The American journal of otology最新文献

Hypothesis: Paired-point matching and surface matching are highly accurate when used on the lateral skull base with an optical computer-aided surgery system.

Background: Computer-aided surgery on the lateral skull base can be done with a pointer system or with the microscope. An optical pointer system that uses anatomic landmarks and surface points has been developed in Bern, Switzerland.

Methods: Axial computed tomography of a cadaver skull was performed. The images were processed on a computer workstation. An infrared camera was used. A reference base mounted on the head and a needle pointer, both equipped with light-emitting diodes, were used. Different anatomic landmarks were determined on the computer image of the skull and were compared with the actual anatomic markers taken on the bone or on the skin simulation material, and the target error was defined. In a second step, additional surface points on different regions of the skull were taken, and the inaccuracy from the target was redetermined.

Results: The authors found a mean average error in accuracy from the target with paired-point matching alone in the best series of 0.79 mm. Under skin simulation, they found a deterioration with paired-point matching alone but an improvement in accuracy with surface matching.

Conclusion: For this navigation system, it is recommended that the following five anatomic points be selected for matching of the lateral skull base: the tip of the mastoid, the mastoid foramen, the umbo, the frontozygomatic suture, and the anterior nasal spine. For additional accuracy in clinical situations, surface matching is recommended.

Objective: This article describes a series of patients with nasopharyngeal carcinoma involvement of the cerebellopontine angle and discusses the clinical significance of this entity.

Setting: Tertiary referral center.

Study design: Retrospective case study.

Patients: Patients who were diagnosed with nasopharyngeal carcinoma with clinical features of cerebellopontine involvement by tumor.

Interventions: Cerebellopontine involvement by tumor confirmed by computed tomography, magnetic resonance imaging, or both.

Results: Patients with this entity either had advanced disease or had been treated previously for advanced nasopharyngeal carcinoma. They had varied clinical features attributable to cerebellopontine involvement, such as sensorineural deafness, dizziness, facial palsy, and facial numbness.

Conclusions: Cerebellopontine angle involvement by nasopharyngeal carcinoma is a difficult entity, both from the diagnostic and therapeutic points of view. In high-risk patients, particularly in patients who were previously treated for advanced nasopharyngeal carcinoma, a high index of suspicion for nasopharyngeal carcinoma involvement of the cerebellopontine angle is warranted when they experience unexplained neurootologic symptoms such as sensorineural hearing loss, dizziness and facial palsy.

Objective: To discuss the embryology, classification, clinical experience with, and management of first branchial cleft anomalies.

Study design: Retrospective case review.

Setting: Tertiary referral center.

Patients: Patients with a first branchial cleft anomaly.

Intervention: Surgery or revision surgery.

Main outcome measures: Classifications according to Work, Olsen, Chilla; previous diagnostic and therapeutic pitfalls; outcome of intervention (including facial nerve function).

Results: Between 1984 and 1999, first branchial cleft anomalies were diagnosed in 18 patients. Surgical treatment was the treatment of choice. The authors' approach in Work type I and type 2 lesions is described, and surgical aspects of revision surgery are discussed. The importance of early establishment of the relationship of the anomaly to the facial nerve is stressed. In 8 patients, previous surgical attempts had been undertaken without establishment of the diagnosis first. After intervention, the outcome was favorable.

Conclusions: First branchial cleft anomalies occur sporadically in ordinary clinical practice. They may go unrecognized or may be mistaken for tumors or other inflammatory lesions of in the periauricular region. However, the distinct clinical features, which can be derived from embryologic development, usually lead to the correct diagnosis. This avoids both treatment delay and eventual failure.

Objective: The goal of this study was to assess the effectiveness of the conservative management in patients with acoustic neuroma (vestibular schwannoma).

Study design: This retrospective study was performed in a university hospital.

Patients: Patients were selected for this wait-and-see policy on the basis of age, general condition, audiometric results, tumor size, and patient preference. The study group included 97 patients, 87 of whom had at least two neuroradiologic examinations. The mean age of this population was 63 years (29 to 89 years). The mean length of follow-up of this population was 31 months. Eighty-seven of these patients had at least two radiologic examinations (magnetic resonance imaging or computed tomography). The mean interval between the initial and follow-up radiologic examinations was 15 months.

Main outcome measures: Tumor size was measured by use of two-dimensional data in all patients. The mean tumor size was 12 mm. The growth rate of the tumor was estimated by comparison of the results of the measurements from the initial and follow-up neuroradiologic examinations.

Results: Of the 97 patients studied, 6 patients required surgery and 6 required radiotherapy. Sixty patients (62%) were still being treated conservatively at the end of the study period. Three patients of 28 who were classified as candidates for hearing preservation surgery lost their candidacy during the observation period. The mean annual tumor growth rate was 1.52 mm/year. The tumor was stable in size in 36% of patients, regressed in 11% of patients, or grew in 53% of patients. The growth patterns of the acoustic neuroma fell into five categories: continuous growth in 15% of patients, negative growth in 5%, growth followed by negative growth in 40%, negative growth followed by growth in 20%, and no variation of tumor size in 20%.

Conclusion: Conservative management of acoustic neuromas carries difficulties: long-term follow-up of the patients and unpredictability of the tumor growth pattern. A reliable and reproducible radiologic method for evaluating tumor size is of great importance.

Objective: External canal cholesteatoma (ECC) may develop spontaneously or as a consequence of infection, trauma, or surgery. There is little information on the relative incidence of ECC according to cause. An analysis of cases was conducted to compare the clinical, surgical, and radiographic features of different types of ECC.

Study design: Retrospective case review.

Setting: Tertiary referral center.

Patients: All patients with cholesteatoma of the external auditory canal.

Intervention: Treatment was variable, ranging from local debridement and topical antibiotics to tympanomastoidectomy.

Main outcome measure: Assignment of cause is based on the combination of clinical history, physical examination, and radiographic appearance.

Results: A total of 39 patients were reviewed, 5 of them with bilateral lesions. The cause was iatrogenic in 15, spontaneous in 13, trauma in 6, congenital in 2, postinflammatory in 2, and postobstructive in 1. Surgery was performed in 25 cases. Successful results were obtained in most patients.

Conclusion: The cause of an ECC is determined on the basis of clinical features and radiographic appearance. The treatment plan is influenced by the cause of the ECC. Surgery is frequently necessary in congenital, posttraumatic, postobstructive, and iatrogenic ECC. Spontaneous lesions are usually controlled with office debridement.

Objective: To compare two methods for measuring the size and growth rate of extracanalicular vestibular schwannomas: the method recommended in 1995 by the American Academy of Otolaryngology--Head Neck Surgery (AAO-HNS) and the maximum cerebellopontine angle (CPA) tumor diameter, i.e., the method often used in radiologic reports.

Study design: Retrospective clinical study.

Setting: Tertiary referral center.

Patients: Fifty-four patients with a radiologic diagnosis of unilateral extracanalicular vestibular schwannoma whose tumors were managed conservatively for a mean duration of 39.8 months (range 12-194 months).

Intervention: The extracanalicular component was measured by use of high-resolution magnetic resonance imaging (2- to 3-mm axial slices) at 6- to 12-month intervals.

Main outcome measures: Tumor diameter was calculated by two methods. In the AAO-HNS method, the axial image with the largest extracanalicular tumor diameter was selected, and the maximum anteroposterior (A-P) and medial-lateral (M-L) tumor diameters were calculated. The A-P diameter was calculated parallel to the posterior surface of the petrous temporal bone, and the M-L diameter was calculated perpendicular to it. The size of the tumor was calculated as the square root of the product of these two diameters. In the maximum CPA method, the maximum CPA tumor diameter in any direction was also measured.

Results: There was no significant difference between the two methods for measuring the extracanalicular tumor size and growth rate, although the maximum CPA diameter method was consistently greater than the AAO-HNS method. There was a strong positive correlation between the two methods for assessing tumor size and growth. The A-P and M-L extracanalicular tumor diameters also showed a strong positive correlation, suggesting that the extracanalicular portion of vestibular schwannomas tends to enlarge equally in both these directions.

Conclusion: There is a strong positive correlation between these two methods for assessing both the tumor size and the growth rate of extracanalicular vestibular schwannomas. However, because vestibular schwannomas tend to grow in both the A-P and the M-L directions, this suggests that the AAO-HNS method is preferable.

Objective: To describe the clinical significance of tumor-associated hemorrhage in patients with acoustic neuromas.

Study design: Retrospective chart review.

Setting: University-based, tertiary care teaching hospital.

Patients: Three patients with acoustic neuromas who experienced symptomatic tumoral bleeding.

Interventions: Radiographic imaging, surgical removal of tumors, and pathologic analysis.

Main outcome measures: Patient histories, radiologic characteristics, surgical results, and pathologic findings.

Results: Tumoral hemorrhage can occur in patients with acoustic neuromas. These three cases and a review of the world literature suggest that tumor size may be the most important risk factor for tumor-related hemorrhage.

Conclusion: These findings have implications for those patients with acoustic neuromas who choose not to have surgical removal.

Objective: To show that congenitally deaf children who receive a cochlear implant between 10 and 15 years of age find it significantly more difficult to learn the new signal, and that a history of sound detection at high frequencies with hearing aids is predictive of better outcomes in these children.

Study design: A retrospective study using a within-subjects design.

Setting: Children's Cochlear Implant Centre, Sydney (CCIC), Royal Prince Alfred Hospital, and the New Children's Hospital in Westmead are tertiary referral centers.

Patients: Forty-five congenitally deaf patients were grouped according to their age (in years) at implantation into group 1 (aged 10-15), group 2 (aged <10), group 2a (aged 6-9), and group 2b (aged 3-5). Within each group, individuals with previous hearing between 2 and 4 kHz before receiving a cochlear implant were identified, and their mean results were compared with those in their respective age-matched groups.

Interventions: Surgical implantation, intensive weekly habilitation at the CCIC.

Main outcome measures: Speech perception, speech production, and language measures were compared. Questionnaires and telephone interviews were conducted.

Results: Group 2 (age <10 years) consistently outperformed group 1 (10-15 years) on all outcome measures, and most of them learned to converse without lipreading. In group 1, children with previous aided hearing at high frequencies displayed exceptional gains in speech perception and speech production, with reduced dependence on lipreading. Previous high-frequency hearing does not benefit group 2.

Conclusions: Implant recipients aged 10 to 15 years experience more difficulty than younger children during the initial periods of device use. A history of high-frequency hearing before implantation in these individuals correlates with more rapid improvement.