Fibrous incudostapedial joint in congenital aural atresia.

OBJECTIVES: (1) Determine the prevalence of a non-bony or fibrous incudostapedial (IS) joint in the setting of congenital aural atresia. (2) Assess this anomaly's impact on surgical management and associated hearing outcomes. STUDY DESIGN: Retrospective chart review. SETTING: Subspecialty private practice. SUBJECTS AND METHODS: Operative reports and audiometric data of patients who underwent congenital aural atresia repair by a single surgeon from 2007 to 2011 were reviewed for operative anatomic findings and audiometric outcomes. RESULTS: Two hundred twenty-eight operations on 206 ears were performed. Median age was 5 years old. Fifty-five (26.7%) of these ears had a fibrous IS joint. The severity of this anomaly was graded as mild in 23 ears, moderate in 20 ears, and severe in 12 ears. Mean postoperative pure tone air conduction (PTA2) in the severely fibrous group was 51 compared to 46 in the moderate group (P = .03) and 41 in the mild group (P = .006). Patients with a fibrous IS joint who underwent successful ossicular chain reconstruction (OCR) had a mean postoperative PTA2 of 30, which was a significantly better outcome than in patients with moderately or severely fibrous IS joints who did not have OCR (P < .05). CONCLUSION: A fibrous IS joint was seen in 27% of patients undergoing repair of congenital aural atresia. The severity of this anomaly has important implications for postoperative hearing results. These findings suggest that ossicular chain reconstruction should be performed in moderately or severely fibrous cases.

HEAR MAPS a classification for congenital microtia/atresia based on the evaluation of 742 patients.

OBJECTIVE: Describe anatomical and radiological findings in 742 patients evaluated for congenital aural atresia and microtia by a multidisciplinary team. Develop a new classification method to enhance multidisciplinary communication regarding patients with congenital aural atresia and microtia. METHODS: Retrospective chart review with descriptive analysis of findings arising from the evaluation of patients with congenital atresia and microtia between January 2008 and January 2012 at a multidisciplinary tertiary referral center. RESULTS: We developed a classification method based on the acronym HEAR MAPS (Hearing, Ear [microtia], Atresia grade, Remnant earlobe, Mandible development, Asymmetry of soft tissue, Paralysis of the facial nerve and Syndromes). We used this method to evaluate 742 consecutive congenital atresia and microtia patients between 2008 and January of 2012. Grade 3 microtia was the most common external ear malformation (76%). Pre-operative Jahrsdoerfer scale was 9 (19%), 8 (39%), 7 (19%), and 6 or less (22%). Twenty three percent of patients had varying degrees of hypoplasia of the mandible. Less than 10% of patients had an identified associated syndrome. CONCLUSION: Patients with congenital aural atresia and microtia often require the intervention of audiology, otology, plastic surgery, craniofacial surgery and speech and language professionals to achieve optimal functional and esthetic reconstruction. Good communication between these disciplines is essential for coordination of care. We describe our use of a new classification method that efficiently describes the physical and radiologic findings in microtia/atresia patients to improve communication amongst care providers.

Anatomical facial nerve findings in 209 consecutive atresia cases.

OBJECTIVE: Describe intraoperative facial nerve findings in 209 consecutive atresia cases. Identify preoperative and intraoperative anatomical variants that should alert the surgeon to potential high-risk facial nerve anatomy. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care subspecialty private practice. METHODS: Retrospective review of 209 consecutive atresia cases treated between 2007 and 2011. Descriptive analysis of intraoperative findings. Logistical regression models with generalized estimating equations were used to examine the effect of preoperative variables over the operative findings. RESULTS: Two hundred and nine consecutive patients (ages 2-48) underwent atresia repair between 2007 and 2011. Preoperative Jahrsdoerfer Scale was 9 (23%), 8 (42%), 7 (19%), 6 (2%), 5 or less (2%). The facial nerve was found to have an abnormal course in 39% of the cases and not identified in 1%. It was congenitally dehiscent in 53% of cases and was surgically exposed in 10%. The most common site of congenital dehiscence was in the tympanic segment (57%). Facial-stapes contact was found in 11% of cases. The stapedius tendon was absent in 30% of cases. A single patient had a mild transient postoperative paresis (House-Brackmann 2). CONCLUSION: Atresia repair remains one of the most challenging procedures in otology. In spite of modern preoperative imaging, the facial nerve remains at risk. When performing surgery on patients with preoperative facial nerve paresis and/or lower Jahrsdoerfer scores, the surgeon should be aware of a higher incidence of facial nerve abnormalities. Thorough knowledge of anatomical variations and meticulous surgical technique are mandatory to safely perform these surgeries.

Scalp as split thickness skin graft donor site for congenital atresia repair.

OBJECTIVE: Describe the use of the scalp as a donor site for split thickness skin grafts in otologic surgery. MATERIALS AND METHODS: Review of the literature with detailed description of surgical technique and authors' experience. RESULTS: One hundred and forty- four scalp split thickness skin grafts were obtained between 2007 and 2011. No significant complications were observed with optimal cosmetic results. CONCLUSIONS: The scalp is a viable option as a split thickness skin graft donor site for otologic and other head and neck surgery. Advantages include improved cosmetic results at the donor site, quick healing with low complication rates, and easy accessibility in the operative field.

Rarely reported ocular complications following surgery to correct chronic suppurative otitis media.

The objective of this study was to describe the rarely reported ocular complications following surgery to correct chronic suppurative otitis media. A retrospective analysis was made of 2,318 cases of chronic suppurative otitis media treated with surgery between January 2004 and December 2009 at West China Hospital, Sichuan University, a medical center in Western China. Ninety-two cases of ocular complications were identified, giving an incidence of 3.97%. In 63 of the 92 cases (68.48%), the patients complained of blurred vision and the condition was classified as grade 1. In 24 cases (26.09%), the patients complained of mild periorbital edema and the condition was classified as grade 2. Four cases (4.35%) were classified as grade 3 because of severe edema with erythema on eyelids. One case (1.09%) was classified as grade 4 because of periorbital ecchymosis in addition to edema. The clinical features and the possible etiology were analyzed and are discussed. Ocular complications following chronic suppurative otitis media surgery are rare. Preauricular incision, disturbance of venous and lymphatic drainage, and preseptal cellulitis were the possible etiological factors. Eye injury during surgery and use of an anticholinergic agent might be risk factors for blurred vision after this surgery.

Current concepts in repair of aural atresia.

PURPOSE OF REVIEW: To look at the current rationale behind surgical candidacy for aural atresia. In addition, we review recent technical aspects of the procedure, as it relates to outcomes. RECENT FINDINGS: Traditionally, aural atresia repair has been mostly reserved for bilateral atresia patients or occasionally unilateral patients with ideal conditions. Repair has also typically followed microtia repair with cartilage reconstruction. Developing literature, however, shows that the critical period of central auditory development precedes the typical timing of repair, particularly after rib cartilage microtia reconstruction. Newer synthetic microtia repairs have allowed atresia repair prior to microtia repair to capture the developmental advantages of binaural hearing early in life. We also review recent data on the use of ossicular prostheses in atresia repair regarding audiologic outcomes and other techniques attributed to better outcomes. SUMMARY: Atresia repair remains one of the most challenging otologic procedures. As techniques improve and we understand the developing auditory system, surgical criteria may shift, with more patients becoming candidates at a younger age.

International consensus on Vibrant Soundbridge® implantation in children and adolescents.

OBJECTIVE: Active middle ear implants augment hearing in patients with sensorineural, conductive, and mixed hearing losses with great success. However, the application of active middle ear implants has been restricted to compromised ears in adults only. Recently, active middle ear implants have been successfully implanted in patients younger than 18 years of age with all types of hearing losses. The Vibrant Soundbridge (VSB) active middle ear implant has been implanted in more than 60 children and adolescents worldwide by the end of 2008. In October 2008, experts from the field with experience in this population met to discuss VSB implantation in patients below the age of 18. METHODS: A consensus meeting was organized including a presentation session of cases from worldwide centers and a discussion session in which implantation, precautions, and alternative means of hearing augmentation were discussed. At the end of the meeting, a consensus statement was written by the participating experts. The present consensus paper describes the outcomes and medical/surgical complications: the outcomes are favourable in terms of hearing thresholds, speech intelligibility in quiet and in noise, with a low incidence of intra- and postoperative complications. CONCLUSIONS: Taken together, the VSB offers another viable treatment for children and adolescents with compromised hearing. However, other treatment options should also be taken into consideration. The advantages and disadvantages of all possible treatment options should be weighed against each other in the light of each individual case to provide the best solution; counseling should include a.o. surgical issues and MRI compatibility.

Genotyping with a 198 mutation arrayed primer extension array for hereditary hearing loss: assessment of its diagnostic value for medical practice.

Molecular diagnostic testing of individuals with congenital sensorineural hearing loss typically begins with DNA sequencing of the GJB2 gene. If the cause of the hearing loss is not identified in GJB2, additional testing can be ordered. However, the step-wise analysis of several genes often results in a protracted diagnostic process. The more comprehensive Hereditary Hearing Loss Arrayed Primer Extension microarray enables analysis of 198 mutations across eight genes (GJB2, GJB6, GJB3, GJA1, SLC26A4, SLC26A5, MTRNR1 and MTTS1) in a single test. To evaluate the added diagnostic value of this microarray for our ethnically diverse patient population, we tested 144 individuals with congenital sensorineural hearing loss who were negative for biallelic GJB2 or GJB6 mutations. The array successfully detected all GJB2 changes previously identified in the study group, confirming excellent assay performance. Additional mutations were identified in the SLC26A4, SLC26A5 and MTRNR1 genes of 12/144 individuals (8.3%), four of whom (2.8%) had genotypes consistent with pathogenicity. These results suggest that the current format of this microarray falls short of adding diagnostic value beyond the customary testing of GJB2, perhaps reflecting the array's limitations on the number of mutations included for each gene, but more likely resulting from unknown genetic contributors to this phenotype. We conclude that mutations in other hearing loss associated genes should be incorporated in the array as knowledge of the etiology of hearing loss evolves. Such future modification of the flexible configuration of the Hereditary Hearing Loss Arrayed Primer Extension microarray would improve its impact as a diagnostic tool.

Atresia repair before microtia reconstruction: comparison of early with standard surgical timing.

OBJECTIVE: To compare short-term results of atresia repair when performed before versus after microtia reconstruction. STUDY DESIGN: Retrospective case review. SETTING: Tertiary otologic referral center. PATIENTS: Congenital aural atresia with or without microtia: 70 cases over 24 months. INTERVENTION: Atresia repair before Medpor microtia reconstruction (ARM) versus atresia repair after microtia reconstruction with autogenous rib (ARR) versus atresia reconstruction without microtia (AR). MAIN OUTCOME MEASURES: Surgical outcomes, short-term postoperative audiometric results (at least 4 months after surgery but within the first postoperative year), complications. RESULTS: Data from the 3 groups are as follows: ARM, 31 patients with median age 4.2 years (range, 2.5-9.3 yr); ARR, 28 patients with median age 12 years (range, 6.9-61); and AR, 11 patients with median age 5.9 years (range, 5.5-59 yr). Preoperative computed tomographic grading using the Jahrsdoerfer scale demonstrated an average score of 7.4 (range, 6-9) for the ARM group, 7.7 (range, 6-9) for the ARR group, and 8.5 (range, 8-9) for the AR group. For patients scoring 8 to 10 on the Jahrsdoerfer scale, postoperative pure-tone average 2 for each group were as follows: ARM, 28 dB hearing loss (HL); ARR, 32 dB HL; and AR, 29 dB HL. For patients scoring 7 or less, postoperative pure-tone average 2 were as follows: ARM, 42 dB HL; and ARR, 41 dB HL (AR, no patients). Surgical complications of infection and facial nerve injury were not seen in any group. Meatal stenosis was higher in the ARR group. One patient in the ARM group suffered a high-frequency sensorineural HL. No patient receiving Medpor microtia reconstruction suffered a complication due to the presence of the ear canal before microtia reconstruction. CONCLUSION: Early results of ARM compare favorably with results achieved with atresia repair after microtia reconstruction with autogenous rib cartilage and with atresia repair without microtia repair. Hearing outcome and complications in this study are also comparable with previously reported expert results. Because restoration of binaural hearing has been shown to be advantageous for auditory development and function, timing of atresia repair can be considered before microtia reconstruction on an individual case basis, provided preoperative computed tomographic evaluation shows an adequate chance of surgical success.

Catecholamine-secreting paragangliomas: recent progress in diagnosis and perioperative management.

Catecholamine-secreting paragangliomas (CSPs) present challenges for the managing team of surgeons and anesthesiologists. Without proper preoperative management and planning, the patient is at high risk for complications and significant morbidity. A review of the literature looking at all aspects of the care of patients with CSP was performed to provide a consensus on the comprehensive care of these difficult patients. A case study is also provided to illustrate the management algorithm. Specific recommendations are made with regards to preoperative workup, including serum and urine testing, tumor localization, angiography, and embolization. Preoperative and intraoperative management techniques by the surgical and anesthesiology teams are discussed, including pharmaceutical interventions and fluid management. Aspects of postoperative care are also discussed. Management of patients with CSP requires significant attention to detail by a multidisciplinary team of surgeons and anesthesiologists. By following the recommendations included within this article, the morbidity associated with removal of these tumors can be significantly reduced or eliminated.

Genetic analysis of presbycusis by arrayed primer extension.

Using the Hereditary Hearing Loss arrayed primer extension (APEX) array, which contains 198 mutations across 8 hearing loss-associated genes (GJB2, GJB6, GJB3, GJA1, SLC26A4, SLC26A5, 12S-rRNA, and tRNA Ser), we compared the frequency of sequence variants in 94 individuals with early presbycusis to 50 unaffected controls and aimed to identify possible genetic contributors. This cross-sectional study was performed at Stanford University with presbycusis samples from the California Ear Institute. The patients were between ages 20 and 65 yr, with adult-onset sensorineural hearing loss of unknown etiology, and carried a clinical diagnosis of early presbycusis. Exclusion criteria comprised known causes of hearing loss such as significant noise exposure, trauma, ototoxic medication, neoplasm, and congenital infection or syndrome, as well as congenital or pediatric onset. Sequence changes were identified in 11.7% and 10% of presbycusis and control alleles, respectively. Among the presbycusis group, these solely occurred within the GJB2 and SLC26A4 genes. Homozygous and compound heterozygous pathogenic mutations were exclusively seen in affected individuals. We were unable to detect a statistically significant difference between our control and affected populations regarding the frequency of sequence variants detected with the APEX array. Individuals who carry two mild mutations in the GJB2 gene possibly have an increased risk of developing early presbycusis.

N-Acetylcysteine as an adjunct for refractory ear infections.

OBJECTIVE: To analyze the efficacy of Ciprodex otic augmented with N-acetylcysteine (NAC) against difficult ear infections. SUBJECTS: Subjects were selected with at least 1 month of continuous otorrhea despite at least 3 distinct medical or surgical treatments. INTERVENTIONS: Subjects received Ciprodex otic augmented with 0.5 or 2% NAC using standard dosing schemes. MAIN OUTCOME MEASURES: Serial audiometry and cessation of otorrhea by both history and binocular microscopy. RESULTS: Seven subjects were included with an average of 18.4 months of continuous otorrhea despite aggressive therapy. Cessation of otorrhea was achieved in 6 of 7 subjects generally within 4 weeks of treatment. One of these 6 subjects remains on chronic suppressive therapy. The remaining subject failed because of persistent noncompliance. No subjects demonstrated ototoxicity via pretreatment and posttreatment audiometry. CONCLUSION: Ciprodex otic augmented with NAC seems to have considerable efficacy against otherwise refractory ear infections. This technique may prove to be a simple and powerful option for the treatment of difficult ear infections.

Ultraminiature encapsulated accelerometers as a fully implantable sensor for implantable hearing aids.

Experiments were conducted to evaluate a silicon accelerometer as an implantable sound sensor for implantable hearing aids. The main motivation of this study is to find an alternative sound sensor that is implantable inside the body, yet does not suffer from the signal attenuation from the body. The merit of the accelerometer sensor as a sound sensor will be that it will utilize the natural mechanical conduction in the middle ear as a source of the vibration. With this kind of implantable sound sensor, a totally implantable hearing aid is feasible. A piezoresistive silicon accelerometer that is completely encapsulated with a thin silicon film and long flexible flex-circuit electrical cables were used for this study. The sensor is attached on the middle ear ossicles and measures the vibration transmitted from the tympanic membrane due to the sound in the ear canal. In this study, the sensor is fully characterized on a human cadaveric temporal bone preparation.

Nucleus Freedom North American clinical trial.

OBJECTIVE: To evaluate hearing outcomes and effects of stimulation rate on performance with the Nucleus Freedom cochlear implant (Cochlear Americas, Denver, CO). STUDY DESIGN AND SETTING: Randomized, controlled, prospective, single-blind clinical study using single-subject repeated measures (A-B-A-B) design at 14 academic centers in the United States and Canada and comparison with outcomes of a prior device by the same manufacturer. PATIENTS: Seventy-one severely/profoundly hearing impaired adults. RESULTS: Seventy-one adult recipients were randomly programmed in two different sets of rate: ACE or higher rate ACE RE. Mean scores for Consonant Nucleus Consonant words is 57%, Hearing in Noise Test (HINT) sentences in quiet 78%, and HINT sentences in noise 64%. Sixty-seven percent of subjects preferred slower rates of stimulation, and performance did not improve with higher rates of stimulation using this device. CONCLUSIONS: Subjects performed well, and there was no advantage to higher stimulation rates with this device. SIGNIFICANCE: Higher stimulation rates do not necessarily result in improved performance.

Silicone allergy: A new cause for cochlear implant extrusion and its management.

OBJECTIVE: We introduce silicone allergy as a rare cause for cochlear implant extrusion and discuss its management. STUDY DESIGN: Retrospective case series and literature review. SETTING: Tertiary referral centers. PATIENTS: Primary eligibility criteria included patients who experienced a delayed extrusion of their cochlear implants with negative wound cultures and had a suspected or a test-proven allergy to silicone components of an implant. INTERVENTIONS: Silicone allergy testing, explantation of a cochlear implant containing allergenic silicone materials, reimplantation with a custom-made cochlear implant excluding an allergenic silicone component. OUTCOME MEASURES: Uneventful wound healing and extrusion-free long-term follow-up after the reimplantation with a custom-made cochlear implant excluding an allergenic silicone component. RESULTS: Three known cases of cochlear implant extrusion as a result of silicone allergy have been noted from 1991 through 2004 in three cochlear implant programs in the United States. All three devices extruded, resulting in explantation of the old device and reimplantation with a new custom-made device eliminating the allergenic silicone component. Wound cultures were negative in all cases. All three patients experienced a delayed extrusion of their devices. Two of these patients had a test-proven allergy to the implant's silicone components, whereas the third patient was presumed to have a hypersensitivity solely on the basis of a clinical presentation. CONCLUSION: We propose that silicone allergy is a rare cause of cochlear implant extrusion. Patients experiencing cochlear implant extrusion, particularly with a delayed onset and negative wound culture results, should be tested for silicone allergy.

Modifications of standard cochlear implantation techniques for children under 18 months of age.

Cochlear implantation is being performed in increasingly younger children. We present a retrospective cohort of 19 patients with 23 ears implanted under 18 months of age. The mean age at implantation was 11.9 months, with the youngest being 6.8 months. The facial recess was narrow in nine ears (39%), including all premature infants. An inferiorly located stapedius tendon was sectioned in seven ears (30%) to facilitate round window access. Countersinking of the receiver-stimulator required dural exposure in 22 ears (96%). The receiver-stimulator was secured with sutures in 15 ears (65%) and within a tight pocket in eight ears (35%). Tympanostomy tubes were placed in 10 ears (43%). Cochlear implantation in very young children frequently necessitates modified surgical techniques.

Cochleostomy site: implications for electrode placement and hearing preservation.

CONCLUSIONS: With recent increased interest in minimizing intracochlear trauma and preserving residual hearing during cochlear implantation, increased attention must be paid to the cochleostomy site. The results of this paper demonstrate that the cochleostomy must be made inferior, rather than anterior, to the round window to ensure scala tympani insertion and to decrease the likelihood of insertion-induced intracochlear damage during electrode insertion. OBJECTIVE: To describe the complex anatomy of the hook region of the cochlea, specifically in relation to the optimal placement of the cochleostomy for cochlear implant electrode insertion to potentially achieve hearing preservation. The authors believe that previous industry recommendations and described surgical techniques have resulted in cochleostomies being placed in anatomical positions that possibly result in electrode insertions that damage the basilar membrane and/or other cochlear structures. MATERIAL AND METHODS: The results of a number of temporal bone studies were reviewed with attention being paid to the anatomical relationship of the basilar membrane and spiral ligament to the round window membrane. For different cochleostomy sites the potential for damage to intracochlear structures, particularly the basilar membrane and organ of Corti, was assessed. RESULTS: The review of electrode insertion studies into human temporal bones, as well as a post-mortem anatomical study of implanted temporal bones, showed an increased risk of scala vestibuli insertions and insertion-induced damage to intracochlear structures when the cochleostomy was performed more anterior to the round window. These results were endorsed by studies detailing the anatomy of the hook region of the cochlea.

Malleus-to-footplate versus malleus-to-stapes-head ossicular reconstruction prostheses: temporal bone pressure gain measurements and clinical audiological data.

HYPOTHESIS: Several clinical reports suggest that if the stapes superstructure is intact, ossicular reconstruction should be made to the stapes head rather than the footplate to achieve a better hearing outcome. To test this hypothesis, we compared the in situ mechanical performance of hydroxylapatite (HA) malleus-to-stapes-head (MSH) ossicular reconstruction prosthesis (ORP) with malleus-to-footplate (MFP) ORP, both manufactured by Project HEAR. BACKGROUND: ORPs are commonly used to replace a missing or deficient incus. However, hearing outcomes are highly variable, depending on the ORP material, design, surgical technique, and ORP positioning. METHODS: Cochleo-vestibular pressure measurements in human cadaveric temporal bones for the HA MFP ORP have been reported by Puria et al. (2005). In the present study, the ear canal pressure Pe and cochleovestibular pressure Pv were measured in cadaveric temporal bones with intact incus, removed incus, and MSH ORP reconstruction. The relative loss in gain, Lmsh, is defined as the ratio of Pv with reconstructed MSH ORP to intact incus and compared with Lmfp. A retrospective clinical audit of the pre- and postoperative audiologic results of patients who had undergone ossiculoplasty with either MSH or MFP ORP was conducted for comparison. RESULTS: For the 0.5 to 3 kHz frequency range, Lmsh magnitude is 6.2 dB lower than the Lmfp magnitude (p = 0.05). The retrospective audit of audiologic results after ossiculoplasty with either MSH or MFP ORP revealed a similar difference in gain between the two ORP designs with air-bone gap differences of 7.6 dB (p = 0.04) and air conduction threshold differences of 8.0 dB (p = 0.13) for these patients. CONCLUSION: The MFP ORP showed better average pressure gain compared with the MSH ORP across the speech frequencies. Surgeons performing ossiculoplasty with designs similar to Project HEAR HA ORPs, where there is direct columella-like connection between the malleus and stapes, should consider using the MFP ORP design to achieve a better postoperative audiologic result, even when the stapes superstructure is intact.

Evaluation of botulinum toxin A in treatment of tinnitus.

OBJECTIVES: The purpose of this study was to evaluate the potential benefit of botulinum toxin A in treatment of tinnitus with a prospective, double-blinded study design. STUDY DESIGN: Double-blinded, prospective clinical study. METHODS: Thirty patients with tinnitus were randomly placed into 1 of 2 treatment arms. Patients either received botulinum toxin A (20 to 50 units) or saline injection at the first treatment, and the opposite treatment 4 months later. Prospective data including tinnitus matching test, tinnitus handicap inventory (THI), tinnitus rating scale (TRS), and patient questionnaires were obtained over a 4-month period after each injection. RESULTS: Twenty-six patients completed both injections and follow-up and were included in data analysis. After botulinum toxin A, subjective tinnitus changes included 7 patients improved, 3 worsened, and 16 unchanged. Following placebo, 2 patients were improved, 7 worsened, and 17 unchanged. Comparison of the treatment and placebo groups was statistically significant (P < 0.005) when including better, worse, and same effects. A significant decrease in THI scores between pretreatment and 4 month postbotulinum toxin A injection (P = 0.0422) was recorded. None of the other comparisons of pretreatment to 1 month, or pretreatment to 4 months were significantly different. CONCLUSIONS: This small study found improvement in THI scores and patient subjective results after botulinum toxin A injection compared with placebo, suggesting a possible benefit of botulinum toxin A in tinnitus management. Larger studies need to be completed to further evaluate potential benefits of botulinum toxin A in treatment of this difficult problem.

Malleus-to-footplate ossicular reconstruction prosthesis positioning: cochleovestibular pressure optimization.

AIMS: To determine 1) the best position for hydroxylapatite malleus-to-footplate (MFP), ossicular replacement prosthesis (ORP) in reconstructed ears, and 2) whether preserving the stapes superstructure (SS), when present, has acoustic advantages. BACKGROUND: Positioning of the MFP-ORP head beneath the neck of the malleus may produce maximal force, whereas positioning beneath the manubrium of the malleus may produce the greatest displacement. It is not clear which is the optimal placement position. In addition, we look at the effect of the SS on sound transmission to the inner ear in ossicular reconstruction. METHODS: The ear-canal air pressure and vestibular hydro-pressure were measured in human cadaver temporal bones with incus intact, removed, and replaced with the MFP-ORP; the ORP head was placed at three different positions on the malleus (head, mid-manubrium, and umbo) while keeping its base at the center of stapes footplate with intact or removed stapes SS. The vestibular pressure ratio between the ear with intact incus and MFP-ORP reconstructed ear is defined as Lmfp, the loss caused by the prosthesis in relation to the normal ossicular chain. RESULTS: The mean magnitude of Lmfp, averaged in the important speech frequency region of 0.5 to 3 kHz, is approximately 7.8 dB at the neck with stapes SS. In comparison, mean magnitude of Lmfp for mid-manubrium without stapes SS is 15 dB (p = 0.04), and with the stapes SS it is 16 dB (p = 0.05), whereas at the umbo without SS it is 15 dB (p = 0.03). In the 8 kHz region, the mean magnitude of Lmfp is approximately 1 dB with the stapes SS intact and approximately 8.5 dB when it was removed (p < 0.09). CONCLUSION: There are significant physiologic advantages to placing the hydroxylapatite MFP-ORP beneath the neck of the malleus and preserving the SS.