Femoral Nerve, 3-in-1, and Fascia Iliaca Compartment Blocks

Specific femoral nerve blocks are performed with the patient lying supine. The ipsilateral limb preferably

Figure 45-11 Lumbar plexus nerve blocks: specific femoral nerve block (A), fascia iliaca compartment block (B), and "3-in-1" bloc (C), indicating the psoas muscle (1), lateral cutaneous nerve of the thigh (2), fascia iliaca (3), femoral nerve (4), femoral vessel sheath (5), fascia lata (6), division branches of the obturator nerve (7), femoral cutaneous posterior muscle (8), and sciatic nerve (9).

The 3-in-1 block was the first reported multiply effective technique.^[238] It consists of injecting the local anesthetic within the femoral nerve sheath and forcing it cephalad with the aim of reaching the lumbar plexus within its psoas compartment. The technique is basically the same as that of the classic femoral nerve block, but instead of being inserted vertically, the needle is advanced rostrally at a 30-degree angle (or less) to the skin until paresthesias or muscle twitches are elicited in the thigh. Firm finger pressure is then applied distal to the site of injection on the femoral artery before injecting the local anesthetic. This compression is maintained for several minutes while the swollen area is massaged to favor upward diffusion of the local anesthetic. The procedure results in constant femoral nerve block, and the lateral

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Using the fascia iliaca compartment block technique,^{[239] [240]} a local anesthetic is injected immediately below the fascia iliaca, favoring its spread at the inner surface of this fascia to make contact with the nerves emerging from the lumbar plexus that supply the lower extremity. The patient is placed in the supine position, and the skin projection of the inguinal ligament, extending from the anterior superior iliac spine to the pubic spine, is divided in three equal parts. The site of puncture is 0.5 to 1 cm below the union of the lateral one third with the medial two thirds, which is at least 2 to 3 cm lateral to the femoral artery ( Fig. 45-11 ). The (noninsulated) needle is connected by an extension line to the syringe filled with the local anesthetic and is inserted at right angles to the skin while gentle pressure is exerted on the barrel. Two resistances followed by LOR are sought. The first one occurs as the tip of the needle crosses the fascia lata, and the second one occurs as the fascia iliaca is pierced; the injection is made at the second level. Injecting a sufficient volume and massaging the swollen area favor the spread of solution to the inner surface of the fascia iliaca, improving the chances to block distant lumbar plexus nerves such as the obturator nerve. With this technique, the femoral and lateral cutaneous nerves are almost always blocked, and the obturator nerve is reached in more than 75% of patients. The anesthetized area also includes areas supplied by upper branches of the lumbar plexus, such as the genitofemoral nerve, in more than 70% of procedures. Standard doses of local anesthetic are displayed in Table 45-11 . Addition of clonidine (see Table 45-3 ) improves the intensity and the duration of blockade. Placement of a catheter is easy and allows long-lasting pain relief (see Table 45-12 ). Whether a single injection or a continuous infusion of local anesthetic is performed, peak plasma concentrations of local anesthetic (especially bupivacaine) are within a safe range.^{[14] [76]}