Prilocaine in lumbosacral plexus block – general efficacy and comparison of nerve stimulation amplitude

Abstract

The significance of the threshold amperage of peripheral nerve stimulation (PNS) for the efficacy and latency of sciatic block is shown in a controlled randomized study of stimulation amplitude. In all cases the block was complete within a short time when the threshold amperage was 0.3 mA or less. Incomplete motor and sensory blocks occurred with higher stimulation amplitudes of 0.5 and 1.0 mA. In view of these results a prospective study of the clinical efficacy of 852 combined sciatic/3-in-1 blocks using prilocaine, and performed by means of peripheral nerve stimulation was carried out. No CNS or cardiovascular complications, no problems resulting from methaemoglobinaemia and, above all, no nervous lesions were observed. The limiting factor for surgery of the lower limb with this method of anaesthesia is the tolerance of the femoral tourniquet which depends mainly on the efficacy of the 3-in-1 block. Ninety-one per cent of the combined blockades were primarily successful when there was no tourniquet at all, and 87% when the tourniquet was placed on the lower leg. In the course of surgery with a femoral pneumatic tourniquet, only 55% of the blocks did not require supplement when 20 ml of 1% prilocaine was used for the 3-in-1 block, while 72% and 74% were efficacious with 30 ml and 35 ml, respectively. The efficacy of the sciatic block proved to be extremely high (> 95%), its success depending on the dosage of the local anaesthetic and correct execution of the peripheral nerve stimulation.

Safety and Efficacy of the Infraclavicular Nerve Block Performed at Low Current

“…Kaiser et al. demonstrated high success rates without complications at low current levels for lower extremity blocks, while failures occurred if higher current levels (0.5 or 1.0 mA) were accepted 19 . Our results with upper extremity blocks concur with Kaiser et al.’s experience.…”

Stop, You Are Both Right: A Role for Both the Nerve Stimulator and Ultrasound‐Guided Regional Anesthesia Techniques

“…It is important to note that in their study of almost 250 patients who underwent infraclavicular blockade with the nerve stimulator technique, performed at 0.3 mA or less, none of the patients had neurologic damage referable to the technique. This is consistent with the findings of Kaiser et al., 2 where lower extremity block success rate was high with 0.1 and 0.3 mA, but fell off significantly at 0.5 and 1.0 mA levels. In their series, there were no neurologic complications in blocks performed at lower mA levels.…”

Elektrische Nervenstimulation in Abhängigkeit von der benutzten Impulsbreite

“…Bereits in früheren Studien [8,9,10,11] wurden Stromstärken verschiedener Impulsbreiten bezüglich ihrer motorischen Antwort und des Blockadeerfolgs bestimmt. Denn: Bei Toleranz hoher Impulsbreiten oder hoher Reizstromstärken ist die Nadel weiter vom Nerven entfernt und die Gefahr einer inkompletten Blockade erhöht; bei Anwendung zu niedriger Reizstromstärken oder zu geringer Impulsbreiten steigt das Risiko der intraneuralen Injektion bzw.…”

“…Bereits in früheren Studien wurden die Stromstärken, die zu vergleichbaren Muskelkontraktionen führten, bei Impulsbreiten von 1 ms und 0,1 ms verglichen [8,11]. Hier kommt man zu dem Ergebnis, dass Reizstromstärken von 0,2-0,5 mA bei einer Impulsbreite von 0,1 ms vergleichbar sind mit Äquivalenzstromstärken von 0,05-0,2 mA bei einer Impulsbreite von 1 ms.…”

“…Die Stimulation mit 0,1 ms und die Injektion bei dann 0,3 mA ist ein in der Literatur oft durchgeführtes Verfahren, bei welchem nie Nervenschäden beschrieben worden sind [8,9,10,11,16,17]. Die Stimulation mit 0,1 ms und die Injektion bei dann 0,3 mA ist ein in der Literatur oft durchgeführtes Verfahren, bei welchem nie Nervenschäden beschrieben worden sind [8,9,10,11,16,17].…”