Therapeutic management of chronic neuropathic pain: An examination of pharmacologic treatment

Neuropathic pain is defined as pain caused by a lesion in the nervous system and is common in clinical practice. Diagnosis can be difficult. Recommendations for first-line pharmacologic treatments are based on positive results from multiple, randomized, controlled trials, and recommendations for second-line pharmacologic treatments are based on the positive result of a single, randomized, controlled trial or inconsistent results of multiple, randomized, controlled trials. The results of published trials and clinical experience provide the foundation for specific recommendations for first-line treatments, which include gabapentin, 5% lidocaine patch, opioid analgesics, tramadol hydrochloride, and tricyclic antidepressants (TCAs). Gabapentin (up to 3,600 mg/day) significantly reduced pain compared with placebo; improvements in sleep, mood, and quality of life were also demonstrated. Adverse effects of gababentin include somnolence and dizziness, and, less commonly, gastrointestinal symptoms and mild peripheral edema. Thus, monitoring and dosage adjustment are required, without discontinuation of the drug. Gabapentin combined with morphine achieved better analgesia at lower doses of each drug than each drug alone, with only mild adverse effects. The first medication that proved effective for neuropathic pain in placebo-controlled trials was TCAs. Treatment decisions for patients with neuropathic pain can be difficult. Interest in the mechanisms and treatment of chronic neuropathic pain has increased during the past years, resulting in significant treatment advances in the future. In this article all recent knowledge on therapeutic management of chronic neuropathic pain is presented. © 2006 New York Academy of Sciences

Prediction of the distance from the skin to the lumbar epidural space in the Greek population, using mathematical Models

Background and Objectives: The skin to lumbar epidural space distance (SLED) is variable, and therefore the ability to clinically predict the SLED may help increase the success of epidural anesthesia/analgesia. The goal of this study was to determine the relationship between the SLED and demographic/anthropometric variables in the Greek population, and develop a mathematical model for its prediction. Methods: This prospective randomized study enrolled 406 male and female Greek patients who required an epidural block as part of their anesthetic management. With patients placed in the left lateral and knee-chest position, the lumbar epidural space was located by the loss of resistance to normal saline technique. Statistical analysis was used to identify the relationship between SLED, and the following variables were evaluated: age, weight, height, body mass index, body surface area, intervertebral space used, pregnancy, and geographic origin within Greece. Results: No adverse events or dural punctures occurred. Mean SLED in the general population was 4.98 ± 0.95 cm, with values significantly higher in males (5.37 ± 0.88 cm) compared with females (4.83 ± 0.93 cm). SLED was best associated with weight, body surface area, and body mass index. Mathematical formulae for prediction of SLED in the general population and the female population were derived from linear regression analysis. These formulae were able to predict approximately half of the observed variability in SLED. Conclusions: While mathematical models of SLED can be a useful tool, they should not be exclusively relied on in the clinical setting, but rather should be used as an adjunct to standardized techniques to improve the safety and efficacy of epidural anesthesia/analgesia. © 2005 World Institute of Pain

Pregabalin vs. Opioids for the treatment of neuropathic cancer pain: A prospective, head-to-head, randomized, open-label study

Objectives: Neuropathic cancer pain (NCP) is a common manifestation of cancer and/or its treatment. Treatment following the WHO analgesic ladder provides relief for the majority of cancer pain patients; however, concern remains that opioids may be less efficacious for neuropathic pain (NP) compared with nociceptive pain, often necessitating the use of higher doses. Adjuvants, such as pregabalin, have shown to be efficacious for the treatment of NP, although data come mostly from noncancer studies. The comparative efficacy and safety of opioids versus adjuvants has not been studied for NCP. The aim of this study was to directly compare pregabalin versus a strong opioid for the treatment of NCP. Methods: A total of 120 patients, diagnosed with "definite" NCP, were randomized into two groups and received increasing doses of either oral pregabalin or transdermal fentanyl for 28 days. VAS score, patient satisfaction, need for opioid rescue, and adverse events (AEs) were recorded. Results: In the pregabalin group, a significantly higher proportion of patients achieved at least 30% reduction in VAS compared with the fentanyl group (73.3%, 95% CI: 60.3%-83.93 vs. 36.7%, 95% CI: 24.5%-50.1%, P < 0.0001, respectively), while the percentage mean change from baseline was also significantly different [46% (95% CI: 39.5%-52.8%) for pregabalin and 22% (95% CI: 14.9%-29.5%) for fentanyl (P < 0.0001)]. Patient-reported satisfaction was more frequent with pregabalin, while AEs and treatment discontinuations were more frequent in the fentanyl group. Discussion: Prompt use of a neuropathic pain-specific adjuvant, such as pregabalin, in NCP may lead to better control of the neuropathic component, with opioid-sparing effects. © 2013 World Institute of Pain

The effect of transversus abdominis plane block on acute and chronic pain after inguinal hernia repair. A randomized controlled trial

Background: This prospective double-blind randomized study aimed at evaluating the short- and long-term postoperative analgesic efficacy of the ultrasound-guided tranversus abdominis plane (TAP) block in inguinal hernia repair under general anesthesia. Methods: Sixty patients undergoing inguinal hernia repair were allocated to TAP block with either ropivacaine 0.75% 20 mL or placebo 20 mL. Postoperatively, they had access to a patient-controlled analgesia (PCA) device administering 1 mg doses of morphine as rescue analgesia. Pain was assessed at rest and during movement with the numeric rating scale (NRS) score 3,6 and 24 hs postoperatively. Other variables recorded were intraoperative dose of remifentanil required to maintain systolic arterial pressure within 20% of baseline, mg of morphine used in the Post Anesthesia Care Unit (PACU) and total dose of morphine administered via the PCA device. Six months after surgery, the occurrence of chronic pain was assessed with the NRS score at rest and during movement. Patients were also asked to fill in the DN4 questionnaire to estimate the development of neuropathic pain. Results: Patients who were administered ropivacaine demonstrated significantly less pain at rest and on movement, as expressed by NRS scores in comparison to patients in the placebo group. The former group also required less remifentanil intraoperatively, less morphine during the PACU stay and had lower morphine consumption through the PCA device. Six months after surgery, pain scores at rest and during movement were comparable between the two groups. At the same time DN4 scores were low and comparable between the two groups. Conclusion: Ultrasound-guided TAP block provided better pain control than placebo in the acute setting after inguinal hernia repair. However, the incidence of chronic pain was low and not significantly affected by the performance of the block. © 2019 IJS Publishing Group Lt

Difficult intubation provokes bacteremia

Purpose: To evaluate the prevalence of bacteremia after mask ventilation, laryngoscopy, and endotracheal intubation before induction of general anesthesia and to discover any correlation between traumatic manipulations and bacteremia. The specific bacteria responsible, knowledge of which may guide the prophylactic use of antibiotics, also were investigated. Methods: Fifty patients were enrolled. Three 10-mL blood samples were collected from a peripheral vein 10 min before induction of anesthesia, 10 min after mask ventilation, and 10 min after intubation. All samples were placed in aerobic and anaerobic bottles for culture and bacterial identification. Results: Cultures received 10 min after intubation were positive in 12% of patients. The following strains were isolated: Escherichia coli in two cases, Staphylococcus aureus in three cases, and Peptostreptococcus anaerobius in one case. A strong positive correlation was found between difficult intubation and bacteremia. No correlation between bacteremia and easy intubation or between bacteremia and face mask ventilation was identified. Conclusion: Traumatic manipulations during difficult laryngoscopy and endotracheal intubation could cause bacteremia. This finding may justify and guide prophylactic use of antibiotics. © 2008 Mary Ann Liebert, Inc