Radiofrequency thermocoagulation connected with anhydrous ethanol (AE) chemical blockade of the Multi-segmental Lumbar Sympathetic Ganglia was safe and effective. However, larger trials for better understanding of the detailed underlying analgesic mechanisms are still required.   

Along with the significant improvement in the quality of life, the incidence of diabetes is also increasing. The global prevalence of diabetes is expected to reach 552 million by 2030, suggests recent data on epidemiology. The rise in the incidence of diabetes leads to an increase in the rate of its complications. Diabetic neuropathy is one of the most common complications of diabetes. Diabetic neuropathy constitutes about 50% while painful diabetic peripheral neuropathy (PDPN) accounts for 13-26% of the total burden of diabetes. Cost-effective treatment methods for PDPN are required as its management is difficult and significantly impairs the QoL of patients. The various targets for management approaches of PDPN are 2-6 pairs of lumbar sympathetic ganglia (LSG). L2 and L3 LSG inhibition is related to the blockade of sympathetic fibres of the lower extremities and dilation of blood vessels. In this process of repression, L2 ganglia play an integral role and the location of LSG also differs. The L2 sympathetic ganglia are located in the upper one-third of the L3 vertebrae and lower one-third of the L2 vertebrae. Due to this varied location, a multi-segment treatment targeting the specific areas is required. Surgical and chemical sympathectomies are the types of traditional LSG blockades. Surgical sympathectomy results in tissue damage and trauma. Chemical sympathectomy, primarily due to drug diffusion, may harm the surrounding vital tissues and organs.

Radiofrequency therapy constitutes two methods:

1. Radiofrequency thermocoagulation
2. Pulsed radiofrequency

Radiofrequency thermocoagulation lumbar sympathectomy targets the nerve tissue by increasing the temperature and has been shown to be another effective treatment approach. Due to increased temperature, the unmyelinated nerve fiber C-axis axons get dissolved and become necrotic. It generates significant pain relief by increasing peripheral blood flow, maintaining a state of vasodilatation in lower extremities and by improving symptoms like numbness which are caused by nerve injury of lower limbs. However, the validity of punctured target selection is difficult, and the range of ablation is limited. Comprehensive treatment approach is required for PDPN management.

Rationale behind research:

The previous studies have indicated the use of single chemical or single radiofrequency treatment approaches for destroying LSG, but there is a lack of studies that examine the combination of chemicals and radiofrequency for PDPN. The present research was conducted to fulfill this great area of unmet need.

Objective:

The present research investigated the effectiveness of a combination of anhydrous ethanol (AE) chemical blockade of LSG and radiofrequency thermocoagulation for PDPN treatment. 

Study outcomes:

• Patient demographic characteristics were studied at baseline
• Other outcomes studied were necessary preoperative conditions, visual analogue scale (VAS), the total remission rate (TRR), skin temperature (ST) and the improvement of numbness and hyperalgesia in the lower extremities, complications, and degree of satisfaction (DOS) before and after surgery 

Time Points: 1M, 3M, 6M, and 1Y 



Outcomes:

Baseline: There were no significant differences observed at baseline

Study outcomes:

• There was a considerable decrease seen in postoperative VASs compared to preoperative VASs in all groups 
• There was an increase observed in VAS scores in group A after three months, in group B after six months when compared with VAS scores in other groups at three months (3M), six months (6M) and one year (1Y)
• There were significant differences observed in TRR in group C as compared to groups A and B. TRR in group A, group B and group C at 1Y after an operation was 66.7%, 73.3% and 93.3%, respectively (Fig:2)

• There were no significant differences observed in higher ST in the lower extremities after surgery in all the groups compared to peroration (P<0.05)
• There was an improvement in the incidence of the numbness and hyperalgesia in all three groups after surgery compared to preoperational time. In group C, the degree of numbness was significantly higher as compared to other groups (groups A and B). No severe complications were observed.
• The degree of satisfaction was higher in group C as compared to groups A and B at a period of 6M and 1Y after surgery

The results of the study found that in the AE group, pain symptoms repeatedly appeared after 3M, steadily becoming worse with the passing time. These results were consistent with the studies reported by Jackson and Gaeta, and it might be related to the regeneration of nerves using the AE. There was a significant reduction in the prevalence of complications under visual guidance. However, the lateral femoral cutaneous nerve or genitofemoral nerve may get permanently damaged due to the variability of damage agent and neural pathway resulting in acute renal failure in serious cases. In this study, there were four cases of genitofemoral nerve damage. After conservative therapy, all four cases were resolved. The maintenance of pain relief for a short period and a higher incidence of complications restrict the use of CLS.

Accurate target position for puncture, clear images, confirming the location of needlepoint position and scanning are few benefits linked with the CT-guided radiofrequency thermocoagulation of LSG. It also helps to prevent the occurrence of complications and can also be performed frequently. Although, there are high requirements for accuracy of nerve target the number and location of lumbar sympathetic ganglia mainly vary with the absent division of sympathetic stem and communicating branches. It can cause incomplete nerve ablation, where the location, action duration and temperature affect the degree of ablation. So, there is no stability in the effect of simple radiofrequency ablation of LSG.

In this study, the radiofrequency group experienced lower analgesic effect in the early stage as compared to the combination and AE group. Analgesic effect for up to 1 year and its 1-year total effective rate was significantly better in the combination group (group C) than the other two groups. As compared to group A and B, the group C showed high remission rate of numbness symptoms in the late stage. No significant change in skin temperature was noted. Previous studies have indicated that disturbance of lumbar sympathetic nerve cells can control the regeneration of cutaneous vascular cells due to increased expression of angiopoietin-1 and inhibition of the proliferation of parietal cells and. It can also reduce the inflammatory reaction in the sympathetic nerve denervation area, decrease the adrenergic release in the dorsal root ganglion, inhibit sympathetic activity by stimulating α2-adrenergic receptors and upregulating α2-adrenoceptors,31 inhibit spinal microglia activation and reduce the expression of inflammatory cytokines (IL-1β, IL-6, and TNF-α). That is why the complex mechanisms of sympathetic nerve blockade inducing pain relief requires further studies for better understanding. At last, it can be concluded that radiofrequency thermocoagulation blockade of LSG with multi-segmental AE provide effective pain relief with subsequent reduction in the complications.