Induced temporary threshold shift in guinea pigs.

The etiology of an incidentally discovered temporary threshold shift observed in an experimental animal (Harley guinea pig) is discussed with its potential implications for auditory research.

Overlay versus underlay tympanoplasty. Part I: historical review of the literature.

The history of otology is the history of the successful treatment of infections of the middle ear and the eardrum. Otologists have sought to restore hearing lost to infections of the eardrum since the 1600s. The development of instruments, techniques, and materials to treat infection is fascinating because of the serendipitous nature of the discoveries and the insight of the discoverers. This historical review describes the history of the treatment of infections of the ear and the development of modern techniques of ear surgery. Two contemporary methods of tympanic membrane repair are then described.

Overlay versus underlay tympanoplasty. Part II: the study.

This report compares two contemporary techniques of tympanic membrane repair. The prospective comparison study included 712 cases over 9 years. Whether the tympanic membrane was repaired by an underlay or an overlay technique, results were reliable. By making a postauricular incision, greater visibility of the operative site can be obtained. Larger perforations can be closed more reliably when greater exposure is obtained. The placement of the graft above or below the annulus is not the issue. Careful technique and precise work are the keys to successful tympanoplasty. Thus otologic surgeons should cultivate effective techniques, attempting to continuously improve their results to achieve perfection.

The management of congenital cholesteatoma: surgical results of 42 cases.

Radical surgery for congenital cholesteatoma leaves the patient, usually a child, with an ear that requires care for life. At the Otologic Medical Group, the intact canal wall technique has been used for many patients with cholesteatoma. To determine results of this management in the treatment of congenital cholesteatoma, we reviewed records of all patients treated between 1974 and 1985. Forty-two ears were studied in 41 patients. A closed middle-ear space was achieved in all cases, and an intact canal wall was maintained in 41 (98%). Follow-up averaged 4.3 years. Of the 41 cases with serviceable hearing before surgery, 28 (68%) had postoperative hearing within 10 dB of the best preoperative bone conduction threshold. Thirty-eight of the 41 achieved a final hearing result within 20 dB of the best bone conduction threshold.

Reconstructing the absent lenticular process.

When a surgeon encounters an absent lenticular process of the incus, he must either reposition the incus or attempt to bridge the small gap between the remaining incus long process and the stapes capitulum. Our solution to this problem is to place a Lippy modified Robinson stapes prosthesis on the stapes footplate and attach it to the remaining long process, thus bypassing the stapes superstructure. This modified Robinson prosthesis has a portion of the well removed allowing the eroded long process to enter from the side. The hearing results of 63 cases at 6 months (two-thirds of which had a concurrent tympanoplasty) are 67% within 10 dB and 91% within 20 dB of the preoperative bone hearing level. The use of an existing and proven prosthesis provides both stability and, to date, the most successful hearing results for reconstructing the absent lenticular process.

Cochlear histopathology in the labyrinthectomized ear: implications for cochlear implantation.

Limited damage to the cochlea and preservation of hearing after labyrinthectomy have been the subject of many case reports. One might hypothesize that, even when hearing is lost, there may be less damage to the cochlea than anticipated, and some neural elements that can be electrically stimulated may be preserved. Four labyrinthectomized temporal bones on file at the House Ear Institute were evaluated histopathologically. All had some remaining spiral ganglion cell population, the neural element that we think is stimulated by the intracochlear electrode. We also examined the population of hair cells and dendrites and the presence and extent of cochlear ossification, factors that may influence the performance of a cochlear implant. This is the first study of its type. Results indicate that cochlear implantation in the labyrinthectomized ear may be feasible.

Practical use of total and partial ossicular replacement prostheses in ossiculoplasty.

The use of porous polyethylene total and partial ossicular replacement prostheses (TOPs and POPs) for ossicular reconstruction in middle ear surgery was retrospectively reviewed at the Warren Otologic Group, a tertiary referral center for otologic problems. Extrusion rates, lower than those previously reported, and improvement in hearing results were found in 250 cases. Follow-up ranged from 6 months to 8 years. This paper details the optimal placement and relationships of the prosthesis, the interposed tragal cartilage, and the drum. Modifications to the prosthesis have increased stability and ease of reconstruction. The hearing results of both TOP and POP reconstruction, and comparison with the literature, will be presented. With TOPs, the air-bone gap was closed to within 20 dB in 67% of cases. With POPs, similar results were obtained in 81% of cases.

Stapedectomy in patients with small air-bone gaps.

Controversy exists concerning stapedectomy for patients with small air-bone gaps. The purpose of this study was to examine the results for patients who had a stapedectomy to correct a small (10 dB or less) air-bone gap. One hundred fifty-four patients with suspected otosclerosis were explored and a stapedectomy was performed in 136 (88.3%) of these cases. The mean pure-tone average (PTA) improved 16.7 dB and overdosed the preoperative bone conduction PTA by 8.1 dB. The majority of the stapedectomy patients (89.7%) had a PTA closure greater than or equal to 0 dB. These results showed that stapedectomy can be an effective procedure for eliminating and overdosing even small air-bone gaps due to otosclerosis.

Partial ossicular reconstruction in children: a review of 62 operations.

OBJECTIVE/HYPOTHESIS: The published experience and audiometric results with ossicular reconstruction in children are limited. To better understand the role of ossiculoplasty in children, audiometric results were examined for partial ossicular reconstructions performed on a pediatric population. STUDY DESIGN: Retrospective. METHODS: Sixty-two partial ossicular reconstructions performed on a pediatric population were reviewed for audiometric results, prosthesis extrusion rates, and mechanisms of failure at revision. Comparison of techniques and prosthesis types: porous polyethylene partial ossicular replacement prosthesis (POP), Schuring ossicle cup (SOC), and modified Robinson prosthesis (MRP) were also evaluated. Follow-up ranged from 6 to 72 months. RESULTS: Six-month hearing results showed postoperative airbone gaps less than or equal to 20 dB in 77% of cases. Successful results at 1 and 2 years were retained in 66% and 63% of cases, respectively. Results for POPs at 1 and 2 years were 78% and 89%. Results for SOCs at 1 and 2 years were 61% and 55%. The overall extrusion rate was approximately 3%. CONCLUSIONS: These results compare favorably with those from other, mostly adult, studies. Comparison of prosthesis types revealed generally stable long-term results with few significant differences. Success with ossiculoplasty in children can be obtained by applying the same principles and approach to ossicular reconstruction as used in adults. Ossicular reconstruction in children remains a secondary goal after establishing a safe, dry, and stable ear. A discussion of techniques and comparative literature review are presented.

Short- and long-term results of stapedectomy in children.

Studies have indicated that stapedectomy can be an effective procedure in children for correcting conductive hearing losses due to juvenile otosclerosis. However, because childhood otosclerosis is rare and children commonly choose to use hearing aids in lieu of undergoing surgery, little outcome data are available. The purpose of this retrospective study was to provide additional outcome data in both the short and the long term. Stapedectomies were performed on 47 children. Preoperative hearing results were compared with 6-month postoperative hearing results. Hearing results for the children who had long-term follow-up (5 years or more) were compared with the 6-month postoperative results. Stapedectomy was successful (postoperative air conduction pure-tone average [PTA] within 10 dB of the preoperative bone conduction PTA) in 91.7% of the cases. The mean overclosure of the preoperative bone conduction PTA by the postoperative air conduction PTA was 0.2 dB. The mean PTA hearing improvement was 32.8 dB. Results from the 21 children (28 ears) who had long-term follow-up indicated an average 0.7 dB/year PTA worsening from the 6-month postoperative PTA. Results from this study provide additional evidence that stapedectomy can be an effective procedure for correcting conductive hearing losses due to juvenile otosclerosis.

Acoustic reflexes, auditory brainstem response, and MRI in the evaluation of acoustic neuromas.

Patient records were reviewed to determine whether persons with absent acoustic reflexes have a higher incidence of abnormal auditory brainstem response (ABR) results in the absence of a cerebellopontine angle (CPA) tumor than those with normal acoustic reflexes. Results showed patients with absent reflexes to have borderline or abnormal ABR results in 45.2% of the cases. Patients with normal reflexes had borderline or abnormal ABR results in 14.2% of the cases. Results indicate that magnetic resonance imaging is a more appropriate test for patients with absent reflexes, since ABR was often nondiagnostic for a CPA tumor in this group.

Perilymph fistulas: the House Ear Clinic experience.

The diagnosis, evaluation, and surgical treatment of perilymph fistulas has recently been the focus of a great deal of attention in otology. Authors have focused on perilymph fistulas as the cause of hearing loss and vertigo in many diverse situations. Additionally, surgical repair has been suggested when there is little objective support for intervention. To address some of the problems inherent in the diagnosis and treatment of perilymph fistulas, records of patients operated on at the House Ear Clinic during the past 12 years were reviewed retrospectively. Eighty-six patients were surgically explored for fistulas during this period. Thirty-five (40.7%) fistulas were found, and 51 ears were patched whether fistulas were found or not. Of the 80 patients who were seen for follow-up, 35 (43.8%) were subjectively better, and 45 (56.2%) were the same. Although the number of fistulas found and the number of patients improved were similar, the composition of the two groups was different. On the basis of audiometric results, improvement in hearing occurred in only 18.7% of the patients. None of the demographic factors or diagnostic tests were predictive of either the presence of a fistula or the therapeutic outcome. Further work is required to facilitate the preoperative diagnosis of fistulas and to design appropriate surgical intervention.

Voice quality and intelligibility characteristics of the reconstructed larynx and pseudolarynx.

The ideal laryngeal substitute would provide a voice with good intelligibility, volume, and character. The basic components of these qualities are being studied in our laboratories to refine laryngeal reconstruction and replacement techniques. Exact definition of these characteristics may then be translated into specific requirements for reconstruction. In this study the phonation of laryngectomees using hand-held artificial laryngeal devices and patients with reconstructed larynges was compared with that of normal speakers. Presentations were evaluated by adult listeners with normal voice and hearing, and intelligibility scores were developed. These studies show, in part, that the fundamental frequencies at which various artificial speech aids are used do not significantly correlate with user intelligibility. Computerized spectral analysis was then utilized to ascertain the unique acoustic characteristics of the voices. Further computer analysis was carried out to determine what characteristics of the normal speakers' voices were shared in common with patients using artificial devices and patients with reconstructed larynges. Initial attempts at using these findings in laryngeal reconstruction based on computer modeling will be presented.

Comparison of geometric and "real" surface areas of cochlear electrodes.

The destructive potential of the electrically active electrode is believed to be related to charge density at the electrode-tissue surface. Charge density has been calculated with the use of both geometric and electrochemical "real" values for surface area. To further assess the accuracy of surface area measurements determined by means of the previously mentioned methods, an eight-electrode modiolar array cochlear implant was examined. Electrode surface areas were measured first electrochemically, then by means of a light microscope, and finally with the use of the scanning electron microscope. Comparison of these measurements demonstrated a high correlation between the scanning and light microscopic values. However, there was no correlation between the surface areas determined by light and scanning electron microscopy and the electrochemical measurements.

Ossiculoplasty in canal wall down mastoidectomy.

OBJECTIVE: The aim of this study was to evaluate the initial and longer term success of closing the air-bone gap (ABG) to 20 dB in ossiculoplasty with canal wall down mastoidectomy. METHODS: This study was conducted at a private otologic practice. Patients included those who underwent ossiculoplasty from 1989 to 1996 with canal wall down mastoidectomy, whether primary or revision (33 from a total of 387 tympanomastoidectomies). Outcome measures included ABG closure, long-term hearing stability, mastoid appearance, extrusion, and sensorineural hearing loss. RESULTS: Almost 64% of ABGs were closed to within 20 dB. The mean pure-tone average improvement was 12.3 dB. The mean PTA hearing decline in the years after surgery was slightly less than 1 dB/year. CONCLUSION: Hearing improvement with a stable long-term hearing result is possible with canal wall down mastoidectomy. The potential for hearing gain is greatest for patients having larger preoperative ABGs.

A postoperative audiometric evaluation of cochlear implant patients.

As the benefits of the cochlear implantation become more defined, many investigators hope that these devices can be offered to patients with a lesser degree of hearing loss. Accordingly, it is necessary to investigate the audiometric thresholds in the implanted ear after surgery. Preservation of the residual hearing after implantation would support the claims that surgery and the presence of a cochlear implant do not adversely affect the implanted ear.

Prosthesis size in stapedectomy.

Primary stapedectomies were performed on 60 patients with bilateral otosclerosis. Every patient had a 4 mm long Robinson prosthesis with a 0.4 mm wide shaft placed in one ear and a 4 mm long Robinson prosthesis with 0.6 mm wide shaft placed in the opposite ear. With the 0.4 mm wide prosthesis, 54 patients overclosed the air bone gap and 6 were within 10 dB of closing. With the 0.6 mm wide prosthesis, which was placed in the opposite ear, 51 patients overclosed their air-bone gap and 8 were within 10 dB of closing. We conclude that there is no statistical difference in hearing results between the 0.4 mm and the 0.6 mm wide Robinson prosthesis when they are used in a partial stapedectomy with a vein graft covering the oval window.

Revision stapedectomy for incus erosion: long-term hearing.

One of the most common ossicular problems in revision stapedectomy is the eroded incus. Revision surgery has been reported as successful in 70% to 80% of cases at 1 year. Little is written about long-term results or the association of erosion with various prostheses. We evaluated 83 cases from 1 to 20 years, including multiple revisions. In 23 cases the erosion was seen at initial stapedectomy. Surgery was performed with the patient under local anesthesia, with the use of the Lippy modified prosthesis. Initial success was seen in 72% (41/57), satisfactory results in 90%, no change in 5%, and none worse. At 10 years, success had declined to 50% (7 of 14), with 80% satisfactory. The numbers for multiple revisions were lower. Success in nonrevision cases was 90% (21 of 23), dropping to 86% at 10 years, with satisfactory results in 100%. The type of prosthesis associated with erosion was a crimped wire in 34% (24 of 70), a plastic strut in 23%, and a Robinsion prosthesis in 17%. We conclude that the risk of incus erosion appears less with the Robinson prosthesis. The Lippy modified prosthesis yields good long-term results, particularly when erosion is seen at initial stapedectomy. Results worsen with subsequent revision.

Early speech changes in children with multichannel cochlear implants.

A number of studies have demonstrated that cochlear implants provide an improved auditory signal and enhance the development of speech-perception and production skills for profoundly deaf children. However, exactly when these early speech skills begin to develop remains unclear. To explore this issue, we observed, for a 1-year period, four prelingually deaf children who underwent implantation consecutively within 1 month of each other, and we paid particular attention to the first few months of rehabilitation. We found immediate speech scores as early as the first day of implant tune-up. Speech production continued to improve rapidly throughout the first 4 months but exhibited a generally slower rate of progress in some of the speech-production skills at 1 year. We also found vowel-production skills to be the easiest to achieve, with word-pattern recognition and consonant voicing of intermediate difficulty. Consonant placing and manner of consonant production were the hardest skills to achieve. Results of speech-perception tests 1 year after implantation were markedly improved over preimplantation levels in three of the four children. These early speech changes stress the need for maximization of the capability of the cochlear implant by institution of immediate and intensive speech rehabilitation efforts for prelingually deaf children.

Staging for cholesteatoma in the child, adolescent, and adult.

A closed tympanomastoidectomy with subsequent staged surgical procedures leading to the excision of cholesteatoma was validated as described. All elements of staging with a 10-year experience of 354 patients are covered according to categories of child (0 to 9 years), adolescent (10 to 15 years), and adult. The child differed from the adolescent and adult in the following manner: more recurring cholesteatomas, greater ossicular necrosis, poorer hearing results, less aggressive residual cholesteatoma, and significantly poorer results with pars flaccida cholesteatoma than pars tensa cholesteatoma. After the end stage, 90% of the cases remained closed, with acceptable hearing in 60% of the patients.