Comparative Study of Wound Infiltration Versus Instillation Technique for Postoperative Analgesia Using 0.375 Percentage Ropivacaine in Patients undergoing Lumbar Laminectomy Surgery

This randomised comparative trial will be conducted in the Department of Anesthesiology in collaboration with the Department of Neurosurgery, Dr. S.N. Medical College and the associated group of hospitals in Jodhpur, Rajasthan, India. The study will be conducted after approval from the Institutional Ethics Committee and CTRI registration. A pre-anaesthetic check-up will be conducted for all patients; details related to clinical history, general physical examination, and all necessary investigations will be carried out. All patients will be informed about the numerical rating scale (NRS), a scale of 0-10 (0 = no pain and 10 = worst pain) [17] and will be assessed the day before surgery. All patients will be kept fasting overnight and will be pre-medicated with tablet lorazepam 0.05 mg/kg and tablet ranitidine 150 mg orally the night before surgery.

Upon arrival in the operating room, all standard ASA monitors will be applied, and baseline parameters of non-invasive blood pressure (NIBP), heart rate (HR), electrocardiogram (ECG), and peripheral oxygen saturation (SpO2) will be recorded and maintained throughout the perioperative period. Peripheral intravenous access will be obtained with an 18-G cannula, and lactated Ringer`s solution will be started. General anaesthesia will be given as per protocol.

At the end of the surgical procedure and when hemostasis was achieved, Group I (Wound Infiltration) will receive 20 ml of 0.375% ropivacaine infiltrated into the muscle layers, subfascial plane, and subcutaneous tissue around the surgical site using a 20 ml syringe before skin closure and Group S (Wound Instillation) will receive 20 ml of 0.375% ropivacaine poured directly into the surgical wound cavity after dural closure and just before skin closure. The wound will be closed in layers without mopping or suctioning. The drug solution will allow it to remain in the wound for a contact time of 60 seconds. Thereafter, the wound will be closed in layers, and no mopping or suctioning will be done. At the end of surgery, patients will be turned supine and residual neuromuscular blockade will be reversed and the trachea will be extubated when the patient is fully awake and breathing adequately, an assessment for pain will be done and recorded and will be shifted to the post anaesthesia care unit (PACU).