Biomedical subjects
R J Wiet
Publications and source records attributed to R J Wiet.
Update on conservative management of acoustic neuroma.
OBJECTIVE: To update the authors' experience with conservative management of acoustic neuromas. STUDY DESIGN: Retrospective chart review. SETTING: Private practice and tertiary care referral setting. INTERVENTION: Of 600 patients with acoustic neuroma, 102 were treated with the "wait and scan" treatment option. At least two magnetic resonance imaging scans were required of all patients. MAIN OUTCOME MEASURES: Change in tumor size over time was evaluated, as were clinical symptoms: hearing status, tinnitus, balance disturbance, aural fullness, vertigo, headache, and facial pain, numbness, or weakness. RESULTS: Of 102 patients, the average follow-up time interval was 28.5 months. Forty-five (44%) of 102 patients demonstrated a change in tumor size: an average total growth of 2.17 mm per year. In the remaining 54 patients (53%), no growth was demonstrated during a mean follow-up of 28.5 months. Three patients demonstrated actual tumor shrinkage. Of the 102 patients receiving conservative treatment, 85 (84%) reported hearing loss, 67 (66%) tinnitus, 37 (36%) balance disturbance, 29 (28%) aural fullness, 28 (27%) vertigo, 7 (7%) headache, 4 (4%) facial numbness, 2 (2%) facial weakness, and 0 (0%) facial pain. CONCLUSION: Conservative management-"wait and scan"-for selected patients with acoustic neuroma is a reasonable choice of management instead of radiation or microsurgery. In some situations the individual morbidities associated with surgery or radiation make those treatments not in the patient's best interests. A third option is necessary in patients who cannot or do not wish to undergo those other treatments.
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 surgeon's surgical experience. We also noted that as the patient's 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 surgeon's experience are the most significant factors influencing the facial nerve status and hearing outcome after removal of acoustic neuroma.
Facial nerve functions at hospital discharge after acoustic neuroma surgery.
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Normal audiologic presentations in patients with acoustic neuroma: An evaluation using strict audiologic parameters.
Although several studies have previously reported on patients presenting with "normal" audiologic parameters in acoustic neuroma, the present study is, to our knowledge, the first to exclusively examine in detail cases involving exceptionally stringent objective audiometric features. Of 369 patients with acoustic neuroma who were operated on between April 1980 and April 1997 by our group, 10 had strictly normal hearing, defined as follows: (1) pure-tone average < 20 dB; (2) speech discrimination score > 90%; and (3) interaural differences </= 10 dB at every hertz level. A high level of audiologic functioning was found to significantly lower the sensitivity of auditory brainstem response in the detection of acoustic neuroma. Magnetic resonance imaging was the only preoperative test exhibiting 100% sensitivity in this setting. Thus, a high level of clinical suspicion appears warranted in any case involving unexplained unilateral audiovestibular symptoms-including those instances in which strictly normal hearing parameters exist and are associated with negative auditory brainstem response findings.
Evaluation of three intraoperative auditory monitoring techniques in acoustic neuroma surgery.
OBJECTIVE: To assess the efficacy of three intraoperative auditory monitoring techniques: auditory brainstem response (ABR), electrocochleography (ECoG), and direct eight nerve monitoring (DENM). STUDY DESIGN: A retrospective review of the intraoperative recordings of ABR, ECoG, and DENM was performed. SETTING: A private, neurotologic practice. PATIENTS: Sixty-six patients with usable preoperative hearing underwent intraoperative auditory monitoring with ABR, ECoG, or DENM. INTERVENTIONS: Intraoperative auditory monitoring. MAIN OUTCOME MEASURES: Postoperative pure-tone hearing threshold and word recognition scores. RESULTS: Of the 66 patients, 16 (24%) had postoperative serviceable hearing. Five (18%) of the 28 with ABR monitoring, 3 (17%) of the 18 with ECoG monitoring, and 8 (40%) of the 20 with DENM monitoring had serviceable hearing after surgery. CONCLUSIONS: This study suggests that DENM may be more effective than ABR or ECoG, although the differences in hearing preservation rates are not statistically significant.
Stereotactic radiosurgery for acoustic neuromas: a survey of the American Neurotology Society.
OBJECTIVE: The purpose of this study was to better understand the complications, outcomes, and surgical difficulties in treating acoustic neuroma patients who have undergone stereotactic radiosurgery (SRS). STUDY DESIGN: A six-page, 28-item questionnaire was mailed to 395 members of the American Neurotology Society. SETTING: The study was conducted through an academic neurotologic practice. Questionnaire respondents were neurotologic physicians in private and academic practice. PATIENTS: A total of 46 patients who had undergone SRS were evaluated. INTERVENTIONS: Twelve (26%) of the 46 patients required microsurgery after SRS. MAIN OUTCOME MEASURES: Posttreatment cranial nerve status and the development of complications such as cerebrospinal fluid leak, meningitis, and cerebrovascular accident were evaluated. RESULTS: In the group of 12 patients who underwent microsurgery after SRS, 11 patients had some form of postoperative facial paralysis. Anacusis was present in all 12 patients. Two of the 12 patients had new-onset trigeminal neuropathy postoperatively. CONCLUSION: Microsurgical resection of acoustic neuroma after SRS is technically difficult. The difficulty exists regardless of the time of microsurgical resection after SRS. Patients who underwent microsurgery after SRS had uniformly poor cranial nerve results.
A technique to prevent cerebrospinal fluid leakage after translabyrinthine approach.
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Complications of the translabyrinthine approach for the removal of acoustic neuromas.
OBJECTIVE: To report the complications that occurred during a large series of surgical procedures for the removal of acoustic neuromas using the translabyrinthine approach. DESIGN: Retrospective analysis. SETTING: Neuro-otology practice with academic affiliation. Procedures were performed at either a university medical center or a community hospital in conjunction with a neurosurgery team. PATIENTS: A total of 258 patients (142 men, 116 women; mean age, 51 years) underwent the translabyrinthine approach during a 14-year period. All patients had a histologically proven diagnosis of acoustic neuroma. RESULTS: There were no deaths. There were 3 cases (1.1%) of neurovascular compromise. There were 20 cases (7.8%) of cerebrospinal fluid leak, 16 (80%) of which presented as rhinorrhea and 4 (20%) as incisional leaks. The leaks at the incision responded to conservative management, while rhinorrhea usually required more aggressive means of closure. Four patients (1.6%) were diagnosed as having bacterial meningitis. Complete gross tumor removal was not achieved in 4 patients (1.6%). Facial nerve function, as measured by the House-Brackmann system, was recorded in all patients at 1 year: 76% had a score of I or II; 18%, a score of III or IV; and 6%, a score of V or VI. Other complications included 3 cases of pneumonia, 1 case of severe gastric hemorrhage, and 1 case of wound infection. CONCLUSIONS: The results of this series generally agree with those of other large series and demonstrate the safety and effectiveness of the translabyrinthine approach in excising acoustic neuromas.
Pressure-induced ocular torsion.
We describe 3 patients within whom ocular torsion could be induced by application of positive air pressure to one external ear canal. In all cases, the superior pole of the eye rotated away from the stimulated ear when positive pressure was applied. The amplitude of torsion ranged from 3 degrees to 16 degrees. Exploratory tympanotomy was performed in all 3 patients. In 2 patients, round-window fistulas were found and repaired. In the third patient, no fistula was noted but the oval- and round-window areas were patched. There was no resolution of symptoms after surgery in any patient. Based on these cases, patients presenting with pressure-induced ocular torsion are unlikely to have resolution of their symptoms, even when a perilymphatic fistula is confirmed and repaired. We hypothesize that pressure-induced ocular torsion is caused by an irreversible juxtaposition of the utricle and stapes footplate.
Pitfalls in the diagnosis of hemifacial spasm.
Hemifacial spasm (HFS), a condition characterized by involuntary unilateral facial spasms, is a disabling disorder resulting in functional compromise, patient frustration, cosmetic deformity, and social embarrassment. Compression of the seventh nerve at the root entry zone via vascular loop is presently the most widely accepted causative theory. Although less common, there are other entities that can result in HFS. Basic evaluation, including a thorough history, physical examination, and magnetic resonance imaging (MRI) scan, is important to confirm the diagnosis and rule out other causes. The relation of vascular loop syndrome to HFS is well enough established that radiologic documentation of a vascular loop is probably not necessary in every case. Here we present 12 cases of HFS, 6 without VLS. The etiology and evaluation of HFS are reviewed.
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.
Rethinking the use of auditory brainstem response in acoustic neuroma screening.
The ability of magnetic resonance imaging (MRI) to detect very small acoustic tumors has triggered many to rethink the use of auditory brainstem response (ABR) in the screening of acoustic tumors. To assess ABR accuracy, we conducted a retrospective study of 388 surgically treated patients. Of these patients, 111 had complete databases including both preoperative MRIs and ABRs. The ABR was abnormal by wave V interaural latency difference in 106 (95%) of the cases. Although our overall sensitivity was 95%, sensitivity varied according to tumor size. ABR was abnormal or absent for all tumors (100%) larger than 2 cm in diameter, for 98% of tumors 1.1 to 2 cm in diameter, and for only 89% of tumors less than or equal to 1 cm in diameter. Ramifications of this in the decision-making process are presented. Criteria for cut-off values are also discussed.
A meta-analysis review of revision stapes surgery with argon laser: effectiveness and safety.
OBJECTIVE: To determine whether there is an advantage in safety and outcome efficacy with the use of argon laser in revision stapes surgery as compared with conventional instruments. DATA SOURCES: A search of the published English-language literature, 1970-1995, was conducted using the following key words: revision, surgery, stapes, laser, stapedotomy, and argon laser. STUDY SELECTION: The following inclusion criteria were used to select articles for the meta-analysis: revision cases only, a comprehensive review of intraoperative pathological findings that led to the failure, and accurate documentation by the author, confirmed by our statisticians using a modified chi 2 test. Eleven studies without the use of the laser (n = 1,147 patients) and four studies with the use of the laser (n = 170 patients) including our own patients (n = 23) were entered into the model. DATA EXTRACTION: The data had to meet strict audiometric criteria, including preoperative and postoperative audiogram pure tone average air-bone gap; postoperative audiograms had to include five classifications, and these audiograms had to be obtained a minimum of 6 months after revision surgery. DATA SYNTHESIS: A log-linear model was developed for this meta-analysis study, with each study analyzed individually and collectively. CONCLUSION: Revision stapes surgery using the laser demonstrated statistically significant (p = 0.002) advantage in both safety and efficacy over revision procedures using conventional instruments.
Complications of the gamma knife.
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Intraoperative auditory monitoring in acoustic neuroma surgery.
Intraoperative auditory monitoring is a useful adjunct that is currently evolving. Near-field monitoring techniques such as electrocochleography and direct eighth nerve compound action potential are being used more frequently. The use of these two techniques is compared in 26 patients undergoing hearing preservation acoustic neuroma resection. Overall, 9 (35%) of the 26 patients had their hearing preserved. Three (23%) of the 13 with electrocochleography monitoring and 6 (46%) of the 13 with direct compound action potential monitoring had hearing preserved after surgery. Although there was a suggestion of improved results with direct compound action potential monitoring, the results were not statistically different. It was noted that lack of electrical response at the completion of the procedure (regardless of monitoring technique) was correlated with poor postoperative hearing, whereas the presence of a waveform at termination in no way predicted satisfactory postoperative hearing. The two techniques and their advantages and disadvantages are discussed.
Pathologic conditions of the external ear and auditory canal.
Primary care physicians are influential in diagnosing and initiating treatment of most pathologic conditions in patients with a history of hearing loss, chronic ear infection, diabetes, immunosuppression, or otologic symptoms with excessive exposure to sunlight. Lesions of the external ear and the external auditory canal (external acoustic meatus) are significant and common. Patients with such a history should have a thorough basic examination, which can be done with simple tools. Symptoms of hearing loss, otalgia, otorrhea, tinnitus, aural fullness, vertigo, and facial weakness may warrant referral of the patient to an otolaryngologist. The crux of preventing worsening otologic sequelae is early detection and treatment.
The legal aspects of surgical facial nerve injury.
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