NYSORA 4 U (N4U): What’s New
Does Adductor Canal Block Affect Sciatic Nerve Branches?
Mid-thigh and distal adductor canal block techniques, both low and high volume, are frequently used in knee surgeries to contain injectate within the canal. However, there is a risk of spillage into the popliteal fossa, which could affect analgesia and lead to a motor block due to sciatic nerve coverage. This radiological cadaveric study examined the incidence of coverage of sciatic nerve divisions after various adductor canal block techniques. Using 18 fresh cadavers, injections were administered with 2 mL or 30 mL injectate volumes on both sides (36 injections in total), and spread was assessed via whole-body CT scans. Results revealed no sciatic nerve coverage, with contrast reaching the popliteal fossa in only three cases. While saphenous nerve coverage was consistent, the femoral nerve remained unaffected. Thus, adductor canal block techniques are unlikely to affect the sciatic nerve, but the clinical analgesic impact of popliteal fossa spread remains uncertain.
Axial CT imagery presenting typical injectate spread patterns after low (left) and high (right) volume distal adductor block. Solid arrows point to contrast, whereas dotted arrows indicate specific nerves. PN, common peroneal nerve; SCN, sciatic nerve; SN, saphenous nerve; TN, tibial nerve.
To read the full paper in RAPM, copy-paste this into your Google search:
Smulders PS, Ten Hoope W, Baumann HM, et al. Adductor canal block techniques do not lead to involvement of sciatic nerve branches: a radiological cadaveric study. Reg Anesth Pain Med. 2024;49(3):174-178.
