A Case Report on Abdominal Pain Treated With a New Technique of Ultrasound-Guided Transversus Abdominis Plane...

Hydrodissection, a technique for performing morphological dissection between the target tissues via injection, has attracted attention in recent years. However, high-quality evidence is available only for a few entrapment neuropathies, such as carpal tunnel syndrome, and further case studies are needed for other diseases. This case report presents the first case of hydrodissection of the ventral ramus of the spinal nerve, which innervates the abdominal wall, to improve abdominal pain. A 59-year-old Japanese man with a history of cerebral infarction and dyslipidemia presented to the emergency department with the chief complaint of left upper abdominal pain that began two days earlier. The pain radiated to the left side of the back and left axilla. The abdomen was flat and soft with no tenderness on examination, and the pinch test was negative. However, Carnett's sign was observed in the left upper abdomen, and the location of the left upper abdominal pain and that of the radiating pain were consistent with the ninth thoracic vertebra (Th9) dermatome; thus, the cause of the left upper abdominal pain was determined to be the ventral ramus of the spinal nerve of Th9. Two weeks of physical therapy and lifestyle guidance were ineffective; therefore, hydrodissection of the transversus abdominis plane (TAP) between the myofascia of the internal oblique muscle and that of the transversus abdominis at the Th9 level using a 23G 60 mm needle under ultrasound guidance was planned. The abdominal pain immediately improved after hydrodissection, and the patient was able to work without pain. Thus, ultrasound-guided TAP hydrodissection with a low-concentration local anesthetic is effective in the treatment of abdominal pain caused by the entrapment of the ventral ramus of the spinal nerve due to adhesions between the myofascia of the internal oblique muscle and that of the transversus abdominis. This condition should be termed ventral ramus of spinal nerve entrapment syndrome (VERNES), and this concept and TAP hydrodissection must be made known to the public.