Lost or fragmented bony septum of the optic canal facing the sphenoid sinus: a histological study using elderly donated cadavers.

PURPOSE: To histologically describe a direct contact (the so-called dehiscence) of the optic nerve (ON) and/or internal carotid artery (ICA) to the mucosa of posterior paranasal sinuses represented by the sphenoid sinus (SS). METHODS: Observations of histological sections of unilateral or bilateral skull bases (parasellar area and orbital apex) from 22 elderly cadavers were made. RESULTS: A bony septum was less than 300 µm between the SS and ICA and 200 µm between the SS and optic nerve. Parts of the septa were sometimes absent due to fragmentation and holes of the bony lamella (2/22 facing the ICA; 4 facing the ICA in combination with an absent bony septum facing the nerve). In these dehiscence sites, the SS submucosal tissue attached to a thick sheath (50-100 µm in thickness) enclosing the optic nerve and ophthalmic artery and/or the ICA adventitia (50-200 µm in thickness). The ICA sometimes contained a sclerotic plaque that attached to or even protruded into the SS. With or without dehiscence, the SS mucosa was always thin (50-100 µm in thickness) and accompanied no mononuclear cellular infiltration or tumor. CONCLUSIONS: A thin bony septum of the optic nerve or ICA had been notable as a danger point during surgery, but even a 0.05-mm-thick bone lamella might be an effective barrier against cellular infiltration or bacterial invasion from the SS. Fragmentation and holes of the bony lamella in 4 cadavers might allow cellular invasion to the optic nerve. Accordingly, unknown immunological cross talks might occur to cause demyelination.

Cervical nerve roots and the dural sheath: a histological study using human fetuses near term.

We have previously reported that the thoracolumbar posterior nerve root shows a tortuous epidural course, based on studies of human fetuses near term. For comparison with the cervical nerve, examinations were conducted using frontal, sagittal and horizontal sections of cervical vertebrae from 22 fetuses at 30-38 weeks of gestation. The cervical nerve root showed a short, straight and lateral course near the zygapophysial joint. Multiple rather than single bundles of the cervical posterior root seemed to account for the majority of sensory nerve fibers innervating the upper extremity. Fasciculation of rootlets was evident near the thoracolumbar spinal cord, whereas it was seen in the dural pocket at the nerve exit from the dural sac although both sites were subdural. As in the thoracolumbar region, the nerve sheath was continuous with the dura mater and independently surrounded each of the anterior and posterior roots. Radicular arteries were few in the cervical region. In 2 of the 22 fetuses (31 weeks and 33 weeks), there was a segmental, unilateral abnormality of nerve rootlet fasciculation where the dorsal root ganglion was located lateral or peripheral to the intervertebral region. Long nerve roots running inferiorly are a necessary adaptation to the delayed and marked growth of the thoracolumbar vertebral column. In children, the cervical nerve roots are likely to be affected by movement or dislocation of the vertebrae. The segmental abnormality of the cervical nerve root may be linked to rare variations in the brachial plexus.

Efficacy and safety of a vessel sealing system in oral cancer resection and reconstructive surgery.

OBJECTIVE: Currently, many studies are being performed that focus on the efficacy and safety of the vessel sealing system (VSS) in various fields of surgery. However, in the field of oral cancer surgery, the efficacy and safety of VSS use have not been clarified. METHODS: One hundred and fifty-one patients underwent oral cancer resection and reconstructive surgery. They were divided into two groups: Ligasure vessel sealing system (LVSS) group and conventional surgery (CS) as control. Intra-operative blood loss, operating time, and incidence of post-operative complications and recurrence were analyzed. RESULTS: LVSS use significantly reduced intra-operative blood loss. The operating time was shortened only in mandibular gingiva cancer surgery. There were no differences between the two groups with regard to the incidence of post-operative complications and recurrence. CONCLUSIONS: LVSS use was found to be effective and proved to be efficient and safe, and may be useful in oral cancer surgery.