Excessive intraoperative hemorrhage during orthognathic surgery in a patient with neurofibromatosis type 1: a case report and literature review

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder caused by NF1 gene mutations, resulting in neurofibromin deficiency and vascular fragility. Although excessive hemorrhage during surgery has been reported in patients with NF1, such complications during orthognathic surgery are extremely rare. A 26-year-old woman with NF1 presented with skeletal Class II malocclusion. Preoperative contrast-enhanced computed tomography and magnetic resonance imaging revealed no neurofibromas along the airway or near the surgical field. Le Fort I osteotomy and bilateral sagittal split ramus osteotomies were planned following orthodontic treatment. Considering the bleeding risk associated with NF1, 600 mL of autologous blood was collected preoperatively. During surgery, persistent diffuse microvascular bleeding occured without identifiable vessel injury. The total intraoperative estimated blood loss was 1,715 mL, approximately five times higher than the average value reported for combined Le Fort I osteotomy and bilateral sagittal split ramus osteotomies. Hemostasis was achieved using oxidized cellulose compression. The patient received autologous blood transfusion only and recovered without allogeneic transfusion. Postoperative hemoglobin improved gradually with oral iron therapy, and the patient was discharged on postoperative day 16 without further complications. This case highlights the potential for excessive hemorrhage during orthognathic surgery in a patient with NF1, even in the absence of apparent neurofibromas. Comprehensive preoperative vascular assessment and autologous blood preparation are essential. Surgeons should be prepared for prompt hemostatic management to ensure safe surgical outcomes in patients with NF1.