A comparison of the onset time of complete blockade of the sciatic nerve in the application of ropivacaine and its equal volumes mixture with lidocaine: a double-blind randomized study

Abstract

BackgroundThe purpose of the current study is to create a new mixture of local anesthetics-one with a short time of block development and short action term (5 ml of 1% lidocaine solution) and another with a longer time of anesthesia development and a long analgetic effect (5 ml of 0.75% ropivacaine)-for use during surgical operations on extremities. The primary end point was the development of the complete sensory block of the sciatic nerve.MethodsSixty blocks of sciatic nerve were used in a double-blind randomized research, under ultrasonic guidance, using an electric stimulator with the peripheral nerves. Sixty patients were divided into 3 equal groups. In the first group, a sciatic nerve block was performed with 5 ml of 0.75% ropivacaine solution (37.5 mg); in the second group, 10 ml of 0.75% ropivacaine solution (75 mg) was used and, in the third group, a mixture of 5 ml of 0.75% ropivacaine (as above) and 5 ml of 1% lidocaine solution (50 mg) was used. The assessment of the time required for developing sensory and motor blocks was carried out from the beginning of local anesthetic solution injection in the fascial sheath of the sciatic nerve.ResultsDemographic data of patients were identical in the three sample groups. The time required for achieving a complete motor and sensory block was reduced due to the mix of the 1% lidocaine solution with the 0.75% ropivacaine solution. The time required for achieving a complete sensory block in groups treated with 5 and 10 ml ropivacaine was 45 (40-48) and 30 (28-30) min, respectively, in contrast with 12 (10-13) min when the mixture of anesthetics was applied (P < 0.01). There was no difference in analgesic duration in the postoperative period among groups at P > 0.05.ConclusionsThe mixture of 5 ml of 1% lidocaine with 5 ml of 0.75% ropivacaine leads to a reduction in the time required for the development of complete sensory and motor blocks of the sciatic nerve, without reducing postoperative analgesia time.

Comparison of Time Development of the Sciatic Nerve Blockade Performed with 1% Lidocaine Subgluteal and Popliteal Approach under Ultrasound Guidance

“…It is also suggested that the time of development of anesthesia for the same amount of local anesthetic should lengthen when the distal blockade is being performed because connective tissue is the main obstacle to the diffusion of anesthetic to axons [4]. Indirectly, the hypothesis by N. Moayeri et al about the amount of connective tissue as the principal obstacle to the diffusion of local anesthetic blocking the sciatic nerve was previously confirmed in our study where we proved that while performing the posterior blockade of the sciatic nerve under ultrasound guidance the reduction of the amount of 0.75% ropivacaine solution from 10 ml to 5 ml significantly increases the time of the development of complete sensory and motor blocks [19]. Our data acquired for lidocaine confirm the results obtained by M. Taboada et al for ropivacaine and mepivacaine which indicated the increase of the time of the popliteal sciatic nerve blockade [6] [7].…”

The analgesic efficacy of a single injection of ultrasound-guided retrolaminar paravertebral block for breast surgery: a prospective, randomized, double-blinded study

“…Group R received a single injection of the RLB with 30 mL of local anesthetic mixture (0.75% ropivacaine 20 mL + 2% lidocaine 10 mL) and IV-PCA. We planned to use a mixture of ropivacaine and lidocaine to reduce the onset time of the RLB without reducing postoperative analgesia duration [ 15 , 16 ].…”

Combined Lumbar-Sacral Plexus Block in High Surgical Risk Geriatric Patients undergoing Early Hip Fracture Surgery

“…In this study, the authors designed the use of a 20-ml mixture of rapid-acting agent with short duration of effect (10-ml of 2% lidocaine with epinephrine 1:200,000), and long-acting agent with long duration of effect (10-ml of 0.5% levobupivacaine) - which was different from the previous studies 14 - 16 . This - combined local anaesthetics (LA) solution would result in an early aneesthetic effect (approximately 20 minutes) which allow the anaesthesiologists to perform two blocks without delay without the need to use a high dose of levobupivacaine 25 , and also have a similar duration of analgesic benefit extended beyond six hours - comparable to the other studies 14 - 16 . Moreover, we also found that 20 mL of LA is sufficient for effective lumbar plexus block without serious complications like bilateral anesthesia (from unintentionally bilateral intrathecal/epidural drug spreading) or vascular administration of LA that had seen in traditional lumbar plexus block with large LA volumes (30-40 mL) 26 .…”