Targeting Gray Rami Communicantes in Selective Chemical Lumbar Sympathectomy

Summary

We present a protocol for selective chemical lumbar sympathectomy (CLS), which inactivates only gray rami communicantes and not the sympathetic trunk. Selective CLS can help achieve therapeutic efficacy in vasodilation, sweat reduction, and pain relief that are comparable to conventional CLS, and serious complications, particularly ureteropelvic damages, can be reduced.

Abstract

Chemical lumbar sympathectomy (CLS) is a commonly used, minimally invasive procedure for the treatment of conditions including ischemic diseases of the lower extremities, hyperhidrosis, etc. It is commonly practiced to position the puncture needle tip in front of the anterior fascia of the psoas major muscle and inject the inactivating agent around the sympathetic trunk, which is defined as conventional CLS. Although relatively rare, ureteropelvic damage is the most frequently reported complication of conventional CLS and can cause serious harm to patients. We found that injecting the inactivating agent behind the anterior fascia, which only targets gray rami communicantes, helped achieve therapeutic efficacy in vasodilation, sweat reduction, and pain relief comparable to conventional CLS, and serious complications were largely reduced. We define this procedure as selective CLS. Here, we present a protocol of selective CLS. The precise needle tract and accurate evaluation of the spreading of the contrast agent are critical to ensure that the drug is injected behind the anterior fascia of the psoas major muscle. The needle tip is at approximately one-third the dividing line of the vertebral body in the lateral view of a lumbar X-ray. The contrast is mainly confined around the needle tip and spreads outward and downward along the psoas muscle fibers. In this way, the anterior fascia provides a natural barrier for the ureteropelvic area, and the psoas major muscle provides a natural barrier for the lumbar nerve root. There are several highlights of this article, including 1) a detailed description of the selective CLS procedures, 2) an explanation of the anatomical basis for the implementation of selective CLS, and 3) an explanation of the differences between selective and conventional CLS.

Introduction

Chemical lumbar sympathectomy (CLS) has been shown to be an effective treatment for ischemic diseases^1,2,3,4,5 including thromboangiitis obliterans (sometimes called Buerger's disease), ischemic diabetic foot, Raynaud's disease, parmoplantar hyperhidrosis⁶, erythromelalgia^7,8,9, and livedo reticularis¹⁰. It has replaced open surgery due to a number of advantages. It is minimally invasive and economically attractive, it does not require general anesthesia and hospitalization, and it can be performed repeatedly. However, exquisite precision is critical. For example, paraplegia has been reported in CLS using blind technique¹¹. The precision of the procedure is greatly improved with radiographical guidance to control the exact position of the puncture needle tip and puncture path and depth, through the use of contrast media to visualize treatment areas. However, even with radiographical guidance, damages to adjacent organs, particularly ureteropelvic organs^{12,13,14,15,16,17,18,19}, have still been reported.

It is commonly practiced to position the needle tip beyond the anterior fascia of the psoas major muscle and inject the drug around the sympathetic trunk^{8,12,13,14,15}, which we define as conventional CLS. However, because the location of the sympathetic trunk and ureter are both in front of the anterior fascia, inactivating agents may spread to the ureter and cause damage. In reports of ureteropelvic damage that presented radiographic images^12,13,14,15, the drug was injected in front of the anterior fascia, according to contrast spreading.

Based on our prior experience performing CLS procedures, we have found that targeting gray rami communicantes comparably effective and safer compared to targeting the sympathetic trunk. Gray rami communicantes are postganglionic sympathetic fibers located behind the sympathetic trunk and in front of the lumber nerve root, running along the lateral edge of the vertebral body, mostly within the psoas major muscle. Thus, the anterior fascia provides a good barrier for the ureteropelvic area, and the psoas major muscle provides a good barrier for the lumbar nerve root. We define this procedure as selective CLS, and the technical details of selective CLS are described in this protocol.

Protocol

The protocol has been approved by the local medical and ethics committees. The procedure lasts approximately 15 min per side.

1. Indications

1. Ensure the patient has the following indications for CLS: thromboangiitis obliterans (Buerger's disease), ischemic diabetic foot, Raynaud's disease, parmoplantar hyperhidrosis, erythromelalgia, phantom limb pain, or livedo reticularis of the lower extremities.

2. Contraindications

1. Exclude the patient if any of the following contraindications are fulfilled: spinal deformity, bleeding tendency, any infection in the procedure-involved areas, unstable vital signs, pregnancy, or any conditions that render the ability for compliance with the procedure.

3. Preoperative Preparation

1. Confirm the presence of indications and lack of contraindications based on clinical and laboratory results.
2. Obtain written, informed consent from the patient/relative.

4. Treatment Procedure

1. Patient position: ensure that the patient is in lateral decubitus position with the side to be treated facing upwards and the lower limbs flexed to make the back as stretched as possible.
2. Disinfection: disinfect the skin at the planned needle puncture site (approximately 30 cm diameter) with 2% entoiodine, twice. Then, cover the patient's back with surgical towels.
3. Anesthetization of the needle tract under lateral fluoroscopy guidance: anesthetize the skin and entire needle tract with 5–8 mL of 0.5% lidocaine (2% lidocaine diluted in 0.9% saline solution) without vasoconstrictors. Advance the needle under local anesthesia to the vertebral body surface gradually. Position the needle tip in the optimal injection area.
   NOTE: The puncture point on the skin is approximately 7–8 cm from the dorsomedial line, depending on body shape. Figure 1A shows the needle tract. Figure 1B shows the optimal injection area, which is at approximately one-third the dividing line of the vertebral body in the lateral view of a lumbar X-ray.
4. Confirmation of the accuracy of the needle position with contrast agent: after ensuring that the needle tip is in the optimal area in the lateral view of a lumbar X-ray, inject 0.5 mL of the contrast agent to further evaluate the correct position of the needle tip.
   NOTE: The goal is to keep the contrast agent mainly confined to the optimal area then spreading along the psoas major muscle. Distribution of the contrast along the psoas muscle fibers is the marker of successful injection behind the anterior fascia (Figure 2).
5. Injection of inactivating agent, 5% phenol: after aspiration, to ensure no puncture accidents, inject 2 mL of 5% aqueous solution of phenol into the optimal area (adjust the needle tip direction to ensure 1 mL of phenol spreads to the direction of the head then 1 mL of phenol to the direction of the foot). Then, withdraw the needle from the skin and compress and cover the puncture site with gauze to achieve hemostasis.
   NOTE: Steps 4.3 to 4.5 were performed at L3 and L4, respectively.
6. Evaluation of the efficacy of sympathetic interruption: define satisfactory sympathetic interruption as a rise of at least 2 °C in skin temperature 5 min after the completion of step 4.5. If satisfactory interruption is not achieved, perform supplemental injection to another optimal area or L5, with a total phenol volume no larger than 10 mL for both sides. Perform the other side in the same manner if needed. Measure the skin temperature using an infrared thermometer, and calculate the average among temperature increases in the shin, plantar, and dorsal foot.

5. Postoperative Care

1. Encourage the patient to drink water and ambulate after completion of the procedure. Check the patient on the following day for any discomfort, especially in the loin, groin, and thigh, and for improvement of symptoms and any signs of primary disease. Measure the skin temperature as described in step 4.6. Follow-up with the patient accordingly.

Results

The needle tip should be in the optimal area as shown in Figure 1. In selective CLS, the contrast is injected behind the anterior fascia of the psoas major muscle, targeting gray rami communicantes. A comparison of contrast spreading in selective CLS (A) and conventional CLS (B) is shown in Figure 2.

The expected clinical effects are vasodilation (for treatment of Rayna...

Discussion

Here we classify CLS as either conventional or selective CLS, with the major difference being the targeting of sympathetic trunk vs. gray rami communicantes (injection of phenol in front of vs. behind the anterior fascia of the psoas major muscle). We have implemented selective CLS in young, female patients with livedo reticularis¹⁰, children with erythromelalgia^7,9, and senile patients with end-stage arteriosclerosis obliterans a...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
10 cm 9# puncture needle	Peking University Third Hospital	Not Applicable	7# for children
5% Phenol diluted in aqueous solution	Peking University Third Hospital	Not Applicable	10 mL
Aseptic puncture kit	Peking University Third Hospital	Not Applicable	6 pieces of surgical towel, gauze, cotton balls, blood vessel forceps, etc.
Infrared frontal thermometer	OMRON health care (China) Co.,Ltd.	MC-720
Iodophors skin disinfectants	Shanghai Likang Disinfectant Hi-Tech Co., Ltd.	20180404
Sterile surgical gloves	Beijing Ruijing Latex products Co., Ltd.	2018070352