Brown single-needle technique

With this technique, the patient is placed in the prone position, and pillow support is provided. The needle is inserted 12.5 cm lateral to the spine at the level of the L4 vertebra, 1 cm cephalad to the ileum. A 22-gauge 14-cm needle is inserted at an angle of 35 to 40 degrees to the skin. The needle is directed medially until bone is contacted, and the needle lies at the anterolateral surface of the vertebra. The patient is then placed in a 5- to 140-degree Trendelenburg position, and 20 mL of local anesthetic agent is injected; the anesthetic agent should spread as high as L2. This oblique approach with insertion of the needle at the level of L4, versus a more cephalad position, is mandatory to avoid kidney injury. The Brown single-needle technique is infrequently used.

Lateral approach first described by reid

With this technique, the patient is again placed in the prone position with pillow support of the lower abdomen. Fluoroscopy is used for assistance in properly placing the needle. The spinous processes of L2, L3, and L4 are marked, and a site that is 7 to 8 cm lateral to midline at approximately the L2 to L3 transition is located. A spot that is perpendicular to the caudal aspect of the L2 vertebra, which corresponds to the interspace between the transverse process of L2 and L3, is marked. Reid described 7 cm as the optimal position to gain the proper trajectory to the ganglion of the vertebral body and to avoid injury to the renal parenchyma. This technique can be employed with a single needle at L3 or with as many as three needles positioned at L2, L3, and L4.

A 22-gauge 12-cm to 18-cm needle is advanced until it contacts the vertebral body at the cephalad portion of L3. The typical angle of insertion is 45 degrees, but this angle may be modified depending upon the patient’s body habitus. If bone is encountered soon after inserting the needle, the clinician has likely come into contact with a transverse process, and the needle trajectory should be modified cephalad or caudad to avoid contact with bone. If this occurs, the needle depth is noted, and the needle is retracted to skin level and redirected at a steeper angle under fluoroscopy to clear the lateral margin of the vertebra and position the tip at the anterolateral border of the vertebral body (Figure 219-1). The needle should be anterior to the psoas fascia. The needle is aspirated to verify extravascular position, taking into account the proximity of the aorta and vena cava. A small volume of iodinated contrast agent is injected, and spread should ideally be seen from L2 to L4. If spread is limited, additional needles can be placed at L2 and L4. Obtaining anteroposterior and lateral radiographic views helps to assess contrast spread, and, if striations (psoas stripe) are seen on fluoroscopy, the needle position may be too posterior.

It is helpful to initially inject 10 to 15 mL of lidocaine to document distal temperature rise and then follow with an additional 10 to 15 mL of bupivacaine. If temperature rise is not seen with initial injection, the needle should be repositioned and the local anesthetic agent reinjected, taking care to not exceed the maximum recommended dose of local anesthetic agent. The patient should be carefully monitored for the presence of lower extremity weakness and toxicity from the local anesthetic agent.

Mandl technique

With the Mandl technique, the spinous processes of L2 to L4 are marked, and a skin wheal is placed approximately 10 cm off midline with a local anesthetic agent injected at the L2 level and infiltrated to the transverse process. A 20-gauge, 12-cm needle is inserted to the level of the transverse process and then redirected medially toward the vertebral body 45 degrees to the coronal plane between the transverse processes. The needle is advanced, with the bevel toward the vertebral body, until contact is made; the needle is then adjusted to a position that allows it to slide 1 cm off the vertebral body. The position can be verified by loss of resistance and negative aspiration for cerebrospinal fluid, blood, or urine. Movement of the needle with normal respiration indicates lateral positioning in the diaphragmatic crus. Radiographic screening with contrast injection is recommended to ensure proper needle positioning, especially for neurolytic blocks. Alternatively, ultrasonography may be used, sparing the patient and physician radiation exposure. The procedure is repeated at the L4 level. Catheters may be placed if an 18-gauge needle is used.