Anatomy

The stellate ganglion, which is formed by the fusion of the inferior cervical and T1 sympathetic ganglia, lies anterior to the transverse processes of C7 and T1 and to the neck of the first rib (Fig. 10-1).

Figure 10–1 Position of the stellate ganglion. C6, sixth cervical vertebra; T1, first thoracic vertebra.

(Modified from Justins DM: Pain and autonomic nerve block. In Wildsmith JAW, Armitage EN, McClure JH [eds]: Principles and Practice of Regional Anaesthesia, 3rd ed. Edinburgh, Churchill Livingstone, 2002, pp 291-309.)

Physical examinations that imply successful sympathetic nerve block consist of the following findings:

In face: Horner syndrome

In upper extremity: temperature elevation at the ipsilateral upper extremity.

Temperature measurements in both hands (Fig. 10-2) are required to evaluate successful upper extremity block [1]. Digital infrared thermal imaging is helpful (refer to Fig. 15-29) [2]. Horner syndrome does not guarantee success of ipsilateral upper extremity sympathetic block.

Figure 10–2 Monitoring of surface temperature during thoracic sympathetic block. For lumbar sympathetic block, the surface temperature monitoring probes are attached at the plantar surfaces of both feet.

Indications

The indications for stellate ganglion block include the following:

Headache

Acute or chronic face, cervical, or upper extremity pain

Raynaud’s disease

Complex regional pain syndrome

Ménière’s disease

Technique

Stellate ganglion block

The simplest and most satisfactory approach is the anterior paratracheal approach, which is performed as follows:

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

2. The patient is placed in supine position on a radiology table, with the head extended by placement of a roll under the neck.

3. The operator applies pressure with two fingers in the groove between the trachea and the carotid sheath to feel the transverse process of C6, which lies at the level of the cricoid cartilage (Fig. 10-3).

4. After sterile skin preparation, a 23-gauge, 3-cm needle is inserted directly backwards to strike the transverse process of C6. The needle should then be withdrawn 2 to 3 mm.

5. The operator fixes the needle in this position with one hand and performs an aspiration test for checking blood regurgitation.

6. 6 to 8 mL of local anesthetic (0.2%-0.375% ropivacaine or 0.125%-0.25% bupivacaine) is injected slowly with repeated aspiration tests. For complete sympathetic block of the upper limb to be obtained, the solution must extend to the T2 or T3 ganglion, and volumes greater than 10 mL may be necessary.

Figure 10–3 Landmarks for stellate ganglion block. The blue box indicates the cricoid cartilage and the blue dotted line represents the medial margin of the sternocleidomastoid muscle. The blue solid line represents the sternal notch. The transverse process of C6 is firmly held between the index and middle finger of the operator’s left hand. The needle should be inserted between the surgeon’s finger tips.

We prefer thoracic sympathetic block to stellate ganglion block for block of the upper extremity sympathetic nerve.

Anatomy

The upper thoracic sympathetic ganglia are located around the heads of the ribs and are covered by the pleura. The lower two or three ganglia are on the sides of the vertebral bodies. The thoracic sympathetic trunk runs between the ganglia and just in front of the somatic nerves (Fig. 10-4) [1].

Figure 10–4 The anatomical dissection of the thoracic sympathetic ganglia. Arrowheads indicate the rami communicantes. BP, brachial plexus; N1, the first intercostal nerve; N2, the second intercostal nerve; N3, the third intercostal nerve; N4, the fourth intercostal nerve; SG, stellate ganglion; T2, the second thoracic sympathetic ganglion; T3, the third thoracic sympathetic ganglion; T4, the fourth thoracic sympathetic ganglion.

(Adapted from Cho HM, Lee DY, Sung SW: Anatomical variations of rami communicantes in the upper thoracic sympathetic trunk. Eur J Cardiothorac Surg. 2005;27:320-324.)

Indications

The indications for nerve block, radiofrequency lesioning, or neurolysis of the thoracic sympathetic ganglion include the following:

Upper extremity vascular disease

Complex regional pain syndrome in the upper extremity

Hyperhidrosis

Techniques

Thoracic sympathetic block

The following procedure is used for thoracic sympathetic block:

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

2. The patient is placed in the prone position on a radiology table.

3. The temperature probes for surface temperature monitoring are attached to the palms of both hands to monitor the temperature changes (Fig. 10-2).

4. The overlying skin is prepared and draped in a sterile fashion.

5. The C-arm is rotated in the caudocephalad direction to align the end plates of the T2 and T3 vertebrae parallel in the AP projection.

6. Then the C-arm is rotated to a 10- to 15-degree oblique angle, toward the side being injected (Fig. 10-5A).

7. The skin entry points are identified and infiltrated midway between the transverse processes of T3 and T4, which meet at the lateral margin of the vertebral column in the oblique projection.

8. A 21-gauge, 15-cm Chiba needle is advanced by means of the tunnel vision technique and with C-arm guidance to the lateral margin of vertebral column in the oblique projection.

Figure 10–5 Typical pattern of contrast agent spread thoracic sympathetic block in oblique (A) and anteroposterior (B) fluoroscopic images. No intravascular, intrathecal, epidural, or intrapleural spread of contrast agent is noted in either image.

To reduce the risk of pleural puncture, advancing the needle beyond the lateral margin of the vertebral column in the oblique view should be avoided. Frequent checks of lateral images should be made to measure the depth of the needle tip, especially when the needle enters the thoracic cavity.

9. If the needle touches the lateral margin of the vertebral column in oblique projection, the C-arm is rotated to lateral projection. Then the needle is carefully manipulated to arrive at the target point, the posterior third of the vertebral body. The needle tip should be kept close to the vertebral body during this step.

10. 0.5 to1 mL of contrast agent is injected to confirm compartmental flow of the injectate and to rule out any intravascular, intrathecal, epidural, or intrapleural spread (Fig. 10-5). Epidural spread can easily be detected in the oblique projection (Fig. 10-5A).

11. 2 to 3 mL of local anesthetic (0.2%-0.375% ropivacaine or 0.125%-0.25% bupivacaine) can be injected.

12. For neurolysis of thoracic sympathetic ganglions, diagnostic thoracic sympathetic block is performed at both the T2 and T3 levels, with injection of 1 to 1.5 mL of the local anesthetic at each level. A neurolytic agent, such as 99% alcohol, should be injected 20 to 30 minutes after the diagnostic block.

In cases in which intrathecal, epidural, intercostal nerve, or intrapleural spread of contrast agents has occurred, neurolytics should not be injected, and the procedure should be postponed for about 1 week. If at any time during the neurolytic injection the patient complains of pain, further injection should be stopped immediately.

13. After neurolytic injection, absolute bed rest for 3 to 4 hours without position change is necessary to avoid unwanted spread of neurolytics to important adjacent structures.

Complications

The complications of thoracic sympathetic ganglion block, radiofrequency lesioning, or neurolysis include the following:

Pneumothorax

Subarachnoid or epidural injection

Somatic nerve injury (neuritis)

Anatomy

As shown in Figure 10-6, the greater (T5 through T10), lesser (T10 and T11), and least (T11 and T12) splanchnic nerves cross the lateral side of the body of T12 as they sweep forward to penetrate the diaphragm and form the celiac plexus. The pleura are attached posteriorly to the vertebral bodies and create a well-defined compartment.

Figure 10–6 Position of the splanchnic nerves and celiac plexus. T10, tenth thoracic vertebra; L1 and L2, first and second lumbar vertebrae.

(Modified from Justins DM: Pain and autonomic nerve block. In Wildsmith JAW, Armitage EN, McClure JH [eds]: Principles and Practice of Regional Anaesthesia, 3rd ed. Edinburgh, Churchill Livingstone, 2002, pp 291-309.)

Indications

Indications for splanchnic nerve block, radiofrequency lesioning, or neurolysis include the following:

Pain secondary to acute or chronic pancreatitis

Visceral arterial insufficiency

Cancer pain secondary to malignancies of the retroperitoneum and upper abdomen

Contraindications

Contraindications to splanchnic nerve block, radiofrequency lesioning, or neurolysis include the following:

Local infection

Coagulopathy

Anatomic change due to tumor

Abdominal aortic aneurysm

Anatomic change due to tumor; the case that the celiac compartment is entirely occupied with metastatic cancer cannot be performed

Techniques

Splanchnic nerve block

The procedure for splanchnic nerve block is as follows:

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

2. Rapid hydration is administered with 500 to 1000 mL of normal saline or Hartmann’s solution before the block, especially if the block will be performed bilaterally.

3. The patient is placed in the prone position on a radiology table.

4. The overlying skin is prepared and draped in a sterile fashion.

5. The C-arm is rotated in the caudocephalad direction to align the end plates of T11 and T12 parallel in an AP projection.

6. Then the C-arm is rotated to a 20- to 30-degree oblique angle toward the side being injected.

7. The skin entry point is identified and infiltrated at the point at which the rib meets T11 or T12 in the oblique projection.

8. A 21-gauge, 15-cm, curved-tipped Chiba needle is advanced by means of a tunnel vision technique under C-arm guidance to the lateral margin of the vertebral column in oblique projection.

To reduce the risk of pneumothorax, advancing the needle beyond lateral margin of the vertebral column in the oblique view should be avoided. The lateral images should be checked frequently to measure the depth of the needle tip.

9. If the needle touches the lateral margin of vertebral column in the oblique projection, the C-arm is rotated to the lateral direction. With the lateral projection, the needle is advanced until it reaches the target point, the junction between the anterior third and middle third of the T11 or T12 vertebral body (Fig. 10-7).

10. 1 to 2 mL of contrast agent is injected to confirm compartmental flow of the injectate and to rule out any intravascular or intrapleural spread.

11. 5 to 10 mL (<15 mL) of local anesthetic (0.2%-0.375% ropivacaine or 0.125%-0.25% bupivacaine) can be injected.

Figure 10–7 The needle tip is located at the junction of the anterior and middle thirds of the T12 vertebral body in lateral (A) and anteroposterior (B) fluoroscopic images. Injection of contrast agent should show that the spread of the agent is limited anteriorly and inferiorly by the crus of the diaphragm and posteriorly by the attachment of the pleura to the vertebra.

Pulsed radiofrequency lesioning or radiofrequency thermocoagulation

Figure 10-8 illustrates splanchnic nerve neuroablation. The following principles apply:

As in the splanchnic nerve block at T11 or T12, PRFL or RFTC must be accomplished with fluoroscopic guidance and the use of a 22-gauge, 15-cm, curved-tipped cannula with a 15-mm active tip (Figs. 8-14 to 8-16).

Sensory (50 Hz, 1 V) and motor (2 Hz, > 2 V) stimulation must be performed.

Figure 10–8 Lateral (A) and anteroposterior (B) fluoroscopic images of splanchnic nerve neuroablation with radiofrequency.

During the sensory stimulation, the patient may report stimulation in the epigastric region, which is a typical and satisfactory sign of stimulation. If sensory stimulation occurs in a girdle-like fashion around the intercostal space, the cannula must be advanced further anteriorly.

Radiofrequency Thermocoagulation

The following principles apply to RFTC of the splanchnic nerve:

Impedance should be checked before lesioning. A reading of less than 500 ohms confirms placement of the probe; if the impedance is greater than 500 ohms, the probe should be removed, 0.5 mL of local anesthetics should be injected, and then the probe should be reinserted.

After injection of 2 to 5 mL of local anesthetic, a lesion is made by raising the temperature of the cannula tip to 80° C for 90 seconds. The second lesion at the same setting is made by turning the cannula 180 degrees (refer to the “rotating curved needle technique” in Figs. 8-198-21, and 8-25).

After the RFTC, 5 mg of triamcinolone is injected through the cannula for relief of postprocedural pain attributable to the trauma of the cannula insertion and the thermal lesion around the target sympathetic ganglion.

Pulsed Radiofrequency Lesioning

PRFL is performed with the following parameters: 42° C, 120 seconds, 2 to 4 times. The same technique is applied as in RFTC, except that the lesioning temperature is lower but the time is increased.

Complications

Complications of nerve block, radiofrequency lesioning, or neurolysis of the splanchnic nerve include the following:

Hypotension

Diarrhea

Pneumothorax

Intrathecal or epidural injection

Anatomy

The celiac plexus is formed by the union of the greater (T5 through T10), lesser (T10 and T11), and least (T11 and T12) splanchnic nerves with the celiac branch of the right vagus (Fig. 10-6). It therefore contains both sympathetic and parasympathetic fibers. There are usually two ganglia at the level of the lower part of the T12 and the upper part of the L1. The ganglia lie in the retroperitoneal space, between the suprarenal glands, posterior to the stomach, pancreas, and the left renal vein, anterior to the crura of the diaphragm, and mainly anterolateral to the aorta. The kidneys are in close relationship.

Indications and Contraindications

The indications for and contraindications to celiac plexus block are the same as those listed for splanchnic nerve block.

Technique

Oblique approach

Celiac plexus block using the oblique approach is performed as follows:

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

2. Rapid hydration is administered with 500 to 1000 mL of normal saline or Hartmann’s solution before the block, especially if the block will be performed bilaterally.

3. The patient is placed in the prone position on a radiology table.

4. The overlying skin is prepared and draped in a sterile fashion.

5. The C-arm is rotated in the caudocephalad direction to align the end plates of L1 and L2 parallel in an AP projection.

6. Then the C-arm is rotated to a 25- to 30-degree oblique angle toward the side being injected.

7. The skin entry point is identified and infiltrated with local anesthetics at the lateral edge of L1 in the oblique projection.

8. A 21-gauge, 15-cm curved-tipped Chiba needle is advanced by means of a “tunnel vision technique” under C-arm guidance to the lateral margin of vertebral column in oblique projection.

9. If the needle touches the lateral margin of L1 in oblique projection, the C-arm is rotated to the lateral direction. Guided by a lateral projection with the fluoroscope, the needle is advanced until it lies at the anterior edge of L1. The needle tip should be kept close to the vertebral body during this step. A second needle is inserted on the opposite side if needed.

10. A 10-mL syringe containing normal saline is connected to the block needle, and the needle is advanced 1 to 2 cm with intermittent injection of normal saline until a sudden increase of resistance is felt.

11. 5 mL of contrast agent is injected to confirm compartmental flow of the injectate and to rule out any intravascular spread (Fig. 10-9).

12. 10 mL of local anesthetic (0.2%-0.375% ropivacaine or 0.125%-0.25% bupivacaine) can be injected.

13. For neurolysis of celiac ganglions, 10 to 15 mL of a neurolytic agent, such as 99% alcohol, should be injected on each side 20 to 30 minutes after the diagnostic block.

Figure 10–9 Correct needle position and contrast agent spread for celiac plexus block in lateral (A) and anteroposterior (B) fluoroscopic images. Injected contrast agent spreads in the longitudinal axis without any lateral or posterior extension.

If at any time the patient complains of pain during the neurolytic injection, further injection of neurolytics is immediately stopped.

14. After neurolytic injection, absolute bed rest for 3 to 4 hours without position change is necessary to avoid unwanted spread of neurolytics to adjacent important structures.

A single-needle, transaortic approach

This technique is recommended only if difficulties are encountered when the standard approach is used for a neurolytic plexus block in a patient with cancer. The single-needle, transaortic approach differs from standard approach as follows:

The needle is inserted on the left side and positioned to ensure that its point is in the middle of the celiac plexus.

The needle is inserted as in the standard approach and advanced until a characteristic “click” and aspiration of blood confirm that the tip is in the aorta.

The needle is then advanced through the anterior aortic wall. The point must lie in an area of very low resistance to injection and not in the wall of the aorta.

Complications

Complications of celiac plexus nerve block include the following [1]:

Local pain (96%)

Hypotension (38%)

Diarrhea (44%)

Paraplegia due to anterior spinal cord syndrome

Other neurologic complications, such as weakness and paresthesia (1%), after spread of neurolytic solution to the lumbar somatic nerves and inadvertent epidural or intrathecal injection

Anatomy

As shown in Figures 10-10 and 10-11, the lumbar sympathetic trunk is situated in the retroperitoneal connective tissue anterior to the vertebral bodies and the medial margin of psoas muscle. The aorta and the inferior vena cava are anterior relations, the genitofemoral nerve lies laterally on psoas, and the kidney and ureter are posterolateral in position.

Figure 10–10 Transverse section through L3 to show the position and relationships of the lumbar sympathetic chain. n., nerve.

Figure 10–11 A, Drawing of the location of the typical sympathetic trunk and rami communicantes. Four sympathetic ganglia are shown on the L2 vertebra, the L2-L3 disc, the L3-L4 disc, and the L5 vertebra. The sympathetic trunk lies anteriorly at the vertebral column from L1 to L4 and passes to the lateral side of L5. A cadaver study was conducted by Murata et al in which each lumbar vertebra was divided into three zones (U, upper third; M, middle third, L, lower third), and each disc was regarded as an additional zone (D) in the sagittal plane, for a total of 20 zones. B, The average number of ganglia found by Murata et al in each zone per sympathetic trunk. The sky blue bars show the average number of ganglia in each zone per sympathetic trunk, and the lines represent the standard deviation of the mean. The zones found to have a higher than average number of ganglia are zones L2M through L3D, L5U, and L5M. The average number of ganglia in these nine zones was 0.33. Moreover, 63 sympathetic chains from a total of 40 specimens had no ganglia at all on the L1 (zones L1U to L1L) and L4 (zones L4U to L4L). These data indicate that the sympathetic ganglia were distributed mainly on the L2 and L3.

(Modified from Murata Y, Takahashi K, Yamagata M, et al: Variations in the number and position of human lumbar sympathetic ganglia and rami communicantes. Clin Anat 2003;16:108-113.)

All the sympathetic fibers pass through or synapse at the L2 ganglion, so in theory, a block at the upper level of L3 should abolish all the sympathetic supply to the lower limb; opinions differ, however, over the number of levels that must be injected to produce optimal lower limb sympathectomy. Murata and colleagues [3] reported four lumbar sympathetic ganglia (on the L2 vertebra, the L2-L3 disc, the L3-L4 disc, and the L5 vertebra) and demonstrated that the sympathetic trunk runs on the anterior surface of the vertebral column from L1 to L4 levels and then passes to the lateral side.

A single-level injection is safer and faster to perform, and the spread of solution can be observed with the image intensifier. If it is insufficient, the injection can be repeated at an adjacent level.

Usually, four pairs of lumbar arteries arise from the aorta and wind around the upper four lumbar vertebral bodies, deep to the sympathetic trunks and under the tendinous arches that give origin to the psoas muscle. The arteries are often accompanied by lumbar veins, which may form plexiform networks. All of these vessels are vulnerable to penetration by needles during nerve blocks.

Indications

Indications for nerve block, radiofrequency lesioning, or neurolysis of the lumbar sympathetic nerve include the following:

Circulatory insufficiency (Berger’s disease, arteriosclerotic vascular disease, diabetic gangrene, Raynaud disease)

Complex regional pain syndrome in the lower extremity

Stump or phantom pain

Frostbite

Hyperhidrosis in the foot

Technique

Lumbar sympathetic block

The block is usually performed with the patient prone. However, the lateral position may be used in the patient who cannot lie prone.

Blocks for the lower limb (e.g., for peripheral vascular disease or complex regional pain syndrome) usually target L3 and L4.

Oblique Approach in the Prone Position

Lumbar sympathetic block using the oblique approach with the patient in the prone position is performed as follows:

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

2. Rapid hydration is administered with 500 to 1000 mL of normal saline or Hartmann’s solution before the block, especially if the block will be performed bilaterally.

3. The patient is placed in the prone position on a radiology table.

4. The temperature probes for surface temperature monitoring are attached to the soles of both feet, and the temperature changes are monitored.

5. The overlying skin is prepared and draped in a sterile fashion.

6. The spinous process of L3 is identified with the C-arm (fluoroscope) (Fig. 10-12).

7. The C-arm is rotated in the caudocephalad direction to align the transverse process with the upper part of L3 in an AP projection, to avoid obstructing of the passage of the needle. It is essential to ensure that the transverse process will not obstruct the passage of the needle; otherwise correct placement would be difficult or even impossible.

8. Then the C-arm is rotated to a 25- to 30-degree oblique angle toward the side being injected, and the skin entry point is identified at the lateral edge of L3 in the oblique projection (Fig. 10-13).

9. Infiltration of local anesthetic is performed at the skin entry site (Fig. 10-14).

10. A 21-gauge, 15-cm, curved-tipped Chiba needle is advanced by means of a “tunnel vision technique” under fluoroscopic guidance with the C-arm in the oblique projection to the lateral margin of the vertebral column (Fig. 10-15).

11. If the needle touches the lateral margin of L3 in the oblique projection, the C-arm is rotated to the lateral direction.

12. With the lateral projection, the needle is advanced until the needle lies to the anterior edge of L3. The needle tip should be kept close to the vertebral body during this step (Fig. 10-16). A characteristic “click” is often felt as the needle passes through the psoas fascia. The needle tip at this stage is shown to lie just outside the facetal line on an AP image. A second needle is inserted on the opposite side if needed.

13. Injection of contrast agent should demonstrate linear spread in the longitudinal axis without any lateral or posterior extension (Fig. 10-16). Injection into the psoas muscle produces a characteristic pattern of inferolateral spread away from the vertebral body (Fig. 10-17). If contrast agent spreads into the psoas muscle, the needle tip is located too posteriorly or too laterally and should be repositioned more medially or anteriorly.

Occasionally, the contrast agent disappears into small vessels, even when the aspiration test result is negative [4]. In such cases, adjustment of the needle tip is necessary. If contrast agent spreads only anterior to the vertebral body, the block will fail.

14. If the pattern of contrast agent spread from the initial level of injection is satisfactory, all of the solution should be injected at that level. If the spread is not entirely satisfactory, it may be possible to use a small volume of solution at that level and to repeat the procedure at vertebral levels above or below.

Figure 10–12 Landmark for lumbar sympathectomy at the level of L3. The spinous process of L3 is identified on surface of body (A) and at AP fluoroscopic view (B).

Figure 10–13 Landmark for needle insertion for lumbar sympathectomy at the level of L3. The skin entry point is identified at the lateral edge of L3 vertebral body on surface of body (A) and at the oblique fluoroscopic projection while C-arm is rotated to a 25- to 30-degree oblique angle toward the side being injected. (B)

Figure 10–14 Infiltration of local anesthetic at the skin entry site. Insertion of needle at skin entry point which was identified at previous step is shown on surface of body (A) and oblique fluoroscopic view. (B)

Figure 10–15 The needle inserted along the direction of the fluoroscopic view.

Figure 10–16 Typical spreading of contrast agent during lumbar sympathetic block, in lateral (A) and anteroposterior (B) images from the fluoroscope.

Figure 10–17 Lateral (A) and AP (B) fluoroscopic images showing that contrast agent has spread along the psoas muscle.

Oblique Approach in the Lateral Position

The major problem in using the oblique approach for lumbar sympathetic block in the lateral position is positioning the patient. Once the patient is accurately positioned, the procedure is essentially the same as described for the prone position.

Radiofrequency lesioning

Figure 10-18 illustrates RFTC of the lumbar sympathetic nerve; the principles for radiofrequency lesioning are as follows:

Radiofrequency lesioning must be performed under fluoroscopic guidance as for the lumbar sympathetic block at the inferior third of L2 and the upper third of L3, with use of a 22-gauge, curved-tipped, 15-cm long cannula with a10-mm active tip (Figs 8-14 to 8-16).

Sensory and motor stimulation must be performed. During the sensory stimulation (50 Hz, 0.5-1.0 V), the patient may report feeling vague discomfort in the back. If paresthesia exists in the groin, the cannula must be repositioned because of its proximity to the genitofemoral nerve. If fasciculation in the lower extremity is observed during the motor stimulation (2 Hz, 2 V), the cannula must be repositioned owing to its proximity to the spinal nerves.

Figure 10–18 Lateral (A) and anteroposterior (B) fluoroscopic images of radiofrequency thermocoagulation at L2 and L3 levels.

Radiofrequency Thermocoagulation

The following principles apply to RFTC of the lumbar sympathetic nerve:

Impedance should be checked before lesioning. Correct placement of the probe is confirmed by a reading of less than 500 ohms; if impedance is greater than 500 ohms, the probe must be removed, 0.5 mL of local anesthetics must be injected, and the probe must be reinserted.

After injection of local anesthetics, a lesion is made by raising the temperature of the cannula tip to 60-80° C for 90 seconds. The second lesion at the same setting is made by turning the cannula 180 degrees (refer to the “rotating curved needle technique” in Figs. 8-198-21, and 8-25).

After RFTC, 5 mg is injected through the cannula for relief of postprocedural pain attributable to the trauma of the cannula insertion and the thermal lesion around the target sympathetic ganglion.

Pulsed Radiofrequency Lesioning

PRFL is performed with the following parameters: 42°C, 120 seconds, 2 to 4 times. The same technique is used as for RFTC, with the following exceptions:

The lesioning temperature is lower but the time is longer.

The needle tip is usually located somewhat posterior (2-3 mm) to the anterior edge of the vertebral margin.

To reduce impedance, 1 mL of normal saline is injected through the cannula instead of local anesthetics.

Chemical neurolysis

For neurolysis of lumbar sympathetic ganglions, diagnostic block should be performed at both the L2 and L3 levels with use of 1 to 1.5 mL of local anesthetic at each level. Neurolysis of lumbar sympathetic ganglion at L1 level, especially bilateral, is not recommended because of the complications, such as failure of ejaculation.

Careful evaluation of the presence of anesthesia at the area innervated by the genitofemoral nerve (refer to Fig. 12-4) is essential before neurolytic injection.

1 to 1.5 mL of a neurolytic agent, such as 99% alcohol, should be injected on each level 20 to 30 minutes after the diagnostic block.

If at any time the patient complains of pain during the neurolytic injection, further neurolytic injection should be stopped immediately.

After the neurolytic injection, absolute bed rest for 3 to 4 hours without position change is necessary to avoid unwanted spread of neurolytic agents to important adjacent structures.

Complications

Complications of chemical neurolysis of the lumbar plexus include the following:

Inadvertent injection of alcohol into the vertebral canal, the peritoneal cavity, or blood vessel, which is avoidable when the procedure is performed under C-arm guidance.

Damage by the needle or neurolytics to the kidney, renal pelvis, ureter or intervertebral discs, which is also avoidable when the procedure is performed under C-arm guidance.

Injury to blood vessels in the posterior abdominal wall, which is not uncommon.

Mild backache, which is common.

Sympathalgia: cramplike or burning pain and dysesthesia in the anterior thigh due to destruction of sympathetic fibers.

Genitofemoral neuralgia, which may be caused by spread of alcohol to the genitofemoral nerve.

Hypotension.

Failure of ejaculation.

Complications

Complications of block or chemical neurolysis of the inferior mesenteric plexus include the following:

Mild backache

Hypotension

Diarrhea

Injury to major organs including blood vessels, kidney, or ureter

Acute alcohol toxicosis

Complications related to unintentional lumbar sympathetic blockade or neurolysis (refer complications lumbar sympathetic blockade or neurolysis)

Anatomy

The superior hypogastric plexus, which innervates the pelvic viscera, lies retroperitoneally in the lower third of L5 and in the upper third of S1.

Indications

Indications for nerve block of the superior hypogastric plexus include the following:

Gynecologic pain from endometriosis, adhesion, and chronic inflammation

Interstitial cystitis

Irritable bowel syndrome

Pain from malignancies of the pelvic viscera

Technique

The procedure for superior hypogastric plexus block is as follows:

11. For neurolysis of superior hypogastric ganglions, 8 mL of a neurolytic agent, such as 99% alcohol, should be injected on each side 20 to 30 minutes after the diagnostic block.

Figure 10–19 Anteroposterior (A) and lateral (B) fluoroscopic images show spread of contrast agent during superior hypogastric plexus block or neurolysis.

If at any time the patient complains of pain during the neurolytic injection, further neurolytic injection is stopped immediately.