Diagnosis and Management of Thoracic Myelopathy.

Thoracic myelopathy can be a challenging condition to diagnose and treat. Successful outcomes depend on early recondition of the pathology and appropriate surgical referral in cases of progressive neurologic deterioration. The thoracic cord is tethered in kyphosis by the dentate ligaments and contains a tenuous blood supply. These conditions make the thoracic cord particularly susceptible to external compression and ischemic damage. Careful preoperative planning with specific attention to the location and source of thoracic stenosis is critical to successful decompression and complication avoidance. The purpose of this discussion is to outline the common sources of thoracic myelopathy and current recommendations regarding diagnosis and management. The review concludes with an overview of the most up-to-date literature regarding clinical outcomes.

A Matched-Cohort Analysis of Outcomes in Patients with Hereditary Hemochromatosis After Anterior Cervical Discectomy and Fusion.

BACKGROUND: Hereditary hemochromatosis (HH) is a common autosomal recessive disorder. This disease affects gut iron transport, leading to iron overload, which affects immune function, coagulation mechanics, and bone health. Within the spine, HH contributes to decreased bone mineral density and accelerated intervertebral disc degeneration. The purpose of this study was to discover the differences in the rates of common 90-day postoperative complications and 1-year and 2-year surgical outcomes in patients with and without HH after anterior cervical discectomy and fusion (ACDF). METHODS: Using the PearlDiver database, patients with active diagnoses of HH before ACDF were matched to patients without HH using a 1:5 ratio on the basis of age, sex, body mass index, and comorbidities. Postoperative complications were assessed at 90 days, and 1-year and 2-year surgical outcomes were assessed. All outcomes and complications were analyzed using multivariate logistic regression with significance achieved at P < 0.05. RESULTS: Patients with HH had significantly higher rates of 1-year and 2-year reoperation rates compared with patients without HH (29.19% vs. 3.94% and 37.1% vs. 5.93%, respectively; P < 0.001). The rates of 90-day postoperative complications significantly increased in patients with HH including dysphagia, pneumonia, cerebrovascular accident, deep vein thrombosis, acute kidney injury, urinary tract infection, hyponatremia, surgical site infection, iatrogenic deformity, emergency department visit, and hospital readmission. CONCLUSIONS: Patients with HH undergoing ACDF showed increased 90-day postoperative complications and significantly increased rates of 1-year and 2-year reoperation compared with patients without HH. These findings suggest that iron overload may contribute to adverse outcomes in patients with HH undergoing 1-level and 2-level ACDF.

Carbon fiber lumbopelvic reconstruction following sacral giant cell tumor resection: illustrative case.

BACKGROUND: The use of carbon fiber or polyetheretherketone spine constructs has proven to be a safe and effective alternative to standard metal alloy. The mechanical properties of carbon fiber while unique provide a construct that is comparable in strength to previous titanium-based constructs and have additionally shown greater fatigue resistance. These constructs have been especially useful for the mechanical stabilization of the spine following tumor resection. The subsequent interference seen when imaging a patient with a traditional metallic construct is reduced and allows for improved tumor surveillance after the procedure, and a more accurate delivery of radiotherapy when indicated. OBSERVATIONS: This case report details the treatment of a 25-year-old female diagnosed with a sacral giant cell tumor. The authors discuss the use of a carbon fiber-reinforced polyetheretherketone for lumbopelvic reconstruction. LESSONS: Carbon fiber-reinforced polyetheretherketone with its radiolucency and rigidity is a reliable option for complex spinal reconstruction after tumor resection.

Impaction grafting of lumbar pedicle defects: a biomechanical study of a novel technique for pedicle screw revision.

OBJECTIVE: The two most common revision options available for the management of loose pedicle screws are larger-diameter screws and cement augmentation into the vertebral body for secondary fixation. An alternative revision method is impaction grafting (pedicoplasty) of the failed pedicle screw track. This technique uses the impaction of corticocancellous bone into the pedicle and vertebral body through a series of custom funnels to reconstitute a new pedicle wall and a neomedullary canal. The goal of this study was to compare the biomechanics of screws inserted after pedicoplasty (impaction grafting) of a pedicle defect to those of an upsized screw and a cement-augmented screw. METHODS: For this biomechanical cadaveric study the investigators used 10 vertebral bodies (L1-5) that were free of metastatic disease or primary bone disease. Following initial screw insertion, each screw was subjected to a pullout force that was applied axially along the screw trajectory at 5 mm per minute until failure. Each specimen was instrumented with a pedicoplasty revision using the original screw diameter, and on the contralateral side either a fenestrated screw with cement augmentation or a screw upsized by 1 mm was inserted in a randomized fashion. These revisions were then pulled out using the previously mentioned methods. RESULTS: Initial screw pullout values for the paired upsized screw and pedicoplasty were 717 ± 511 N and 774 ± 414 N, respectively (p = 0.747) (n = 14). Revised pullout values for the paired upsized screw and pedicoplasty were 775 ± 461 N and 762 ± 320 N, respectively (p = 0.932). Initial pullout values for the paired cement augmentation and pedicoplasty were 792 ± 434 N and 880 ± 558 N, respectively (p = 0.649). Revised pullout values for the paired cement augmentation and pedicoplasty were 1159 ± 300 N and 687 ± 213 N, respectively (p < 0.001). CONCLUSIONS: Pedicle defects are difficult to manage. Reconstitution of the pedicle and creation of a neomedullary canal appears to be possible through the use of pedicoplasty. Biomechanically, screws that have been used in pedicoplasty have equivalent pullout strength to an upsized screw, and have greater insertional torques than those with the same diameter that have not been used in pedicoplasty, yet they are not superior to cement augmentation. This study suggests that although cement augmentation appears to have superior pullout force, the novel pedicoplasty technique offers promise as a viable biological revision option for the management of failed pedicle screws compared with the option of standard upsized screws in a cadaveric model. These findings will ultimately need to be further assessed in a clinical setting.

Outcomes Following Anterior Cervical Discectomy and Fusion in Patients With Ehlers-Danlos Syndrome.

STUDY DESIGN: Retrospective database analysis. OBJECTIVES: To study postoperative complication rates following anterior cervical discectomy and fusion (ACDF) in patients with Ehlers-Danlos syndrome (EDS) compared with patients without EDS. METHODS: The Mariner database was utilized to identify patients with EDS undergoing one or two level anterior cervical discectomy and fusion (ACDF). Postoperative short-term outcomes assessed included medical complications, readmissions, and ED-visits within 90 days of surgery. Additionally, surgical complications including wound complications, surgical site infection, one- and two-year anterior revision along with posterior revision, pseudarthrosis, and hardware failure within 2 years were assessed. Multivariate logistic regression was used to adjust for demographic variables, comorbidities and number of levels operated on. RESULTS: The present study identified 533 patients in the EDS group and 2634 patients in the matched control group. EDS patients undergoing ACDF are at an increased risk for 90-day major medical complications (OR 3.31; P < .001). EDS patients were also found to be associated with surgical complications including wound complications (OR 2.94; P < .001), surgical site infection (OR 8.60; P < .001) within 90 days, pseudarthrosis (OR 2.33; P < .001), instrument failure (OR 4.03; P < .001), anterior revision (OR 22.87; P < .001), and posterior revision (OR 3.17; P < .001) within 2 years. CONCLUSIONS: EDS is associated with higher rates of both medical and surgical complications following ACDF. Spine surgeons should be cognizant of the increased risks in this population to provide appropriate preoperative counseling and enhanced perioperative medical management.

The Feasibility of Translaminar Screws in the Subaxial Cervical Spine: Computed Tomography and Cadaveric Validation.

BACKGROUND: The use of translaminar screws may serve as a viable salvage method for complicated cases. To our understanding, the study of the feasibility of translaminar screw insertion in the actual entire subaxial cervical spine has not been carried out yet. The purpose of this study was to report the feasibility of translaminar screw insertion in the entire subaxial cervical spine. METHODS: Eighteen cadaveric spines were harvested from C3 to C7 and 1-mm computed tomography (CT) scans and three-dimensional reconstructions were created to exclude any bony anomaly. Thirty anatomically intact segments were collected (C3, 2; C4, 3; C5, 3; C6, 8; and C7, 14), and randomly arranged. Twenty-one segments were physically separated at each vertebral level (group S), while 9 segments were not separated from the vertebral column and left in situ (group N-S). CT measurement of lamina thickness was done for both group S and group N-S, and manual measurement of various length and angle was done for group S only. Using the trajectory proposed by the previous studies, translaminar screws were placed at each level. Screw diameter was the same or 0.5 mm larger than the proposed diameter based on CT measurement. Post-insertion CT was performed. Cortical breakage was checked either visually or by CT. RESULTS: When 1° and 2° screws of the same size were used, medial cortex breakage was found 13% and 33% of the time, respectively. C7 was relatively safer than the other levels. With larger-sized screws, medial cortex breakage was found in 47% and 46% of 1° and 2° screws, respectively. There were no facet injuries due to the screws in group N-S. CONCLUSIONS: Translaminar screw insertion in the subaxial cervical spine is feasible only when the lamina is thick enough to avoid any breakage that could lead to further complications. The authors do not recommend inserting translaminar screws in the subaxial cervical spine except in some salvage cases in the presence of a thick lamina.

Integrated Custom Composite Polyetheretherketone/Carbon fiber (PEEK/CF) Vertebral Body Replacement (VBR) in the Treatment of Bone Tumors of the Spine: A Preliminary Report From a Multicenter Study.

STUDY DESIGN: Retrospective, multicenter chart, and radiologic review. OBJECTIVE: To present the first case series of bone tumors of the spine surgically reconstructed with a new custom, fully radiolucent, polyetheretherketone/carbon fiber (PEEK/CF) vertebral body replacement (VBR) integrated system. SUMMARY OF BACKGROUND DATA: Surgical resections of spinal tumors result in large defects and local recurrence remains a concern. Current titanium-based implants adversely affects postoperative imaging, directly affects ability to identify tumor recurrence, and for delivery of radiotherapy treatments. PEEK/CF spinal implants allows for improved tumor surveillance, precise pre-radiation Computed Tomography planning, and reduces interference with post-reconstructive adjuvant radiotherapy. METHOD: Thirteen patients with spinal tumors underwent vertebral body resection and reconstruction with an integrated, fully radiolucent, custom PEEK/CF vertebral body replacement, and radiolucent posterior PEEK/CF screw-rod system and/or radiolucent anterior PEEK/CF plate system. Clinical and radiographic data were tabulated. Need for adjuvant radiotherapy determined based on final tissue histology and extent of surgical margins. Postoperative surveillance imaging were reviewed for local tumor recurrence. RESULTS: The ability to integrate the PEEK/CF VBR connected to either the posterior screw-rod system, or anterior plate system provided immediate stability. The VBR was placed directly on cancellous vertebral body surface in 46.2% of cases. Loosening of the distal, or proximal, aspect of posterior system was seen in 15.4% of cases. There was no clinical or radiographic evidence of VBR migration and subsidence at latest follow up. Local recurrence occurred in one (7.7%) patient. CONCLUSION: This is the first series to describe the use of a fully-radiolucent, integrated, PEEK/CF implant system for spinal tumor reconstruction. The use of a PEEK/CF VBR system integrated to either the anterior plate, or posterior screw-rod system is feasible and allows for superior postoperative surveillance imaging and effective delivery of postoperative adjuvant radiotherapy.Level of Evidence: 4.

Use of the dual construct lowers rod strains in flexion-extension and lateral bending compared to two-rod and two-rod satellite constructs in a cadaveric spine corpectomy model.

BACKGROUND CONTEXT: Complex spinal reconstructions involving corpectomies, or osteotomies, place spinal implants at extremely high stresses that can lead to pseudoarthrosis and ultimately to rod failure, resulting in revision surgery. Current clinical options to increase the biomechanical strength of a construct include increasing rod diameter, changing rod material, or placing an additional satellite/outrigger rod on a standard two rod construct. Fundamentally, all of these constructs still rely on two longitudinal rods across the reconstruction site and are therefore at risk for rod fracture and loss of alignment. Initially described in 2006, the Dual Construct was developed to address this limitation by utilizing four distinct mechanically independent rods, which allowed for the creation of two separate, and distinct, constructs within each patient. Although there is early clinical evidence to support its efficacy, this is the first biomechanical study to compare the Dual Construct to the two-rod and two-rod with satellite configurations in a cadaveric study. PURPOSE: To assess the biomechanical impact of the Dual Construct technique to traditional two-rod and two-rod with satellite rod construct in a cadaveric model. STUDY DESIGN/SETTING: Biomechanical cadaveric study METHODS: Nine fresh-frozen human cadaveric spines (6 males, 3 females, 56 year +/- 9 years) from T9-pelvis were instrumented and tested utilizing all three configurations including two-rod construct, two-rod with satellite construct, and the Dual Construct technique. Biomechanical testing order of the various constructs was randomized to reduce potential effects of order bias. Strain gauges were placed in both the coronal and sagittal planes of the rods to track the strains during flexion-extension and lateral bending while undergoing range of motion testing. Testing was performed using pure-moment flexibility testing protocols. RESULTS: In flexion-extension, the resultant strain in the two-rod construct was an average 600±228 microstrain, the two-rod with satellite rod strain averaged 603±237 microstrain, and the Dual Construct averaged 403±149 microstrain. In lateral bending, the resultant strain in the two-rod construct was an average of 266±134 microstrain, the satellite rod strain was an average of 310±158 microstrain, and the Dual Construct averaged 118±51 microstrain. In both flexion extension and lateral bending, a significant reduction in strain was observed between the Dual Construct condition compared to both the two-rod and satellite configurations. No significant difference was found between the two-rod and two-rod with satellite rod configurations. CONCLUSIONS: The increase in load sharing significantly decreases the strain experienced across the Dual Construct compared to traditional two-rod and two-rod with satellite constructs. Global rod strains on primary rods cannot be reduced by simply increasing the number of satellite rods, but can only be reduce by increasing the actual number of primary rods.

Molecular Detection and Assessment of Intervertebral Disc Degeneration via a Collagen Hybridizing Peptide.

During aging, wear, and tear of intervertebral discs, human discs undergo a series of morphological and biochemical changes. Degradation of extracellular matrix proteins, e.g., collagen, arises as an important contributor and accelerator in this process. Existing methods to detect collagen degradation at the tissue level include histology and immunohistochemistry. Unfortunately, most of these methods only depict overall collagen content without the ability to specifically discern degraded collagen and to assess the severity of degeneration. To fill this technological gap, we developed a robust and simple approach to detect and assess early disc degeneration with a collagen hybridizing peptide (CHP) that hybridizes with the flawed triple helix structure in degraded collagen. Intriguingly, the CHP signal in mouse lumbar discs exhibited a linear incremental pattern with age. This finding was corroborated with histological analysis based on established methods. When comparing this analysis, a positive linear correlation was found between CHP fluorescence intensity and the histological score with a regression value of r 2 = 0.9478. In degenerative mouse discs elicited by pro-inflammatory stimuli (IL-1ß and LPS) ex vivo, the newly developed approach empowered prediction of the severity of disc degeneration. We further demonstrated higher CHP signals in a degenerative human disc tissue when compared to a normal sample. These findings also resonated with histological analysis. This approach lays a solid foundation for specific detection and assessment of intervertebral disc degeneration at the molecular level and will promote development of future disc regeneration strategies.

Recent Preoperative Lumbar Epidural Steroid Injection Is an Independent Risk Factor for Incidental Durotomy During Lumbar Discectomy.

STUDY DESIGN: Retrospective review. OBJECTIVE: To investigate the association between lumbar epidural steroid injection (LESI) and incidental durotomy (ID) in patients with a diagnosis of disc herniation undergoing a primary discectomy. METHODS: A Medicare patient database was queried for patients between the ages of 65 and 85 years who underwent a primary lumbar discectomy for a diagnosis of lumbar disc herniation or degeneration from 2008 to 2014. Our main cohort of 64 849 patients was then divided into 2 groups: patients who experienced a dural tear (N = 2369) and our matched (age, gender, and history of diabetes) control cohort of patients who did not (N = 62 480). All patients who had a history of LESI were further identified and stratified into 4 subgroups by duration between LESI and discectomy (<3 months, 3-6 months, 6 months to 1 year, and overall), and a comparison of the relative incidence of ID was made among these subgroups. A multivariate logistic regression analysis was employed to determine the relationship between LESI and ID. RESULTS: Overall incidence of ID was 3.7%. There was a significant difference in incidence of LESI (27.1% vs 35.0%, P < .001) between our control and ID groups. An adjusted odds ratio (OR) showed that prior LESI within 3 to 6 months (OR 1.47, 95% CI 1.20-1.81, P < .001) and within less than 3 months (OR 1.46, 95% CI 1.24-1.72, P < .001) of surgery were significantly associated with ID. CONCLUSION: LESI increases the risk of ID in patients who undergo a subsequent lumbar discectomy within 6 months of injection.

A New Formyl Peptide Receptor-1 Antagonist Conjugated Fullerene Nanoparticle for Targeted Treatment of Degenerative Disc Diseases.

Intervertebral disc degeneration associated back pain is the most common cause of disability worldwide; however, no safe and effective treatments have been available. Here, we report a new functionalized nanofullerene conjugated with a peptide that binds specifically to a formyl peptide receptor-1 (FPR-1) expressed on activated macrophages. The new nanoparticle (aka FT-C60) was synthesized by conjugating carboxyl-C60 with the primary amine group of the peptide with a fluorescence dye for easy detection. The new nanoparticle was characterized by X-ray photoelectron spectroscopy, mass spectroscopy, and gel electrophoresis. It possessed effective radical (hydroxyl and superoxide anions) scavenging capabilities in electron paramagnetic resonance spectroscopy. In cultured cells, the nanoparticle FT-C60 demonstrated preferential binding to FPR-1 on activated macrophages and significantly attenuated mRNA expressions of proinflammatory factors including interleukin-6, interleukin-1, tumor necrosis factor-alpha, and cyclooxygenase-2. In vivo animal studies exhibited that a single intravenous injection of FT-C60 effectively alleviated pain in an established mouse model of radiculopathy for up to post-operation day (POD) 12. Ex vivo near-infrared fluorescence imaging of the mouse spine confirmed the targeting property of FT-C60 toward the injured disc on POD 14. Quantitative analysis of histological staining on spine sections showed that nanoparticle FT-C60 dramatically reduced inflammation at the local injury site compared to injury only on POD 7. In summary, we developed a novel targeted nanoparticle for treatment of lumbar radiculopathy by systemic delivery. This is a first-of-its-kind study for developing a novel class of targeted and systemic nanoparticle therapeutics to treat degenerative disc diseases.

Risk of Surgical Site Infection and Mortality Following Lumbar Fusion Surgery in Patients With Chronic Steroid Usage and Chronic Methicillin-Resistant Staphylococcus aureus Infection.

STUDY DESIGN: A retrospective database analysis among Medicare beneficiaries OBJECTIVE.: The aim of this study was to determine the effect of chronic steroid use and chronic methicillin-resistant Staphylococcus aureus (MRSA) infection on rates of surgical site infection (SSI) and mortality in patients 65 years of age and older who were treated with lumbar spine fusion. SUMMARY OF BACKGROUND DATA: Systemic immunosuppression and infection focus elsewhere in the body are considered risk factors for SSI. Chronic steroid use and previous MRSA infection have been associated with an increased risk of SSI in some surgical procedures, but their impact on the risk of infection and mortality after lumbar fusion surgery has not been studied in detail. METHODS: The PearlDiver insurance-based database (2005-2012) was queried to identify 360,005 patients over 65 years of age who had undergone lumbar spine fusion. Of these patients, those who had been taking oral glucocorticoids chronically and those with a history of chronic MRSA infection were identified. The rates of SSI and mortality in these two cohorts were compared with an age- and risk-factor matched control cohort and odds ratio (OR) was calculated. RESULTS: Chronic oral steroid use was associated with a significantly increased risk of 1-year mortality [OR = 2.06, 95% confidence interval (95% CI) 1.13-3.78, P = 0.018] and significantly increased risk of SSI at 90 days (OR = 1.74, 95% CI 1.33-1.92, P < 0.001) and 1 year (OR = 1.88, 95% CI 1.41-2.01, P < 0.001). Chronic MRSA infection was associated with a significantly increased risk of SSI at 90 days (OR = 6.99, 95% CI 5.61-9.91, P < 0.001) and 1 year (OR = 24.0, 95%CI 22.20-28.46, P < 0.001) but did not significantly impact mortality. CONCLUSION: Patients over 65 years of age who are on chronic oral steroids or have a history of chronic MRSA infection are at a significantly increased risk of SSI following lumbar spine fusion. LEVEL OF EVIDENCE: 3.

Unplanned Immediate Return to Operating Room After Spine Surgery: Significance of Immediate Postoperative Radiographs.

STUDY DESIGN: Retrospective analysis; single center data. OBJECTIVE: The purpose of this study is to look at the utility and relevance of immediate postoperative radiographs in providing vital information leading to immediate revision after spine surgery. SUMMARY OF BACKGROUND DATA: Immediate postoperative radiographs are routinely obtained in the recovery room after spine surgery to verify the level, alignment of the spine, implant position, and the adequacy of the procedure. However, with the ability to utilize intraoperative fluoroscopy imaging for the same purpose, the requirement for immediate postoperative radiographs needs to be validated. The purpose of this study is to look at the utility and relevance of these postoperative radiographs in providing critical information that may warrant immediate intervention. METHODS: Retrospective analysis of all spine surgeries (elective and emergent), performed at a single center from 2011 to 2016, was done and cases returning to operating room within 48 hours were identified. Indication of immediate revision was reviewed and utility of immediate postoperative radiographs in guiding immediate revision was analyzed. RESULTS: A total of 1804 elective and urgent spinal surgeries were performed by seven surgeons. Twenty-two patients returned to operating room within 48 hours of their index procedures. Of these 22 cases, only two patients were noted to have positive findings on recovery room radiographs. The findings of suboptimal spinal alignment or failed instrumentation led to the immediate revision in both cases. Both cases involved instrumentation at cervicothoracic region and intraoperative imaging provided only limited visualization. CONCLUSION: Routine recovery room radiographs played a role in the decision to emergently return to the operating room in 0.10% (2/1804) cases at our institution. The potential benefit of immediate recovery room radiographs after spine surgery should be weighed against the added healthcare cost and patient discomfort associated with obtaining these radiographs routinely. Imaging may be delayed to a more elective time without any significant risk in majority of spine cases. LEVEL OF EVIDENCE: 3.

Fragility Fracture Risk in Elderly Patients With Cervical Myelopathy.

STUDY DESIGN: Retrospective review. OBJECTIVE: To identify and compare the incidences of fragility fractures amongst three elderly populations: the general population, patients with surgically treated cervical spondylotic myelopathy (CSM), and patients with CSM not surgically treated. SUMMARY OF BACKGROUND DATA: CSM is a common disease in the elderly. Progression of myelopathic symptoms, including gait imbalance, can be a source of morbidity as it can lead to increased falls. METHODS: Records of elderly patients with Medicare insurance from 2005 to 2014 were retrospectively reviewed. Three mutually exclusive populations of patients were identified for analysis, including a cohort of patients with a diagnosis of CSM who were not treated with surgery; a cohort of patients with CSM who were treated with surgery; and a group of control patients who had never been treated with cervical spine surgery nor were diagnosed with CSM. Incidence of fractures of the distal radius, proximal humerus, proximal femur, and lumbar spine were assessed and compared between cohorts, adjusted by age, sex, osteoporosis, dementia, cerebrovascular disease, and Charlson Comorbidity Index. RESULTS: A total of 891,864 patients were identified, of which 60,332 had a diagnosis of CSM and 24,439 underwent cervical spine surgery. Compared to general population controls, the 12-month adjusted odds of experiencing at least one fragility fracture were 1.59 times higher in patients with CSM who were not treated with surgery (P < 0.001). The analogous odds ratio was 1.34 (P < 0.001) at 3 years. Compared to nonsurgically treated patients with CSM, the odds of experiencing at least one fragility fracture were reduced to 0.89 in surgically treated patients (P = 0.008). CONCLUSION: Fragility fractures are a significant source of morbidity and mortality in elderly patients. CSM is associated with increased rates of fragility fractures, although surgical management of CSM may be protective against risk of fragility fracture. LEVEL OF EVIDENCE: 3.

Spinal Hematomas: What a Radiologist Needs to Know.

Spinal hematomas are a frequent indication for radiologic evaluation and can be a diagnostic dilemma for many radiologists and surgeons. There are four types of spinal hematomas: epidural, subdural, subarachnoid, and intramedullary (spinal cord) hematomas. Because they differ by their location in relationship to the meningeal membranes and spinal cord, unique radiologic appearances can be recognized to distinguish these types of spinal hemorrhage. Anatomic knowledge of the spinal compartments is essential to the radiologist for confident imaging diagnosis of spinal hematomas and to specify correct locations. MRI is the modality of choice to diagnose the location of the hematoma, characterize important features such as age of the hemorrhage, and detect associated injury or disease. Each type of spinal hematoma has imaging patterns and characteristics that distinguish it from the others, as these specific spinal compartments displace and affect the adjacent anatomic structures. Early detection and accurate localization of spinal hematomas is critical for the surgeon to address the proper treatment and surgical decompression, when necessary, as neurologic deficits may otherwise become permanent. Online supplemental material is available for this article. ©RSNA, 2018.

Safe zone for irrigation and debridement of psoas abscess through a dorsal spinal approach.

PURPOSE: This cadaver study was initiated to identify safe zones for psoas abscess debridement using a dorsal spinal approach. METHODS: Twenty total specimens were dissected and lumbar transverse process (TP) and psoas muscles were identified. The distance from the lateral psoas muscle to the transverse process tip was measured. The lumbar plexus was dissected from the psoas and the distance from the TP to the lateral border of the lumbar plexus was measured. The area between the lateral edge of the psoas and lumbar plexus at each lumbar level was considered a safe zone of approach for entry into the psoas muscle for abscess debridement. RESULTS: The most lateral portion of the lumbar plexus was 9.3 mm medial to the superior tip of the L1 TP and 9.2 mm medial to the inferior tip at L1, it was 11.8 and 11.7 mm medial at L2, 10.5 and 9.8 mm medial at L3, 6.6 and 6.2 mm medial at L4, and 1.0 and 0.9 mm medial at L5. The distances from the TP tip to the lateral edge of the psoas muscle were 5.7 and 5.5 mm medial to the superior and inferior tip of the TP at L1, 5.1 and 4.7 mm medial at L2, 2.5 and 1.8 mm medial at L3, 0.4 and 0 mm medial at L4 and 3.7 and 3.8 mm lateral at L5. CONCLUSIONS: This study provides landmarks to avoid the critical structures in the lumbar spine.

Posterior identification and exposure of the V3 segment of the vertebral artery.

OBJECTIVE: The purpose of this study was to define the anatomy of the V3 segment of the vertebral artery (VA) from the posterior approach. METHODS: Ten formalin-fixed cadavers were carefully dissected bilaterally using landmark features to identify and safely expose the VA from the posterior. Measurements regarding morphometric characteristics of landmark features and feasible resection quantifications were obtained and analyzed. The C2 pars was resected completely in all cadavers, averaging 15.03 ± 1.06 mm in thickness. RESULTS: The average diameter of the VA at the midline of C2 on the right side was 4.66 ± 0.51 mm compared to the left 5.2 ± 0.49 mm (P = 0.002). The distance of the VA from the midline increased from caudal to rostral. The distance between the VA to the lateral edge of the dura in the middle of the window of approach was 9.67 ± 0.81 mm. The rostral-caudal length of the window of approach was 21.94 ± 1.60 mm. The percentage of C2 body removal was 28.04% ± 6.09% through each side (249.55 ± 55.5/898.2 ± 146.17 mm2). While carefully exposing the VA, a posterior approach can be feasible in cases of injury during C1-C2 instrumentation or during resection of tumors of the C2 pars with or without extension into the C2 body. DISCUSSION: The posterior approach for a C2 partial corpectomy can also be used as an adjunct to anterior approaches when necessary to widen the extent of bone resection. CONCLUSION: Exposure of the V3 segment of the vertebral artery was defined as well as the extent of C2 corpectomy through the posterior approach.

Rheumatoid Arthritis Is Associated With an Increased Risk of Postoperative Infection and Revision Surgery in Elderly Patients Undergoing Anterior Cervical Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVE: To identify the incidence and analyze the risk of postoperative complications amongst elderly patients with rheumatoid arthritis undergoing anterior cervical fusion. SUMMARY OF BACKGROUND DATA: Previous studies have reported elevated risks of postoperative complications for patients with rheumatoid arthritis undergoing orthopedic procedures. However, little is known about the risk of postoperative complications in rheumatoid arthritis patients after spine surgery. METHODS: A commercially available database was queried for all Medicare patients 65 years of age and older undergoing one- or two-level primary anterior cervical fusion surgeries from 2005 to 2013. Complications, hospitalization costs, and length of stay were queried. Multivariate logistic regression analyses were performed to estimate the odds ratio for each complication adjusted for age, sex, and Charlson Comorbidity Index. RESULTS: A total of 6067 patients with a history of rheumatoid arthritis and 113,187 controls were identified. Significantly higher incidences of major medical complications (7.5% vs. 5.9%, P < 0.001), postoperative infections (2.6% vs. 1.5%, P < 0.001), and revision surgery (1.1% vs. 0.6%, P < 0.001) were observed amongst the rheumatoid arthritis cohort. Significantly greater average cost of hospitalization ($17,622 vs. $12,489, P < 0.001) and average length of stay (3.13 vs. 2.08 days, P < 0.001) were also observed. CONCLUSION: Patients with rheumatoid arthritis undergoing anterior cervical fusion face increased risks of postoperative infection and revision surgery compared to normal controls. This information is valuable for preoperative counseling and risk stratification. LEVEL OF EVIDENCE: 3.