In the present case, we reported on a patient who developed paraplegia after EVAR. We immediately suspected SCI as the cause; however, postoperative MRI revealed compression of the spinal cord due to a burst fracture of the L1 vertebral body. We determined that static and dynamic compression to the spinal cord was caused by the patient’s supine position and extension of her legs during the operation under general anesthesia. It is important to take account of the possibility of traumatic injury as the cause of postoperative paraplegia, even if it occurs after a minimally invasive procedure such as EVAR. To the best of our knowledge, there have been no reports of paraplegia after EVAR caused by the supine position.
The characteristic adjunct symptom of paraplegia due to SCI after EVAR is superficial but not deep dissociative sensory loss [5,6,7]. The anterior portion of the spinal cord mainly consists of the pyramidal and spinothalamic tracts, which are responsible for motor function, as well as sensations of pain, temperature, crude touch, and firm pressure. On the other hand, the posterior portion of the spinal cord, consisting of the gracile and cuneate fasciculi, is responsible for position sensation, fine touch, vibration sensation, and two-point discrimination. The spinal cord is usually supplied by one anterior and two posterior spinal arteries. Therefore, although EVAR causes substantial hemodynamic changes in the spinal cord, its posterior portion, which is responsible for deep sensation, is less susceptible than its anterior portion to ischemia. Consequently, the characteristic symptom caused by SCI after EVAR is paraplegia, usually without impairment of deep sensation. In contrast, sensory impairment associated with extrinsic spinal cord injury is more varied, depending on the portion that is damaged [1,2,3]. In the current case, we confirmed that the patient experienced not only superficial but also deep sensory impairment; however, her symptoms were atypical of SCI due to EVAR. Therefore, when a patient experiences paraplegia after EVAR, extrinsic factors should also be considered to ensure that the correct treatment is started promptly.
With regard to the patient’s medical history, she was unable to walk unassisted and could not sleep well in the supine position due to severe kyphosis. A patient with spinal stenosis may sustain a spinal cord injury when the spine is extended more than usual. Generally, patients undergoing EVAR need to lie in the supine position and extend both legs for puncturing of the femoral artery. In this case, before performing EVAR, we did not confirm whether the patient was able to extend her legs completely and lie in the supine position for a long time. EVAR is often performed in older individuals; furthermore, the prevalence of symptomatic lumbar spinal stenosis is about 10% in that population . Therefore, before performing EVAR in older individuals, it is important to evaluate their spinal cord and to confirm whether they are comfortable in the supine position.
Additionally, there are some possible improvement points as for treatment. First, in this case, the operation was conducted under general anesthesia with muscle relaxant aiming for hemodynamically stable condition. If we chose local anesthesia with mild sedation, we might have confirmed early, or the force on her back may have weakened. Second, the symptom tended to improve slightly; thus, surgery was not performed at that time, per the patient’s request; however, quick MRI examination and decompression and stabilization of fractured vertebrae might have been desired.
In summary, we reported the case of a 79-year-old woman with paraplegia caused by the compression of the spinal cord after EVAR. As the cause of paraplegia after EVAR, it is important to consider the possibility of extrinsic factors, not only ischemia, in patients with spinal problems. If paraplegia is accompanied by impaired sensation in the lower extremities, physical compression of the spinal nerves may be the cause. In such cases, even with post-EVAR paraplegia, we need to perform an immediate MRI examination to determine the cause of the paraplegia