Ilioinguinal Iliohypogastric Nerve Block as Adjunct to Spinal Anesthesia for Cesarean Section

Overview

The aim of the present controlled randomized study is to compare between ilioinguinal/iliohypogastric nerve block (IINB) and morphine as adjuncts to spinal anesthesia for cesarean section regarding quality of post-operative analgesia. The researchers will compare between the following groups: Group C, control group; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5%, Group I; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5% plus bilateral ultrasound guided IINB, and Group M; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5% plus 200 mcg morphine to answer the question: Could IINB be an alternative to intrathecal morphine during spinal anesthesia for cesarean section ?.

Ninty full term healthy non laboring parturient between 21 and 40 years of age who had normal singleton pregnancy scheduled for elective lower segment cesarean section through a Pfannensteil incision under spinal anesthesia will be recruited in the study after obtaining an informed written consent. During the preoperative visit, parturient will be explained how to use pain numeric rating scale (PNRS), post-operative nausea and vomiting (PONV) intensity scale, and Likert 4 point satisfaction scale. The participated parturients will be divided randomly using a computer generated random table into three equal groups thirty patient each; C, I, and M. Group C, control group; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5% (2.5ml). Group I; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5% (2.5ml) plus bilateral ultrasound guided IINB at the end of surgery after suturing and dressing the wound. Group M; will receive intrathecal 12.5 mg hyperbaric bupivacaine 0.5% plus 200 mcg morphine in 2.5ml solution. In the morning of surgery; all participants will be administered IV infusion of 40mg pantoprazole diluted in 500 ml of lactated ringer over 30 min. Pulse oximeter, ECG and noninvasive blood pressure will be connected to the participant on arrival to the operating room. Spinal anesthesia will be given in the sitting position under complete aseptic precaution at L3-4 or L4-5 subarachnoid space with a 25 or 27 gauge Sprotte spinal needle. Loss of Light touch sensation on the mid-clavicular line below T 7 will be considered adequate for start of surgery. Ultrasound guided IINB will be performed by scanning the anterior abdominal wall superior and medial to the anterior superior iliac spine in a line between the anterior superior iliac spine and the umbilicus using a linear probe (4-12hertz). Ilioinguinal and iliohypogastric nerves will be identified in the plane between the internal oblique muscle and the transversus abdominis muscle. After negative aspiration of blood; 20 ml plain bupivacaine 0.25% plus 4mg dexamesathone will be injected. The same technique will be performed on the other side. All parturients will be given IV acetaminophen 1g/8h and IV Lornoxicam 8mg/12h. Rescue IV 3mg morphine will be given if pain score ≥ 4 is reported during the first post-operative 24 hours. The following parameters will be recorded; demographics, vital signs, and quality of postoperative analgesia using the PNRS, ranging from 0 (no pain) to 10 (severe pain); at rest and during movement in the following time points: Time 0; end of surgery (T0), T1 (4 hours after surgery), T2 (6 hours after surgery), T3 (12 hours after surgery), T4 (18 hours after surgery), T 5 (24 hours after surgery), T 6 (36 hours after surgery), T 7 (48 hours after surgery), and T8 (72 hours after surgery), total amount of rescue morphine during the first 24h after surgery, time to first ambulation, and complications including pruritus, PONV using the PONV intensity score, sedation using Ramsey sedation score, respiratory depression (respiratory rate ≤ 8/min), and complications related to IINB as improper block, pain, hematoma or infection at the site of injection. Patient's satisfaction will be assessed 72 hours after surgery using Likert 4 point scale. A single researcher who will be blinded to groups will be responsible for all measurements and data collection.