Audiologic Outcomes After Vestibulotomy in Patients With Congenital Absence of the Oval Window

OBJECTIVE

To examine the clinical features and surgical outcomes in patients with congenital absence of the oval window (CAOW), and to investigate the potential factors that affect audiologic results.

STUDY DESIGN

A retrospective chart review.

SETTING

A tertiary academic center.

PATIENTS AND INTERVENTION

A total of 17 ears among 16 patients were confirmed to have CAOW. Among them, 13 ears underwent vestibulotomy for hearing reconstruction. Clinical parameters associated with the hearing outcomes were analyzed.

MAIN OUTCOME MEASURES

A mean air-bone gap (ABG) after 6-month and long-term follow-up was compared with preoperative measurements.

RESULTS

Intraoperative findings showed that anomalies of the malleus or incus were observed in 11 ears (64.7%), stapes anomalies were present in all ears (100%), and facial nerve anomalies were present in 10 ears (58.8%). Because of unfavorable facial nerve anomalies, hearing reconstruction was aborted in four cases (23.5%). In the hearing reconstruction group, the mean ABG at 6 months postoperation was significantly reduced after compared with the preoperative value (44.0 ± 8.4 dB versus 58.8 ± 9.1 dB, p = 0.006). After dividing ears into a success subgroup (ABG ≤ 30 dB, seven ears) and non-success subgroup (ABG > 30 dB, six ears), the use of a drill during vestibulotomy was significantly related to a poor hearing outcome (100% versus 16.7%, p = 0.015). The long-term follow-up result (mean, 60 mo) revealed no deterioration compared with the 6-month postoperative result. Five ears (29.4%) underwent revision surgery, and three of them showed ABG improvements. No serious complications were reported.

CONCLUSION

Vestibulotomy is an effective and safe option for hearing restoration in patients with CAOW, particularly when the use of a drill is not required. The long-term audiologic outcome is also reliable.

Oval window niche height: quantitative evaluation with CT before stapes surgery for otosclerosis

BACKGROUND AND PURPOSE

Stapes surgery for otosclerosis can be challenging when the oval window niche is narrow. We analyzed the reliability of CT to evaluate the height of the OWN and propose a quantitative criterion to distinguish normal and narrow OWNs.

MATERIALS AND METHODS

Fifty-six patients were scheduled for primary stapes surgery and, with available preoperative CT scans, were prospectively enrolled in the study at a tertiary care hospital. OWN height was measured on coronal CT and qualitatively evaluated during surgery. CT findings and surgical observations were matched to determine the preoperative imaging criterion of a narrow OWN.

RESULTS

OWN was found to be narrow during surgery in 8 of 56 patients (14%). On CT, mean OWN height measurement was 1.1 mm for the narrow group and 1.8 mm for the normal OWN surgical cases. The cutoff between normal and narrow OWN was computed at 1.3 mm by using discriminant analysis and at 1.4 mm with boxplot analysis. These CT cutoff values allowed a correct classification of "normal" and "narrow" OWN, compared with visual evaluation during surgery.

CONCLUSIONS

Measurements of the OWN height provide an accurate and relevant evaluation of this region before otosclerosis surgery. A width below 1.4 mm should be considered at risk for technical difficulties during the stapes footplate approach.

Clinical results with an active middle ear implant in the oval window

BACKGROUND

Some patients with chronic middle ear disease and multiple failed revisions, who also need a hearing aid, may benefit from an active middle ear implant. An advantage of an active middle ear implant is that the ear canal is unoccluded.

METHODS

Following extensive experimental development in temporal bones and investigations of various locations and attachments of a Vibrant Soundbridge transducer, a new titanium clip holder for the vibrant floating mass transducer was developed. This assembly is a total ossicular replacement prosthesis (TORP) that is placed on the stapes footplate. Six patients were implanted with this device.

RESULTS

Acoustic results demonstrate significantly improved gain, especially in the high frequencies, which is typically unobtainable by conventional hearing aids.

CONCLUSION

The simple procedure of placing an active TORP assembly on the stapes footplate, similar to the implantation of a passive TORP prosthesis during tympanoplasty, offers promising treatment for cases of incurable middle ear disease.

Advantages and risks of various sealing procedures of the oval window: vein graft, adipose tissue, gelfoam, merogel

An overview of various proposed sealing procedures of the oval window proposed for stapedectomy or stapedotomy are presented. These include vein graft, adipose tissue and substances like Gelfoam or Merogel. The advantages and pitfalls with these materials are discussed.

Success rate in revision stapes surgery for otosclerosis

OBJECTIVE

The aim of this study was to evaluate the hearing results of revision stapes surgery performed because of previously failed operations and to determine the causes of failure.

STUDY DESIGN

Retrospective review of revision stapes operations.

SETTING

Tertiary referral center.

PATIENTS

Sixty-three consecutive revision stapes operations were performed in 56 patients over a period of 12 years (1992-2004). The indication for revision surgery was recurrent or persistent air-bone gap greater than 20 dB after primary surgical treatment of otosclerosis of the oval window.

RESULTS

All patients were operated on to improve hearing. Sixty-three revision stapes operations resulted in closure of the air-bone gap to 10 dB or less in 52.4% of cases. The average postoperative air-bone gap was 13.1 dB, and the mean pure-tone average improvement was 12.9 dB. In six patients (9.5%), revision surgery produced no change in hearing, and in four (6.3%) the hearing decreased by 5 dB or more. In one patient, the operation resulted in a profound hearing loss. Prosthesis malfunction was the most common primary cause of failure (60.3%). The original prosthesis was replaced with a new one in 48 cases. In 30 of these (62.5%), closure of the air-bone gap to within 10 dB was achieved. In 15 cases, the prosthesis was not replaced, and in only four of these (26.7%), closure of the air-bone gap within 10 dB was obtained (p < 0.022).

CONCLUSION

Revision stapes surgery is less likely to be successful than the primary operation. Closure of the air-bone gap to within 10 dB was achieved in 52.4% of patients. The success rate was better in cases where the original prosthesis was replaced with a new one. The risk for decreased bone-conduction threshold does not seem to be higher than in primary surgery.

[Long term results stape surgery]

For many years otosclerosis has been an interesting otologic problem in regard to pathological and clinical aspects. Many various conceptions of otosclerosis development which finally lead to the stapes immobility in the oval window were discussed. Resent genetic studies indicate that genetic factors as a cause of otosclerosis possibly in combination with other factors localize 3 genes responsible for otosclerosis to chromosom 15q25q-q26, 7q34-36, 6p21-22. The aim of the study was audiometric evaluation of 1380 patients out of 1716 stapes operations performed in years 1973-2004. Audiometric assessment for air and bone conduction was performed according to the European Academy of Otology and Neuro-Otology (EAO-NO) criteria. Postoperative air-bone gap 11-20 dB for speech frequencies (500, 1000, 2000, 4000 Hz) was obtained in 64.8% and in 28.9% was less than 10 dB. Postoperative air-bone gap (11-20 dB) recognized as a good result is determined by factors such as preoperative hearing loss, onset and duration of the disease, advanced and multiple otosclerotic foci, patient's age etc. Actually postoperative air-bone gap shows the improvement of air and bone thresholds obtained post stapedotomy versus preoperative air bone gap. In previous years an "over-closure" effect was taken into consideration. Hearing improvement post stapes surgery which included the "over closure" effect was obviously better. The authors indicate the necessity of standardization of audiometric results post ear surgery.

Fallopian canal dehiscences: a survey of clinical and anatomical findings

This survey investigates fallopian canal dehiscences in order to assess the risk of encountering an unprotected facial nerve during routine ear surgery. In a prospective non-randomized study, the intraoperative appearance of the facial canal in 357 routine ear operations was compared with 300 temporal bone specimens from 150 autopsies. Intraoperatively, a dehiscence was detected in 6.4% (23/357) of the operations, most frequently at the oval niche region (16/23 cases). The incidence increased with the number of operations (P<0.0002). Cholesteatoma surgery had the highest relative risk (RR 4.6) of exposing an unprotected facial nerve. Postoperatively, no persistent facial paralysis was observed. In four of five cases with a transient facial palsy due to local anesthetics, a bony dehiscence could be found. The anatomical study revealed fallopian canal dehiscences in 29.3% (44/150) of the autopsies. One-third (15/44) of the individuals affected displayed bilateral findings, thus resulting in 19.7% (59/300) of temporal bones affected. A total of 17/59 bones showed microdehiscences, and most (55/59) were located at the oval niche. The actual prevalence of fallopian canal dehiscences is significantly higher than intraoperative findings suggest. The oval niche is the most affected region. High-resolution computed tomography is of diagnostic value only in selected cases. Facial paralysis following local anesthesia is the most significant clinical sign. Vigilance in acute facial palsy after local anesthetics and in cholesteatoma surgery and adequate intraoperative exposure help to prevent iatrogenic injury of the uncovered nerve. In unclear cases, nerve monitoring can facilitate a safe outcome.

[The cartilage guide: a solution for anchoring a columella-prosthesis on footplate]

BACKGROUND

A torp (columella-prosthesis) is the typical ossicular reconstruction in cases of a destroyed stapedial arch. Yet, many unsatisfactory hearing results are due to the lack of a stable, reliable anchoring of the base of the prosthesis on the footplate. Some solutions have been postulated, amongst them the perforation of the footplate with a tiny spike at the lower end of the prosthesis, which, however, many otosurgeons regard as too dangerous for the inner ear. Specially designed silicone sheets cannot guarantee a permanent guide of the columella.

METHODS

From our good experience with cartilage in different reconstruction procedures, we therefore developed a cartilage guide for the oval window niche. An oval 2,5 x 3,5 mm cartilage with a central hole is cut out of a thin (0,2 - 0,3 mm) cartilage plate with a help of a cartilage punch, which we had designed in collaboration with Heinz Kurz manufacture. The cartilage is placed into the oval niche and its hole guides the prosthesis onto the centre of the footplate.

RESULTS

Temporal bone experiments demonstrated a reliable sound transport through this guide. Revision surgery revealed a stable ingrowth of the cartilage plate into the oval niche, its perforation securely guiding the prosthesis similar to a piston on to the footplate. The first short time hearing results (max. 1 year) in 22 patients confirmed the acoustic quality of this stabilisation of a columella on the footplate as compared to a matched control group.

CONCLUSIONS

The stabilization of the columella with a cartilage-guide might solve one of the many problems with unsatisfactory hearing results after the reconstruction of a completely destroyed ossicular chain.

Vein versus tragal perichondrium in stapedotomy

OBJECTIVE

To assess, in otosclerosis surgery, whether the vein or the tragal perichondrium in stapedotomy with interposition yields the better long-term hearing outcome.

STUDY DESIGN

A retrospective chart review of prospectively collected audiometric data of 452 ears.

SETTING

Academic tertiary otology-neurotology referral center.

PATIENTS

Four hundred fifty-two stapedotomies with interposition were performed in 412 patients (bilateral in 40 patients) by the senior author (R.C.) between 1987 and 1998. A tragal perichondrium graft was used in 314 cases and a vein graft was used in 138 cases as sealing material of the oval window.

MAIN OUTCOME MEASURES

Audiometric data were recorded at 4 months, at 1 year, and at 3 years after surgery after American Academy of Otolaryngology-Head and Neck Surgery guidelines, except for thresholds at 3 kHz, which were not available and which were replaced with those at 4 kHz.

RESULTS

There were no significant intergroup differences in initial or late postoperative hearing outcome with regard to change in the pure-tone average bone conduction and air-bone gaps, or sensorineural hearing loss. Ears treated with a vein graft showed statistically better postoperative 2-kHz air-bone gap closure (p =0.0157), but the pure-tone average air-bone gap difference was not significant. Postoperative air-bone gap closure to within 10 dB was achieved in 91% of cases in the vein group and in 76% of cases in the perichondrium group. Specific study of the bone conduction level at 4 kHz showed a sensorineural hearing loss greater than 10 dB in 8% of cases in the vein group and in 11% of cases in the perichondrium group. One case of complete sensorineural hearing loss was observed with a tragal perichondrium graft (0.22%).

CONCLUSION

These results suggest that the vein should be preferred to the tragal perichondrium in stapedotomy with interposition.

Partial Promontory Technique in Stapedotomy Cases With Narrow Niche

OBJECTIVE

The objective of this study was to examine clinical and audiometric outcomes of a laser partial promontory technique in stapedotomy cases with a narrow oval window niche.

STUDY DESIGN

We conducted a retrospective chart review.

SETTING

This study was conducted at a tertiary referral center.

PATIENTS

We studied 59 patients who underwent a partial promontory technique with stapedotomy between 1994 and 2000. Seventy-two patients who underwent primary stapedotomy without promontory technique served as a control group.

METHODS

Preoperative and postoperative audiometric results were obtained for 59 patients undergoing laser stapedotomy with a narrow oval window niche. The partial promontory removal was performed with a KTP laser. Results were compared with 72 primary laser stapedotomy cases without the promontory technique within the same time period and analyzed using paired Student t test.

RESULTS

Ninety percent of the partial promontory cases were successful (air-bone gap [ABG] <10 dB). The mean postoperative ABG was 5.1 dB, which was comparable to the non-promontory cases (p = 0.7). The mean change in postoperative bone conduction was also comparable (p = 0.98). There were no cases of sensorineural hearing loss. An overhanging facial nerve was present in 32% of the narrow niche cases and a dehiscent facial nerve was encountered in 17% of these cases.

CONCLUSIONS

Partial laser removal of the promontory as an adjunct to laser stapedotomy cases with a narrow oval window niche is a safe, effective technique with comparable results to primary laser stapedotomy.

Revision stapes surgery: the malleus to oval window wire-piston technique

OBJECTIVE

To determine the effectiveness of the malleus to oval window wire-piston revision stapes surgery technique.

STUDY DESIGN

A retrospective analysis of 243 stapes procedures performed by the senior author over a 10-year period identified 15 revisions. Five patients underwent a malleus to oval window wire-piston technique. All patients were followed for at least 6 months. The surgical outcome including audiologic data and complications are noted.

METHODS

Stapes surgery was performed on an ambulatory basis by way of a transcanal approach under local anesthesia with monitored sedation by the same surgeon using a laser technique and a stapes wire-piston prosthesis.

RESULTS

Among revision stapes procedures, there was no significant difference in the air-bone gap closure or complication rate between the incus to oval window and the malleus to oval window techniques. The average preoperative air-bone gap in all revisions was 32 dB, whereas the mean postoperative gap was 10 dB hearing loss.

CONCLUSIONS

In experienced hands, revision stapes surgery using the malleus to oval window stapes wire-piston prosthesis is safe and effective.

[Surgical management of Mondini dysplasia with cerebrospinal fluid leakage]

OBJECTIVE

To evaluate the clinical manifestation and surgical technique of Mondini dysplasia with cerebrospinal fluid (CSF) leakage.

METHOD

Three Mondini dysplasia with spontaneous cerebrospinal fluid leakage were treated by the authors. A transcanal tympanotomy were used to pack the vestibular cavity with muscle.

RESULT

Three children were first manifested with recurrent meningitis and spontaneous cerebrospinal fluid rhinorrhea. Further examinations found that the leakages were otogenic. One side or both sides Mondini dysplasia were confirmed by CT scanning of temporal bones. The leakages were all stopped by the primary surgical closure.

CONCLUSION

Mondini dysplasia should be considered in children with spantaneous cerebrospinal fluid otorhinorrhea. A temporal bone CT scan can confirmed the diagnosis. A transtympanic closure is very effective in the management.

Long-term results of a new stapedotomy prosthesis

The long-term results of a new, home-made stapedotomy prosthesis are presented. The innovations of this prosthesis concern both portions, design for attachment to the incus and shaft. Our series include a total number of 42 individuals with stapes fixation, operated using the new prosthesis, with a medical follow-up period between eighteen months and five years. Our innovations offer a proper and safe insertion of the prosthesis into the oval window associated with excellent manipulation and handling. These advantages could be of major importance for younger surgeons and trainees. Postoperative hearing results are similar to those achieved with other commercially available pistons.

Cerebrospinal fluid otorrhea in a patient with congenital inner ear dysplasia

A case of a 10-month-old boy with a cerebrospinal fluid (CSF) fistula in his right ear is reported. In the same ear, the patient also showed congenital inner ear dysplasia. The CSF fistula was obstructed surgically. Surgical exploration showed a fistula superior to the oval window and a normally shaped stapes. The stapes was removed and the fistula was closed by obliteration of the vestibulum with the temporal fascia and fat tissue. The location of the fistula was very rare; to our knowledge, this is the first reported case of CSF fistula superior to the oval window. The relationship between perilymphatic fistula and the microfissure revealed by temporal bone study is discussed.

The other ear: findings and results in 1,800 bilateral stapedectomies

OBJECTIVES

To determine the incidence of middle ear abnormalities in patients with bilateral otosclerosis, which could potentially affect successful stapedectomy, and the rates of success in these patients, including the chance of overclosure in the second ear.

STUDY DESIGN

Retrospective case review of operative and audiologic records.

SETTING

Private otology practice.

PATIENTS

One thousand eight hundred patients underwent 3,600 primary stapedectomies for bilateral otosclerosis.

INTERVENTION

Analysis of perioperative and follow-up audiograms with associated operative findings, including obliterative otosclerosis and solid footplates, dehiscent or overhanging facial nerve, narrow oval window niche, promontory overhang, and ossicular fixation or malformation.

MAIN OUTCOME MEASURES

Audiologic stapedectomy success was determined as overclosure or closure of preoperative air-bone gap to less than 10 dB at 1 year or more of follow-up.

RESULTS

The rate of finding any abnormality was 25%. Abnormalities present bilaterally were found in 135 patients (7%), with otosclerosis requiring an oval window drillout as the most common finding (41%), followed by dehiscent or overhanging facial nerves (25%). Success in patients with abnormalities was 78% overall, with bilateral overclosure in 40%.

CONCLUSIONS

Abnormal middle ear findings during stapedectomy occur in a significant percentage of patients. Reasonable rates of success and overclosure can still be expected, but this is somewhat finding-specific. The predictive value of these findings, the associated rates of success with potential impact on surgical counseling, and planning for the "other ear" are discussed.

[From the concept of permanent percutaneous connections to that of permanent percutaneous electrical connections]

Percutaneous abutment of an extra-oral implant provides two main functions: support of bone anchored hearing aid (BAHA) and fixing maxillofacial prosthesis (MFP). Further developing this concept, and using available surgical strategies and materials, leads to a new application in extra-oral implantology. We analyzed the evolution of concepts in the field of permanent percutaneous connection (PPC) to the new concept of PPEC (permanent percutaneous electric connection), presenting a clinical case.

Surgical treatment of vertigo by utriculostomy: an experimental study in sheep

The objective of this study was to develop and test an endolabyrinthic microsurgical procedure for treatment of vertigo, the utriculostomy. This involves the application of local heat for obtaining a fistula in the membranous labyrinth, so as to establish communication between the endolymphatic and perilymphatic spaces at the utricle level. Before the procedure, an experimental model using quail eggs was built for pre-evaluation, and macroscopic and histological studies were performed in the temporal bones of three healthy sheep. Following this, the utriculostomy was performed through the oval window in 12 sheep. A microthermocautery was conceived by the first author and developed at Hospital de Clinicas de Porto Alegre. This equipment allows for control of temperature and duration of exposure to heat. Three months after the surgery, the animals were killed. A histological study of the temporal bones was performed to assess whether communication had been created between the endolymphatic and perilymphatic spaces, or whether a neomembrane had developed in the cauterized region. Histological sections of the vestibule of eight animals (three normal, five surgical) were analysed. All non-surgical cases presented a normal utricle wall. Three surgical cases (60%) presented a neomembrane. The absence of identifiable perforations in the utricle wall and the presence of neomembrane areas in 60% of the operated bones suggest that utriculostomy is a promising procedure for the treatment of Meniere's disease.

[Postoperative complication in stapedectomy: excessive introduction of the prothesis in the oval window]

Postoperative failures and complications detected in patients who undergo surgery for otosclerotic disease are not uncommon in stapes surgery. Prosthesis displacement and incus necrosis are the most common findings in review stapedectomy. We report the case of a patient who had tinnitus, vertigo, and non-recovery of air conduction thresholds without neurosensorial lesions after stapes surgery. The suspected diagnosis of excessive introduction of the prosthesis in the oval window was confirmed by computed tomography, which showed the radio-opaque image of the McGee metal prosthesis. The prosthesis replacement and literature review are discussed.

The leaking labyrinthine lesion resulting from direct force through the auditory canal: report of five cases

The leaking labyrinthine lesion is treated by conservative methods or surgical procedures. With respect to the stapes, the surgical treatment is controversial. Five cases of middle ear injuries accompanying oval window rupture are reported herein. In each case, direct force through the auditory canal damaged not only the ossicular chain but also the oval window. Initial symptoms were sudden hearing loss with significant conductive disturbance and various degrees of unsteadiness. Spontaneous horizontal nystagmus directed toward the uninvolved ear was observed in each case. Tympanic cavities were promptly explored under general anesthesia and oval window injuries were confirmed. In each case, the damaged stapes was temporally removed from the oval window. Perilymphatic leakage was recognized in each case. Two patients had subluxation of the stapes with a paucity leakage. Three had complete luxation of the stapes with a relatively huge oval window fistula. Disrupted oval windows were repaired with temporalis muscle fascial grafts that were inserted under the middle ear mucosae surrounding the oval windows. The stapes were replaced in the repaired oval windows, and the ossicular chains were reconstructed without artificial grafts. Vestibular dysfunctions disappeared within 7 days, and satisfactory audiologic results were obtained in each case.

A new stapedotomy prosthesis: preliminary report

Our study describes a newly designed stapedotomy prosthesis which consists of two components: (1) a platinum ribbon, and (2) a Teflon shaft. The first innovation is a flattened 'tab' on the posterior aspect of the platinum ribbon. The second innovation concerns the dual diameter cylinder-like shaft. Our prosthesis was implanted into 25 individuals, who underwent stapedotomy for stapes fixation, and the results are shown and discussed. Our innovations offer a proper and safe insertion of the prosthesis into the oval window associated with excellent manipulation and handling. At the same time, maximum visualization of the surgical field is achieved, while the stepped-down design of the shaft prevents the prosthesis protruding into the vestibule.

[Functional long-term results after open cholesteatoma surgery and ossiculoplasty with allogenic ossicles in adulthood]

BACKGROUND

Characteristic features of cholesteatoma of the middle ear are destruction of the bone and a high tendency for recurrent disease. The choice of surgical procedure is determined by audiological results and the rate of recurrent cholesteatoma.

PATIENTS

One hundred fifty patients who underwent primary cholesteatoma surgery were investigated 3-5 years postoperatively. Preoperative and postoperative audiological results and rate of revision surgery were compared for the respective surgical procedures. All cholesteatomas were treated with an open surgical technique. The lateral attic walls and cholesteatomas were removed.

RESULTS

Cholesteotoma recurred in 15 patients (10%). Primary reconstruction of the ossicular chain with a tympanoplasty (type III) was performed in 98 patients in the first operation. Approximately 80% of patients treated with a type III tympanoplasty had a maximum postoperative air-bone gap of 20 dB in the main speech range, depending on the frequency. In about 50% of patients, this value was 10 dB or less. Comparison of preoperative and postoperative conductive hearing loss between 250 Hz and 8000 Hz revealed an improvement (p < 0.05) of 10 dB (500 Hz, 3000 Hz, 4000 Hz) and 15 dB (250 Hz, 1500 Hz, 2000 Hz, 8000 Hz).

CONCLUSIONS

In our opinion, a second look operation should be performed in cases where a large cholesteatoma cannot be removed with sufficient reliability. This applies especially to a cholesteatoma in the oval window. Here, we suggest second-look surgery after one year.

Identification of photoacoustic transients during pulsed laser ablation of the human temporal bone: an experimental model

Laser ablation of hard tissues during neurotologic operations has been accomplished with continuous-wave (CW) lasers in the visible and midinfrared spectrum. The mechanism of ablation at these wavelengths is secondary to photothermal-induced tissue destruction. As a result, significant thermal damage to surrounding tissue may occur. Pulsed ultraviolet (UV) lasers have been suggested as an alternative to the argon, KTP-532, and CO2 lasers currently used in clinical practice. The pulse length of Excimer lasers are considerably shorter than the thermal diffusion time of bone tissue, and as a consequence thermal injury is minimal. This makes pulsed lasers an attractive tool for tissue ablation in the ear: in essence a "cold knife." However, the short pulse width of Excimer lasers (typically 10-150 ns) can create large thermoelastic stresses in the ablation specimen. This study identifies the presence of these photoacoustic waves during the Excimer laser treatment of the cadaveric human temporal bone. A XeCl (lambda = 308 nm, tau p = 12 ns) excimer laser was used to ablate hard tissue surrounding the oval window and facial ridge with energies of 75, 45, 25, and 12 mJ/pulse. Spot size was estimated to be 0.5 mm2. Custom high-frequency polyvinyldifluoride (PVDF) piezoelectric film transducers were fabricated and attached to the promontory, round window niche, and facial ridges. The signals were amplified using a low-noise preamplifier and recorded on a digitizing oscilloscope. Photoacoustic waves were clearly identified. Notably, large acoustic waves were measured on the promontory and on both sides of the facial ridge. The implications and clinical relevance of these findings is discussed and compared to findings obtained from a model system.

Management of labyrinthine fistulae secondary to cholesteatoma

Improvements in diagnosis and management of chronic ear disease in general and cholesteatoma in particular have led to a decreased incidence of serious labyrinthine complications. Unfortunately, significant disease still does occur and, if unrecognized, may result in significant morbidity. Labyrinthine fistulae secondary to cholesteatoma cause potentially irreversible symptoms such as hearing loss and vertigo. This study reviews 17 patients who developed labyrinthine fistula secondary to cholesteatoma. Sixteen involved the horizontal semicircular canal and one involved the oval window. The cholesteatoma matrix was removed in all cases and the underlying fistula repaired primarily. Cochlear function was preserved in all patients. Sixteen of 17 patients have had no further difficulty with vertigo beyond the immediate postoperative period. The evaluation and contemporary management of this difficult problem are discussed.

[High resolution computerized tomography of middle ear abnormalities]

BACKGROUND

The aim of this study was to analyze malformed petrous bones with computed tomography and to develop a radiologic score which can help to judge the indication for operative reconstructions.

METHODS

One hundred forty-two petrous bones in 71 patients with unilateral or bilateral microtia, atresia of the external auditory canal, and malformations of the middle ear were evaluated with high-resolution CT.

RESULTS

In 97% of patients with severe auricular dysplasia, there was dysplasia of the middle ear ossicles; in 70% the stapes was malformed. In 32% the oval window was occluded, and in 7% the round window. In 75%, the canal of the facial nerve was displaced, and 16% also showed abnormalities of the labyrinth. A close correlation between the malformation of the auricle and of the middle ear was not found.

CONCLUSIONS

High-resolution CT is necessary for the evaluation of malformed middle ears. Based on the abnormalities described, we propose a radiologic score for the assessment of malformed petrous bones. This consists of the following criteria: external auditory meatus, pneumatization of the mastoid and of the tympanic space, size of the tympanic space, facial nerve, vessels, malleus and incus, stapes, oval and round window. The graded points of each structure are added up to the score, which might range between 0 and 28. This score can help to judge the indication for reconstruction of the middle ear. In bilateral malformation we suggest a middle ear reconstruction of the better hearing ear if the score is greater than or equal to 15, and in unilateral malformation if it is at least 20. In patients with lower scores, we only suggest hearing aids.

Vein graft in stapes surgery

Sealing the opening of the oval window during stapes surgery is essential; it prevents postoperative complications, such as perilymph fistula and sensorineural hearing loss. In this small series of 269 cases with otosclerosis, tympanosclerosis, and congenital ossicular abnormality, vein grafting was used to seal the opening of the footplate. Hearing improvement after surgery was acceptable, and none had total hearing loss or perilymphatic fistula. World literature from the last half of this century on grafting the oval window is reviewed. Absorbable gelatin sponge (Gelfoam) seems to be causing more complications, so its use is highly discouraged. Temporalis fascia, fat, and perivenous loose areolar tissue have been used by different authors at different times in footplate surgery. The opening created in the oval window during stapes surgery must not be left uncovered.

[Obliterative otosclerosis]

In true (grade IV) obliterative otosclerosis, the limits of the oval windows are lost. The insertion of a prosthesis requires drilling and surgical ability. Thirty eight cases of the true obliterative otosclerosis operated in our Department between 1974 and 1992 have been reviewed. Only 6.2% of all the patients operated by us with the diagnosis of otosclerosis had true obliterative otosclerosis. The average preoperative gap in conversational frequencies was 39 dB. In general, the gap closure obtained (13 dB) was slightly lesser than that for otosclerosis. Reobliteration of the oval window may occur in this type of otosclerosis.

Transposition of the facial nerve in congenital aural atresia

It is generally recognized that surgery for congenital aural atresia is difficult. The success or failure of the operation is often directly related to the degree of development of the middle ear. In poorly developed middle ears, the facial nerve may overhang and conceal the oval window niche, making this area inaccessible to inspection, let alone manipulation. The criteria for transposing the facial nerve are; (1) the atresia must be bilateral, (2) there must be preoperative imaging evidence of a stapes and/or patent oval window, (3) there must be no large blood vessels feeding or draining the facial nerve, and (4) facial nerve monitoring must be available. Over the past 2 years, 6 of 94 patients undergoing surgery for atresia were operated with an intent to transpose the facial nerve in order to access the oval window. In all patients, it was impossible to see the oval window niche due to a displaced nerve. In four of six cases, the facial nerve was transposed. The ossicular chain was reconstructed with a total ossicular replacement prosthesis. In no case was there a postoperative facial paralysis or paresis. Facial nerve transposition allows a final chance of achieving serviceable hearing through surgery. The lack of facial nerve injury and the potential for hearing restoration make this procedure feasible in otherwise marginal or poor surgical candidates.

Prostheses for stapes surgery

A variety of different implants are available today for use by the otologic surgeon. All prostheses are well tolerated, and the risks of complication as a result of their implantation are comparable. The most commonly used prostheses are the wire-Teflon piston and the stainless steel bucket handle. Although the otologic surgeon has a wide variety of prostheses to choose from, most have a preference for one particular type. Results of hearing improvement following a successful stapedectomy is more a function of the surgeon's experience than of the type of prosthesis used. As James L. Sheehy, MD, so often says, "if a technique is working well for you, don't change for change's sake" (personal communication, 1994).

Comparison of endoscopic and surgical explorations for perilymphatic fistulas

A history suggestive of perilymphatic fistula (PLF) often prompts repeated tympanostomies to establish a diagnosis and perform a repair. Two patients having multiple previous explorations for perilymphatic fistulas were reoperated, comparing endoscopic and open surgical methods. A third patient with a history consistent with PLF also underwent dual assessment. Endoscopic exploration of the middle ear was performed through a myringotomy and, immediately after, by elevation of a tympanotomy flap. The endoscopic examinations were thorough yet revealed no evidence of perilymphatic fistula; however, the surgical approaches revealed pooling in the oval windows consistent with perilymphatic fistula. These findings were video documented. Recurrent and primary fistulas may be the result of artifact, such as injected anesthetic agents and transudates introduced during surgical explorations, which may interfere with an accurate diagnosis of perilymphatic fistula. Endoscopy of the middle ear is recommended as one method to minimize errors in diagnosis.

Postoperative recurrence of perilymphatic fistulas

Postoperative follow-up study of perilymphatic fistulas (PLFs) showed that recurrence of PLF was not rare and revision was sometimes needed to relieve the symptoms associated with leakage of perilymph. Of the 54 PLF patients surgically treated in our clinic, some sign or symptom of recurrence was found in 9 cases (17%). Vertigo accompanied by spontaneous or positional nystagmus was noted in all 9 cases, while only 3 complained of exacerbation of the existing hearing loss. Revision was indicated in 3 patients since they had no predisposition to spontaneous healing. Various etiological and underlying factors contributed to the incidence of recurrence. Careful operative procedures together with strict postoperative management are required for surgical treatment of PLF.

Impedance transfer: acoustic impedance of the annular ligament and stapedial tendon reconstruction in otosclerosis surgery

The resistance rebuilt around the lower tip of the piston must be the same as that created by the annular ligament of the stapes footplate. Otherwise, the threshold at which an acoustic or barotrauma is able to damage the membranes and hair cells of the inner ear will be lowered. The elasticity reestablished around the lower tip of the piston plays a part in the quality and quantity of hearing for the low frequencies up to 3 kHz. To protect the ear against acoustic traumas, an attempt to rebuild the stapedial reflex is proposed.

[Introduction to the surgery of the middle ear: general principles]

We study the basic guidelines of the middle ear surgery, having as target the recuperation of the anatomic functional integrity of ear. There are different important elements in the quality/quantity of the functional results as follows: The surgery technical method used. The actual pathology in the middle ear. The quality of eustachian tube function. The surgeon's experience and ability and several factors. We review the concept introduced by Wullstein called it tympanoplasty from 1952 till nowadays. Finally, we described the most frequent surgery procedures used in the daily practice.

Stapedectomy technique

This article reviews the evolution of the author's stapedectomy technique from total footplate removal with single loop wire prosthesis and Gelfoam seal to small fenestra stapedectomy with platinum ribbon piston prosthesis and blood seal. The author concludes that the microdrill is effective, safe, and cost effective for performing this procedure. Since using this technique, the author has had no cases of sensorineural hearing loss and few complaints of dizziness or vertigo.

Spontaneous perilymphatic fistula: electrophysiologic findings in animals and man

The case against the occurrence of spontaneous perilymphatic fistulas is presented. Electrophysiologic findings both in animals and in man suggest that small holes in either the round or oval window are not associated with any significant hearing loss. Removal of perilymph may cause some changes in the electrocochleogram that can be reversed when the perilymph is replaced. Tympanotomy surgery, especially when performed with the injection of local anesthetic solutions may result in transudates in the middle ear that are difficult to differentiate from perilymph leaking out from the inner ear. Perilymphatic fistulas were excluded by performing a posterior myringotomy under general anesthesia in 162 congenitally deaf ears. If fluid was present it was suctioned, and if no change occurred on the intraoperative electrocochleogram, it was concluded that no fistula existed. Based on the electrophysiologic findings and the clinical observations in over 240 ears, it was concluded that spontaneous perilymphatic fistulas do not exist. The author accepts that perilymphatic fistulas occur after surgery, especially after stapedectomy, and that they can occur after head injury or barotrauma. However, these should heal readily; persistent or intermittent fistulas are an otologic rarity.

Auditory performance of children with cochlear ossification and partial implant insertion

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.

Surgical management of perilymphatic fistulas: a Portland experience

A comprehensive review of our series of surgical perilymphatic fistula (PLF) repairs, as well as a review of published results from other otologists, suggested an unacceptably high rate of postoperative PLF recurrence. Some recurrences were related to specific events (i.e., coughing, strenuous activity, Valsalva-type maneuvers). However many cases had no apparent cause. Rather, the patients' symptoms recurred spontaneously, and at reoperation the graft was seen to have not "taken," suggesting graft failure rather than "patient failure." After a critical evaluation of current PLF surgical procedures and state-of-the-art concepts of wound healing, we developed a new surgical technique for PLF closure. Combining the use of laser graft-site preparation, an autologous fibrin glue "buttress," and a program of postoperative activity restriction, the new procedure allowed us to achieve statistically significant improvements in graft retention and surgical outcome, with recurrences dropping from 27 percent to 8 percent. In addition, complete resolution or significant symptomatic improvement occurred in 89 percent of patients with vertigo and/or dizziness and in 84 percent with disequilibrium. We conclude that this new surgical technique is an important addition to the otologic surgeon's arsenal for PLF management.

Perilymphatic fistula induced by barotrauma

The association between diving, barotrauma, and the production of perilymphatic fistula has been known for almost 20 years. Forty-eight cases of round and oval window fistulas following diving have been reviewed and essentially corroborate previous findings. Any patient with a history of diving and subsequent sensorineural hearing loss within 72 hours should be suspected of having a round or oval window perilymphatic fistula and surgical exploration and closure of the fistula should be undertaken. Patients who have a loss of hearing, vertigo, nausea, or vomiting following a decompression dive should be re-compressed and if symptoms do not clear, exploration should be performed. Surgical treatment should be executed as soon as possible after the diagnosis is suspected for the best possible results.

Positional audiometry in the diagnosis of perilymphatic fistula

Fifty-eight cases with a presumptive clinical diagnosis of perilymphatic fistula (PLF) are described with the results of a positional audiometric test designed to detect the presence of air in the cochlea. All patients underwent tympanotomy and observations of the middle ear are recorded together with the results of treatment. A definite leak was found in 33 cases and none in 25, but grafting of the round and oval window was performed in all but 10 cases. Pure-tone audiometry was performed before and after a 30-minute period of positioning the patient horizontally with the affected ear uppermost. A change in audiometric thresholds was noted in the group where a presumptive diagnosis of PLF was made, including some of those not found to have leaks at operation. However these changes were not observed in the positional tests of a group of 22 patients with hearing losses attributable to other causes. Also, an abnormal air-bone gap was noted in the PLF group compared with the other group. Although the original two-frequency criteria of earlier studies applied to the positional test did not predict the operative findings (leak or no leak), new data on frequency specific changes are presented. It is possible that fistulas at the oval window may be associated with positional threshold change at 500 Hz, and those at the round window with changes at 8 kHz.

Congenital anomalies limited to the middle ear

Congenital anomalies of the middle ear are occasionally encountered during surgery for conductive hearing loss and are unexpected in patients with no other deformities. We reviewed 12 such patients operated on at The New York Eye and Ear Infirmary from 1985 through 1989. Nine of the patients (75%) had unilateral conductive hearing loss whereas three (25%) had bilateral symptoms. One had bilateral congenital middle ear anomalies. Three patients (25%) had anomalies limited to the malleus and scutum. Five patients (47%) had agenesis of the oval window. After reconstructive surgery, 72% of patients had hearing improvement ranging from 13 to 38 dB. The etiology of these anomalies is discussed and their evaluation and surgical indications are presented.

[Bifenestration--a hearing-improving operation in severe ear malformations]

Bifenestration as an operation for hearing improvement is described in a case of congenital absence of the oval and round window. Besides the classical fenestration of the horizontal semicircular duct, an artificial round window was performed in the middle ear. Due to the acoustic resonance of the mastoid cavity, the resulting conductive loss in the higher frequencies was only 20-30 dB.

Repair of a cerebrospinal fluid perilymph fistula primarily through the middle ear and secondarily by occluding the cochlear aqueduct

A 35-year-old man had a 5-year history of fluctuating hearing loss in his only hearing ear. History and diagnostic tests indicated a perilymph fistula, a diagnosis subsequently confirmed by exploration. Primary and secondary repairs temporarily ameliorated symptoms. A spinal fluid to middle ear fluid pathway was identified by radioactive tracer. A patent cochlear aqueduct indicated on computed tomography scan was found and repaired through a posterior cranial fossa approach. Hearing was preserved, remaining relatively stable during the 2-year follow-up period.

Restoration of hearing with type V tympanoplasty

Type V tympanoplasty with fenestration of the oval window and protection of the round window in a residual hypotympanic cavity can be considered as the last-chance procedure for rehabilitation of hearing in ears with 'canal wall down' or other conditions. The review of 64 cases suggests that restoration of hearing can be adequate in the majority of cases.

Chondrogenic potential of tragal perichondrium: a cause of hearing loss following stapedectomy

Tragal perichondrium is a widely used tissue seal in the oval window following stapes surgery. Autogenous and easily accessible, it is a suitable substance to cover the vestibule in total stapedectomy, and to seal around the prosthesis in small-fenestra stapedotomy. The incidence of complications from the use of perichondrium in this manner is exceedingly low. We report a case where tragal perichondrium in the oval window resulted in the proliferation of cartilage. The cartilage displaced the stapes prosthesis, resulting in a conductive loss. Although the chondrogenic potential of perichondrium is known, we are not aware of other reports implicating this as a cause of failure in stapes surgery. The pertinent clinical and experimental literature regarding chondrogenesis is reviewed. This information suggests that the formation of cartilage from perichondrium in the oval window might be influenced by mechanical trauma and tissue orientation.

[Recurrence of perilymphatic fistula]

Recurrence of the perilymphatic fistula is not rare and may be a tough problem for surgical treatment. This is because a graft is usually applied on the ruptured window(s) from the middle ear and therefore the perilymphatic pressure directly acts on the graft. The recurrence may be caused by a technical failure, use of an unsuitable graft material, poor postoperative bedrest, trauma, increased inner ear pressure, etc. In our clinic, the recurrence occurred in 7 of 48 cases surgically treated. Vertigo accompanied with spontaneous or positional nystagmus was seen in all 7 recurrent cases, while only 2 of them complained of worsening of the existing hearing loss. Re-operation was carried out in two patients. In the first case, closure of the round window by the previous operation was found incomplete, and the perilymph leaked through the gap around the graft. In the second case, closure of the round window was complete, but perilymph leaked from the oval window. In order to prevent the recurrence, the operation should be carefully performed by using strong and adhesive tissue as a graft material, applying a glue between the graft and the inner ear window(s), and keeping strict postoperative bedrest.