Spinal neurovascular complications with anterior thoracolumbar spine surgery: a systematic review and review of thoracolumbar vascular anatomy.

OBJECTIVE: Spinal cord infarction due to interruption of the spinal vascular supply during anterior thoracolumbar surgery is a rare but devastating complication. Here, the authors sought to summarize the data on this complication in terms of its incidence, risk factors, and operative considerations. They also sought to summarize the relevant spinal vascular anatomy. METHODS: They performed a systematic literature review of the PubMed, Scopus, and Embase databases to identify reports of spinal cord vascular injury related to anterior thoracolumbar spine procedures as well as operative adjuncts and considerations related to management of the segmental artery ligation during such anterior procedures. Titles and abstracts were screened, and studies meeting inclusion criteria were reviewed in full. RESULTS: Of 1200 articles identified on the initial screening, 16 met the inclusion criteria and consisted of 2 prospective cohort studies, 10 retrospective cohort studies, and 4 case reports. Four studies reported on the incidence of spinal cord ischemia with anterior thoracolumbar surgery, which ranged from 0% to 0.75%. Eight studies presented patient-level data for 13 cases of spinal cord ischemia after anterior thoracolumbar spine surgery. Proposed risk factors for vasculogenic spinal injury with anterior thoracolumbar surgery included hyperkyphosis, prior spinal deformity surgery, combined anterior-posterior procedures, left-sided approaches, operating on the concavity side of a scoliotic curve, and intra- or postoperative hypotension. In addition, eight studies analyzed operative considerations to reduce spinal cord ischemic complications in anterior thoracolumbar surgery, including intraoperative neuromonitoring and preoperative spinal angiography. CONCLUSIONS: While spinal cord infarction related to anterior thoracolumbar surgery is rare, it warrants proper consideration in the pre-, intra-, and postoperative periods. The spine surgeon must be aware of the relevant risk factors as well as the pre- and intraoperative adjuncts that can minimize these risks. Most importantly, an understanding of the relevant spinal vascular anatomy is critical to minimizing the risks associated with anterior thoracolumbar spine surgery.

Stroke and spinal infarct caused by percutaneous coronary intervention.

Acute ischaemic stroke is a known risk of percutaneous coronary intervention (PCI). The incidence of such complications has increased in frequency over the last decade due to higher comorbidity burden and increased complexity of PCI procedures. The overall incidence of post-PCI ischaemic stroke remains low at 0.56%, but some groups of patients have significantly higher risk. Risk factors include atherosclerotic plaques, atrial fibrillation, cardiogenic shock, older age and arterial disease. Although the overall incidence of acute ischaemic stroke following PCI is low, it can result in lifelong disability and is associated with high morbidity, mortality and significant costs. Spinal infarctions due to PCI are exceedingly rare. Here, we discuss a 71-year-old woman who presented with a non ST-elevation myocardial infarction and developed both stroke and spinal infarction post PCI due to a thromboembolic event resulting in long-term debility.

Multi-Site Optical Monitoring of Spinal Cord Ischemia during Spine Distraction.

Optimal surgical management of spine trauma will restore blood flow to the ischemic spinal cord. However, spine stabilization may also further exacerbate injury by inducing ischemia. Current electrophysiological technology is not capable of detecting acute changes in spinal cord blood flow or localizing ischemia. Further, alerts are delayed and unreliable. We developed an epidural optical device capable of directly measuring and immediately detecting changes in spinal cord blood flow using diffuse correlation spectroscopy (DCS). Herein we test the hypothesis that our device can continuously monitor blood flow during spine distraction. Additionally, we demonstrate the ability of our device to monitor multiple sites along the spinal cord and axially resolve changes in spinal cord blood flow. DCS-measured blood flow in the spinal cord was monitored at up to three spatial locations (cranial to, at, and caudal to the distraction site) during surgical distraction in a sheep model. Distraction was halted at 50% of baseline blood flow at the distraction site. We were able to monitor blood flow with DCS in multiple regions of the spinal cord simultaneously at ∼1 Hz. The distraction site had a greater decrement in flow than sites cranial to the injury (median -40 vs. -7%,). This pilot study demonstrated high temporal resolution and the capacity to axially resolve changes in spinal cord blood flow at and remote from the site of distraction. These early results suggest that this technology may assist in the surgical management of spine trauma and in corrective surgery of the spine.

Definition of safe zone in vertebral body in relation to anterior instrumentation.

OBJECTIVES: We set out to determine the "safe zone" for anterior instrumentation in scoliosis surgery assessing the relationship of the great vessels to the spine. METHODS: A total of 34 children undergoing posterior idiopathic scoliosis surgery were included in the study between 2010 and 2016. The preoperative scans were assessed to identify the position of the great vessels relative to the spine from T4 to L4. A coordinate system was specifically designed to determine safe zones for device locations. The safe zone right (SZR) was defined as the angle formed between X-axis (0°) and a line connecting the origin and the edge of the aorta and the safe zone left (SZL), the angle between the edge of the aorta to 180°. RESULTS: The average age was 14 years, with 30 females (88.2%). Lenke classification, the most common curve was 1BN (20.6%), followed by 1AN, 3C- and 6CN (8.8% each). The Apex was T8 and T9 (29.4 and 23.5% respectively). 58% of the curves were right sided. The mean SZL was from 155.7° to 180° at the T4 level to 104.3°-180° at L4. The mean SZR was from 0 to 110.7° at T4 to 0-76.18° at L4. The side of the curves was correlated at p level with the SZL and SZR. There was a significant correlation in the following levels: from T4 to L2 in the SZL, and from T7 to L2 in the SZR. CONCLUSIONS: Between T4 and T11, the right side of the vertebrae is safe, and from T12 to L4 the safe zones are more lateral and smaller. In a right-sided scoliosis, the danger zone moves more posterolateral at every level. In a left-sided curve, the danger zone is more anteromedial. Knowledge of these safe zones should allow safer placement of anterior devices. LEVEL OF EVIDENCE: Level III.

Anatomical investigation of the segmental vessels for the right-sided anterior surgical approach to the thoracic spine: a human cadaver study.

PURPOSE: Anterior surgical approaches to the thoracic spine are common procedures for the treatment of many diseases of the thoracic spine. Purpose of this anatomic study is to investigate the course of the segmental vessels of the thoracic spine for the anterior and lateral transthoracic approach from the right side. METHODS: 26 formalin-fixed human cadavers (20 femaless/6 male) with an average age of 84.9 ± 8.3 (range 67-97) were included. The segmental arteries and veins of the right thoracic cavity coursing between the third and twelfth thoracic vertebral body have been investigated. To define the localization of the vessels in accordance with the associated vertebral bodies, the distance between the endplates and vessels was measured in the ventral, middle and dorsal parts. RESULTS: The results of the study reveal that not only one, but also two segmental arteries and veins may course over the right hemi-vertebral body, especially in the upper and middle thoracic spine. Furthermore, in the middle and lower thoracic spine (T7-T12) the vessels course over the middle and lower third of the craniocaudal extent of the vertebral body. On the contrary, in the upper thoracic spine (T3-T6), the vessels may course over the entire extent of the vertebral body. CONCLUSION: Due to these common anatomic variations and variability of the course of the segmental vessels, spinal surgeons should remain careful in the identification of the segmental vessels in order to minimize risk of vascular injury in case of right-sided anterior and lateral approach to the thoracic spine.

The position of the aorta relative to the spine in patients with adult degenerative scoliosis.

STUDY DESIGN: A retrospective analysis was conducted to analyze the position of the aorta by MRI in patients with adult degenerative scoliosis. OBJECTIVE: This study aimed to investigate the relative anatomic positions of the aorta and spine in patients with adult degenerative scoliosis (ADS). Aorta injury is a rare complication of spinal surgeries. However, there would be a disastrous consequence once it happened. Therefore, knowing about the position of aorta is of great importance. METHODS: A retrospective analysis was performed in 90 patients with ADS and 132 participants without spine deformity. ADS patients were divided into several groups such as left scoliosis, left scoliosis with thoracolumbar kyphosis, right scoliosis, and right scoliosis with thoracolumbar kyphosis. The aorta-vertebrae angle (α) and aorta-vertebrae distance (d) in each level of T12-L4 were measured by using a Cartesian coordinate system. t test of independent samples was performed, α and d were compared, and Pearson correlation analysis was employed for α, d, and X-ray radiographic measurements. RESULT: The changes of α were not statistically significant (P > 0.05) in LS and LKS groups but d (P < 0.05) was longer in LKS group compared with the control group. In the right malformed group, there was no significant change in the angle (P > 0.05) in the abdominal aorta but longer d (P < 0.05) than the normal group. There was longer d in the RKS group compared with the RS group (P < 0.05). Pearson correlation analysis showed that there was a positive correlation between d and TLK (r = 0.439, P < 0.05). CONCLUSION: In patients with ADS, a relative normal position is maintained between the aorta and vertebrae. While the aorta is slightly away from the left pedicle in RS patients and farther away in patients with kyphosis, the angle of kyphosis would become bigger and d becomes longer. Therefore, the surgeons should be aware of the changes of the aorta position to avoid the disastrous vessel injuries.

Late Manifestation of Pulmonary Cement Embolism Visualized by Coronary Angiography.

Following percutaneous vertebroplasty for vertebral compression fracture 6 years prior, late pulmonary cement embolism developed after leakage of the cement into the paravertebral venous plexus.

Association between false lumen segmental arteries and spinal cord ischemia in type A acute aortic dissection.

BACKGROUND: Spinal cord ischemia (SCI) and paraplegia are complications of surgery for type A acute aortic dissection (TAAAD). Since the segmental arteries play a key role in SCI, this study evaluated the association between SCI and false lumen segmental arteries (FLSAs: segmental arteries originating from the false lumen). METHODS: The study included 101 consecutive TAAAD patients (mean age, 66±13; range, 34-89 years) who underwent surgery from January 2011 to April 2017. The diagnosis of TAAAD and the number of FSLAs were determined by preoperative computed tomography (CT). Patients were divided into two groups according to the number of FLSAs at the Th9-L2 level: Group A (N.=13), ≥8 FLSAs; and group B (N.=88), ≤7 FLSAs. Preoperative, perioperative, and postoperative findings were compared between the groups, and risk factors for SCI were evaluated. RESULTS: The frequency of preoperative paralysis was significantly higher in Group A than Group B (P=.0070). The overall incidence of postoperative SCI was 8% (8/101) and significantly higher in Group A than Group B (5/13 [45%] vs. 3/88 (4%), P<0.0001). Hospital mortality was 8% (8/101) and significantly higher in Group A than Group B (3/13 [23%] vs. 5/88 [6%], P=.0302). Multivariate analysis showed that the independent risk factors for SCI were ≥8 FLSAs at Th9-L2 (odds ratio [OR], 20.4; 95% confidence interval [95% CI], 3.34-124.9, P=0.0011) and diabetes mellitus (OR, 22.3; 95% CI, 1.69-294.5; P=0.0184). CONCLUSIONS: In patients who underwent surgery for TAAAD, ≥8 FLSAs at the Th9-L2 levels on preoperative CT was a risk factor for SCI.

Nutrient foramen location on the laminae provides a landmark for pedicle screw entry: a cadaveric study.

BACKGROUND: Nutrient foramina are often encountered around the entry point of pedicle screws. Further, while probing the pedicle for pedicle screw insertion around the nutrient foramen, bleeding from the probe insertion hole is often observed. The purpose of this study was to investigate the frequency of occurrence of nutrient foramina, the association between the nutrient foramen and pedicle, and the safety and accuracy of cervical and thoracic pedicle screw placement using the nutrient foramen as the entry point. METHODS: We identified the location of the nutrient foramina for the dorsal branches of the segmental artery and their anatomical association to the pedicles and bony landmarks in the vertebrae for C3-T12 in seven cadavers. We also determined the frequency with which the nutrient foramina were present in 119 cadaveric vertebrae. We identified the pedicle location, base of the superior articular facet, and lateral border of laminae with respect to the nutrient foramen. RESULTS: The overall presence of the nutrient foramina was 63% (150/238) in the specimens, with 60% (42/70) and 64% (108/168) identifiable in the cervical and thoracic vertebrae, respectively. In the cervical vertebrae, the nutrient foramen was located on the outer wall of the pedicle and was positioned between the cephalad and caudal walls. In the thoracic spine, 98% (106/108) nutrient foramina were located inside the pedicle walls. CONCLUSIONS: Our study findings confirm that the location of the nutrient foramen can be used for identifying the entry point for pedicle screws. In the cervical vertebrae, the nutrient foramina are located lateral to pedicle but within the cranial and caudal margins. In the thoracic vertebrae, the nutrient foramina are located in the medial and caudal regions of the pedicle. Thus, to decrease the risk of overshoot, the entry point for thoracic pedicle screws should be positioned a few millimeters cephalad and lateral to the nutrient foramen.

Additive Value of 3T 3D CISS Imaging to Conventional MRI for Assessing the Abnormal Vessels of Spinal Dural Arteriovenous Fistulae.

INTRODUCTION: We investigated the additive value of the 3T 3D constructive interference in steady state (CISS) sequence to conventional MRI for the evaluation of spinal dural arteriovenous fistulae (SDAVF). MATERIALS AND METHODS: We included 16 consecutive patients (15 men, 1 woman; age range 42-81 years; mean 64 years) with SDAVF who underwent 3T MRI and digital subtraction angiography (DSA) before treatment. Two neuroradiologists independently evaluated the presence of abnormal vessels on 3D CISS-, T2- and T1-weighted images (T1WI, T2WI), and contrast-enhanced T1WI using a 3-point grading system. Interobserver agreement was assessed by calculating the κ coefficient. RESULTS: The SDAVF site was the cervical region in one patient, the thoracic region in 12 patients, the lumbar region in two, and the sacral region in one. For the visualization of abnormal vessels, the mean score was significantly higher for 3D CISS than the other sequences (P < 0.05). In 12 of 16 cases (75%) both readers made definite positive findings on additional 3D-CISS images. Interobserver agreement was excellent for 3D CISS images (κ = 1.0), good for T1WI (κ = 0.78; 95% confidence interval [CI] 0.54-1.00) and T2WI (κ = 0.74; 95% CI 0.48-1.00) and moderate for contrast-enhanced T1WI (CET1WI) (κ = 0.50; 95% CI 0.21-0.80). CONCLUSION: For the assessment of abnormal vessels of SDAVF, the 3T 3D CISS sequence adds value to conventional MRI.

Influence of blood supply on fracture healing of vertebral bodies.

INTRODUCTION: The relevance of blood supply for bone fracture healing has been discussed throughout the literature, using scaphoids as the most referred to. But, there is virtually nothing known about the relevance of blood supply for the vertebral fracture healing and even the guidelines of AO do not deal with this issue. MATERIALS AND METHODS: A prospective cohort study of 107 patients was run from January 2016 to December 2016, with 54 male and 53 female patients, who were treated for traumatic vertebral fractures of thoracolumbar spine using posterior stabilization only. The average age was 67 years and the follow-up 12.3 weeks. The total number of vertebrae was 129. We analyzed the fracture morphology and measured the vertebral bodies in all three dimensions, with five reference planes. The progress of vertebral deformity in time measured before and after the surgery was correlated with the potential damage of the main vascular canal in the rear of each vertebral body. The bone pattern and morphology were analyzed in detail as well. Pathological fractures were not taken into our consideration. RESULTS: The overall deformity progression of vertebral bodies in the fractures with morphologically damaged blood supply was in all measured dimensions significantly higher than in the fractures with supposedly maintained perfusion. The osteoporosis played its role as well, but only with medium effect size compared with strong effect size of the vessel canal damage (Cohen). The combination of the both factors (damage to the vessel canal together with osteoporosis) showed also a strong correlation with a relevant deformity progression (Evans), but not much different from the vessel canal damage alone. With regard to the relevant changes of the vertebral body dimensions/volume, we found relevant changes in 52% of all fractures (SD 0.5017) generally, for the subgroup with the canal damage in 84% (SD 0.3691), with strong correlation (Evans, 0.7721). In the group of fractures with maintained perfusion, we found such changes in only in 5% of fractures (SD 0.2333). CONCLUSION: For decision making, we should take mechanical fracture analysis and dynamic processes within traumatized tissue a part of whose is the blood supply and oxygenation into surgical consideration. We recommend anterior rather than posterior stabilization for the cases with damaged vessel canal, and the vertebroplasty could pose an alternative in the elderly.

A comparison of vertebral venous networks in adolescent idiopathic scoliosis patients and healthy controls.

PURPOSE: Cadaveric studies have previously documented a typical pattern of venous drainage within vertebral bodies (VBs), comprised primarily of the basivertebral vein. These studies, however, are limited by the number of samples available. MRI is able to provide 3D images of soft tissue structures in the spine, including the basivertebral vein without the use of contrast in both healthy controls and subjects with abnormal anatomy such as adolescent idiopathic scoliosis (AIS). This study aimed to quantify the venous networks within VBs of 15 healthy adolescent controls and 15 AIS patients. METHODS: Five transverse slices through the VBs were examined simultaneously and the observable vascular network traced. The length of the network on the left and right sides of the VB was calculated, and the spatial patterning assessed level-by-level within each subject. RESULTS: Significant differences were seen in the left/right distribution of vessels in both the control and AIS subjects, with both groups having greater length on the right side of all of their VBs. No difference was seen between AIS and control subjects in any region. Large individual variations in patterns were seen in both groups; however, the control group showed more consistent spatial patterning of the vascular networks across levels in comparison to the AIS group. CONCLUSION: The length of the basivertebral vein was seen to have a significant bias to the right hand side of the VB in both healthy and AIS adolescents. The spatial pattern of this vein showed large variations in branching both within and across individuals. No significant differences were seen between AIS and control subjects, suggesting both that this network is preserved in deformed AIS vertebrae, and that the vertebral venous system does not play a role in the etiology of AIS.

Microanatomy of the brachial plexus roots and its clinical significance.

PURPOSE: To provide the anatomical basis of brachial plexus roots for the diagnosis and treatment of brachial plexus root avulsion injury. METHODS: The morphological features of brachial plexus roots were observed and measured on 15 cervicothoracic spine of adult cadavers. The relationship of brachial plexus nerve roots and the surrounding tissues also were observed, as well as the blood supply of anterior and posterior roots of the brachial plexus. RESULTS: Origination of the nerve roots in the dorsal-ventral direction from the midline was fine-tuned at each level along the spinal cord. The minimum distance of the origin of the nerve root to midline was 2.2 mm at C 5, while the maximum was 3.1 mm at T 1. Inversely, the distance between the origin of the posterior root and the midline of the spinal cord gradually decreased, the maximum being 4.2 mm at C 5 and minimum 2.7 mm at T 1. Meanwhile, there was complicated fibrous connection among posterior roots of the brachial plexus. The C 5-6 nerve roots interlaced with tendons of the scalenus anterior and scalenus medius and fused with the transverse-radicular ligaments in the intervertebral foramina. However, these ligaments were not seen in C 7-8, and T 1. The blood supply of the anterior and posterior roots of the brachial plexus was from the segmental branches of the vertebral artery, deep cervical artery and ascending cervical artery, with a mean outer diameter of 0.61 mm. CONCLUSIONS: The systematic and comprehensive anatomic data of the brachial plexus roots provides the anatomical basis to diagnose and treat the brachial plexus root avulsion injury.

Delayed onset paraparesis complicating epidural steroid injection with underlying spinal dural arteriovenous fistula.

We report a case of a 48-year-old man with chronic back pain attributed to discogenic lumbar radiculopathy who underwent a fluoroscopy-guided L2-3 interlaminar epidural steroid injection. 4 h later, he developed acute paraparesis, sensory loss below T10 level and urinary retention. MRI of the thoracic spine revealed diffuse abnormal T2/FLAIR signal and extensive vascular flow voids. A spinal dural arteriovenous fistula was confirmed on spinal angiography. Embolization of the spinal dural arteriovenous fistula resulted in significant improvement of symptoms. We review previously reported cases and current understanding of the pathophysiology of this complication. All cases had symptom onset several hours after the procedure. There seems to be a trend toward better outcomes with earlier treatment.

Retrospective analysis of intravertebral collateral enhancement in patients with central venous obstruction.

OBJECTIVE: To compare prevalence and patterns of intravertebral collateral enhancement in patients with and without central venous obstruction (CVO). MATERIALS AND METHODS: Chest CTs performed between 1/1/2000 and 12/15/2012 with reports containing terms indicating CVO were identified. All contrast enhanced CTs were examined for the presence of CVO and collateral venous pathways. If intravertebral collateral enhancement was present, the pattern was recorded as nodular, linear, or both. RESULTS: In 209 suspected cases of CVO, 53 (25 %) were confirmed with obstruction and 156 (75 %) were without obstruction. In patients with CVO, 47 % (25/53) demonstrated collateral venous flow through an intravertebral marrow pathway compared to 5 % (8/156) of patients without CVO (P < 0.0001). The most common level of enhancement was the upper thoracic spine, involving only the vertebral body. Nodular, linear, and combined nodular-linear enhancement patterns were seen with similar frequency. Nodular intravertebral collateral enhancement was mistaken for sclerotic metastases in 33 % (3/9) of cases. CONCLUSION: Intravertebral collateral enhancement was seen in almost half the patients with CVO and when nodular enhancement is present, it is important to differentiate between metastatic lesions and enhancement related to CVO.

Intradural spinal arteriovenous malformation in a 13-month-old female: A case report.

PURPOSE: Describe the case of a spinal arteriovenous malformation (AVM), which represents a rare cause for tetraplegia in the infant population. TREATMENT: This patient underwent treatment with surgical clipping of an intradural AVM, intravenous steroids, and inpatient rehabilitation. DISCUSSION: Although AVMs are a congenital vascular malformation, spinal AVMs are extremely rare with only a few case reports published in the pediatric literature. Generally AVMs are diagnosed intracranially which would lead to cerebral infarction; however, in this case, the AVM was in the cervical spinal cord leading to tetraplegia. With medical and rehabilitation interventions, the patient's function improved significantly; however, long-term prognostication remained difficult given the lack of standardized assessments and the inaccuracy of the American Spinal Injury Association (ASIA) examination for this age group. CONCLUSION: Spinal AVMs are extremely rare in the pediatric population; however, with this case the use of surgical intervention helped prevent further loss of neurologic impairment, and inpatient rehabilitation served to increase the patient's function. She continued to participate in outpatient rehabilitation to improve developmental milestones, mobility, posture, positioning, and upper limb function.