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Identifying Caput Medusae during Transversus Abdominis Plane Block
Session: MP-10a
Sat, April 21, 10:15-11:45 am
Shubert (Shubert Complex), 6th floor

Please note, medically challenging cases are removed three months after the meeting and scientific abstracts after three years.

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Title:  Identifying Caput Medusae during Transversus Abdominis Plane Block

Authors: Brandon Hammond, MD, Bryan Whitlow, MD, Nicholas  Haralabakis, MD


The transversus abdominis plane (TAP) block is a well-described adjunct in controlling postoperative acute pain from abdominal surgery. In addition to the general risks of regional anesthesia, the TAP block also carries the risk of intraperitoneal injection, intravascular injection and possible liver trauma if ultrasound is not utilized.1 When attempting this block in a patient with liver disease, anesthesiologists should have a high suspicion for portal hypertension resulting in caput medusae, and extreme care must be taken to avoid intravascular injection, or vessel laceration and hemorrhage.   


TAP blocks at our institution are typically placed using a 4-inch 21-gauge echogenic needle under ultrasound guidance.  Abdominal wall muscle layers are identified with ultrasound and local anesthetic injection visualized between the internal oblique and transversus abdominus muscles along the mid-axillary line inferior to the subcostal margin bilaterally. Patient informed consent was obtained for submission of this case report.

Case Report:

A 67-year-old male with a history of hepatitis C, cirrhosis, grade 2 esophageal varices status post banding, hepatocellular carcinoma, and chronic pain was admitted for laparoscopic radiofrequency ablation of an intrahepatic lesion. The lesion could not be successfully ablated due to the inability to safely access the nodule and the procedure was aborted.  Following uneventful emergence from anesthesia and transfer to the PACU, the patient experienced severe post-operative pain.  We then evaluated the patient for a potential TAP block. A review of the patient’s preoperative laboratory results was significant for moderate thrombocytopenia with platelets of 72,000, INR of 1.25 and hemoglobin of 13 g/dL. There was no mention in the medical record of caput medusae nor was this appreciated on our physical exam.  The TAP block was successfully performed on the right side without incident.  When repeating the procedure for the left abdominal wall, numerous engorged vessels were visualized on ultrasound traversing all muscle layers from the umbilicus to the mid-axillary line. The surgical team was called to the bedside and attested that the findings were consistent with previously undescribed caput medusae. The ultrasound was repositioned until an area along the axillary line was identified to safely inject local anesthetic while minimizing the risk of intravascular deposit or injury.  The patient tolerated the procedure well with no complications and reported significant alleviation of pain.


A literature review did not identify any published cases of hemorrhage or local anesthetic toxicity from inadvertent vessel laceration or injection when attempting this approach in a patient with caput medusae. The use of regional anesthesia, particularly the TAP block, is recommended in postoperative pain management for patients with liver disease.2 However, anesthesiologists must pay close attention to the patient’s coagulation status and other sequelae of cirrhosis while also having intricate knowledge of the abdominal vascular territories. Engorged periumbilical veins extending across the abdomen, as well as superior and inferior epigastric vessels, should be identified and avoided, particularly if utilizing a modified subcostal transverse (oblique) TAP block approach.3   


1      Taylor R, Pergolizzi JV, Sinclair A, et al. Transversus abdominis block: clinical Uses, side effects, and future perspectives. Pain Practice. 2013: 13(4): 332-344.

2      Vaja R, MxcNicol L, Sisley I. Anesthesia for patients with liver disease. Continuing Education in Anaesthesia, Critical Care & Pain. 2010: 10(1): 15-19.

3      Ho AM. Hemorrhagic shock after minor laparoscopic procedures. Journal of Clinical Anesthesia. 2015:27: 416-418.

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