All selected patients will undergo a routine preanesthetic assessment with one day prior to surgery. All patients will be explained about the blocks and study methodology, including the advantages of postoperative pain relief. The patient information sheet will be provided to all, and informed written consent from all patients will be obtained. Patients will be taught to express pain by using a 11-point NRS (Numeric Rating Scale), in which they will be asked to encircle a number between 0 and 10 that would fit best to their pain intensity other where 0 represents ‘no pain at all’ and ten means ‘worst pain ever possible’. Patient will be trained and counseled regarding functioning and operability of the PCA pump during the preanesthetic visit.

Standard fasting guidelines [American Society of Anesthesiologists, ASA] will be followed for all patients. 

All patients will be pre-medicated with Tab Ranitidine 150mg HS and CM and Tab Alprazolam 0.25mg orally the night before the day of surgery. On the day of surgery, the Anaesthesia Machine will be thoroughly checked, and the availability of appropriate airway equipment will be ensured.

In the operating room, standard monitoring as per American Society of Anesthesiologists’ recommendation

(3- lead ECG, pulse oximetry, NIBP) will be initiated and baseline vitals (Heart rate (HR), Systolic BP(SBP), Diastolic BP (DAP), Mean BP(MAP), SpO2) will be recorded. Non-invasive blood pressure monitoring will be done at every 5 min intervals till end of anesthesia care. An 18G intravenous cannula will be secured preoperatively. Patients will be allotted to one of the two groups depending on a computer-generated random number table. Allocation concealment will be ensured by enclosing assignments in sealed, opaque, sequentially numbered envelopes, which will be opened only upon the patient’s arrival in the operation room.

Induction with Intravenous (IV) Fentanyl 2mcg/kg (induction analgesic), followed by IV Propofol 2mg/kg and will be facilitated by Atracurium (0.5mg/kg).

Airway secured by ETT of appropriate size.

Anaesthesia maintained with oxygen, air and Isoflurane with target MAC of 1.0 ± 0.2.

Incremental doses of Atracurium 0.1 mg/kg will be administered accordingly.

Intraoperative fluid protocol will be decided by the attending anaesthesiologist and amount of intraoperative fluid (crystalloid, colloid, blood and blood products) will be noted. Patients will receive balanced salt solution-Ringer’s lactate or Plasmalyte as initial intravenous fluid. Colloids like hydroxyethyl starch are started at the discretion of the attending anaesthesiologist. Total amount of crystalloid and colloid used will be noted. 

Patients will also receive ephedrine boluses to maintain MAP within 10% of baseline. The total ephedrine doses received by the patient will be noted.

After induction, all patients will be made prone.

After making patients prone both eyes and all pressure point will be taken care off.

( Post induction) Randomisation will be done - all patients will receive either USG guided TLIP block or USG guided sacral ESPB as per their allocated group after randomisation.

Group T - USG guided TLIP block will be given in between multifidus and longissimus muscle 

Group S - USG guided sacral ESP block will be given at intermediate crest 

Intraoperatively if HR and MAP increase > 20%, fentanyl 0.5mcg /kg will be administered. Paracetamol 15mg/kg will be given 30-45 min before the end of surgery, Ondansetron 4mg will be given 30min before the end of surgery.

Classical TLIP block:

·       After making the patients prone.

·       Skin will be sterilised with 2% chlorhexidine. 

·       A sonosite S- nerve ultrasonography machine (FUJIFILM sonosite Inc, USA) with low frequency 5-2Hz curvilinear probe was placed transversely at the particular vertebral level in the midline and adequate depth of 3-8cm was adjusted on USG screen.

·       After identification of the corresponding spinous process and paraspinal muscles namely Multifidus, longissimus and iliocostalis from medial to lateral under real time ultrasound guidance, a 10cm  21G Stimuplex needle was inserted in plane in a lateral to medial direction, at an angle of approximately 30 degree to the skin and advanced towards the multifidus muscle through the belly of longissimus muscle. As the needle tip reaches the longissimus/multifidus interfascial muscle plane close to superior articular process, confirmed by hydrodissection a total volume of 15ml of 0.25% Ropivacaine + 4mg of dexamethasone will be administered with intermittent negative aspiration. The remaining 5ml of drug will be administered below the ipsilateral thoracolumbar fascia. The same procedure will be repeated on the contralateral side.

Sacral ESP block

·       The patient is made to lie in prone position. 

·       Under AAP, in prone position, linear probe/curvilinear 5-12Hz will be placed longitudinally in the midline above sacrum just above the median crest.

·       The first median sacral crest will be visualized as hyperechoic shadow with the overlying hypoechoic latissimus dorsi muscle.

·       The probe will be moved laterally to identify the intermediate sacral crest, the dorsal sacral foramina, longissimus thoracic muscle, and multifidus muscle.

·       After optimizing the image at S1 level a 21G 10cm needle Stimuplex will be advanced in plane approach hitting the underlying bone.

·       Following negative aspiration, 20ml of drug (0.25 % Ropivacaine + 4mg dexamethasone) will be injected under the multifidus muscle and over the hyperechoic bony area at intermediate sacral crest 

·       The craniocaudal spread of the LA with the separation of multifidus muscle from the underlying one was noted during the injection. 

·       The same procedure will be performed on contralateral side 

·       Hence, a total 40ml of LA - 0.25% Ropivacaine will be used for intervention along with 8mg dexamethasone.

At the end of the surgery, residual neuromuscular blockade will be reversed by IV neostigmine 50-70 mcg/kg and glycopyrrolate 7-10mcg/kg. All patients will be extubated once they fulfil criteria for extubation. All patients will be transferred to the post anaesthesia care unit (PACU).

After shifting the patient to the PACU, a PCA pump will be connected to the IV line in all patients. The drug used in PCA will be fentanyl with a concentration of 10 mcg/ml. It will be programmed to deliver 20 mcg boluses of fentanyl per press with a lockout interval of 15 mins without baseline infusion and a maximum dose of 300 mcg to be delivered in 4 hours period. In addition, all patients will be administered IV PCM 1 gm every 6 hourly.

Postoperatively, patients will be managed in the postoperative care unit where standard monitoring of oxygen saturation (SpO2), heart rate (HR) and non-invasive blood pressure monitoring is done every 10 minutes till 1 hour and then will be shifted to PACU.  

All patients will receive humidified oxygen through face mask at 5L/min.

The NRS scores will be noted at 30 minutes, 2 hours, 4 hours, 6hours, 12 hours and 24 hours, separately at rest & on movement.

Paracetamol 1g IV given 6th hourly to all patients in both the groups for 24 hours.

Gabapentin 300mg tablet will be given orally before bedtime.

In the immediate postoperative period if the patient complains of NRS pain score more than 4, intravenous boluses of 25mcg Fentanyl will be given to reduce the NRS pain score to less than 4.

After that, further analgesia will be provided whenever NRS pain score is more than 4 via the PCA pump. 

The time to first analgesic requirement will be noted from the PCA pump.

PCA will be programmed as a 25mcg bolus and 15min lockout time with no basal infusion and maximum 4 hourly dose of 400mcg and will be maintained for 24hrs.

In case pain relief is inadequate, it will be managed with Intravenous boluses of 25mcg Fentanyl

Fentanyl consumption at 2 hours, 4 hours, 8 hours and 24 hours and cumulative Fentanyl consumption is noted. 

Presence of any other adverse event related to intervention (local hematoma, motor weakness, urinary retention) and opioid consumption (PONV, respiratory depression) is noted.

Intravenous Ondansetron 4 mg will be given to every patient 8 hourly in the post operative period.

The number of episodes of PONV will also be noted for the first 24 hours. The PONV scoring will be done at 0mins, 30mins, 2 hours, 4hours, 8hours, and 24 hours.

PONV SCORING:

0: no nausea or vomiting

1: nausea but no vomiting

2: vomiting once in 30minutes

3: two or more episodes of vomiting in 30minutes.

At the first episode of nausea or vomiting, patient is counseled for it being a common side effect of opioid administration. In case of inadequate relief or any further episode, it will be managed with IV metoclopramide 10 mg given slowly over 15minutes.

Patient satisfaction with the technique will be assessed 24 hours after the operation on an 11-point patient satisfaction score.

0-unsatisfied, 

10-most satisfied.

 QoR 15 (Quality of Recovery) will be used to evaluate the patient’s emotional state, physical comfort, psychological support, physical independence, and pain status. It will serve to assess the quality of recovery after anaesthesia and patients’ health status in post operative period.