Delayed hypersensitivity reaction to Floseal after anterior cervical discectomy and fusion surgery: a case report and review of the literature.

Introduction: Allergic reactions against the hemostatic agent Floseal during or after spine surgery are very rare, with six cases reported in the literature so far. We present a case of type IV hypersensitivity reaction against Floseal after an anterior cervical discectomy and fusion surgery. We also review the literature of reactions against Floseal for patients who have undergone spinal surgeries. Presentation of case: A 25-year-old male patient was admitted to our center with images revealing a C5 teardrop fracture and rupture of the upper and lower discs. C5 corpectomy was performed successfully without any intraoperative adverse events. On the morning of the third day post-op, the patient developed respiratory distress accompanied by swelling beneath the surgical wound. We performed an urgent exploration of the wound and evacuation of the collection. The collection was watery and clear with Floseal remnants visible. Histopathological analysis of the fluid revealed no evidence of infection but showed inflammatory changes with leukocytosis. Symptoms resolved after the second surgery and the patient recovered with no further complications. Discussion: The delayed onset of localized swelling following surgery and rapid resolution after irrigation and removal of Floseal remnant particles is highly suggestive of a delayed-hypersensitivity reaction to Floseal. Delayed-hypersensitivity reaction should be considered in the differential diagnosis of delayed post-op swelling where Floseal was used. Conclusion: We believe this is the first reported case of delayed-hypersensitivity reaction to Floseal, which occurred after anterior cervical discectomy and fusion surgery.