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Biomedical subjects

D E Brackmann

Publications and source records attributed to D E Brackmann.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Recent advances in neuro-otology.

Four advances in the field of neuro-otology are described: (1) auditory brain-stem response audiometry, (2) electroneuronography, (3) the cochlear implant, and (4) the infratemporal fossa approach to the skull base. Auditory brain-stem response audiometry is an accurate method for the early detection of hearing impairment and early diagnosis of acoustic neurinomas. Electroneuronography accurately assesses the degree of injury to the facial nerve, thereby improving management of facial nerve lesions. The cochlear implant restores the sensation of sound to totally deaf patients. The infratemporal fossa approach is used to treat extensive lesions of the skull base.

Audiometry↗
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Cholesteatoma surgery: residual and recurrent disease. A review of 1,024 cases.

This is an analysis of 1,024 primary cases of mastoid surgery for cholesteatoma operated upon during a ten-year period at the Otologic Medical Group, Inc. Our philosophy of management of the mastoid in these cases has been as follows: 1) avoid an open mastoid cavity when possible; 2) perform the operation in two stages if necessary; 3) reexplore the mastoid and middle ear for residual cholesteatoma when indicated. One-third of 380 revised cases had residual cholesteatoma, disease left by the surgeon. In 260 cases in which the surgeon felt it unlikely that there was residual disease he found it in 23%. In 4% this residual cholesteatoma was found in the mastoid. The incidence of residual cholesteatoma was higher in children and in planned, as opposed to unplanned, revisions. Residual cholesteatoma was detected in the middle ear more frequently than in the epitympanum, and in the epitympanum more frequently than the mastoid. Indications for, and timing of, the reexploration are discussed. Recurrent cholesteatoma refers to a retraction pocket and must be differentiated from residual cholesteatoma; the causes, prevention and treatment are different. Recurrent cholesteatoma was detected in 5%. The most common complication of the disease was a labyrinthine fistula (10%). Operative facial nerve damage occurred in one case. The most common postoperative complication was graft failure (3%). Intact canal wall tympanoplasty with mastoidectomy should be performed as a two-stage procedure in most cases when used in the treatment of aural cholesteatoma.

Adolescent↗
PubMedDate not supplied

Facial nerve repair in cerebellopontine angle surgery.

Facial nerve continuity was restored during cerebellopontine angle tumor removal in nine cases. The distal facial nerve was rerouted from the stylomastoid foramen into the cerebellopontine angle. Direct suture was accomplished in seven cases while two required interposition of a greater auricular nerve graft. There was excellent return of facial function in eight of the nine cases. Overall results are superior to nerve substitution techniques. The facial nerve should be inspected for continuity following tumor removal. If one is not certain the nerve is intact, the proximal facial stump should be identified at the brain stem and facial nerve continuity reestablished. A nerve substitution procedure should be resorted to a later time only when the proximal facial stump is not identifiable.

Adult↗
PubMedDate not supplied

Brain stem potentials evoked by electrical stimulation of the cochlea in human subjects.

Brain stem potentials were recorded from scalp electrode to biphasic square wave electrical stimulation of implanted electrodes in the cochlea of three patients. Reliable potentials could be recorded that appeared 1.5 to 2.0 msec prior to the customary acoustically-evoked brain stem potentials. The effects of variations in electrical stimulus parameters of rate and intensity were measured. Brain stem potentials can provide objective indices of the effectiveness of electrical stimulation of the cochlea in man.

Acoustic Stimulation↗
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Reconstruction of the audiogram using brain stem responses and high-pass noise masking.

Contributions to the brain stem electrical responses (BSER) presumably initiated from specific frequency regions of the cochlea with center frequencies similar to the major audiometric frequencies (0.5, 1, 2, 4, and 8 kHz) are derived by the application of a high-pass noise masking technique utilizing click stimuli. In normal hearing subjects, these derived narrow-band responses from the midfrequency regions (4, 2, and 1 kHz) can be recognized at click levels as low as 10 dB HL. For the frequency regions around 8 kHz and 0.5 kHz, these derived responses can be discerned at click levels of 30 dB HL and higher. When one uses the lowest click level at which these derived responses can be obtained from a given frequency region, the differences between a patient with a hearing loss and a normal hearing subject correlate well with the amount of hearing loss (air conduction) recorded by conventional pure tone audiometry. Use of the high-pass noise masking technique to reconstruct the audiogram may be of great potential value in assessing young children and other individuals who cannot or will not respond to conventional audiometry.

Adolescent↗
PubMedDate not supplied

Electrocochleography and auditory brainstem electric responses in patients with pontine angle tumors.

In 45 patients with surgically proven pontine angle tumors, compound action potential (AP) and summating potential (SP) were recorded with transtympanic electrocochleography (ECochG) together with brainstem electric responses (BSER). The aims were to quantify the mechanism by which tumors cause hearing loss and evaluate the diagnostic potentials of ECochG and BSER for detecting eighth nerve and brainstem tumors. Except for AP latency and narrow band AP waveform, response parameters recorded by ECochG are uncorrelated. Four uncorrelated parameters were abnormal in only 10% of the cases, three in 25%, two in 40%, and one in 90%. The BSER criterion was the latency delay between waves I and IV and resulted in about 90% detection, improving to 95% when used in combination with ther interaural wave V delay criterion. ECochG results provide evidence that, for hearing losses up to 60 dB HL, the origin is cochlear, resembling that caused by Meniere's disease. Evidence is presented that the increase in I-V delay in the BSERs is caused by differential action of the tumor upon low and high frequency fibers in the auditory nerve and that desynchronization of the firings of the nerve fibers is of more importance than an increase in neural conduction time. ECochG as the sole test for detection of pontine angle tumors appears to be of limited value. Brainstem response on its own has great merits; however, it should be emphasized that no wave I was detected in about 30% of the cases. The 95% detection score obtained with BSER depends on specifying the latency of wave I. For these cases, we substituted the latency of the AP recorded by ECochG.

Acoustic Stimulation↗
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Evaluation of the auditory system: an update.

The purpose of this paper is to describe the audiologic techniques currently used at the Otologic Medical Group, Inc. Auditory threshold in children is determined by a combination of behavioral and objective audiometric techniques. When behavioral techniques fail, auditory brainstem response audiometry combined with impedance audiometry gives a good estimate of hearing thresholds. Impedance audiometry is a valuable addition to the diagnosis of cochlear otosclerosis. This technique is also of benefit in the neurotologic evaluation. Auditory brainstem response audiometry is the most accurate method of detecting an acoustic tumor. We no longer use SISI, tone decay, or Bekesy tests. The newer audiometric studies have greatly improved our evaluation of the auditory system.

Acoustic Impedance Tests↗
PubMedDate not supplied

The supratubal recess in cholesteatoma surgery.

Acquired attic retraction cholesteatoma involving the anterior epitympanum is infrequently encountered and even less frequently discussed in the literature. The lack of cholesteatoma in this region is mostly due to a ridge of bone extending inferiorly from the tegmen tympani, just anterior to the cochleariform process. The term "cog" was coined and popularized to refer to this bony ridge. Erosion of the cog by cholesteatoma matrix allows extension of cholesteatoma into the supratubal recess. A number of vital structures including the facial nerve, cochlea, middle fossa dura, and internal carotid artery are intimately related to the supratubal recess. A clear three-dimensional understanding of these structures is necessary to remove disease safely from this area regardless of whether the posterior canal wall is left up or taken down. We present a series of dissection illustrations of the supratubal recess and discuss the possible routes of cholesteatoma extension. A series of patients with varying degrees of involvement of the supratubal recess and related structures is presented, and the pitfalls and management of cholesteatoma in this area are discussed.

Adolescent↗
PubMedDate not supplied

Porous polyethylene prosthesis: continuing experience.

Members of the Otologic Medical Group have been using a porous polyethylene prosthesis since mid-1976. Several modifications of technique have evolved, which are described. Short-term hearing results are the same as with previous techniques, but they are more stable long term. Extrusion now occurs in approximately 5% of cases, usually due to a eustachian tube problem. In general we are pleased with our results and plan to continue to use these prostheses.

Ear Ossicles↗
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Seventh nerve spasm: effect of modification of cholinergic balance.

The seventh cranial nerve spasms of the face and the eyelids, including essential blepharospasm, are usually intractable and sometimes disabling. Deanol acetamidobenzoate was compared with the anticholinergic orphenadrine for relief of these spasms. Deanol cured two of 16 (12%) subjects and improved a third. Orphenadrine was much more effective, improving the conditions of 16 of 26 (62%) subjects between 57% and 100%. A crossover double-blind experiment showed high significance over a placebo.

Adult↗
PubMedDate not supplied

Rare tumors of the cerebellopontine angle.

IN a series of 1,354 cerebellopontine angle tumors treated at the Otologic Medical Group, approximately 10% were lesions other than acoustic neurinomas. Of the non-acoustic tumors, the majority were meningiomas, primary cholesteatomas, and neurinomas of other cranial nerves in the posterior fossa. Twenty-five other lesions were encountered; these rare tumors are the subject of this study. The benign tumors resemble acoustic neurinomas in appearance and in the method of treatment. Malignant tumors are characterized by rapid development of symptoms and are difficult to treat because of invasion of vital structures in the area.

Arachnoid↗
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Arachnoid cysts of the posterior fossa.

The clinical symptoms and signs of four patients with arachnoid cysts in the posterior fossa are discussed. In three patients, the cyst was in the internal auditory canal; one patient had an acoustic neuroma and two large cysts in the cerebellum. Whereas the conventional diagnostic tests for acoustic neuroma cannot differentiate between neuromas and arachnoid cysts, the newer thin section body scanners can show a lesion with no enhancement in the case of the cyst. Surgical approaches for removal of this lesion must take into consideration the preservation of hearing in the involved ear.

Adult↗