Regional Anesthesia and Acute Pain Management

There are few options for prolonging the action of amide local anesthetics: an increase in dose and concentration is associated with a higher risk of neurotoxicity and systemic complications, whereas catheter-based techniques are resource-intensive and increase the risk of infection. No new local anesthetic molecules have been introduced since the development of levobupivacaine. Therefore, the use of adjuvants to local anesthetics is considered the most promising approach. A targeted search of publications in Russian and English was conducted in PubMed (MEDLINE) and eLibrary databases using the following keywords and their combinations: блокада периферического нерва / peripheral nerve block, местные анестетики / local anesthetics, адъювант / adjuvant, нейротоксичность / neurotoxicity, дексаметазон / dexamethasone, дексмедетомидин / dexmedetomidine. A total of 66 full-text clinical and experimental studies on perineural and/or systemic use of adjuvants in peripheral nerve and interfascial blocks were included in the analysis. The main groups of adjuvants identified were adrenergic receptor agonists, glucocorticoids, opioids, N-methyl-D-aspartate receptor antagonists magnesium salts, and benzodiazepines. A significant prolongation of sensory block and/or time to first analgesic request was demonstrated. Adverse effects were described, including hemodynamic instability associated with α₂-agonists, hyperglycemia and possible delayed recovery of nerve function with dexamethasone, opioid-induced nausea and vomiting, hypermagnesemia, psychotomimetic effects of ketamine, and midazolam-related neurotoxicity. Particular attention is given to the phenomenon of rebound pain. Perineural and/or systemic administration of dexamethasone and dexmedetomidine, as well as their combination, appears to be the most justified and safe approach to prolonging block duration. However, all adjuvants except epinephrine are used perineurally off-label, which necessitates individualized risk–benefit assessment and further randomized studies, including evaluation of long-term neurotoxicity.

BACKGROUND: Neuropathic pain is one of the most challenging forms of chronic pain and is often refractory to standard pharmacotherapy. Given the limited efficacy of existing therapies, inert gases have attracted interest as potential modulators of nociceptive signaling.

AIM: This work aimed to evaluate the analgesic activity of a krypton-oxygen gas mixture (KrypOx 79) in a preclinical rat model of neuropathic pain.

METHODS: The experiment was conducted in male Wistar rats (n = 40). Neuropathic pain was induced using the chronic constriction injury (CCI) model of the sciatic nerve (Bennett and Xie). Animals were randomly assigned to three groups: krypton–oxygen gas mixture 79 (n = 8), control (air mixture, n = 8), and gabapentin 372 mg/kg (n = 8). Analgesic effects were assessed by changes in mechanical sensitivity thresholds using von Frey filaments (Dixon–Chaplan method) on day 14 after model induction. Statistical analysis was performed using nonparametric tests (Kruskal–Wallis, Friedman test, Dunn post hoc correction).

RESULTS: Rats in the KrypOx 79 group demonstrated a significant 3–4–fold increase in mechanical sensitivity thresholds compared with baseline at 0 and 30 minutes after inhalation (p < 0.05). The analgesic effect gradually declined within 3–4 hours. In the gabapentin group, reduced sensitivity was observed at 3–4 hours after administration, which is consistent with its pharmacokinetic profile.

CONCLUSION: The krypton–oxygen gas mixture (KrypOx 79) produces a pronounced but short-lived analgesic effect in a model of neuropathic pain, with onset within the first 30 minutes after exposure. These findings support the potential of krypton as a fast-acting inhalational analgesic and justify further studies to investigate its mechanisms of action and possible clinical applications.

BACKGROUND: Laparoscopic colorectal surgery is widely used in modern surgical practice and requires optimized anesthetic management. Although the antiemetic effect of propofol-based total intravenous anesthesia (TIVA) is well established, the impact of the anesthesia maintenance technique on postoperative pain, stress response, and gastrointestinal recovery, in the setting of multimodal analgesia with systemic lidocaine infusion, remains less certain and continues to be a subject of debate.

AIM: This study aimed to evaluate the effect of propofol-based total intravenous anesthesia compared with desflurane-based inhalational anesthesia on early postoperative outcomes in patients undergoing laparoscopic colorectal surgery.

METHODS: A single-center cohort study was conducted in patients undergoing elective laparoscopic colon and rectal resections. To improve group comparability, inverse probability of treatment weighting based on propensity scores was applied. A standardized anesthesia and analgesia protocol was used in all cases (including systemic lidocaine infusion); the groups differed only in the maintenance anesthetic technique: desflurane vs. propofol-based total intravenous anesthesia. The primary outcome was postoperative pain intensity assessed using a visual analog scale (VAS) over 48 hours, as well as cumulative pain intensity expressed as the area under the pain curve (AUC VAS 0–48 h, VAS·h). Secondary outcomes included postoperative nausea and vomiting, analgesic requirements, markers of surgical stress response, recovery of gastrointestinal function, hemodynamic stability, and safety.

RESULTS: The effective sample size after weighting was 91.9 patients. The main effect of anesthetic technique on pain intensity over time in the repeated-measures model did not reach statistical significance; however, cumulative pain intensity was significantly lower in the TIVA group compared with the desflurane group (AUC difference −14.2 VAS·h; 95% CI −25.7 to −2.6; p = 0.016).

Total intravenous anesthesia was associated with a significant reduction in the incidence of postoperative nausea and vomiting (relative risk 0.32; 95% CI 0.14–0.73; p = 0.007) and a clinically relevant trend toward reduced postoperative opioid analgesic requirements. No differences were observed between groups in endocrine–metabolic stress response, gastrointestinal recovery, intraoperative hypotension, or overall safety profile.

CONCLUSION: These findings support the inclusion of propofol-based total intravenous anesthesia in enhanced recovery protocols and highlight the need for further studies to assess long-term outcomes.

BACKGROUND: Low back pain in is one of the most common causes of disability and seeking medical help. Epidural steroid injection can be used when other conservative methods do not help. Epidural corticosteroid injection itself is a conservative method of steroid administration, with or without local anesthetics, directly into the epidural space using various approaches such as interlaminar and transforaminal. The mechanism of action of epidural glucocorticoid administration is mainly anti-inflammatory and anti-edematous. Currently in Russia, no glucocorticoid has epidural administration listed among its clinical indications.

AIM: This trial aimed to compare the efficacy of transforaminal epidural administration of particulate versus non-particulate glucocorticoids in the treatment of radicular pain in the lumbosacral region.

METHODS: The trial included 40 patients who were randomized into 2 groups using the lottery method. The first group (n = 20) received transforminal epidural blocks with non-particulate steroids; the second group (n = 20) received transforminal epidural blocks with particulate steroids. Pain level was assessed using a numerical rating scale, and the Oswestry Disability Index (ODI) was calculated. Normality of data distribution was tested using the Shapiro–Wilk test; differences between groups in quantitative and rank variables were assessed using the Mann–Whitney U test. Microsoft Excel and IBM SPSS Statistics were used for data analysis. Differences were considered significant at p < 0.05.

RESULTS: When comparing the two groups, the pain level on the numerical rating scale in the triamcinolone group decreased over 3 months from 7.5 [7, 8] to 1 [1, 5] points, whereas in the dexamethasone group, pain decreased immediately after treatment from 7 [7, 8] to 1 [1, 1] points, but after 3 months, pain persisted at 4 [1, 6] points. This shows a trend in favor of triamcinolone in the medium term. When comparing the two groups by ODI, a significant reduction in the impact of pain on daily life was observed in both groups.

CONCLUSION: This comparative analysis of the analgesic effect of epidural particulate versus non-particulate steroids revealed a trend toward greater efficacy of epidural particulate glucocorticoids.

BACKGROUND: Spinal hematoma is one of the most serious complications of neuraxial anesthesia and may result in decreased quality of life, severe disability, or even death. Although the incidence of this complication is low, it may increase remarkably in the presence of certain risk factors. Therefore, when planning neuraxial techniques, particularly as an adjunct to general endotracheal anesthesia, the risk–benefit ratio should be carefully considered.

CASE DESCRIPTION: A 44-year-old female patient was admitted for surgical treatment of a hemangioma of the right hepatic lobe. The procedure was performed under combined general and epidural anesthesia. Thirty-four hours after surgery, the patient developed severe pain at the surgical site. On postoperative day 2, numbness in the lower extremities was noted, and the epidural catheter was removed. On postoperative day 5, pain developed at the site of the previously placed epidural catheter. Subsequent evaluation revealed an intradural hematoma at the same level. Due to the progression of neurological symptoms, surgical intervention was performed, including spinal cord decompression and evacuation of the hematoma. Following this procedure, spinal cord compression and neurological deficits persisted, necessitating a second neurosurgical intervention, including evacuation of an intermuscular hematoma in the postoperative wound and revision of the subdural space. On postoperative day 10, the patient was transferred to a rehabilitation unit and was subsequently discharged without neurological deficits.

CONCLUSION: This case demonstrates that clinical manifestations of spinal hematoma may occur at any stage of hospitalization: immediately after epidural catheter placement, during catheterization, or even several days after catheter removal. Accordingly, careful postoperative monitoring is essential in patients receiving epidural anesthesia. Since favorable outcomes after spinal cord decompression are critically dependent on the time between the onset of severe neurological symptoms and surgical intervention, early magnetic resonance imaging of the spine is recommended at the slightest suspicion of spinal hematoma. If magnetic resonance imaging is not readily available, alternative neuroimaging modalities should be performed without delay.