The ankle clonus test is not a clinically useful measure of spinal cord integrity in children.
OBJECTIVE
Bilateral flexion-induced ankle clonus has been proposed as a test of spinal cord integrity during anesthesia for scoliosis surgery. The purpose of this study was to establish the reliability of this test in normal children emerging from volatile anesthesia. A secondary objective was to determine if there was a difference in the validity of this test with either sevoflurane or isoflurane anesthesia.


METHODS
In a randomized, prospective blinded clinical trial, 32 healthy children aged three to 13 yr, were randomized to receive either isoflurane (Group I, n = 15) or sevoflurane (Group S, n = 17) for maintenance of anesthesia during dental restorative surgery. During emergence, an observer, blinded to group allocation, recorded ankle clonus scores (number of beats to a maximum of 5 on each side) at 60-sec intervals until tracheal extubation. End-tidal anesthetic concentration was measured contemporaneously.


RESULTS
Non-sustained ankle clonus was elicited in a majority of children during emergence: 13 (87%) patients in Group I and 15 (88%) in Group S demonstrated at least non-sustained or unilateral clonus. However, bilateral sustained (> 5 beats.min(-1)) ankle clonus occurred in only four (27%) patients in Group I and four (24%) patients in Group S (P = 0.83).


CONCLUSIONS
We conclude that the specificity of the ankle clonus test is too low to be clinically useful as a measure of spinal cord integrity in children, both when isoflurane and sevoflurane are used as the primary anesthetic agent.
Ewen
Alastair
A
Division of Pediatric Anesthesia, Alberta Children's Hospital at University of Calgary, 1820 Richmond Road SW, Calgary, Alberta T2T 5C7, Canada.
Cox
Robin G
RG
Davies
Sîon A
SA
Luntley
Jeremy B
JB
Rubin
Yair
Y
Fick
Gordon H
GH
Bart
Bevin B
BB
D000293:Adolescent; D000843:Ankle Joint / Q000502:physiology*; D001831:Body Temperature / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology; D011446:Prospective Studies; D012018:Reflex; D000077149:Sevoflurane; D013119:Spinal Cord Injuries / Q000175:diagnosis*; D013131:Spine / Q000601:surgery*
D008738:Methyl Ethers; D000077149:Sevoflurane; D007530:Isoflurane