Tumor excision surgeries of the spine present a distinct challenge regarding maintenance of spinal cord blood supply because they often require preoperative embolization of segmental arteries, ligation of the nerve roots corresponding to the level of tumor-affected vertebrae, and circumferential exposure of the dural sac.1,2 Possible circulatory compromise after these maneuvers is an important concern, especially in repeated or multilevel tumor excision. The authors present a case of delayed-onset spinal cord infarction after repeated tumor excision surgeries of the thoracic spine.
A 49-year-old man was referred for tumor recurrence of a metastatic bone lesion from renal cell carcinoma. He had undergone a left nephrectomy 16 years ago, 2 pulmonary metastasectomies 9 and 7 years ago, and excision of a left sixth rib metastasis 3 years ago. He had a recurrence of the bone metastasis involving the left fourth and fifth ribs and T5 vertebra (Figure 1). The patient was neurologically stable on admission to the authors' hospital. He underwent preoperative embolization of the left third and fourth intercostal arteries and the right fourth to sixth intercostal arteries, which supplied the tumor. Tumor excision of the left fourth and fifth ribs and spondylectomy of T5 were performed using the single posterior approach. An anterior cage with autogenous bone graft was placed in the vertebral defect, and posterior instrumentation from T3 to T7 was performed.
Magnetic resonance imaging of the thoracic spine at the time of referral to the authors' institution. Sagittal (A) and axial (B) contrast-enhanced magnetic resonance images showing the recurred tumor involving the left fourth and fifth ribs and T5 vertebra. The arrow indicates the recurred tumor of the left fifth rib.
However, 6 months later, additional tumor recurrence involving the left seventh and eight ribs and T7 vertebra was found. The patient underwent a second preoperative embolization of the bilateral seventh and eighth intercostal arteries, tumor excision of the left seventh and eighth ribs, spondylectomy of T7, and posterior instrumentation from T3 to T9.
Eight months after the second surgery at the authors' hospital, the patient had developed Frankel C paraparesis. Magnetic resonance imaging revealed a tumor recurrence in the T6 vertebra, which was located between the spondylectomy levels (Figure 2). The patient underwent a third preoperative embolization of the right sixth intercostal artery, which had redeveloped as a feeder of blood to the tumor. He also underwent circumferential spinal cord decompression by debulking the tumor, which required ligation of the corresponding bilateral nerve roots of T6. The patient's neurological status improved in the immediate postoperative period. However, 30 hours after surgery, he experienced severe back pain and worsened neurological symptoms. Thirty-six hours after surgery, the paraparesis progressed to Frankel B paraplegia. Although magnetic resonance imaging showed that the spinal cord was adequately decompressed, there was a high-signal lesion on the spinal cord on T2-weighted magnetic resonance images (Figure 3). The postoperative paraplegia was diagnosed as delayed-onset spinal cord infarction. The patient received intravenous administration of a steroid, a free radical scavenger, and low-dose heparin. However, neurological function did not improve. Twenty months after the infarction, the patient had no improvement of the paraplegia.
Illustration of the thoracic spine with a tumor recurrence at the T6 vertebra 8 months after the second tumor excision surgery at the authors' hospital (A). Illustration of the location where embolization and nerve root ligation were performed. The red crosses represent the embolization sites, and the 2 parallel red lines represent the nerve root ligation sites (B).
Axial (A) and sagittal (B) T2-weighted magnetic resonance images after the third surgery showing adequate decompression and a high-signal lesion in the spinal cord.
This patient developed delayed-onset paraplegia after repeated spinal tumor excisions that involved the preoperative embolization of 9 intercostal arteries at 6 consecutive levels and ligation of 6 nerve roots at 3 consecutive levels (Figure 2). The authors considered that the paraplegia originated from spinal cord ischemia. Intraoperative neuromonitoring is a common tool used in spine surgery to avoid iatrogenic neurological injury.3 All tumor excision surgeries of the thoracic spine were performed with neuromonitoring using somatosensory evoked potentials/motor evoked potentials. Intraoperative somatosensory evoked potential/motor evoked potential changes or immediate postoperative neurological deficit were not observed in each surgery. However, the authors did not perform the monitoring during the preoperative embolization or the postoperative period. Intraoperative neuromonitoring has limited ability to detect delayed-onset paraplegia.
On the basis of the results of spondylectomy on up to 3 vertebrae, Murakami et al4 reported that interruption of up to 3 pairs of segmental arteries, including pairs at the level of the artery of Adamkiewicz, and/or ligation of the corresponding nerve roots do not adversely affect neurologic function. This may be related to the theory that the blood supply to the spinal cord is protected by 3 arterial plexus layers—epidural, dural, and pial arteries—that may compensate blood supply during the spinal cord ischemia.4 Kato et al,5 using a dog model, showed that interruption of bilateral segmental arteries at 4 or more consecutive levels, including the level of the Adamkiewicz artery, may lead to ischemic spinal cord dysfunction. However, no clinical reports have described in detail the postoperative course of patients with spinal tumors who undergo preoperative embolization of bilateral segmental arteries at 4 or more consecutive levels and/or intraoperative ligation of the corresponding nerve roots. Luzzati et al6 reported that among 4 patients undergoing multilevel total en bloc spondylectomy at 4 or 5 consecutive levels, 1 patient had a major neurologic deterioration postoperatively. However, the etiology of the neurological deficit was unknown because there was no information about the preoperative embolization, surgical procedure, and postoperative course. In the current case, the maneuvers for spinal tumor excisions, which involved embolization of 9 segmental arteries at 6 consecutive levels and ligation of bilateral nerve roots at 3 consecutive levels, led to delayed-onset spinal cord infarction. Hence, it is suggested that embolization of bilateral segmental arteries at 4 or more consecutive levels and/ or ligation of bilateral nerve roots pose a risk for ischemic spinal cord disease in humans. If bilateral segmental arteries at 4 or more consecutive levels and/or ligation of bilateral nerve roots must be sacrificed, preservation of every possible spinal perfusion is needed, and preoperative embolization procedures should not be performed in the second and third surgeries. Although there are clinically useful maneuvers, which include cerebrospinal fluid drainage via lumbar cannulation of the intrathecal space or systemic cooling,7,8 the authors did not perform these in this case.
In studies using dogs that examined spinal cord ischemia by interruption of segmental arteries, spinal cord blood flow gradually decreased after ligation of segmental arteries, and abnormal findings in neuromonitoring were observed several hours after ligations.5,9 In the current case, gradual decrease of spinal cord blood flow postoperatively may have led to delayed-onset spinal cord infarction. In vascular surgeries, delayed-onset paraplegia and paralysis due to spinal cord ischemia after repair of thoracoabdominal aortic aneurysm have been reported.10 The mechanisms of the delayed development of paraparesis and paraplegia remain ill defined. However, like acute neurologic deficits, delayed-onset deficits result from an agglomeration of events leading to spinal cord ischemia and infarction. The gradual onset of tissue edema to a critical level possibly causes a delayed decrease in spinal cord perfusion and manifestation of neurologic deficits.11 Hence, in spine tumor surgery, delayed-onset paraplegia or paraparesis as well as acute-onset paraplegia or paraparesis due to spinal cord ischemia should be considered major operative complications. In particular, in repeated or multilevel tumor excision, which requires embolization of segmental arteries at 4 or more consecutive levels and/or ligation of the corresponding nerve roots, there is a risk of spinal cord ischemia that is capable of injuring the spinal cord.
The authors presented a case of delayed-onset paraplegia due to spinal cord infarction after repeated tumor excision surgeries of the thoracic spine. Preoperative embolization of 9 segmental arteries at 6 consecutive levels and ligation of 6 nerve roots at 3 consecutive levels caused delayed-onset spinal cord ischemia and injury.
- Colman MW, Hornicek FJ, Schwab JH. Spinal cord blood supply and its surgical implications. J Am Acad Orthop Surg. 2015;23(10):581–591. doi:10.5435/JAAOS-D-14-00219 [CrossRef]
- Kawahara N, Tomita K, Murakami H, Demura S. Total en bloc spondylectomy for spinal tumors: surgical technique and related basic background. Orthop Clin North Am. 2009;40(1):47–63. doi:10.1016/j.ocl.2008.09.004 [CrossRef]
- Lakomkin N, Mistry AM, Zuckerman SL, et al. Utility of intraoperative monitoring in the resection of spinal cord tumors: an analysis by tumor location and anatomical region. Spine (Phila Pa 1976). 2018;43(4):287–294.
- Murakami H, Kawahara N, Tomita K, Demura S, Kato S, Yoshioka K. Does interruption of the artery of Adamkiewicz during total en bloc spondylectomy affect neurologic function?Spine (Phila Pa 1976). 2010;35(22):E1187–E1192. doi:10.1097/BRS.0b013e3181e215e5 [CrossRef]
- Kato S, Kawahara N, Tomita K, Murakami H, Demura S, Fujimaki Y. Effects on spinal cord blood flow and neurologic function secondary to interruption of bilateral segmental arteries which supply the artery of Adamkiewicz: an experimental study using a dog model. Spine (Phila Pa 1976). 2008;33(14):1533–1541. doi:10.1097/BRS.0b013e318178e5af [CrossRef]
- Luzzati AD, Shah S, Gagliano F, Perrucchini G, Scotto G, Alloisio M. Multilevel en bloc spondylectomy for tumors of the thoracic and lumbar spine is challenging but rewarding. Clin Orthop Relat Res. 2015;473(3):858–867. doi:10.1007/s11999-014-3578-x [CrossRef]
- Khan SN, Stansby G. Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Cochrane Database Syst Rev. 2012;10:CD003635.
- Cambria RP, Davison JK. Regional hypothermia with epidural cooling for spinal protection during thoracoabdominal aneurysm repair. Semin Vasc Surg. 2000;13(4):315–324.
- Fujimaki Y, Kawahara N, Tomita K, Murakami H, Ueda Y. How many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction? An experimental study using a dog model. Spine (Phila Pa 1976). 2006;31(21):E781–E789. doi:10.1097/01.brs.0000238717.51102.79 [CrossRef]
- Wong DR, Coselli JS, Amerman K, et al. Delayed spinal cord deficits after thoracoabdominal aortic aneurysm repair. Ann Thorac Surg. 2007;83(4):1345–1355. doi:10.1016/j.athoracsur.2006.11.035 [CrossRef]
- Azizzadeh A, Huynh TT, Miller CC, Safi HJ. Reversal of twice-delayed neurologic deficits with cerebrospinal fluid drainage after thoracoabdominal aneurysm repair: a case report and plea for a national database collection. J Vasc Surg. 2000;31(3):592–598. doi:10.1067/mva.2000.102328 [CrossRef]