Skip to Main Content

++

  • Indications: foot and ankle surgery; analgesia following knee surgery
  • Transducer position: transverse on the lateral aspect of thigh or over popliteal fossa
  • Goal: local anesthetic spread surrounding the sciatic nerve within epineural sheath
  • Local anesthetic: 20–30 mL

++
Figure 40-1.
Graphic Jump Location

Cross-sectional anatomy of the sciatic nerve in the popliteal fossa. Shown are common peroneal nerve (CPN), tibial nerve (TN), popliteal artery (PA), popliteal vein (PV), femur, biceps femoris (BFM), semimembranosus (SmM) and semitendinosus (StM) muscles.

++

Performance of a sciatic block above the popliteal fossa benefits from ultrasound guidance in several ways. The anatomy of the sciatic nerve as it approaches the popliteal fossa can be variable, and the division into the tibial nerve (TN) and common peroneal nerve (CPN) occurs at a variable distance from the crease. Knowledge of the location of the TPN and CPN in relation to each other is beneficial in ensuring the anesthesia of both divisions of the sciatic nerve. Moreover, with nerve stimulator–based techniques, larger volumes (e.g., >40 mL) of local anesthetic often are required to increase the chance of block success and rapid onset. A reduction in local anesthetic volume can be achieved with ultrasound guidance because the injection can be halted once adequate spread is documented. The two approaches to the popliteal sciatic block common in our practice are the lateral approach with patient in supine (more commonly, oblique position) and the posterior approach (Figure 40-2). It should be noted that with the lateral approach, the resulting ultrasound image is identical to the image in the posterior approach. Both are discussed in this chapter. Only the patient position and needle path differ between the two approaches; the rest of the technique details

++
Figure 40-2.
Graphic Jump LocationGraphic Jump Location

Posterior approach to ultrasound-guided popliteal sciatic block can be performed with the patient in the oblique position (A) or with the patient prone (B).

++

With the posterior and the lateral approaches, the transducer position is identical; thus the sonographic anatomy appears the same. However, note that although the image appears the same, there is a 180° difference in patient orientation. Beginning with the transducer in the transverse position at the popliteal crease, the popliteal artery is identified, aided with the color Doppler ultrasound when necessary, at a depth of approximately 3 to 4 cm. The popliteal vein accompanies the artery. On either side of the artery are the biceps femoris muscles (lateral) and the semimembranosus and semitendinosus muscles (medial). Superficial (i.e., toward the skin surface) and lateral to the artery is the tibial nerve, seen as a hyperechoic, oval, or round structure with a stippled or honeycomb pattern on the interior (Figure 40-3A and B). If difficulty in identifying the nerve ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.