Lumbar Sympathetic Block
Lumbar sympathetic blockade is indicated for diagnosis, prognosis, and therapy of circulatory and painful conditions such as:
Inoperable peripheral vascular disease and vasospastic disease of the lower extremities
Reflexive sympathetic dystrophies
Herpes Zoster involving the lower extremities
Patients on anticoagulant therapy
Allergies to medications injected
Local vascular anomalies
Volume of at 15 25ml must be injected
Short-acting local anesthetic, such as 1% lidocaine, is commonly used for diagnostic sympathetic block
Longer-acting agents, such as 0.25%- 0.375% bupivacaine, is advantageous for both diagnostic or therapeutic block
Higher percentages of bupivacaine are typically not used related to chance of motor block
Epinephrine (adrenaline) or Clonidine may be added to prolong the effects of the injection.
For Neurolytic Blockade:
Volume of 2 4ml at both L3 and L4, using 6 10% phenol or 50 100% alcohol
The lumbar sympathetic chain:
consists of three to five ganglia
lies anteriorly to the L2, L3, and L4 vertebral bodies
are anterior to the psoas muscle margin and fascia
are usually posterior to the vena cava on the right
is posterior to the aorta on the left
Positioning (either prone or lateral)
Prone Patient Positioning
The patient lies prone with a pillow under the lumbar spine
Patient and anatomic landmarks more stable
Bilateral blocks performed more easily
Spinous process of L2 and L3 are identified and marked
A horizontal line is drawn through the midpoint of the L2 interspace and extended 5cm to the right and left of midline
An X marks these spots (which should overlie the space between the transverse process of the 2nd and 3rd vertebrae or the cauded edge of the 2nd transverse process)
Skin and deeper tissues infiltrated with local anesthetic at the X.
A 10cm 20 g needle is inserted on each side through the X and angled 30-45 degrees cephalad.
Advance until the needle comes in contact with the transverse process. Mark the depth of the needle.
Withdrawl slightly, angle caudad, and walk inferiorly off the transverse process (usually in a direction perpendicular to the skin). A slight medial anqulation is used in hope of contacting the vertebral body.
Once contact is made with vertebral body, anterior repositioning of needle is made to walk off that body (the needle tip should remain close to vertebra).
Pop felt as needle passes through psoas fascia
Anteroposterior x-ray at this stage should show needle tip midway between lateral edge of vertebral body and spinous process
Injection of contrast solution should demonstrate linear spread in longitudinal axis without any lateral or posterior extension
Lateral Patient Positioning
Reserved for patient who cannot lie prone
Spinous processes of lumbar vertebrae, twelfth rib, iliac crest
Point of entry 6-7 cm paravertebrally from midline in the middle between iliac crest and twelfth rib
Place pillow under flank
After placing a skin wheal, 12 cm long needle is advanced toward the body of L2 in medioventral direction
If bone contact is made at depth of 2-3 cm, needle is redirected cephalad or caudally
If sharp radiating leg pain encountered needle is redirected cephalad or caudally
When needle contacts L2 body at depth of 6-8 cm, the needle is withdrawn 1-2 cm and readjusted upward to bypass L2 body
Aspiration in two planes
Local anesthetic injection should be achieved without resistance
Lumbar sympathetic blocks are commonly preformed under radiographic imaging, especially if a neurolytic drug is used.
Needle placement under x-ray control with contrast medium. (left)
Flouroscopic guidance with injection of radiocontrast solution increases the success rate and may reduce complications
Assessment of the Block
A test dose is inserted after careful aspiration.
Inject 10cc of local anesthetic solution this should produce sympathetic blockade.
1% lidocaine, 0.25% bupivacaine, or an equivalent concentration is adequate.
Within 5-10 minutes, one should note:
Increased skin temperature
There should be a minimum change of 2 degrees C if there is a proper block
Two electrodes (ECG) for each channel attached to each foot (dorsal and plantar)
Ground lead attached to any body surface
Measures changes in electrical resistance of the skin
After stimulation, the side with blockade of sympathetic fibers will demonstrate no ECG deviation
Ninhydrin test relies on sweat protein to change color to yellow
Cobalt blue test filter papers which are saturated with cobalt blue; sweat changes paper color to pink
Starch-iodine test relies on color change
Post-block pain relief provides indication of sympathetic blockade
Pain relief can be immediate or delayed for several hours
If narcotics or sedative drugs have been employed, pain assessment results may be immediately skewed
The most troublesome and frequent complication is simultaneous blockade of L2 somatic nerve root
Inadvertent injection into the subarachnoid space, epidural space, intravascular (vena cava, aorta, lumbar vessels
Damage by needle or neurolytic solution to the kidneys, renal pelvis, ureters, intervertebral discs
Destruction of sympathetic fibers - Produces cramping or burning pain in anterior thigh
Intravascular Steal - May occur in arteriosclerotic patients
Failure of ejaculation - Real risk after bilateral block. The risk must be explained to male patients.
COMPLICATIONS WITH THIS TECHNIQUE ARE UNUSUAL!!