SLR - May 2012 - Mallory Przybylski
Reference: Chin, KJ, Wong, NWY, Macfarlane, AJR, and Chan, VWS. Regional Anesthesia and Pain Medicine 36(6): 611-618, 2011
Scientific Literature Review
Reviewed by: Mallory Przybylski, DPM
Residency Program: Yale-New Haven Hospital/ VACT
Podiatric Relevance:
The ankle block is an essential skill developed by the podiatric surgeon to obtain anesthesia and post-operative analgesia. Most surgeons choose to perform this block by using anatomic landmarks, however, there is an indication for the ultrasound-guided technique (USG). Many surgeons believe the anatomic landmark-guided (ALG) technique is difficult and provides unreliable results.
Methods:
The authors performed a retrospective cohort study over a six-year period and compared intra-operative and post-operative outcomes of ankle blocks performed for foot surgery via the ALG (n=128 patients) versus the USG technique (n=527 patients).
Results:
Patients receiving unilateral ankle blocks had more successful anesthesia in the USG group versus the ALG group (84 percent vs 66 percent, P<0.001). Patients in the ALG group more often required additional local anesthesia (10 percent vs 5 percent, P = 0.04), transition to general anesthesia (17 percent vs 7 percent, P = 0.001), or additional fentanyl (18 percent vs 9 percent, P= 0.002). Patients in the ALG group were also more likely to receive intravenous opioids (21 percent vs 12 percent, P= 0.01) and at higher doses than the USG group (10.6mg vs 8.7mg IV morphine, P= 0.022). In the bilateral ankle block group, successful surgical anesthesia was again more common in the USG group versus the ALG group (84 percent vs 57 percent), although the results were not statistically significant.
Conclusions:
This study demonstrated that an ankle block performed with USG versus ALG technique provided a more successful block, reduced the amount of supplemental local anesthetic, reduced the incidence of conversion to general anesthesia, and decreased the amount of post-operative analgesic required.