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  • By Author: Akiyama, Masahiko x
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Satoshi Tani, Hiroyasu Nagashima, Akira Isoshima, Masahiko Akiyama, Hiroki Ohashi, Satoru Tochigi and Toshiaki Abe

Object

To perform interbody distraction and to obtain spinal curvature correction during anterior cervical discectomy and fusion (ACDF), the authors recently adopted a new stand-alone device, a disc space–fitted distraction device (DFDD). In this preliminary report the authors introduce this unique device and discuss some advantages in terms of short-term clinical and radiological evaluations.

Methods

The most unique aspect of the DFDD is the function of gentle distraction at anterior disc space with maximum lordotic correction of up to 8° while rotating a screw at the front of the device. Additional advantages are related to its configuration such as disc space–matched shape in all dimensions, tapering contour for easy insertion into the disc space, multiple spikes to avoid dislodgment, wider contact area to the vertebral endplate for diminishing sinking process, and sufficient space for accommodation of bone-conductive materials. Twenty-four patients who have been observed more than 12 months after ACDF were involved in this evaluation.

Results

The objective clinical outcome, measured by the Neurological Cervical Spine Scale, was significantly improved. In radiological evaluation, statistically significant improvement compared with preoperative values was noted on the curvature index, C2–7 curvature, and disc angle (p < 0.01) throughout the entire postoperative period, up to 12 months. A high fusion rate and remodeling process around the implants were also observed.

Conclusions

The DFDD may have some advantages over other devices—its distraction action, diminished sinking, and early solid bone union resulted in maintaining sufficient correction of the spinal curvature. This corrected spinal curvature may play an important role in preventing progressive adjacent-disc degeneration subsequent to ACDF in the long term.

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Hisashi Onoue, Nobuyoshi Kaito, Masahiko Akiyama, Masato Tomii, Shogo Tokudome and Toshiaki Abe

✓ To investigate the effects of subarachnoid hemorrhage (SAH) on the responsiveness of human cerebral arteries to vasoactive substances, the authors measured the isometric tension generated in helical strips of basilar and middle cerebral arteries isolated from human cadavers Contractions caused by KCl, prostaglandin F, noradrenaline, and serotonin were reduced in arteries obtained from cadavers with aneurysmal SAH damage and compared to those obtained from cadavers with no indication of intracranial diseases. Endothelium-dependent relaxation elicited by substance P and bradykinin, and endothelium-independent relaxation induced by prostaglandin I2 and nitroglycerin were also markedly decreased in arteries affected by SAH. However, the reduction in relaxation response to prostaglandin I2 was significantly less than that to the other vasodilator agents. These results indicate that human cerebral artery functions are severely impaired after SAH and that poor responses to vasoactive agents may result primarily from dysfunction of smooth-muscle cells.