Preemptive subcutaneous tramadol for post-operative pain in lower abdomen surgeries: A randomized double blinded placebo-control study

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.

Adjuncts to local anesthetic wound infiltration for postoperative analgesia: a systematic review

Local anesthetics (LAs) are commonly infiltrated into surgical wounds for postsurgical analgesia. While many adjuncts to LA agents have been studied, it is unclear which adjuncts are most effective for co-infiltration to improve and prolong analgesia. We performed a systematic review on adjuncts (excluding epinephrine) to local infiltrative anesthesia to determine their analgesic efficacy and opioid-sparing properties. Multiple databases were searched up to December 2019 for randomized controlled trials (RCTs) and two reviewers independently performed title/abstract screening and full-text review. Inclusion criteria were (1) adult surgical patients and (2) adjunct and LA agents infiltration into the surgical wound or subcutaneous tissue for postoperative analgesia. To focus on wound infiltration, studies on intra-articular, peri-tonsillar, or fascial plane infiltration were excluded. The primary outcome was reduction in postoperative opioid requirement. Secondary outcomes were time-to-first analgesic use, postoperative pain score, and any reported adverse effects. We screened 6670 citations, reviewed 126 full-text articles, and included 89 RCTs. Adjuncts included opioids, non-steroidal anti-inflammatory drugs, steroids, alpha-2 agonists, ketamine, magnesium, neosaxitoxin, and methylene blue. Alpha-2 agonists have the most evidence to support their use as adjuncts to LA infiltration. Fentanyl, ketorolac, dexamethasone, magnesium and several other agents show potential as adjuncts but require more evidence. Most studies support the safety of these agents. Our findings suggest benefits of several adjuncts to local infiltrative anesthesia for postoperative analgesia. Further well-powered RCTs are needed to compare various infiltration regimens and agents.

Protocol registration

PROSPERO (CRD42018103851) (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=103851)

A single dose of tramadol in continuous wound analgesia with levobupivacaine does not reduce post-sternotomy pain: a randomized controlled trial

Background

Medial sternotomy is commonly used in cardiac surgery, although it results in intense post-operative pain. The placement of a sternal wound catheter for the administration of local anesthetic represents an effective technique. An initial bolus of tramadol in the sternal wound catheter could potentiate the effect of the local anesthetic and decrease both the post-operative pain and the morphine consumption.

Patients and methods

We conducted a prospective, randomized, double-blind study at the University Hospital Center, Dijon, France. Patients requiring scheduled or non-extreme emergency surgery for valve disease, aorta disease, atrial myxoma, or coronary artery bypass graft via sternotomy were included. A sternal wound catheter was inserted at the end of the surgery. The patients were randomized to receive either a 2 mg/kg bolus of tramadol (n=80) or a placebo (n=80) in the wound catheter. The bolus administration was followed by a continuous infusion of 1.25% levobupivacaine for the first 48 hrs following surgery. The patients’ morphine consumption during the first 48 hrs after extubation was recorded. The other investigated variables were the patients’ rescue analgesia, arterial blood gasses, and length of stay in the intensive care unit and in hospital, as well as the incidence of chronic pain at the four-month follow-up point.

Results

The morphine consumption was found to be comparable in the two groups (38 mg vs 32 mg, p=0.102). No effect was found in terms of the arterial blood gasses, lengths of stay, or incidence of chronic pain.

Conclusion

The addition of tramadol to the local anesthetic delivered via a wound catheter following sternotomy did not reduce the patients’ post-operative morphine consumption.

Trial registration

Clinicaltrials.gov identifier: NCT02851394.

Comparative Study between Preemptive and Postoperative Intra-Articular Injection of Levobupivacaine and Tramadol for Control of Postoperative Pain

Background:

This study had been formulated to evaluate and compare the analgesic effect of preemptive (PE), postoperative (PO), and combined knee intra-articular injection (IAI) of levobupivacaine and tramadol after knee arthroscopy.

Materials and Methods:

A total of 220 patients assigned for therapeutic knee arthroscopy were divided into four equal groups. Patients in Group C received IAI of 20 mL (0.5%) levobupivacaine preoperative, meanwhile patients in Group PE received IAI of 18 mL (0.5%) levobupivacaine with 100 mg tramadol (2 mL). Patients in Group PO received IAI of 18 mL (0.5%) levobupivacaine with 100 mg tramadol (2 mL) postoperatively, whereas patients in Group PE/PO received IAI of 19 mL (0.25%) levobupivacaine with 50 mg tramadol (1 mL) preoperatively and postoperatively. Numeric rating scale (NRS) had been used to assess pain sensation. Duration till the first request of rescue analgesia and number of requests were recorded.

Results:

NRS scores were significantly higher in Group C compared to other groups and in Group PE in comparison to PO and PE/PO groups. Frequency of rescue analgesia requests was significantly higher in Group C with significantly higher mean times of requests, while was significantly lower in Group PE/PO with significantly lower mean times of requests when compared to groups PE and PO.

Conclusions:

PE levobupivacaine and tramadol IAI provided satisfactory level of PO analgesia after therapeutic arthroscopy. However, combined PE and PO levobupivacaine and tramadol IAI of half dose provided PO analgesia superior to that provided by either PE or PO full-dose IAI.

Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

In this work, poloxamer (PL)-based binary hydrogels, composed of PL 407 and PL 188, were studied with regard to the physicochemical aspects of sol-gel transition and pharmaceutical formulation issues such as dissolution-release profiles. In particular, we evaluated the cytotoxicity, genotoxicity, and in vivo pharmacological performance of PL 407 and PL 407-PL 188 hydrogels containing tramadol (TR) to analyze its potential treatment of acute pain. Drug-micelle interaction studies showed the formation of PL 407-PL 188 binary systems and the drug partitioning into the micelles. Characterization of the sol-gel transition phase showed an increase on enthalpy variation values that were induced by the presence of TR hydrochloride within the PL 407 or PL 407-PL 188 systems. Hydrogel dissolution occurred rapidly, with approximately 30%-45% of the gel dissolved, reaching ~80%-90% up to 24 hours. For in vitro release assays, formulations followed the diffusion Higuchi model and lower K(rel) values were observed for PL 407 (20%, K(rel) = 112.9 ± 10.6 μg · h(-1/2)) and its binary systems PL 407-PL 188 (25%-5% and 25%-10%, K(rel) =80.8 ± 6.1 and 103.4 ± 8.3 μg · h(-1/2), respectively) in relation to TR solution (K(rel) =417.9 ± 47.5 μg · h(-1/2), P<0.001). In addition, the reduced cytotoxicity (V79 fibroblasts and hepatocytes) and genotoxicity (V79 fibroblasts), as well as the prolonged analgesic effects (>72 hours) pointed to PL-based hydrogels as a potential treatment, by subcutaneous injection, for acute pain.