Our recent studies of the human frontal sinus indicated that occurrence of naso-paranasal inflammation is greatly affected by the extent of sinus development.
The authors studied 74 human frontal sinuses in 61 cases whose age ranged from fetus to 80 years old in order to study the process of pneumatization in the frontal sinus and the etiology of recurrent frontal sinusitis. The conclusions drawn may be summarized as follows:
1. Pneumatization activity of the frontal sinus is mainly dependent upon two major factors. One is proliferation of connective tissue between the mucous membrane and the periostium (submucous connective tissue), which plays an active role in pneumatization and the other is the size of marrow space in the frontal bone. The frontal sinus appeared to develop when the frontal bone has a well developed marrow space plus proliferation of the submucous connective tissue extending into the marrow space. The pneumatization process will be suppressed either when the frontal bone contains underdeveloped marrow space or when proliferation of the submucous connective tissue is depressed.
Heredity, disposition, endocrine activity, local inflammation and local mechanical factors may affect the extent of pneumatization.
2. The authors studied the specimens in regards to the etiology of recurrent frontal sinusitis and deduced that postoperative derangement of the pneumatization process in the frontal bone could be responsible for the condition.
Many specimens showed small ducts that communicated with the frontal sinus and the marrow space located above the frontal sinus.
Submucous connective tissue was often seen to extend into the marrow space through these small ducts. Transformation of the bone at the roof of the frontal sinus for pneumatization seemed to be accomplished in this manner.
Frontal sinusectomy with radical removal of the submucosal tissue may cause obstruction of those small ducts which could leads to recurrent frontal sinusitis provided pneumatization proceeds in the isolated marrow space.
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