Evaluation of a proximal block site and the use of nerve-stimulator-guided needle placement for posterior tibial nerve block.
BACKGROUND
Posterior tibial nerve (PTN) block has traditionally been performed in the para-medial malleolar area without nerve stimulator (NS) guidance. The PTN can also be blocked proximally (7 cm) above the medial malleolus in the subfascial plane between the flexor hallucis longus and flexor digitorum longus tendons. In this study we compared the frequency of successful PTN block at the traditional distal (D) site (2 cm above the medial malleolus) with and without NS guidance. We also compared block success and latency at the D site versus the proximal (P) block site.


METHODS
Subjects were randomized to P-NS (n = 45), D-NS (n = 45), or D without NS (n = 45). Levobupivacaine 0.625%, 0.15 mL/kg was used for all blocks. Pinprick sensory anesthesia was evaluated in the distribution of the medial plantar, lateral plantar, and medial calcaneal nerves. PTN block was considered successful if surgical anesthesia was achieved in all PTN distributions.


RESULTS
The frequency of successful PTN block was greater for D-NS (100%) and P-NS (93.5%), compared with D (73.3%) (P = 0.02). Median latency to complete block was less for D-NS (8 min, 95% CI 7-9 min) than D (20 min, 95% CI 13-26 min) (P < 0.01) and P-NS (15 min, 95% CI 12-18 min) (P = 0.04).


CONCLUSIONS
NS-guided needle placement improves the success and decreases the latency to onset of complete PTN block at the D site. The P approach to PTN block may be a useful alternative to the traditional D site approach, particularly in patients with restricted access to the D site.
Doty
Robert
R
Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. r-dotyjr@northwestern.edu
Sukhani
Radha
R
Kendall
Mark C
MC
Yaghmour
Edward
E
Nader
Antoun
A
Brodskaia
Alina
A
Kataria
Tripti C
TC
McCarthy
Robert
R
D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation* / Q000379:methods*; D011446:Prospective Studies; D016037:Single-Blind Method; D013979:Tibial Nerve / Q000187:drug effects / Q000502:physiology
D000779:Anesthetics, Local