Patient Selection

CCPVB is indicated for anesthesia and postoperative analgesia after upper extremity surgery or for prolonged continuous catheter analgesia in other clinical settings involving the upper limb. It has recently proved to be valuable in the management of pain due to conditions such as lung tumors infiltrating the brachial plexus (Pancoast tumors) and complex regional pain syndromes. CCPVB is especially suitable for patients scheduled for major shoulder surgery when preservation of motor function is desirable. Because ultrasonography, nerve stimulation, and loss-of-resistance techniques may be used for placement of this block, it is well suited for postoperative placement or for placement in patients with painful upper extremity conditions, in whom motor activation by nerve stimulator may be poorly tolerated.

Pharmacologic Choice

An initial bolus of 20 to 30 mL of 0.5% bupivacaine, 0.5% to 0.75% ropivacaine, or 0.5% to 0.75% levobupivacaine is usually used. When used for postoperative analgesia, this is usually followed by a continuous infusion of a lower concentration of the same drug (i.e., 0.25% bupivacaine, 0.2% ropivacaine, or 0.25% levobupivacaine) at an infusion rate of 3 to 15 mL/hr with or without the addition of patient-controlled boluses. Local anesthetic systemic toxic blood levels should be avoided when selecting an infusion rate and method.

Anatomy

The brachial plexus is situated between the anterior and middle scalene muscles (Fig. 37-2). The phrenic nerve is anterior to the anterior scalene muscle and lateral to the superior cervical plexus. The vertebral artery and vein are situated anterior to the pars intervertebralis (articular column of the vertebrae) and typically travel through the transverse foramen in the center of the transverse processes of the first to sixth cervical vertebrae. The vertebral artery lies anterior to the interarticular parts of the vertebrae, so there is minimal risk of arterial injury with a posterior needle approach.

Figure 37-2. Cervical paravertebral block: cross-sectional view.

Position

The patient is positioned in either the sitting or the lateral decubitus position (the levator scapulae muscle is usually easier to identify if the patient is sitting, but effective sedation is easier when the patient is in the lateral decubitus position). The patient’s neck is slightly flexed forward. The anesthesiologist stands behind the patient.

Needle Puncture

After preparation of the skin with an appropriate disinfectant and placement of sterile drapes, local anesthetic infiltration of the skin and subcutaneous tissue is performed to the level of the pars intervertebralis (which is easily seen with ultrasonography) and along the intended catheter tunneling site. The transverse process of C6 is distinctly different from that of other cervical vertebrae on ultrasonography because of the larger anterior tubercle of Chassaignac.

Next, an insulated 17- or 18-gauge Tuohy needle is inserted at the apex of the “V” formed by the trapezius and levator scapulae muscles at the level of the sixth cervical vertebra (see Fig. 37-1). The negative lead of the nerve stimulator, set to a current of 1.5 to 3 mA, a frequency of 2 Hz, and a pulse width of 100 to 300 µsec, is attached to the needle. If the block is intended for the management of pain associated with shoulder surgery, the needle is advanced anteromedially and is angled approximately 30 degrees caudad, aiming toward the suprasternal notch or cricoid cartilage until the transverse process of C6 or the pars intervertebralis of C6 is encountered. If the block is intended for wrist or elbow surgery, the needle is directed toward C7. This block is readily performed with ultrasonographic guidance, which avoids bony contact. However, close proximity to the bone is necessary if a true root-level block is intended. If the needle is directed too far laterally, the procedure will become no different from a traditional interscalene block except that the needle approach is posterior and not lateral.

The stylet of the needle is removed after bone is encountered, and a loss-of-resistance syringe is attached to the needle. While continuously testing for loss of resistance, the needle is laterally “walked off” this bony structure and advanced anteriorly. Its course may be followed with ultrasonography, if available. Usually a distinct loss of resistance to air occurs simultaneously with a motor response observed in the biceps muscle (C5-C6) as the cervical paravertebral space is entered approximately 0.5 to 1 cm beyond the transverse process. At this level, the motor (anterior) and sensory (posterior) fibers have joined to become the roots of the brachial plexus, and more current is typically required to elicit a motor response than with an anterior interscalene technique (Fig. 37-3). If more distal surgery is planned (i.e., elbow, wrist, or hand), it is necessary to place the needle (and catheter) on the C7-C8 root, and a triceps motor response should be sought.

Figure 37-3. Cervical paravertebral block: catheter insertion after stimulation.

Catheter Placement

When the tip of the needle nears the roots of the brachial plexus (indicated either by a motor response or by patient report of sensory pulsation at a nerve stimulator output setting of approximately 0.5 mA), the needle is held steady while the loss-of-resistance syringe is removed. If ultrasonography is being used, a few milliliters of 5% dextrose and water can be injected through the needle to confirm correct needle placement. The nerve stimulator lead is now attached to the proximal end of a 19- or 20-gauge stimulating catheter and its distal end is inserted into the needle shaft. If a nonstimulating technique is used, a bolus injection is performed through the needle followed by advancement of a standard epidural catheter, but the stimulation technique is highly recommended for all needle placements because it clearly indicates the specific nerve root being blocked. For example, a C5-C6 block will be of minimal value for wrist or elbow surgery, whereas a C7-C8 root block will be of limited value for shoulder surgery.

As the stimulating catheter is advanced, nerve stimulator output should be kept constant at a current that provides brisk muscle twitches of the shoulder or upper extremity muscles but is not uncomfortable to the patient. The catheter tip should be advanced 3 to 5 cm beyond the tip of the needle, as described in Chapter 2, Continuous Peripheral Nerve Blocks. After catheter advancement, the catheter is tunneled approximately 5 cm away from the insertion site to a convenient position and covered with a transparent dressing.

Patient Selection

This block is effective for superficial surgical procedures of the chest wall (e.g., mastectomy), insertion of chest tubes, and analgesia after thoracotomy or rib fractures. It may also be performed through a catheter to produce prolonged analgesia after unilateral thoracic surgery, such as thoracotomy or unilateral upper abdominal surgery (e.g., nephrectomy or rib fractures). This block is especially indicated for patients with unilateral or bilateral pain when avoidance of hypotension related to the sympathectomy often associated with epidural block is desirable. However, hypotension may still occur with epidural spread in patients receiving larger volumes of local anesthetic in the paravertebral space.

Pharmacologic Choice

The total volume of local anesthetic injected should be considered. Each level injected with the single-injection technique requires 5 mL of local anesthetic; total volumes can easily range from 30 mL with unilateral injections to 60 mL with bilateral injections. A continuous infusion of a lower concentration of the same drug at 5 to 15 mL/hr is commonly used for continuous analgesia. Any of the amino amide local anesthetics can be used for single-injection blocks or continuous infusions.

Anatomy

Figure 37-4 identifies the nerves in the thoracic paravertebral region that are anesthetized after injection of local anesthetic in the paravertebral space. The paravertebral space is immediately anterior to the transverse process and is bordered medially by the pedicle and vertebral body, anteriorly by the costovertebral joint, laterally by the rib and costotransverse joint, and posteriorly by the costotransverse ligament and transverse process. The endothoracic fascia bisects this space.

Figure 37-4. Thoracic paravertebral block: cross-sectional view.

Position

The patient can be placed in the lateral or sitting position for this procedure. The anesthesiologist stands behind the patient in a position similar to that for a thoracic epidural insertion.

Needle Puncture

The midline of the back is identified, and the thoracic levels to be blocked are identified. A point 2 to 2.5 cm lateral to the midline and at the level of the superior border of the vertebral spinous process is marked at each level (Fig. 37-5). It is important not to choose an entry point too far lateral to minimize needle entry into the pleural cavity. The skin overlying the proposed needle insertion sites is cleaned with an appropriate disinfectant. Local anesthesia of the skin and subcutaneous tissues is produced using 1% lidocaine.

Figure 37-5. Thoracic paravertebral block: landmarks for block.

An 18-gauge Tuohy needle attached to a loss-of-resistance syringe is advanced anteriorly and slightly medially toward the transverse process. The transverse process can easily be identified on ultrasonography and the needle can be followed in-plane or out-of-plane until it contacts the transverse process, usually 3 to 5 cm from the skin in most patients. After the needle contacts the transverse process and the depth is marked, the needle should be withdrawn, redirected slightly caudad and laterally, and advanced 1 to 1.5 cm deeper than the depth at which the transverse process was encountered. Using a needle with 1-cm markings along the shaft facilitates placement, but this advancement can also be guided by ultrasonography. It is important not to advance more than 1 to 1.5 cm beyond the transverse process to limit entry into the pleural space (see Fig. 37-5). Entry of the needle into the paravertebral space should be associated with a typical loss of resistance to air (or 5% dextrose in water) as the needle penetrates the costotransverse ligament. Aspiration for air, blood, or cerebrospinal fluid should be negative, and the subsequent injection should flow easily. A total volume of 5 mL of local anesthetic is injected at each level.

A catheter can be placed through the needle using the same procedure previously described for CCPVB. Nerve stimulation for catheter placement is useful but not essential for this block. If the catheter feeds too easily, it may be an indication of intrapleural catheter placement. More than one catheter may be required if the pain originates from multiple sites, such as multiple unilateral rib fractures, thoracotomy with placement of a chest tube, and bilateral surgery or trauma.

Patient Selection

This block is indicated for postoperative analgesia after lower limb surgery and trauma involving the hip or thigh. Its most common use is for pain associated with hip arthroplasty, but procedures like surgery to the femur and acetabulum of the hip are also appropriate indications. This block is typically used when it is not practical or possible to place a femoral nerve block.

Pharmacologic Choice

When selecting a local anesthetic, the degree of motor and sensory block desired must be considered, taking into account that a total of 20 to 40 mL of local anesthetic is suggested for the block and that this block may need to be combined with an additional block of the sciatic nerve. A continuous infusion of a lower concentration of a long-acting local anesthetic drug at 5 to 15 mL/hr is commonly used for continuous analgesia. Any of the amino amide local anesthetics can be used effectively for single-injection blocks or continuous infusions.

Anatomy

The nerves of the lumbar plexus are anesthetized by injecting a local anesthetic solution near the lumbar plexus, which is situated in the psoas compartment, anterior to the transverse process of the lumbar vertebral body (Fig. 37-6).

Figure 37-6. Lumbar paravertebral block: cross-sectional view.

Position

Patients are placed in the lateral decubitus position with the thighs flexed. Alternatively, they may be placed in the sitting or prone position. The anesthesiologist’s position is similar to that for a neuraxial puncture.

Needle Puncture

After the patient is positioned, a line is drawn between the superior margins of the iliac crests (i.e., Tuffier’s line). The vertebral spine palpable on this line in the midline is most often the fourth lumbar vertebra. The midline is marked and a second line, parallel to the midline, is drawn from the posterior superior iliac spine cephalad on the side being anesthetized. The needle insertion site is marked at a point on Tuffier’s line two thirds of the distance between the midline and the second, more laterally placed line originating from the posterior superior iliac spine (Fig. 37-7). Alternatively, the needle insertion site may be determined by identifying the L4-L5 interspace with ultrasonography. The skin overlying the proposed needle insertion site is then prepared aseptically and sterile drapes applied. The skin and subcutaneous tissues are anesthetized with 1% lidocaine.

Figure 37-7. Lumbar paravertebral block: landmarks for block.

An insulated 17- or 18-gauge needle is attached to a loss-of-resistance syringe, and a nerve stimulator is set to a current output of 1.5 mA, a frequency of 2 Hz, and a pulse width of 100 to 300 µsec. The needle is then advanced in a parasagittal or slightly medial fashion until it makes contact with the transverse process. The needle’s progress can be guided by ultrasonography. Bony contact typically occurs at a depth of 5 to 8 cm. The needle is then withdrawn and redirected caudad until it just slides past the transverse process. As the needle enters the psoas compartment, a loss of resistance will occur. Slightly deeper, and sometimes as much as 2 cm deeper, the lumbar plexus will be encountered and a motor response of the quadriceps muscle observed during nerve stimulation. If it is not observed immediately after the loss of resistance is encountered and the needle is advanced a maximum of 2 cm, it may require increased current or redirection of the needle.

After the lumbar plexus is identified, a total of 20 to 30 mL of the local anesthetic solution is injected in divided doses. Because the nerve roots are covered with a dura mater sleeve, this block and the other paravertebral blocks (cervical and thoracic) should be regarded as paraspinal (or paraneuraxial) epidural blocks and should be in many ways similar to spinal or neuraxial epidural blocks. A catheter may be placed through the needle using the same procedure previously described for CCPVB. Nerve stimulation for catheter placement is useful for this block.