Adductor canal nerve catheter for post-operative management of medial ankle pain following ankle fusion

The Importance of the Saphenous Nerve Block for Analgesia Following Major Ankle Surgery: A Randomized, Controlled, Double-Blind Study

BACKGROUND AND OBJECTIVES

Major ankle surgery causes intense postoperative pain, and whereas the importance of a sciatic nerve block is well established, the clinical significance of a supplemental saphenous nerve block has never been determined in a prospective, randomized, double-blind, placebo-controlled trial. We hypothesized that a saphenous nerve block reduces the proportion of patients experiencing significant clinical pain after major ankle surgery.

METHODS

Eighteen patients were enrolled and received a popliteal sciatic nerve block. Patients were randomized to single-injection saphenous nerve block with 10 mL 0.5% bupivacaine with 1:200,000 epinephrine or 10 mL saline (Fig. 1). Primary outcome was the proportion of patients reporting significant clinical pain, defined as a score greater than 3 on the numerical rating scale. Secondary outcomes were maximal pain and analgesia of the cutaneous territory of the infrapatellar branch of the saphenous nerve.

RESULTS

Eight of 9 patients in the placebo group reported significant clinical pain versus 1 of 9 patients in the bupivacaine-epinephrine group (P = 0.003). Maximal pain was significantly lower in the active compared with the placebo group (median, 0 [0-0] vs 5 [4-6]; P = 0.001). Breakthrough pain from the saphenous territory began within 30 minutes after surgery in all cases. Sensory testing of the cutaneous territory of the infrapatellar branch of the saphenous nerve showed correlation between pain reported in the anteromedial ankle region and the intensity of cutaneous sensory block in the anteromedial knee region.

CONCLUSIONS

The saphenous nerve is an important contributor to postoperative pain after major ankle surgery, with significant clinical pain appearing within 30 minutes after surgery.

CLINICAL TRIALS REGISTRATION

This study has been registered at ClinicalTrials.gov, identifier NCT02697955.

Effect of Perineural Dexamethasone on the Duration of Single Injection Saphenous Nerve Block for Analgesia After Major Ankle Surgery: A Randomized, Controlled Study

BACKGROUND AND OBJECTIVES

Patients undergoing major elective ankle surgery often experience pain from the saphenous nerve territory persisting beyond the duration of a single-injection saphenous nerve block. We hypothesized that perineural dexamethasone as an adjuvant for the saphenous nerve block prolongs the duration of analgesia and postpones as well as reduces opioid-requiring pain.

METHODS

Forty patients were included in this prospective, randomized, controlled study. All patients received a continuous sciatic catheter and were randomized to receive a single-injection saphenous nerve block with 10 mL of 0.5% bupivacaine with 1:200,000 epinephrine with addition of 1 mL of saline or 1 mL of 0.4% (ie, 4 mg) dexamethasone. The primary outcome was duration of saphenous nerve block estimated as the time until the first opioid request. Secondary outcomes were opioid consumption and pain.

RESULTS

The mean (SD) duration of the saphenous nerve block until first opioid request was 29.4 (8.4) hours in the dexamethasone group and 23.2 (10.3) hours in the control group (P = 0.048). The median opioid consumption [interquartile range] during the first 24 hours was 0 mg [0-0] versus 1.5 mg [0-14.2] in the dexamethasone and control groups, respectively. Nonparametric comparison of opioid consumption from 0 to 24 hours was statistically significant. The opioid consumption was similar in the two groups in the time interval 24 to 48 postoperative hours.

CONCLUSION

Perineural dexamethasone as an adjuvant for the single-injection subsartorial saphenous nerve block can prolong analgesia and reduce opioid-requiring pain after major ankle surgery.

Peripheral nerve blocks for ambulatory surgery

Peripheral nerve blocks (PNBs) provide significant improvement in postoperative analgesia and quality of recovery for ambulatory surgery. Use of continuous PNB techniques extend these benefits beyond the limited duration of single-injection PNBs. The use of ultrasound guidance has significantly improved the overall success, efficiency, and has contributed to the increased use of PNBs in the ambulatory setting. More recently, the use of ultrasound guidance has been demonstrated to decrease the risk of local anesthetic systemic toxicity. This article provides a broad overview of the indications and clinically useful aspects of the most commonly used upper and lower extremity PNBs in the ambulatory setting. Emphasis is placed on approaches that can be used for single-injection PNBs and continuous PNB techniques.