Medial Branch Block and Radiofrequency Lesioning

Published on 10/03/2015 by admin

Last modified 22/04/2025

Print this page

This article have been viewed 9424 times

Chapter 8 Medial Branch Block and Radiofrequency Lesioning

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]:

Initial radiofrequency procedure: 223-730 days

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:

Pain aggravation on hyperextension and rotation of spine and alleviation on spine flexion

Local deep tenderness over the facet joint(s)

Limitation of motion

Referred pain (Figs. 8-6 to 8-9)

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.)

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.)

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.)

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:

Plain radiography (Fig. 8-1)

Bone scanning (Fig. 8-2)

Computed tomography (CT) (Fig. 8-3)

Magnetic resonance imaging (MRI) (Figs. 8-4 and 8-5)

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.

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 ).

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

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).

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:

Local tenderness over the cervical facet joints

Pain aggravation upon hyperextension or rotation of the neck

Referred pain (Fig. 8-6)

Decrease in or absence of cervical mobility

No objective neurologic signs

Radiologic signs of facet osteoarthritis

Indications for MBB in the thoracic spine include the following:

Paravertebral pain and tenderness over the thoracic facet joints

Referred pain (Figs. 8-7 and 8-8)

Pain aggravation on hyperextension and rotation and in the sitting position

No objective neurologic signs

Radiologic signs such as severe kyphoscoliosis, osteoporosis, vertebral compression fracture, and facet osteoarthritis

Indications for MBB in the lumbar spine include the following:

Paravertebral pain and tenderness over the lumbar facet joints

Referred pain (Fig. 8-9)

Decrease or absence of mobility in the painful region of the back

Pain aggravation on hyperextension and rotation and in the sitting position

No objective neurologic signs

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:

Response to the diagnostic MBB is positive.

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:

Patient’s refusal

Skin infection over the puncture site or systemic infection

Coagulopathy (International Normalized Ratio [INR] value > 1.5 or platelet count < 50,000/mm ³) 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:

Pain associated with the procedure

Accidental spinal cord or nerve root injury, especially at the cervical region (Fig. 8-19)

Infection

Hematoma

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.

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.

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.

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.)

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:

26-gauge, 1.5-inch and 3.5-inch needles for skin infiltration

22-gauge, 3.5-inch spinal needle

1-mL, 2-mL, and 10-mL syringes

Solutions: 2% lidocaine or 0.5% levobupivacaine (Chirocaine), water-soluble contrast agent with or without steroids.

Figure 8–13 Instruments for medial branch block. Contrast agent is prepared in a 2-mL syringe with an extension tube. To avoid false-negative results of this block due to inadvertent vascular injection, continuous fluoroscopic guidance is applied during the injection of 0.2 mL of a contrast agent at each cervical segment.

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch

The following instruments and solutions are used in PRFL and RFTC:

A radiofrequency lesion generator, a connecting cable, and a probe (Fig. 8-14)

Radiofrequency cannulas: curved or straight (Fig. 8-15)

26-gauge, 1.5-inch and 3.5-inch skin infiltration needles

Local anesthetics

Figure 8–14 The RF Generator (A), along with its hand controller (B), self-grounded NiTRODE cannula and probe (C), and connecting cables (D), manufactured by Stryker Instruments, (Kalamazoo, MI). Product images from Stryker website, www.stryker.com.

Figure 8–15 Curved and straight SMK cannulas (Integra Radionics, Burlington, MA). For cervical lesioning, a 5-cm SMK cannula is needed, whereas for thoracic or lumbar lesioning, a 10-cm (sometimes a 15-cm) SMK cannula is necessary.

Basic mechanisms of radiofreqency lesioning

Figure 8-16 illustrates the difference in lesioning between PRFL and RFTC. RFTC cannot produce a lesion distal to cannula tip, as PRFL does. Instead, RFTC produces lesions only circumferentially around the shaft of the uninsulated active tip; the RFTC cannula must lie parallel to and within 2 mm of the target nerve.

Figure 8–16 The electric field in relation to the type of radiofrequency lesioning. A, In pulsed radiofrequency lesioning, strong electric fields emanate from the active tip of the cannula. B, Radiofrequency thermocoagulation occurs along the shaft of the cannula.

Procedure

Technical problems of the radiofrequency procedure may affect its efficacy. For accurate placement of the cannula, it is usually preferable to perform motor stimulation of the medial branch with 2 Hz and less than 0.5 V, followed by radiofrequency lesioning with the rotating curved needle technique (Figs. 8-19, 8-21, and 8-25).

Care must be taken, during injection of local anesthetics as well as during removal and re-insertion of the probe before radiofrequency lesioning, to avoid displacement of cannula, which can easily occur. Tandem placement of another block needle for injection of local anesthetics near the radiofrequency cannula has been suggested as an alternative method to avoid cannula displacement during the manipulation of the probe (Fig. 8-17).

Figure 8–17 Tandem placement of block needles along with the radiofrequency cannula at L3-L4 medial branch on lateral view (A) and at left L5-S1 medial branch on AP view (B).

If paravertebral rhythmic contractions cannot be elicited despite repeated attempts at motor stimulation, lesioning of a broader area can be performed on the basis of the radiographic anatomy. For PRFL based on the radiographic anatomy, the cannula tip is usually located 2 to3 mm behind the cannula tip position for RFTC, because the PRFL lesion is made from the tip of the cannula (Fig. 8-16).

If radiofrequency lesioning does not achieve significant pain relief even if the corresponding diagnostic MBB resulted in effective pain relief, radiofrequency lesioning should be repeated 1 month after the initial procedure.

If motor stimulation yields any of the following abnormal findings, RFTC should not be performed:

Cervical area: contractions occur in the face and upper extremities

Thoracic area: contractions occur in the segmental intercostal muscle

Lumbar area: contractions occur in the buttock and lower extremities

Procedures at the Cervical Level

The most commonly involved facet joints in patients with whiplash injury are the C2-C3 and C5-C6 facet joints [2].

Third Occipital Nerve and Medial Branch Blocks

Target medial branches for third occipital nerve and medial branch blocks are as follows:

For upper neck pain (usually C2-C3 through C4-C5 joint problems): third occipital nerve, C3 to C5 medial branches

For lower neck or upper back pain (usually C4-C5 through C6-C7 joint problems): C4 through C7 medial branches

The procedure for third occipital nerve block or MBB is as follows:

1. The patient’s written informed consent is obtained.

2. The patient is placed in the lateral position with the cervical and upper thoracic spinous processes aligned. The area of skin at the target points is prepared and draped in a sterile fashion.

3. With the fluoroscope, the bilateral articular pillars are superimposed in a lateral projection.

4. Infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle just over the target points (Fig. 8-18).

5. With the use of intermittent fluoroscopic guidance, a 23-gauge, 1.5-inch (sometimes 3.5-inch) needle is introduced directly to the target point, the centroid of the projection of the articular pillar, by means of the tunnel vision technique, until contact is made with the bone.

6. AP and lateral C-arm images are checked and recorded to verify the final position of the needle tip.

7. After correct placement of the needle is confirmed by administration of 0.2 mL of a contrast agent, 0.5 mL of local anesthetic (2% lidocaine or 0.5% levobupivacaine) is injected with or without corticosteroids.

Figure 8–18 The target points for a third occipital block (white circle) and medial branch blocks (red circles) in a lateral projection obtained with the C-arm. The bilateral articular pillars are superimposed.

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch

At the third occipital nerve

The procedure for PRFL or RFTC at the third occipital nerve is as follows:

1. The patient’s written informed consent is obtained.

2. The patient is placed in the lateral position with the cervical and upper thoracic spinous processes aligned. The area of skin at the target points is prepared and draped in a sterile fashion. An adhesive grounding pad is placed on the patient’s posterior upper arm if the probe is not self-grounded.

3. With the fluoroscope, the bilateral articular pillars are superimposed in a lateral projection (Fig. 8-18).

4. Infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle at the skin entry site (Fig. 8-18).

5. With use of intermittent fluoroscopic guidance, a 5-cm (sometimes 10-cm) cannula with a 5-mm active tip is introduced toward the midline of the C2-C3 facetal line until contact is made with bone. Thereafter the cannula is carefully advanced to the anterior surface of the facetal column while remaining in contact with the bone. The cannula should not be advanced beyond the anterior margin of the facetal column.

6. AP and lateral C-arm images are checked and recorded to verify the final position of the cannula tip.

7. The first lesion is made at this site by means of the rotating curved needle technique (Figs. 8-19 and 8-20). The second lesion is made with the same needle technique after the cannula is withdrawn about 5 mm from the first lesion site (Fig. 8-20).

Figure 8–20 Multiple-needle technique using straight cannulas. The multiple-needle technique is an alternative to the rotating curved needle technique.

Motor and sensory stimulations are not mandatory.

At the C3-C4 through C7-T1 facet joints

The procedure for PRFL or RFTC at the C3-C4 through C7-T1 facet joints is as follows:

1. The patient’s written informed consent is obtained.

3. With the fluoroscope, the bilateral articular pillars are superimposed in a lateral projection (Figs. 8-21 to 8-23).

4. With C-arm guidance, infiltration of local anesthetics is performed with a 22-gauge, 1.5-inch needle at the skin entry site (Fig. 8-21).

5. With use of intermittent fluoroscopic guidance, a 5-cm (sometimes 10-cm) cannula with a 5-mm active tip is introduced to the centroid of the facetal column (red circle on Fig. 8-21) until contact is made with the bone. The cannula is carefully advanced up to the anterior surface of the facetal column while 2 Hz and less than 0.5 V of stimulation is administered and contact with the bone is maintained. The cannula should be stopped when contractions occur, even before the anterior margin of the facetal column is reached.

6. AP and lateral images are checked to confirm the final position of the cannula tip.

7. Radiofrequency lesioning is performed with a rotating curved needle technique. The cannula should not be advanced beyond the anterior margin of facetal column.

Figure 8–22 Placement of the radiofrequency cannula at different cervical levels. The cannula is placed parallel to the upper and lower facetal lines. At C3 through C6, the cannula (white lines) is placed midway between the upper and lower facetal lines. At C7, the cannula (yellow line) should be located between upper and middle thirds of the C7 transverse process.

Figure 8–23 A, The area of skin at the target points is prepared and draped in a sterile fashion. B, Radiofrequency lesioning of the C3 and C4 medial branches is identified at lateral view.

If paravertebral rhythmic contractions cannot be elicited despite repeated attempts at motor stimulation, lesioning of a broader area can be performed on the basis of the radiographic anatomy. The needle trajectories for different cervical levels are shown in Figures 8-22 and 8-23. Sensory stimulation is not mandatory.

Procedures at the Thoracic Region

In the thoracic region, MBB is recommended because facet joint injection is very difficult to approach.

Targets for MBB in the thoracic region are as follows:

For T1 through T10 medial branches: superolateral corner of the transverse process

For T11 and T12 medial branches: the junctions between the superior articular processes and transverse processes

Medial Branch Block

The procedure for MBB in the thoracic region is as follows:

1. The patient’s written informed consent is obtained.

2. The patient is placed in the prone position. The area of skin at the target points is prepared and draped in a sterile fashion.

3. With the fluoroscope, the vertebral end plates are aligned parallel in an AP projection.

4. Under C-arm guidance, infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle just over the target point (Fig. 8-24).

5. With intermittent fluoroscopic guidance, a 23-gauge, 1.5-inch (sometimes 3.5-inch) block needle is introduced directly toward the target point, 2 to 3 mm medial to the superolateral corner of the transverse process, by means of a tunnel vision technique, until contact is made with the bone.

6. AP and lateral C-arm images are checked and recorded to verify the final position of the needle tip.

7. After correct placement of the needle is confirmed by administration of 0.2 mL of a contrast agent, 0.5 mL of local anesthetic (e.g., 2% lidocaine or 0.5% levobupivacaine) is injected with or without steroids.

Figure 8–24 Target points (red circles) for local anesthetic infiltration and medial branch block. C7, seventh cervical vertebra; L1, first lumbar vertebra; LB, lateral branch; MB, medial branch; T1, first thoracic vertebra; TP, transverse process.

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

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch

The procedure for PRFL or RFTC in the thoracic region is as follows:

1. The patient’s written informed consent is obtained.

2. The patient is placed in the prone position. The area of skin at the target points is prepared and draped in a sterile fashion. An adhesive grounding pad is placed on the patient’s posterior upper thigh if the probe is not self-grounded.

3. With the C-arm, the vertebral end plates are aligned parallel in an AP projection.

4. Under C-arm guidance, infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle just over the skin entry site (Fig. 8-25)

5. With intermittent fluoroscopic guidance, a 5-cm (sometimes 10-cm) cannula with a 5-mm active tip is introduced toward the target point (Fig. 8-25) by means of a tunnel vision technique until contact is made with the bone. The cannula is carefully advanced toward the superolateral corner of the transverse process while 2 Hz and less than 0.5 V stimulation is administered. The cannula should not be advanced past the point at which contractions occur, even if this is before the target point.

6. AP and lateral C-arm images are obtained to confirm placement of the cannula tip.

7. Radiofrequency lesioning should be performed with a rotating curved needle technique (Fig. 8-25). The cannula should not be advanced beyond the corner of the transverse process.

2. The patient is placed in the prone position. The area of skin at the target points is prepared and draped in a sterile fashion.

3. With the C-arm, the vertebral end plates are aligned parallel in an AP projection. The C-arm is then turned 20 to 40 degrees obliquely.

4. Under C-arm guidance, infiltration of local anesthetics is performed with 26-gauge, 1.5-inch and 3.5-inch needles just over the target point, centroid of the eye of the Scottie dog, with a tunnel vision technique.

5. With the use of intermittent fluoroscopic guidance, a 22-gauge, 3.5-inch block needle is introduced directly to the target point until contact is made with the bone.

6. AP and lateral C-arm images are checked and recorded to verify the final position of the needle tip.

Figure 8–26 An example of lumbar medial branch blocks. A. The needle direction and C-arm projection differ depending on the degree of lumbar lordosis. B. Different direction of needles are shown at oblique view.

At the L5-S1 facet joint

The procedure for MBB at the L5-S1 facet joint is as follows:

1. The patient’s written informed consent is obtained.

2. The patient is placed in the prone position. The area of skin at the target points is prepared and draped in a sterile fashion.

3. With the C-arm, the vertebral end plates are aligned parallel in an AP projection.

4. With C-arm guidance in a true AP view, infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle over the target point, about 5 mm inferior to the junction of the superior articular process and the ala of the sacrum.

5. With the use of intermittent fluoroscopic guidance, a 22-gauge, 3.5-inch block needle is introduced directly to the target point with a tunnel vision technique until contact is made with the bone.

6. AP and lateral C-arm images are checked and recorded to verify the final position of the needle tip.

Pulsed Radiofrequency Lesioning or Radiofrequency Thermocoagulation of the Medial Branch (L1-L4) or Dorsal Ramus (L5)

At the L1-L2 through L4-L5 facet joints

The procedure for PRFL or RFTC at the L1-L2 through L4-L5 facet joints is as follows:

1. The patient’s written informed consent is obtained.

3. With the C-arm, the vertebral end plates are aligned parallel in an AP projection. The C-arm is then turned 20 to 40 degrees obliquely.

4. Under C-arm guidance, infiltration of local anesthetics is performed with a 26-gauge, 1.5-inch needle at the skin entry site (red dot on Fig. 8-27A).

5. With the use of intermittent fluoroscopic guidance, a 10-cm (sometimes 15-cm) cannula with a 10-mm active tip is introduced toward the target point (blue dot on Fig. 8-27A) until contact is made with the bone. The cannula is carefully advanced toward Burton point (black dot on the Fig. 8-27A) while 2 Hz and less than 0.5 V stimulation is administered (Fig. 8-28) and contact with the bone is maintained. Advance of the cannula should be stopped when contractions occur, even if this is before Burton point is reached.

6. AP and lateral C-arm images are obtained to confirm placement of the cannula tip.

7. Radiofrequency lesioning should be performed with a rotating curved needle technique. The cannula should not be advanced beyond the facetal line on a lateral view (Fig. 8-27B).

Figure 8–28 Illustrations showing the typical twitching responses provoked by 2-Hz stimulation to locate the medial branch. If thumping, rhythmic contractions cannot be elicited at those sites with three or four stimulation trials, the final placement of the cannula is based on the physician’s judgment of a satisfactory location based on radiographic views.

(Adapted from Shin KM, Choi SE, Yun SH, et al: A new more reliable indicator for confirmation of the medial branch in radiofrequency neurotomy. Korean J Pain 2000;13:242-246.)

If paravertebral rhythmic contractions cannot be elicited despite repeated attempts at motor stimulation, lesioning of a broader area can be performed on the basis of the radiographic anatomy.