A Randomized Case Control Study of Pre-emptive Caudal Epidural Analgesia With Ropivacaine With and Without Dexamethasone for Lumbosacral Spine Surgery

Lumbosacral spine surgeries are commonly performed under GA. Perioperative pain following spine surgeries not only contributes to significant morbidities but also hampers early mobilization. Perioperative opioids, though relieve pain but hampers consciousness, increase PONV and delays mobilization. Caudal analgesia can be effectively given preemptively to alleviate pain and facilitate early mobilization. Caudal epidural block places the needle through the sacral hiatus into the epidural space to deliver medications. It can be performed as ultrasound guided procedure with very high successful rates. Single shot caudal block with local anesthetic provides analgesia for 2-4 hours but this can be further prolonged by adding adjuvants like opioids, steroids, ketamine, alpha 2 agonists, adrenaline etc. Ropivacaine is a long-acting amide local anesthetic agent which is less lipophilic, less cardiac and central nervous system toxicity with similar duration of analgesia, has lesser motor blockade and facilitates earlier mobilization than bupivacaine. Dexamethasone is a highly potent, long acting glucocorticoid. Caudal dexamethasone prolongs the analgesic duration of the ropivacaine. The aim of this study is to evaluate the role of pre-emptive caudal epidural analgesia for postoperative pain relief in lumbosacral surgeries and to compare the effect of adding dexamethasone to ropivacaine with respect to quality of analgesia, duration of analgesia, hemodynamic effects and associated side effects.

Patients will be allocated in one of the two groups, I and II, consisting of 30 each, using a lottery based random number. A box containing 60 chits, with 30 labelled as group I and other 30 as group II, will be given to each patient and will be asked to take out 1 chit. The group allocated will be written in separate paper by an anesthesiologist, who will also prepare drugs. Decoding will be done later after completion of all data collection. The patient in Group I will be given caudal epidural injection with 0.25% ropivacaine 20 ml containing dexamethasone 8 mg (0.5% Ropivacaine 10 ml + 8 mg/2 ml Dexamethasone + 8 ml NS) and group II will be give 0.25% ropivacaine 20 ml. All the data collection will be done by another anesthesiologist, not involved in group allocation, drug preparation and administration.

At preoperative visit, all patients will be made familiar with VAS score for pain assessment and will be recorded. At operation theatre, standard American Society of Anesthesiologists (ASA) monitoring, including electrocardiography, noninvasive blood pressure, pulse oximetry and endtidal carbon dioxide, will be applied and measured. Patient's vitals will be recorded at preinduction, induction, postintubation, after caudal injection, time of incision, and at 15 min intervals till half an hour after completion of surgery. Intravenous (IV) line will be secured, and inj. Ringer Lactate (RL) 500 ml will be administered. Anesthesia will be induced with inj. Midazolam 0.04 mg/kg, inj. Fentanyl 2 mcg/kg, inj. Propofol in titrated dosages till loss of consciousness and inj. Rocuronium 0.6 mg/kg to facilitate intubation. The time of induction will be noted. After intubation and securing airway, foley's catheterization of bladder will be done and patient will be positioned in prone position for surgery in which caudal epidural injection will also be given. After painting and draping, ultrasound guided visualization of sacral hiatus will be done. In longitudinal view, using in plane technique, 22 gauge Quincke's spinal needle will be inserted below sacrococcygeal ligament. After negative aspiration of blood and CSF, epidural space will also be confirmed by injecting 3 ml of normal saline. The prepared study drugs will be injected. The time of caudal drug administration will be noted. The surgical incision will be allowed after 20 minutes of injecting drugs in both groups, to allow fixation of drugs. The time of surgical incision will be noted. Anaesthesia will be maintained on oxygen, isoflurane and intermittent boluses of muscle relaxants. Inj. Paracetamol 1 g and inj. Diclofenac 75 mg will be given intravenously, around 1 hour before anticipated completion of surgery. Neuromuscular blockade will be reversed with inj. Neostigmine 0.05 mg/kg and inj. Glycopyrrolate 0.01 mg/kg. Patients will be extubated after return of consciousness and muscle power, and will be shifted to post-operative ward. VAS score will be recorded at immediate postoperative period, 4, 8, 12 and 24 hours. All patients will be given inj. Paracetamol 1 g 8 hourly and inj. Diclofenac 75 mg 12 hourly as an intravenous infusion. If any patients have VAS ≥ 4 at any time, rescue analgesia in form of inj. Pethidine 50 mg with inj. Promethazine 25 mg will be given intramuscularly. The time to demand of first dose of supplemental (rescue) analgesic medication will be recorded. Any complications and adverse drug reactions will be recorded.