Three-dimensional bone CT reconstruction anatomy of the vidian canal

OBJECTIVES

To examine the anatomical features of the anterior opening of the vidian canal using three-dimensional (3D) computed tomography (CT) images of the bone.

METHODS

We reviewed 62 patients who had undergone bilateral vidian neurectomies. One hundred and twenty-four vidian canals and their surrounding anatomies were analyzed. 3D images were reconstructed using algorithms and compared with conventional two-dimensional (2D) CT images.

RESULTS

A bony prominence that overlaid the vidian canal along the sphenoid sinus floor was found in 60 (48.39 %) canals. Pneumatization of the pterygoid process was observed in 45 sides (36.29%). No significant discrepancy was found in detecting these variances between the 2D and the 3D images. The presence of a surgically favorable gap between the palatine and the sphenoid bone was seen in 25 sides (20.16%) without significant association with pterygoid process pneumatization or vidian canal protrusion. This gap was not identified on the 2D CT scans.

CONCLUSION

3D CT reconstruction images of bone provide superior delineation of the gap between the palatine and the sphenoid bone, which is a critical variation for vidian neurectomy. This useful method may contribute to better prediction and guidance of the surgical approach to the vidian canal and pterygopalatine fossa.

White-light electroluminescence from ZnO nanorods/polyfluorene by solution-based growth

We report bright white-light electroluminescence (EL) from a diode structure consisting of a ZnO nanorod (NR) and a p-type conducting polymer of poly(fluorine) (PF) fabricated using a hydrothermal method. ZnO NRs are successfully grown on an organic layer of PF using a modified seeding layer. The EL spectrum shows a broad emission band covering the entire visible range from 400 to 800 nm. White-light emission is possible because the ZnO-defect-related emission from the ZnO NR/PF heterostructure is enhanced to become over thousand times stronger than that from the usual ZnO NR structure. This strong green-yellow emission associated with the ZnO defects, combined with the blue PF-related emission, results in the white-light emission. Enhancement of the ZnO-defect emission is caused by the presence of Zn(OH)(2) at the interface between the ZnO NRs and PF. Fourier transform infrared spectroscopy reveals that the absorption peaks at 3441, 3502, and 3574 cm(-1) corresponding to the OH group are formed at the ZnO NR/PF heterostructure, which confirms the enhancement of defect emission from the ZnO NR/PF heterostructure. The processing procedure revealed in this work is a convenient and low-cost way to fabricate ZnO-based white-light-emitting devices.

Extraordinary transmittance in three dimensional crater, pyramid, and hole-array structures prepared through reversal imprinting of metal films

We used a reversal imprinting-in-metal (RIM) process to fabricate various three-dimensional (3D) metal structures under low pressure. Molds featuring different shapes were used to pattern various subwavelength metal structures, including pyramidal, hole-array, and crater-like structures. Refractive index matching and cavity effects both enhanced the degree of transmission of these structured metal films. The crater-like structure appears to be a promising material because of the unique properties imparted by the elongated and gradually tapering spacing of its cavities. From both near-field simulations and experimentally obtained optical spectra, we found that the cavity effect in the crater-like structure led to significantly enhanced transmission of the optical intensity. Thus, this RIM process allows the ready fabrication of various two- and three-dimensional metallic structures for use in surface plasmon-based devices.

Microvascular transplantation and replantation of the dog submandibular gland

Transplantation and replantation of the submandibular gland with microvascular techniques were demonstrated in a previous study, with good gland survival. The application of radiation on the neck bed was attempted to address an actual clinical scenario in this study. Five canine submandibular glands were transplanted using microvascular techniques to the ipsilateral femoral system. Radiotherapy at a dosage level of 3,600 cGy using 600 cGy q.d was delivered to the nasopharyngeal and neck regions 2 weeks after transplantation. The transferred glands were then reintroduced into the original but radiated neck bed. The glands were harvested for histological examination 8 weeks later. Four of five canine submandibular glands can withstand microvascular transplantation and then replantation into a radiated neck bed for at least 8 weeks. However, the salivary function was depleted. The canine submandibular gland can survive the transplantation and replantation for at least 8 weeks in spite of precipitating radiation insult on the neck bed for 3 weeks. Neurorraphy is, however, essential to maintaining the glandular function.

Different risks of symptomatic brain necrosis in NPC patients treated with different altered fractionated radiotherapy techniques

PURPOSE

To report our observation of excessive temporal lobe necrosis in nasopharyngeal carcinoma (NPC) patients treated with 160 cGy b.i.d. radiotherapy technique. During the same period, patients treated with 120 cGy b.i.d. have not shown a similar tendency. Our experience may be useful for designing unconventional radiotherapy regimens for NPC patients.

METHODS AND MATERIALS

During the period from October 1991 to January 1998, 81 M0, previously untreated NPC patients completed altered fractionated radiotherapy. Seventy patients were treated with the hyperfractionated technique, and 11 were treated using the accelerated-hyperfractionated scheme. Hyperfractionated radiotherapy was delivered using 120 cGy b.i.d. separated by 6-h intervals throughout the course. A minimum tumor dose of 8000 cGy was the standard dose over an 8-week period. With the accelerated-hyperfractionated scheme, 160 cGy was given twice daily, also with an interval of 6 h. The minimum tumor dose ranged between 6840 and 7640 cGy, with 7 of the 11 patients receiving 7000 cGy. The arrangement of portals was the same for both regimens. The follow-up period for patients alive was from 32 to 102 months with a median of 61 months for the hyperfractionated patients. For the accelerated-hyperfractionated group, it ranged from 67 to 82 months with a median of 72 months. No patient was lost to follow-up.

RESULTS

At the time of analysis, 49 of the 70 patients in the hyperfractionated group were alive. In the accelerated group, 8 of the 11 patients were alive. The estimated radiation dose to the temporal lobe for the hyperfractionated group was 6000-7440 cGy with a median of 7080 cGy. For the accelerated-hyperfractionated group, the dose range was 4480-6700 cGy with a median of 6400 cGy. Of the 70 patients treated with hyperfractionated radiotherapy, none developed symptomatic brain necrosis, despite the higher total dose to the temporal lobe in general. In contrast, 3 of the 11 (27%) patients irradiated using the accelerated-hyperfractionated regimen suffered from temporal lobe necrosis at 16, 19, and 40 months after completion of radiotherapy.

CONCLUSION

An excessive incidence of temporal lobe necrosis was noted when an accelerated-hyperfractionated regimen with 160 cGy b.i.d. was used in NPC patients with a median brain dose of 6400 cGy. There has been no such event in patients treated using a hyperfractionated regimen with 120 cGy and a median brain dose of 7000 cGy. The real causes of this discrepancy are not known. However, a high sensitivity of the human brain to a change in fraction size may play a role.

The effect of exposure time on microsurgical anastomoses of experimentally crushed arteries

Replantation after crushing amputation has a relatively low success rate. Although the mechanism of trauma is a major factor in failure, the time lapse before vessel anastomosis may also be a contributing factor. In this study, we observed the influence of the interval between vessel injury and surgical treatment on thrombus formation and healing after controlled crushing. Seventy-five Sprague-Dawley rats were used. A segment of femoral artery was clamped to create warm ischemia for 8 hours and crushed with a 15 kg load for one hour. After the loading device was removed the crushed segments were transected and the vessel ends exposed to the adjacent tissues and blood for 0, 2, 4 and 6 hours (groups II-V, respectively) prior to being anastomosed with standard microsurgical technique. The vessel samples were harvested at days 1, 2 and 7, respectively, and evaluated by light microscopy and scanning electron microscopy (SEM). The patency rate of the anastomoses was 97.3% at harvest and reendothelialization was completed at day 7. Three anastomoses with 4 or 6 hours exposure showed thrombosis, or clotting. The results indicated that up to 6 hours exposure time did not have a significant influence on thrombus formation or the healing process of vessels under the controlled conditions of this study.

The selective killing effect of special wavelength light in the treatment of human superficial cancer

The authors discovered that 0.4-micron to 1.1-microns wavelength light can selectively kill superficial cancer tissue in the human body. Light at a density of integral power 1 to 6 W/cm2 will kill tumor but will affect normal tissues less. The model KS-1 phototherapeutic instrument was made according to these principles and used to treat 34 patients who had a variety of cancers, including carcinomas of the oral cavity, skin, and cervix. The 25 cured patients were then monitored for 1 to 4 years. No side effects were found. Currently there are several hospitals in China that use this instrument for the treatment of some kinds of carcinoma.