Supplementary Material for: Portable Percussive Massage Device-Related Rectus Sheath Hematoma and Obstructive Uropathy: A Case Report

Introduction
Rectus sheath hematomas (RSHs) can occur from the rupture of the epigastric arteries, leading to blood accumulation within the rectus abdominis sheath. Herein we report the unique case of a RSH resulting in acute ureteral obstruction, which was associated with the use of a handheld deep-tissue percussive massage device in attempts to relieve abdominal pain.

Case Report
A morbidly obese man in his late 50s was admitted with complications of COVID-19, including acute respiratory syndrome, bilateral peroneal deep vein thromboses, and acute kidney injury. He was treated with anticoagulants (subcutaneous enoxaparin and apixaban), dexamethasone, and remdesivir. He developed severe abdominal pain, and a large (14 x 17 cm) right rectus sheath and an extraperitoneal pelvic hematoma were identified by computed tomography (CT). The hematoma extended across the midline into the left pelvis and the retroperitoneum with associated mild right hydronephrosis. A handheld percussive massage device (Theragun®) was applied repeatedly at the site of enoxaparin injection into the abdominal wall in attempts to alleviate the pain. On day 12, bilateral nephrostomy tubes were inserted. A nephrostogram revealed mild hydroureteronephrosis to the ureterovesicular junction bilaterally and extrinsic compression of the bladder. On day 17, the patient suffered a cardiac arrest and died.

Discussion/Conclusion
This case report offers insights into the pathophysiology of obstructive uropathy and is a reminder of the importance of considering uncommon causes of obstructive uropathy in the diagnosis and management of AKI, particularly in hospitalized patients receiving anticoagulation. We know of no previous reference of obstructive uropathy caused by retroperitoneal hematoma associated with the use of a portable massage device applied to the abdominal wall.