Endoscopic Modified Lothrop (Draf Type III) Procedure for a Case of Refractory Frontal Sinusitis with a Cutaneous Fistula: A Case Report

The endoscopic modified Lothrop procedure is a surgical technique used for the treatment of refractory frontal sinusitis. Herein, we present the case of a 61-year-old man who was referred to our hospital with refractory frontal sinusitis and an upper eyelid fistula. CT revealed diffuse bony thickening of the frontal sinuses bilaterally, and bony closure of the left nasofrontal duct. The endoscopic modified Lothrop procedure was performed by an outside-in approach using a CT-guided navigation system. Because of the massive hemorrhage from the drilled bone, the opening of the left frontal sinus was insufficient, and the bone surface was partially covered with a pedicled mucosal flap. The operation time was over 7 hours, and the intraoperative blood loss was 1225 mL. One month after the surgery, the patient presented with recurrent acute frontal sinusitis, and by 6 months after the surgery, the orifice of the left frontal sinus was blocked. The obstruction of the frontal sinus orifice was presumably attributable to osteitis and subsequent osteogenesis. Control of infection, adequate opening of the frontal sinus, and covering of the exposed bone with a pedicled mucosal flap are important to minimize the risk of stenosis and obstruction of the frontal sinus orifice.