Iatrogenic superficial siderosis with the Pseudomeningocele after spinal surgery: a report of four cases and literature review

Superficial siderosis (SS) is an uncommon condition resulting from chronic bleeding into the subarachnoid space. The hemosiderin deposition on the brain surface and spinal cord causes the progression of neurological symptoms. Although some reports have described the occurrence of SS following iatrogenic dural injury during spinal surgery, the pathophysiology of hemorrhage remains unclear. Here we describe in detail four cases of SS that resulted from pseudomeningocele formation at the surgical site due to iatrogenic dural injury during previous spinal surgery. MRI revealed pseudomeningocele eroding the vertebral bodies in each case. Out of the four patients, two underwent surgery. A significant dural defect was detected in both patients, exposing the bone marrow in the vertebrae within the pseudomeningocele. Additionally, microscopic examination revealed bleeding from the bone marrow in the pseudomeningocele. We employed fat or muscle fascia to surgically repair the dural defect, and applied bone wax directly to the exposed bone marrow of vertebrae. These findings indicated that the inadvertent occurrence of a dural tear during spinal surgery have caused pseudomeningocele formation that erodes the vertebral body, resulting in persistent bleeding from the exposed bone marrow into the subarachnoid space. In these cases, the iatrogenic dural defect should be surgically repaired during the initial surgery to prevent ongoing CSF leak and the development of iatrogenic SS. In iatrogenic SS patients with pseudomeningocele, duralplasty is effective in halting or delaying the progression of hemosiderin deposition on the brain surface and spine by mitigating hemorrhage from the bone marrow into the subarachnoid space.