Delayed facial palsy following laser stapedectomy: in vitro study of facial nerve temperature

Delayed facial palsy following conventional stapes surgery is a rare event, but this complication appears to be more common when a laser is used. We have investigated the temperature in the facial canal during stapes surgery using a KTP laser or a microdrill in preserved human temporal bones. Thermocouples were placed in the facial canal and under the foot plate. The results show maximum rises in temperature of between 1.4 degrees C and 15.2 degrees C in the facial canal during laser surgery (mean 6.1 degrees C, SD 4.5 degrees C), but only between 0.45 degrees C and 2 degrees C during procedures in which a microdrill was used (mean 0.9 degrees C, SD 0.9 degrees C) (P = < 0.009). In addition, the facial nerve undergoes repeated heating and cooling cycles during the laser surgery. We conclude that heating of the facial nerve during laser surgery causes oedema, which in turn leads to compression of the nerve within its bony canal.

Phase shifting prior to spatial filtering enhances optical recordings of cardiac action potential propagation

Optical imaging of cardiac electrical activity using a voltage-sensitive dye provides high spatial resolution maps of action potential propagation and repolarization. Charge-coupled-device (CCD) camera-based imaging systems, however, are limited by their low signal-to-noise ratio. We have developed an image processing method to enhance the quality of optical signals recorded using a CCD camera. The method is based on the observation that within a small neighborhood of adjacent pixels, the morphology of the optical action potential varies little except for a phase shift in time resulting from the propagation of the wavefront. The method uses a phase-correlation technique to first correct for this time shift before spatially filtering with a 5 x 5 Gaussian convolution kernel (sigma = 1.179). A length 5 median filter is then applied to further reduce noise by filtering in the temporal domain. The image-processing scheme allows for more accurate extraction of maps of electrical activation, repolarization, and action potential duration.

In vitro evaluation of a malleus head to stapes head 'incus replica' prosthesis

An ossicular prosthesis produced by making a mould from a cadaveric incus and injecting ionomeric cement into it (incus replica prosthesis, IRP) has been cemented to the malleus head and stapes head and evaluated in fresh human temporal bones using a laser vibrometer. Stapes velocity was recorded under acoustic stimulation and foot plate displacements were derived. Fourteen frequencies between 125 Hz and 8000 Hz have been used. Measurements were made with the ossicular chain intact, following removal of the incus, with the prosthesis cemented to the malleus, but not the stapes, and with the incudo-stapedial joint cemented. In a second series of experiments the performance of the IRP was compared with that of a Causse partial ossicular replacement prosthesis, using the same experimental set-up. The results indicate that the prosthesis performs almost as well as the intact ossicular chain and that cementing the incudo-stapedial joint gives better sound transmission than leaving it uncemented. In addition the IRP outperforms the conventional partial ossicular replacement prosthesis.

Fertility and sexual function following orchiectomy and 2 cycles of chemotherapy for stage I high risk nonseminomatous germ cell cancer

PURPOSE

We investigate fertility and sexual function in patients following orchiectomy and adjuvant cisplatin based chemotherapy for high risk, stage I nonseminomatous germ cell tumor of the testis.

MATERIALS AND METHODS

Between 1985 and 1994, 59 patients with stage I nonseminomatous germ cell tumor and poor prognostic factors were treated with 2 cycles of cisplatin, vinblastine and bleomycin, or bleomycin, etoposide and cisplatin after orchiectomy. At least 32 months following treatment all patients were contacted and asked to complete a questionnaire regarding fertility and sexual activity, and to volunteer for a semen and hormonal analysis.

RESULTS

Of the 59 patients 49 (83%) completed the questionnaire. Before chemotherapy 18 (37%) patients had fathered children, 6 (12%) were involuntarily childless and none had a major sexual dysfunction. After treatment 11 (22%) patients fathered children, and 5 (10%) were involuntarily childless, with 4 involuntarily childless before chemotherapy. There were no significant alterations in sexual function. Semen analysis in 27 patients was normal in 23, and revealed mild oligospermia in 2 and azoospermia in 2. In 18 patients with hormone analysis median values for luteinizing hormone and free testosterone were normal but median value for follicle-stimulating hormone was slightly increased.

CONCLUSIONS

Two cycles of cisplatin based adjuvant chemotherapy do not seem to affect adversely fertility or sexual activity.

Imaging assessment of uncomplicated bladder outflow obstruction

To assess the impact of the use of plain X-ray films and ultrasound examinations on clinical decision-making in patients referred with symptoms of bladder outflow obstruction. Patients with symptoms of bladder outflow obstruction were recruited prospectively. After clinical assessment they underwent standard investigations of plain X-ray of the kidneys, ureters and bladder, and upper and lower urinary tract ultrasound. A management decision was made on the basis of all results. These decisions were then reviewed with specific reference to radiological findings to assess the role of imaging in the decision-making process. A total of 320 men were recruited for the study. X-ray of the kidneys, ureters and bladder detected 10 upper tract calculi, none of which has required active intervention to date. Four bladder calculi were detected. Two of these were also seen on ultrasound scan: one was small and insignificant, the other had caused microscopic haematuria, necessitating cystoscopy regardless of the X-ray findings. Upper tract ultrasound revealed abnormalities and anatomical variants which did not affect management. Four patients had upper tract dilatation but these had already had surgery planned on the basis of other investigations, including residual urine volume determination by lower tract ultrasound. Lower urinary tract ultrasound should be the only routine imaging used in the initial assessment of patients with bladder outflow obstruction, with consequent implications of reduced patient stress and reduced investigation cost.

Risk factors for chronicity in childhood otitis media with effusion

One hundred and ninety-one children who presented to the author's clinic with otitis media with effusion (OME) over a 2-year period (1986-1988) have been studied prospectively. Resolution of their OME was considered to have occurred when they had normal findings on pneumatic otoscopy, tympanometry and audiometry on at least two occasions 6 months apart and had subjectively normal hearing in between. The number of operations performed during the course of the disease was used as a surrogate for chronicity. Children with a history of previous aural discharge at presentation were significantly more likely to have chronic OME (P = < 0.02).

A longitudinal study of work load and variations in psychological well-being, cortisol, smoking, and alcohol consumption

The effects of variations in work load (indexed by paid work hours) on psychological well-being, cortisol, smoking, and alcohol consumption were examined in a sample of 71 workers (44 women, 27 men) in the retail industry. Measures were obtained on four occasions over a six-month period, and assessments were ranked individually according to hours of work over the past seven days. Job strain (demand/control) and job social support were evaluated as potential moderators of responses. Paid work hours ranged from a mean of 32.6 to 48.0 hours per week, and ratings of work-home conflict and perceived stress varied across assessments. Salivary cortisol was inversely associated with job strain and did not vary across sessions. Female but not male smokers consumed more cigarettes during periods of long work hours, and self-reported smoking and cotinine concentrations were greater among smokers with higher nicotine dependency scores. Men but not women with poor social supports consumed more alcohol as work hours lengthened. These data indicate that health behaviors are affected only to a limited extent by variations in work load. Results are discussed in the context of adaptation to work and the pathways linking stressful experience with health risk.