Electron microscopy study of peripheral nerves in the uvulae of snorers and obstructive sleep apnoea patients.

HYPOTHESIS: The pathophysiology of snoring and obstructive sleep apnoea is still unclear. Two theories are proposed. The first is the obstructive theory, which postulates palatopharyngeal muscle hypertrophy leading to airway narrowing; there is no neural role. The second is the neurogenic theory, which postulates neural degeneration due to vibratory stretch trauma, leading to muscle atrophy and collapse. As identification of nerve fibres in the uvula and palate is difficult and time-consuming, all previous studies aiming to differentiate between these two theories have been based on indirect observation of the muscles, rather than direct study of the nerves. METHODS: We conducted a prospective study to directly observe and study nerve fibres in uvular specimens from 10 cases of obstructive sleep apnoea, compared with specimens from 10 cases of simple snoring, using transmission electron microscopy. Five autopsy cases served as controls. RESULTS: Obstructive sleep apnoea was associated with definite degenerative changes in myelinated and unmyelinated nerve endings. These degenerative changes were present to a lesser degree and in a smaller proportion of cases of simple snoring. CONCLUSION: The events postulated by the neurogenic theory of obstructive sleep apnoea appear to play an important role in the pathophysiology of snoring and obstructive sleep apnoea.

[Morphologic and ultrastructural changes of soft palate in patients who underwent palatopharyngoplasty]. / Rilievi istopatologici ed ultrastrutturali del palato molle in pazienti sottoposti ad intervento di palatofaringoplastica (PPP).

In order to clarify pathogenesis of Obstructive Sleep Apnea Syndrome (OSAS) in patients with anatomic abnormalities of upper airways, we studied soft palate and uvula of OSAS patients by means of histological and ultrastructural techniques. 38 OSAS patients, severe and moderately severe form, underwent modified Palatopharingoplasty. We evaluated only 16 OSAS patients' soft palate and uvula and observed histological changes in all of them: submucosal edema and minor salivary glandes ipertrophy and iperplasy are present. On the contrary, ultramicroscope showed normal muscle fibers. Strie Z alterations and sarcomeres disorganization, although present, have no statistical value. Very probably, ronflement and apneas determined the observed alterations through trauma on pharingeal wall. Therefore, they are not OSAS primary cause.

A crypto-lymphatic unit at the uvula of the monkey Macaca fascicularis. A light- and electron-microscopic study.

A crypto-lymphatic unit was observed at the left lateral aspect of the uvula of a mature female monkey, Macaca fascicularis. A light- and transmission electron-microscopic investigation revealed that the lumen of the crypt was filled with bacteria, desquamated epithelial cells, lymphocytes and neutrophils. The non-keratinized stratified squamous epithelium of the crypt was fragmented and showed heavy mononuclear cell infiltration and surface discontinuities, exposing lymphoid cells to foreign material. The lymphatic parenchyma consisted of organized lymphatic tissue including germinal centres. The resident cell population included lymphocytes of varying size, blastforming B- and T-lymphocytes and two types of reticular cells resembling the fibroblastic reticulum cell and the follicular dendritic cell, respectively. Occasionally granulocytes were encountered. At its base and laterally the crypto-lymphatic unit was ensheathed by a thin connective tissue capsule. Three other monkeys of the same species failed to reveal similar structures at the same site.