Bladder and rectal incontinence without paraplegia or paraparesis after endovascular aneurysm repair

Discussion

SCI has been reported after endovascular aneurysm repair (EVAR) either as an immediate or a delayed finding [4]. An analysis of the EUROSTAR database including 2862 patients who have undergone EVAR found an incidence of SCI of 0.21 % [5]. Peppelenbosch et al., however, reported that SCI occurred in 4 out of 35 (11.5 %) patients with a ruptured AAA after the deployment of an AUI device [6]. Bajwa et al. also reported bilateral lower extremity motor and sensory loss with no bladder dysfunction after the deployment of an AUI device [7]. No reports, however, have been published about isolated bladder and rectal incontinence after EVAR.

The process leading to SCI after elective surgical management of an infrarenal AAA has not been fully understood. Factors that may contribute to it after EVAR include atheromatous embolization, interruption of the great radicular artery (artery of Adamkiewicz), or collateral circulation (internal iliac arteries-lumbar arteries) [1, 4, 7]. In our case, because lumbar arteries were “sacrificed” after the EVAR, there is a possibility that flow to the great radicular artery and the collateral circulation might have been interrupted causing this patient’s SCI.

Atheroembolization is a well-known complication of endovascular surgery and may lead to SCI. Rockman et al. reported two cases of paraplegia as a result of atheroembolization to the spinal cord after successful or attempted endovascular management of AAA [4]. In the EUROSTAR registry, factors associated with intraoperative microembolization included long procedure time (>150 min), extensive intravascular handling, and preoperative or perioperative embolization of the hypogastric and lumbar arteries [5]. In our case, the ilio-femoral artery bypass improved iliac artery flow, but SCI still occurred. Also, this patient did not have other signs of atheroembolization such as livedo reticularis or acute renal failure. The development of urinary and fecal incontinence in our patient might have been secondary to the interruption of the great radicular artery, atheroembolization, prolonged operation time, and bleeding. Balloon dilatations, deployment of the proximal converter, and distal iliac extension may have increased the risk of atheroembolization. The improvement of endovascular devices by reduction in their profile (size and length) in combination with improvement in the surgeon’s manipulation technique can be beneficial and may eventually lead to a reduction in the risk of atheroembolization in the future.

The patient’s clinical presentation is explained by the anatomy of the conus medullaris. The conus medullaris is the lower end of the spinal cord, and it usually occurs at the level of the first lumbar vertebra. The segments of spinal cord that give origin to the nerves that control the bladder and bowel sphincters are located below the third sacral segment (S3). An injury to the conus medullaris below the third sacral segment (S3) will manifest with bladder and rectal incontinence and symmetric sensory loss around the anus and sexual organs. Motor dysfunction will not develop because most of the lower extremity motor nerves originate above the S2 segment of the spinal cord [8]. Although it was unrelated to an EVAR procedure, Inatomi et al. [9] previously reported three patients with spinal cord ischemia whose symptoms started with urinary dysfunction without paraplegia or paraparesis. In our case, the clinical manifestations and imaging finding supported the diagnosis of bladder and rectal incontinence due to a spinal cord injury at the level of the conus medullaris.

The goal of the treatment for SCI is to augment spinal cord perfusion pressure and reduce edema. The usefulness of the COPS protocol (CSF drainage to maintain a pressure of less than 5 mmHg without limit under CSF drain status/oxygen delivery/patient status) has been reported after delayed neurologic deficit in thoracoabdominal aortic aneurysm repair [10]. Other therapeutic strategies include CSF drainage, steroids, arterial pressure augmentation, hypothermia, and HBO treatment. We did not perform CSF drainage since it carries a risk for further complications, and its benefit for delayed bladder and rectal incontinence is unproven.

HBO therapy has sporadically demonstrated a decrease in the size of infarcts [11]. In the above case, HBO therapy was selected because of its non-invasive nature; however, other strategies, such as CSF drainage and steroids, may be more beneficial in selected cases. Although there are no guidelines on the number and length of time of HBO treatment, the above patient underwent the standard method of two times the atmospheric pressure for 90 min.