Percutaneous nephrolithotomy (PCNL) is a minimally invasive surgical

technique for treating complicated large renal stones. It is commonly

accompanied by intense post operative pain and discomfort. Multiple methods

like non-steroidal anti-inflammatory drugs, opioids(tramadol, morphine and

fentanyl), neuraxial block(epidural analgesia) and different regional anesthesia techniques(intercostal nerve block, para-vertebral block) have been described in

the literature for post operative pain management with variable outcomes.

Erector spinae plane (ESP) block is an interfascial blockade and consists of an injection of the local anesthetic in a fascial plane placed between erector spinae muscles and the tip of the transverse vertebral process . The anesthetic spreads over the fascial plane both in the cranial and caudal direction, also diffusing anteriorly and laterally at several levels by one dermatome per 3.4 mL of injected liquid.

Thoracic paravertebral block (TPVB) is the technique of injecting local anesthetic adjacent to the thoracic vertebra close to where the spinal nerves emerge from the intervertebral foramina. This results in ipsilateral somatic and sympathetic nerve blockade in multiple contiguous thoracic dermatomes above and below the site of injection. It is effective in treating acute 10and chronic pain of unilateral origin from the chest and abdomen. 

Aim is to compare the Duration of Analgesia between EPSB and TPVB In Percutaneous Nephrolithotomy Surgeries Using Levobupivacaine 0.25% from administration of block till the requirement of first analgesia. 

Method of collection of data.

After obtaining institutional ethical committee clearance, a comparative study will be carried in Rajarajeshwari Medical college and Hospital in Department of Anaesthesia. 

The purpose, the procedure and the risks involved with the study will be explained to the patient and an informed consent will be taken . 

50 patients of ASA 1 and ASA 2 aged between 20 and 60 years scheduled for elective PCNL surgeries will be selected based on inclusion or exclusion criteria as mentioned above. All patients will be subjected to detailed preanesthetic evaluation. Routine and specific investigations will be done as per patients clinical evaluation along with optimising with regular medication if required. Patients will be randomly allocated into two groups of 25 each by single blinded open envelope technique as follows : 

Under ultrasound guidance using, curvilinear probe 

Group E – Patients will receive 25 ml of 0.25% Levobupivacaine at T8 level (erector spinae block) 

Group PV – Patients will receive 25 ml of 0.25% Levobupivacaine at T8 level.(paravertebral block) 

All the patients will be reviewed and explained about the procedure. 

Patients will be kept nil by oral for 6 hours and will be given T.Pantoprazole 40mg T. Alpralozolam. 

On arrival of the patient to the operation theatre, monitors will be connected and base line respiratory rate, pulse rate, non-invasive blood pressure, SPO2 and ECG recorded. Intravenous line of 18G shall be secured and intravenous fluids will be started as per requirement. 

Patient in supine position with adequate preoxygenation and premedication with Inj Midazolam 0.01mg/kg and Inj Glycopyrolate 0.2mg will be induced with Inj Fentanyl 1-2mcg/kg, Inj Propofol 2mg/kg and Inj. Vecuronium 0.1mg/kg. 

After obtaining adequate muscle relaxation, laryngoscopy will be done and intubated with endotracheal tube. Bilateral airway entry is confirmed and secured appropriately. 

Patient is changed to prone position and hemodynamic parameters will be monitored throughout the procedure at regular intervals. 

At the end of surgery, under strict aseptic conditions, counting down from C7, T8 vertebra will be identified under ultrasound guidance using curvilinear probe. 

Probe will be moved until Erector spinae muscle visualised and using out of plane technique using 23G Quincke Babcock needle will be directed towards transverse process underneath fascia of Erector spinae muscle. 2-3ml of normal saline will be injected to confirm the spread following which 20 ml of 0.25% Levobupivacaine will be injected. 

Similarly in the other group, transverse process at T8 level will be visualised and the study drug will be deposited in paravertebral space between the costo transverse ligament and pleura which will be visualised as hypoechoic layer. 

The patient is changed to supine position and extubation will be done after a reversal of residual neuromuscular block with neostigmine (0.05 mg/kg) and glycopyrrolate (0.01 mg/kg) at the end of the surgery. Patients will be transferred to post anesthesia care unit to monitor hemodynamic parameters, postoperative pain, sedation, nausea and vomiting at 0,1,2,4,6,8,12,16,20,24hrs. Patients will be evaluated pain postoperatively for the duration of analgesia and pain will be assessed using a standard 10 cm linear VAS. 

Pain assessment will be done 20 minutes after extubation which will be considered as zero time. 

Total duration of analgesia will be taken from zero time till the first rescue analgesic requirement. 

When VAS score is more than or equal to 4, Inj.Paracetamol 1g will be given as rescue analgesia. Total number of doses of Inj Paracetamol 1g given in 24 hours will be noted. 

Patients will be left out of the study in case of block failures