Female patient, 32 years old, complains of chronic back pain, moderate and intermittent. Denies hematuria or urinary volume changes, smoking, previous surgeries and use of medications. Refers history of recurrent urinary infections. On examination the patient was in good general condition, no fever, mild pain on palpation of the left lower back. Blood pressure: 118/80 mmHg. Have normal values of urea, creatinine and clearance renal.Solicitada ultrasonography (USG) of the urinary tract - which showed hydronephrosis of the left kidney - and, later, computed tomography (CT).

Question:
Based on the clinical picture and the data obtained, what is the most likely obstructive disorder?