Ultrasound-guided modified subcostal transversus abdominis plane block in a foal undergoing omphalectomy

Abstract

A 7-day-old, 60 kg, Purebred Spanish Horse filly was referred with the mare to Complutense University of Madrid, Veterinary teaching hospital for elective omphalectomy. Upon admission, clinical examination was unremarkable except for a thickening of the umbilical area. Haematology and biochemistry values were within the normal range. On abdominal ultrasound (US) examination, a well-defined, rounded (24 mm of diameter) area that contained heterogeneous material with numerous hyperechoic foci with acoustic shadowing was seen within the inner portion of the umbilical pedicle, between both umbilical arteries. Surgical correction with omphalectomy was scheduled. To provide perioperative analgesia, the transversus abdominis plane (TAP) block was considered. Under general anaesthesia, TAP block was performed in both left and right hemi-abdominal walls with a modified subcostal approach with two-site injections. A spinal needle was inserted under US guidance. During surgery, end-tidal concentration of isoflurane was maintained at 0.7%–0.9%. Surgery was completed uneventfully and no signs of nociceptive input were observed, suggesting an adequate level of analgesia. Therefore, this TAP block technique may be considered to provide analgesia for surgical procedures involving the abdominal wall in foals.