Unidentified dural tear that results in cerebrospinal fluid (CSF) leakage is a potential complication during spinal operations. The likelihood of this issue increases as the complexity of the procedures increases, especially for revision surgery¹¹⁾. Although most cases of dural injury do not cause intracranial hemorrhage, however, some patients may experience this type of complication.

Intracranial hypotension created by CSF leakage through a durotomy site is considered the main pathogenic mechanism of intracranial hemorrhage^5,13). Various treatment options for both intracranial hemorrhage and durotomy site exist and can be individualized to the patient. The present paper reports a rare case of acute intracranial subdural hemorrhage and intraventricular hemorrhage that resulted from CSF leakage through an unidentified durotomy site during spinal revision surgery combined with preexisting asymptomatic chronic subdural hemorrhage. The intracranial hemorrhages and dural injury site were successfully treated with burr hole drainage alone. Therefore, considerations in the treatment of unidentified durotomy associated with intracranial hemorrhage after spinal surgery are presented.

Incidental durotomy during spinal surgery is a frequent complication for spinal surgeons. The reported prevalence ranges widely from 0.67% to 17.4%^14,15). Immediate diagnosis and primary repair for incidental durotomy at the time of surgery does not affect postoperative clinical outcomes^7), but unidentified durotomy that results in continuous CSF leakage can lead to fatal neurosurgical emergencies. The incidence of durotomy that is clinically significant and not identified at the time of surgery has been reported to be 0.28%³⁾. The majority of these patients report postural headache. Some patients, however, may experience intracranial hemorrhage complications, such as epidural, subdural, intraventricular, and cerebellar hemorrhage with manifested signs of neurological deterioration^6,8,12,16). Secondary intracranial hypotension has been suggested to be a pathogenic mechanism of intracranial hemorrhage^5,13). Iatrogenic CSF leakage causes pressure differences between the intracranial and spinal compartments. The resultant brain sagging toward the skull base stretches and tears the venous structure of the brain and can cause certain types of intracranial hemorrhage, such as subdural or cerebellar hemorrhage.

Zimmerman and Kebaish¹⁶⁾ reported four cases of intracranial hemorrhage after primary repair of incidental durotomy and stated an inability to identify consistent etiologic factors and difficulty in the urgent diagnosis of intracranial hemorrhage because of nonspecific symptoms that are commonly manifested in older patients. Older people constitute the majority of patients who undergo spinal surgery, and their brain condition is more susceptible to the occurrence of intracranial subdural hemorrhage compared with younger patients¹⁾. Our case also presented acute subdural and intraventricular hemorrhage, in addition to the incidental finding of asymptomatic chronic subdural hemorrhage without any history of antiplatelet medication or trauma. Older patients may then be considered more susceptible to the occurrence of intracranial hemorrhage after iatrogenic spinal CSF leakage.

Although rare, the possibly devastating course of this complication suggests that more diagnostic and therapeutic considerations may be needed after the diagnosis of unidentified or delayed dural injury that results in intracranial hemorrhage.

Various treatment options mentioned in previous reports^2,4,9,10) exist, but they must be applied after evaluation of intracranial abnormalities using brain imaging modalities. Primary repair with various sealing materials may be a more reliable method but less effective with regard to its invasiveness and morbidity associated with revision surgery under general anesthesia. Non-operative methods, including bed rest, epidural blood patch, and spinal subarachnoid CSF drainage, may be selected as main or ancillary treatment components. Spinal subarachnoid CSF drainage without information about intracranial hemorrhage⁹⁾ could be more dangerous and may exacerbate the pressure gradient between the intracranial and spinal compartments, leading to enlarge the intracranial hemorrhage.

Cranial subarachnoid CSF drainage has similar mechanism of treatment to its spinal counterpart. However, it has not mentioned in previous articles because of its invasiveness and limitation in general use. Although in particular cases, if the drainage or craniotomy for intracranial hemorrhage resulting from intracranial hypotension is needed, the positioning of a catheter for subsequent cranial CSF drainage could be another treatment option to seal off the spinal dural injury site without secondary intention.

Intracranial hemorrhage resulting from secondary intracranial hypotension associated with unidentified dural injury after spinal surgery is a rare complication. Brain imaging studies to evaluate intracranial abnormalities are essential in the planning of treatment options for the dural injury site. Cranial subarachnoid CSF drainage could be a treatment option for closure of spinal dural tear site in particular case when cranial CSF drainage is possible.