Preservation of hearing in cholesteatomas with inner ear invasion

Two cases of inner ear destruction by cholesteatoma are presented. There was total demineralization of the cochlea in one and significant vestibular destruction in the other. Eradication and exteriorization of the disease was accomplished with preservation of hearing in both cases. Safe management was enhanced by aggressive infection control and accurate surgical planning aided by current imaging techniques. The factors which protect auditory function in these lesions remain unclear. However, the site and extent of the disease as well as local tissue reaction leading to separation of the inflammatory process from the sensory epithelium appear to play a significant role in preservation of hearing despite the presence of invasive, destructive disease.

Stapes surgery in osteogenesis imperfecta

Between 1968 and 1986 stapes surgery has been performed in the Nijmegen University Department of Otorhinolaryngology in 11 patients (14 ears) with osteogenesis imperfecta. Detailed information about pre- and postoperative hearing levels, findings at surgery, and the follow-up period are presented. In most cases the stapedectomy has been successful.

Perilymphatic fistula in pediatric patients with a preexisting sensorineural loss

A specific group of 28 children (38 ears) with a preexisting sensorineural hearing loss (SNHL) was studied to determine if a perilymphatic fistula (PLF) was the cause of a progression in their hearing loss. A PLF was identified surgically in six of these ears, but there was no evidence of any defect found in 32 ears. The symptoms shared by the cases in which a fistula was found included a traumatic event (including exertion), CT scan evidence of inner ear defects, hearing threshold decreases of 25 to 30 dB, and vertigo or postural instability.

Auditory brain stem response monitoring during middle ear surgery

Conductive hearing loss can be determined in the course of middle ear surgery by sound probe stimulation and simultaneous recording of auditory brain stem responses. Mechanical properties of the ossicular chain, usually judged subjectively by the surgeon's visual and tactile senses, can be quantified objectively. Thus, disarticulation of ossicles can be localized precisely, and fixation of the head of the malleus can be differentiated from stapes fixation. Moreover, the function of the reconstructed ossicular chain or prosthesis may be ascertained.

[Function-saving microsurgery in suboccipital removal of large acoustic neuromas]

Various successful approaches are available for acoustic neurinoma surgery, permitting total tumor removal and preservation of cranial nerve function. In smaller and medium sized tumors excellent results can be achieved with respect to facial and cochlear nerve function using the transtemporal approach. For larger tumors similar results can be achieved by the suboccipital approach. The results of 45 completely removed large acoustic neurinomas all operated upon via the suboccipito-lateral approach with microsurgical techniques and neurophysiological monitoring are presented. The average tumor size, excluding the portion within the internal auditory canal was 3 cm. Anatomical preservation of the VIIth cranial nerve was achieved in nearly all cases. Satisfactory to excellent facial nerve function was preserved in 70% of all cases. Initial hearing was preserved in 29%. However delayed postoperative hearing loss was encountered in 13%. Therefore definite hearing preservation was achieved in 16% of the cases. Intraoperative monitoring, especially of auditory evoked potentials, was very helpful in achieving these functional results.

Cavernous hemangiomas of the internal auditory canal

Cavernous hemangiomas are vascular malformations that are seldom found in the central nervous system. Four cavernous hemangiomas of the internal auditory canal and one of the cerebellopontine angle have been reported previously. We present a series of seven (six of which have never been reported) cavernous hemangiomas limited primarily to the internal auditory canal. Whereas all cases but one had marked unilateral sensorineural hearing loss, only two had preoperative facial nerve dysfunction. There are no specific symptoms or physical or audiometric findings to differentiate cavernous hemangiomas from acoustic neuromas. However, a hemangioma should be suspected when facial paralysis is present in conjunction with a small intracanalicular tumor as demonstrated by computed tomography or magnetic resonance imaging. The former reveals calcium stippling in the lesions, whereas magnetic resonance imaging reveals a high signal intensity on both T1- and T2-weighted images.

Cochlear implant indications

Many centers are investigating the safety and efficacy of cochlear implants in adults and children. In the United States, the Food and Drug Administration (FDA) has monitored these investigations, recently approving two devices for general use in adults. In general, appropriate implant candidates have a bilateral, profound to total sensorineural hearing loss, are unable to benefit from conventional hearing aids, are in good physical and mental health, and have the motivation and patience to complete a rehabilitation program. The patient likely to receive most benefit from a cochlear implant is one who acquires profound deafness after developing verbal language skills and is implanted within a few years of the onset of deafness.

Unilateral sensorineural deafness in children

Heredity, viral infection, and head or acoustic trauma are considered the common etiologies for a unilateral sensorineural deafness in children. The incidence of perilymphatic fistula in a unilateral hearing loss is still unknown. Inner ear-related symptoms in children are scarce, and little diagnostic laboratory testing is available. A definite diagnosis of a perilymphatic fistula can therefore be made only by an exploratory tympanotomy. Four children, ages 5 to 15 years, with a history of a recent and rapidly progressive unilateral sensorineural hearing loss, were explored. Preoperative laboratory data, which included a fistula test, ENG, CT scan of the temporal bones, and an ABR, were all within normal limits. An overt fistula was found in only one of the patients. Only an exploratory tympanotomy can arrest and possibly reverse a unilateral hearing loss or discontinue a middle ear-cranial cavity communication. It is therefore our feeling that, in patients with an appropriate history, the potential benefit outweighs the risk and morbidity of an exploratory tympanotomy.

Otitis media and congenital perilymphatic fistula as a cause of sensorineural hearing loss in children

In all infants and children who have progressive, fluctuating or sudden sensorineural hearing loss, the possibility of a congenital perilymphatic fistula should be considered. Factors determined to be highly suggestive of the presence of a congenital perilymphatic fistula as the cause of sensorineural hearing loss or vertigo, or both, include the following: mixed conductive and sensorineural hearing loss; antecedent sudden physical exertion or barotrauma; congenital deformities of the external ear and head; and abnormal findings on computed tomograms of the temporal bone, especially Mondini-like ear dysplasias. In a series of 37 children who had a congenital perilymphatic fistula treated at the Children's Hospital of Pittsburgh, 28 (76%) had had documented otitis media in the past or a history of middle ear disease. This finding should alert the clinician to the possibility of the presence of a congenital perilymphatic fistula when sensorineural hearing loss develops or progresses during an episode of otitis media. Perilymphatic fistula is caused by either congenital ossicular deformities or abnormalities of the labyrinthine windows or coexistence of both conditions. The likelihood of there being no further deterioration in hearing after surgical repair of a perilymphatic fistula is high. Every infant and child with unexplained hearing loss or disequilibrium or both deserves an attempt to uncover the cause at the earliest possible age.

Multichannel cochlear implantation in a patient with bilateral Mondini deformities

A 31-year-old man with bilateral Mondini dysplasia was successfully implanted with a Nucleus multichannel 22-electrode cochlear prosthesis. To our knowledge, this is the first report of multichannel cochlear implantation in a patient with Mondini dysplasia. The surgical procedure used to insert the device was uncomplicated. Although objective measurements demonstrated only slight improvement in most categories of the Iowa test battery, he has the ability to discriminate pure-tone frequency differences and environmental sounds. Subjectively, he was a satisfied implant user. The surgical feasibility of multichannel implantation in patients with Mondini dysplasia should open the door for improved speech recognition and tonal discrimination in this subset of patients.

Endolymphatic sac surgery in congenital malformations of the inner ear

A retrospective analysis of 40 patients (49 ears) with congenital progressive sensorineural hearing loss who underwent endolymphatic sac surgery was performed. The inner ears were radiographically abnormal in 57% of operated ears. In the remaining cases, subtle malformations beyond the resolving power of radiographic studies were suspected. Early postsurgical hearing loss (defined as a loss greater than 10 dB in three-tone average or greater than 15% in speech discrimination score) was found in 29% of operated ears (14/49). However, only two of these patients lost all of their residual hearing postoperatively (2/49 or 4%). An enlarged endolymphatic sac was noted at surgery in 50% of those with significant postoperative hearing losses. Longer-term stability of hearing was assessed in 22 patients with bilateral inner-ear pathology who underwent surgery on one side only. A comparison of the hearing fate of the operated and nonoperated ears suggested no benefit from the surgical intervention when compared to the natural history of the disease. Based upon this experience, endolymphatic sac surgery for the purpose of hearing stabilization in patients with congenital malformations of the inner ear is no longer recommended.

Perilymphatic fistula in children with preexisting sensorineural hearing loss

Progression of preexisting sensorineural hearing loss (SNHL) in infants and children has been considered an indication for fistula exploration: is this approach warranted? On exploring 36 middle ears in 26 such children, we found a perilymphatic fistula (PLF) in four ears (11%). Although there was radiographic evidence of inner-ear deformity in one half of these children, a definite fistula was found in only four of 18 radiographically abnormal ears explored (22%). Even in the four patients with a history of an "event" that could implicate a fistula such as exertion or barotrauma, a fistula was found in only one. There are a number of possible causes for progression of a preexisting SNHL, and surgical exploration of the middle ear should not be recommended on the basis of progression alone. Instead, exploration for a suspected PLF should be strongly considered when there is also a history of an "event", and/or radiographic evidence of inner-ear abnormalities. Even under these conditions, one should be aware that fistulae are not likely to be found.

Surgical evaluation of candidates for cochlear implants

The customary presentation of surgical procedures to patients in the United States consists of discussions on alternative treatment methods, risks of the procedure(s) under consideration, and potential benefits for the patient. Because the contents of the normal speech signal have not been defined in a way that permits a surgeon systematically to provide alternative auditory signals to a deaf patient, the burden is placed on the surgeon to make an arbitrary selection of candidates and available devices for cochlear prosthetic implantation. In an attempt to obtain some information regarding the ability of a deaf patient to use electrical signals to detect and understand speech, the Good Samaritan Hospital and Neurological Sciences Institute cochlear implant team has routinely performed tympanotomies using local anesthesia and has positioned temporary electrodes onto the round windows of implant candidates. The purpose of this paper is to review our experience with this procedure and to provide some observations that may be useful in a comprehensive preoperative evaluation for totally deaf patients who are being considered for cochlear implantation.

Postinflammatory acquired atresia of the external auditory canal: late results of surgery

Postinflammatory atresia of the external meatus following recurrent external otitis or chronic otitis media has been treated in twenty-two ears with endaural excision of the fibrous tissue and coverage of the denuded drum and bone of the medial part of the external ear canal with a split-skin transplant. Primary and late results are presented. During the first six months postoperatively, the patients developed recurrent atresia. At follow-up, with a median observation time of five years, no further progression of atresia had occurred. Hearing improvement has been considerable after removal of the atresia, and in many ears the air-bone gap was closed, so the patient also benefited from the operation in the long run.

Sensorineural hearing loss

New developments in diagnosis aid in the treatment and have improved the outlook for those patients with sensorineural hearing loss. Not all such hearing loss is untreatable and it should be approached systematically and enthusiastically. Thorough evaluation should be performed in all patients.

The bionic ear: principles and current status of cochlear prostheses

The field of cochlear prostheses is reviewed, emphasizing the neurophysiological principles necessary for the development of a successful cochlear prosthesis. Pertinent auditory physiology is reviewed, and four conditions are proposed which, if met, should result in speech recognition by the patient with an implant. These conditions are: The surviving neural population must be adequate over the frequency distribution required to deliver the necessary information for speech discrimination. The central neural processing pattern for decoding and recognizing speech must have been established and still persist. The processing of the acoustic signal by the auditory system up to the level of the prosthesis interface must be understood and predictable from the acoustic stimulus. The relationship between the response patterns of the neural elements and the electrical stimulus must be well documented and controllable. The degree to which these conditions can presently be met is discussed, with some suggestions for future development. The function of the cochlear prosthesis is separated into a signal processing section and an electrical stimulus section. Two signal processing strategies are analog processing of the acoustic signal and speech feature extraction from the acoustic signal. Four possible electrical stimulation strategies are direct analog stimulation from the signal processor, pulse amplitude modulation, pulse width modulation, and stimulation designed to optimize the neural responses to electrical stimulation. Some of the present generation cochlear prostheses, including five approved by the FDA as investigational devices, are discussed according to this classification. The clinical results of testing these devices as aids to lip reading and as stand-alone speech reception aids are compared. All are a potential aid to lip reading. Some prosthesis designs have been implanted in patients who then showed exceptional open set speech discrimination. These exceptional patients have used both single channel and multichannel devices and devices with both analog processing and speech feature extraction strategies. These results are encouraging. More consistent and better speech reception is anticipated for the future as this field develops.

Verification of the air-bone gap using cancellation and evoked responses

Using the cancellation method as well as evoked responses, we investigated their application in the estimation of the air-bone gap in patients undergoing operation on middle ear structures. The cancellation method had a closer relationship with pure-tone audiometry than evoked responses in predicting the air-bone gap. This was caused by recruitment, by which the cancellation method was not affected. The results of brainstem-evoked responses to bone and air conduction signals showed therefore an underestimation in the prediction of the air-bone gap. Combining the cancellation method with evoked responses elicited to air conduction signals permitted the estimation of the cochlear reserve without the need of threshold measurement by bone conduction.

Speech discrimination in advanced otosclerosis following stapedectomy

This paper studies the changes in speech discrimination following stapes surgery in patients with advanced otosclerosis. Two thirds of these patients showed a postoperative improvement in the discrimination score with obvious correlation with closure of bone-air gap. The results were slightly worse in comparison to those obtained on otosclerotic patients with good bone conduction. In advanced otosclerosis even a minimal impairment in bone conduction and/or an incomplete closure of the gap interfere with discrimination.

Middle fossa vestibular neurectomy: an update

Middle fossa section of the vestibular nerve is a neurotologic skull-base procedure that has found a successful, albeit limited, role in the surgical management of Meniere's disease. Incapacitating vertigo can be controlled in 94% of the cases, while serviceable hearing is maintained in 70%. Tinnitus and aural pressure are reduced in 60% and 80% of cases, respectively. The morbidity of this approach is similar to that of other destructive procedures of the labyrinth when careful patient selection and precise surgical technique are employed. In the incapacitated vertiginous patient with serviceable hearing, middle fossa vestibular nerve section should be considered as an alternative to other destructive procedures involving the otic capsule.

Experiences with ESR (endolymphatic sac revascularization) in cases of sensorineural hearing-loss

Experience based on 14 cases of severe-to-total sensorineural deafness, treated with endolymphatic sac revascularization, operation, is presented. Changes seen in the endolymphatic sacs and lateral sinuses of these patients have been detailed. Irrespective of the degree and duration of deafness, significant hearing gain (with good improvement in speech discrimination) was obtained in nine out of 14 cases (64.28 per cent). There was no improvement at all in one out of 14 (7.14 per cent), and there was a relapse of the hearing-loss two months post-operatively in one case (7.14 per cent). Tinnitus disappeared in the operated ear in three out of five cases (60 per cent) and vertigo improved considerably in four out of six cases (66.66 per cent). The follow-up in this series has been up to two years.

Labyrinthine ossification secondary to childhood bacterial meningitis: implications for cochlear implant surgery

Of 20 children who underwent cochlear implantation for profound sensorineural hearing loss secondary to bacterial meningitis, 14 had round-window and cochlear ossification at surgery. Preoperative polytomography demonstrated ossification in 11 of these. The incidence of ossification was highest after meningitis secondary to pneumococcal pneumonia. In only one of four children with severe ossification of the labyrinth was implant surgery unsuccessful. Preliminary results indicate that mild labyrinthine ossification is not a contraindication to cochlear implantation.

Perilymphatic gusher and stapes surgery. A predictable complication?

The cases of 3 patients who had 'perilymph gushers' following stapes surgery are reported. The similarities in their clinical histories and examinations are discussed. All 3 were males and had progressive mixed deafness presenting in early childhood. Polytomography revealed anomalies in both the vestibule and internal auditory meatus in 1 patient; the stapedial reflex was unexpectedly large in all 3. Further preoperative evaluation of these features in other patients and patients affected by the X-linked deafness syndrome is indicated in order to assess the validity of the above criteria.

Stapedectomy revision of the wire-Gelfoam prosthesis

Revision procedures in which a vein graft with a Robinson stapes prosthesis was used are reviewed in 100 patients. In all cases a wire-Gelfoam stapes prosthesis had been used initially. The surgical findings were prosthesis malfunction, 48%; eroded incus, 16%; negative findings, 14%; footplate not removed, 11%; oval window fistula, 7%; and incus problems, 4%. Postoperatively, hearing in 70.5% of the patients with conductive hearing loss was within 10 dB and 84.5% within 20 dB. The high success rate is affected by the fact that patients with conductive hearing loss were separated from those with sensorineural hearing loss, a piston prosthesis on tissue was used in the revision surgical procedure, and patients with otosclerosis regrowth did not undergo revision. Surgical directives to minimize hearing loss included use of a tissue seal over the oval window; not reopening the oval window; monitoring the patient for dizziness; performing audiometric tests during surgery; leaving the wire in place in certain cases; and not revising the prosthesis in patients with otosclerosis regrowth.

Findings and long-term surgical results in the hearing loss of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is an inherited connective-tissue disorder of variable penetrance. With OI, the triad of blue sclera, osseous fragility, and a conductive hearing loss is known as the van der Hoeve-de Kleyn syndrome. Blue sclera with a conductive loss may be a clinical subgroup of OI. Clinical findings and long-term surgical results in 62 operations in 43 patients with blue sclera are given. Osteogenesis imperfecta differs from otosclerosis in the following ways: (1) earlier onset (in the second and third decades of life), (2) more severe middle ear involvement, and (3) a higher incidence of sensorineural hearing loss. One year after stapedectomy, 38 (75%) of 51 operations had complete closure of the air-bone gap. Of the 24 operations followed up for an average of seven years (range, two to 18 years), 15 patients (62%) had no deterioration in their immediate postoperative hearing gain. Our study supports the concept that OI is clinically distinct from otosclerosis and establishes surgical intervention for its conductive hearing loss as a reasonable alternative to amplification.

Preservation of cochlear nerve function with the aid of brain stem auditory evoked potentials

Somatosensory, visual, and auditory evoked potentials have been used to monitor neurological function in patients under general anesthesia. This paper describes the preservation of useful hearing in three patients with cerebellopontine angle tumors. In each case, cochlear function was monitored during the procedure, and confirmation of intact conduction intraoperatively was associated with preserved hearing postoperatively.

Simultaneous round and oval window fistulae in a child

Sudden hearing loss from simultaneous rupture of both oval and round windows, occurring in the only hearing ear of a child, is described. The condition was surgically managed with recovery of hearing. Of particular note was the presence of air aspirated into the labyrinth at the time of membrane rupture, which has not previously been described. The possible mechanisms and some clinical correlates associated with anatomic predisposition to such rupture are discussed.

Results of endolymphatic sac surgery in advanced Meniere's disease

A rational surgical approach to Meniere's disease eludes us because of the uncertainty of the pathophysiology and the variability in the natural history of the disease. The results of different surgical techniques are difficult to compare because of differences in patient selection, methods of analysis, and length of follow-up reported. This study reviews long-term results in twenty-four ELS procedures in which the test group and parameters of evaluation are carefully described. The overall rate of vertigo control is 75 percent and incidence of significant hearing improvement is 25 percent. This low rate of hearing improvement is related to the selection of patients with advanced disease and other factors. In this series, surgery limited to simple decompression of the ELS proved generally more effective than shunt procedures. It is noteworthy that the Arenberg valve implant provided impressive results in a small number of revisions. Postoperative fibrosis appears to affect results adversely, therefore, measures to prevent scar tissue proliferation seem indicated.

Multichannel cochlear implants. Current status and future developments

The University of California, San Francisco has been active in the development of the multichannel cochlear implants for rehabilitation of total sensory deafness for the past 8 years. Patients implanted with experimental prototypes of the devices now in use have demonstrated that speech discrimination of 40% to 50% is possible for common everyday words and sentence material. These devices provide the same stimulation to each of the 8 bipolar pairs in the cochlea. They have an internal disconnect device which allows for replacement and upgrading of implanted receiver-drivers without disturbing the scala tympani electrodes. Application of these devices in a larger deaf population is currently underway. The present report discusses the current status of implants and the future developments we fell are necessary to achieve improved speech discrimination.

The Mondini dysplasia - a clinical study

The authors describe a clinical approach to the diagnosis and treatment of sensory-neural hearing loss associated to the Mondini dysplasia. The first element of diagnostic suspicion was represented either by a history of fluctuant and progressive hearing loss or by electrocochleography patterns showing multiple-peaked acoustic nerve action potentials similar to those observed in Ménière's disease. Confirmation of the diagnosis was obtained by temporal bone polytomography. An endolymphatic subarachnoid shunt was performed in 22 ears of 18 patients. The results, although preliminary, suggest that the shunt effectively contributes to stabilize the hearing and arrest the further progression of the hearing loss.

Incus reposition: goblet prosthesis

A stainless steel goblet shaped prosthesis is used to attach the repositioned incus to the stapes. A two year follow-up was made of the first 116 patients in which the prosthesis was used for ossicular reconstruction. The incidence of extrusion and ankylosis is diminished, and 75% of all cases had closure within 10 db. An additional 20% had closure within 20 db of bone conduction thresholds. Revisions have been less with this technique than with others: 40% of 116 patients had an uncomplicated tympanoplasty; 60% had a tympanoplasty with mastoidectomy. The results are, of course, more favorable in the group without mastoidectomy. Of these, 86% had closure to within 10 db of bone conduction level. These findings suggest that the use of the goblet prosthesis results in improved hearing. These findings conclude that the use of the goblet prosthesis results in better hearing than that obtained with other methods of ossicular chain reconstruction.

Isolated intralabyrinthine schwannoma

Although most vestibular schwannomas arise in the internal auditory canal, a more peripheral site of origin is possible. We report a case of isolated schwannoma limited to the labyrinthine vestibule. Our description of the location of this tumor is further documentation that schwannomas can arise from the terminal vestibular nerve fibers to the cristae or maculae. Either the nerve roots of the superior vestibular nerve to the utricle and horizontal and superior semicircular canal cristae, or the nerve roots of the inferior vestibular nerve to the saccule and posterior semicircular canal crista may have been the locus of origin of this unusual tumor. Intralabyrinthine schwannoma should be included in the differential diagnosis in the face of progressive auditory and vestibular dysfunction. Because conventional roentgenographic studies usually fail to demonstrate the presence of schwannoma in this location surgical exploration of the labyrinthine vestibule in the presence of unserviceable hearing and incapacitating vertigo is indicated.