Question:
In patients having ankle or hindfoot surgery, does the administration of continuous nerve blockade confer greater postoperative pain relief than single bolus peroneal and tibial nerve block?
Design:
Randomized (allocation concealed), blinded (patients and outcome assessors), controlled trial with follow-up to seventy-two hours postoperatively.
Setting:
A hospital orthopaedic surgery department in Basingstoke, United Kingdom.
Patients:
Fifty-four patients who were scheduled for major ankle or hindfoot surgery (ankle arthrodesis, hind or midfoot arthrodesis, ankle replacement, calcaneal osteotomy plus tendon transfer, tibiotalocalcaneal arthrodesis, pantalar arthrodesis, and tendo-Achilles reconstruction). Follow-up was complete.
Intervention:
Patients were allocated to a continuous infusion of 0.25% bupivacaine (4 mL/h with 1 mL patient-controlled bolus per hour) for seventy-two hours (n = 27) or to a continuous infusion of 0.9% normal saline solution for seventy-two hours (n = 27). Both groups received an initial 20-mL bolus of bupivacaine 0.5%.
Main outcome measures:
The primary outcome measure was the median visual analog scale (VAS) score (0 [no pain] to 10) for pain for the first seventy-two hours after surgery. The secondary outcome was the need for supplemental opioid analgesia.
Main results:
Analysis was by intention to treat. During the postoperative period, the mean VAS scores were significantly lower in the continuous infusion group than in the control group (Table). The median total morphine requirements were lower in the continuous infusion group than in the control group (30 vs. 52.5 mg, p = 0.012).
Conclusion:
In patients having ankle or hindfoot surgery, the continuous infusion of bupivacaine via a pain pump provided better postoperative pain relief than that provided by normal saline solution.
Coughlin Foot and Ankle Clinic at Saint Alphonsus Boise, Idaho
Nerve block for foot and ankle surgery has the potential to reduce the need for general anesthesia, duration of hospitalization, and the need for postoperative analgesics.
In this study by Elliot and colleagues, patients receiving continuous infusion had lower pain scores and lower use of postoperative opioid analgesics at seventy-two hours than did patients receiving single injection. The take-home message, however, was that despite these significant differences, the authors question the benefit given the time involved in placement of the catheter and the cost of the catheter and pump compared with the time and cost associated with a single injection. Both groups had low pain scores. Catheter complications included leakage, air bubbles blocking the catheter, and dislodgment.
Issues not considered in this study were the level of the block and the means of localizing the injection. Many anesthesiologists use ultrasound to improve localization for nerve blocks and to perform a more proximal injection (in the area of the sciatic nerve), both of which may increase the duration of the single shot blocks. Furthermore, a complete cost consideration must include not just the amount and cost of opioid analgesics, but also the cost of hospital stay. If patients remain in the hospital with either modality, this can result in substantial costs. As a side note, the infusion device used in this study has been taken off the market by the Stryker Corporation in the United States.
In summary, this study demonstrated only a moderate difference in pain scores and opiate usage, suggesting that perhaps single injection may be used in situations where less pain is anticipated. Some surgical procedures demand more aggressive pain control than others, and a physician should select the modality of pain management accordingly.