Sonography for Saphenous Nerve Block Near the Adductor Canal

Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco General Hospital, San Francisco, CA
Regional Anesthesia and Pain Medicine (Impact Factor: 3.09). 07/2007; 32(4):369-70. DOI: 10.1016/j.rapm.2007.04.006
Source: PubMed
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    • "The efficacy of the different techniques of the saphenous nerve block is variable depending on the type of the technique and the volume of the local anesthetic used. The success rate varies considerably in the literature: 80% with the transsartorial and perifemoral approaches, 40% with the below-the-knee field block[123] and 77% to 100% with ultrasound guidance at different anatomic areas above the knee.[456789101112] In addition, there was no previous study that examined the efficacy of the saphenous nerve block with a volume of 5 ml of local anesthetic within and distal to the adductor canal. "
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    ABSTRACT: Background and Aims: The anatomic site and the volume of local anesthetic needed for an ultrasound-guided saphenous nerve block differ in the literature. The purpose of this study was to examine the effect of two different ultrasound-guided low volume injections of local anesthetic on saphenous and vastus medialis nerves. Materials and Methods: Recruited patients (N = 48) scheduled for orthopedic surgery were randomized in two groups; Group distal adductor canal (DAC): Ultrasound-guided injection (5 ml of local anesthetic) distal to the inferior foramina of the adductor canal. Group adductor canal (AC): Ultrasound-guided injection (5 ml local anesthetic) within the adductor canal. Following the injection of local anesthetic, block progression was monitored in 5 min intervals for 15 min in the sartorial branches of the saphenous nerve and vastus medialis nerve. Results: Twenty two patients in each group completed the study. Complete block of the saphenous nerve was observed in 55% and 59% in Group AC and DAC, respectively (P = 0.88). The proportion of patients with vastus medialis weakness at 15 min in Group AC, 36%, was significantly higher than in Group DAC (0/22), (P = 0.021). Conclusions: Low volume of local anesthetic injected within the adductor canal or distally its inferior foramina leads to moderate success rate of the saphenous nerve block, while only the injection within the adductor canal may result in vastus medialis nerve motor block.
    Journal of Anaesthesiology Clinical Pharmacology 07/2014; 30(3):378-82. DOI:10.4103/0970-9185.137271
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    ABSTRACT: : During ankle block performance, anesthetizing the sural nerve is important for generating complete anesthesia of the lateral aspect of the foot. We hypothesized that an ultrasound-guided perivascular approach, utilizing the lesser saphenous vein as a reference, would prove more successful than a conventional approach based on surface landmarks. : Eighteen healthy volunteers were prospectively randomized into this controlled and blinded study. Each subject was placed prone and the right ankle was randomized to receive either an ultrasound-guided perivascular sural nerve block (group US) or a traditional landmark-based sural nerve block (group TRAD). The subject's left ankle then received the alternate approach. The ultrasound technique relied on injecting local anesthetic circumferentially around the lesser saphenous vein. All blocks were performed with 5 mL of 3% chloroprocaine. We evaluated sensory block to ice and pinprick. Secondary outcome variables included performance times, number of needle passes, participant satisfaction, and presence of any complications. : At the midfoot position, testing at 10 minutes after block placement revealed a loss of sensation to ice in 94% (complete in 78% and partial in 16%) in the US group versus 56% in the TRAD group (complete in 28%, partial in 28%) (P <.01). Complete loss of sensation to ice persisted in 33% of the US group as compared with 6% in the TRAD group at 60 minutes (P <.05). A similar pattern was observed when the blocks were tested with pinprick. Ultrasound-guided blocks took longer to perform on average than the traditional blocks (mean difference of 102 seconds, P <.001). The ultrasound block was subjectively felt to be denser by 88% of the subjects (P =.001). : Ultrasound guidance using the lesser saphenous vein as a reference point results in a more complete and longer lasting sural nerve block than does a traditional approach using surface landmarks.
    Regional anesthesia and pain medicine 01/2009; 34(1):24-8. DOI:10.1097/AAP.0b013e3181933f09 · 3.09 Impact Factor

  • Regional anesthesia and pain medicine 11/2009; 34(6):618-9. DOI:10.1097/AAP.0b013e3181bfbf00 · 3.09 Impact Factor
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