Background: Flexible ureteroscopy (fURS) is one of the main treatment options for urolithiasis less than 2 cm. Although fURS has no relative contraindication, some anatomical factors may need to be considered, as not all patients are suitable for the regular lithotomy position (LP). We report the case of a patient with a right iliac vascular graft that after an fURS without intraoperative incidences developed a reperfusion syndrome of the right lower limb. Case Presentation: A 46-year-old male patient was referred for treatment and follow-up in the cystinuric clinic after being found to have a 3 cm pelvic stone with a Double-J catheter in place after two failed sessions of shockwave lithotripsy. The patient was placed in the LP and a standard ureteroscopy was done with no intraoperative complications. During the first hour in the recovery room, the patient developed severe pain in the right calf muscle stiffness, edema, and increased volume. A postreperfusion and compartment syndrome diagnosis was made with emergency fasciotomy. Conclusion: To perform fURS, each case must be assessed individually. If a patient with an iliac vascular graft has to undergo fURS, the patient positioning must be modified by keeping the ipsilateral (or both) legs straight to avoid graft complications.