Abstract
Purpose
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).
Conclusion
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.
Résumé
Objectif
Le clonus du pied bilatéral induit par la flexion a été proposé comme test de l’intégrité de la moelle épinière pendant l’anesthésie pour une opération de scoliose. Le but de notre étude était d’établir la fiabilité de ce test chez des enfants normaux au réveil d’une anesthésie avec agent volatil. Un objectif secondaire était de déterminer s’il y avait une différence de validité du test avec l’anesthésie au sévoflurane ou à l’isoflurane.
Méthode
Dans une étude clinique randomisée, prospective aveugle, 32 enfants de 3 à 13 ans ont été répartis au hasard et ont reçu de l’isoflurane (Groupe I, n = 15) ou du sévoflurane (Groupe S, n = 17) pour le maintien de l’anesthésie pendant une restauration dentaire chirurgicale. Pendant le retour à la conscience, un observateur impartial a enregistré les scores de clonus du pied (nombre de battements jusqu’à un maximum de 5 de chaque côté) à intervalles de 60 s jusqu’à l’extubation endotrachéale. La concentration télé-expiratoire d’anesthésique a été mesurée aux mêmes moments.
Résultats
Un clonus non soutenu a été obtenu chez la majorité des enfants pendant le retour à la conscience : 13 (87 %) patients du Groupe I et 15 (88 %) du Groupe S ont présenté au moins un clonus non soutenu ou unilatéral. Cependant, un clonus bilatéral soutenu (> 5 battements·min-1) est survenu chez seulement 4 (27 %) patients du Groupe I et 4 (24 %) du Groupe S (P= 0,83).
Conclusion
La spécificité du test de clonus du pied est trop faible pour être cliniquement significative comme mesure de l’intégrité de la moelle épinière chez les enfants, autant avec l’isoflurane qu’avec le sévoflurane comme anesthésique principal.
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Ewen, A., Cox, R.G., Davies, S.A. et al. The ankle clonus test is not a clinically useful measure of spinal cord integrity in children. Can J Anesth 52, 524–529 (2005). https://doi.org/10.1007/BF03016533
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DOI: https://doi.org/10.1007/BF03016533