Study of Chemical Neurolysis, Radiofrequency Ablation and Combined Radiofrequency with Chemical Neurolysis of Lumbar Sympathetic Ganglion in Peripheral Vascular Diseases of the Lower Limbs

available for the of Abstract Background: Peripheral vascular diseases (PVDs) associated with atherosclerosis, hypertension, diabetes, thromboembolism, chronic regional pain syndrome or Berger’s disease, presents with ischemic manifestations of cold limbs, claudication, ulcers, or gangrene. Chemical lumbar sympathetic block (LSGB) with alcohol/ phenol and radiofrequency ablation (RF) are well-established methods to improve the circulation. Methods: We conducted prospective observational study in 150 cases of PVDs who underwent chemical LSGB using 5ml of phenol 8% at two levels L2 and L3 under guidance of fluoroscopy (Group CH, n=50), RF ablation of lumbar sympathetic ganglions at L2 and L3 level (Group RF, n=50) and combined RF with chemical LSGB using phenol 5ml 8% at L2and L3level following RF(Group RF+CH, n=50). Results: There was significant difference in VAS scores at six months of follow up in Group CH Vs Group RF+CH and Group RF Vs Group RF+CH, (mean VAS 2.2 in Group CH, 1.94 in Group RF & 1.26 in Group RF+CH,P <0.001) The mean WD improved significantly at six months in Group RF and RF+CH when compared with Group CH (P<0.001). At six months the temperature rise in affected limb/toe noted was 2.6 in Group CH, 2.76 in Group RF and 2.76 ̊C in Group RH +CH, it was significant for Group CH Vs RF+CH, P<0.05. Conclusion: We observed significant reduction in VAS score, increase in WD and rise in temperature of the limb in all the groups, but longer lasting effects seen in combined technique in Group RF+CH as compared to sole RF or chemical LSGB.


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Surgical sympathectomy causes lot of trauma and tissue damage, chemical sympathectomy may harm surrounding vital tissue due to drug diffusion but still popular method of neurolysis.
LSGB with local anaesthetics (LA) or with adjuvants like alpha 2 agonists clonidine, opioids, NMDA receptor antagonist ketamine, steroids or Botox are used to prolong the pain-relieving effects.
A diagnostic LSGB with LA followed by neurolysis of lumbar sympathetic chain is safe and useful method over invasive operative procedure [1,2]. During1930s-1950s chemical lumbar sympathectomy was widely used in treating occlusive arterial disease of the lower limbs as an alternative to amputation [3].
Sympathetic denervation results in increased blood flow, improves the collateral circulation and nutritive value of blood flow and thus decreases the pain transmission. [4,5] Currently RF ablation of LSG is safe and effective option that is gaining popularity for lesser incidence of complications but have concerns of high cost and availability. There are reports of the use of combined methods in the literature but very few studies are available [6,7]. We aimed to study and compare the efficacy of three techniques of LSGB i.e. chemical neurolysis, RF ablation and combined RF +chemical LSGB in successive 150 patients of PVDs. The primary outcome variables for the study were improvement in VAS score, WD and rise in temperature of the affected limb with secondary outcome to assess for immediate and late complications and progress in the wound healing up to six months proposed treatment.

Material & Methods
After obtaining Institutional review board permission and Procedure was performed in prone position and a pillow was placed below the abdomen to obliterate the lordosis. As described by Reid and co-workers [8] we followed the single needle technique of LSGB at L2 or L3 vertebral level in prone position. Under aseptic precautions LA infiltration was given just above or below the tip of transverse processes i.e. for lateral approach at 6-8cm away from the midline at level of L2 or L3.A22 G 15cm long spinal needle was

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Three such lesions were carried out by advancement of the tip for 2-5 mm. After initial RF treatment at L2-L3 level chemical neurolysis of LSG with 5ml 8% phenol was carried out at each level.
Later half ml of air injected before removal of the needles and prone position maintained for half an hour. Post block sensory and motor functions were checked after each block in all the patients of LSGB.
Radiofrequency therapy has two modes pulsed radiofrequency and thermocoagulation which targets nerve tissue by increasing temperature where unmyelinated C nerve fibres get dissolved and become necrotic resulting in vasodilatation in lower extremities and long-term pain relief improves numbness of neuropathies.
However, accuracy of targeted structure is extremely difficult, and range of ablation is limited [12,19]. Manjunath et al [13] conducted a pilot study on 20 patients of CRPS type-I to compare the chemical neurolysis with 7% phenol and RF lumbar sympathectomy.
Significant pain relief was present in both the groups without significant difference in mean pain scores between the groups [13]. Singh  Index TcPO 2 at 42 C /TcPO 2 at 45 C as an index of vasomotor tone was measured in normal, ischemic limb and after cooling the limb and concluded that TcOP 2 can be used to assess the degree of vasomotor tone in the skin that increases as ischemia worsens.
Warmth improves the cutaneous circulation in ischemic limbs [27] Angiography has been used but difficult to predict the response.
Doppler ultrasound can determine the pressure in the thigh and ankle. Ankle systolic pressure above 60mmHg and ABI >0.3 and patency of superficial femoral artery found to be successful predictive test.
High correlation is observed between ABI and TcPO 2 .
Transmetatarsal TcPO 2 <30mmHg may result in amputation [28].The patients suffering from CRPS who are refractory to conventional treatment or chemical/ RF ablation, spinal cord stimulation is recommended to improve pain and dysfunction [29]. With the introduction of ultrasound (USG) many benefits were not significantly different in two groups although procedural time was longer with USG technique, but onset time was faster. [30] The newer modalities like spinal cord stimulation or surgical revascularization are claimed to better outcomes but at present very costly and beyond reach of many centres [31]. limitation of the study by Explanation: The chemical neurolysis and RF are established techniques, so this prospective observational study was conducted. As the availability of radiofrequency machine was not sure hence, we could not randomize the patients for three different

Conclusion
We observed significant reduction in VAS score, increase in WD and rise in Temp. of the limb in all the groups, but longer lasting effects seen in combined technique i.e.in Group RF+CH as compared to sole RF or chemical LSGB. The course of the disease was similar and satisfactory in all the groups.