A 75-year-old morbidly obese woman with a history of chronic obstructive pulmonary disease (COPD), type 2 diabetes mellitus, and hypertension presented to the emergency department with 3 to 4 weeks of increasing right-sided flank pain and swelling without fever or chills. The patient noted a right-sided bulge in her flank. The patient was informed approximately 10 years before admission that she had a non-functioning hydronephrotic kidney that she decided to treat conservatively. She had no change in her bowel movement, no gross hematuria, and no change in urination. There was no history of trauma.
Upon physical examination, the patient was in mild distress from pain. Blood pressure, temperature, respiratory rate, and oxygen saturation were all normal. The right flank was tender to palpation. A 20-cm palpable, ballotable, and enlarged right-sided flank mass associated with a large panniculus was noted. The rest of the abdominal examination showed no other localized areas of tenderness.
A complete blood count and comprehensive metabolic evaluation was normal with a creatinine of 1.05 mg/dL. Computerized tomography (CT) revealed a right-sided severely hydronephrotic kidney that was herniated through Petit’s triangle (Figures 1 and 2).
The patient was initially treated with a percutaneous nephrostomy for pain relief. She required preoperative testing, including pulmonary function testing, for medical clearance for definitive surgery.
Two months later the patient underwent a right-sided nephrectomy with repair of the associated 18-cm hernia using a large piece of veritas mesh. The kidney could be seen herniating through Petit’s triangle (Figure 3).
The post-operative course was uneventful, and the patient was discharged on post-operative day 4 with minimal discomfort. At her routine follow-up appointment 2 weeks later, she had minimal residual discomfort with a well-healed incision and no recurrent hernia.
Although not usually a clinically significant landmark, this is a case that shows the clinical ramification of this lesser known area and allows us to revisit and relearn the anatomy.
The anatomical location of Petit’s triangle is named after Jean-Louis Petit, a French surgeon born in Paris on March 13, 1674. Petit founded and directed the Royal Academy of Surgery in Paris and served in numerous campaigns for Louis XIV’s army as the head of the military hospital at Tournay.1 He was one of the first noted surgeons to perform a cholecystectomy and mastoidectomy.2 Petit is also known for the invention of the screw tourniquet, the advancement of the circular amputation technique, and the characterization of a rupture of the Achilles tendon.1
Although it was not published during his life, Petit wrote Traite des Maladies Chirugicales, which describes the area known as Petit’s triangle.1 Abdominal hernias that protrude through an area of weakness of Petit’s triangle are referred to as a lumbar hernia or Petit’s hernia.2 Petit’s triangle was first described in 1783 in a case report of a strangulated lumbar hernia through the inferior lumbar triangle.5 Only about 300 cases of primary lumbar hernias have been reported in medical literature.3
The borders of Petit’s triangle, also known as the inferior lumbar triangle, is bounded by the latissimus dorsi posteriorly, the external oblique anteriorly, and the iliac crest inferiorly, which is the base of the triangle. The floor of the triangle is the internal oblique muscle. The contents of a lumbar hernia may consist of the colon, small bowel, or other viscera (kidney, spleen).4
A literature review noted four reported cases in the Japanese literature of a kidney herniating through Petit’s Triangle.5 This patient had an unusual presentation of a non-traumatic, large, right-sided mass with evidence of a herniated hydronephrotic right-sided kidney projecting through the margins of the inferior lumbar triangle.
Although most cases of herniation through a lumbar triangle are left sided and associated with known trauma or iatrogenic causes such as prior surgical incisions, our case was right sided and was not associated with these etiologies. Spontaneous lumbar hernias have usually occurred in patients with a history of dramatic weight loss or a chronic debilitating disease.6 Our patient was debilitated with obesity. Most lumbar hernias are acquired because of fascial and muscle weakness that develop over decades.
The imaging modality of choice for a suspected inferior lumbar hernia is a CT scan of the abdomen and pelvis.3-5 Surgical repair is recommended to avoid further complications such as incarceration, bowel obstruction, or strangulation.3,7 Details of the surgical technique that is required to repair a hernia of this type is not well described. This is the first case of a kidney herniating through Petit’s triangle in an individual with no history of surgery or trauma.