Ultrasound-guided lumbar paravertebral nerve block is utilized in a variety of clinical scenarios as a diagnostic, prognostic, and therapeutic maneuver as well as to provide postoperative pain relief for lower abdominal, lower back, and groin surgeries. As a diagnostic tool, ultrasound-guided lumbar paravertebral block allows accurate placement of the needle tip within the lumbar paravertebral space when performing differential neural blockade on an anatomic basis in the evaluation of lower abdominal, lower back, and groin pain. As a prognostic tool, ultrasound-guided lumbar paravertebral block can be utilized as a prognostic indicator of the degree of motor and sensory impairment that the patient may experience if lumbar nerve roots are going to be destroyed in an effort to palliate intractable pain in patients too sick to undergo neurosurgical destructive procedures. In the acute pain setting, ultrasound-guided lumbar paravertebral block with local anesthetics may be used to palliate acute pain emergencies while waiting for pharmacologic, surgical, and/or antiblastic methods to become effective. This technique has great clinical utility in both children and adults when managing acute postoperative and posttrauma pain. Sympathetically mediated pain syndromes including the pain of acute herpes zoster of the lumbar dermatomes, lumbar vertebral compression fracture, and groin pain can also be effectively managed with local anesthetics and or steroids administered into the lumbar paravertebral space (Fig. 103.1). Pain of malignant origin of the lower chest wall, lower back, and groin as well as spinal metastatic disease (especially from breast and prostate primary cancers) is also amenable to treatment with local anesthetics and/or steroids and neurolytic agents such as phenol administered into the lumbar paravertebral space.

The lumbar paravertebral nerves exit their respective intervertebral foramina just beneath the transverse process of the vertebra (Fig. 103.2). After exiting the intervertebral foramen, the lumbar paravertebral nerve gives off a recurrent branch that loops back through the foramen to provide innervation to the spinal ligaments, meninges, and its respective vertebra. Passing through the lumbar paravertebral space, the lumbar paravertebral nerve then divides into posterior and anterior primary divisions (Fig. 103.3). The posterior division courses posteriorly and, along with its branches, provides innervation to the facet joints and the muscles and skin of the back (see Fig. 103.2). The larger anterior division courses laterally and inferiorly to enter the body of the psoas muscle. Within the muscle, the first four lumbar paravertebral nerves join to form the lumbar plexus (Fig. 103.4). The lumbar plexus also receives a contribution from the 12th thoracic paravertebral nerve. The lumbar plexus provides innervation to the lower abdominal wall, groin, portions of the external genitalia, and portions of the lower extremity.

Ultrasound-guided thoracic paravertebral block can be carried out by placing the patient in the lateral decubitus position (Fig. 103.5). A syringe containing 5 mL of 0.5% preservativefree lidocaine is attached to a 22-gauge, 13-cm needle. The midline of the lumbar spine is identified by palpation, as is the iliac crest, and a line is drawn from each of these anatomic landmarks (see Fig. 103.6).