Relevance of the anatomical location of the Adamkiewicz artery in spine surgery

En Bloc Surgery in the Thoracic Spine: Indications, Results, and Complications in a Series of Eighty-Five Patients Affected by Primary and Secondary Malignant Bone Tumors

BACKGROUND

En bloc resection remains the cornerstone treatment for malignant bone tumors affecting the spine. The thoracic spine poses unique challenges because of the proximity of crucial structures. This study assesses outcomes of patients who underwent en bloc spondylectomy for malignant bone tumors at the thoracic level.

METHODS

We retrospectively reviewed 85 cases of primary and secondary bone tumors in the thoracic spine, undergoing en bloc spondylectomy from 1996 to 2016. Evaluation encompassed clinical presentation, tumor characteristics, surgical outcomes, complications, survival, and recurrence.

RESULTS

Of 85 patients, 40 presented directly, whereas 45 had undergone previous intralesional surgery. Chondrosarcoma and chordoma comprised the most prevalent primary histologic types; thyroid and kidney carcinomas were the most frequent secondary tumors. Pain was reported in 75 patients at diagnosis. Margins were adequate in 54 cases and intralesional in 31. Immediate postoperative deaths amounted to 4. Major complications included substantial blood loss, neurologic deterioration, and paraplegia. The 5-year local recurrence-free survival was 58.7%, significantly influenced by the surgical margin: patients with wide margins experienced a 5-year local recurrence-free survival of 85.7%, whereas those with marginal and intralesional margins had rates of 56.7% and 45.6%, respectively; overall recurrence was 22.3%, with no notable disparities between previously treated and untreated patients. The 5-year overall survival was 63.2% and 56.2% for primary and secondary tumors, respectively. The overall survival was not significantly influenced by surgical margins.

CONCLUSIONS

Managing malignant thoracic bone tumors poses significant challenges. This study underscores the criticality of achieving adequate margins, particularly after previous intralesional approaches.

Unraveling the enigma of Adamkiewicz: exploring the prevalence, anatomical variability, and clinical impact in spinal embolization procedures for bone metastases

BACKGROUND

The artery of Adamkiewicz (AKA) is vital for spinal cord blood supply. Its role in embolization procedures for bone metastases can cause serious complications. We explored its prevalence, anatomical variation, and effect on spinal embolization using N-butyl cyanoacrylate (NBCA) in patients with bone metastases.

PURPOSE

To understand the impact and variability of AKA in spinal embolizations in cases of bone metastases to reduce complications and improve patient outcomes.

MATERIAL AND METHODS

We examined data from 454 patients who underwent spinal embolization with NBCA between 2009 and 2018. The presence, anastomoses, and tumor features of AKA were assessed via pre-procedure imaging and angiography. Complications were classified per the CIRSE Classification System.

RESULTS

AKA was found in 22.8% of patients, predominantly left-sided and originating from T8 to L1. Direct and indirect anastomoses were present in 66.6% and 33.4% of patients, respectively. Extra-compartmental invasion was linked with direct anastomosis (P = 0.004). High-grade complications were rare but included one instance of bilateral lower limb paralysis. Partial embolization was necessary in 22.8% of cases due to AKA.

CONCLUSION

The study underscores the need for rigorous preoperative evaluation of AKA origin and anastomoses in patients undergoing spinal embolization for bone metastases. Given the significant presence of AKA and related anastomoses, especially with renal extra-compartmental tumors, caution is advised to reduce complications and optimize patient outcomes. Further research is required for best practice guidelines involving bone metastases and AKA.

Preoperative Spinal Angiography for Thoracic Neuroblastoma: Impact of Identification of the Adamkiewicz Artery on Gross Total Resection and Neurological Sequelae

BACKGROUND

Patients with thoracic neuroblastoma (TNB) are at high risk of postoperative neurologic complications due to iatrogenic lesions of the artery of Adamkiewicz (AKA). The role of performing a preoperative spinal angiography (POSA) in these patients must be clarified. The present study sought to further understand the relationship between POSA and TNB, as well as the effects of identifying the AKA on surgical excision and neurological consequences.

METHODS

Data from patients with TNB who underwent POSA between November 2015 and February 2022 at our tertiary pediatric center were retrospectively analyzed.

RESULTS

Six patients were identified, five of whom (83%) were considered eligible for surgical excision. Gross total resection (GTR) was achieved in three patients (60%), which included two patients with an AKA contralateral to the tumor, and one with an homolateral AKAl. After a median follow-up of 4.1 years from diagnosis, no patients developed neurological complications; five (83%) were alive and well, and one died from refractory recurrence.

CONCLUSIONS

Among patients with TNB, POSA was useful for identifying the AKA and defining the optimal surgical strategy. POSA should be considered in the preoperative evaluation of TNB to increase the likelihood of GTR and reduce the threats of iatrogenic neurologic sequelae.

Identification of the Magna Radicular Artery Entry Foramen and Adamkiewicz System: Patient Selection for Open versus Full-Endoscopic Thoracic Spinal Decompression Surgery

BACKGROUND

Casually cauterizing the radicular magna during routine thoracic discectomy may have dire consequences.

METHODS

We performed a retrospective observational cohort study on patients scheduled for decompression of symptomatic thoracic herniated discs and spinal stenosis who underwent a preoperative computed tomography angiography (CTA) to assess the surgical risks by anatomically defining the foraminal entry level of the magna radicularis artery into the thoracic spinal cord and its relationship to the surgical level.

RESULTS

Fifteen patients aged 58.53 ± 19.57, ranging from 31 to 89 years, with an average follow-up of 30.13 ± 13.42 months, were enrolled in this observational cohort study. The mean preoperative VAS for axial back pain was VAS of 8.53 ± 2.06 and reduced to a postoperative VAS of 1.60 ± 0.92 (p < 0.0001) at the final follow-up. The Adamkiewicz was most frequently found at T10/11 (15.4%), T11/12 (23.1%), and T9/10 (30.8%). There were eight patients where the painful pathology was found far from the AKA foraminal entry-level (type 1), three patients with near location (type 2), and another four patients needing decompression at the foraminal (type 3) entry-level. In five of the fifteen patients, the magna radicularis entered the spinal canal on the ventral surface of the exiting nerve root through the neuroforamen at the surgical level requiring a change of surgical strategy to prevent injury to this important contributor to the spinal cord's blood supply.

CONCLUSIONS

The authors recommend stratifying patients according to the proximity of the magna radicularis artery to the compressive pathology with CTA to assess the surgical risk with targeted thoracic discectomy methods.

Preoperative spinal angiography decreases risk of spinal ischemia in pediatric posterior thoracic tumor resection

PURPOSE

Resection of pediatric posterior thoracic tumors (PTTs) can be complicated by Artery of Adamkiewicz (AKA) injury. Post-op spinal ischemia occurs in approx. 3.2% of patients, typically due to iatrogenic vascular injury. Pre-op angiography (PSA) may help to avoid this complication. Herein, we aim to evaluate outcomes after initiation of routine PSA prior to PTT resection.

METHODS

A single-institution retrospective review identified 25 children (< 18 years) treated for PTTs from 2009 to 2021. PTTs included: posterior mediastinum, paraspinal thorax and posterior chest wall tumors. PSA patients were compared to those without pre-operative angiography (NA). Demographics, perioperative and long-term outcomes and event-free survival (EFS) were assessed.

RESULTS

Prior to 2012, eleven patients were treated without PSA. However, the last developed post-operative paraplegia secondary to spinal ischemia. Since this event, PSA has become routine for all PTTs (n = 14) identifying six AKAs and nine accessory spinal arteries. Resection was performed in ten (90.1%) NA patients and eight (57.1%) PSA patients. Based on PSA findings, resection was not offered to six patients and planned partial resection was performed in three patients. Five PSA patients required radiation therapy for local control vs two NA patients. There were no differences in recurrence or overall EFS.

CONCLUSION

PSA aids in identifying patients with high-risk thoracic vascular anatomy and may prevent risk of post-operative paraplegia associated with PTT resection.

Anterior spine surgery for the treatment of complex spine pathology: a state-of-the-art review

The use of anterior spinal surgery for the treatment of spinal pathology has experienced a dramatic increase over the past decade. Long relegated to treat complicated anterior pathologies it has returned to mainstream spine surgery techniques for all types of conditions, providing a significant boost to the spine surgeons' armamentarium to address a wide variety of types of spinal diseases more effectively. Anterior surgery is useful whenever there is significant spinal pathology that requires direct visualization of the anterior vertebral column to best restore spinal alignment, structural integrity and neurologic function. These pathologies include spinal deformities, tumors, burst fractures, infections, vertebral avascular necrosis, pseudoarthrosis and other miscellaneous indications. Currently available approaches to the spine include transabdominal, paramedian retroperitoneal, lateral oblique retroperitoneal, thoracotomy, and thoracolumbar extensile. Most of the lumbar approaches are now done through a muscle splitting, minimalistic approach that has decreased their morbidity or more recently via tubular approaches, such as lateral lumbar interbody fusions or other ante-psoas approaches. New retractors, instrumentation, hyperlordotic implants, approved biologics and even image guidance for disc preparation and precise implant placement are all recent advances that will hopefully improve surgical outcomes in patients following anterior spinal surgery. Most importantly, these approaches require added expertise and training with a dedicated team consisting of an anteriorly trained spine surgeon working simultaneously with a dedicated vascular surgeon to ensure maximum safety and superior patient outcomes. This state of the review is dedicated to familiarizing practicing spine surgeons with the most commonly used anterior spinal approaches along with cutting-edge instrumentation and fusion techniques to improve their options for the treatment of difficult spinal pathologies.

Treatment of a severe distal thoracic and abdominal coarctation with cutting balloon and stent implantation in an infant: From fetal diagnosis to adolescence

Background and Aims

Abdominal coarctations are rare. Surgical treatment is difficult and requires re‐interventions to adjust the graft material to patient growth. We report effective treatment by interventional catheterization in an infant with the concern to allow adjustment for growth and prevention of vessel damage.

Methods and Results

After the diagnosis of abdominal coarctation at 27 weeks of gestation, an infant developed hypertension (170/70 mmHg) at 3 months of age despite medical therapy. Angio CT confirmed a 2 mm diameter, 2.3‐cm‐long coarctation of the descending aorta. At 4 months, a dilatation was performed using a 3 mm cutting balloon and a 5 mm Opta® balloon, Cordis®. Two noncovered Palmaz® Genesis™ XD PG1910P stents were required to keep the aortic lumen open. At 15 months, an Adventa™ V12 vascular 12 × 61 mm long covered stent was implanted to exclude an aneurysm which developed between the two stents. At 3 and 9.5 years, the stents were further dilated with a high‐pressure balloon to reach 11 mm aortic diameter with no residual pressure gradient, and normal blood pressure.

Conclusions

The use of cutting balloons and stent implantation is an effective way to relieve severe obstruction in middle aortic syndrome in neonates. The technical issues encountered were the need for a low profile sheath and material to avoid femoral artery damage, and the need to use stents that can be further expanded to adult size.

A rare case of giant calcified thoracic disc herniation, OPLL and OLF: how I do it

BACKGROUND

Thoracic myelopathy can have different aetiologies. Based on the location and on the nature of spinal cord compression, different surgical approaches may be indicated.

METHOD

We present a rare case of thoracic myelopathy caused by the coexistence of a giant disc herniation, OPLL and OLF, and we describe the surgical approach, with a focus on technical nuances and strategies to avoid complications.

CONCLUSION

Careful presurgical planning and microsurgery are fundamental in achieving a satisfactory spinal cord decompression. IONM, endoscopy-assisted microsurgery and intraoperative navigation can enhance the safety of surgery and the extent of safe surgical decompression.

Vertebral Metastases: Minimally Invasive Percutaneous Thermal Ablation

This article provides a step-by-step guide for minimally invasive percutaneous image-guided thermal ablation for treatment of vertebral metastases. Such interventions have proved safe and effective in management of selected patients with spinal metastases primarily to achieve pain palliation and local tumor control. Particular attention to patient selection guidelines, details of procedure techniques, thermal protection, adequacy of treatment, recognition and management of potential complications, and post-ablation imaging are essential for improved patient outcomes.

French Multidisciplinary Approach for the Treatment of MSK Tumors

Several interventional treatments have recently been integrated into the therapeutic armamentarium available for the treatment of bone tumors. In some scenarios (e.g., osteoid osteoma), interventional treatments represent the sole and definitive applied treatment. Due to the absence of widely shared protocols and the complex multivariate scenarios underlying the clinical presentation of the remaining bone tumors including metastases, therapeutic strategies derived from a multidisciplinary tumor board are essential to provide effective treatments tailored to each patient. In the present review, we present the multidisciplinary therapeutic strategies commonly adopted for the most frequent bone tumors.

Spinal cord infarction six months after thoracic endovascular aortic repair- A case report

Spinal cord infarction is reported to account for less than 1% of all strokes and is a relatively rare disease. In recent years, thoracic endovascular aortic repair (TEVAR) has become a common treatment for aortic aneurysms, and spinal cord ischemia is one of its complications. Most cases occur in the perioperative period; however, a few cases have been reported in the chronic stage. Here, we report a case of spinal cord infarction, 6 months after TEVAR. A 77-year-old man experienced sudden onset paraparesis following dumbbell exercises and defecation. He had a history of an infectious thoracoabdominal aortic aneurysm treated by TEVAR 6 months prior. Paralysis and disturbance of the thermal pain and tactile sensations of the lower limbs were observed, but proprioception and deep sensation were preserved. Computed tomography (CT) showed no evidence of intraspinal hemorrhage, new aortic dissection, or endoleak around the aortic stent placed from Th11 to L3. Magnetic resonance imaging (MRI) showed intramedullary hyperintensity from Th11 to the conus 2 days after onset. Anticoagulant therapy and rehabilitation were performed, and the lower-limb muscle strength gradually improved. After aortic stenting, particularly including the level of the Adamkiewicz artery, the risk of spinal cord ischemia must be monitored, because spinal circulation depends on collateral circulation.

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.

Etiology and Outcomes of Spinal Cord Infarct: A Case Series From a Level 1 Trauma Center

STUDY DESIGN

Retrospective study.

OBJECTIVES

To evaluate the demographics, prevalence, etiology, severity, and outcomes of spinal cord injuries (SCIs) resulting from ischemic infarction.

METHODS

All patients with SCI and a diagnosis of cord infarct who were admitted to the inpatient rehabilitation unit at a level 1 trauma center from January 2003 to January 2014 were identified using an administrative billing database. Outcomes measures were evaluated.

RESULTS

Among 685 unique SCI patients who were identified, 30 (4.4%) had SCI due to spinal ischemic infarction. The mean age was 59 years (range 17-80 years). Fifty percent of patients had ASIA (American Spinal Injury Association) A and B severity. Most common causes were the following: 6 (20%) abdominal aortic aneurysm (AAA) repairs, 6 (20%) arteriovenous fistulas, and 6 (20%) with an unknown cause. Surgical complications led to 4 (13.3%) cord infarcts and was associated with a higher severity of injury (P = .02) compared with other etiologies. Other causes included systemic hypotension, AAA rupture, trauma, diabetic ketoacidosis, and after radiation therapy. At follow-up, 6 (20%) of patients were able to ambulate normally without assistance, 7 (23.3%) were ambulating with assistance, and 17 (56.7%) were still wheelchair bound. Clinical improvement in ambulatory status was noted in 6 (20%) patients and was associated with less severe initial injury (P = .02).

CONCLUSIONS

While the existing literature associates spinal cord infarction with aortic pathologies and surgery, these caused less than 30% of cases, while nonaortic surgical complications were associated with the most severe injuries. Outcomes were worse than previously reported in the literature.

The relevance of the artery of Adamkiewicz for microsurgical resection of spinal tumors- short overview and case series: Technical note

INTRODUCTION

There is of major interest to know the exact anatomical location of artery of Adamkiewicz (AKA) for many spinal microsurgical procedures, so as to avoid postoperative ischemia of the spinal cord, with further devastating clinical impact.

METHODS AND RESULTS

We detail the interest of preoperative angiography for medullary lesions in our experience. We further report two cases where the AKA was located at the same level and side with the treated lesion. The first case underwent an intracapsular decompression. The second patient undertook radiosurgery by Cyberknife.

CONCLUSION

For spinal tumor where the AKA is exactly on the same level and side, an intracapsular decompression can be safely performed, with an immediate decrease of the symptomatic mass effect, while decreasing the risk of neurological injury. A second valuable alternative in such situations can also be radiosurgery, for small to medium size tumors. In our experience, this proved safe and effective both for tumor and eventual pain control.

Unilateral Nerve Root Ligation for Multilevel Vertebral Column Resection After Fixed Post-infectious Deformity

Kyphotic deformity is a well-recognized complication of thoracic vertebral osteomyelitis, often requiring multi-level vertebral column resection for mobilization of the spine and reduction of the deformity. We present a case of severe post-infectious kyphosis treated with multi-level vertebral column resection via a unilateral approach. We obtained excellent decompression and deformity correction without neurologic decline. We review relevant literature regarding spinal cord blood supply and known potential complication of nerve root ligations.

Trans-thoracic versus retropleural approach for symptomatic thoracic disc herniations: comparative analysis of 94 consecutive cases

PURPOSE

The authors illustrate their results in the surgical treatment of symptomatic thoracic disc herniations (TDHs) by comparing the traditional open to the less invasive retropleural lateral approaches.

METHODS

Retrospective review of 94 consecutive cases treated at a single Institution between 1988 and 2014. Fifty-two patients were males, 42 females, mean age was 53.9 years. Mean follow-up was 46.9 months (12-79 months). 33 patients were diagnosed with a giant thoracic disc herniation (GTDH). Upon admission, the most common symptoms were: motor impairment (91.4%, n = 86), neuropathic radicular pain with VAS > 4 (50%), bladder and bowel dysfunction (57.4% and 41.4% respectively) and sensory disturbances (29.7%). The surgical approach was based upon level, laterality and presence or absence of calcified lesions.

RESULTS

Decompression was performed in 7 cases via a thoraco-laparo-phrenotomy and in 87 cases via an antero-lateral thoracotomy. Out of the latter cases, 49 (56%) were trans-thoracic trans-pleural approaches (TTA) and 38 (44%) were less invasive retropleural approaches (MIRA). At follow-up, there were 59.5% neurologically intact patients according to the McCormick Scale, while 64.8% and 67% had no bladder or bowel dysfunction respectively. Complications occurred in 24 patients (25.5%). Pulmonary complications were the commonest (12.7%) with pleural effusion being significantly more common in patients treated with TTA compared to MIRA (20% vs 5.2%: X² 4.13 P:0.042). Severe post-operative neuralgia (VAS 7-10) was also significantly more frequent in the TTA group (22.4% vs 2.6% X² 7.07 p 0.0078).

CONCLUSIONS

MIRA is a safe and effective technique to obtain adequate TDH decompression and is associated with lower morbidity compared to TTA.

Spinal Tumor Ablation: Indications, Techniques, and Clinical Management

Percutaneous thermal ablation has proven to be safe and effective in the management of patients with spinal tumors. Such treatment is currently proposed following the decision of a multidisciplinary tumor board to patients with small painful benign tumors such as osteoid osteoma or osteoblastoma, as well as carefully selected patients presenting with spinal metastases. In both scenarios, in order to provide a clinically effective procedure, ablation is often tailored to the specific patients' clinical needs and features of the target tumor. In this review, we present the most common clinical contexts in which spine ablation may be proposed. We scrutinize technical aspects and challenges that may be encountered during the procedure, as well as offering insight on follow-up and expected outcomes.

A role for spinal cord hypoxia in neurodegeneration

The vascular system of the spinal cord is particularly complex and vulnerable. Damage to the main vessels or alterations to the regulation of blood flow will result in a reduction or temporary cessation of blood supply. The resulting tissue hypoxia may be brief: acute, or long lasting: chronic. Damage to the vascular system of the spinal cord will develop after a traumatic event or as a result of pathology. Traumatic events such as road traffic accidents, serious falls and surgical procedures, including aortic cross-clamping, will lead to an immediate cessation of perfusion, the result of which may not be evident for several days, but may have long-term consequences including neurodegeneration. Pathological events such as arterial sclerosis, venous occlusion and spinal cord compression will result in a progressive reduction of blood flow, leading to chronic hypoxia. While in some situations the initial pathology is exclusively vascular, recent research in neurodegenerative disease has drawn attention to concomitant vascular anomalies in disorders, including amyotrophic lateral sclerosis, spinal muscular atrophy and muscular sclerosis. Understanding the role of, and tissue response to, chronic hypoxia is particularly important in these cases, where inherent neural damage exacerbates the vulnerability of the nervous system to stressors including hypoxia.

Artery of Adamkiewicz: a meta-analysis of anatomical characteristics

PURPOSE

The artery of Adamkiewicz (AKA) provides the major blood supply to the anterior thoracolumbar spinal cord and iatrogenic injury or inadequate reconstruction of this vessel during vascular and endovascular surgery can result in postoperative neurological deficit due to spinal cord ischemia. The aim of this study was to provide comprehensive data on the prevalence and anatomical characteristics of the AKA.

METHODS

An extensive search was conducted through the major electronic databases to identify eligible articles. Data extracted included study type, prevalence of the AKA, gender, number of AKA per patient, laterality, origin based on vertebral level, side of origin, morphometric data, and ethnicity subgroups.

RESULTS

A total of 60 studies (n = 5437 subjects) were included in the meta-analysis. Our main findings revealed that the AKA was present in 84.6% of the population, and patients most frequently had a single AKA (87.4%) on the left side (76.6%) originating between T8 and L1 (89%).

CONCLUSION

As an AKA is present in the majority of the population, caution should be taken during vascular and endovascular surgical procedures to avoid injury or ensure proper reconstruction. All surgeons operating in the thoracolumbar spinal cord should have a thorough understanding of the anatomical characteristics and surgical implications of an AKA.

Postoperative urinary retention or difficulties to empty the bladder in young patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis

BACKGROUND

Postoperative urinary retention has been reported to affect up to 27% of adults undergoing degenerative lumbar spine surgery and approximately one-third of children undergoing lower-extremity orthopedic surgery. No data exist on the incidence and risk factors of postoperative urinary tract retention/difficulties to empty the bladder in young patients undergoing instrumented posterior spinal fusion. We aimed to characterize incidence, risk factors and treatment of postoperative urinary retention (POUR) and difficulties to empty the bladder in young patients undergoing posterior spinal fusion (PSF) for idiopathic scoliosis.

METHODS

One hundred and eleven consecutive patients (mean age 16years [range, 11-21years], 81 females and 30 males) undergoing PSF for adolescent idiopathic scoliosis were screened after removal of urinary catheter postoperatively for inability to void and residual volume of urinary bladder. The latter was measured using ultrasound on two separate occasions. POUR and the need for intermittent catheterization were defined as an inability to void after catheter removal and documented full bladder with ultrasound (a residual of 300mL or more) or a significant residual volume after voiding (>2mL/kg or >100mL).

RESULTS

Fifty-one (46%) of the patients were either unable to void or had a clinically significant amount of residual volume after voiding. These fifty-one patients required intermittent catheterization for a mean of two days. Thirty patients (27%) had POUR, a residual volume of 300mL or more. Two (1.8%) patients experienced urinary tract infection postoperatively. Patients with urinary retention had a significantly higher mean intraoperative blood loss (mean 626mL vs. 464mL; p=0.020) and longer operation time (mean 3.3h vs. 2.8h; p=0.009) as compared with those not having urinary retention. In multivariate analyses the main risk factor for urinary retention was male gender (odds ratio 3.2 [95% confidence interval 1.1-9.2], p=0.028).

CONCLUSIONS

Postoperative voiding difficulties affect almost half of the patients with age under 21years undergoing PSF for idiopathic scoliosis. The main risk factors were increased intraoperative blood loss, longer length of surgery and male gender. POUR should be actively screened and treated in this patient population.

LEVEL OF EVIDENCE

Prospective Cohort Study II.

The pathologic mechanisms underlying lumbar distraction spinal cord injury in rabbits

BACKGROUND CONTEXT

A reliable experimental rabbit model of distraction spinal cord injury (SCI) was established to successfully simulate gradable and replicable distraction SCI. However, further research is needed to elucidate the pathologic mechanisms underlying distraction SCI.

PURPOSE

The aim of this study was to investigate the pathologic mechanisms underlying lumbar distraction SCI in rabbits.

STUDY DESIGN

This is an animal laboratory study.

METHODS

Using a self-designed spine distractor, the experimental animals were divided into a control group and 10%, 20%, and 30% distraction groups. Pathologic changes to the spinal cord microvessels in the early stage of distraction SCI were identified by perfusion of the spinal cord vasculature with ink, production of transparent specimens, observation by light microscopy, and observation of corrosion casts of the spinal cord microvascular architecture by scanning electron microscopy. Malondialdehyde (MDA) and superoxide dismutase (SOD) concentrations in the injured spinal cord tissue were measured after 8 hours.

RESULTS

With an increasing degree and duration of distraction, the spinal cord microvessels were only partially filled and had the appearance of spasm until rupture and hemorrhage were observed. The MDA concentration increased and the SOD concentration decreased in the spinal cord tissue.

CONCLUSIONS

Changes to the internal and external spinal cord vessels led to spinal cord ischemia, which is a primary pathologic mechanism of distraction SCI. Lipid peroxidation mediated by free radicals took part in secondary pathologic damage of distraction SCI.

Management of Thoracic Disc Herniations via Posterior Unilateral Modified Transfacet Pedicle-Sparing Decompression With Segmental Instrumentation and Interbody Fusion

STUDY DESIGN

Retrospective consecutive case series.

OBJECTIVE

The objective of this case series was to demonstrate the safety of a modified transfacet pedicle-sparing decompression and instrumented fusion in patients with thoracic disc herniations (TDHs).

METHODS

Consecutive patients undergoing operative management of TDH from July 2007 to December 2011 using a posterior unilateral modified transfacet pedicle-sparing approach were identified. All patients underwent open or minimally invasive modified transfacet pedicle-sparing discectomy and segmental instrumentation with interbody fusion, performed by four different surgeons. Pre- and postoperative visual analog scale (VAS) pain scores, Nurick grade, and American Spinal Injury Association Impairment Scale (AIS) were analyzed from a retrospective chart review. Estimated blood loss and complications were also obtained.

RESULTS

Fifty-one patients were included that had operations for TDH. Thirty-nine patients had single level decompression and 12 had multilevel decompression. The total number of levels operated on was 64. Five patients were treated with minimally invasive surgery. A herniated disc level of T11-12 (n = 17) was treated most often. One major complication of epidural hematoma occurred. Minor complications such as malpositioned hardware, postoperative hematoma, wound infection, pseudoarthrosis, and pulmonary complications occurred in a few patients. Follow-up ranged from 1 to 46 months with 1 patient lost to follow-up. From preoperative to final postoperative: mean VAS scores improved from 8.31 to 4.05, AIS in all patients remained stable or improved, and Nurick scores improved from 3 to 2.6 on average. No intraoperative or permanent neurological deficit occurred.

CONCLUSION

In our surgical series, 51 consecutive patients underwent modified transfacet pedicle-sparing approach to TDHs and experienced improvement of functional status as well as improvement of objective pain scales with no neurological complications. The posterior unilateral modified transfacet pedicle-sparing decompression and instrumented fusion approach to the thoracic spine is a safe and reproducible procedure for the treatment of TDHs.

Electrophysiological monitoring during preoperative angiography to guide decisions regarding permanent occlusion of major radicular arteries in patients undergoing total en bloc spondylectomy

OBJECTIVE

Preoperative embolization is performed before spine tumor surgery when significant intraoperative hemorrhage is anticipated. Occlusion of radicular and segmental arteries may result in spinal ischemia. The goal of this study was to check whether neurophysiological monitoring during preoperative angiography in patients scheduled for total en bloc spondylectomy (TES) of spine tumors improves the safety of vessel occlusion.

METHODS

This was a case series study of patients who underwent tumor embolization under somatosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring in preparation for TES in treating spine tumors. The angiography findings, the embolized vessels, and the results are presented.

RESULTS

Five patients whose ages ranged from 33 to 75 years and who had thoracic spine tumors are reported. Four patients suffered from primary tumor and 1 patient had a metastatic tumor. Radicular arteries at the tumor level, 1 level above, and 1 level below were permanently occluded when SSEPs and MEPs were preserved during temporary occlusion. No complications were encountered during or after the angiography procedure and embolization.

CONCLUSIONS

Temporary occlusion with electrophysiological monitoring during preoperative angiography may improve the safety of permanent radicular artery occlusion, including the artery of Adamkiewicz in patients undergoing TES for the treatment of spine tumors.

Microsurgical anatomy of the Adamkiewicz artery-anterior spinal artery junction

PURPOSE

The aim of this study is to describe the anterior spinal artery-Adamkiewicz artery (ASA-AKA) junction and establish a classification allowing defining the neurological risk in either thoracoabdominal aorta aneurysm treatment and in anterior or transforaminal thoracolumbar spine surgery.

METHODS

Fifteen spinal cords of fresh cadavers were dissected. Both lumbar arteries and ASA were injected with strongly diluted red-colored silicon.

RESULTS

The dural crossing of AKA was located on the left side in 86 % of cases, between T8 and T10 in 73.33 % of cases and L1-L2 in 26.67 % of cases. The average diameter of the ascending branch of AKA was 1.10 mm (range 0.8-1.9 mm), and its average length was 30.27 mm (range 12.3-60 mm). The AKA's arch average diameter was 11.3 mm (range 9-20 mm) with an open downward angle average of 20.1° (range 11°-30°). The descending branch of AKA which was a continuation of ASA had an average diameter of 1.33 mm (range 0.8-1.86 mm). The ASA at the top of the arch had an average diameter of 0.74 mm (range 0.2-1.77 mm). According to these findings, we have proposed a new classification with two types of junctions. The type I and its variant correlated to high neurological risk were present in 93.33 % of cases. The type II, correlated to medium or low neurological risk, was present in 6.67 % of cases.

CONCLUSION

These anatomical findings allow a planning of the neurological risk before thoracoabdominal aorta aneurysm or thoracolumbar anterior or transforaminal spine surgery.

Anatomia da circulação medular

ResumoA intrincada anatomia tridimensional da irrigação medular é frequentemente explanada na literatura com diferentes nomenclaturas e devido a sua alta relevância no estudo da isquemia medular, o estudo da terminologia se faz necessário para melhor compreensão do tema. A artéria de Adamkiewicz, também chamada de artéria radicular magna, é a via principal. Foi realizada a revisão da literatura com equiparação das nomenclaturas utilizadas e elaboração de descrição acurada e sumarizada do conhecimento atual sobre a vascularização medular.

Management of thoracolumbar spine fractures with neurologic disorder

Thoracic and lumbar fractures represent approximately 50% of neurologic spinal trauma. They lead to paraplegia or cauda equina syndrome depending on the level injured. In the acute phase, the extension of spinal cord lesions should be limited by immediately treating secondary systemic injury factors. Quick recovery of hemodynamic stability, with mean arterial blood pressure>85 mm Hg, appears essential. There is no clinical evidence in favor of high-dose corticosteroid protocols. Their effect on neurologic recovery is unproven, whereas they lead to a higher rate of secondary septic and pulmonary complications. Incomplete deficits (ASIA B-D) require urgent surgery. There is no consensus with regard to complete paraplegia (ASIA A), but early surgery can enable neurologic recovery in some cases. The principle of surgical treatment is based on spinal cord decompression, instrumentation and fracture reduction. Early stabilization of the spine improves respiratory function and shortens the duration of mechanical ventilation and thus intensive care unit stay. Depending on the severity of associated lesions, early surgery within 48 hours is beneficial in polytrauma patients. Percutaneous instrumentation combined with mini-open posterior decompression stabilizes the spine, limiting approach-related morbidity.

[Postoperative spine]

Approximately 15-30 % of surgical procedures involving the lumbar spine are associated with complications that require further diagnostic work-up. The choice of imaging modality for postoperative complications depends on the extent, pattern and temporal evolution of the postoperative neurological signs and symptoms as well as on the preoperative clinical status, the surgical procedure itself and the underlying pathology. The interpretation of imaging findings, in particular the distinction between postoperative complications and normally expected nonspecific postoperative imaging alterations can be challenging and requires the integration of clinical neurological information and the results of laboratory tests. The combination of different imaging techniques might help in cases of equivocal imaging results.

Anterior spinal artery syndrome: reversible paraplegia after minimally invasive spine surgery

Background Context. Percutaneous balloon kyphoplasty is an established minimally invasive technique to treat painful vertebral compression fractures, especially in the context of osteoporosis with a minor complication rate. Purpose. To describe the heparin anticoagulation treatment of paraplegia following balloon kyphoplasty. Study Design. We report the first case of an anterior spinal artery syndrome with a postoperative reversible paraplegia following a minimally invasive spine surgery (balloon kyphoplasty) without cement leakage. Methods. A 75-year-old female patient underwent balloon kyphoplasty for a fresh fracture of the first vertebra. Results. Postoperatively, the patient developed an acute anterior spinal artery syndrome with motor paraplegia of the lower extremities as well as loss of pain and temperature sensation with retained proprioception and vibratory sensation. Complete recovery occurred six hours after bolus therapy with 15.000 IU low-molecular heparin. Conclusion. Spine surgeons should consider vascular complications in patients with incomplete spinal cord syndromes after balloon kyphoplasty, not only after more invasive spine surgery. High-dose low-molecular heparin might help to reperfuse the Adamkiewicz artery.

Novel application of 3-dimensional rotational C-arm conebeam computed tomography angiography for metastatic hypervascular tumor mass in the spine

STUDY DESIGN

This is a case report.

OBJECTIVE

To report a 3-dimensional (3D) rotational C-arm conebeam computed tomography (CT) (DynaCT) angiography generating computed tomographic data concurrently with spinal angiographic datasets. This technology allowed 3D modeling of the anterior spinal arterial supply in juxtaposition to a hypervascular tumor mass, thus affording unprecedented guidance in presurgical planning.

SUMMARY OF BACKGROUND DATA

An enhanced demonstration of spatial relationships between the vascular elements and their adjacent soft-tissue structures is needed to visualize the minute anterior spinal artery optimally.

METHODS

A 76-year-old male with a history of renal cell carcinoma metastasis to the T6 vertebra 1 year prior, presented with worsening myelopathy caused by severe spinal cord compression at T6 level, and a plan for surgical decompression was established. Because of the hypervascular nature of this renal cell carcinoma metastasis, preoperative embolization was requested to minimize blood loss during the operation. A digital subtraction angiogram identified the major arterial contribution to the tumor to also supply the radiculomedullary branch to the anterior spinal artery. To further characterize this blood supply, a rotational DynaCT angiography was performed.

RESULTS

The rotationally acquired data were processed generating volumetric CT datasets demonstrating the 3D relationships of the anterior spinal artery, the blood supply to the tumor and the adjacent soft-tissue and bony structures. A shared blood supply to both the tumor mass and the anterior spinal artery from the left T6 segmental artery was confirmed. The dual nature of this blood supply presented increased risk of ischemic spinal cord injury by possible nontarget embolization. Therefore, the embolization was deferred.

CONCLUSION

The DynaCT angiography precisely characterized the complex blood supply of a hypervascular vertebral tumor mass in relation to a shared arterial supply to the thoracic spinal cord. The optimal visualization properly aided presurgical planning.

LEVEL OF EVIDENCE

N/A.

Acute lumbar radiculopathy with weak legs

BACKGROUND

Inferior vena cava thrombosis is a rare but important cause of acute low back pain and lumbar radiculopathy. Failure to diagnose and treat this condition could result in propagation of the thrombosis, resulting in fatal pulmonary embolism.

CASE REPORT

We report the first known case of inferior vena cava thrombosis in a postpartum woman presenting with acute lumbar radiculopathy and weak legs. She was successfully treated with i.v. heparin and oral anticoagulation.

CONCLUSIONS

Inferior vena cava thrombosis is a rare cause of acute lumbar radiculopathy, but is in the differential diagnosis to consider, especially in those patients at increased risk of thrombosis.

Transient neurological deficit following midthoracic decompression for severe stenosis: a series of three cases

PURPOSE

To report three cases of transient perioperative neurological deficit in the absence of direct cord insult following decompression of the severely stenotic thoracic spine.

METHODS

The clinical and radiographic electronic medical records of three patients who underwent decompression for severe midthoracic stenosis with transient neurological deficits perioperatively were reviewed. The cases are presented with consideration of possible underlying mechanisms and multimodality intraoperative monitoring (IOM) findings.

RESULTS

Two patients had neurologic changes on IOM and Stagnara wake-up test, the remaining patient had absent motor and sensory potentials at baseline and throughout the case. IOM changes were observed immediately following decompression in the absence of direct cord insult or displacement. Postoperatively all patients experienced neurological motor deficits which presented as complete paralysis of the right lower extremity in two of the patients and the left lower extremity in one patient. The deficit was transient-improvement of motor strength occurred between 1 and 13 months of follow-up in all patients.

CONCLUSION

Decompression of a severely stenotic region of the thoracic spinal cord may lead to a complete yet transient motor deficit in the perioperative period in the absence of direct mechanical cord insult. Potential etiologies include ischemia-reperfusion injury, microthrombi, and altered perfusion due to internal recoil of spinal cord architecture following decompression. IOM may show conspicuous findings in such events, however, may not be relied upon when baseline potentials are sub-optimal. Recognition of this short-lived neurological deficit following decompression of the severely stenotic thoracic spine will improve preoperative patient counseling and merits further study for determination of the precise pathophysiology.

Is preoperative embolization a prerequisite for spinal metastases surgical management?

BACKGROUND

Preoperative embolization decreases the intraoperative risk of hemorrhage in spinal decompression surgery of hypervascular metastases such as renal cell carcinoma. There is no consensus concerning embolization in other metastases. The purpose of this study was to compare the intraoperative amount of blood loss in embolized versus non-embolized patients, seeking for differences depending on the primary tumor and the extent of surgery.

PATIENTS AND METHODS

Ninety-three patients, average age 60.5 years, were operated. The origins of metastases were: 28 breast cancer (30.1%), 19 pulmonary carcinoma (20.4%), 16 renal cell carcinoma (17.2%), 30 other cancers (32.3%). Surgical procedures were: 52 thoracolumbar laminectomies with instrumentation, 29 thoracolumbar corpectomies or vertebrectomies, 12 cervical corpectomies. A preoperative microsphere embolization was performed in 35 patients. Blood loss was evaluated by: blood volume in surgical aspiration devices, number of transfused packed red blood cells units and hemoglobin variation during surgery.

RESULTS

Renal metastases were systematically embolized. In the breast group, there was no significant difference (P>0.05) in blood loss between embolization versus non-embolization. In the pulmonary group and in other metastases, no difference was found either. The extent of surgery (corpectomy/vertebrectomy versus thoracolumbar instrumentation and cervical corpectomy) increased bleeding: breast 1775ml versus 778ml and 600ml respectively (P=0.048), pulmonary 2500ml versus 430ml and 180ml (P=0.020), renal 3346ml versus 1175ml and 780ml (P=0.036) and others 1550ml versus 474ml and 400ml (P=0.020).

CONCLUSIONS

Embolization decreases the risk of hemorrhage in highly vascularized metastases such as renal cell carcinoma. A benefit of embolization was not found for metastases of breast or pulmonary tumors. As far as other metastases, thyroid carcinoma should be analyzed on a greater cohort. The extent of surgery remains an important risk factor for intraoperative bleeding. A preoperative angiogram should be carried out in all types of metastases prior to a thoracolumbar corpectomy or vertebrectomy to perform an embolization if the tumor is hypervascular.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Comparing patients with spinal cord infarction and cerebral infarction: clinical characteristics, and short-term outcome

Background:

To compare the clinical characteristics, and short-term outcome of spinal cord infarction and cerebral infarction.

Methods:

Risk factors, concomitant diseases, neurological deficits on admission, and short-term outcome were registered among 28 patients with spinal cord infarction and 1075 patients with cerebral infarction admitted to the Department of Neurology, Haukeland University Hospital, Bergen, Norway. Multivariate analyses were performed with location of stroke (cord or brain), neurological deficits on admission, and short-term outcome (both Barthel Index [BI] 1 week after symptom onset and discharge home or to other institution) as dependent variables.

Results:

Multivariate analysis showed that patients with spinal cord infarction were younger, more often female, and less afflicted by hypertension and cardiac disease than patients with cerebral infarction. Functional score (BI) was lower among patients with spinal cord infarctions 1 week after onset of symptoms (P < 0.001). Odds ratio for being discharged home was 5.5 for patients with spinal cord infarction compared to cerebral infarction after adjusting for BI scored 1 week after onset (P = 0.019).

Conclusion:

Patients with spinal cord infarction have a risk factor profile that differs significantly from that of patients with cerebral infarction, although there are some parallels to cerebral infarction caused by atherosclerosis. Patients with spinal cord infarction were more likely to be discharged home when adjusting for early functional level on multivariate analysis.