Medial Branch Block and Radiofrequency Lesioning

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Chapter 8 Medial Branch Block and Radiofrequency Lesioning

Yong-Chul Kim, MD, PhD

Medial branch block (MBB) and radiofrequency lesioning yield good results both after failure of conservative treatment in patients with mechanical back pain and in patients with failed back surgery syndrome. The complications of these procedures are usually minor and transient, and the complication rates are low.

Treatment objectives

Medial Branch Block

The treatment objectives are to diagnose and treat facet joint syndrome. Facet joints are one of the most common sources of back pain. Facet joint syndrome cannot be diagnosed clinically or radiographically but can be identified with MBB or facet joint injection [1–5]. A series (3-5 times) of local anesthetic injections with or without corticosteroids sometimes achieves long-term relief of back pain.

Radiofrequency Neuromodulation (Pulsed Radiofrequency Lesioning) or Neuroablation (Radiofrequency Thermocoagulation) of the Medial Branch

The treatment objective of radiofrequency lesioning is to treat facet joint syndrome. This procedure offers pain relief by modulating (pulsed radiofrequency lesioning [PRFL]) or denaturing (radiofrequency thermocoagulation [RFTC]) medial branches that innervate the painful facet joints. The typical durations of pain relief experienced after such procedures are as follows [6]:

image Initial radiofrequency procedure: 223-730 days
image Repeat radiofrequency procedure: 144-478 days

Preoperative preparation

History Taking and Physical Examination

The symptoms and signs that should be sought during history taking and on physical examination include the following:

image Pain aggravation on hyperextension and rotation of spine and alleviation on spine flexion
image Local deep tenderness over the facet joint(s)
image Limitation of motion
image Referred pain (Figs. 8-6 to 8-9)
image

Figure 8–6 Patterns of pain (shaded areas) evoked by stimulation of the facet joints at segments C2-C3 to C6-C7.

(Adapted from Dwyer A, Aprill C, Bogduk N: Cervical zygapophyseal joint pain patterns: I: A study in normal volunteers. Spine 1990;15:453-457.)

image

Figure 8–7 A composite map shows pain referral patterns from the T3-T4 to the T10-T11 thoracic facet joints.

(Modified from Dreyfuss P, Tibiletti C, Dreyer S: Thoracic zygapophyseal joint pain patterns. Spine 1994:19;807-811.)

image

Figure 8–8 A composite map shows pain referral patterns at the C7-T1, T1-T2, T2-T3, and T11-T12 thoracic facet joints.

(Modified from Fukui S, Ohseto K, Shiotani M: Patterns of pain induced by distending the thoracic zygapophyseal joints. Reg Anesth 1997:22;332-336.)

image

Figure 8–9 A schematic drawing shows the referred pain pattern for the lumbar facet joints.

(Modified from Bous RA: Facet joint injections. In Stanton-Hicks M, Bous RA [eds]: Chronic Low Back Pain. New York, Raven, 1982, pp 199-211.)

Imaging Diagnosis

The following imaging modalities are used to identify surgical candidates:

image Plain radiography (Fig. 8-1)
image Bone scanning (Fig. 8-2)
image Computed tomography (CT) (Fig. 8-3)
image Magnetic resonance imaging (MRI) (Figs. 8-4 and 8-5)
image image

Figure 8–1 Radiographic findings in facet osteoarthritis. Note the foraminal stenosis due to the osteophyte from facet joint (arrow ) in A and the facet joint space narrowing and subchondral sclerosis (yellow arrows ) in B.

image

Figure 8–2 Bone scan findings in facet osteoarthritis. High radiotracer uptake can be seen at multiple facet joints (arrows) on the posterior image (right ), whereas relatively low uptake is shown on the anterior image (left ).

image

Figure 8–3 Computed tomography findings in facet osteoarthritis. Note the osteophyte (white arrows ), vacuum change (red arrow ), and subchondral sclerosis.

image

Figure 8–4 Magnetic resonance imaging features of the facet joints. Note that the gradient-echo image (B) shows more detail of the facet joint structure than the spin-echo image (A).

image

Figure 8–5 Magnetic resonance imaging findings in facet osteoarthritis. A, Spin-echo T1-weighted image; B, spin-echo T2-weighted image; C, gradient-echo T2-weighted image. Note the geode appearance (yellow dotted circle), effusion (red arrow), subchondral cyst (blue dotted circle), joint space narrowing (white arrows), subchondral sclerosis (yellow arrow), and osteophyte (black arrows).

Indications

Medial Branch Block

Indications for MBB in the cervical spine include the following:

image Local tenderness over the cervical facet joints
image Pain aggravation upon hyperextension or rotation of the neck
image Referred pain (Fig. 8-6)
image Decrease in or absence of cervical mobility
image No objective neurologic signs
image Radiologic signs of facet osteoarthritis

Indications for MBB in the thoracic spine include the following:

image Paravertebral pain and tenderness over the thoracic facet joints
image Referred pain (Figs. 8-7 and 8-8)
image Pain aggravation on hyperextension and rotation and in the sitting position
image No objective neurologic signs
image Radiologic signs such as severe kyphoscoliosis, osteoporosis, vertebral compression fracture, and facet osteoarthritis

Indications for MBB in the lumbar spine include the following:

image Paravertebral pain and tenderness over the lumbar facet joints
image Referred pain (Fig. 8-9)
image Decrease or absence of mobility in the painful region of the back
image Pain aggravation on hyperextension and rotation and in the sitting position
image No objective neurologic signs
image Radiologic signs such as severe scoliosis, osteoporosis, vertebral compression fracture, and facet osteoarthritis

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch

Indications for PRFL or RFTC in any area of the spine are as follows:

image Response to the diagnostic MBB is positive.
image A series of MBBs (3 to 5 times at 2-week intervals) with local anesthetics and steroids show significant relief of pain, but its effect does not persist more than 6 months.

Contraindications

Contraindications to MBB, PRFL, and RFTC are as follows:

image Patient’s refusal
image Skin infection over the puncture site or systemic infection
image Coagulopathy (International Normalized Ratio [INR] value > 1.5 or platelet count < 50,000/mm3) or anticoagulant therapy

In terms of the third contraindication, if anticoagulant therapy can be suspended temporarily, the patient should stop taking the medication 3 to 7 days before the procedure and resume 3 to 7 days after it. In the patient in whom anticoagulant therapy cannot be stopped temporarily and who is to undergo MBB, a 26-gauge block needle should be used and an ice pack should be applied for 10 minutes immediately after the procedure; in the patient undergoing RF lesioning, an ice pack should be applied for 10 minutes immediately after the procedure and a compression dressing should be used.

Complications

Medial Branch Block

Complications of MBB are usually minor and are resolved within a couple of days of the procedure; they include the following:

image Pain associated with the procedure
image Accidental spinal cord or nerve root injury, especially at the cervical region (Fig. 8-19)
image Infection
image Hematoma
image

Figure 8–19 Radiofrequency lesioning of the third occipital nerve with the rotating curved needle technique. The white line indicates the radiofrequency cannula and the yellow dotted lines indicate the tip positions of the curved cannula when it is rotated cephalad or caudad (arrows). With the rotating curved needle technique, a large lesion can be obtained easily within few minutes.

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch [7]

Complications of PFRL and RFTC are usually minor and are resolved in a short time (<1 month) after the procedure [7]. They include the following:

image Postprocedural pain usually lasting for 1-16 days
image Numbness or dysesthesia in the cutaneous territory of the coagulated nerves (in 42% of cases)
image Psoriatic rash at the skin puncture site (Köbner phenomenon) (8%)
image Failure to control pain (25%)
image Infection
image Hematoma
image Ataxia, especially at the third occipital nerve
image Accidental spinal cord or nerve root injury, especially at the cervical region
image Pneumothorax at thoracic region

Anatomy

At each level, facet joint innervation is derived from the medial branch of the adjacent spinal nerve, as well as the medial branches located one level above and perhaps one level below. Figures 8-10 through 8-12 show facet joint innervation of the three regions of the spine.

image

Figure 8–10 Lateral radiograph of the cervical dorsal rami. The third occipital nerve (TON) crosses the inferior pole of the C2-C3 zygapophyseal joint, running close to the C3 deep medial branch (C3 MB-2). The C4 through C6 medial branches course around the waists of the articular pillars. The C7 medial branch crosses the root of the C7 transverse process and therefore lies higher on the lateral projection of the C7 articular pillar. GON, greater occipital nerve.

image

Figure 8–11 An illustration of the medial branches of the thoracic dorsal rami viewed from behind. T1 through T4, T9, and T10 medial branches typically cross the superolateral corners of the transverse processes. T5 through T8 medial branches show an atypical course that sometimes appears to be suspended in the intertransverse space. T11 and T12 medial branches assume a course analogous to that of the lumbar medial branches, crossing the junction of the superior articular process and the base of the transverse process. C7, seventh cervical vertebra; L1, first lumbar vertebra; LB, lateral branch; MB, medial branch; TP, transverse process.

(Modified from Chua WH, Bogduk N: The surgical anatomy of thoracic facet denervation. Acta Neurochir [Wien] 1995;136:140-144.)

image

Figure 8–12 An illustration of the right posterior oblique view of the lumbar spine from L2 to L5. Each of the L1 through L4 medial branches crosses the junction of the superior articular process (S) and the base of the transverse process. The L5 dorsal rami cross the junction of the superior articular processes and the ala of the sacrum. DPR3, L3 dorsal primary ramus; I, inferior articular process; NR2, L2 nerve root.

Instruments and solutions

Medial Branch Block

The instruments (Fig. 8-13) and solutions used in MBB are as follows:

image 26-gauge, 1.5-inch and 3.5-inch needles for skin infiltration
image 22-gauge, 3.5-inch spinal needle
image 1-mL, 2-mL, and 10-mL syringes
Solutions: 2% lidocaine or 0.5% levobupivacaine (Chirocaine), water-soluble contrast agent with or without steroids.
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