Biomedical subjects

J G Feghali

Publications and source records attributed to J G Feghali.

12 recordsLinked to original sources

PubMed1992

Pain after surgery for acoustic neuroma.

Postoperative pain after surgery in the cerebellopontine angle (CPA) is acknowledged to occur, but is rarely taken into account as a factor in the analysis of morbidity of such surgery. It is widely acknowledged that some patients, having undergone such surgery, particularly by means of the suboccipital approach, report significant post-operative pain and headache. This study was undertaken to determine the incidence and severity of pain after excision of acoustic neuromas and to establish whether this differed between the suboccipital and translabyrinthine routes. Ninety-one percent of all patients (n = 58), who had the suboccipital approach used for removal of their tumor, were surveyed. A smaller group (n = 40), matched for tumor size, age, and sex, but in whom the translabyrinthine approach was used, was similarly studied. A standard questionnaire, designed to detect and quantify postoperative pain, was administered to each patient. Of patients who underwent tumor excision by means of the suboccipital approach, 63.7% experienced significant local discomfort and headache, whereas this was notably absent in all those who had undergone translabyrinthine excision. In view of the significant morbidity noted to follow the suboccipital approach, several modifications of the surgical technique used were devised.

Activities of Daily Living↗

PubMed1991

A new approach to serial monitoring of ultra-high frequency hearing.

Early detection of drug-induced hearing loss is best accomplished by monitoring hearing at the ultra-high frequencies. Unfortunately, at these frequencies, sound pressure at the tympanic membrane (TM) critically depends on the placement of the sound source and on the size and shape of each individual external ear. Thus, presentation of the same sound may yield substantially different sound pressures in different ears. Moreover, only a slight change in the position of an earphone may yield large changes in sound pressure at the tympanic membrane. As a consequence of these characteristics, the reliability of ultra-high-frequency audiometry is poorer than at conventional audiometric frequencies. However, for the early detection of ototoxicity, it is necessary only to monitor for increases in thresholds. Accordingly, a sound-delivery system was developed which fixes the relative position of the sound source and the ear. This system ensures that sounds at the same level may be presented during different test sessions. To assess the stability of ultra-high-frequency thresholds, normal hearing subjects were tested in sessions separated by several weeks. Thresholds were obtained between 1 and 16 kHz and were found to be reliable. It is concluded that this type of system can be used for monitoring the ototoxic effects of drug therapy.

Acoustics↗

PubMed1991

Static flicker perimetry in glaucoma and ocular hypertension.

The visual threshold for standard and flickering targets was determined and compared in 8 glaucoma patients, 8 glaucoma suspects and 13 normal controls. Using a Goldmann size III standard white light target, 25 points in the central 30 degrees of the visual field were tested. The location of these points was designed to reflect areas of the visual field commonly affected by glaucomatous damage. The same determinations were then repeated with the test target flickering at 25 Hz. All glaucoma patients had elevation of the visual threshold compared to normal controls for both standard and flickering targets. The absolute value of threshold elevation was not significantly different between standard and flickering lights. However, when larger targets were used, flicker thresholds were an average 8 dB higher (p less than 0.05) in the glaucoma patients compared to the normals, suggesting improved identification of glaucomatous damage with the use of larger flickering targets.

Adult↗

PubMed1991

Effect of short-term intraocular pressure elevation on the rabbit electroretinogram.

Pattern electroretinograms (PERGs), with a presumed ganglion cell origin, and oscillatory potentials (OPs), with a presumed inner retinal origin, are reduced in glaucoma. Flash ERGs are reduced at intraocular pressures (IOPs) greater than 60 mm Hg. A study was designed to investigate the time-course of change in PERGs, OPs, and flash ERGs after increasing the IOP of ten rabbit eyes to 35-45 mm Hg by using a suction-cup apparatus. Although flash ERG b-wave amplitude was unchanged (P = 0.32), PERGs were reduced (P less than 0.001) immediately after IOP elevation, as were OPs (P = 0.03). Both PERG and OP amplitudes returned to normal immediately after normal IOP was restored. This study showed that the rabbit is a suitable model for studying PERGs. It also suggested that moderate IOP elevation for 10 min reversibly impaired ganglion cell and inner retinal function in the rabbit, although more external function was unchanged.

Animals↗

PubMed1990

Visual function deficits in glaucoma. Electroretinogram pattern and luminance nonlinearities.

The pattern electroretinogram is abnormal in glaucoma. Part of the pattern electroretinogram may be attributed to the summation of responses to luminance increases and decreases (nonlinear luminance responses). We conducted a study to investigate the effect of glaucoma on the pattern electroretinogram component waves and to determine if the flicker electroretinogram nonlinear components are abnormal in glaucoma. We tested 35 subjects in two replications of four conditions: 10- and 20-Hz flicker, and 4- and 10-Hz pattern reversal. Only the even harmonics were recorded. The patients with glaucoma had reduced electroretinogram amplitudes for all measures relative to the normal subjects. Electroretinogram amplitudes of those suspected of having glaucoma were intermediate. The greatest amplitude reductions were for the 10-Hz flicker electroretinogram and the 4-Hz pattern electroretinogram. These results confirm pattern electroretinogram abnormalities and reveal flicker electroretinogram abnormalities in glaucoma.

Adult↗

PubMed1990

Consequences of middle ear bone dust during neurotologic surgery.

Most otologists are cautioned at some point in their training that if bone dust is allowed to enter the middle ear while the mastoid is being drilled, there may be adverse consequences. Two cases of ossicular fixation and conductive hearing loss after retrolabyrinthine vestibular nerve section prompted us to examine the issue of bone dust in the middle ear. In a study of 13 temporal bones that had undergone neurotologic surgery, we found 11 that showed evidence of viable bone dust in the middle ear, and three that had ossicular fixation. Viable bone dust was always encased in a mucous membrane lining. These findings suggest that bone dust that enters the middle ear may indeed remain viable and cause ossicular fixation. The surgeon should therefore take every precaution to prevent bone dust from entering the middle ear during neurotologic procedures in which conservation of hearing is attempted.

Bone and Bones↗

PubMed1988

Uvulopalatopharyngoplasty in a child with obstructive sleep apnea. A case report.

Uvulopalotopharyngoplasty (UPPP) has been recently popularized for the treatment of snoring and sleep apnea syndrome (SAS). All reported cases so far have been adults and the use of this procedure in the pediatric age group has not as yet been reported. Obstructive sleep apnea in children has been classically treated previously either medically or by adeno-tonsillectomy. The case of a three year old child with obstructive sleep apnea secondary to a large uvula and a redundant soft palate is reported. The child was successfully treated by UPPP, and remained free of symptoms for a follow-up period of one year.

Child, Preschool↗

PubMed1988

A comparison of betaxolol and timolol in open angle glaucoma and ocular hypertension.

In a randomized, double-masked study, 41 patients with primary open-angle glaucoma or ocular hypertension were treated with betaxolol 0.5% or timolol 0.5% drops for 26 weeks. The average decrease in intraocular pressure (IOP) over the total study period was significant with both betaxolol (-6.3 mmHg) and timolol (-7.2 mmHg) in patients receiving no adjunctive therapy. There was no difference between betaxolol and timolol with respect to changes from baseline IOP. Significantly decreased mean brachial arterial pressure (MAP) was seen only with timolol, although the difference between the two groups was not significant. Pulse, pupil size, and basal tear secretion were unchanged in both groups. Burning upon instillation of the drops was more frequent with betaxolol.

Adrenergic beta-Antagonists↗

PubMed1986

Comparative aqueous outflow facility measurements by pneumatonography and Schiotz tonography.

Tonography was performed on 36 eyes of 15 normal and 3 primary open angle glaucoma patients using pneumatonography and classical Schiotz tonography. The average values of the coefficient of outflow facility (C) for the whole sample were virtually identical with both methods. However, both intersubject and interobserver variability were significantly higher with penumatonography. Although both methods provide comparable aggregate estimates of aqueous outflow facility, we think that Schiotz tonography is more reliable than pneumatonography because of the greater mechanical stability of the Schiotz instrument on the eye. On the other hand, pneumatonography offers the advantage of a shorter test period (2 min instead of 4).

Adult↗

PubMed1985

Decreased intraocular pressure in the hypertensive human eye with betaxolol, a beta 1-adrenergic antagonist.

In a double-masked randomized prospective study, 19 adult white subjects with primary open-angle glaucoma or ocular hypertension were treated twice daily with drops of 0.25% betaxolol (a relatively selective beta 1-adenoceptor antagonist) or placebo for six weeks. The nine betaxolol-treated subjects demonstrated a statistically significant average decrease in intraocular pressure of 3.8 +/- 5 mm Hg, evident after one week and persisting throughout the entire six-week treatment period. The ten placebo-treated subjects exhibited a statistically nonsignificant increase in intraocular pressure of 0.4 +/- 2.4 mm Hg. Mean systemic arterial blood pressure, pulse rate, corneal sensitivity, pupil diameter, and basal tear secretion remained unchanged in both groups. Transient stinging upon instillation of the eyedrops was the only side effect in the betaxolol-treated subjects but in no case did it necessitate cessation of therapy.

Adrenergic beta-Antagonists↗

PubMed1985

Is the endolymphatic sac always accessible?

All surgical manipulations of the endolymphatic sac have a common requirement: to identify the intradural part. We studied the position of the intradural endolymphatic sac in relation to the posterior semicircular canal, the sigmoid sinus, the retrofacial air cell tract, and the jugular bulb in 50 temporal bones. The intradural sac was identifiable in 48 cases; in two the sac either was absent or would not have been identifiable surgically without jeopardizing other important structures, particularly the posterior semicircular canal.

Ear, Inner↗

PubMed1985

Residual high-frequency hearing in a patient with Mondini's deformity: clinical implications.

We reviewed records of a patient with Mondini's deformity who had hearing loss in the speech frequencies and preservation of hearing for frequencies above 4000 Hz. The patient seemed to be an example of a profoundly deaf child with good speech development secondary to preservation of ultra-audiometric hearing. We suggest that patients with Mondini's deformity have their ultra-audiometric hearing evaluated, and that those with profound deafness and ultra-audiometric hearing be radiographically evaluated to rule out Mondini's deformity for diagnostic and therapeutic purposes.

Auditory Threshold↗