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Competing Interests: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.

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.

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.

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.

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.

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., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

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.

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.

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.

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.

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-, T 2 - and T 1 -weighted images (T 1 WI, T 2 WI), and contrast-enhanced T 1 WI 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 T 1 WI (κ = 0.78; 95% confidence interval [CI] 0.54-1.00) and T 2 WI (κ = 0.74; 95% CI 0.48-1.00) and moderate for contrast-enhanced T 1 WI (CET 1 WI) (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.

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.

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.

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.

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.

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.

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.

The aim of this study was to investigate the arterial blood supply of the thoracolumbar spinal cord in rabbit. The study was carried out on twenty adult New Zealand white rabbits. Ten rabbits were used in the corrosion technique and ten rabbits in the dissection technique. After the killing, the vascular network was perfused with saline. Batson's corrosion casting kit no. 17 © was used as a casting medium. After polymerisation of the medium, in ten rabbits the maceration was carried out in KOH solution, and in ten other rabbits, formaldehyde was injected by the dissection technique into the vertebral canal. We found high variability of segmental arteries supplying blood to the spinal cord. There are 12 intercostal arteries and 1 costo-abdominal artery. Dorsal branches arising from the dorsal surface of the aorta thoracica were found as follows: in 70% of the cases, 9 pairs were present; in 20% of the cases 8 pairs; and in 10% of the cases 10 pairs. The paired arteriae lumbales were present in 6 pairs in 90% of the cases and in 5 pairs in 10% of the cases. On the dorsal surface of spinal cord, we found two irregular longitudinal arteries in 70% of the cases, no longitudinal arteries in 20% of the cases and three irregular longitudinal arteries in 10% of the cases receiving dorsal branches of rami spinales. Among the dorsal branches observed in the thoracic region, 60.5% were left-sided, 39.5% right-sided and in the lumbar region, 52.5% were left-sided and 47.5% right-sided., (© 2013 Blackwell Verlag GmbH.)

Spontaneous spinal epidural hematoma (SSEH) is a rare but real neurosurgical emergency. It is caused by atraumatic rupture of the vertebral epidural vein that results in nerve root or spinal cord compression. Most cases of SSEH have a multifactorial etiology, including congenital and acquired coagulopathies; platelet dysfunction; vascular malformation; tumors; uncontrolled hypertension; pregnancy; and, very rarely, activities requiring Valsalva. Herein we reported the case of a young pianist who was attacked by SSEH during piano practice. Playing the piano is a joyful, relaxing entertainment; however, this musical activity can be a highly demanding physical and mental exercise for pianists. Emotional and expressive performance, especially in professional performing, has been reported to result in significant increase of sympathetic and decrease of parasympathetic activities and thus influence the cardiorespiratory variables. The increased biomechanical stress from fluctuating hemodynamics was thought to trigger the rupture of her spinal arteriovenous malformation.

Background: Transforaminal epidural steroid injection (TFESI) is a widely utilized interventional pain technique for radicular pain. Although the six o'clock position of the pedicle in the so-called "safe triangle" has been used as a target location, there have been a number of reported catastrophic complications of this procedure, including paraplegia. The mechanism of this has been attributed to the intravascular injection of steroids. The goal of this study was to examine the intraforaminal location of thoracolumbar medullary arteries which would help guide pain physicians in developing safer techniques and guidelines., Methods: Twenty-four (24) embalmed cadavers were dissected and examined for the presence and distribution of thoracolumbar anterior medullary arteries. Access to the anterior surface of the spinal cord was made via anterior corpectomy from C2 to S5. Each medullary artery's course was determined by dissection from its origin, the anterior spinal artery, through the intervertebral foramen. The foramen was subsequently opened in the coronal plane, and the intraforaminal location of the artery, its diameter, and its relation to other foraminal structures were examined and measured., Results: In the thoracolumbar foramina (T4-L2), 39 anterior medullary arteries were found, including 23 great medullary arteries (Adamkiewicz artery). One Adamkiewicz artery was found to be located in the left S2 foramen and was not included in the statistical analysis. Of the analyzed 39 anterior medullary arteries, 29 (74%) were located in the upper 1/3 of the foramen, 9 (23%) were located in the middle, and 1 (3%) artery was located in the lower 1/3. In relation to the dorsal root ganglion--ventral root complex, 21 (54%) arteries were located anterosuperiorly, 16 (41%) anteriorly, and 2 (5%) anteroinferiorly. The average intraforaminal artery diameter was 1.20 mm (0.84-1.91 mm). At thoracolumbar levels, the artery is almost always (92% ± 15%) located anterosuperior to the nerve. At typical thoracic levels, it is less often anterosuperior (38% ± 19%), but more often anterior to the nerve., Conclusions: At thoracolumbar levels, if needles were to encounter an artery, they are most likely to do so if placed anterosuperior to the nerve. Encountering an artery anterosuperior to the nerve is less likely at typical thoracic levels, but the likelihood is far from negligible. Pain physicians should be cognizant of this when considering optimal needle placement during transforaminal epidural steroid injections., (Wiley Periodicals, Inc.)

Presurgical devascularization of hypervascular spinal metastases has been shown to be effective in preventing major blood loss during open surgery. Most often, embolization can be performed using polyvinyl alcohol (PVA) microparticles. However, in some cases, the close relationship between the feeders of the metastases and the feeders of the anterior spinal artery (ASA) poses a risk of spinal cord ischemia when PVA microparticle embolization is performed. The authors present their early experience in the treatment of spinal metastases close to the ASA; in 2 cases they injected Onyx-18, by direct puncture, into hypervascular posterior arch spinal metastases situated close to the ASA. Two women, one 36 and the other 55 years of age, who presented with spinal lesions (at the posterior arch of C-4 and T-6, respectively) from thyroid and a kidney tumors, were sent to the authors' department to undergo presurgical embolization. After having performed a complete spinal digital subtraction angiography study, a regular angiography catheter was positioned at the ostium of the artery that mainly supplied the lesion. Then, with the patient in the left lateral decubitus position, direct puncture with 18-gauge needles of the lesion was performed using roadmap guidance. Onyx-18 was injected through the needles under biplanar fluoroscopy. Satisfactory devascularization of the lesions was obtained; the ASA remained patent in both cases. The metastases were surgically removed in both cases within the 48 hours after the embolization and major blood loss did not occur. Presurgical devascularization of hypervascular spinal metastases close the ASA by direct puncture with Onyx-18 seems to be an effective technique and appears to be safe in terms of the preserving the ASA's patency.

The presence of foramina in the transverse processes of thoracic vertebrae is not a common feature while they are the characteristic feature of cervical vertebrae. Foramina present in the transverse process of cervical vertebrae give passage to the vertebral artery-an important artery supplying the brain and spinal cord. Thoracic vertebrae typically bear facets on the body and the transverse processes for articulation with ribs. We report the presence of a complete foramen in the left transverse process of first thoracic vertebra, which is a very rare finding. The foramen was present near the root of the transverse process in alignment with the foramina transversaria of the cervical vertebrae of the same side. This variation is explained embryologically in relation to the branches of dorsal aortae in post-branchial stage of development. Knowledge of such a variation may be of great relevance for accurate interpretation of radiological pictures and for CT and MR angiographies as well as for the management of surgical procedures.

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal arteriovenous malformations. Type 1 spinal arteriovenous malformations are defined by the presence of radiculomeningeal feeders that drain into intradural veins. Patients with these lesions frequently present with chronic myelopathy, which is most often caused by venous hypertension. The authors present the case of a 69-year-old man with acute paraparesis following a lumbar epidural injection, resulting from a previously undiagnosed SDAVF. The patient initially reported right lower-extremity weakness and paresthesias and was referred to an orthopedic practice. His pain and weakness were exacerbated with ambulation. Reevaluation at 4 months was remarkable for groin, mild low-back, and buttock pain. The patient received a right L5-S1 interlaminar epidural steroid injection and became acutely weak. He presented to the emergency department 3 hours after the injection. Once MRI of the lumbar and thoracic spine had been performed, the neurosurgery service was consulted, and it was decided to proceed with emergent spinal angiography with the intent to embolize the fistula. An emergent spinal angiogram was obtained, revealing 2 arterial pedicles emanating from the right T-5 and T-6 radicular arteries. Transarterial embolization was thought to be the most rapid way to potentially obliterate the fistula. The patient exhibited immediate improvement in neurological function, and by 6 hours postprocedure, his neurological function was near normal. He was ambulatory and released to home 3 days after the embolization procedure.

The internal and external vertebral venous plexuses (VVP) extend the length of the vertebral column. Authoritative sources state that these veins are devoid of valves, permitting bidirectional blood flow and facilitating the hematogenous spread of malignant tumors that have venous connections with these plexuses. The aim of this investigation was to identify morphologic features that might influence blood flow in the VVP. The VVP of 12 adult cadavers (seven female, mean age 79.5 years) were examined by macro- and micro-dissection and representative veins removed for histology and immunohistochemistry (smooth muscle antibody staining). A total of 26, mostly bicuspid, valves were identified in 19 of 56 veins (34%) from the external VVP, all orientated to promote blood flow towards the internal VVP. The internal VVP was characterized by four main longitudinal channels with transverse interconnections; the maximum caliber of the longitudinal anterior internal VVP veins was significantly greater than their posterior counterparts (P < 0.001). The luminal architecture of the internal VVP veins was striking, consisting of numerous bridging trabeculae (cords, thin membranes and thick bridges) predominantly within the longitudinal venous channels. Trabeculae were composed of collagen and smooth muscle and also contained numerous small arteries and nerve fibers. A similar internal venous trabecular meshwork is known to exist within the dural venous sinuses of the skull. It may serve to prevent venous overdistension or collapse, to regulate the direction and velocity of venous blood flow, or is possibly involved in thermoregulation or other homeostatic processes., (© 2011 Wiley Periodicals, Inc.)

Cutaneomeningospinal angiomatosis, or Cobb syndrome, is a rare metameric developmental disorder presenting as an extradural-intradural vascular malformation that involves bone, muscle, skin, spinal cord, and nerve roots. A 14-year-old girl with a red nevus involving the T6-9 dermatomes on the left side of her back presented with a 5-year history of bowel and bladder incontinence, paraplegia, and lower-extremity sensory loss. Magnetic resonance imaging demonstrated a hemangioma in the T-8 and T-9 vertebral bodies and a spinal cord AVM nidus extending from T-6 to T-9. The AVM was successfully embolized and the patient regained lower-extremity strength, ambulation, and normal sphincter functions after 5 years of having been wheelchair bound. The authors report the restoration of ambulation after endovascular embolization of a large spinal AVM in a patient with long-standing paraplegia due to Cobb syndrome.

The authors report the case of a patient with an intraosseous spinal arteriovenous malformation (AVM) presenting as an epidural mass lesion that was causing spinal cord compression. The 59-year-old woman had bilateral numbness, weakness, and hyperreflexia of both legs. Magnetic resonance imaging revealed intermediate T1 signal and hyperintense T2 signal involving the right transverse process, bilateral pedicles, and T-5 spinous process; the lesion's epidural extension was causing severe canal compromise and cord displacement. Coil embolization was performed, and the patient underwent resection, after which preoperative symptoms improved. Histopathological analysis revealed a benign vascular proliferation consistent with an intraosseous spinal AVM. On review of the literature, the authors found this case to be the second intraosseous spinal AVM, and the first in a patient whose clinical presentation was consistent with that of a mass lesion of the bone.

A 10-cm diameter tumour was revealed in the left upper posterior mediastinum in a 15-year-old female. After exclusion of the possibility of a dumbbell tumour and confirmation of a ganglioneurinoma, an encapsulated, but vascularised tumour was removed via a left posterolateral thoracotomy from the level of the first-third costo-vertebral angle, without intraoperative complications. Following surgery, acute paraplegia was diagnosed, with a spinal cord lesion at the high thoracic level. Magnetic resonance imaging did not reveal any disorder in the spinal cord. In response to medical treatment, the patient's locomotor and sensation functions normalised within six months. On revising the preoperative computed tomography, we found dilated vessels passing through the tumour and the hypoplastic vertebral artery on the left side. This finding led us to suspect that the spinal cord circulation was partially supplied by the arteries passing through the tumour, which were clipped during surgery. Verification of the blood supply of the spinal cord is therefore highly recommended before resection of a giant tumour from the posterior mediastinum.

Background: Extensive spinal neoplasms are difficult to manage. Following resection, arthrodesis of the spine can be performed with instrumentation, but this often fails in the setting of radiation therapy. Use of the free fibula flap for anterior spinal fusion to correct deformities has been described in multiple studies, but its use for posterior spinal fusion has been limited. In addition, its use in the pediatric population for this purpose has not been reported., Methods: A retrospective review was performed of three pediatric cases of cervical and thoracic spine tumor resection with posterior fusion of the spine with a microvascular fibula flap over a 2-year period. Data recorded included patient demographics, medical/surgical history, indications for surgery, length of free fibula flap, recipient vessels, ischemic time, number of osteotomies performed on the fibula, complications, and time to computed tomography-documented fusion of the fibula to the remaining spinal column., Results: All three microvascular anastomoses were successfully performed using an arteriovenous loop of saphenous vein graft to the anterior neck or subscapular vessels. The average length of fibula harvested was 23.7 cm, the average length of ischemic time was 220 minutes, the number of osteotomies in all cases was two, and there was bony fusion at an average of 15.7 weeks postoperatively., Conclusions: The free fibula flap is ideally suited for accelerated posterior spinal fusion after extensive resection of cervical or thoracic spinal neoplasms. An arteriovenous saphenous vein loop facilitates the microvascular anastomosis in this anatomical region that lacks suitable recipient vessels.

Background and Objectives: Our previous studies in pigs indicate that direct connections exist between the spinal epidural space and the venous circulation. We wondered if similar connections occur in humans and have extended our investigations to human cadavers awaiting autopsy., Methods: We studied 10 recently dead human bodies. We inserted 2 Tuohy needles into the epidural space of the lower thoracic spine at adjacent interspaces. We infused saline with a constant-flow pump into 1 needle and measured the resulting pressure through the other. Epidural pressure increased to a steady plateau during fluid infusion, and this value was recorded at several flow rates. The pressure decay after flow stopped was also recorded. Then we infused radiopaque contrast, removed the needles, and obtained a computed tomographic scan of the spine from the foramen magnum to the coccyx., Results: Pressure in the epidural space increased to a plateau during saline infusion. Higher flow rates produced higher plateau pressures. Plots of plateau pressure versus infusion rate were linear in all bodies. The slope of the flow-pressure plot gave a steady-state resistance (543±638 mm Hg·s/mL). The time constant of the pressure decay curve allowed calculation of initial capacitance (0.090±0.062 mL/mm Hg). Contrast could be identified in veins around the spinal column in all bodies. Contrast was found most commonly in the deep veins of the neck (7 bodies) and in veins originating in the area of the brachial plexus (7 bodies). Contrast was found less commonly and in smaller amounts in veins draining into the azygous system (5 bodies) and the lumbar veins (5 bodies). No contrast was found in veins in the sacral area., Conclusions: A direct connection between the spinal epidural space and the venous circulation has been demonstrated in human cadavers. The connection is most commonly found in the cervical and upper thoracic spine., (Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine)

Purpose: This study introduced an anatomical basis for thoracoscope-assisted thoracolumbar spinal anterior approach., Methods: This work was carried out in terms of 29 corpse specimens anatomizing and the CT three-dimensional images of 25 normal adults observing., Results: The observation by the thoracolumbar spine side of the adult corpse specimens showed that the segmental arteries and veins constantly existed and ran in the central supersulcus of the corresponding vertebral body's side; the segmental artery had several branches; the zone between the upper and lower segmental arteries formed a relative non-vascular nerve safe zone, where the intervertebral space(disc) located. And the observation of the three-dimensional CT image indicated that the segmental arteries were visible and ran in the central supersulcus of the corresponding vertebral body's side, while the branches were invisible. Besides, the arrangement and distribution of the segmental arteries on the three-dimensional CT images and the result were basically consistent with that on corpse specimens., Conclusions: The safe zone, with the intervertebral disc as the reference mark, could provide enough operation space for surgeries such as thoracoscope-assisted anterior interbody fusion and reduce damage to blood vessels as well as surgical complications.

We report a case of direct spinal intradural ventral arteriovenous fistula of the thoraco-lumbar region. Angiography demonstrated a single feeder from the anterior spinal artery that drained directly into a markedly dilated vein without an intervening nidus. The endovascular treatment was performed by a transarterial approach and the occlusion of the fistula, after a failed treatment by a detachable balloon, was obtained by coils released in the initial fistulous site inside a venous dilatation with complete clinical cure. This case indicates that endovascular treatment is possible using coils as a valid and safe alternative to a balloon, glue or surgical approach.

Intercostal arteriovenous malformations (AVM) are rare, with most being secondary to trauma or iatrogenic therapeutic procedures. Only one case of presumably congenital AVM has been reported. Here we report the first case of a ruptured aneurysm of intercostal AVM associated with neurofibromatosis type 1 in a 32-year-old woman who experienced hypovolemic shock caused by massive hemothorax.

A 60-year-old female presented with sudden onset of severe headache and back pain, followed by nausea. The initial head computed tomography (CT) scan revealed posterior fossa subarachnoid hemorrhage (SAH). Spinal T(2)-weighted magnetic resonance imaging demonstrated SAH, and a homogeneous and slightly low signal intensity mass at T11. Spinal angiography in the early arterial phase revealed a small pearl and string-like aneurysm of the proximal radiculomedullary artery on the left side at the T12 level. Forty days after the onset of SAH, CT angiography demonstrated complete occlusion of the dissecting aneurysm and the preserved anterior spinal artery. The present case of ruptured dissecting aneurysm of the radiculomedullary branch of the artery of Adamkiewicz with SAH underwent subsequent spontaneous occlusion, indicating that the wait-and-see strategy may be justified and will provide adequate treatment.

Purpose: The aim of this study was to describe the preoperative topography of the Adamkiewicz artery and the blood supply of the lumbosacral spinal cord in patients who underwent spinal surgery. The relevance for anterior approaches of the thoracolumbar spine was then analyzed., Methods: One hundred consecutive spinal angiographies were reviewed. Surgical indications were: 26 vertebrectomies, 30 anterior fusions in fractures, 13 malunions, 16 anterior releases in scoliosis, 11 pedicle subtraction osteotomies and 4 thoracic disc hernias. The level and the side of the Adamkiewicz artery and the presence of additional radiculomedullary arteries were determined. Modifications of surgical planning owing to the Adamkiewicz artery were analyzed., Results: The Adamkiewicz artery was always located between T8 and L3, at T9 or T10 in 50%, and coming from the left side in 75% of the cases. Additional radiculomedullary arteries were found in 43% of the cases. A concordance between the topography of the Adamkiewicz artery and the planned surgical approach was noted in 15%, which led to ten side changings and three modifications of surgical technique with segmental vessel preservation. An ischemic syndrome of the anterior spinal cord did not occur., Conclusions: Spinal cord ischemia is rarely reported after segmental vessel ligation. Spinal angiography allows determining the topography of the Adamkiewicz artery safely. If the planned surgical approach is located at the same level, a contralateral approach or selective surgical techniques without vessel ligation could avoid possible damage to the Adamkiewicz artery if the pathology does not dictate the side and the extent of the surgical approach.

Purpose: The purpose of this study was to better characterize the intraforaminal location of the great anterior radiculomedullary artery (artery of Adamkiewicz [AKA]) within the neural foramen that would allow safer targeting of thoracic and lumbar transforaminal epidural steroid injections., Material and Methods: A retrospective review of conventional thoracic and lumbar spinal angiograms performed at the Mayo Clinic from 1998-2008 was conducted. Two hundred forty-eight patients were identified and their spinal angiograms reviewed. The cephalo-caudal location of the AKA within the foramen at the mid-pedicular plane was documented along with the side and level of the AKA., Results: From the 248 patients, 113 radiculomedullary arteries could be clearly evaluated within a neural foramen. The AKA was located in the superior one-half of the foramen in 97% (110). Eighty-eight percent (100) were located in the upper third; 9% (10) were located in the middle third; and 2% (2) were located in the lower third. The AKA was never seen in the inferior one-fifth of the foramen. Eighty-eight percent (100) of the radiculomedullary arteries were located on the left while 17% (20) were located on the right. The radiculomedullary arteries were identified from T2-L3. 92% (110) were located between T8 and L1. 28% (34) were located at T10, the highest incidence., Conclusions: The AKA was overwhelmingly located in the superior aspect of the neural foramen. Contrary to traditional teaching, the safest needle placement for an epidural steroid injection, particularly at L3 and above, may not be in the superior aspect of the foramen, but rather in an inferior and slightly posterior position within the foramen and relative to the nerve., (Wiley Periodicals, Inc.)

Study Design: A retrospective review of patients with interruption of the artery of Adamkiewicz during total en bloc spondylectomy (TES)., Objective: To assess neurologic function after interruption of the artery of Adamkiewicz in TES., Summary of Background Data: The most important feeding artery of the thoracolumbar spinal cord is the great anterior radiculomedullary artery, also called the artery of Adamkiewicz. The artery of Adamkiewicz supplies the lower two-thirds of the spinal cord via the anterior spinal artery. It is naturally believed among spine surgeons that interruption of the artery of Adamkiewicz during surgeries is absolutely contraindicated. However, it is necessary to sacrifice the artery of Adamkiewicz during TES, when the tumor, by chance, exists at the level of the artery of Adamkiewicz., Methods: Between 1990 and 2009, we have performed 180 cases of TES. All cases except for few emergency cases received preoperative embolization. The artery of Adamkiewicz was verified by angiography of the segmental arteries. There were 15 patients in which the artery of Adamkiewicz was found at the levels of resected vertebrae. Interruption of the artery was performed during surgery in these 15 cases. Neurologic function was analyzed retrospectively., Results: Of the 15 patients, the Frankel grade before surgery was C in 1, D in 5, and E in 9. At follow-up, the Frankel grade was D in 1 and E in 14. There were no cases of neurologic deterioration or paralysis after TES., Conclusion: On the basis of our results of TES on up to 3 vertebrae, interruption of the artery of Adamkiewicz for TES does not adversely affect neurologic function. We advocate strongly that our surgeons are allowed to sacrifice up to 3 pairs of segmental arteries, even including the artery of Adamkiewicz, if necessary.

Object: Surgical approaches to the upper anterior thoracic spine can be a challenge. Various techniques such as transsternal routes have been employed but access to the midthoracic vertebrae is limited due to the position of the heart and great vessels. In the present study the authors' goal was to evaluate in cadavers a novel approach to the upper anterior thoracic spine., Methods: In 12 adult cadavers the majority of the left first rib was removed following infraclavicular transection of the attachment of the anterior and middle scalene muscles from this bone. Inferior retraction of the parietal pleura and lung was performed and dissection was carried out inferior to the left subclavian artery and superior and posterior to the aorta, to the anterior aspect of the upper thoracic spine., Results: The aforementioned approach and surgical corridor allowed a good access to the anterior aspect of the upper thoracic vertebrae and caudally to the inferior aspect of T-4 vertebral body in all cadavers. No obvious neurovascular injury was identified in any specimen., Conclusions: To the authors' knowledge, the method described herein has not been previously reported. Based on their cadaveric study, they believe such an approach can be used in the patients with pathology in this region of the thoracic spine. Surgical series are now needed to confirm our findings.

Object: Pedicle screws placed in the thoracic, lumbar, and sacral spine occasionally come in contact with the aorta, vena cava, or iliac vessels. When such screws are seen on postoperative imaging in an asymptomatic patient, the surgeon must decide whether it is riskier to revise the screw or to observe it. The authors hypothesized that the incidence of screw placement causing perioperative vessel injury is low and, further, that screws placed in contact with major vessels do not always result in vessel injury., Methods: A retrospective review of the operative records of 182 consecutive patients undergoing thoracic, lumbar, and lumbosacral pedicle screw fusion was performed to determine the frequency of intraoperative vessel injury. Postoperative imaging for 107 patients was available to determine the incidence of screws in contact with major vessels. Charts were examined to determine if any adverse sequelae had resulted from malpositioned screws. Patient outcomes were documented., Results: There were no intraoperative vessel injuries or deaths in 182 consecutive operations. One hundred seven patients with available postoperative films had 680 pedicle screws placed between T-3 and the sacrum during 115 operations. No patient had arterial screw penetration or deformation on postoperative imaging. Thirty-three of the 680 inserted screws were in contact with a major vessel on routine postoperative imaging. The contacted vessels included the aorta (4 cases), the iliac artery (7 cases), and the iliac veins (22 cases). Patients were followed up until death or November 2009, for a mean follow-up of 44 months (median 44 months, range 5-109 months). None of the patients with vessel contact was noted to suffer symptoms or sequelae as a result of vessel contact. Radiographic follow-up as long as 50 months after surgery revealed no detectable vessel abnormality at the contacted site., Conclusions: Placing pedicle screws in contact with major vessels is a known risk of spinal surgery. The risk of repositioning a screw in contact with a major vessel but causing no symptoms must be weighed against the relative risk of leaving it in place.

This study introduces an anatomical basis for surgeries such as thoracoscope-assisted thoracolumbar spinal anterior interbody fusion in terms of image observing and corpse specimen anatomising. The observation of the 3-dimensional computed tomography (CT) image indicates that segmental arteries are visible and run in the central supersulcus of the corresponding vertebral body's side, while the branches are invisible. The distances between adjacent segmental arteries in T(10/11), T(11/12), T₁₂/L₁, L(1/2), and L(2/3) are 23.35 ± 1.48, 25.61 ± 2.08, 29.12 ± 2.30, 32.53 ± 2.18, and 33.73 ± 2.29 (mm), respectively. And the observation by the thoracolumbar spine side of the adult corpse specimens shows that segmental arteries and veins constantly exist and run in the central supersulcus of the corresponding vertebral body's side; each segmental artery has some small branches; the zone between the upper and lower segmental arteries form a relatively non-vascular nerve safe zone, where the intervertebral space (disc) locates. The distances between adjacent segmental arteries in T(10/11), T(11/12), T₁₂/L₁, L(1/2), L(2/3) are 23.34 ± 0.78, 25.54 ± 0.85, 29.11 ± 1.01, 32.82 ± ± 1.28, and 33.71 ± 1.42 (mm), respectively. The safe zone, with the intervertebral disc as the reference mark, can provide enough operation space for surgeries like thoracoscope-assisted anterior interbody fusion and reducing damage to blood vessels as well as surgical complications. Additionally, the arrangement and distribution of segmental arteries can be clearly displayed on the 3-dimensional CT image and the result is basically consistent with that of corpse specimens. Therefore, the 3-dimensional CT image can be regarded as the reference for video-assisted thoracoscopic surgery plans.

We present a case of spinal cord compression in a 33-year-old male due to a T6-T7 paravertebral mass extending through the intervertebral foramen into the vertebral canal. Histopathological feature was consistent with an intra-vascular papillary endothelial hyperplasia. Differential diagnosis of the lesion and review of the literature are presented.

A 68-year-old woman presenting with progressive paraparesis was diagnosed with an AVF involving a previously fractured L1 vertebral body on which feeders from multiple segmental arteries converged. The most distinctive feature in our patient was that the fistula was located in the vertebral body. Transarterial embolization of the segmental arteries with coils and glue resulted in total obliteration of the fistula, which in turn resulted in symptom improvement.