Design of an Optical Transparent Absorber and Defect Diagnostics Analysis Based on Near-Field Measurement.

To reduce the electromagnetic wave interference caused by cavity resonance or electromagnetic wave leakage, herein, an optical transparent radar absorbing structure (RAS) was designed using transparent conductive oxides (TCOs) with a high optical transmittance and electrical conductivity, and a procedure was proposed for detecting possible defects in the fabrication and operation and for assessing the influence of the defects on the electromagnetic performance. To detect locally occurring defects in planar and three-dimensional absorbing structures, a measurement system based on an open-ended near-field antenna capable of producing small beam spots at a close distance was constructed. Moreover, the reflection characteristics of the transparent RAS were derived from a simplified multiple reflection equation, and the derived results were compared with the analysis results of an equivalent circuit model to predict the surface resistance of the TCO coating layer, based on which the presence of defects could be confirmed. By using the experimental results, the predicted surface resistance results of the coating layer and the results measured using a non-contact sheet resistance meter were compared and were found to correspond, thereby confirming the effectiveness of the proposed defect detection method.

Range of S-100ß levels during functional endoscopic sinus surgery with moderately controlled hypotension.

The aim of this study is to determine the range of S-100ß levels during functional endoscopic sinus surgery (FESS) when the mean arterial pressure (MAP) was controlled within 60-70 mmHg. After anesthesia induction with propofol and remifentanil, the patient was positioned in the reverse Trendelenburg position and MAP was controlled within 60-70 mmHg during surgery. For the S-100ß assay, blood was taken from a radial arterial catheter before (baseline) and at 20 (T 20) and 60 (T 60) min after setting the reverse Trendelenburg position and controlled hypotension, and at 60 (T post60) min after the end of the operation. In total, 34 patients completed the study. Baseline S-100ß was 0.00837 ± 0.00785 ng/mL. The levels at T 20 and T 60 were 0.02057 ± 0.01739 and 0.01987 ± 0.01145 ng/mL, respectively. The level of T post60 was 0.05436 ± 0.02318 ng/mL. The level at T 20 increased significantly versus the baseline level (P < 0.001); there were no significant differences between T 20 and T 60. The level at T post60 was significantly different versus T 20 and T 60 (P < 0.001). However, all S-100ß levels were within the normal range. S-100ß-a sensitive biomarker of cerebral ischemia-was within the normal range during FESS when moderate hypotension (MAP >60 mmHg) was provided. Thus, moderate hypotension would be seemed to be a safe and effective anesthetic technique for FESS without risk for cerebral ischemia.

Effectiveness of Epidural Balloon Neuroplasty in Patients With Chronic Spinal Stenosis Accompanied by Redundant Nerve Roots: A Longitudinal Cohort Study.

BACKGROUND: Symptomatic patients with chronic lumbar spinal stenosis (LSS) accompanied by redundant nerve roots (RNR) have poor treatment outcomes. Recently, epidural balloon neuroplasty has been shown to be effective in patients with chronic LSS. OBJECTIVE: To evaluate the effectiveness of epidural balloon neuroplasty in patients with chronic LSS accompanied by RNR. STUDY DESIGN: Retrospective cohort study. SETTING: A single pain clinic of a tertiary medical center in Seoul, Republic of Korea. METHODS: Patients with chronic LSS were divided into groups with (RNR group) and without RNR (non-RNR group). The generalized estimating equations (GEE) model was used to evaluate the effectiveness of epidural balloon neuroplasty in both groups based on Numeric Rating Scale (NRS-11) score for pain intensity, Medication Quantification Scale III (MQS III), and proportion of functional improvement at one, 3, and 6 months postprocedure. RESULTS: GEE analyses showed a significant reduction of pain intensity in NRS-11 and functional improvement compared to baseline throughout the 6-month follow-up period in both groups (P < 0.001), without differences between groups. After adjusting for potential confounding variables, the NRS-11 of leg pain one month after the procedure in the RNR group was reduced less than that in the non-RNR group (P = 0.016), although we did not find a significant time and group interaction. After adjustment, less functional improvement was observed 3 months after the procedures in the RNR group than in the non-RNR group (P = 0.001), with a significant interaction between time and group (P = 0.003). The estimated mean MQS III values were unchanged at 6 months regardless of adjustment in both groups. LIMITATIONS: Retrospective design and a lack of information on adjuvant nonpharmacologic therapies. CONCLUSION: Epidural balloon neuroplasty may be an effective option for reducing pain in patients with chronic LSS accompanied by RNR.

Comparison of sitting and prone positions for real-time ultrasound-guided thoracic epidural catheter placement: a randomized controlled trial.

INTRODUCTION: Real-time ultrasound-guided thoracic epidural catheter placement (US-TECP) has been recently introduced. Patient's position is associated with the success of spine interventions; however, the effects of position on the outcome of the procedure remain unknown. We aimed to assess the clinical usefulness of patient positioning during real-time US-TECP. METHODS: Patients were randomly assigned to the prone position group (group P) and sitting position group (group S). The primary outcome was needling time during the procedure. The secondary outcomes were time to mark space, total number of needle passes, number of skin punctures, first-pass success, final success, crossover success, and visibility of ultrasound (US) views. Global Rating Scale (GRS) score, Patient Comfort Scale score, procedural pain intensity, patient satisfaction, and procedure-related complications were also determined. RESULTS: Sixty-four patients were included in this study. The needling time was significantly shorter in group P than in group S (36.5 (26.5-51.0) vs 59.5 (34.5-152.0) s, p<0.01). The numbers of needle passes and skin punctures were significantly lesser in group P than in group S. First-pass success was higher in group P than in group S. Group P had higher GRS compared with group S. The time to mark space, final success, US visibility score, Patient Comfort Scale score, procedural pain intensity, and patient satisfaction did not differ between the groups. One patient in group S developed a vasovagal reaction. DISCUSSION: This study shows that prone position may be preferred for real-time US-TECP, considering its better clinical usefulness. TRIAL REGISTRATION NUMBER: KCT0005757.

Comparison of the acoustic windows for the thoracic paramedian epidural approach after shoulder rotation: The lateral decubitus versus the sitting position.

BACKGROUND: The aim of this study was to compare the mean lengths of the posterior longitudinal ligament (PLL) as the acoustic window during the thoracic paramedian epidural approach after shoulder rotation, while subjects were in the lateral decubitus or in the sitting position. METHODS: Thirty-two adult male volunteers were placed in the right decubitus position or sitting position on a horizontal operating table. To obtain an optimal ultrasound view for the PLL on the right side, thoracic spinal ultrasonography was performed at the T6/7 interspace using the paramedian oblique sagittal plane. PLL length was measured on the ultrasound image before and after right shoulder rotation. RESULTS: Before shoulder rotation, the difference in mean PLL length between the sitting (11.1±1.3mm) and lateral decubitus (10.7±1.2mm) positions was not statistically significant (P=0.05). Within-position, the before and after comparison revealed that after shoulder rotation, PLL length was significantly increased to 12.2±1.4mm (P<0.001) and 12.0±1.5mm (P<0.001) in the sitting and lateral decubitus positions, respectively. However, after shoulder rotation the between-position difference in mean PLL length was not statistically significant (P=0.50) CONCLUSIONS: Shoulder rotation did not result in a statistically significant difference in the dimension of the acoustic target window for paramedian thoracic epidural access in the sitting compared to the lateral decubitus position.