Morphology of nerve endings in vocal fold of human newborn.

Sensory receptors are distributed throughout the oral cavity, pharynx, and larynx. Laryngeal sensitivity is crucial for maintaining safe swallowing, thus avoiding silent aspiration. Morphologic description of different receptor types present in larynx vary because of the study of many different species, from mouse to humans. The most commonly sensory structures described in laryngeal mucosa are free nerve endings, taste buds, muscle spindles, glomerular and corpuscular receptors. This study aimed at describing the morphology and the distribution of nerve endings in premature newborn glottic region. Transversal serial frozen sections of the whole vocal folds of three newborns were analyzed using an immuno-histochemical process with a pan-neuronal marker anti-protein gene product 9.5 (PGP 9.5). Imaging was done using a confocal laser microscope. Nerve fiber density in vocal cord was calculated using panoramic images in software Morphometric Analysis System v1.0. Some sensory structures, i.e. glomerular endings and intraepithelial free nerve endings were found in the vocal cord mucosa. Muscle spindles, complex nerve endings (Meissner-like, spherical, rectangular and growing) spiral-wharves nerve structures were identified in larynx intrinsic muscles. Nervous total mean density in vocal cord was similar in the three newborns, although they had different gestational age. The mean nerve fiber density was higher in the posterior region than anterior region of vocal cord. The present results demonstrate the occurrence of different morphotypes of sensory corpuscles and nerve endings premature newborn glottic region and provide information on their sensory systems.

Analysis of hearing preservation and facial nerve function for patients undergoing vestibular schwannoma surgery: the middle cranial fossa approach versus the retrosigmoid approach--personal experience and literature review.

OBJECTIVE: To compare hearing preservation and facial nerve function outcomes in patients undergoing vestibular schwannoma surgery performed using either the middle cranial fossa approach (MCFA) or the retrosigmoid approach (RSA). MATERIALS AND METHODS: A review of the medical records of patients diagnosed with vestibular schwannoma who underwent surgical tumor removal in a single reference center via the MCFA or the RSA between January 1988 and December 2008 was conducted. RESULTS: During this period, 90 patients underwent surgery via the MCFA while 86 patients received surgical treatment via the RSA. Of the patients subjected to the MCFA, 80.7% were characterized by a House-Brackmann (HB) grade I or II outcome, whereas 96.5% of patients undergoing the RSA were characterized by a HB grade I or II outcome (p = 0.001). This difference appeared only for extrameatal tumors when we compared size-matched tumors (58.3% MCFA vs. 98% RSA; p = 0.0006). There was no statistically significant difference in the hearing outcomes upon consideration of hearing preservation as characterized by the modified Sanna classification system involving classes A and B (18.9% MCFA vs. 10.6% RSA; p = 0.122). CONCLUSION: No statistically significant difference in hearing preservation was identified when comparing tumors operated upon via the MCFA versus the RSA. However, our results indicate that a higher risk of facial nerve function impairment exists if the surgery is performed via the MCFA under circumstances where the tumor extends to the cerebellopontine angle.