Arthrosis, Unspecified, Ankle and Foot Clinical Trial
Official title:
Comparison of the Effect of a Single Shot Saphenous Block With Plain Bupivacaine vs. Protracted Bupivacaine Mixture as a Supplement to Continuous Sciatic Catheter After Major Ankle and Foot Surgery
This study focuses on optimizing the postoperative pain treatment after major foot and ankle surgery by prolonging the duration of the ultrasound-guided saphenous block. The currently used single shot saphenous block only covers half of the pain intensive period from the saphenous territory, which results in a sharp, break-through pain requiring opioids. The hypothesis is that this protracted mixture will keep the patients free of pain without the use of opioids for the entire pain intensive period and thus increase rehabilitation and patients' satisfaction.
Half of the patients will receive a single shot saphenous block with 10 mL
bupivacaine-adrenalin and 1 mL of sodium chloride solution, while the other half will
receive 10 mL of bupivacaine-adrenalin and 1 mL of dexamethasone.
The block is strictly a sensory block because it is a selective, sub-sartorial saphenous
block at mid-thigh level without any anesthetic effect on the femoral nerve.
The adjuvant dexamethasone has increasingly become a subject of interest regarding a
protracted effect, which has been shown in several studies. However, the precise mechanism
of action remains speculative, and the results are contradictory regarding the discussion
whether the effect is systemic or local. The effect may stem from decreased nociceptive
C-fibre activity via a direct action on glucocorticoid receptors and inhibitory potassium
channels. Another suggestion is a vasoconstrictive effect, which reduces the systemic uptake
of local anaesthetics or a systemic anti-inflammatory effect.
Prolonging the effect of the single shot saphenous block by adding dexamethasone will reduce
the need for opioids, which will reduce the risk of adverse effects like nausea, vomiting
and respiratory depression. Furthermore, newer studies show that inadequate pain alleviation
in the early postoperative period is a risk factor in developing chronic persistent pain.
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Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention