Anatomical study of a surgical approach through the neck to the jugular foramen under endoscopy.

OBJECTIVES: To investigate the feasibility of an endoscopic surgical approach through the neck to the jugular foramen, to determine the relevant techniques and extent of exposure, and to provide a new surgical approach with minimal trauma. METHODS: Nine cadaveric head specimens with attached necks were fixed with 10% formalin solution. Two of the heads were fixed and injected with colored silicone rubber. Through the dissection of these cadaver head and neck specimens, we designed a surgical approach from the neck to the jugular foramen area with the use of a neuroendoscope and performed simulated surgery to determine which anatomical structures were encountered in the approach. RESULTS: The posterior aspect of the internal jugular vein is adjacent to the rectus capitis lateralis. The internal carotid artery is anteromedial to the internal jugular vein, with the glossopharyngeal nerve, accessory nerve, vagus nerve and hypoglossal nerve in between. Removal of the rectus capitis lateralis can reveal the jugular process, and exposing the space between the superior oblique muscle and the jugular process can reveal the atlanto-occipital joint. Drilling through the occipital condyle can facilitate entrance into the skull, expose the flank of the medulla oblongata, and reveal the medullary olive and accessory nerve, vagus nerve, hypoglossal nerve, vertebral artery and posterior inferior cerebellar artery. Removing the jugular vein and completely opening the posterior wall of the jugular foramen can expose the inferior wall of the jugular bulb and the inferior wall of the sigmoid sinus. Drilling through the styloid process, which is lateral to the internal jugular vein, can expose the lateral area and upper wall of the jugular bulb and cranial nerves (CN) IX-XII; and near the top of the jugular bulb, the tympanic cavity and the external auditory canal can be easily opened. CONCLUSION: Endoscopic surgical access from the neck to the jugular foramen is feasible. This surgical approach can simultaneously remove intracranial and extracranial tumors and can also be used to remove tumors in the ventral region of the occipital foramen and the hypoglossal canal. Furthermore, this approach is advantageous in that minimal trauma is inflicted. With judicious patient selection, this approach may have significant advantages and may be used as a primary or secondary surgical approach in the future. Nonetheless, this approach is still in development in a laboratory setting, and further research and improvements are needed before facing more complicated situations in clinical practice.

Serum dioxin levels in residents living in the vicinity of municipal waste incinerators in Taiwan.

This study used data obtained from the Taiwan Environmental Protection Administration to measure the dioxin exposure and the body burden for residents living in the vicinity of 19 municipal waste incinerators (MWIs). A survey was conducted in 1999-2003 for the residents. Approximately 16 ambient air samples and a 60-ml blood samples of 84 to 92 residents aged 18-65 yr were collected randomly in four zones (A, B, C, D) for each MWI site based on the atmospheric dispersion model (ADM). Zone A was defined with the highest pollution level, followed by zones B and C, and zone D (background level). Congeners of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined for each sample. We summarized the PCDD/Fs levels in air samples and serum specimens by zone for these 19 sites. The mean ambient levels of PCDD/Fs fitted the ADM, the highest from zone A and the lowest from zone D (2.74 vs. 0.13 pg I-TEQ/Nm3). However, the mean serum concentration in zones A was not distinct from that in zones D (18.7 vs. 19.0 pg WHO-TEQ/g lipid). The age-specific average serum concentration increased from 13.27 pg WHO-TEQ/g in 18- to 25-yr-old subjects to 23.46 pg WHO-TEQ/g lipid in 56- to 65-yr-old subjects. In conclusion, the serum PCDD/Fs levels among residents did not adhere to the dispersion model for incineration emissions. The dose-response of serum PCDD/Fs by age suggests that the body burden of the chemicals is mainly associated with other sources instead of with inhalation.