Yasushi Iwashita

Atlantoaxial transarticular screw fixation for a high-riding vertebral artery.

Study Design. The feasibility of inserting a screw for the narrow isthmus with a high-riding vertebral artery was evaluated in patients subjected to posterior atlantoaxial transarticular screw fixation. Objective. To demonstrate the feasibility of inserting bilateral screws and obtaining a stable atlantoaxial complex for patients with a high-riding vertebral artery. Summary of Background Data. Posterior atlantoaxial transarticular screw fixation entails the potential risk of vertebral artery injury, which may be lethal. The risk is much higher for the narrow isthmus caused by a high-riding vertebral artery, and many authors recommend that the procedure should be abandoned if the isthmus is too narrow. On the other hand, bilateral screw fixation is stronger than unilateral screw fixation. Methods. For this study 27 consecutive patients who submitted to atlantoaxial transarticular screw fixation were evaluated before surgery for the position of the vertebral artery grooves using computed tomography (CT) reconstruction. Seven of the patients were defined as having a unilateral high-riding vertebral artery. For these patients, bilateral screw insertion through the most posterior and medial part of the isthmus was performed. Results. No massive bleeding or major complications were encountered in any patients with a high-riding vertebral artery. Postoperative computed tomography reconstruction demonstrated that five of the screws cleared the vertebral artery groove successfully, and two slightly breached it. No screws penetrated into the vertebral artery groove. Conclusions. It is possible to insert a screw safely, even into the narrow isthmus with a high-riding vertebral artery, if the surgeon realizes where the screw should be inserted and has the requisite insertion technique. Bilateral screw fixation should provide a high fusion rate.

Diplopodia with reversed foot: Normal gait after operation at 8 years of age

Diplopodia with the duplicated foot tucked up posteriorly, was reconstructed successfully in an 8-year-old boy. The knee joint, fibula and tibia were uninvolved; he had been walking on the dorsum of the foot wearing an ordinary shoe with the heel forward. The foot had ten toes, nine metatarsals and nine tarsal bones including one talus and one large calcaneus on which two Achilles tendons were inserted into two tuberosities. The lateral supernumerary foot was excised and the medial foot was dorsiflexed by almost 180 degrees by massive release and elongation of tendons. He could walk on his bare reconstructed foot without a brace 10 months after the operation.

Effects of continuous intravenous infusion of MCI-186 on functional recovery after spinal cord injury in rats.

We investigated the effects of a free radical scavenger, MCI-186 (edaravone), on neuroprotection in the rat post-traumatic spinal cord using various doses and routes of administration. The injury was produced with a weight-drop device. Lipid peroxide formation in the spinal cord was measured using the thiobarbituric acid test for malonyldialdehyde (MDA). In the first experiment, MDA production in the untreated post-traumatic spinal cord reached peak values at 1 h post-trauma, and gradually decreased to control levels in 7 days. In the second experiment, rats received twice-daily injections (0, 1, 3, 5, 10, or 20 mg/kg) for 3 days. We found that 3 mg/kg was most effective functionally and histologically. In the third experiment, rats received a 3 mg/kg bolus + continuous infusion (0, 1.5, 2.4, or 3.0 mg/kg/h) for 1, 2, 4, and 8 h. We found that a 3 mg/kg bolus + infusion of 3.0 mg/kg/h was most effective for the inhibition of MDA production. In the fourth experiment, a 3 mg/kg bolus given once immediately after injury and twice daily for 3 days, a 3 mg/kg bolus + 3.0 mg/kg/h for 1 day, or a 3 mg/kg bolus + 3.0 mg/kg/h for 3 days were administered. The continuous infusion for 1 day showed significant improvement functionally and histologically, but continuous infusion at the same rate for another 2 days did not show any further improvement. To effectively reduce secondary neuronal damage, strong inhibition of free radical chain reactions at the early stage, particularly within the first 24 h post-trauma, is important.