Anesthesia machines have been developed by the application of new technology for rapid and easier control of anesthetic concentration. In this study, we used a test lung to investigate whether the time taken to reach the target sevoflurane concentration varies with the rate of fresh gas flow (FGF) and type of anesthesia machine (AM). We measured the times taken to reach the target sevoflurane concentration (2 minimum alveolar concentration = 4%) at variable rates of FGF (0.5, 1, or 3 L/min) and different types of AM (Primus®, Perseus®, and Zeus® [Zeus®-F; Zeus® fresh gas mode, Zeus®-A; Zeus® auto-mode]). Concomitant ventilation was supplied using 100% O2. The AMs were connected to a test lung. A sevoflurane vaporizer setting of 6% was used in Primus®, Perseus®, and Zeus®-F; a target end-tidal setting of 4% was used in Zeus®-A (from a vaporizer setting of 0%). The time taken to reach the target concentration was measured in every group. When the same AM was used (Primus®, Perseus®, or Zeus®-F), the times to target concentration shortened as the FGF rate increased (P < 0.05). Conversely, when the same FGF rate was used, but with different AMs, the time to target concentration was shortest in Perseus®, followed by Primus®, and finally by Zeus®-F (P < 0.05). With regards to both modes of Zeus®, at FGF rates of 0.5 and 1 L/min, the time to target concentration was shorter in Zeus®-A than in Zeus®-F; however, the time was longer in Zeus®-A than in Zeus®-F at FGF rate of 3 L/min (P < 0.05). Shorter times taken to reach the target concentration were associated with high FGF rates, smaller internal volume of the AM, proximity of the fresh gas inlets to patients, absence of a decoupling system, and use of blower-driven ventilators in AM.

Degenerative arthritis of the knee joint has become a major social problem worldwide due to population aging. There are several treatment options for knee osteoarthritis, and the intraarticular injection of sodium hyaluronate is commonly selected by many clinicians as a nonsurgical treatment. However, the efficacy of the treatment is controversial. In this pilot study, we aimed to compare polynucleotide sodium (Conjuran^®) with sodium hyaluronate (Hyruan Plus^®) and 1,4-butanediol diglycidyl ether-crosslinked sodium hyaluronate (Synovian^®) in terms of analgesic efficacy after intraarticular injection in patients with knee osteoarthritis. One of the three intraarticular agents was selected according to what agents were available for outpatients when each patient was enrolled in the study. The 15 enrolled patients were subdivided into 3 groups of 5 patients each. Three injections were performed under ultrasound guidance at a 1-week intervals over a total of 3 weeks. The visual analog scale (VAS) score, the Korean version of the Western Ontario and McMaster Universities Arthritis Index (K-WOMAC), the EuroQol five-dimension scale (EQ-5D) score, and the Korean version of the painDETECT Questionnaire (K-PDQ) score were evaluated before injection and at 1, 2, and 6 weeks after the start of the treatment protocol. The primary endpoint was the change in weight-bearing pain at 4 weeks after the last injection. Secondary endpoints included pain at rest and during walking and the K-WOMAC, EQ-5D, and K-PDQ scores. Weight-bearing pain decreased significantly more from pretreatment to 6 weeks after the start of the treatment protocol in the polynucleotide sodium-treated patients than in the patients who were treated with other agents (p = 0.006, one-way ANOVA). There were no significant between-group differences in the other secondary endpoints. No adverse events occurred. In conclusion, polynucleotide sodium could effectively reduce weight-bearing pain in the patients with knee osteoarthritis compared to standard hyaluronic acid viscosupplementation.

Failed back surgery syndrome (FBSS) is a commonly encountered disease after lumbar surgery. There are many cases where it is difficult to choose a treatment because no specific cause can be found. Nevertheless, according to recent reports, adhesiolysis has shown reasonable evidence. However, considering its poor cost-effectiveness, adhesiolysis cannot be used as the first line of treatment. FBSS patients often suffer from chronic pain; accordingly, they become frustrated when this treatment produces a poor response. Therefore, before the procedure, the target group must be selected carefully. We sought to identify the pre-procedure factors predicting the effect of adhesiolysis in FBSS. A total of 150 patients were evaluated and analyzed retrospectively. Of these 150 patients, 69 were classified as responders three months after the procedure (46%). The outer diameter of the catheter during the procedure and grade of foraminal stenosis were correlated with the procedure effect. In conclusion, of the 2.1 mm diameter of the catheter, 1.7 mm of it was used during the procedure, and the milder the foraminal stenosis, the greater the pain reduction effect was three months after the procedure.

Persistent or recurrent back and leg pain following spinal surgery, known as failed back surgery syndrome (FBSS), significantly limits daily life activities. A lumbar epidural injection can reduce adhesions, inflammation, and nerve compression, although the epidural space can be distorted due to dura mater and epidural tissues changes after spinal surgery. This study analyzed subdural injection during lumbar epidural injection in FBSS patients. We retrospectively analyzed data from 155 patients who received a lumbar interlaminar epidural injection to manage FBSS. We grouped the patients based on the injected contrast medium appearance in the subdural (group S) or epidural spaces (group E) in fluoroscopic contrast images. Demographic, clinical, surgical and fluoroscopic data were recorded and evaluated, as were the pain scores before and after injection. There were 59 patients (38.1%) in the subdural group. Injection distance from the surgery level differed between the groups. Risk of subdural injection at level 1 distance from the surgery level had an odds ratio of 0.374, and at level ≥2, it was 0.172, when compared to level 0. Subdural incidence differed with the distance from surgical site. Physicians should strive to reduce subdural incidence when the injection is planned at surgery site in FBSS.