Effective local anaesthetic volumes for sciatic nerve blockade: a clinical evaluation of the ED₉₉

Abstract

SummaryPrevious results in volunteers have indicated the effective dose in 99% of subjects (ED 99 ) of local anaesthetic volume to be 0.10 ml.mm À2 of cross-sectional nerve area for sciatic nerve blockade. The objective of this prospective, randomised, double-blind study was to investigate the ED 99 of local anaesthetic for ultrasound-guided sciatic nerve blockade in patients undergoing foot surgery, according to Dixon's up-and-down method and probit analysis. A starting volume of 0.20 ml local anaesthetic per mm 2 cross-sectional nerve area was used. If surgical anaesthesia was judged to be adequate, the volume of local anaesthetic for the next case was reduced by 0.02 ml.mm À2 , until the first block failed. Thereafter, the volume of local anaesthetic was increased by 0.02 ml.mm À2. The ED 99 volume of local anaesthetic for ultrasound-guided sciatic nerve blockade was calculated to be 0.15 ml.mm À2 cross-sectional nerve area, which is higher than the previously evaluated ED 99 volume in volunteers.

Ultrasound‐Guided Subgluteal Sciatic Nerve Perineural Injection: Report on Safety and Efficacy at a Single Institution

“…With regard to therapeutic efficacy, anesthesiology groups have reported on the efficacy of US-guided sciatic nerve blocks at the distal thigh 33,34 and in the subgluteal region. 27 To our knowledge, there is only 1 previously published study reporting on the efficacy of therapeutic perineural sciatic nerve injection using a USguided transgluteal approach; this study of 10 patients reported a high rate of symptom reduction after a follow-up period of 2 months, although 2 of 10 patients had to undergo repeated injections after 2 weeks for persistent pain.…”

A randomised controlled trial comparing two popliteal nerve catheter tip positions for postoperative analgesia after day‐case hallux valgus repair

“…Ultrasound-guided peripheral nerve blocks offer a number of advantages when compared with nerve stimulator techniques, both in terms of volumes of local anaesthetic administered and success rate [10][11][12]. The primary endpoint was postoperative local anaesthetic consumption in the first 48 h. A predictable consumption of local anaesthetic is a fundamental characteristic for continuous peripheral nerve blocks in the outpatient setting.…”

“…This confirms that tibial nerve catheter placement could be a reliable analgesic technique for ambulatory foot surgery. Ultrasound-guided peripheral nerve blocks offer a number of advantages when compared with nerve stimulator techniques, both in terms of volumes of local anaesthetic administered and success rate [10][11][12]. High-definition imaging has contributed to a better understanding of the structure of the sciatic nerve [13].…”

Minimum effective local anesthetic volume for surgical anesthesia by subparaneural, ultrasound-guided popliteal sciatic nerve block

“…However, in general, the evaluation times of previous studies have been diverse (e.g., 30, 45, and 60 minutes) because the onset time of sciatic nerve block using ultrasound is 30 to 60 minutes. [9–11,17] …”

“…There have been a few studies on effective volumes for US-guided PSNB via the perineural route. [9–11] However, as far as we know, no previous study has sought to determine the minimum effective volume for surgical anesthesia via the subparaneural route. The purpose of the present study was to determine the MEV 50 and ED 90 for surgical anesthesia in US-guided PSNB via subparaneural injection.…”