Original contributionNerve stimulator versus ultrasound guidance for placement of popliteal catheters for foot and ankle surgery☆,☆☆
Introduction
Continuous perineural analgesia of the sciatic nerve via the popliteal fossa offers significant benefits after major foot and ankle surgery. Previous randomized controlled trials (RCTs) have shown that continuous popliteal block versus either placebo or intravenous (IV) patient-controlled analgesia (PCA) opioids results in markedly improved postoperative analgesia, decreased opioid use, decreased opioid-related side effects, greater patient satisfaction, and greater short-term functional activity [1], [2].
Currently, popliteal catheters are commonly inserted after initial localization with a nerve stimulator-guided needle [3]. Thus, precise location of the needle and catheter cannot be ascertained. Ultrasound guidance has gained popularity for regional anesthesia as it allows precise localization of neural targets and needle placement. A recent systematic review of ultrasound guidance for regional anesthesia noted that ultrasound versus nerve stimulator for lower-extremity, single-shot nerve blocks, including popliteal blocks, improved the quality and onset of anesthesia [4]. Thus, ultrasound guidance may improve the quality of continuous popliteal block when compared with a similar block by nerve stimulator. However, only a single RCT has compared the nerve stimulator with ultrasound guidance for placement of continuous popliteal block catheter, and that study primarily was interested in the time required for catheter placement [5]. We performed this prospective, randomized, double-blinded study to compare nerve stimulator with ultrasound guidance for postoperative analgesia after major foot and ankle surgery.
Section snippets
Materials and methods
After Hospital for Special Surgery Institutional Review Board approval and written, informed consent were obtained, patients undergoing major foot/ankle surgery with a planned hospital stay of more than 48 hours and requiring a perineural sciatic nerve catheter were enrolled. Exclusion criteria included neurological deficit in the operative extremity; infection at the site for the block; allergy to local anesthetics; pregnancy; diabetes; history of chronic opioid use; or ASA physical status
Results
Fig. 1 displays the CONSORT (Consolidated Standards of Reporting Trials) flow of patients through the study. After randomization, 6 patients (4 in the nerve stimulator and two in the ultrasound group) were excluded due to protocol violations (eg, PCA pump misprogramming or malfunction, incorrect bolus dose, or infusion adjustments). Patient characteristics and types of surgical procedures were similar between groups (Table 1). All patients had successful sensory block to cold in the sciatic
Discussion
The use of ultrasound markedly decreased consumption of local anesthetic, which suggests that ultrasound allowed closer approximation of the popliteal catheter than did nerve stimulator guidance. Several RCTs also noted greater efficacy for ultrasound versus nerve stimulator guidance for single-shot popliteal block with either significantly faster onset or success rates [8], [9], [10], [11]. Thus, it is likely that ultrasound allowed superior targeting of the block needle so that subsequent
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Cited by (0)
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No author has financial interests to disclose.
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Funding: Hospital for Special Surgery's Anesthesiology Department Research and Education Fund.