Combination Lower Extremity Nerve Blocks and Their Effect on Postoperative Pain and Opioid Consumption: A Systematic Review.

The purpose of this study was to perform a systematic review of the literature examining postoperative outcomes following single site and combined peripheral nerve blocks (PNBs), including (1) sciatic and femoral nerve, (2) popliteal and saphenous nerve, and (3) popliteal and ankle nerve, during elective foot and ankle surgery. We hypothesized that combination blocks would decrease postoperative narcotic consumption and afford more effective postoperative pain control as compared to general anesthesia, spinal anesthesia, or single site PNBs. A review of the literature was performed according to the PRISMA guidelines. Medline, EMBASE, and the Cochrane Library were searched from January 2009 to October 2019. We identified studies by using synonyms for "foot," "ankle" "pain management," "opioid," and "nerve block." Included articles explicitly focused on elective foot and ankle procedures performed under general anesthesia, spinal anesthesia, PNB, or with some combination of these techniques. PNB techniques included femoral, adductor canal, sciatic, popliteal, saphenous, and ankle blocks, as well as blocks that combined multiple anatomic sites. Outcomes measured included postoperative narcotic consumption as well as patient-reported efficacy of pain control. Twenty-eight studies encompassing 6703 patients were included. Of the included studies, 57% were randomized controlled trials, 18% were prospective comparison studies, and 25% were retrospective comparison studies. Postoperative opioid consumption and postoperative pain levels were reduced over the first 24 to 48 hours with the use of combined PNBs when compared with single site PNBs, both when used as primary anesthesia or when used in concert with general anesthesia either alone or combined with systemic/local anesthesia in the first 24 to 48 hours following surgery. Studies demonstrated higher reported patient satisfaction of postoperative pain control in patients who received combined PNB. Nine of 14 (64%) studies reported no neurologic related complications with an overall reported rate among all studies ranging from 0% to 41%. Our study identified substantial improvement in postoperative pain levels, postoperative opioid consumption, and patient satisfaction in patients receiving PNB when compared with patients who did not receive PNB. Published data also demonstrated that combination PNB are more effective than single-site PNB for all data points. Notably, the addition of a femoral nerve block to a popliteal nerve block during use of a thigh tourniquet, as well as addition of either saphenous or ankle blockade to popliteal nerve block during use of calf tourniquet, may increase overall block effectiveness. Serious complications including neurologic damage following PNB administration are rare but do exist.