Initial placement and secondary displacement of a new suture‐method catheter for sciatic nerve block in healthy volunteers: a randomised, double‐blind pilot study

Abstract

We performed a randomised double-blind pilot study in 16 healthy volunteers to investigate the success rate for placing a new suture-method catheter for sciatic nerve block. A catheter was inserted into both legs of volunteers and each was randomly allocated to receive 15 ml lidocaine 2% through the catheter in one leg and 15 ml saline in the other leg. Successful placement of the catheter was defined as a 20% decrease in maximum voluntary isometric contraction for dorsiflexion of the ankle. Secondary outcomes were maximum voluntary isometric contraction for plantar flexion at the ankle, surface electromyography and cold sensation. After return of motor and sensory function, volunteers performed standardised physical exercises; injection of the same study medication was repeated in the same leg and followed by motor and sensory assessments. Fifteen of 16 (94%; 95%CI 72-99%) initial catheter placements were successful. The reduction in maximum voluntary isometric contraction and surface electromyography affected the peroneal nerve more often than the tibial nerve. Eleven of 15 (73%; 95%CI 54-96%) catheters remained functional with motor and sensory block after physical exercise, and the maximal displacement was 5 mm. Catheters with secondary block failure were displaced between 6 and 10 mm. One catheter was displaced 1.8 mm that resulted in a decrease in maximum voluntary isometric contraction of less than 20%. After repeat test injection, 14 of the 16 volunteers had loss of cold sensation. Neither motor nor sensory functions were affected in the legs injected with placebo. We conclude that the suture-method catheter can be placed with a high success rate, but that physical exercise may cause displacement.

Volume of ropivacaine 0.2% and common peroneal nerve block duration: a randomised, double‐blind cohort trial in healthy volunteers

“…Placement of the catheter delivery orifice was done by dynamic, in‐plane visualisation of the catheter and its built‐in echogenic markings, as well as intermittent injections of isotonic saline through the catheter. Placement of the catheter was adjusted until an injection of isotonic saline resulted in perineural spread . A maximum of 5 ml of isotonic saline was used for the entire catheter insertion procedure.…”

Promoting the use of peripheral nerve catheters: better catheter accuracy or more user‐friendliness?

“…The curved needle design theoretically also confers better needle shaft echogenicity. The latest study confirms a high success rate for initial catheter placement using the author's specific laboratory sensory and motor block definition for ‘success’ . This initial high success persisted after subjects performed vigorous exercises including knee flexion, hip flexion, hip adduction and stair climbing .…”

“…The latest study confirms a high success rate for initial catheter placement using the author's specific laboratory sensory and motor block definition for ‘success’ . This initial high success persisted after subjects performed vigorous exercises including knee flexion, hip flexion, hip adduction and stair climbing . The study involved healthy volunteers, all with a BMI < 30 kg.m −2 , each receiving bilateral catheters but with random allocation of each catheter to either local anaesthetic or placebo.…”

“…In this issue of the Journal, Lyngeraa et al report a further investigation into the potential advantages of the ‘suture‐method’ perineural catheter system for popliteal sciatic nerve block . This novel design consists of a curved 100–160 mm needle with an echogenically‐enhanced catheter attached to the proximal end of the needle.…”

Effect of a lateral infraclavicular brachial plexus block on the axillary and suprascapular nerves as determined by electromyography – a cohort study

“…Several methods for evaluating regional anaesthesia exist , but electromyography has never been widely used. To our knowledge, during the last 20 years, only three studies have used electromyography to evaluate nerve blocks in relation to regional anaesthesia even though this technology offers obvious benefits . Electromyography makes it possible to measure the effect of a nerve block on individual muscles and compared with more traditional testing methods of sensory and motor functions, it delivers a continuous variable that offers greater resolution and different statistical possibilities .…”