Following approval From the Institutional Ethics Committee, a double blinded RCT will be carried out on 60 patients presenting with features suggestive of Acute Zoster to pain and palliative care OPD, referred from dermatology OPD in JSS Medical College and Hospital. A thorough medical history from the patients will be obtained, starting from name, age, sex, occupation and then proceeding to their chief complaints, history of presenting illness and risk factors. Pain history regarding onset, duration, site and character of pain along with its aggravating and relieving factors will be documented. Psychological changes due to the pain will be noted. Pain will be assessed based on QOL and NRS. Previous treatments, significant medical history and personal history will be taken as well. General physical examination of the patient, vitals with height and weight will be recorded. Local examination of the skin lesions will be done. Patients assessed eligible for the study will be informed about the procedure. Informed and written consent will be taken, and then be assessed pre anesthetically and with investigations of CBC, Serology, CBG, PT INR etc. While patient is still on their respective treatment protocol as directed by dermatologist, the patients will also be taken for the study as per randomization. They will be divided into 3 groups in accordance with randomization

Group 1: Group intervened with ESPB (Erector Spinae Plane Block)

Erector Spinae Plane Block

It is performed by injecting local anesthetic in the plane between the erector spinae muscle and the transverse process at the spinous level corresponding to the affected dermatome. With the transducer fixed over the targeted Transverse Process (TP), needle insertion site is identified and aligned with the long axis of the ultrasound beam and approximately 1–2 cm away from the probe. The insertion site can be cephalad or caudal to the probe, as the TP can be approached from either direction. After sterile preparation, Local Anesthetic skin wheal is placed at the insertion site using a 25–27 g needle. Then needle is inserted (e.g. 23 G Quincke’s spinal needle) through the skin wheal and advanced at a 30–45-degree angle towards the ultrasound beam. The needle is advanced with in-plane ultrasound guidance to the posterior surface of the targeted TP. The operator may feel â€œfascial clicks” corresponding with the fascia of the trapezius, rhomboid (for blocks at T7 and higher), and erector spinae muscles with a final firm end point upon contacting bone. Once the needle tip is in the ESP below the erector spinae muscle, alternating aspiration (to confirm lack of inadvertent vascular puncture) with injection of small aliquots of LA or NS is recommended. Anechoic fluid should be seen separating the erector spinae muscle from the TP, confirming spread within the ESP. Once satisfied with the needle position, LA is gradually injected until a total of 20–40 mL is deposited within the plane.

Post procedure, patients will be prescribed rescue analgesia to be taken only if necessary.

Group 2: Group intervened with TPVB (Thoracic Paravertebral Block)

Thoracic Para Vertebral block 

Paravertebral block (PVB) provides analgesia by injecting local anesthetic in a space immediately lateral to where the spinal nerves emerge from the intervertebral foramina. The best strategy is to start the scanning process 5-10 cm laterally to identify the rounded ribs and parietal pleura underneath. The transducer is then moved progressively more medially until transverse processes are identified as more squared structures and deeper to the ribs. Too medial transducer placement will yield image of the laminae, at which point the transducer is moved slightly laterally to image transverse processes. Once the transverse processes are identified, a needle is inserted out-of-plane to contact the transverse process and then, walk off the transverse process 1-1.5 cm deeper to inject local anesthetic. While the position of the needle tip may not be seen with this technique, an injection of the local anesthetic will result in displacement of the parietal pleura. A pragmatic needle insertion 1-1.5 cm past the transverse may be safer than using spread of the injected to displace the pleura as the end-point.

Post procedure, patients will be prescribed rescue analgesia to be taken only if necessary.

Group 3: Group with no interventions (Control)

This group of patients will be counselled about continuing the treatment as instructed by the dermatologist initially and prescribed rescue analgesia to use when needed.

Pain relief assessment and monitoring progression to Post herpetic neuralgia will be done by repeated follow ups of patients based on reduction in symptoms of pain, QOL and NRS on day 0, 15, 30 and 60 post block procedure and the need for rescue analgesia during the study period. Each visit and follow up will be documented and results tabulated and analyzed at end of 60 days.