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Biomedical subjects

P R Lambert

Publications and source records attributed to P R Lambert.

At least 19 recordsLinked to original sources
PubMed1998

Intact canal wall mastoidectomy with tympanoplasty for cholesteatoma in children.

OBJECTIVE/HYPOTHESIS: Cases of cholesteatoma in pediatric patients were reviewed to determine which factors influence the outcome of surgical treatment. Cholesteatoma is considered a more aggressive disease in children than in adults. The outcomes of intact canal wall (ICW) mastoidectomy and canal wall down (CWD) mastoidectomy were assessed, as comparisons of different surgical technique. STUDY DESIGN: A retrospective analysis of all cases of pediatric cholesteatoma treated at a single institution by the senior author (P.R.L.) over a period of 11 years was conducted. METHODS: Patient information was collected from an otology database, patient records, and audiology files. RESULTS: Sixty-six patients, aged 10 months to 18 years, were treated and followed for an average of 37.7 months (range 12.2 months to 12.5 y). ICW mastoidectomy with tympanoplasty was the primary surgical treatment in 41 patients. Nineteen percent had residual disease at a planned second stage surgery and 22% developed recurrent cholesteatoma for a total recidivism rate of 41%. A SRT of less than 30 dB HL was achieved in 75% of these patients. Seventeen patients underwent CWD mastoidectomy with tympanoplasty initially. Two patients (12%) had residual cholesteatoma found at a planned second state procedure, and no recurrent cholesteatoma was encountered. Seventy-two percent maintained a SRT of less than 30 dB HL. CONCLUSIONS: These results support the continued use of ICW mastoidectomy with tympanoplasty for pediatric cholesteatoma. If planned second stage surgery is necessary, the long-term results of an ear with useful hearing and few problems with chronic medical care are gratifying. For reasons of anatomy or in an only hearing ear, CWD mastoidectomy with tympanoplasty provides a safe ear and good hearing results. Mastoid cavity care must be maintained indefinitely in many cases.

Adolescent↗
PubMed1998

Congenital aural atresia: stability of surgical results.

OBJECTIVES/HYPOTHESIS: To compare early (<1 y) and longer-term (1.0-7.5 y; mean follow-up, 2.8 y) hearing results following surgery for congenital aural atresia and to analyze revision cases for cause of failure, time of occurrence, and outcome. STUDY DESIGN: Retrospective study of 55 consecutive patients (59 ears) undergoing surgery during an 11-year period for congenital aural atresia. METHODS: The best speech reception threshold (SRT) during the first postoperative year was compared with the most recent SRT beyond the first postoperative year. The complication rate and long-term hearing results (>1 y) for initial and revision surgeries were compared. RESULTS: In the early postoperative period, an SRT of < or =25 dB was achieved in 60% and an SRT of < or =30 dB in 70%. With longer follow-up (mean, 2.8 y), 46% of patients maintained an SRT < or =25 dB. Revision surgery was necessary in approximately one third of patients. Longer-term hearing results following initial surgery only or after revision surgery showed an SRT < or =25 dB in 53% and an SRT < or =30 dB in 64%. For primary and revisions surgeries the incidence of temporary facial paralysis was 1.5% and for significant hearing loss, 3.0%. CONCLUSIONS: Some degradation in hearing does occur as patients are followed beyond the first postoperative year. Revision surgery will be necessary in approximately one third of cases. With revisions, an SRT < or =25 dB can be expected in half of cases and an SRT < or =30 dB in two thirds of cases. The ability to provide these hearing results supports this surgery in unilateral cases.

Adolescent↗
PubMed1998

Facial nerve injury in congenital aural atresia surgery.

OBJECTIVE: This study aimed to determine those patients who have sustained a facial nerve injury during surgery for congenital aural atresia and pinpoint the site of injury vis-a-vis the operative approach. STUDY DESIGN: The study design was a retrospective review of >1,000 patients undergoing atresia repair. SETTING: The study was performed at a tertiary referral center. PATIENTS: The study consists of 10 patients with a facial nerve injury from atresia surgery. INTERVENTION: In 1 of 10 patients, the facial nerve was transected. This occurred during the skin incision at the level of the helix. A sural nerve cable graft was used to repair the severed nerve. MAIN OUTCOME MEASURES: High-resolution computed tomography of the temporal bone was the most important preoperative study. However, in cases of aural stenosis with cholesteatoma, the course of the facial nerve may be camouflaged. RESULTS: Ten of >1,000 patients operated on sustained a facial nerve injury from atresia surgery. Seven of these patients were those of the authors, whereas three had the initial surgery elsewhere, each by a different surgeon. CONCLUSIONS: For the inexperienced surgeon, the facial nerve is at its greatest risk in the inferoposterior portion of atretic bone just lateral to the middle ear. For the experienced surgeon, the facial nerve is at its greatest risk in those patients with low-set ears, canal stenosis, and an accompanying cholesteatoma.

Adolescent↗
PubMed1997

Cranial fasciitis presenting as an external auditory canal mass.

Cranial fasciitis is a rare benign lesion that develops in childhood. It is considered a subset of nodular fasciitis but occurs selectively in the scalp of children. A review of the world literature revealed only 22 other published cases and no previous reports of a lesion involving the petrous portion of the temporal bone or presenting as a mass in the external auditory canal. We report a rare case of cranial fasciitis in the petrous portion of the temporal bone of a neonate and present a review of the literature.

Biopsy↗
PubMed1997

Electrical middle ear muscle reflex: use in cochlear implant programming.

Programming of multichannel cochlear implants (CIs) requires subjective responses to a series of sophisticated psychophysical percepts. It is often difficult for young prelinguistically deaf children to provide adequate responses for device fitting. This is especially true in setting levels of maximum comfortable loudness, whereby failure to indicate growth of loudness may result in elevation of stimulus levels to the threshold of pain. The acoustic or stapedial muscle reflex has been used previously to provide objective confirmation of acoustic stimulation, and there have been attempts to use the reflex in hearing aid fitting. It has also been suggested that electrically elicited middle ear muscle reflexes (eMEMR) may have applicability in confirming and quantifying electrical stimulation through a CI. To assess the relationship between eMEMR characteristics and levels of loudness perception with CIs, determine reliability of the response, and investigate potential use of eMEMR in CI programming, 25 postlinguistically deafened adult CI users were evaluated. Reflexes have also been attempted on 40 children, with responses present in 31 (71%). Comfort levels predicted by eMEMR were highly correlated with those obtained through subjective judgments in the adult subjects. The eMEMR provides an objective, accurate, and rapid method of estimating maximum comfortable loudness levels, which may be useful in the initial programming of young implant recipients.

Acoustic Stimulation↗
PubMed1997

Analysis of small hair bundles in the utricles of mature guinea pigs.

HYPOTHESIS: This study aimed to determine whether hair cells with immature hair bundles exist in the normal utricular maculae of mature guinea pigs. BACKGROUND: A low rate of hair cell "turnover" occurs in the vestibular organs of normal adult birds. Small immature-appearing hair cells have been identified in the utricles of juvenile guinea pigs, but their existence in the vestibular system of mature mammals has not been confirmed. METHODS: Nine utricles from 14- to 16-week-old guinea pigs were processed for scanning electron microscopy. A systematic search for small hair bundles was made. These bundles were classified as either "newborn-like" or "intermediate" depending on specific characteristics of the apical cell surface, the stereocilia, and the kinocilium. RESULTS: A mean of 7 newborn-like and 41 intermediate hair bundles per utricle were identified. The average hair cell count for the guinea pig utricular macula was 7,200; thus, these small hair bundles comprise 0.7% of the total. CONCLUSIONS: The small hair bundles are interpreted as developing vestibular hair cells, produced to replace hair cells lost to normal processes. This is thought to represent a biologic phenomenon that is in some ways similar, but in other ways distinct, from hair cell regeneration after trauma.

Animals↗
PubMed1997

Evaluation of the dizzy patient.

This discussion has focused primarily on the history and physical examination of the patient with dizziness which, in fact, are the two most important elements in the evaluation process. To perform the examination expeditiously and completely, a broad differential diagnosis of dizziness must be kept in mind. The clinician should also keep in mind two basic objectives: first, to identify serious pathology (e.g., central nervous system lesion, brainstem ischemia, cardiac arrhythmia); and second, to recognize diseases that can be specifically treated, such as an endocrine abnormality, middle ear infection, Meniere's disease, or a drug reaction. Reassurance and/or vestibular rehabilitation are the mainstays of therapy for the patients not falling into the above two categories.

Dizziness↗
PubMed1996

Stapedectomy in residency training.

Because fewer stapedectomies are performed today, concern has focused on whether or not residents are adequately trained in stapedectomy techniques. A retrospective study was done of patients undergoing stapedectomy over the last 11 years. This series represents primary resident-assisted cases performed under direct supervision of the attending surgeon. For 102 consecutive stapedectomies, the air-bone gap was closed to within 10 dB in 91 (89%), and no serious complications occurred. These results are compared with other published results, and our philosophy of teaching stapedectomy in residency is discussed.

Follow-Up Studies↗
PubMed1996

Congenital malformations of the external auditory canal.

Abnormal development of the first and second branchial arches and the intervening branchial cleft and pharyngeal pouch can result in a variety of deformities affecting the external auditory canal and the middle ear. This article reviews several of these deformities, including external auditory canal stenosis and atresia (minor and major congenital ear malformations) and external auditory canal duplication anomalies (type I and type II branchial cleft cysts).

Bone Conduction↗
PubMed1995

Recovery of noise-induced changes in the dark cells of the quail tegmentum vasculosum.

Morphologic changes in the tegmentum vasculosum (TV) of adult quail after high intensity sound exposure were studied. Quail were continuously exposed to 115 dB SPL, 1500 Hz pure tone in a sound field for 12 h and either sacrificed immediately (0 day), 1, 2, 3, 4, 6 or 10 days later. Serial sections through the basilar papilla at 100 micron intervals from base to apex were obtained for study with light microscopy and TEM. Significant morphologic changes were found within the TV of quail sacrificed on days 0-4. On a quantitative scale, the majority of recovery occurred within the first 24 h. After four days survival the tegmentum appeared nearly normal. This recovery correlates well with the temporal pattern of threshold shift recovery. These results demonstrate a temporal correlation between ultrastructural changes in the TV and functional recovery of hearing after intense sound exposure. A potential etiologic role of the TV in avian temporary threshold shift is suggested.

Acoustic Stimulation↗
PubMed1995

The round window electromagnetic implantable hearing aid approach.

The round window electromagnetic implantable hearing aid (RWEM) approach uses a magnet surgically implanted onto the round window membrane of the cochlea to impart vibrational energy to the inner ear when driven by a nearby electromagnetic coil. In this article, experimental methods used in animal ABR studies are described for this approach and evidence for the viability of this technique is demonstrated by the similarity of ABR waveforms obtained using RWEM and acoustically-evoked stimuli.

Animals↗
PubMed1995

Sinus tympani: anatomic considerations, computed tomography, and a discussion of the retrofacial approach for removal of disease.

Surgical access to the sinus tympani remains a challenge for otologic surgeons. Usually, the retrotympanum is approached through the middle ear in an anterior to posterior direction during chronic ear surgery. Whether this is via a posterior tympanotomy or after canal wall down tympanomastoidectomy, visualization of the most posterior recess of the sinus tympani is often inadequate. The purpose of this investigation is two fold: (1) to describe the highly variable anatomy of the posterior tympanic cavity and (2) to review the retrofacial approach to the sinus tympani. Histologic sections, cadaver dissections, and diagrammatic illustrations are combined with computed tomographic (CT) imaging to provide a three-dimensional understanding of the sinus tympani and adjacent labyrinthine structures. Viewed from the mastoid, the anatomic structures that define the boundaries of the retrofacial approach include the facial nerve and stapedius muscle laterally, the lateral semicircular canal superiorly, the posterior semicircular canal posteromedially, the vestibule anteromedially, and the jugular bulb inferiorly. When the sinus tympani is well developed, saucerization within these boundaries gives wide access into the sinus and round window niche. The authors suggest that preoperative imaging can select patients who are candidates for a retrofacial approach to expose and remove disease in the sinus tympani. Contraindications to this approach include axial CT image measurements showing a contracted space between the posterior semicircular canal and the medial aspect of the facial nerve, lack of posterior expansion of the sinus tympani, and in cases where these measurements are marginal, the presence of a high jugular bulb or anteriorly positioned sigmoid sinus.

Ear Diseases↗
PubMed1995

Application of split-thickness skin grafts for acquired diseases of the external auditory canal.

Over the past 10 years a variety of acquired external auditory canal pathologies have been treated at the University of Virginia. Surgical intervention has been required in 16 patients (18 ears). The most common diagnosis in this group was canal stenosis. Split-thickness skin grafts have been used for epithelial coverage. Depending on the size and location of the canal defect, one of three graft types was used: island, segmental, or circumferential. Surgical techniques are discussed and illustrative cases presented. Long-term graft results have been excellent, with no patient requiring a second graft for coverage. In those patients with preoperative conductive losses, the average improvement in hearing threshold was 27 decibels.

Adult↗
PubMed1995

Chronic otitis media and sensorineural hearing loss: is there a clinically significant relation?

Previous investigations into the possible relation between chronic otitis media (COM) and sensorineural hearing loss (SNHL) have resulted in differing results and conclusions. A retrospective study was conducted to examine the relation between COM and SNHL, using strict selection criteria for cases so as to eliminate co-variables. In addition, various COM parameters were studied to determine if a correlation with the severity of the SNHL existed. At the University of Virginia, charts of all patients undergoing chronic ear surgery from September 1983 to March 1993 were reviewed. Sixty-nine patients met the following criteria: unilateral COM and no history of head trauma, meningitis, post-traumatic tympanic membrane perforation, labyrinthine fistula, or coexisting otologic condition of either ear. From these charts, audiograms were then analyzed for evidence of SNHL, defined as the difference in preoperative bone conduction thresholds between diseased and control (normal contralateral) ears. Mean bone conduction differences were small: -0.5 dB at 500 Hz, 0.9 dB at 1,000 Hz, 4.4 dB at 2,000 Hz, and 3.6 dB at 4,000 Hz. There were nonsignificant bone conduction threshold differences that trended toward greater SNHL with diseased mucosa and cholesteatoma at 2,000 and 4,000 Hz. There was no consistent correlation between severity of SNHL and presence of otorrhea, degree of ossicular erosion, or duration of disease. The authors conclude that COM may cause SNHL, but in the vast majority of patients this loss is not clinically significant.

Adolescent↗
PubMed1995

Promontory stimulation following translabyrinthine excision of acoustic neuroma with preservation of the cochlear nerve.

Promontory stimulation is an accurate method of assessing the functional integrity of the cochlear nerve by electrical stimulation. This technique is widely used in screening prospective candidates for cochlear implants. Recent reports have confirmed the integrity of cochlear nerve responses to electrical stimulation following labyrinthectomy and unsuccessful hearing preservation attempt by the retrosigmoid approach. In this report, the authors present three patients with intracanalicular acoustic neuromas excised through a translabyrinthine approach in which the cochlear nerve was preserved. In each patient, promontory stimulation elicited repeatable behavioral responses. These responses were consistent over a 9-month period of observation.

Auditory Threshold↗
PubMed1994

Electric auditory brain-stem responses in nucleus multichannel cochlear implant users.

OBJECTIVE: The electrically elicited auditory brain-stem response (EABR) has been proposed as a tool for use in cochlear implant device setting. To systematically examine the relationships of psychophysical perceptions and EABRs, implant users underwent a series of comparative measurements. The characteristics of the EABR were assessed for their predictive value in determining the subjective measures needed to set the implant device. DESIGN: Characteristics of the EABR and various perceptual measures in a group of cochlear implant users served as compared variables in a correlational study. SETTING: The study was carried out in the audiology clinic of a university hospital. The audiology clinic maintained a fully equipped evoked potential laboratory, and was part of an otolaryngology department that supported a cochlear implant program. SUBJECTS: The subjects consisted of 10 consecutively selected postlinguistically deafened adult multichannel cochlear implant users. MAIN OUTCOME MEASURES: Morphology, latency, and amplitude measures of the EABR recordings were compared with behavioral perceptions of threshold, most comfortable and uncomfortable loudness levels. RESULTS: Perceptual measures of threshold were found to be significantly related to the threshold of the EABR across subjects and electrode position. Simple linear regression analysis was used to measure the degree of the relationship. An r value of 0.89 attests to a significant relationship. The EABR wave latencies and amplitudes were found to have no significant relationship to any of the perceptual measures examined. CONCLUSIONS: Although EABR cannot replace behavioral measurements for device setting, in difficult cases EABR thresholds may be used as a starting point from which to estimate settings for the device.

Adult↗
PubMed1994

Inner ear hair cell regeneration in a mammal: identification of a triggering factor.

Recent observations have shown that mammals possess a limited capacity for regeneration of inner ear sensory epithelia. It is clear, however, that a mitogenic growth factor will be necessary to up-regulate this capacity before clinical application becomes feasible. This study used in vitro cultures of adult mouse vestibular organs for assessing the mitogenic effect of transforming growth factor alpha (TGF-alpha). Sixty-one utricles and cristae were maintained in culture for 7 to 8 days. Neomycin was used to damage the hair cells. Autoradiography permitted identification of any cell which had undergone mitosis during the culture period. The proliferative response was compared in organs exposed to TGF-alpha and those maintained in the basic culture medium only. The results demonstrated that TGF-alpha significantly increased cell proliferation in the sensory epithelia and also in the marginal zones surrounding them. This finding provides a scientific basis for the concept that inner ear hair cell damage in humans may someday be reversible pharmacologically.

Animals↗