A CASE OF OBTURATOR HERNIA AND HIGH VOLUME ILIOINGUNINAL- ILIOHYPOGASTRIC NERVE BLOCK 1.Ehime University Graduate School of Medicine, Department of Anesthesia and Perioperative Medicine　Toon, Ehime, Japan 2.Ehime Prefectural Imabari Hospital, Imabari, Ehime,Japan Aisa Watanabe1, Kenichi Takechi2, Toshihiro Yorozuya1 Introduction Figures An obturator hernia (OH) is a rare condition with high rates of morbidity and mortality in elderly females. 1) We experienced a case of OH on which we could not perform spinal anesthesia and instead we successfully managed it with an ultrasound guided,high volume ilioiguninal-iliohypogastric nerve block. SC EO SC: Subcutaneous tissue EO: External oblique muscle IO: Internal oblique muscle TA: Transversus abdominis muscle TF: Transversalis fascia IC: Iliac crest AC: Abdominal cavity LA: Local anesthetics IO LA TA TF IC Needle Case report AC Case: A 99-year-old female (height 143 cm, weight 44 kg) Comorbidities: Congestive heart failure and mild dementia. Anesthesia Plan Plan A: Spinal anesthesia (could not perform) Because of her old age and severe comorbidities, we thought that general anesthesia should be avoided. Plan B: An ultrasound guided, ilioiguninal- iliohypogastric nerve block with dexmedetomidine sedation. Anesthesia Course Iliohypogastric nerve block: 0.5% ropivacaine 5ml (Fig.2) Ilioiguninal nerve block: 0.5% ropivacaine 20ml(Fig.3) The spreading of the local anesthetics over the transversalis was confirmed by the ultrasound image.(Fig.4) Ten minutes after the block, cold hypoesthesia in the ilioiguninal- iliohypogastric nerve area was confirmed. Dexmedetomidine (loading dose 4μg/kg/hr, 15min and maintenance dose 0.4-0.6μg/kg/hr) was injected during the operation. BIS score was maintained at 60-80 during the operation. Very small body movements were observed during surgery but they did not disturb the surgical procedure. Clear liquid that was thought to the local anesthetics was observed in the surgical site over the transversalis fascia. Total operation time was 83 minutes and the patient does not recall any memories from the surgery. Fig.1: Pre block Fig.2: Iliohypogastric nerve block EO Ilioiguninal & liohypogastric nerves IO EO Rectus muscle TF IO TF TA IC Needle LA Femoral nerve TA Psoas major muscle Gluteus muscles Iliac muscle Fig.3: Ilioiguninal nerve block Fig.4: post block Figure from Ref 2 Discussion Generally, OH is often associated with old age and comorbidities and general anesthesia should be avoided.1) An ultrasound guided, ilioinguninal-iliohypogastric nerve block is usually performed with a lower volume (0.2-0.25ml/Kg) for open during ilioinguinal hernia repair. However, because of its deep surgical site, an ilioinguninal-iliohypogastric nerve block is usually considered inadequate as the sole anesthesia for OH repair. On the other hand, in cadaveric study, local anesthetic is spread heavily on the transversalis fascia after being injected between the internal oblique muscle and transversus abdominis.2) In our case, high volume ropivacaine spread heavily over the transversalis fascia and was effective as the sole anesthesia for OH repair. References 1) Ulus Travma Acil Cerrahi Derg 2016; 22: 297–300, 2) J Korean Surg Soc 2011; 81: 408-413