Lumbar Sympathetic Plexus Block

Lumbar sympathetic block
Anatomy
Lumbar sympathetic chain consist of 3-5 ganglia which lies anteriorly to the L2,L3 and L4 vertebral bodies.
It is anterior to the psoas muscle margin and fascia and posterior to vena cava on the right and aorta on the left side.
Indications
The following are the indications for lumbar sympathetic block:
• Inoperable peripheral vascular disease and vasospastic disease of the lower limbs
• Neuropathic pain
• Reflex sympathetic dystrophy/ Complex Regional pain syndrome (CRPS)
• Urogenic/ pelvic pain
• Cancer pain
• Phantom pain
• Herpes zoster involving lower limbs
CT guided lumbar sympathectomy with anhydrous ethanol is safe and effective in advanced PVD to stave off impending amputation. CT guidance increases accuracy of needle placement, decreases the volume of ablative chemical needed and may be able to reduce the incidence of complications.
Source: R Florek, C Sheehan, F. Alessi. Percutaneous lumbar sympathectomy: technique and clinical outcome review. Journal of Vascular and Interventional Radiology. April 2013. Vol 24. Issue 4
Fluoroscopy is used to guide the needle into the proper position and then injection is formed.
Technique
• Patient is placed in the prone position on a CT scanner table with a pillow underneath the abdomen to allow theflexion of thoraco-lumbar spine
• A scout film is taken and the L2 vertebral body is identified
• The skin overlying the transverse process of L2 is marked with gentian violet marker and then prepared with anti septic solution
• Utilizing a 1 ½ inch, 22 G needle, the skin and subcutaneous tissue are anesthetized with 1% lidocaine.
• A 22 gauge, 13 cm cm styleted needle is then advanced through the previously anesthetized area until tip rests against the vertebral body.
• The needle is then redirected in a trajectory to pass just lateral to the vertebral body
• A well lubricated glass syringe filled with preservative free saline is then attached, and loss of resistance technique is utilized while the needle is advanced through the body of psoas muscle
• As soon as the needle tip passes through the fascia of the muscle, loss of resistance is encountered
• A small amount of local anesthetic and water soluble contrast media is then injected to ensure the appropriate spread of contrast material in the preveretbral region
• Then 12 cc of 0.5% preservative free lidocaine or absolute alcohol is injected via the needle
• The needle is flushed with preservative free saline and removed
• The patient is then observed for hypotension and tachycardia secondary to sympathetic blockade.
Source: Pain Management: A practical guide for clinicians, 6th Edition. By Richard S. Weiner. Page 452-453.
Contraindications
• Patients on anticoagulant therapy
• Hemorrhagic disorders
• Local infection
• Local neoplasm
• Local vascular anomalies
Assessment of the block
1. Test dose
• Injection of 10 cc local anesthetic (1% lidocaine, 0.25% bupivacaine) should produce sympathetic blockade
• Within 5-10 min, there should be vasodilation, increased skin temperature
2. Psychogalvanic reflex
• 2 electrodes (ECG) for each channel attached to each foot (dorsal and plantar)
• Ground lead attached to any body surface
• It measures the changes in electrical resistance of the skin
• After stimulation, the side with blockade of sympathetic fibers will demonstrate no ECG deviation
 
3. Sweat test
• Ninhydrin test relies on sweat protein to change color to yellow
• Cobalt blue test filter paper color is changed to pink
• Starch iodide test relies on color change
4. Pain assessment
• Post block pain relief provides the indication of sympathetic blockade
• Pain relief can be immediate or delayed by several hours
 
Complications
• Spread of injectate into the subarachnoid space, epidural space
• Intravascular injection (vena cava, aorta and lumbar vessels)
• Damage by needle or neurolytic solution to kidneys, renal pelvis, ureters, intervertebral discs
• Infection
• Mild backache
• Neuropathic pain
• Retroperitoneal hematoma
• Sympathalgia
• Destruction of sympathetic fibers- produce cramping or burning pain in anterior thigh
• Sympathectomy mediated hypotension
• Intravascular steal- may occur in arteriosclerotic patients
• Failure of ejaculation
Source
Barash, Cullen, & Stoelting.  (2001).  Clinical Anesthesia (4th Ed.). Lippincott Williams & Wilkins. 
Hoerster W, Kreusher H, Niesel Chr.H, Zenz M, eds. Regional Anesthesia. 2nd ed. St. Louis, MS:Wolfe Publishing Limited; 1990:233-238.
Mekhail, N., Malak, O. Lumbar sympathetic blockade.  Techniques in Regional Anesthesia and Pain Management, 5(3); 2001: 99 - 101.
Miller, Ronald. Ed. Anesthesia, Fifth edition. Volume 2.  Philadelphia, Pa: Churchhill Livingstone; 2000.
Mulroy, MF. Regional Anesthesia An Illustrated Procedural Guide. 2nd ed. Boston, MA: Little, Brown and Company;1996:147-158.
Wildsmith JAW, Armitage EN, McClure JH, eds. Principles and Practice of Regional Anaesthesia. 3rd ed. Edinburgh, UK:Churchill Livingstone; 2003:293-311.