Contusional Cerebellar Hemorrhage Related to Placement in the Protrusion Position After Atlantoaxial Fusion.

Background: Various complications after C1 lateral mass and C2 pedicle screw fusion surgery (C1LM-C2PSFS) have been reported. However, to our knowledge, this is the first report of contusional cerebellar hemorrhage caused by placement in the protrusion (chin-out) position after C1LM-2PSFS.

Case Description: An 81-year-old woman complaining of gait disturbance and clumsiness of both hands was diagnosed with cervical myelopathy with atlantoaxial subluxation. After we performed C1LM-C2PSFS, her neurologic deficits gradually improved, and there was no radiologic evidence of construct failure. One month after surgery, she had severe headache and vomiting immediately after taking some medications while in the protrusion position. Head computerized tomography scan showed left cerebellar hemorrhage, and titanium rods penetrated the occipital bone on both sides. Flexion/extension radiography showed no loosening of any screws or rods. However, protrusion radiography showed that the tip of the left titanium rod intruded into the intracranial region. We considered that the penetration of the occipital bone by the left titanium rod caused the contusional left cerebellar hemorrhage. We immediately performed revision surgery to replace the titanium rods on each side with shorter rods, and no cerebrospinal fluid leakage was observed. The headache disappeared after the revision surgery.

Conclusions: We report a case of contusional cerebellar hemorrhage caused by the intrusion of a rod into the occipital bone when the patient was placed in the protrusion position. The rod length on the cranial side must be as short as possible, with careful consideration of placing the head in the protrusion position after C1LM-2PSFS surgery.