Glucose reduces the anticonvulsant effects of the ketogenic diet in EL mice.

The ketogenic diet (KD) is known to be anticonvulsant and anti-epileptogenic. While the mechanism behind this therapeutic benefit is unclear, a reduction of circulating glucose levels through calorie restriction (CR) has been implicated. Foods or drinks that elevate blood glucose are known to compromise the therapeutic benefit of the KD in some children with epilepsy. We therefore evaluated the effect of a calorie restricted KD (KD-R) with supplementation of glucose in the drinking water of EL mice, a natural model of idiopathic generalized epilepsy, prior to seizure testing to assess the effect of glucose on seizure generation. Mice were fed either a standard diet or the KD unrestricted (SD-UR and KD-UR, respectively), or the KD restricted (KD-R). d-Glucose (25 mM) was supplemented in the drinking water of KD-R fed mice for 0.5h or for 2.5h prior to seizure testing. Each restricted mouse served as its own body weight control to achieve a 15-18% body weight reduction. Seizure susceptibility, body weights, and plasma glucose and ß-hydroxybutyrate levels were measured over a nine-week treatment period. Body weights and glucose levels remained high over the testing period in both the SD-UR and the KD-UR groups, but were significantly reduced in all R-fed groups. A significant increase in ß-hydroxybutyrate levels was observed in all KD groups. Seizure susceptibility remained highest in the SD-UR group, was slightly reduced in the KD-UR group, and was significantly reduced after three weeks in all R-fed groups. Supplementation of glucose prior to seizure testing resulted in a decrease of seizure threshold for R-fed mice, but did not alter bodyweight or circulating glucose levels. The KD has both an anticonvulsant and antiepileptogenic effect in EL mice. Here we confirm that CR enhances the anticonvulsant action of the KD in EL mice. Additionally, we show for the first time that supplementation of glucose decreases the anticonvulsant action of the KD, which further supports the hypothesis that CR works through transitioning metabolism from glucose to ketone utilization for energy.

Comparing the clinical and radiological outcomes of pedicular transvertebral screw fixation of the lumbosacral spine in spondylolisthesis versus unilateral transforaminal lumbar interbody fusion (TLIF) with posterior fixation using anterior cages.

STUDY DESIGN: This study retrospectively compares the clinical and radiologic outcomes of unilateral transforaminal lumbar interbody fusion (TLIF) with those of transvertebral screw fixation of the lumbosacral spine in high-grade spondylolisthesis. OBJECTIVE: To examine the outcome and perioperative complications of unilateral TLIF and compare those results with Transvertebral Screw Fixation in the treatment of high-grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: High-grade spondylolisthesis has been associated with a high complication and failure rate regardless of the method of treatment. We compare 2 techniques to improve success rates. METHODS: Forty patients were divided into 2 groups: group A, unilateral TLIF, and group B, transacral screws. The mean age was 33 years (range, 19-48 years), and the mean follow-up was 35 months (range, 24-48 months). The mean grade of spondylolisthesis measured by Meyerding grading was 3.6 (range, 3-5). A Scoliosis Research Society outcome score was obtained on all patients. Fusion was determined by both radiograph and computed tomography scan. RESULTS: Group A: 100% fusion. The slip angle improved from 38.6 degrees (range, 24-78 degrees ) before surgery to 23.8 degrees (range, 12-38 degrees ) after surgery. Group B: 95% of patients evidenced solid fusion by the 6-month follow-up. The slip angle, improved from 38.2 degrees (range, 22-78 degrees ) before surgery to 23 degrees (range, 9-36 degrees ) after surgery. There was no significant improvement in the percentage slip or the sacral inclination in any of the groups. COMPLICATIONS: A: 7 unintended durotomies and 3 wound infections. B: 1 unintended durotomy, 1 pseudarthrosis, 2 wound infections, and 1 implant failure. There were no neurologic complications in any of the groups. The Scoliosis Research Society outcome instrument demonstrated good postoperative pain control, function, self-image, and satisfaction in both groups. CONCLUSION: No significant differences in radiologic and clinical outcome were found, in either group. Both procedures appear to be safe and effective surgically and radiographically.

Using triggered electromyographic threshold in the intercostal muscles to evaluate the accuracy of upper thoracic pedicle screw placement (T3-T6).

STUDY DESIGN: A prospective clinical study of high thoracic pedicle screws monitored with triggered electromyographic (EMG) testing. OBJECTIVE: To evaluate the sensitivity of recording intercostal muscle potentials to assess upper thoracic screw placement. SUMMARY OF BACKGROUND DATA: Triggered EMG testing from rectus muscle recordings, which are innervated from T6 to T12, has identified medially placed thoracic pedicle screws. No clinical study has correlated an identical technique with the intercostal muscle for upper pedicle screws placed in the upper thoracic spine (T3-T6). METHODS: A total of 311 high thoracic screws were placed in 50 consecutive patients. Screws were placed from T3 to T6 and were evaluated using an ascending method of stimulation until a compound muscle action potential was obtained from the intercostal muscles. Screw position was then evaluated using computed tomography and results were compared with evoked EMG threshold values. RESULTS: Fifteen screws (5%) showed penetration on postoperative computed tomography scans. Eleven screws showed medial cortical breakthrough (3.6%), 6 had stimulation thresholds 20 mA. Of the 296 screws with thresholds between 6 and 20 mA, 285 (91%) were within the vertebra. No postoperative neurologic complications were noted in any of the 50 patients. CONCLUSION: In this series, cortical violation is highly unlikely in patients whose stimulation threshold lies between 6 and 20 mA with values 60% to 65% decreased from the mean (98% negative predictive value). Although verification of screw placement should not depend solely on stimulation thresholds, pedicle screw stimulation provides rapid and useful intraoperative information on screw placement during procedures involving the use of thoracic pedicle screws.