A double-blind randomized controlled trial comparing dexamethasone and clonidine as adjuvants to a ropivacaine sciatic popliteal block for foot surgery

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.

Levobupivacaine Consumption in Automated Intermittent Bolus in Ultrasound Guided Subparaneural Sciatic Nerve Catheters: A Prospective Double-Blind Randomized Trial

Purpose

Continuous sciatic nerve blocks have proven benefits for postoperative analgesia after foot surgery. However, the optimal mode of administration remains a point of debate. Ultrasound guided subparaneural injection accelerates onset time and increases duration after a single shot sciatic nerve block. This double blind prospective randomized trial compares the 48-hour local anesthetic (LA) dose consumption of an automated intermittent bolus technique to a continuous infusion regimen in a subparaneural sciatic nerve catheter after hallux valgus surgery.

Patients and Methods

Patients scheduled for hallux valgus surgery were randomized to receive either a continuous infusion of levobupivacaine 0.125% at 5mL/h (group A) or an intermittent automated bolus of 9.8 mL every 2 hours with a background of 0.1 mL/h (group B), both with a PCA bolus of 6 mL and lockout of 30 minutes. The 48 hour LA consumption, PCA boluses, Numeric Rating Scale (NRS), satisfaction and return of normal sensation were recorded.

Results

Sixteen patients were excluded because of protocol violation or technical problems and 42 patients remained for analysis. The 48 hour ropivacaine consumption was higher in group A (293 ±60 mL) than group B (257±33 mL). The median and highest NRS scores and patient satisfaction were not statistically different between groups. Normal sensation returned after 75 ± 22 hours (group A) and 70 ± 17 hours (group B).

Conclusion

Programmed bolus administration in subparaneural sciatic nerve catheters reduces LA consumption 48 hours after surgery with equal analgesia and patient satisfaction. Return of sensation is variable and can last more than 75 hours.

Lateral popliteal block in foot and ankle surgery: Comparing ultrasound guidance to nerve stimulation. A prospective randomized trial

BACKGROUND

The popliteal block has several benefits in foot and ankle surgery. It reduces postoperative pain, limits the use of narcotics and facilitates early discharge. The aim of this prospective randomized trial was to evaluate whether ultrasound guidance improves block characteristics compared to the nerve stimulation technique in lateral popliteal blocks.

METHODS

Patients were randomized to receive either a lateral popliteal block using neurostimulation or ultrasound guidance. Block performance time, number of needle pricks, number of redirections were recorded. Pain upon admission to and discharge from post anesthesia care unit (PACU) was recorded. Block duration, patient satisfaction, pain at block site and amount of opioids used in PACU and between subsequent followup visits was recorded. Patients were followed for 12 weeks postoperatively.

RESULTS

There was no statistically significant difference between the two groups in terms of number of pricks, time for the block to wean, pain upon admission to PACU, amount of opioids received in PACU, pain upon discharge from PACU, pain at the operative site, pain at the block site, toe motor function and toe sensation. There was a statistically significant difference in the block procedure performance time between the two groups, with the control group being faster (P<0.0001). A significantly larger number of patients in the control group required more than three needle redirections (P=0.0060).

CONCLUSIONS

The lateral sciatic popliteal block using nerve stimulation had similar block characteristics and patient satisfaction with a significantly faster performance time compared to the ultrasound guided technique.

LEVEL OF EVIDENCE

Level I, prospective randomized study.

Fentanyl and clonidine as adjuncts to a mixture of local anesthetics in potentiating postoperative analgesia in supraclavicular block: A randomized controlled study

Background:

Brachial plexus block is popular for upper limb surgeries as it is effective for postoperative analgesia.

Aims:

The aim of the study was to compare fentanyl and clonidine as adjuncts to a mixture of local anesthetics in potentiating postoperative analgesia in the supraclavicular block.

Materials and Methods:

Sixty patients of the American Society of Anesthesiologist I and II undergoing upper limb surgeries lasting more than 30 min were included and randomly divided into two groups of 30 each. In clonidine (C) group, patients received 10 ml of 0.5% bupivacaine + 20 ml of 2% lignocaine with adrenaline (1:200,000) and 1 μg/kg clonidine diluted till 35 cc with normal saline. In fentanyl (F) group, patients received 10 ml of 0.5% bupivacaine + 20 ml of 2% lignocaine with adrenaline (1:200,000) and 1 μg/kg fentanyl diluted till 35 cc with normal saline. Patients were observed for onset and duration of sensory and motor blockade, duration of analgesia, postoperative pain, and adverse effects.

Results:

The mean onset of sensory block was faster in Group F (8.43 ± 2.897 min) as compared to 13.17 ± 2.451 min in Group C. The difference between the two groups was statistically strongly significant (P < 0.0001). There was a significant reduction in the onset of motor block in Group F (14.67 ± 1.84 min) compared to (18.17 ± 2.45 min) Group C with P < 0.0001 (statistically strongly significant). There was a significant increase in the duration of analgesia in Group C (16.63 ± 2.04 h) compared to Group F (8.79 ± 1.50 h) with P < 0.0001. There was bradycardia (pulse did not fall below 60) in two patients of Group C (treated with atropine intravenous [i.v.]). Two patients of Group F complained of nausea and vomiting once in the early hours of surgery for which ondansetron i.v. was given. There were no significant side effects in either of the groups.

Conclusion:

Both clonidine and fentanyl establish a good safety profile. Fentanyl ensures a faster onset of sensory and motor blockade, while clonidine ensures a longer duration of sensory and motor blockade as well as prolonged analgesia.

Effect of adding dexamethasone to ropivacaine for ultrasound-guided serratus anterior plane block in patients undergoing modified radical mastectomy: A preliminary trial

BACKGROUND AND AIMS

Ultrasound-guided serratus anterior plane (SAP) block is a field block with high efficacy. We studied the analgesic effect of the addition of dexamethasone to ropivacaine in SAP block for modified radical mastectomy (MRM).

METHODS

Sixty patients undergoing MRM were randomised into two groups. Patients in Group P (n = 30) received 0.375% ropivacaine (0.4 ml/kg) with normal saline (2 ml) and those in group D (n = 30) received 0.375% ropivacaine (0.4 ml/kg) with 8 mg of dexamethasone (2 ml) in ultrasound-guided SAP block. The primary objective was to compare the time to first rescue analgesia and the secondary objectives were to compare the intraoperative fentanyl requirement, total diclofenac and tramadol requirements, and occurrence of nausea and vomiting in 24 hours, postoperatively. The statistical analysis was done using Mann-Whitney U-test, Chi-square test, Fisher's exact test, and Kaplan Meier survival estimates.

RESULTS

More patients required rescue analgesia in 24 hours in group P (33%) than group D (10%, P = 0.04). The probability of a pain free-period was significantly higher in group D than group P (P = 0.03, log-rank test). Intra-operative fentanyl requirement and postoperative diclofenac and tramadol requirements were comparable in both the groups. The incidence of postoperative nausea and vomiting was significantly more in Group P than Group D.

CONCLUSION

Addition of dexamethasone to ropivacaine for SAP block increases the time to first rescue analgesic in the postoperative period.

Comparison of the effect of three different adjuvants on the analgesic duration of single injection interscalene brachial plexus block: a prospective, randomized, triple blinded clinical trial

BACKGROUND AND OBJECTIVES

Use of regional anesthesia can result in faster recovery and better patient satisfaction. Addition of perineural adjuncts to local anesthetics may improve the duration of analgesia, but there is a paucity of data comparing them in a single randomized trial. We compared the effects of three adjuncts clonidine, dexamethasone, and buprenorphine, on the duration of analgesia of interscalene brachial plexus block.

METHODS

160 patients, undergoing elective shoulder surgery, were randomized to four groups to receive an interscalene block with one of the following solutions: ropivacaine alone, ropivacaine with clonidine 75 µg, ropivacaine with dexamethasone 8 mg, or ropivacaine with buprenorphine 300 µg. The primary outcome variable was the duration of analgesia; secondary outcome measures were time to onset of the block, and the duration of sensory and motor blocks.

RESULTS

There was no statistically significant difference in the total analgesia time among the four groups; p=0.11. The pairwise comparison in analgesic time and 99% CI were: control versus clonidine (-1.94 hours (-7.33 to 3.12)), control versus dexamethasone (-4.16 hours (-9.50 to 0.58)) and control versus buprenorphine (-1.1 hours (-5.34 to 3.23)). There was no differences in block set-up time, or total sensory and motor block duration among the groups.

CONCLUSION

There was no significant improvement in the duration of analgesia with addition of any of the three adjuncts to interscalene blocks. However, there was a larger than expected variability in patient response, hence the study may have been underpowered for the primary outcome.

The Importance of the Saphenous Nerve Block for Analgesia Following Major Ankle Surgery: A Randomized, Controlled, Double-Blind Study

BACKGROUND AND OBJECTIVES

Major ankle surgery causes intense postoperative pain, and whereas the importance of a sciatic nerve block is well established, the clinical significance of a supplemental saphenous nerve block has never been determined in a prospective, randomized, double-blind, placebo-controlled trial. We hypothesized that a saphenous nerve block reduces the proportion of patients experiencing significant clinical pain after major ankle surgery.

METHODS

Eighteen patients were enrolled and received a popliteal sciatic nerve block. Patients were randomized to single-injection saphenous nerve block with 10 mL 0.5% bupivacaine with 1:200,000 epinephrine or 10 mL saline (Fig. 1). Primary outcome was the proportion of patients reporting significant clinical pain, defined as a score greater than 3 on the numerical rating scale. Secondary outcomes were maximal pain and analgesia of the cutaneous territory of the infrapatellar branch of the saphenous nerve.

RESULTS

Eight of 9 patients in the placebo group reported significant clinical pain versus 1 of 9 patients in the bupivacaine-epinephrine group (P = 0.003). Maximal pain was significantly lower in the active compared with the placebo group (median, 0 [0-0] vs 5 [4-6]; P = 0.001). Breakthrough pain from the saphenous territory began within 30 minutes after surgery in all cases. Sensory testing of the cutaneous territory of the infrapatellar branch of the saphenous nerve showed correlation between pain reported in the anteromedial ankle region and the intensity of cutaneous sensory block in the anteromedial knee region.

CONCLUSIONS

The saphenous nerve is an important contributor to postoperative pain after major ankle surgery, with significant clinical pain appearing within 30 minutes after surgery.

CLINICAL TRIALS REGISTRATION

This study has been registered at ClinicalTrials.gov, identifier NCT02697955.

The effect of perineural dexamethasone on duration of sciatic nerve blockade: a randomized, double-blind study

BACKGROUND

Major hindfoot and ankle surgery is associated with severe postoperative pain, which is effectively alleviated by combined sciatic and saphenous nerve blockade. Local anaesthetics with added dexamethasone consistently prolongs the duration of pain relief compared to local anaesthetics alone. However, whether the extended duration of pain relief is due to an effect on duration of sensorimotor block per se vs. systemic absorption of the dexamethasone is still not fully elucidated. We aimed to investigate the postoperative duration of sensorimotor blockade with either dexamethasone or saline added to bupivacaine-epinephrine.

METHODS

Fifty six patients scheduled for surgery were randomly assigned to a popliteal sciatic nerve block of 18 ml 0.5% bupivacaine-epinephrine with either 2 ml of 0.4% dexamethasone or 2 ml 0.9% normal saline added. Sensory and motor functions were tested every 30 min until normalized nerve functions. Primary outcome was time until complete return of sensorimotor functions.

RESULTS

Mean (SD) time until return of normal sensory and motor functions was 26 (6) vs. 16 (4) hours, P < 0.001, postponing block remission by 10 (95% CI: 8-13) hours. Mean (SD) time until first opioid request was 34 (11) vs. 15 (7) hours, P < 0.001, extending first opioid request by 19 (95% CI: 13-25) hours. Total oral morphine equivalents administered 0-48 h differed significantly between the two groups by 39 (95% CI: 23-55) mg.

CONCLUSIONS

Addition of 8 mg dexamethasone to 0.5% bupivacaine-epinephrine significantly prolongs the duration of sensorimotor popliteal sciatic nerve blockade, and reduces pain and opioid consumption in patients after major hind foot and ankle surgery.

Mexiletine co-injected with clonidine increases the quality and duration of cutaneous analgesia in response to skin pinpricks in the rat

The goal of the experimental design was to assess the cutaneous analgesic effect of mexiletine by co-injection with clonidine. The effect of nociceptive block was evaluated according to the inhibition of the cutaneous trunci muscle reflex (CTMR) in response to skin pinpricks in rats. The dose-related analgesic effect of mexiletine alone or mexiletine co-administrated with clonidine was constructed after subcutaneous injection. Subcutaneous injections of mexiletine elicited dose-related cutaneous analgesia. Compared with mexiletine (1.8μmol), adding clonidine to mexiletine (1.8μmol) solutions for skin nociceptive block potentiated and prolonged the action (p<0.01). Mexiletine (6μmol) combined with clonidine extended the duration of cutaneous analgesia when compared with mexiletine (6μmol) alone (p<0.01). Co-administration of clonidine increases the potency and extends the duration of cutaneous analgesia by mexiletine, and the minimal dose of clonidine to intensify the analgesic effect is 0.06μmol.