Posterior Auditory Canal Wall Research Articles

Reconstruction of the mastoid using a titanium cage.

Evaluate reconstruction of the posterior canal wall, including the mastoid cavity after canal wall-down cholesteatoma removal. A titanium mesh metal cage was used to rebuild the posterior auditory canal wall and mastoid cell system in 12 patients undergoing cholesteatoma removal. The cage was then covered with pieces of cartilage to reconstruct the soft tissue surface. All reconstructions epithelialized completely. There was no denudation of the titanium material or signs of extrusion. Recurrences of cholesteatoma occurred twice according to the condition of the underlying disease, not related to the material. The titanium cage showed good biocompatibility in the middle ear space and the potential for rebuilding the mastoid cell system, making it a versatile tool for primary cases with large defects and in revision cases where soft tissue with cartilage-only reconstructions failed. Reconstruction of the posterior canal wall and mastoid by means of a titanium cage can be used in situations where adhesive tensions need a more stable construction and support of the posterior canal wall.

The Safe Zone of Posterior Semicircular Canal Resection in Suboccipital Retrosigmoid Sinus Approach for Acoustic Neuroma Surgery

The aim of the study was to find the safe zone of posterior semicircular canal resection that can avoid structure damage in suboccipital retrosigmoid sinus approach for acoustic neuroma. One hundred twenty subjects (72 male and 48 female subjects) were involved in this study anonymously. Five parameters are measured in computed tomography: L1 is the line that goes through the common bony crus and parallel to the plane that contains posterior semicircular canal at axial plane. L2 is the middle sagittal line at axial plane. A is the point of posterior wall of the internal auditory canal at the level of the common bony crus. B is the intersection point of L1 and posterior wall of auditory canal. L3 is the line that goes through the plane that contains posterior semicircular canal at coronary plane. L4 is the middle sagittal line at coronary plane. C is the common bony crus. D is the ampulla. E is the most posterior point of posterior wall of auditory canal at the plane that goes through the posterior semicircular canal. The angle between L1 and L2 was 41.76 (SD, 5.64) degrees on the right and 43.40 (SD, 5.25) degrees on the left (P = 0.003). The distance between A and B was 0.59 (SD, 0.13) cm. The angle between L3 and L4 was 16.57 (SD, 6.51) degrees on the right and 17.57 (SD, 6.98) degrees on the left (P = 0.017). The distance between C and D was 0.60 (SD, 0.05) cm. The distance between E and line CD was 0.48 (SD, 0.09).

Temporary removal of the posterior bony canal wall with reconstruction using microplate osteosynthesis in cholesteatoma surgery: a case series and description of the technique

We describe the surgical technique of temporary removal of the posterior auditory canal wall with reconstruction and report the outcome of using this technique as a treatment method for cholesteatoma in a case series. In 32 cases of cholesteatoma surgery a technique of temporary removal of the posterior bony wall was applied. During primary surgery the posterior auditory canal wall was removed using an oscillating saw. For the purpose of reconstruction, the canal wall was repositioned and fixed using two titanium microplates (n = 26). In case the canal wall could not be reconstructed with osteosynthesis, either glass-ionomeric cement (BioCem™) was used for fixation (n = 4) or fibrin glue (Tissucol™) (n = 2) to support the posterior wall. The outcome includes the healing process in the first postoperative month, the absence of residual or recurrent disease and the successful reconstruction of the posterior auditory canal wall as evaluated during second-look surgery. When microplates where used, we saw healing problems of the canal skin in about 4% of patients. Recurrent cholesteatoma was found in 4 cases (14%), residual cholesteatoma in 8 ears (25%). In the osteosynthesis group, successful reconstruction was achieved in 25 patients (96%). In 3 out of 4 patients of the glass-ionomeric cement group (75%) excessive granulation tissue developed with extensive bony lysis. Temporary removal of the posterior auditory canal wall offers potential for the control of cholesteatoma. Our first results suggest that osteosynthesis allows for a good anatomical and functional reconstruction.

Navigationsgeführte minimal-invasive Cochlea-Implantation - Untersuchungen am humanen Felsenbein

The accuracy of navigation systems can be improved significantly by using high-resolution flat panel-based Volume Computed Tomography (fpVCT) so that new surgical therapeutic concepts become feasible. A navigation-guided minimally-invasive cochleostomy places highest requirements on the accuracy of intraoperative navigation. A flat-panel Volume Computed Tomograph (fpVCT) was used to scan four human temporal bones. The isometric voxel size was 200 microm. The preoperative planning was used to define an optimized drilling channel from the mastoid surface to the round window niche and the scala tympani providing a safety margin to critical anatomical structures such as facial nerve, chorda tympani, sigmoid sinus and posterior wall of auditory canal. The canal was drilled hand-operated with a navigated drill following the previously planned trajectory. Afterwards the drilled canal was imaged by fpVCT. Conventional dissection including mastoidectomy and posterior tympanotomy assured correct localization of the cochleostomy. Path planning took an average of 54 minutes (range 35-85 minutes). Installation took an average of 16 minutes (range 14-19 minutes). The drilling procedure itself took an average of 7.75 min (range 5-12 minutes.) The RMSE-values varied between 0.1 and 0.2 mm (Table 1). All four specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in one specimen--this was preoperatively planned as a narrow facial recess was encountered. The time needed for planning and system-installation could be reduced continuously. This feasibility study demonstrates that using current image-guided surgery technology in combination with fpVCT allows drilling of a minimally invasive channel to the cochlea with loco typico cochleostomy. The necessary accuracy of intraoperative navigation can be achieved by use of fpVCT (technical accuracy between 0.1 and 0.2 mm). Our results demonstrate the feasibility of a navigation-guided minimally-invasive cochleostomy loco typico. While we are enthused by this preliminary work, we recognize the barriers which exist in translation to clinical application. These include surgical issues (e.g. control of unexpected bleeding) and electrode issues (e.g. development of insertion tools).

Surgical classification of variations in the anatomy of the sigmoid sinus

Objective Analyze the variability of anatomic relations between the sigmoid sinus and other surgical landmarks within the mastoid cavity to establish a classification of sinus location to facilitate surgical planning. Study design A descriptive study of surgical landmarks using 96 temporal bones from the Temporal Bone Laboratory at the Department of Otorhinolaryngology, Valle University at Cali, Colombia. Methods A dissection simulating a canal wall-up mastoidectomy extended to include exposure of the facial recess, epitympanum, and sigmoid sinus was performed on 96 adult disease-free temporal bones. Seven standard measurements were taken on each bone between the sigmoid sinus and other structures in the mastoid cavity. All data were analyzed using Epi-Info 2000. Results This parametric study was consistent with three classes of anatomic variations in the location of the sigmoid sinus (type 1, type 2, and type 3) based on a Gaussian distribution of the seven variables. Conclusions Variability in the anatomic location of the sigmoid sinus in the mastoid cavity is common and has surgical relevance. Significance This classification will help to rapidly identify the sigmoid sinus relationship within the mastoid cavity and to use the sigmoid sinus as a landmark during ear surgery in those cases in which traditional landmarks, such as the posterior auditory canal wall or the semicircular canals, are destroyed by a pathologic process.

Fixation der temporär entfernten hinteren Gehörgangswand mit Plattenosteosynthese: Eine neue Technik

Temporary removal of the posterior external ear canal wall allows excellent exposure of the middle ear and epitympanum without the negative sequelae of a cavity as can occur after canal-wall down procedures. Safe fixation of the bony canal wall, however, has not always been possible with a risk for prolonged healing and bone necrosis. A new technique permits rigid internal fixation of the posterior canal wall. A titanium miniplate of 10 holes length commonly used for orbital rim surgery is adapted to the cortical surface of the mastoid just posterior to the external ear canal. Six holes for 1.3 mm screws are drilled into the cortical bone: two screws behind the ear canal, two screws on the temporal line, and two on the mastoid tip. All fixation material is then removed and a mastoidectomy is carried out with preservation of the cortical bone for the screws. The external ear canal skin, which has been incised previously near the fibrous annulus with lateral extensions, is mobilized laterally using a newly designed retroflected microraspatory. This creates a vital skin flap that might be essential to avoid bone necrosis. No other skin incisions are needed in the canal. The posterior bony canal wall is cut using an oscillating saw Osseoscalpel, secured by facial nerve monitoring. After middle ear surgery and tympanoplasty have been completed, the canal wall is repositioned and fastened precisely in its place with rigid internal fixation allowing a secure stabilization. This new technique has proven to be safe and reliable on the first five patients. There has been no bone necrosis within an observation period of 18 months. Rigid internal fixation is an alternative technique to safely readapt the posterior auditory canal wall.

Management of Vestibular Schwannomas (Acoustic Neuromas): Radiological Features in 202 Cases-Their Value for Diagnosis and Their Predictive Importance

OBJECTIVE: Tumor-induced bony and soft tissue findings might reflect, in part, the biological characteristics of vestibular schwannomas and could predict clinical findings. In addition, the role of the individual anatomic conditions of the posterior fossa is of interest to the surgeon. METHODS: Of 1000 vestibular schwannomas treated surgically at the neurosurgical department at Nordstadt Hospital, 202 cases, which were consecutively investigated at the same computed tomography (CT) unit and using the same technique (high-resolution CT at bone windows before and after surgery, contrast-enhanced high-resolution CT before surgery, and native high-resolution CT after surgery), were evaluated for special radiological features. Evaluation included, in 103 cases, anatomic parameters of the petrous bone and posterior fossa cavity and, in 202 cases, tumor-induced changes of bony structures, tumor relations with bony structures and with neural structures, and postoperative findings of bony structures and of neural tissues. These radiological parameters and the related clinical pre- and postoperative findings were transferred to a database for statistical evaluation of their positive or negative correlations, i.e., for their reliability in diagnosis and their importance in predicting postsurgical outcome. RESULTS: As important parameters, the following could be identified. The length of the posterior auditory canal wall and the interear difference of the maximum porus width both correlate with the degree of preoperative hearing deterioration (P < 0.05). The extent of the widening of the internal auditory canal is of predictive importance for the chances of postoperative hearing preservation or hearing loss (P < 0.01). The extent of tumor growth anterior and caudal to the internal auditory canal in large tumors is of significant importance for prediction of postoperative hearing function (P < 0.05). The tumor extension in all directions and the extent of cystic tumor components correlate with the pre- and postoperative function of the facial and cochlear nerves. The positions of the labyrinthine structures and their geographical relations to the fundus and the sigmoid sinus and, thereby, to the suboccipital route, enable reliable calculations of the danger of labyrinthine destruction and help improve the planning of the surgical strategy. DISCUSSION AND CONCLUSIONS: In addition to the importance for surgical planning, preoperative bone window CT and contrast-enhanced images offer the opportunity to identify traits of tumor biology, such as bony destruction of the internal auditory canal, tumor shape and cyst formation, and aspects with predictive importance for postoperative outcome. The average size for hearing preservation in tumors was 14.5 × 16.5 × 11.8 mm (coronal × sagittal× axial). The recent finding (8) of a higher presentation age in female patients has an apparently anatomic basis, which is a relatively larger internal auditory meatus.

Management of vestibular schwannomas (acoustic neuromas): radiological features in 202 cases--their value for diagnosis and their predictive importance.

Tumor-induced bony and soft tissue findings might reflect, in part, the biological characteristics of vestibular schwannomas and could predict clinical findings. In addition, the role of the individual anatomic conditions of the posterior fossa is of interest to the surgeon. Of 1000 vestibular schwannomas treated surgically at the neurosurgical department at Nordstadt Hospital, 202 cases, which were consecutively investigated at the same computed tomography (CT) unit and using the same technique (high-resolution CT at bone windows before and after surgery, contrast-enhanced high-resolution CT before surgery, and native high-resolution CT after surgery), were evaluated for special radiological features. Evaluation included, in 103 cases, anatomic parameters of the petrous bone and posterior fossa cavity and, in 202 cases, tumor-induced changes of bony structures, tumor relations with bony structures and with neural structures, and postoperative findings of bony structures and of neural tissues. These radiological parameters and the related clinical pre- and postoperative findings were transferred to a database for statistical evaluation of their positive or negative correlations, i.e., for their reliability in diagnosis and their importance in predicting postsurgical outcome. As important parameters, the following could be identified. The length of the posterior auditory canal wall and the interear difference of the maximum porus width both correlate with the degree of preoperative hearing deterioration (P < 0.05). The extent of the widening of the internal auditory canal is of predictive importance for the chances of postoperative hearing preservation or hearing loss (P < 0.01). The extent of tumor growth anterior and caudal to the internal auditory canal in large tumors is of significant importance for prediction of postoperative hearing function (P < 0.05). The tumor extension in all directions and the extent of cystic tumor components correlate with the pre- and postoperative function of the facial and cochlear nerves. The positions of the labyrinthine structures and their geographical relations to the fundus and the sigmoid sinus and, thereby, to the suboccipital route, enable reliable calculations of the danger of labyrinthine destruction and help improve the planning of the surgical strategy. In addition to the importance for surgical planning, preoperative bone window CT and contrast-enhanced images offer the opportunity to identify traits of tumor biology, such as bony destruction of the internal auditory canal, tumor shape and cyst formation, and aspects with predictive importance for postoperative outcome. The average size for hearing preservation in tumors was 14.5 x 16.5 x 11.8 mm (coronal x sagittal x axial). The recent finding (8) of a higher presentation age in female patients has an apparently anatomic basis, which is a relatively larger internal auditory meatus.

Reconstruction of the posterior auditory canal wall with a hydroxyapatite prosthesis.

Reconstruction of the posterior auditory canal wall with a prosthesis of porous hydroxyapatite ceramic is described. The implant material is the inorganic basis of the bone matrix and is remodelled into living bone tissue. Thirty patients in whom the cavity was restored with the technique described were followed for at least 2 years, with an average of 3 1/2 years. There was no extrusion. The use of a periosteal flap and replacement of the remnants of the epithelium of the tympanic membrane and former ear canal were essential for the formation of a good epithelial lining in the new ear canal. Sufficient eustachian tube function is essential for a lasting result, as demonstrated in one patient with a recurrent otitis media. A limited retraction of the new tympanic membrane was observed without recurrent cholesteatoma in two patients.

Bioactive glass‐ceramics in ear surgery: Animal studies and clinical results

In the search for better materials for middle ear reconstruction, ceramics have been suggested as an alternative. The bioactive glass-ceramic Ceravital was made available to us for animal experiments and clinical trials. To test its suitability in ear surgery, 101 ear operations were carried out in 53 rabbits including the reconstruction of 78 posterior auditory canal walls and the insertion of 174 middle ear implants. Parameters studied include the effects of bone paté in inducing new bone growth, the chronological course of bone apposition and remodeling, microscopic examination of mucous membrane growth on the implants and degree of lysis of the implant. In the past two and one half years some 250 ossicular prostheses have been implanted in man for reconstruction of the ossicular chain. A statistical analysis of 119 tympanoplasties after a follow-up of one and one half years shows no perforations of the tympanic membrane over the implants or rejection of the prosthesis from the middle ear. The audiological results achieved were more favorable with the use of ossicular prostheses made of bioactive glass-ceramic than those using allogenic ossicular grafts. On the basis of the histologic findings and observed clinical results, the bioactive material Ceravital is remarkably well suited for reconstruction of the posterior auditory canal wall and for implantation in direct contact with the tympanic membrane.

Facial paralysis and muscle-relaxant anesthesia.

THE FOLLOWING case report is presented primarily to forewarn otologists of the insidious danger of using succinylcholine-drip muscle-relaxant anesthesia in any surgical procedure where the identification of the seventh cranial nerve is important to its preservation. REPORT OF CASE A 32-year-old woman had chronic left mastoiditis of 10 years' duration. The history and findings follow: severe headache for one month, dizziness and nausea for two weeks associated with a positive fistula test. A radical mastoidectomy was performed on Nov. 7th, 1955. At operation, the mastoid bone was found to be eburnated. No cells were encountered; the posterior auditory canal wall and the adjoining mastoid area were taken down to the bridge simultaneously by means of gouges and mallet. As the bridge was being thinned down, what appeared to be a mastoid cell was uncovered 1 mm. below the horizontal semicircular canal and 1 mm. behind the crest of the facial

The Value of the Axial Projection of the Petrous Bone in the Diagnosis of Chronic Mastoiditis and Cholesteatoma

In chronic mastoiditis the pathological process is most frequently established within or near the mastoid antrum and tympanic cavity. In such cases, therefore, good roentgenographic demonstration of these structures is of paramount importance, but it is rarely if ever obtained by means of the routine projections. Law's and Schueller's lateral projections portray the extent and condition of the pneumatized area, the mastoid process, and the venous sinus. Stenvers' and Granger's projections allow visualization of the petrous apex, upper petrosal ridge, inner auditory meatus, and labyrinth. Taylor's base view demonstrates the petrous apex and inner auditory meatus from a different angle and shows their relation to the sphenoidal sinuses. None of these views, however, demonstrates the mastoid antrum. Recently, the cranially eccentric base views of Steward and Chamberlain-Towne have been recommended for problems concerning the mastoid antrum. In the author's experience, however, these do not display the wealth of detail and convincing clarity of the projection described some twenty-odd years ago by Ernst G. Mayer of Vienna. This view is technically difficult and intricate and the distortion of the temporal bone, with the exception of antrum, tympanic cavity, external auditory meatus and venous sinus, is considerable. Moreover, Mayer's instructions for placing the patient and arranging the tube and film cassette are difficult to follow. These difficulties probably explain why his projection has not become popular in the United States despite its undeniable merits. The purpose of this publication is merely to describe the positioning of the patient and the arrangement of tube and cassette more in detail, to give Mayer's useful projection another fair discussion, and further to add support by representative illustrations. The basic idea of Mayer's oddly distorted view of the mastoid area is to obtain a roentgenographic demonstration of the mastoid antrum, attic, tympanic cavity, and posterior auditory canal wall, particularly in conditions where sclerosis of the petrous bone has developed. In his projection the central ray strikes the temporal pyramid at an acute angle along its longitudinal axis (Fig. 1), resulting in a greatly distorted view of the petrous bone (Fig. 2). The antrum, attic, tympanic cavity, and posterior canal wall are, however, ideally visualized, undistorted, free from superimposed bone structures, presenting a surprising wealth of detail, “as if a curtain has been lifted from these structures.” Technic (Fig. 1a and b) A. Positioning the Patient and the Film Cassette (1) Assuming that the left mastoid is to be examined, place the patient in the supine position with the chin depressed sufficiently so that the base line of the skull—connecting the infraorbital ridge with the osseous external auditory meatus—assumes a vertical position.