Cholesteatoma arising from the petrous apex is a rarity. It is still difficult to make an early diagnosis of this lesion because of the anatomical structure of the petrous apex. In the present study we reviewed our 10 cases of cholesteatoma of the petrous apex, and discussed mainly on the surgical approaches to this lesion. Patients presenting with limited preoperative deficits have challenged the surgeon to design the surgical approach in order to preserve functions such as hearing and facial nerve function. Although the design of the surgical approach should be dependent on the preoperative hearing and facial nerve function, we emphasized that the middle cranial fossa approach is appropriate for the petrous apex lesion. In addition, we discussed the possibility of hearing preservation by the partial labyrinthectomy with the review of the literature.
The efficacy of the preoperative 1mm-slice CT for evaluating the condition of the ossicular chain and the facial cannl was assessed. CT findings were compared with the operative findings of middle ears in 120 cases of chronic otitis media or cholesteatoma that underwent tympanoplasty. The riliability of lmm-slice CT in detecting any defect of the ossicular chain was much superior to those of 2mm-slice CT previously reported, and the difference between them is essential for preoperative information. On the other hand, thinner slice than 1mm may be unnecessary, especially in routine use.
We reported the outcome of bilateral middle ear surgery in 77 patients (154 ears) with chronic ear diseases between 1986 and 1998. Concerning the development of mastoid pneumatization, 154 ears with bilateral ear surgery were compared with other 168 ears received unilateral ear surgery. In cases with bilateral ear surgery, sclerosis of mastoid pneumatization was more often found compared with cases received unilateral ear surgery significantly. The hearing result was successful when the postoperative hearing level satisfied with at least one of three conditions as follows: 1) air-bone gap less than 20 dB, 2) hearing level above 40 dB, or 3) hearing gain more than 15dB. Bilateral success rate was 73.3%, unilateral success rate was 21.3% and bilateral unsuccess rate was 5.3%. The problems of surgery and counterplans on the ear with poorer hearing, especially only hearing ear, and on the case with bilateral cholesteatoma were discussed.
The first patient was a 48-year-old female with chronic otitis media of the left ear. The second patient was a 37-year-old male with cholesteatoma in the pars flaccida of the left ear. These two patients were operated by “canal wall up” method. Mastoidectomy revealed a mastoid cyst, filling in the mastoid cavity, and occipital bony defects in the mastoid area. Bony destruction of the 2nd patient was so severe that the sigmoid sinus was clearly observed. The aditus of both patients was completely obliterated by the cyst wall and a cholesterol granuloma. These obstruction of the air ventilation in the middle ear space at the aditus were thought to play an important role in the ctiology of the cyst. The mastoid cyst of the 1st patient was removed by the en block mothod, but that of the 2nd patient was resected piece by piece. The membranous blockage at the aditus was removed, and bony defect was reconstructed with auricular cartilage. After the removal of the cyst, the epiytmpanic cavity and the mastoid cavity were obliterated by bony pate to reduce the overload of the tubal function. Post-operatively, the hearing was improved and rapid epithelization of the tympanic menbrane was observed.
A 8-year-old girl of CHARGE association with a moderate mixed hearing loss was reported. Her temporal bone CT and MRI showed ossicular chain deformity, Mondini type malfomation of the cochlea, and the absent three semicircular canals with dilatated vestible. The hearing loss showed mixed type due to congenital middle ear anomaly. The patient underwent middle ear surgery in the left ear. A monopodal stapes attached the fallopian canal, the footplate was missing, and the oval window was covered by loose connevtive tissue. Post operative hearing improved by 27. 5dB. However, her hearing gain decreased by about 10dB one year after surgery.
A 38-year-old man complained of a hearing loss of the right ear and a swelling of the right temporal bone. The right external auditory canal (EAC) was stenotic because of the swelling of the temporal bone. Despite meatoplasty three times, twice before visiting our hospital and once at our hospital, stenosis of the right EAC and hearing loss of the right ear recurred. During the second operation at our hospital, to prevent stenosis of the EAC, normal bone chips and bone paste on the healthy side were used for meatoplasty. The EAC was opened and hearing was improved and these condition maintained for 5 years after the second operation at our hospital. Use of normal bone chips and bone paste for meatoplasty proved very effective to prevent stenosis of the EAC in the case of fibrous dysplasia of the temporal bone.
The incidence of brain herniation into the mastoid is a rare complication of mastoid surgery. However, we should not overlook the seriousness of the complication and the potential for its prevention. A 6-year-old boy presented with a temporal lobe herniation (meningoencephalocele) originated from mastoid surgery for middle ear cholesteatoma. The herniation might expand into mastoid cavity so slowly that it might have developed without any clinical symptoms such as the cerebrospinal fluid leakage. The herniation had at first been treated by transmastoid approach in the revision tympanoplasty. One and half year after that repir of the tegmen defect, a head trauma by a fall accident brought him reccurence of the temporal herniation by chance. The tegmen defect was too large to close primarily, a middle fossa approach was added to the transmasid approach. A satisfactory technique by using the fascia-bone-fascia graft (sandwich) was also reported. The dura and arachnoid may be easily damaged during mastoidectomy, therefore it is always neccessary to inspect carefully any area of dural exposure.