Generally it is appropriate to use a general anaesthetic, although it may also be performed under local anaesthetic. This will depend on whether a stab incision or a full re-exploration via the first incision is used.
Technique
There are two possible techniques. Either re-opening the old incision used at the first operation or in preference a small 1-2 cm stab incision inside the previous scar in the post aural sulcus in order to permit a minimally invasive endoscopic procedure.
Assuming a minimally invasive procedure, a 1-2 cm incision is made superiorly to the ear canal, but in the post aural sulcus. The incision is deepened to the mastoid bone and the mastoid cavity is entered. On occasions there can be new bone growth over the mastoid bowel, which may require drilling away in order to allow entry.
Once the cavity is opened there may be good aeration with a few mucosal folds, which can be easily broken down. Alternatively there may be a range from that status to a cavity, which is completed filled with gelatinous scar tissue. Fortunately this can almost invariably be aspirated with no difficulty in order to reveal the whole of the mastoid cavity region, including the attic region.
Microscopic examination of those areas that can be seen with the microscope is carried out to search for any residual and/or recurrent cholesteatoma. Following this an endoscopic examination is performed using a 0 degree and a 30 degree 1.9/2.7 mm diameter otoscope (11 cm long) either by eye or via camera and screen. The particular areas of interest are the attic region, the tip of the mastoid and the sinodural angle, which may not have been seen by microscopic examination. The posterior tympanotomy is also opened so that the mesotympanum can be examined through it and attic regions again looking for recurrence or residual disease.
Following this an anterior tympanotomy is performed either though the stab incision or per-meatally. A tympanomeatal flap is raised and the mesotympanic area is examined with particular reference to the retrotympanum, hypotympanum and protympanum, i.e towards the eustachian tube. This, of necessity, is carried out using a 0 degree or 30 degree 1.9 or 2.7 mm, 11 cm long endoscope. Occasionally it is necessary to employ a 70 degree telescope. The purpose of endoscopy is to examine all hidden areas for recurrence or residual cholesteatoma. It is also possible to use a 1.9 mm endoscope if access is difficult, however the field is poorer. Once any residual disease is found and removed, reconstruction of the ossicular chain is carried out provided it is not advisable to wait and carry out a 3rd look procedure.
The reconstruction can be observed after the tympanic membrane has been replaced via an endoscopic view through the posterior tympanotomy via the stab incision.
At any stage, if extensive recurrence is found that cannot be resected endoscopically, the old incision is re-opened in order to carry out a full formal revision combined approach tympanoplasty and/or to change it into a mastoid cavity.
Length of operation
Thirty minutes to one and a half hours.
Time in hospital
Day case or overnight. No drains are required assuming a stab incision. Similarly, no head bandages are required. If the old incision is re-opened then the normal head bandages are applied post operatively.
Limitations
The limitations to the technique of minimally invasive second look combined approach tympanoplasty are if there is extensive recurrence. However, exposure of the facial nerve, a previously discovered fistula or new bone growth does not preclude the technique.
Risks and Complications
The risk of this surgery are as for all ear surgery and include total hearing loss, dizziness, tinnitus, facial paralysis, loss of taste of the tongue and the need for further exploration due to the possibility of recurrence or residual disease being found. Due awareness must be taken of the fact that heat from the light from the endoscope can potentially cause damage if left in one particular position too long. Also, with the 30 degree or 70 degree scopes, assuming an intact stapes, there is a potential for ossicular damage due to accidentally impinging onto the stapes. Thermal damage to the facial nerve must be a point of particular awareness to the surgeon, although it is extremely improbable if due care is taken.
Outcome/prognosis
The prognosis is extremely good where there is simply residual disease (5-15%), i.e a small pearl of cholesteatoma. For the remaining 10-15% in whom there is a recurrence, a third look operation is likely to be necessary.
Alternative treatments
Alternative treatments include a complete open re-exploration, but still using an intact wall procedure. Alternatively conversion to a mastoid cavity with or without obliteration may be preferred.
