Perineural adjuncts for peripheral nerve block

Combined Dexamethasone and Dexmedetomidine as Adjuncts to Popliteal and Saphenous Nerve Blocks in Patients Undergoing Surgery of the Foot or Ankle: A Randomized, Blinded, Placebo-controlled Clinical Trial

BACKGROUND

Both dexamethasone and dexmedetomidine increase the duration of analgesia of peripheral nerve blocks. The authors hypothesized that combined intravenous dexamethasone and intravenous dexmedetomidine would result in a greater duration of analgesia when compared with intravenous dexamethasone alone and placebo.

METHODS

The authors randomly allocated participants undergoing surgery of the foot or ankle under general anesthesia and with a combined popliteal (sciatic) and saphenous nerve block to a combination of 12 mg dexamethasone and 1 µg/kg dexmedetomidine, 12 mg dexamethasone, or placebo (saline). The primary outcome was the duration of analgesia measured as the time from block performance until the first sensation of pain in the surgical area as reported by the participant. The authors predefined a 33% difference in the duration of analgesia as clinically relevant.

RESULTS

A total of 120 participants from two centers were randomized and 119 analyzed for the primary outcome. The median [interquartile range] duration of analgesia was 1,572 min [1,259 to 1,715] with combined dexamethasone and dexmedetomidine, 1,400 min [1,133 to 1,750] with dexamethasone alone, and 870 min [748 to 1,138] with placebo. Compared with placebo, the duration was greater with combined dexamethasone and dexmedetomidine (difference, 564 min; 98.33% CI, 301 to 794; P < 0.001) and with dexamethasone (difference, 489 min; 98.33% CI, 265 to 706; P < 0.001). The prolongations exceeded the authors' predefined clinically relevant difference. The duration was similar when combined dexamethasone and dexmedetomidine was compared with dexamethasone alone (difference, 61 min; 98.33% CI, -222 to 331; P = 0.614).

CONCLUSIONS

Dexamethasone with or without dexmedetomidine increased the duration of analgesia in patients undergoing surgery of the foot or ankle with a popliteal (sciatic) and saphenous nerve block. Combined dexamethasone and dexmedetomidine did not increase the duration of analgesia when compared with dexamethasone.

EDITOR’S PERSPECTIVE

Dexamethasone versus Dexmedetomidine as Adjuvants in Ultrasound Popliteal Sciatic Nerve Block for Hallux Valgus Surgery: A Mono-Centric Retrospective Comparative Study

Background and Aim

Ultrasound popliteal sciatic nerve block (UPSNB) is commonly performed in foot and ankle surgery. This study aims to assess the use of dexmedetomidine and dexamethasone as adjuvants in UPSNB for hallux valgus (HV) surgery, comparing their efficacy in producing motor and sensory block and controlling postoperative pain. The adverse event rate was also evaluated.

Methods

This mono-centric retrospective study included 62 adult patients undergoing HV surgery: 30 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg and dexamethasone 4 mg (Group 1), whereas 32 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg, and dexmedetomidine 1 mcg/Kg (Group 2). At first, the visual analogue scale (VAS) was evaluated after 48 hours. The other outcomes were time to motor block regression, evaluation of the first analgesic drug intake, analgesic effect, adverse effects (hemodynamic disorders, postoperative nausea and vomiting (PONV)) and patient satisfaction. The continuous data were analyzed with student's t-test and the continuous one with χ2. Statistical significance was set at a p-value lower than 0.05.

Results

No significant difference was found in VAS after 48 hours (4.5 ± 1.6 vs 4.7 ± 1.7, p = 0.621) to motor block regression (18.9 ± 6.0 vs 18.7 ± 6, p = 0.922). The number of patients that took their first analgesic drug in the first 48 h (p = 0.947 at 6 hours; p = 0.421 at 12 hours; p = 0.122 at 24 hours and p = 0.333 at 48 hours) were not significant. A low and similar incidence of intraoperative hemodynamic disorders was recorded in both groups (hypotension p = 0.593; bradycardia p = 0.881). Neither PONV nor other complication was found. Patients in Group 1 reported a lower degree of interference with sleep (p = 0.001), less interference with daily activities (P = 0.002) and with the affective sphere (P = 0.015) along with a more satisfactory postoperative pain management (p < 0.001) as compared to Group 2.

Conclusion

No significant differences were observed in the duration of motor and sensory blockade between patients in both groups. Additionally, both groups showed good pain control with a low rate of adverse effects, even if there was no clinical difference between the groups. However, patients who received dexamethasone reported experiencing less interference with their sleep, daily activities and overall emotional well-being, and overall pain control.

Ultrasound-guided erector spinae nerve block for relief of endometriosis pain in the emergency department

Endometriosis is a debilitating chronic condition often accompanied by severe pelvic pain and infertility issues. When outpatient medical management is not adequate, controlling pain can be challenging for providers in the acute setting. We report the case of a 23-year-old female with a past medical history of endometriosis who presented to a freestanding emergency department with a chief complaint of 10/10 pelvic pain on a numeric rating scale. She had tried non-steroidal inflammatory medications and heat with no success. The patient had medication intolerances to opioid analgesics and was given ketorolac intramuscularly with no relief of her pain. The emergency physician discussed and offered to perform an erector spinae plane nerve block (ESPB) for pain relief. Ultrasonography was utilized for visualization of landmarks with a curvilinear transducer; a 20-gauge Pajunk® Sonoplex needle was used to inject a total of 100 mg bupivacaine 0.25% without epinephrine along with dexamethasone 10 mg under the bilateral erector spinae fascial planes at the T9 level. Post-procedure, the patient had significant improvement in pain and rated it a 2/10. Utilizing nerve blocks for endometriosis and other chronic pelvic pain in the acute care setting can serve as an effective alternative to opioids. In patients with multiple medication intolerances and for providers navigating pain control in the setting of a nationwide opioid crisis, ESPB blocks can help alleviate acute pain or exacerbations of chronic pain. This case demonstrates the first known use of an ESPB to relieve endometriosis pain in the emergency department.

Local anaesthetic adjuncts for peripheral nerve blockade

PURPOSE OF REVIEW

Moderate-to-severe pain is common and remains a significant problem. Compared with opioid analgesia alone, single-shot peripheral nerve blockade has been associated with improved pain relief and the potential of decreased side effects. Single-shot nerve blockade, however, is limited by its relatively short duration of action. In this review, we aim to summarize the evidence related to local anaesthetic adjuncts for peripheral nerve blockade.

RECENT FINDINGS

Dexamethasone and dexmedetomidine exhibit characteristics that most closely resemble the ideal local anaesthetic adjunct. In upper limb block, dexamethasone has been demonstrated to be superior to dexmedetomidine regardless of administration route for the duration of sensory and motor blockade as well as the duration of analgesia. No clinically significant differences between intravenous and perineural dexamethasone were found. Perineural and intravenous dexamethasone have the potential to prolong sensory blockade to a greater extent than motor blockade. The evidence indicates that the mechanism of action of perineural dexamethasone in upper limb block is systemic in nature. Unlike perineural dexmedetomidine, intravenous dexmedetomidine has not been shown to result in differences in the characteristics of regional blockade compared with local anaesthetic alone.

SUMMARY

Intravenous dexamethasone is the local anaesthetic adjunct of choice, increasing the duration of sensory and motor blockade as well as the duration of analgesia by 477, 289 and 478 min, respectively. In view of this, we recommend consideration of the intravenous administration of dexamethasone at a dose of 0.1-0.2 mg/kg for all patients undergoing surgery whatever the level of postoperative pain, mild, moderate or severe. Further research should focus on the potential synergism of action between intravenous dexamethasone and perineural dexmedetomidine.

Regional anaesthesia for ambulatory surgery

Regional anaesthesia (RA) has an important and ever-expanding role in ambulatory surgery. Specific practices vary depending on the preferences and resources of the anaesthesia team and hospital setting. It is used for various purposes, including as primary anaesthetic technique for surgery but also as postoperative analgesic modality. The limited duration of action of currently available local anaesthetics limits their application in postoperative pain control and enhanced recovery. The search for the holy grail of regional anaesthetics continues. Current evidence suggests that a peripheral nerve block performed with long-acting local anaesthetics in combination with intravenous or perineural dexamethasone gives the longest and most optimal sensory block. In this review, we outline some possible blocks for ambulatory surgery and additives to perform RA. Moreover, we give an update on local anaesthesia drugs and adjuvants, paediatric RA in ambulatory care and discuss the impact of RA by COVID-19.

Effects of Novel Multimodal Transversus Abdominis Plane Block on Postoperative Opioid Usage and Hospital Length of Stay Following Elective Ventral Hernia Repair

Background and objective Traditional transversus abdominis plane (TAP) blocks consisting of a local anesthetic, typically bupivacaine, have previously been shown to reduce postoperative pain following gastrointestinal surgery, including hernia repair. However, elective abdominal wall reconstructions for the repair of large ventral hernias continue to cause patients significant postoperative pain, resulting in prolonged hospital stays and need for opioid pain medication. This study aimed to analyze the postoperative opioid pain medication usage and hospital length of stay (LOS) in patients who received a nontraditional multimodal TAP block of ropivacaine (local anesthetic), ketorolac (non-steroidal anti-inflammatory), and epinephrine following elective ventral hernia repair. Methods A retrospective review of medical records for patients who underwent elective robotic ventral hernia repair by a single surgeon was conducted. Postoperative hospital LOS and opioid usage for patients with the multimodal TAP block were compared to those without. Results A total of 334 patients met the inclusion criteria for LOS analysis: 235 received the TAP block and 109 did not. Patients who received the TAP block had a statistically significant shorter LOS compared to patients who had no TAP block (1.09 ± 1.22 days vs. 2.53 ± 1.57 days; P<0.001). Medical records for 281 patients, 214 with the TAP block and 67 without the TAP block, contained information and were analyzed for postoperative opioid usage. A statistically significantly fewer number of patients who had the TAP block required hydromorphone patient-controlled analgesia pump (3.3% vs. 36%; P<0.001) and oral opioids (29% vs. 78%; P<0.001) postoperatively. Those with TAP block required intravenous opioids more frequently (50% vs 10%; P<0.001) although at much less dosages than those without TAP block (4.86 ± 2.62 mg vs. 10.29 ±3.90 mg; P<0.001). Conclusion In conclusion, this multimodal TAP block of ropivacaine, ketorolac, and epinephrine may represents an effective method to improve hospital LOS and postoperative opioid usage in patients undergoing robotic abdominal wall reconstruction for ventral hernia repair.

Liposomal Bupivacaine in Dentistry and Oral and Maxillofacial Surgery. A Review of Human and Veterinary Literature

This article reviews the human and veterinary literature regarding liposome encapsulated bupivacaine use in dentistry and oral and maxillofacial surgery. The purpose of this review is to present available information on this local anesthetic in a manner that will allow veterinary dentists and oral and maxillofacial surgeons to use evidence-based information when considering incorporating liposomal bupivacaine into their practice. The twelve human clinical studies and three veterinary reports that met the literature search criteria do not support the use of liposomal bupivacaine in veterinary dentistry and oral and maxillofacial surgery.

Effect of Intramuscular Tramadol on the Duration of Clinically Relevant Sciatic Nerve Blockade in Patients Undergoing Calcaneal Fracture Fixation: A Randomized Controlled Trial

BACKGROUND

Calcaneal fracture fixation can generate severe postoperative pain and analgesia can be supported by a sciatic nerve block. However, following resolution of the sensory blockade, rebound pain may ensue. The aim of this study was to assess whether an incidental finding of two patients with an extension of the sciatic nerve block beyond 24 h following 100 mg of intramuscular tramadol administration could be confirmed.

METHODS

Thirty-seven patients scheduled for a calcaneal intramedullary fixation (Calcanail^®) were randomly divided into two groups. The tramadol group (n = 19) received a sciatic nerve block with 20 mL of 0.25% bupivacaine and a concomitant dose of 100 mg of intramuscular tramadol, while the control group (n = 18) received an identical sciatic nerve block with concomitant injection of normal saline (placebo). All patients had a spinal anesthesia with light sedation for the procedure. The time to first analgesic request defined as appearance of any pain (NRS > 0) was assessed as the primary endpoint with a clinically relevant expected result of at least 50% elongation in sensory blockade.

RESULTS

The median time to first analgesic request from time of blockade in the tramadol group was 670 min compared with 578 min in the control group. The result was clinically not relevant and statistically not significant (p = 0.17). No statistical difference could be demonstrated in the time to first opioid request, although a trend for opioid sparing in the tramadol group could be seen. Total morphine consumption in the first 24 h was also statistically insignificant (the tramadol group 0.066 mg kg^-1 compared with 0.125 mg kg^-1 in the control group). In conclusion, intramuscular tramadol does not extend the duration of analgesia of a sciatic nerve block following a calcaneal fracture fixation beyond 2 h and an opioid sparing effect could not be demonstrated in this trial.

Comparing Effect of Adding Ketamine versus Dexmedetomidine to Bupivacaine in Pecs-ⅠⅠ Block on Postoperative Pain Control in Patients Undergoing Breast Surgery

BACKGROUND

Pecs-II block has previously and successfully demonstrated a good quality of perioperative analgesia for breast surgery.

OBJECTIVE

This study aimed to compare the quality of postoperative pain control when adding either ketamine or dexmedetomidine to bupivacaine 0.25% for Pecs-II block.

METHODS

This prospective randomized double-blind study was conducted on 159 female patients with American society of anesthesiologist (ASA) physical status class I-III scheduled to have modified radical mastectomy. Patients were randomly assigned into three groups. Each group included 53patients to receive ultrasound guided Pecs-II blocks with either 32 mL of 0.25% bupivacaine added to ketamine hydrochloride 1 mg/kg (BK group), 32 mL of 0.25%bupivacaine added to dexmedetomidine 1 ug/kg (BD group) or 32 mL of 0.25% bupivacaine only (B group).The primary outcome of this study was the total postoperative morphine consumption for the first 24 hours postoperatively. The time of the first request of analgesia, the pain scores at rest of ipsilateral arm, and the intra-operative fentanyl requirements, were the secondary outcome measures. Any side effects occurred were recorded.

RESULTS

The total postoperative morphine consumption was significantly lower in patients received bupivacaine with addition of either ketamine (BK group), (10.3±2.6 mg), or dexmedetomidine (BD group), (3.8±0.2 mg) respectively, versus patients received only bupivacaine (B group), (16.9±5.3 mg). Both ketamine (BK group) and dexmedetomidine (BD group) added to bupivacaine significantly prolonged the time to first analgesic request (16.7±4.5 h), (21.6±1.6 h) in both groups respectively compared to patients received bupivacaine alone (B group), (11.5±1.2 h).The pain score was variable between the three groups over different times during the first 24 hours postoperatively. There was no significant difference in perioperative hemodynamics, O2 saturation, sedation scores or side effects observed between the three groups. Patient satisfaction was reported to be the best in patients received dexmedetomidine added to bupivacaine than the other patients who received ketamine as an additive or those who received bupivacaine alone.

CONCLUSION

Adding dexmedetomidine to bupivacaine provides more effective postoperative pain control than adding ketamine during Pecs-II blocks for breast cancer surgery.

Adjuvant Drugs for Peripheral Nerve Blocks: The Role of Alpha-2 Agonists, Dexamethasone, Midazolam, and Non-steroidal Anti-inflammatory Drugs

Adjuvant drugs for peripheral nerve blocks are a promising solution to acute postoperative pain and the transition to chronic pain treatment. Peripheral nerve blocks (PNB) are used in the brachial plexus, lumbar plexus, femoral nerve, sciatic nerve, and many other anatomic locations for site-specific pain relief. However, the duration of action of a PNB is limited without an adjuvant drug. The use of non-opioid adjuvant drugs for single-shot peripheral nerve blocks (sPNB), such as alpha-2 agonists, dexamethasone, midazolam, and non-steroidal anti-inflammatory drugs, can extend the duration of local anesthetics and reduce the dose-dependent adverse effects of local anesthetics. Tramadol is a weak opioid that acts as a central analgesic. It can block voltage-dependent sodium and potassium channels, cause serotonin release, and inhibit norepinephrine reuptake and can also be used as an adjuvant in PNBs. However, tramadol's effectiveness and safety as an adjuvant to local anesthetic for PNB are inconsistent. The effects of the adjuvants on neurotoxicity must be further evaluated with further studies to delineate the safety in their use in PNB. Further research needs to be done. However, the use of adjuvants in PNB can be a way to help control postoperative pain.

Ultrasound-Guided Transversus Abdominis Plane Block in Shetland Ponies: A Description of a Three-Point Injection Technique and Evaluation of Potential Analgesic Effects

Colic surgery is one of the most painful procedures carried out in horses. Common strategies to alleviate immediate postsurgical abdominal pain include the administration of potent systemic analgesics; however, these may cause unwanted adverse effects such as cardiovascular depression, ileus, and ataxia. The administration of local anesthetics at the incision site in form of an ultrasound-guided subcostal transversus abdominis plane (TAP) block may therefore be preferred to provide adequate analgesia without significant side effects. To date, no technique for a TAP block in horses undergoing median celiotomy has been described. The objective of the study was to develop a TAP block technique, which will lead to the desensitization of the ventrolateral abdominal wall and adjacent skin area of experimental Shetland Ponies using bupivacaine 0.125%. This is a prospective, blinded, self-controlled trial. A cadaver study was performed to determine the ideal injection points and the volume required to stain the nerves responsible for the sensation of the ventrolateral abdominal wall and skin in Shetland pony cadavers (i.e., T9-L 2). Subsequently, using the ideal injectate volume and the landmarks obtained in the first phase of the study, six Shetland ponies received a bilateral TAP injection, either with a local anesthetic solution (bupivacaine 0.125%) or with saline in a randomized, crossover, blinded fashion. Effectiveness was determined over a 4 hour postinjection time, by using a pinprick technique. Significant differences were found to the responses of the pinprick evaluation between the bupivacaine- and saline-treated sides after 30 minutes of TAP block injection. Reported "learned behavior" could have affected the results of the pinprick testing. The TAP block technique reported in this study using bupivacaine 0.125% appeared effective in desensitizing the lower abdomen of ponies for up to 2 hours. Further research is required to apply this technique in horses undergoing celiotomy. Potentially larger volumes and/or higher concentrations of bupivacaine may be necessary to provide longer duration of action of the block.