Delayed Retroclival and Cervical Spinal Subdural Hematoma Complicated by Preexisting Chiari Malformation in Adult Trauma Patient

INTRODUCTION: Traumatic spinal subdural hematoma involving the retroclival region and upper cervical spine is a rare pathology. To our knowledge, there have only been 2 prior cases in an adult trauma patient. We describe a patient with preexisting Chiari 1 malformation, who recently sustained a unilateral type 1 occipital condyle fracture with associated disruption of the tectorial membrane and transverse ligament, which returned with a retroclival subdural hematoma extending down to C7, causing spinal cord compression and symptomatic obstructive hydrocephalus. \ CASE PRESENTATION: A 30-year-old female sustained a motor vehicle collision. Computed tomography C spine revealed a type I occipital condyle fracture. Magnetic resonance imaging C spine demonstrated disruption of the tectorial membrane and avulsion of the transverse ligament at its attachment to the left C1 tubercle; moreover, there was a Chiari 1 malformation. The patient was neurologically intact. A halo was recommended, but the patient opted for an aspen collar with close management. She was discharged but returned 3 days later with apneic episodes, along with bradycardia and hypertension. She was promptly intubated. Computed tomography head showed interval ventricular enlargement. Magnetic resonance imaging C spine revealed a new ventral hematoma spanning the retroclival region to C7, most pronounced at C2-C3. On examination, she opened her eyes to pain, her pupils were equal and reactive, and she withdrew in all extremities. An external ventricular drain was emergently placed. She underwent a suboccipital craniectomy, C1-3 laminectomies, and occiput-C4 instrumented fusion. The dura was significantly tense, and no epidural hematoma was observed during lateral exploration. Postoperatively, she woke up well, exhibiting a nonfocal neurologic examination. A diagnostic angiogram was negative. She was extubated uneventfully, and the external ventricular drain was weaned off in 4 days. CONCLUSION: Traumatic spinal subdural hematoma involving both the retroclival region and upper cervical spine can lead to bulbar signs and symptomatic obstructive hydrocephalus. There should be vigilance for this pathology in patients with high-energy craniocervical trauma. Disruption of the tectorial membrane and therapeutic anticoagulation may be risk factors. The clinical scenario can be complicated in the setting of a preexisting Chiari 1 malformation.