Richard J. Wiet

The mismatch negativity cortical evoked potential elicited by speech in cochlear-implant users

The mismatch negativity (MMN) event-related potential is a non-task related neurophysiologic index of auditory discrimination. The MMN was elicited in eight cochlear implant recipients by the synthesized speech stimulus pair /da/ and /ta/. The response was remarkably similar to the MMN measured in normal-hearing individuals to the same stimuli. The results suggest that the central auditory system can process certain aspects of speech consistently, independent of whether the stimuli are processed through a normal cochlea or mediated by a cochlear prosthesis. The MMN shows promise as a measure for the objective evaluation of cochlear-implant function, and for the study of central neurophysiological processes underlying speech perception.

Long-term results of the first 500 cases of acoustic neuroma surgery.

OBJECTIVE This retrospective study focuses on 2 outcome results after surgical intervention for acoustic neuroma: (1) facial nerve status, and (2) hearing preservation. STUDY DESIGN A total of 484 patients with an acoustic neuroma. RESULTS Postoperative facial nerve outcomes were significantly different (P < 0.001) according to the size of the tumors. Tumor size had even more influence on the immediate postoperative results. In addition, statistical significance (P < 0.05) was demonstrated in comparing facial nerve outcomes with the surgeons surgical experience. We also noted that as the patients age increases, the likelihood for facial dysfunction may increase for all postoperative intervals. The overall success rate of retaining useful hearing was 27% (26 of 95). Class A hearing was retained in 66% (10 of 15) of cases operated on through middle fossa approach in the last 5 years. CONCLUSION This study demonstrates that tumor size and surgeons experience are the most significant factors influencing the facial nerve status and hearing outcome after removal of acoustic neuroma.

Translabyrinthine approach for the management of large and giant vestibular schwannomas.

Background The removal of large vestibular schwannomas through the translabyrinthine approach is still controversial. Materials and Methods A retrospective review was performed of 81 patients (58 men and 23 women) with vestibular schwannomas 3 cm or greater, who underwent tumor removal via the translabyrinthine approach between 1985 and 2000. The mean tumor size was 3.7 ± 0.81 cm, and the mean age of the patients was 47 ± 16.1 years. The largest tumor was 6 cm. All surgical procedures were performed in collaboration with a neurosurgery team. Results Total tumor removal was accomplished in 77 cases (95.1%). The facial nerve was preserved anatomically in 69 (85.2%) of the patients. In 4 patients, divided nerves were repaired by primary anastomosis. Facial nerve function was assessed immediately after surgery and 1 year or more after discharge. Good function (House-Brackmann facial nerve Grade I or II) was present in 45% of patients and acceptable function (Grades I–IV) in 80% of patients 1 year after resection of the tumor. Cerebrospinal fluid leakage occurred in 12 patients (17%), meningitis developed in 3 patients (4%), and 1 patient experienced a stroke immediately after surgery. There were no deaths caused by surgery in this series. Conclusion The translabyrinthine approach offers an excellent anatomical view of the cerebellopontine angle and a direct approach to the tumor with functional preservation of the facial nerve. Total removal is accomplished in most cases, with minimum incidence of morbidity and no incidence of mortality.

Early results with titanium ossicular implants

Objective To report the efficacy of titanium middle ear prosthesis for ossicular reconstruction. Study Design Retrospective chart reviews were performed for 25 patients who had undergone titanium ossicular implants between January 1, 1999, and June 1, 20001. Setting Tertiary otology referral center. Patients All patients had a minimum of 6 months of postoperative follow-up and no evidence of recurrent otologic disease. Intervention All patients had undergone ossiculoplasty using titanium middle ear implants. Main Outcome Measures Comparisons of preoperative and postoperative pure tone averages were performed. Air-bone gap closures and implant extrusion rates were measured. Results Overall mean pure tone averages improved 22.2 dB with air-bone gap improvement at 20.9 dB. Fifty-six percent of patients achieved air-bone gap less than 20 dB postoperatively. The overall extrusion rate was 4%. However, with the placement of cartilage graft interposed between the prosthesis and the tympanic membrane, no extrusion was observed. Conclusion Titanium implants provide comparable hearing improvement compared with other materials. The extrusion rate seems quite low if cartilage interposition graft is inserted. Its ease of handling, biocompatible properties, and sound conducting properties improve its efficacy as an ossicular implant.

Hearing preservation after acoustic neuroma resection with tumor size used as a clinical prognosticator.

Three hundred sixty‐four patients referred to the Chicago Otology Group for acoustic tumor removal between 1981 and 1995 were reviewed in a retrospective fashion. Of this group, 60 patients were candidates for hearing preservation surgery and thus underwent one of two surgical approaches to remove the tumor and preserve hearing. Eighteen patients had tumor removal via the middle cranial fossa approach, and 42 patients had tumor removed via the retrosigmoid approach. Of the 42 patients who underwent retrosigmoid removal, 33% had hearing preserved overall. Of the 18 patients in the middle fossa group, 44% had hearing preserved overall. The average tumor size of patients with preserved hearing in the retrosigmoid group was 1.4 cm, and in the middle fossa group was 0.74 cm. Of significance was the fact that in both groups of patients with a tumor of 1.5 cm or less there was a 50% chance of hearing preservation. In the group of patients with tumors larger than 1.5 cm there was only a 16% chance of preserving hearing. We propose that these data can be used for better counseling of patients preoperatively as to the chances of hearing preservation and the type of approach appropriate for each case.

Conservative management of patients with small acoustic tumors

Of 432 patients referred for treatment of their cerebellopontine angle tumors, 53 with acoustic neuromas were managed initially without intervention but with adequate follow‐up. Mean presenting tumor size in this subgroup of patients was 0.98 cm (range, 0.2 to 3.0 cm), and average growth rate was 0.16 cm per year. Twenty‐one patients demonstrated tumor growth with a mean follow‐up interval of 1.9 years. Of these 21 patients, 14 underwent microsurgical excision, 4 received radiation, 2 continued to be observed and 1 was lost to follow‐up. The remaining 32 (60%) had no demonstrable growth with a mean follow‐up of 2.13 years. Of these patients, 29 continue to be followed and 3 were lost to follow‐up.

Suboccipital Retrosigmoid Approach for Removal of Vestibular Schwannomas: Facial Nerve Function and Hearing Preservation

IN THIS REPORT, we discuss the pertinent bony, arachnoid, and neurovascular anatomy of vestibular schwannomas that has an impact on the surgical technique for removal of these tumors, with the goal of facial nerve and hearing preservation. The surgical technique is described in detail starting with anesthesia, positioning, and neurophysiological monitoring and continuing with the exposure, technical nuances of tumor removal, hemostasis, and closure. Positive prognostic factors for hearing preservation are also highlighted.

Inverted Papilloma of the Middle Ear and Mastoid

From the Departments of Otolaryngology-Head and Neck Surgery (Drs. Stone, Berktold, and Wiet) and Pathology (Dr. Ranganathan), Northwestern University Medical School. Presented at the Annual Meeting of the American Academy of Otolaryngology-Head and Neck Surgery, San Antonio, Texas, Sept. 14-18, 1986. Submitted for publication May 30, 1986; revision received Aug. 26, 1986; accepted June 8, 1987. Reprint requests: Robert E. Berktold, MD, Department of Otolaryngology-Head andNeckSurgery, Northwestern University Medical School, 303 East Chicago Ave., Chicago, IL 60611. His medical history revealed heavy drinking and cigarette smoking. A medial maxillectomy was performed I \12 years before his admission for treatment of an inverted papilloma of the right lateral nasal wall and maxillary sinus. At that time, an aural polyp extruded via a perforated tympanic membrane of the right ear. An excisional biopsy revealed squamous papilloma. Six months later, a modified radical mastoidectomy was performed. During surgery, the middle ear was noted to have extensive polypoid and granulation tissue, which was found to be epithelial papilloma with focal atypia. Because of recurrence, several more excisional biopsies of this middle ear and mastoid papilloma were performed. Specimens revealed squamous papilloma with focal moderate dysplasia. The patient was referred for further treatment. Evaluation at this time revealed a large friable, pink mass in the right ear canal. A well-healed maxillectomy cavity with no evidence of tumor was noted. The nasopharyngeal exam was unremarkable. Audiologic evaluation confirmed a moderately severe right-sided mixed hearing loss with a 63 dB pure-tone average. Computerized tomography demonstrated a mastoidectomy cavity in the right temporal bone with an associated bony destructive process (Fig. I). The patient was operated on February 27, 1986. Extensive

Superselective embolization of glomus jugulare tumors.

The purpose of this report is to introduce the technique of superselective embolization (SSE) and to review our experience in surgically treating glomus jugulare tumors with and without preoperative SSE. Retrospective chart review was performed to determine estimated blood loss and operative time, and illustrative case reports are presented. The technique of preoperative SSE represents an important advance in the surgical management of glomus jugulare tumors. In our experience, surgical ligation of tumor-feeding vessels or nonselective embolization of the external carotid system is unsatisfactory. Inadequate devascularization and excessive risk of complications have caused us and others to abandon these procedures. However, SSE performed by an experienced neuroradiologist can produce effective and safer tumor devascularization. Preoperative SSE results in shrinkage of tumor size and significantly decreases blood loss. The advantages to the surgeon include improved visualization and ease of dissection as well as increased confidence that complete tumor excision has been achieved.

Trends in the diagnosis and the management of Meniere's disease : Results of a survey

OBJECTIVE: To determine the practices of the American Neurotology Society (ANS) membership in the evaluation and treatment of the Menieres patient. STUDY DESIGN: Prospective. INTERVENTION: Questionnaire. MAIN OUTCOME MEASURE: Respondents’ response to questions pertaining to the diagnostic and therapeutic practices in the management of Menieres disease. RESULTS: Three hundred members of ANS were mailed a 15-item questionnaire. Two hundred three responded, for a 67.7% response rate. For the diagnosis of Menieres disease, 1 in 3 practitioners relied solely on history, physical exam, and audiometry, whereas 2 in 3 relied in part on adjunctive tests, such as electrocochleography (ECOG) and electronystagmography (ENG). Two in 3 practitioners pursued retrocochlear studies on initial evaluation, with the overwhelming majority using MRI. In treating Menieres disease, conservative medical management was preferred. For medically recalcitrant Menieres disease, endolymphatic sac surgery (ESS) was the most commonly employed initial intervention (50%), followed by transtympanic gentamicin (38%). Currently, <10% routinely recommend the Meniett device. Eighty-three percent include ESS as a therapeutic option for medically recalcitrant Menieres disease. The vast majority continue to perform surgical labyrinthectomies and vestibular nerve sections for Menieres disease. CONCLUSIONS: Menieres disease continues to pose a difficult diagnostic and therapeutic problem, resulting in heterogeneous approaches to both evaluation and treatment. Despite the 1995 American Academy of Otolaryngology guidelines in the diagnosis of Menieres disease, most clinicians rely in part on ENG or ECOG in diagnosing Menieres disease. Furthermore, despite the passing of 20 years since the publications claiming a purely placebo effect, ESS is the most commonly employed initial surgical treatment for Menieres disease. (Otolaryngol Head Neck Surg 2005;132: 722-6.)