Possibilities of surgical correction of vocal cord palsy after thyroid gland operations.

INTRODUCTION: Surgery of the thyroid gland remains the main cause of bilateral vocal cord palsy (VCP). Ventilation problem is the main problem in such situations. There are a couple of corrective surgical procedures in the case of VCP. The aim of our study was to show the possibility of widening of the glottis, and to evaluate the techniques and effects of surgical treatments due to bilateral VCP resulting from thyroid gland surgery. MATERIAL AND METHODS: Five methods of surgical treatment were used: laser-assisted posterior cordectomy, according to Denis and Kashima; laser-assisted bilateral medial arytenoidectomy, as proposed by Crumley; laser-assisted posterior ventriculocordectomy, as described by Pia; laser-assisted total arytenoidectomy with posterior cordectomy, as presented by Ossoff; and laterofixation, according to Lichtenberger. The postoperative patient's subjective improvement was assessed using visual analogue scale. RESULTS: Between 1998 and 2014 we operated on 270 patients with bilateral VCP. Paresis occurred as the result of the iatrogenic effect of thyroid gland surgery in 255 patients (94.4%) vs. 15 (7.6%) from other causes. The majority of our patients (77.6%) had undergone laser arytenoidectomy with posterior partial cordectomy, and in 13.7% of them Lichtenberger laterofixation had been performed. Ossoff 's surgery gives good ventilation results: successful decannulation (62.9% after first surgery; 97.6% final rate) and significant subjective ventilation improvement in 96% of patients. CONCLUSIONS: Ossoff 's laser arytenoidectomy with posterior cordectomy is a safe procedure that gives acceptable ventilation improvement. Patients report satisfactory quality of life and the possibility of returning to active professional life. Laterofixation should be considered as an alternative for tracheotomy rather than permanent procedure.

Influence of aging on medial olivocochlear system function.

BACKGROUND: There is still controversy regarding the influence of aging on medial olivocochlear (MOC) system function. The main objective of this study is to measure age-related changes of MOC system function in people with normal hearing thresholds. METHOD: Bilateral assessment of the MOC effect for click-evoked otoacoustic emissions (CEOAEs; at 70±3 dB peak sound pressure level [pSPL], click at 50/second, 260 repeats, 2.5-20 millisecond window) and for distortion product otoacoustic emissions (DPOAEs; with [frequencies] f2/f1=1.22, [levels of primary tones] L1=65 dB SPL and L2=55 dB SPL; DP-grams for 2f1-f2 were collected for the f1 frequencies varying from 977 Hz to 5,164 kHz, with the resolution of four points per octave) was performed in a group of 146 (n=292 ears) healthy, right-handed subjects aged from 10-60 years with a bilateral hearing threshold from 0.25-4.0 kHz, not exceeding 20 dB hearing level; normal tympanograms; and a threshold of the contralateral stapedial reflex for broadband noise (BBN) of 75 dB SPL or higher. The MOC inhibition was assessed on the basis of changes in OAE level during BBN contralateral stimulation at 50 dB sensation level (mean, 65±3 dB SPL). RESULTS: Comparative analysis of the MOC effect for CEOAE and DPOAE showed the weakest effect in the oldest age group (41-60 years) at almost all tested frequencies. Moreover, a weak, albeit significant, positive correlation between the level of OAE and the size of the MOC effect was documented. CONCLUSION: On the basis of our study, we have found a decrease in the strength of the MOC system with increasing age in normally hearing subjects, as reflected by a decrease of the OAE suppression effects in older individuals and an increase of the number of CEOAE and DPOAE enhancements during contralateral acoustic stimulation in the elderly, especially in the high-frequency range.

[Efferent suppression test--sensitivity and specificity]. / Test eferentny slimaka--czulosc i swoistosc metody.

INTRODUCTION: The amplitude of click evoked otoacoustic emissions can be suppressed (reduced) with contralateral acoustic stimulation (CAS). This is thought to be due to the inhibitory control that the medial efferent auditory nerve exerts on outer hair cell function. One commonly used test of medial olivocochlear (MOC) function in humans involves measuring the degree of suppression of ipsilateral otoacoustic emissions (OAEs) by CAS. This effect is called contralateral suppression, efferent effect or olivocochlear reflex. Aim of the study. The objective of this study was to measure cut-off level of contralateral suppression, sensitivity and specificity of the efferent test. MATERIAL AND METHODS: To evaluate the function of MOC system click evoked otoacoustic emissions (CEOAEs) with and without continuous contralateral broadband noise (BBN) stimulation were recorded in 14 patients with multiple sclerosis, 16 patients with unilateral cerebello-pontine angle tumor and control group matched for age and gender. BBN was presented at 50 dB SL and otoacoustic emissions were recorded in response to nonlinear clicks at 70 +/- 3 dB SPL. RESULTS: The cut-off level was established at -1.4 dB. For 1.4 dB cut-off level of contralateral suppression the sensitivity of the efferent test was 90% and specificity was 70%. CONCLUSIONS: To conclude, assessment of efferent suppression may be a useful addition to the battery test employed in the investigation of multiple sclerosis and cerebello-pontine angle tumors. The MOC suppression test may provide a tool for an early diagnosis of the brainstem pathology.