Spiral ligament and stria vascularis changes in cochlear otosclerosis: effect on hearing level

OBJECTIVE

To investigate the effect of changes within the spiral ligament and stria vascularis on hearing in cochlear otosclerosis, we examined spiral ligament hyalinization, stria vascularis atrophy, and sensory hearing loss in cochlear otosclerosis and described changes in ion transport molecule expression.

STUDY DESIGN

Retrospective.

SETTING

Tertiary referral center.

PATIENTS

Thirty-two cochleae from 24 temporal bone donors with histologic evidence of cochlear otosclerosis, including spiral ligament hyalinization.

INTERVENTION

Audiography.

MAIN OUTCOME MEASURES

Measurements of spiral ligament width, stria vascularis, and bone-conduction thresholds were compared by the amount of hyalinization. Expression of the ion transport molecules Na,K-ATPase, connexin 26, and carbonic anhydrase II were assessed by immunohistochemical techniques.

RESULTS

Hyalinization most often involved the posterior basal turn (88%) and the posterior middle turn (27%). Spiral ligament hyalinization correlated significantly with stria vascularis atrophy in the posterior middle turn of the cochlea (rho = -0.63, p < 0.01). There was a trend toward a significant association in the posterior basal turn (rho = -0.31, p < 0.08). Bone-conduction thresholds at 2,000 and 4,000 Hz were significantly associated with the amount of stria vascularis atrophy (rho = -0.44, -0.40, p < 0.05). In addition, we observed decreased immunostaining for both carbonic anhydrase II with Type I fibrocytes and Na,K-ATPase with stria vascularis and Type II and Type IV fibrocytes of the spiral ligament in cochlear otosclerosis sections compared with normal cochlea. Na,K-ATPase staining within the stria vascularis was further decreased in the presence of spiral ligament hyalinization. No significant differences were seen with connexin 26 immunostaining. However, immunostaining results were somewhat inconsistent.

CONCLUSION

These data suggest that spiral ligament structure and function are essential for stria vascularis survival. In addition, dampened expression of ion transport molecules within the spiral ligament and stria vascularis may disrupt potassium ion recycling, resulting in loss of endocochlear potential and sensory hearing loss.

[Abnormalities in the tympanic cavity in otosclerotic patients]

The aim of the thesis is the analysis of the anatomical abnormalities and atypical conditions in the middle ear encountered during the surgery for otosclerosis and their influence for the course of the operation. These atypical conditions could result either from the congenital anomalies or from the disease itself.

MATERIAL AND METHODS

The material comprises 572 stapedectomies performed in ENT Department of the Pomeranian Academy of Medicine in Szczecin (Poland) between 1969 and 2004. Partial stapedectomy was performed with removal of the stapes crura and usually posterior part of the footplate.

RESULTS

Among 572 ears which underwent the operation different abnormalities in the tympanic cavity were found in 134 cases (23,4%). These included: narrowed oval window niche in 71 cases, stapes anomalies in 46 cases, obliterative otosclerosis in 20 cases, red otospongiosis of the stapes in 9 cases, increased perilymph pressure in 7 cases, malleus and incus bony fixation in 3 cases. The presented abnormalities were the reasons of many failures at the time of the operation. While in the 438 ears with normal anatomical status in the tympanic cavity failures during the operation occurred in only 6 cases (1,4%), in the 134 ears with such abnormalities failures happened in 33 cases (24,6%). The most frequent failure - 20 cases - was premature mobilization of the stapes followed by other consequences. In the other 9 cases the operation was discontinued for different reasons. Another failure was the floating footplate in 2 ears, facial nerve paresis in 1 ear and incus subluxation also in 1 ear. In a few cases in which the operation was stopped the successful stapedectomy was performed at the 2nd stage. Only in 3 ears the stapedectomy was totally given up what makes 0,5% out of the 572 ears operated on.

Stapesfixation bei Kindern

BACKGROUND AND OBJECTIVE

The audiometric results after stapes surgery in children with isolated stapes footplate fixation were reason enough to analyze intraoperative findings and surgical procedures.

PATIENTS/METHODS

A total of 438 stapes surgeries were performed in the years 1985-2000, and a retrospective analysis was made of the anamnestic data, intraoperative findings and audiometric data from 12 children with isolated fixation of the stapes footplate. The average age of the children when operated was 10.2 years (the youngest was 7 and the eldest 13). A loss of hearing had set in 5 years earlier.

RESULTS

Taking the anamnestic data and the intraoperative into account, otosclerosis was found in 5 children. One child had a narrow oval window niche, in a further six children a congenital fixation of the stapes footplate was evident. Only 58% (n=7) of the 12 children operated showed acceptable postoperative hearing results. The best hearing results were found in children with juvenile otosclerosis. In three of six children with congenital stapes fixation, a worsening of both bone and air conduction was evident. The average conductive hearing loss was 30 dB at 1, 2 and 4 kHz.

CONCLUSIONS

When explorative tympanotomy is indicated, a thin-layer CT scan of the temporal bone should be made to assess the risk of a liquor pressure labyrinth developing.

Otospongiose cochléaire et pseudo-quatrième tour de cochlée

OBJECTIVE

To describe different sequences on magnetic resonance imaging (MRI) in otosclerosis with peri-cochlear involvement.

METHOD

MRI T1 and T2 sequences with T1 gadolinium injection and computed tomography (CT) scans with millimetric slices on axial and coronal views were obtained. The diagnosis of bilateral otosclerosis was confirmed by surgical exploration.

RESULTS

On the CT scan, there was a fourth turn of the cochlea which appeared on the MRI T1 sequence with an intermediate signal and on the T2 sequences with a high intensity signal. After gadolinium injection, there was signal enhancement, suggestive of active otospongiosis. On the CT scan, there was another lesion in front of the cochlea with endosteal involvement. This was no however visible on the MRI, even after gadolinium infusion, in accordance with inactive otospongiosis.

DISCUSSION

We reviewed the literature concerning MRI and results in otosclerosis.

CONCLUSION

MRI of the labyrinth with T1 sequences and gadolinium injection can be contributive to the diagnosis of otosclerosis to differentiate inactive from inactive otospongiosis. However, prospective studies must be conducted to confirm this hypothesis.

Temporal bone density measurements using CT in otosclerosis

OBJECTIVE

To assess the bone density around the bony labyrinth in otosclerosis patients and to compare it to that of a control population.

MATERIAL AND METHODS

This was a prospective case-control study. Ten patients with otosclerosis (mean age 42 years; range 24-55 years) and 33 control patients with vestibular schwannoma (mean age 46 years; range 20-71 years) were included. All patients underwent a clinical examination, audiometry and a CT scan comprising axial and coronal views of both temporal bones. In the otosclerosis group, audiometry showed unilateral involvement in six patients and bilateral hearing loss in four. The bone density was measured at the fissula ante fenestram (FAF) and at five other anatomical points on the bony labyrinth.

RESULTS

In the control group, the bone density was similar at the six anatomical points. In the otosclerosis patients, the mean bone density at the FAF was lower than that in control patients (1649+/-99.1 vs 2049+/-13.4 HU; p < 0.01). For patients with FAF bone densities < 2000 HU, a correlation was observed between hearing threshold and FAF bone density.

CONCLUSION

FAF bone density appears to be a good indicator of disease progression, and could serve as a follow-up and prognostic parameter.

A new approach for malleus/incus fixation: no prosthesis necessary

OBJECTIVE

To describe a novel approach to manage malleus/incus fixation.

STUDY DESIGN

Retrospective review of 363 patients with conductive hearing loss operated on since 1996.

SETTING

Academic tertiary referral center.

PATIENTS

Three hundred sixty-three patients with conductive hearing loss, an intact tympanic membrane, and without history for chronic infection underwent middle ear exploration. Three hundred forty-three had otosclerosis and underwent laser stapedotomy; the remaining 20 patients had laser release of their malleus/incus fixation.

INTERVENTION

Twenty patients are presented in this paper. Nineteen patients were diagnosed with malleus fixation before surgery. One patient had a total perforation and mobility of the ossicular chain was not verified preoperatively. This patient was, intraoperatively, noted to have complete ossicular fixation. Conductive hearing loss was identified using audiometry and tuning forks. Nineteen of the 20 patients had the diagnosis confirmed using micropneumotoscopy and noting immobility of the malleus. A transcanal approach was used, and the malleus/incus fixation was released using a laser. This space was expanded upon using a drill. A 1.5-2.0 mm space was created where the ossicular fixation existed, thereby reducing the likelihood of refixation.

MAIN OUTCOME MEASURE

Audiometric studies before and after intervention were compared. One to seven years of follow up are provided.

RESULTS

Preoperative air-bone gaps ranged from 18 dB to 51 dB and averaged 33 dB. Postoperative air-bone gaps ranged from 1-36 dB and averaged 13 dB. No patients have experienced refixation. There were two complications: one perforation requiring a tympanoplasty and one patient sustaining a 20 dB high-frequency sensorineural loss, most likely secondary to inadvertent drill contact to the ossicular chain.

CONCLUSION

When fixation of the malleus and/or incus is found, treatment options exist. A common technique involves removal of the incus and head of the malleus and reconstruction with an incus interposition or a partial ossicular prosthesis. Another technique proposed by the senior author (M.D.S.) is maintenance of the normal anatomy and use of the potassium-titanyl-phosphate laser and drill to free the ossicles and widen the epitympanum. This series shows successful closure of the air-bone gap with this technique.

Ciliary count in chronic suppurative otitis media: comparative quantitative study between mucosal and squamous types using scanning electron microscopy and image analysis

The objective of this study was to prove ciliary destruction in the middle-ear mucous membrane in cases of chronic suppurative otitis media (CSOM) and to compare both types of chronic suppurative otitis media with regard to the degree of ciliary destruction and ciliary count using objective quantitative techniques. The mucosa of the anterior mesotympanum over the promontory was sampled in 10 patients with mucosal CSOM and in another 10 patients with squamous type CSOM. Specimens were examined by scanning electron microscopy in combination with image analysis software techniques in order to study the cilia under higher magnifications and to calculate the ciliary area. Five patients with otosclerosis, no history suggestive of otitis media and normal ear drum appearance served as controls. Samples were taken and studied at the Faculty of Medicine of Cairo University. CSOM was found to be associated with significant ciliary destruction and this was more evident in the squamous type than in the mucosal type.

[Perilymphatic effusion as a complication of otosclerosis]

INTRODUCTION

Stapes gusher means the leakage of perilymphatic liquid when opening the perilymphatic cistern. The perilymphatic liquid with a high pressure gushes with a great flow out of the cistern when the stapedotomy is executed. Otosclerosis surgery sometime brings to light abnormal contact between the inner ear and the sub-arachnoidian spaces in patients who didn't presented ear malformations. It's a very rare event (1/1000) which is different from a much more common and more moderate form of perilymphatic liquids high pressure (1/200). About 4 clinical observations, we compared our experience with other authors in specialist reviews.

PURPOSE OF THE STUDY

About four observations, we confronted our experience with that of the literature.

MATERIAL AND METHODS

Retrospective study between 1971 and 1998. It was about 3 males and 1 female, without antecedent except one of them who had been operated 5 years before for the opposite ear without gusher but without good audiometric result. They presented a conductive deafness with no answer of the stapedial reflex. We had 4 geysers during the platinotomia which were sealed with some connective tissue.

RESULTS

Two patients had a post operative complete sensory hearing loss, one, a sensitive decline of the conduction thresholds (average 50 dB), the last one kept his bone conduction level with a mild sensory hearing loss. The most recent case had a scanner preoperatively which had not shown abnormality except for the focus of otosclerosis.

DISCUSSION

Perilymphatic gusher is an unpredictable event that can not be diagnosed before the surgery, nether with clinical facts nor radiological elements. This involves serious consequences concerning not only the continuation of the surgical operation and the prognostic of the hearing but also concerning the danger of secondary meningeal infections. The best way to proceed in case of favourable cases consists in fitting the ossicular prothesis into the stapedotomy, when it's not to wide. Pieces of muscle can be used in some cases, taped on with biologic glu. Various techniques are used to lower the pression of the cerebrospinal liquid: hypertonic solutes, diuretic drugs, lumbar diversion. In all cases, it is necessary to start a wide spectrum antibiotic treatment and a vaccination against pneumococcis.

CONCLUSION

The surgeon has to know all the option of the treatment when confronted with this situation in order to try to avoid tricky defect of the inner ear.

Clinical relevance of the distance between the cochlea and the facial nerve in cochlear implantation

HYPOTHESIS

To elucidate possible mechanisms of facial nerve costimulation after cochlear implantation that are supposed to result from the close cochlea to facial nerve contact.

BACKGROUND

One of the postoperative complications of cochlear implantation is facial muscle twitching, which has preferentially been found in otosclerotic patients. It impairs hearing benefits because of deactivation of electrodes and can still not be adequately prevented.

METHODS

A total of 13 temporal bones were dissected to quantify where the labyrinthine portion of the facial nerve is closest to the scala tympani, the placement site of the cochlear implantation electrode array. After the typical operative procedures to find out the number of electrodes lying closest to the facial nerve were performed, a cochlear implantation array was inserted into four specimens. The clinical records of 14 otosclerotic patients were investigated to correlate these results with the position of in vivo deactivated electrodes.

RESULTS

The closest distance between the scala tympani and the nerve was only 0.33 mm (+/-0.14). On average, after insertion of 23 electrode resp. marking rings, the facial nerve was reached. This is clinically the position of most frequently deactivated electrodes to prevent postoperative facial nerve costimulation.

CONCLUSIONS

These investigations support the hypothesis that a direct current spread at the site of the facial nerve crossing the cochlear basal turn is most likely the reason for postoperative facial muscle twitching facilitated in otospongiotic bone. Prevention could therefore be achieved by cochlear implantation designs and surgical techniques that take into consideration the site of closest contact.

Neuroplasticity of auditory cortex after stape surgery for otosclerosis: a magnetoencephalographic study

Aim of the present study was to investigate the tonotopic reorganization of the primary auditory cortex in otosclerotic patients following functional stapedioplasty. Characteristics of auditory cortex activation have been evaluated in a series of 10 otosclerotic patients before and after surgery. In these patients, a magnetoencephalographic recording of evoked magnetic fields has been performed by means of tone-burst monoaural stimulation with frequency octaves between 250 and 2000 Hz. Brain topography of cortex response generators (wave N100m) in patients with otosclerosis has been compared with that observed in a control group of 10 healthy subjects: changes before and after surgery have also been correlated with the functional result as far as concerns improvement in hearing. A significant reduction has been observed in the cortical tonotopic extension in response to the acoustic stimulus in patients "pre-surgery" in comparison with controls: after surgery, tonotopic mapping showed an increase, dimensions becoming comparable to those in control subjects. This increase in size was found to be significantly correlated with duration of the post-operative period. Data emerging from the present study suggest that the cortical auditory areas in man are involved in a "plastic" functional reorganization following changes in the receptor or peripheral deprivation. Reduction in the cortical tonotopic mapping resulting from prolonged lowering of auditory "input" is modified by reorganization of the cortex after the recovery of auditory function: this process occurs over a period of a few weeks.

Why is otosclerosis of low prevalence in Japanese?

OBJECTIVE

This study aimed to clarify the reasons why clinical otosclerosis, a very common disease among Caucasians, is not prevalent among Japanese.

STUDY DESIGN

The incidence, site, activity, and volume of otosclerotic foci were examined in 1011 temporal bone sections from 507 Japanese individuals.

SETTING

This study was prepared at the temporal bone laboratory, Fukushima Medical University, Fukushima.

RESULTS

Otosclerotic foci were observed in 2.56% of individuals and in 1.48% of the ears. The most common site of involvement was anterior to the oval window region, but this was only in 38.9% of the ears with otosclerotic foci. The otosclerotic foci were not involved in the stapediovestibular articulation or the endosteal layer of the otic capsule in any ears. An active change of the otosclerotic focus was seen in 33.3% of ears with otosclerosis. The volume of otosclerotic foci at the site anterior to the oval window region was less than 0.8 mm3 in 5 out of 7 ears.

CONCLUSION

The incidence of histologic otosclerosis among Japanese seemed to be almost the same as that among Caucasians. Three reasons why clinical otosclerosis was not as prevalent among Japanese as among Caucasians are suggested: low incidence of involvement of foci anterior to the oval window, low activity, and small lesion without involvement of the footplate and/or membranous labyrinth of the inner ear.

Histologic changes on stapedial footplate in otosclerosis. Correlations between histologic activity and clinical findings

OBJECTIVE

To quantify the relationship between the stage of histologic changes of the stapedial footplate in otosclerosis and the magnitude of preoperative hearing loss, tinnitus, vestibular disorder, and postoperative improvement of hearing.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

The study included 97 patients (ears) (69 female and 28 male patients), with conductive or mixed hearing loss who were operated on for otosclerosis. The criterion for including a patient in the study was otosclerosis established by tympanoscopy and confirmed by histologic examination of a piece of the stapedial footplate.

MAIN OUTCOME MEASURES

By the histologic features of the stapedial footplate fragments, the stage of the otosclerotic lesion was classified as spongiotic, fibrotic, or sclerotic. The patients were carefully matched for sex, age, duration of hearing impairment, presence of tinnitus, and vestibular symptoms. Preoperative and postoperative air-conduction and bone-conduction thresholds were calculated as an average of four frequencies (0.5, 1, 2, and 4 kHz). Analysis was subsequently carried out on the preoperative and postoperative air-bone gap and bone-conduction threshold improvement.

RESULTS

With regard to the histologic stage of otosclerotic lesions, tinnitus and vestibular disorders were present more frequently in patients with the sclerotic type of lesion. The type of otosclerotic lesion had no significant influence on the mean preoperative air-conduction threshold, bone-conduction threshold, and air-bone gap or on postoperative air-conduction threshold and bone-conduction threshold, but the postoperative air-bone gap was higher in patients with the fibrotic type of otosclerotic lesion and was highest in patients with the spongiotic type of otosclerotic lesion (p < 0.01).

CONCLUSIONS

Tinnitus, vestibular disorders, and better postoperative closure of the air-bone gap are present more frequently in patients with a sclerotic type of otosclerotic lesion on the stapedial footplate.

Hearing results in stapes surgery using two different prosthesis

AIM OF THE STUDY

Evaluation of hearing results after implantation of a fluoroplastic-platinum piston (FP) and of a titanium piston (T) with a shaft diameter of respectively 0.6 mm and 0.4 mm, in cases of otosclerosis requiring stapedotomy.

MATERIAL AND METHODS

Pre-operative and post-operative hearing results obtained after primary stapedotomy by implantation of 30 FP and 30 T performed by the same expert author (C.Z.) were reviewed. In each patient we evaluated pre- and post-operative auditory thresholds, as recommended.

RESULTS

All patients of both groups showed a significant air-bone gap (ABG) improvement for all frequencies after surgery ( P < 0. 001). Post-operative ABG comparison between the two groups showed a better ABG for lower frequencies in the FP group and for higher frequencies in the T group, but the difference was not significant. No post-operative complications, including sensorineural hearing loss, were found. Bone conduction improvement was better in the FP group than in the T one and this difference was statistically significant at 1000 and 2000 Hz. There was no statistically significant difference in the post-operative outcomes between the two prosthesis. Better results of FP for lower frequencies suggest that an increase in diameter of the prosthesis results in a greater improvement in the hearing threshold at low frequencies, while a decrease of diameter results in a greater improvement in the hearing threshold at high frequencies, as indicated by previous international studies.

CONCLUSION

Our data shows that titanium piston is a as good as fluoroplastic piston in stapes surgery for otosclerosis.

The anterior and superior malleal ligaments in otosclerosis: a histopathologic observation

HYPOTHESIS

The aim of this study was to assess, in otosclerosis, whether the anterior and superior malleal ligaments show histologic changes that can lead to reduced malleal mobility and eventual fixation, and also to evaluate whether these changes are related to the degree of histologic otosclerosis.

BACKGROUND

Fixation of the malleus seems to be one of the most controversial clinical entities in the acquired condition of otosclerosis. It has even been postulated that persistent conductive deafness, or progression of conductive deafness after initial improvement after stapedotomy, could be due to unsuspected malleus fixation.

METHODS

Fifty eight temporal bones with known otosclerosis and 43 normal temporal bones were selected. In addition, 10 temporal bones of fetuses and children were also studied. Otosclerosis of the footplate and otic capsule was graded as none, mild, moderate, and severe. The histologic changes in the ligaments also were graded from none to severe.

RESULTS

The median ages of patients in the otosclerotic and normal groups were 62 and 60 years, respectively. In the anterior malleal ligament of the otosclerotic bones, 10% mild (+), 60% moderate (++), and 30% severe (+++) degrees of hyalinization were observed. In the anterior malleal ligament of the nonotosclerotic bones, 14% showed no hyalinization, 24% had only a tinge of hyalinization (minimal), 51% had mild (+) hyalinization, and 11% had moderate (++) hyalinization. Superior ligament hyalinization appears to be related to the severity of anterior ligament hyalinization. The severity of otosclerosis in the footplate or the otic capsule did not appear to be related to the severity of hyalinization.

CONCLUSION

From this study, it is apparent that otosclerotic bones have a significantly high incidence of hyalinization of the anterior malleal ligament. This seems to be related to the duration rather than the severity of otosclerosis. It is important to properly evaluate malleal mobility during all stapes surgery.

Ossicular fixation caused by bone dust after saccus decompression surgery

HYPOTHESIS

To highlight the clinical and histologic features of ossicular fixation produced by bone dust during mastoid surgery.

BACKGROUND

Bone dust deposition in the middle ear may occur during temporal bone surgery, but the ossicular fixation that may result from it remains underreported.

METHODS

A case is reported of delayed conductive hearing loss after saccus decompression surgery resulting from ossicular fixation by bone dust deposition.

RESULTS

Six months after the initial surgery, the patient experienced a 45 dB conductive hearing loss. The findings on second-look tympanotomy were stapes fixation and round window niche occlusion by newly formed tissue. Histologic examination of the latter showed fibrosis and new bone formation in reaction to particles of bone dust. New bone formation is a frequent concomitant of fibrosis in the middle ear and is probably not a growth from the bone dust.

CONCLUSION

The use of high-speed drilling of bone in temporal bone surgery carries the risk of bone dust particle deposition in the middle ear. Measures are discussed that can be used to prevent this complication.

Magnetic resonance imaging and high-resolution computed tomography in the otospongiotic phase of otosclerosis

Otosclerosis very often leads to severe hearing loss in a chronic progressive manner. In the first phase of the disease, otospongiosis causes an inflammatory osteolytic process in the osseous labyrinthine capsule. In the cases reported here, this osteolytic process was pronounced in the osseous capsule of the cochlea. High-resolution CT and MRI showed the precise localization and stage of this inflammatory-osteolytic process in the petrous bone, while scintigraphy confirmed the diagnosis.

[Clinical aspects of a virtual operating room for the prediction of operative interventions in some disease of the middle ear]

Clinical aspects of creating a software system for simulation and prediction of operative interventions and hearing function changes are considered. The system will make simulation and prediction transparent and convenient for the user. The technical challenge is to create mediation languages which enforce rigorous mathematical computation while supporting intuitive behaviour. The prevalent textual interface of command lines and pull-down menus is replaced by physical behaviour within an environment. The system is based on new possibilities of computer-integrated environments for problem solving such as virtual environments and it will be presented in a form of a virtual operating room. The following aspects are taken into consideration: a model of the middle ear, database for existing methods of operative interventions, x-ray and computed tomography imaging of the temporal bone, determination and localization of otosclerosis foci, modeling and determination of acoustic parameters for transplantation materials, simulation and prognosis of potential complications.

Correlations between virtual endoscopy and otoendoscopy of the retrotympanum

The aim of this study was to examine the anatomical landmarks of the retrotympanum using two different techniques, virtual endoscopy (VE) and fiberoptic endoscopy, and to correlate the results furnished by the two methods. Ten otosclerotic patients who were due to undergo stapedectomy were scanned using high-resolution spiral CT. Selected CT datasets were processed with Navigator 2.0 software to obtain virtual endoscopic views of the retrotympanum. Subsequently, during the surgical procedure, fiberoptic endoscopy was performed with 2.7-mm 0 degrees and 30 degrees rigid endoscopes. The ability of the two imaging methods to identify specific anatomical structures was then compared. In all cases the pyramidal eminence, pyramidal crest and sinus tympani were clearly identified in both VE images and otoendoscopy recordings, while fiberoptic endoscopy seemed to be less satisfactory than VE for studying the facial sinus, sinus of Proctor and fossula of Grivot. The two techniques proved to be equally sensitive for visualizing the ponticulus and subiculum, while the stapedius tendon could be visualized only by means of fiberoptic endoscopy. Overall, VE imaging appears promising for rendering important anatomical details of the retrotympanum, allowing identification of osseous landmarks and exploring recesses that are difficult to visualize via otoendoscopy.

[Late deterioration in bone conduction after stapes surgery: a retrospective analysis]

In spite of the well-consolidated technique that otosclerosis surgery has built up, there are several aspects that have yet to be satisfactorily explained. One of these is the greater long-term "vulnerability" that appears to characterize an ear that has been operated on compared to a healthy one. In searching for a feasible explanation of this phenomenon and its therapeutic implications, a retrospective analysis of 26 cases was carried out on patients who had been operated between 1966 and 1995 and had come to our attention between 1989 and 1999 due to a rapid, late deterioration in bone conduction. Short-term treatment was pharmacological and surgical in 19 cases and exclusively pharmacological in 7 cases. The analysis of the results of therapy was based on an evaluation criterion of PTA (250-4000 Hz) > 5 dB, calculated on the basis of the bone conduction threshold values. Possible prognostic factors were searched for by means of a multivariate analysis that took as its dependent variable the bone conduction hearing threshold following therapy and as independent variables the age, gender, monolaterality of the otosclerosis ascertained, a positive medical history for analogous phenomena and for previous surgical revision, concomitant vertigo, the time that had elapsed between initial treatment (operation) and deterioration, the technique adopted during the first operation, the extent of the rapid deterioration, the audiometric characteristics at the outset of treatment for the acute episode, the time that had elapsed between deterioration and treatment, the type of treatment, possible reopening of the oval window, and intraoperative findings of a perilymphatic fistula. In the 7 cases managed with pharmacological therapy alone, improvement was seen in 3 cases while the condition remained unvaried in 4 cases; surgical revision (which in 5 cases enabled the presence of a fistula to be ascertained) associated with pharmacological therapy brought improvement in 4 cases, worsening in 4 cases, and no variation of the condition in 11 cases. The only prognostic factor detected, of an unfavourable nature, was the presence of anacusis upon examination. The results obtained do not enable unambiguous conclusions to be drawn: it may in any case be inferred that, at least in certain particular cases, above all when a false cochlear deterioration or the presence of a fistula is suspected, an "aggressive" therapeutic approach may be justified.

Etiopathogenesis of otosclerosis

Otosclerosis is a frequent cause of nonsyndromic hearing loss which affects exclusively the human temporal bone. Various etiopathogenetic hypotheses have been proposed. The major hypotheses considered are genetic factors, immunologic factors and viral infection. Since the familial incidence of otosclerosis is known a recent genetic analysis has given evidence of three otosclerosis genes (OTSC1-3). Mutations in the collagen gene COL1A1 have been found in one large family with several cases of otosclerosis. Concerning an immunologic etiopathogenetic process, the presence of serum antibodies against collagen II and IX in patients with otosclerosis confirms the hypothesis of a collagen autoimmune mechanism. Finally as a possible cause of this chronic inflammatory disease morphologic and biochemical investigations have revealed a measles virus association. In conclusion, various etiopathogenetic factors may contribute to the genesis of otosclerosis.

Reparative granuloma seen in cases of gold piston implantation after stapes surgery for otosclerosis

OBJECTIVE

to determine the occurrence of the unusual side effect of a reparative granuloma after the implantation of a pure gold piston in cases of otosclerosis.

STUDY DESIGN

a retrospective case review study of 475 stapes operations with a pure gold piston.

SETTING

Department of Otorhinolaryngology of the University of Amsterdam, The Netherlands and the HNO clinic in Luenen (Brambauer) in Germany.

PATIENTS

four hundred and seventy five patients (328 women, 147 men, average age: 45.2 years), who clinically and per-operatively had otosclerosis, underwent a stapedotomy using a pure gold piston prosthesis. Therapeutic intervention: in cases of suspicion of a reparative granulomas or those cases that did not have improvement of the hearing after the stapedotomy, a re-operation by transcanal approach was performed.

RESULTS

in seven cases a reparative granuloma was diagnosed by this revision surgery. The postoperative incidence of these granulomas following stapedotomy using the pure gold piston turned out to be 1.5%.

CONCLUSION

reparative granulomas can occur after stapedotomy with a pure gold stapes piston although the incidence is low. The role of grafting material to seal the oval window niche and the treatment of these reparative granulomas following stapes surgery are discussed.