Semiautomated Middle Ear Volume Measurement as a Predictor of Postsurgical Outcomes for Congenital Aural Atresia.

BACKGROUND AND PURPOSE: Middle ear space is one of the most important components of the Jahrsdoerfer grading system (J-score), which is used to determine surgical candidacy for congenital aural atresia. The purpose of this study was to introduce a semiautomated method for measuring middle ear volume and determine whether middle ear volume, either alone or in combination with the J-score, can be used to predict early postoperative audiometric outcomes. MATERIALS AND METHODS: A retrospective analysis was conducted of 18 patients who underwent an operation for unilateral congenital aural atresia at our institution. Using the Livewire Segmentation tool in the Carestream Vue PACS, we segmented middle ear volumes using a semiautomated method for all atretic and contralateral normal ears on preoperative high-resolution CT imaging. Postsurgical audiometric outcome data were then analyzed in the context of these middle ear volumes. RESULTS: Atretic middle ear volumes were significantly smaller than those in contralateral normal ears (P < .001). Patients with atretic middle ear volumes of >305 mm3 had significantly better postoperative pure tone average and speech reception thresholds than those with atretic ears below this threshold volume (P = .01 and P = .006, respectively). Atretic middle ear volume incorporated into the J-score offered the best association with normal postoperative hearing (speech reception threshold ≤ 30 dB; OR = 37.8, P = .01). CONCLUSIONS: Middle ear volume, calculated in a semiautomated fashion, is predictive of postsurgical audiometric outcomes, both independently and in combination with the conventional J-score.

The "boomerang" malleus-incus complex in congenital aural atresia.

"Boomerang" malleus-incus fusion deformity is identified on axial high-resolution CT in a subset of patients with congenital aural atresia, and it is associated with an absent incudostapedial joint and stapes capitulum and attachment of the incus to the tympanic segment of the facial nerve canal. Twelve patients with this deformity were identified on a retrospective review of imaging from a cohort of 673 patients with congenital aural atresia, with surgical confirmation in 9 of these patients. Eight of 9 patients underwent partial ossicular replacement prosthesis reconstruction with improvement in hearing outcome. We hypothesize that the boomerang anomaly represents a more severe ossicular anomaly than is normally seen in congenital aural atresia, arising from an arrest earlier in the embryonic development of the first and second branchial arch. This has potentially important implications for surgical planning because hearing outcomes with placement of prosthesis may not be as good as with conventional atresia surgery, in which reconstruction is performed with the patient's native ossicular chain.

An in vitro model system to study gene therapy in the human inner ear.

The confined fluid-filled labyrinth of the human inner ear presents an opportunity for introduction of gene therapy reagents designed to treat hearing and balance dysfunction. Here we present a novel model system derived from the sensory epithelia of human vestibular organs and show that the tissue can survive up to 5 days in vitro. We generated organotypic cultures from 26 human sensory epithelia excised at the time of labyrinthectomy for intractable Meniere's disease or vestibular schwannoma. We applied multiply deleted adenoviral vectors at titers between 10(5) and 10(8) viral particles/ml directly to the cultures for 4-24 h and examined the tissue 12-96 h post-transfection. We noted robust expression of the exogenous transgene, green fluorescent protein (GFP), in hair cells and supporting cells suggesting both were targets of adenoviral transfection. We also transfected cultures with a vector that carried the genes for GFP and KCNQ4, a potassium channel subunit that causes dominant-progressive hearing loss when mutated. We noted a positive correlation between GFP fluorescence and KCNQ4 immunolocalization. We conclude that our in vitro model system presents a novel and effective experimental paradigm for evaluation of gene therapy reagents designed to restore cellular function in patients who suffer from inner ear disorders.

Microvascular decompression of the vestibulocochlear nerve for disabling positional vertigo: the House Ear Clinic experience.

OBJECTIVE: To review characteristics of and outcome in patients undergoing microvascular decompression of the vestibulocochlear nerve. Patients studied had a diagnosis of disabling positional vertigo caused by a vascular loop compressing the VIIIth cranial nerve. STUDY DESIGN: Retrospective chart review and telephone interview. SETTING: Private practice tertiary neurotologic referral center. PATIENTS: Twenty patients with disabling positional vertigo underwent 25 retrosigmoid craniotomies for microvascular decompression between November 1990 and June 1999. The 4 men and 16 women ranged in age from 30 to 71 years (mean age, 46 yr). MAIN OUTCOME MEASURES: Charts were reviewed and patients were contacted by telephone and asked to rate severity of symptoms (tinnitus and dizziness) on a 4-point scale (none = 1, mild = 2, moderate = 3, and severe = 4) before and after surgery. They were also asked to rate their overall disability from their symptoms on the six-point scale established by the American Academy of Otolaryngology-Head and Neck Surgery. Preoperative and postoperative four-frequency (500 Hz, 1 kHz, 2 kHz, and 4 kHz) pure-tone average and speech discrimination scores were calculated and compared. Complications of surgery are also reported. RESULTS: Postoperative tinnitus score and dizziness score showed significant improvement from preoperative scores (p < or = 0.047 and p < or = 0.001, respectively), with 80% of patients improved in dizziness rating; 85% improved in their overall disability rating, and the difference from preoperative to postoperative was significant (p < or = 0.001). The mean postoperative pure-tone averages (15.4 dB) and speech discrimination scores (99%) did not differ from preoperative scores (11.9 dB and 98%). One patient lost all vestibular function in the operated ear (hearing remained intact) as the only complication of surgery. When asked, 83% of patients responded that they would have the surgery again. CONCLUSIONS: Diagnosing disabling positional vertigo secondary to vascular compression of the VIIIth cranial nerve remains the clinical challenge; a clear history plus air-contrast computed tomographic or magnetic resonance imaging make the diagnosis. Microvascular decompression of the vestibulocochlear nerve is a safe and effective operation for these carefully selected patients.

Hearing preservation in patients with vestibular schwannomas with sudden sensorineural hearing loss.

OBJECTIVE: We evaluated hearing outcomes in patients with sudden hearing loss and vestibular schwannoma who underwent a hearing preservation operation for tumor resection in an effort to determine whether a history of sudden sensorineural hearing loss has an impact on subsequent hearing preservation surgery. METHODS: Retrospective chart review of 45 patients operated between 1990 and 1998. Patients were divided into "Recovery" (n = 22) and "No Recovery" (n = 23) groups based on preoperative hearing recovery. Hearing preservation was assessed using the AAO-HNS hearing classification system. RESULTS: Measurable hearing was preserved in 73% of patients, with 47% having good postoperative hearing (AAO-HNS Classes A-B). There was no significant difference in hearing outcome from patients presenting with progressive hearing loss (45% Classes A-B). There was also no difference in postoperative hearing between the "Recovery" and "No Recovery" groups. CONCLUSIONS: Patients with sudden hearing loss and vestibular schwannoma have the same chance of hearing preservation after tumor removal as those with progressive loss. Preoperative recovery of hearing is not predictive of hearing preservation. Available data support the nerve compression theory as the mechanism of sudden hearing loss in patients with vestibular schwannoma.

Jacobson's nerve schwannoma: a rare middle ear mass.

The case of a 55-year-old woman with a middle ear mass is presented. The preoperative diagnostic workup, including an audiogram and imaging studies, and the histopathologic findings of the tumor are reviewed. The tumor, a schwannoma, arose from Jacobson's nerve in the middle ear. The surgical anatomy of Jacobson's nerve and the surgical approach to this tumor and to other tumors of the middle ear space are discussed. Tumors of the tympanic cavity are rare, with the exception of cholesteatoma; otherwise, the most common among them are paraganglioma and facial nerve neuroma. This report represents the first documented case of a schannoma arising from Jacobson's nerve in the tympanic cavity.

Plastic bottles as spacers for a pressurized metered-dose inhaler: in vitro characteristics

Homemade spacer devices are commonly used by children with asthma to improve aerosol deposition from pressurized metered dose inhalers (pMDI); however, the efficacy and efficiency of these devices are not fully characterized. We determined the quality of fine particle fraction (< 4.7 microns) and ultrafine particle fraction (< 3.3 microns) of three bottles (from 280 ml to 500 ml) commonly used as spacers in Trinidad and Tobago and compared their performance to the commercially available valved holding chamber (OpT) and pMDI. These data were obtained in vitro using a cascade impactor. All 3 bottles and the OpT were similar (p > 0.05) in reducing the amount of albuterol emitted as large particles (> 4.7 microns) to less than 10 micrograms. The different sized bottles (from 280 ml to 500 ml) produced identical quantities of albuterol in the fine particle and ultrafine particle ranges (p > 0.05). All of the sample bottle spacers emitted a higher amount (p < 0.002) of fine and ultrafine particles than the OpT and pMDI alone. The OpT resulted in a significantly higher fraction of fine particles (p < 0.05) and a greater quantity of drug (p < 0.05) in the ultrafine range as compared to the MDI only. The sizes of particles obtained from the bottle spacers are those that have a high probability of reaching the lower airway; however, the clinical relevance of these findings remains to be determined.

Plastic bottles as spacers for a pressurized metered-dose inhaler: In vitro characteristics

Homemade spacer devices are commonly used by children with asthma to improve aerosol deposition from pressurized metered dose inhalers (pMDI); however, the efficacy and efficiency of these devices are not fully characterized. We determined the quality of fine particle fraction (<4.7 um) and ultrafine particle fraction (<3.3 um) of three bottles (from 280 ml to 500 ml) commonly used as spacers in Trinidad and Tobago and compared their performance to the commercially available valved holding chamber (OpT) and pMDI. These data were obtained in vitro using a cascade impactor. All 3 bottles and OpT were similar (p>0.05) in reducing the amount of albuterol emitted as large particles (>4.7 um) to less than 10 ug. The diffreent sized bottles (from 280 ml to 500 ml) produced identical quantities of albuterol in the fine particle and ultrafine particle ranges (p>0.05). All of the sample bottle spacers emitted a higher amount (p<0.002) of fine and ultrafine particles than the OpT and pMDI alone. The OpT resulted in a significantly higher fraction of fine particles (p<0.05) and greater quantity of drug (<0.05) in the ultrafine range as compared to MDI only. The sizes of particles obtained from the bottle spacers are those that have a high probability of reaching the lower airway; however, the clinical relevance of these findings remains to be determined. (AU)

Plastic bottles as spacers for a pressurized metered-dose inhaler: in vitro characteristics.

Homemade spacer devices are commonly used by children with asthma to improve aerosol deposition from pressurized metered dose inhalers (pMDI); however, the efficacy and efficiency of these devices are not fully characterized. We determined the quality of fine particle fraction (< 4.7 microns) and ultrafine particle fraction (< 3.3 microns) of three bottles (from 280 ml to 500 ml) commonly used as spacers in Trinidad and Tobago and compared their performance to the commercially available valved holding chamber (OpT) and pMDI. These data were obtained in vitro using a cascade impactor. All 3 bottles and the OpT were similar (p > 0.05) in reducing the amount of albuterol emitted as large particles (> 4.7 microns) to less than 10 micrograms. The different sized bottles (from 280 ml to 500 ml) produced identical quantities of albuterol in the fine particle and ultrafine particle ranges (p > 0.05). All of the sample bottle spacers emitted a higher amount (p < 0.002) of fine and ultrafine particles than the OpT and pMDI alone. The OpT resulted in a significantly higher fraction of fine particles (p < 0.05) and a greater quantity of drug (p < 0.05) in the ultrafine range as compared to the MDI only. The sizes of particles obtained from the bottle spacers are those that have a high probability of reaching the lower airway; however, the clinical relevance of these findings remains to be determined.

Jacobson's nerve schwannoma presenting as middle ear mass.

Schwannoma is one of the common benign middle ear space tumors. Middle ear space schwannomas may originate from the nerves of the tympanic cavity or by extensions from outside the middle ear space. In the English-language literature, the facial nerve and chorda tympani nerve, but not yet the tympanic branch of glossopharyngeal nerve (Jacobson's nerve), have been reported as the origins of intrinsic middle ear space schwannomas. We present the clinical and radiologic features of a middle-space schwannoma originating from Jacobson's nerve, and suggest that such a tumor be included in the differential diagnosis of middle ear tumors.

Membranous tracheobronchial injury repaired with gastric serosal patch.

This unusual case involves pharyngolaryngoesophagectomy complicated by injury to the membranous trachea and right bronchus. Repair was possible after partial sternal split and elevation of the tracheostoma through the anterior mediastinum, pulling the stomach to the neck, and using the stomach as a patch to repair the injury to the membranous portion of the airway.

Time course of hearing loss in an animal model of pneumococcal meningitis.

A leading cause of morbidity from bacterial meningitis is an irreversible, usually profound sensorineural hearing loss, with an incidence as high as 30% in some studies. Bacterial meningitis remains the most common cause of acquired postnatal sensorineural deafness. Although several clinical studies have examined the long-term outcome of hearing in meningitis, few studies have examined the time course of hearing loss during the acute course of the disease. We have developed an animal model of meningogenic hearing loss in the rat and have plotted the time course of that hearing loss. Serial auditory brain stem responses (ABRs) were measured in rats inoculated in the cisterna magna (subarachnoid space) with Streptococcus pneumoniae (10(5) to 10(7) colony-forming units). All rats injected developed meningitis as evidenced by increased cerebrospinal fluid (CSF) white cell counts and positive CSF cultures. Serial ABR measurements taken 6, 12, 15, 18, 21, and 24 hours after inoculation demonstrated significant threshold shifts and eventual loss of the ABR waveform as compared with measurements in control rats injected with sterile culture medium. Hearing loss began approximately 12 to 15 hours after inoculation and progressed to complete loss by 24 hours (17 of 18 animals). No correlation was found between the magnitude of hearing loss and CSF white cell count or bacterial titer. Temporal bone histology of rats with meningitis shows a dense inflammatory cell infiltrate throughout the subarachnoid space. Labyrinthine inflammatory cells were confined to the scala tympani. The cochlear aqueduct is the proposed route of infection from the meninges to the labyrinth (scala tympani). Endolymphatic hydrops was also noted throughout the cochlea. These experiments both establish a reproducible animal model of meningogenic hearing loss and support the hypothesis that this hearing loss is progressive rather than abrupt in onset and is related to the duration of untreated infection. CSF inflammatory cells appear to enter the cochlea through the cochlear aqueduct. This reliable animal model will enable future studies directed toward further understanding the pathogenesis and pathophysiology of this hearing loss.

Magnetic resonance imaging in the early diagnosis of group A beta streptococcal necrotizing fasciitis: a case report.

Early diagnosis of invasive group A beta streptococcal (GABS) infection has been achieved in a patient using magnetic resonance imaging (MRI) complemented by needle aspiration. Life-saving treatments of GABS infection that include immediate surgical debridement along with the administration of i.v. antibiotics, gamma globulin, and hyperbaric oxygen were then implemented successfully to prevent the development of streptococcal toxic shock syndrome. While MRI is valuable in making early diagnosis of GABS, it should not delay surgical intervention.

A novel method for replacement of the dislodged tracheostomy tube: the nasogastric tube "guidewire" technique.

Unscheduled replacement of dislodged tracheostomy tubes can be a challenging procedure for the physician and a frightening event for the patient. Forceful attempts at replacement are both painful and dangerous; such attempts may disrupt the soft tissues adjacent to the tracheostomy tract, creating a false passage and potentiating acute respiratory failure. We describe a technique using a standard nasogastric tube that allows safe and precise replacement of tracheostomy tubes in both sedated and combative patients under routine and emergent conditions.

Issues on aural atresia for the facial plastic surgeon.

Rehabilitation of hearing in the child with congenital microtia and aural atresia is a fundamental part of the total reconstructive process. Not all children with microtia, however, are candidates for atresia repair. A grading scheme to evaluate a patient's candidacy for atresia surgery has been developed and facilitates the selection process. If aural atresia surgery is to be undertaken, the reconstructive surgeon planning microtia repair must be aware of certain concepts. We present our recommendations on the chronology and timing of surgeries, the relation of microtia repair to atresia repair, expectations after atresia repair, the importance of the conchal bowl and tragus, and the possibility of injuring an aberrant facial nerve. We stress close coordination of efforts between reconstructive surgeon and otologist to achieve the best possible functional and cosmetic outcome.