Clinical Relationship of Degenerative Changes between the Cervical and Lumbar Spine.

STUDY DESIGN: Retrospective, observational, case series. PURPOSE: To elucidate the prevalence of degenerative changes in the cervical and lumbar spine and estimate the degenerative changes in the cervical spine based on the degeneration of lumbar disc through a retrospective review of magnetic resonance (MR) images. OVERVIEW OF LITERATURE: Over 50% of middle-aged adults show evidence of spinal degeneration. However, the relationship between degenerative changes in the cervical and lumbar spine has yet to be elucidated. METHODS: A retrospective review of positional MR images of 152 patients with symptoms related to cervical and lumbar spondylosis with or without a neurogenic component was conducted. The degree of intervertebral disc degeneration (IDD) was assessed on a grade of 1-5 for each segment of the cervical and lumbar spine using MR T2-weighted sagittal images. The grades across all segments were summed to produce the degenerative disc score (DDS) for the cervical and lumbar spine. The patients were divided into two groups based on the IDD grade for each lumbar segment: normal (grades 1 and 2) and degenerative (grades 3-5). RESULTS: DDSs for the cervical and lumbar spine were positively correlated. Significant differences in cervical DDSs between the groups were observed in all lumbar segments. Although there were no significant differences in cervical DDSs among the degenerative lumbar segment, cervical DDSs at the L1-2 and L2-3 segments tended to be higher than those at the L3-4, L4-5, and L5-S degenerative segments. CONCLUSIONS: Our study shows that participants with degenerative changes in the upper lumbar segments are more likely to have a certain amount of cervical spondylosis. This information could be used to lower the incidence of a missed diagnosis of cervical spine disorders in patients presenting with lumbar spine symptomology.

Sequential neurological improvements after conservative treatment in patients with complete motor paralysis caused by cervical spinal cord injury without bone and disc injury.

OBJECTIVE This study investigated neurological improvements after conservative treatment in patients with complete motor paralysis caused by acute cervical spinal cord injury (SCI) without bone and disc injury. METHODS This study was retrospective. The authors evaluated neurological outcomes after conservative treatment of 62 patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma. The sequential changes in their American Spinal Injury Association Impairment Scale (AIS) grades were reviewed at follow-up 24-72 hours, 1 week, and 1, 3, and 6 months after treatment. RESULTS Of the 31 patients with a baseline AIS grade of A, 2 (6.5%) patients improved to grade B, 5 (16.1%) improved to grade C, and 2 (6.5%) improved to grade D by the 6-month follow-up. The 22 (71.0%) patients who remained at AIS grade A 1 month after injury showed no neurological improvement at the 6-month follow-up. Of the 31 patients with a baseline AIS grade of B, 12 (38.7%) patients showed at least a 1-grade improvement at the 1-month follow-up; 11 (35.5%) patients improved to grade C and 16 (51.6%) patients improved to grade D at the 6-month follow-up. CONCLUSIONS Even in patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma, approximately 30% of the patients with an AIS grade of A and 85% of the patients with an AIS grade B improved neurologically after conservative treatment. It is very important to recognize the extent of neurological improvement possible with conservative treatment, even for severe complete motor paralysis.

Sensitivity and specificity of the 'knee-up test' for estimation of the American Spinal Injury Association Impairment Scale in patients with acute motor incomplete cervical spinal cord injury.

STUDY DESIGN: A retrospective study. OBJECTIVE: Precise classification of the neurological state of patients with acute cervical spinal cord injury (CSCI) can be challenging. This study proposed a useful and simple clinical method to help classify patients with incomplete CSCI. SETTING: Spinal Injuries Centre, Japan. METHODS: The sensitivity and specificity of the 'knee-up test' were evaluated in patients with acute CSCI classified as American Spinal Injury Association Impairment Scale (AIS) C or D. The result is positive if the patient can lift the knee in one or both legs to an upright position, whereas the result is negative if the patient is unable to lift the knee in either leg to an upright position. The AIS of these patients was classified according to a strict computerised algorithm designed by Walden et al., and the knee-up test was tested by non-expert examiners. RESULTS: Among the 200 patients, 95 and 105 were classified as AIS C and AIS D, respectively. Overall, 126 and 74 patients demonstrated positive and negative results, respectively, when evaluated using the knee-up test. A total of 104 patients with positive results and 73 patients with negative results were classified as AIS D and AIS C, respectively. The sensitivity, specificity, positive predictive and negative predictive values of this test for all patients were 99.1, 76.8, 82.5 and 98.7, respectively. CONCLUSIONS: The knee-up test may allow easy and highly accurate estimation, without the need for special skills, of AIS classification for patients with incomplete CSCI.

A Safe Surgical Procedure for Old Distractive Flexion Injuries of the Subaxial Cervical Spine.

STUDY DESIGN: Retrospective review. PURPOSE: To describe a safe and effective surgical procedure for old distractive flexion (DF) injuries of the subaxial cervical spine. OVERVIEW OF LITERATURE: Surgical treatment is required in old cases when a progression of the kyphotic deformity and/or persistent neck pain and/or the appearance of new neurological symptoms are observed. Since surgical treatment is more complicated and dangerous in old cases than in acute distractive-flexion cases, the indications for surgery and the selection of the surgical procedure must be carefully conducted. METHODS: To identify a safe and effective surgical procedure, the procedure selected, reason(s) for its selection, and associated neurological complications were investigated in 13 patients with old cervical DF injuries. RESULTS: No neurological complications were observed in nine patients (DF stage 2 or 3) who underwent the anterior-posterior-anterior (A-P-A) method and two patients (DF stage 1) who underwent the posterior method. It was initially planned that two patients (DF stage 2) who underwent the P-A method would be treated using the Posterior method alone; however, anterior discectomy was added to the procedure after the development of a severe spinal cord disorder. CONCLUSIONS: The A-P-A method (anterior discectomy, posterior release and/or partial facetectomy, reduction and instrumentation, anterior bone grafting) is considered to be a suitable surgical procedure for old cervical DF injuries.

Macrophage Infiltration Is a Causative Factor for Ligamentum Flavum Hypertrophy through the Activation of Collagen Production in Fibroblasts.

Ligamentum flavum (LF) hypertrophy causes lumbar spinal canal stenosis, leading to leg pain and disability in activities of daily living in elderly individuals. Although previous studies have been performed on LF hypertrophy, its pathomechanisms have not been fully elucidated. In this study, we demonstrated that infiltrating macrophages were a causative factor for LF hypertrophy. Induction of macrophages into the mouse LF by applying a microinjury resulted in LF hypertrophy along with collagen accumulation and fibroblasts proliferation at the injured site, which were very similar to the characteristics observed in the severely hypertrophied LF of human. However, we found that macrophage depletion by injecting clodronate-containing liposomes counteracted LF hypertrophy even with microinjury. For identification of fibroblasts in the LF, we used collagen type I α2 linked to green fluorescent protein transgenic mice and selectively isolated green fluorescent protein-positive fibroblasts from the microinjured LF using laser microdissection. A quantitative RT-PCR on laser microdissection samples revealed that the gene expression of collagen markedly increased in the fibroblasts at the injured site with infiltrating macrophages compared with the uninjured location. These results suggested that macrophage infiltration was crucial for LF hypertrophy by stimulating collagen production in fibroblasts, providing better understanding of the pathophysiology of LF hypertrophy.

Can the acute magnetic resonance imaging features reflect neurologic prognosis in patients with cervical spinal cord injury?

BACKGROUND CONTEXT: Several prognostic studies looked for an association between the degree of spinal cord injury (SCI), as depicted by primary magnetic resonance imaging (MRI) within 72 hours of injury, and neurologic outcome. It was not clearly demonstrated whether the MRI at any time correlates with neurologic prognosis. PURPOSE: The purpose of the present study was to investigate the relationship between acute MRI features and neurologic prognosis, especially walking ability of patients with cervical spinal cord injury (CSCI). Moreover, at any point, MRI was clearly correlated with the patient's prognosis. STUDY DESIGN: Retrospective image study. PATIENT SAMPLE: From January 2010 to October 2015, 102 patients with CSCI were treated in our hospital. Patients who were admitted to our hospital within 3 days after injury were included in this study. The diagnosis was 78 patients for CSCI with no or minor bony injury and 24 patients for CSCI with fracture or dislocation. A total of 88 men and 14 women were recruited, and the mean patient age was 62.6 years (range, 16-86 years). Paralysis at the time of admission was graded as A in 32, B in 15, C in 42, and D in 13 patients on the basis of the American Spinal Injury Association (ASIA) impairment scale. Patients with CSCI with fracture or dislocation were treated with fixation surgery and those with CSCI with no or minor bony injury were treated conservatively. Patients were followed up for an average of 168 days (range, 25-496 days). OUTCOME MEASURES: Neurologic evaluation was performed using the ASIA motor score and the modified Frankel grade at the time of admission and discharge. METHODS: Magnetic resonance imaging was performed for all patients at admission. Using the MRI sagittal images, we measured the vertical diameter of intramedullary high-intensity changed area with T2-weighted images at the injured segment. We studied separately the patients divided into two groups: 0-1 day admission after injury, and 2-3 days admission after injury. We evaluated the relationship between the vertical diameter of T2 high-intensity changed area in MR images and neurologic outcome in these two groups. This study does not contain any conflict of interest. RESULTS: In the group admitted at 0-1 day after injury, there was a relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, but correlation coefficient was low (0.3766 at admission and 0.4239 at discharge). On the other hand, in the group admitted at 2-3 days after injury, there was a significant relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, and correlation coefficient was very high (0.6840 at admission and 0.5293 at discharge). In the group admitted at 2-3 days after injury, a total of 17 patients (68%) recovered to walk with or without a cane. Receiver operating characteristic (ROC) curve analysis demonstrated that the optimal vertical diameter of T2 high-intensity area cutoffvalue for patients who were able to walk at discharge was 45.8 mm. If the vertical diameter of T2 high-intensity area cutoff value was 45 mm, there was a significant positive correlation with being able to walk at discharge (p<.0001). CONCLUSIONS: From our study, 2-3 days after injury, a significant relationship was observed between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge. Zero to 1 day after injury, the relationship between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge was weak. Neurologic prognosis is more correlated with MRI after 2-3 days after the injury. If the vertical diameter of T2 high-intensity area was <45 mm, the patients were able to walk with or without a cane at discharge. T2 high-intensity changed area can reflect the neurologic prognosis in patients with CSCI.

Experimental Mouse Model of Lumbar Ligamentum Flavum Hypertrophy.

Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in elderly people, with the number of LSCS patients increasing due to the aging of the population. The ligamentum flavum (LF) is a spinal ligament located in the interior of the vertebral canal, and hypertrophy of the LF, which causes the direct compression of the nerve roots and/or cauda equine, is a major cause of LSCS. Although there have been previous studies on LF hypertrophy, its pathomechanism remains unclear. The purpose of this study is to establish a relevant mouse model of LF hypertrophy and to examine disease-related factors. First, we focused on mechanical stress and developed a loading device for applying consecutive mechanical flexion-extension stress to the mouse LF. After 12 weeks of mechanical stress loading, we found that the LF thickness in the stress group was significantly increased in comparison to the control group. In addition, there were significant increases in the area of collagen fibers, the number of LF cells, and the gene expression of several fibrosis-related factors. However, in this mecnanical stress model, there was no macrophage infiltration, angiogenesis, or increase in the expression of transforming growth factor-ß1 (TGF-ß1), which are characteristic features of LF hypertrophy in LSCS patients. We therefore examined the influence of infiltrating macrophages on LF hypertrophy. After inducing macrophage infiltration by micro-injury to the mouse LF, we found excessive collagen synthesis in the injured site with the increased TGF-ß1 expression at 2 weeks after injury, and further confirmed LF hypertrophy at 6 weeks after injury. Our findings demonstrate that mechanical stress is a causative factor for LF hypertrophy and strongly suggest the importance of macrophage infiltration in the progression of LF hypertrophy via the stimulation of collagen production.

Morphologic Evaluation of Lumbosacral Nerve Roots in the Vertebral Foramen: Measurement of Local Pressure of the Intervertebral Foramen.

STUDY DESIGN: The prospective cohort study. OBJECTIVE OF THE STUDY: The objective was to evaluate the relationships between local pressure changes of the intervertebral foramen during lumbar spine extension and lumbar foraminal morphology. SUMMARY OF BACKGROUND DATA: The physiological states of lumbosacral nerve roots in the vertebral foramen remain controversial. METHODS: We evaluated 56 lumbosacral vertebral foramens in 21 patients with L4-degenerative spondylolisthesis. All patients underwent L4-5 posterolateral fusion (PLF). The local pressure of the intervertebral foramen was measured intraoperatively, and measurement was performed before and after L4-5 PLF. We defined the changes in the ratio of local pressure between lumbar flexion to extension as percent pressure. The sagittal angular motion, distance between the inferior cortex of the cranial pedicle and superior cortex of the caudal pedicle, posterosuperior margin of the superior vertebral body and superior articular facet, posteroinferior edge of the superior vertebral body and inferior articular facet, and the intervertebral disc height were measured using preoperative functional plain radiographs and CT images. RESULTS: The average local pressure of the intervertebral foramen significantly increased during lumbar extension. However, the L4-5 vertebral foraminal pressure after PLF were nearly identical. There was no significant correlation between percent pressure and lumbar range of motion. Furthermore, there were no significant correlations between percent pressure and each morphologic parameter of the lumbar foramen. CONCLUSIONS: There were no significant relationships between the lumbar foraminal morphology and intervertebral foraminal pressure changes during lumbar extension, and L4-5 vertebral foraminal pressure was not affected by the lumbar posture after L4-5 posterior fusion. On the basis of the results, the external dynamic stresses on the nerve roots in the vertebral foramen might be improved by lumbar posterior fusion using instrumentation without direct decompression of the vertebral foramen.

Kinematic Effects of Cervical Laminoplasty for Cervical Spondylotic Myelopathy on the Occipitoatlantoaxial Junction.

STUDY DESIGN: A retrospective evaluation of sagittal angular motion from cervical spinal flexion to extension. OBJECTIVE: To evaluate the kinematic effects of cervical laminoplasty for cervical spondylotic myelopathy (CSM) on the occipitoatlantoaxial junction. SUMMARY OF BACKGROUND DATA: The kinematic effects of cervical laminoplasty for CSM on the occipitoatlantoaxial junction remain controversial. METHODS: A total of 65 CSM patients who were treated with cervical laminoplasty ranging from the C3 to C7 vertebrae were included in the study. After surgery, all patients wore a Philadelphia collar for the first week and began cervical range of motion exercises as soon as possible. Functional plain radiographs were obtained preoperatively and at 1 and 3 years postoperatively. Sagittal angular motion from cervical spinal flexion to extension was measured using the Cobb technique at 7 cervical segments (Oc-C1, C1-C2, C2-C3, C3-C4, C4-C5, C5-C6, and C6-C7). We defined the contribution of each segment's mobility to the total angular mobility of the cervical spine as percent segmental mobility. RESULTS: Total cervical angular mobility significantly decreased after cervical laminoplasty. There were no significant differences in Oc-C2 angular mobility; however, C2-C7 angular mobility had significantly decreased by 3 years postoperatively. No significant differences in percent segmental mobility were observed at 1 year postoperatively except at the C3-C4 segment. By 3 years postoperatively, percent mobility at the Oc-C1 and C1-C2 segments had significantly increased, whereas that at the C3-C4 and C5-C6 segments had significantly decreased. CONCLUSIONS: Our results suggest that, although the contribution of occipitoatlantoaxial junctional mobility to total cervical mobility increases, dynamic mechanical stress to the occipitoatlantoaxial junction does not increase following laminoplasty, and no adjacent segmental disorder at the occipitoatlantoaxial junction was observed within 3 years postoperatively. We hypothesized that early removal of the cervical collar and early cervical range of motion exercises may contribute to these kinematic changes.

"Knee-up test" for easy detection of postoperative motor deficits following spinal surgery.

BACKGROUND CONTEXT: Neurologic motor deficit is a serious complication of spinal surgery. Early diagnosis of complications by neurologic examination immediately after spinal surgery is mandatory. However, patients cannot always cooperate with the physician in the very early stages of recovery. PURPOSE: The aim of the present study is to prospectively investigate the usefulness of the "knee-up test" for easy detection of postoperative motor deficits. STUDY DESIGN: A prospective clinical study was carried out. PATIENT SAMPLE: Patients with spinal disorder operated upon at a single institute were administered the knee-up test after an anesthesiologist had judged that endotracheal extubation was possible. OUTCOME MEASURES: The outcome measures were preoperative and postoperative Manual Muscle Testing. METHODS: A simple yet reliable method known as the "knee-up test" was developed to easily assess postoperative deficits before endotracheal extubation. When the patient's knee is passively lifted up and the patient is able to maintain this position in both legs, the result is negative, whereas when the patient is unable to maintain the knee in an upright position for one or both legs, the result is positive. The presently accepted criterion for a new-onset postoperative neurologic motor deficit is motor weakness leading to a decrease in function of at least two grades in more than one muscle function within 12 hours of spinal surgery, as evaluated by the Manual Muscle Testing. The association between the presence of new-onset motor deficits and the results of the knee-up test was prospectively investigated. RESULTS: Seventeen patients exhibited positive results when evaluated using the knee-up test, whereas 521 patients exhibited negative results. Sixteen of the patients with positive results were determined to have new-onset motor deficits, whereas no new-onset motor deficits were observed in the remaining patient. Of the 521 patients with negative knee-up test results, only 2 were determined to have new-onset motor deficits, whereas no new-onset motor deficits were observed in the remaining 519 patients. The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9, 99.8, 94.1, and 99.6, respectively. CONCLUSIONS: The knee-up test may allow for early and easy detection of postoperative motor deficits with high probability in very early stages.

Clinical Influence of Cervical Spinal Canal Stenosis on Neurological Outcome after Traumatic Cervical Spinal Cord Injury without Major Fracture or Dislocation.

STUDY DESIGN: Retrospective case series. PURPOSE: To clarify the influence of cervical spinal canal stenosis (CSCS) on neurological functional recovery after traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation. OVERVIEW OF LITERATURE: The biomechanical etiology of traumatic CSCI remains under discussion and its relationship with CSCS is one of the most controversial issues in the clinical management of traumatic CSCI. METHODS: To obtain a relatively uniform background, patients non-surgically treated for an acute C3-4 level CSCI without major fracture or dislocation were selected. We analyzed 58 subjects with traumatic CSCI using T2-weighted mid-sagittal magnetic resonance imaging. The sagittal diameter of the cerebrospinal fluid (CSF) column, degree of canal stenosis, and neurologic outcomes in motor function, including improvement rate, were assessed. RESULTS: There were no significant relationships between sagittal diameter of the CSF column at the C3-4 segment and their American Spinal Injury Association motor scores at both admission and discharge. Moreover, no significant relationships were observed between the sagittal diameter of the CSF column at the C3-4 segment and their neurological recovery during the following period. CONCLUSIONS: No relationships between pre-existing CSCS and neurological outcomes were evident after traumatic CSCI. These results suggest that decompression surgery might not be recommended for traumatic CSCI without major fracture or dislocation despite pre-existing CSCS.

Morphology of the injured posterior wall causing spinal canal encroachment in osteoporotic vertebral fractures.

BACKGROUND CONTEXT: The relationship between fractured posterior vertebral wall patterns and the protrusion of bony fragments into the spinal canal is not clear. PURPOSE: We sought to elucidate the effects of fracture patterns of the injured posterior wall on posterior wall instability and spinal canal encroachment using computed tomography myelography (CTM) in two different positions. STUDY DESIGN/SETTING: This is a prospective analysis of CTM in both supine and semi-sitting positions. PATIENT SAMPLE: The sample includes 36 consecutive elderly patients with delayed neurologic disorders due to insufficient bone union at the posterior vertebral wall after vertebral fracture. OUTCOME MEASURES: Radiological parameters, including the rates of dural compression and of occupation by bony fragments (OBFr) and the posterior vertebral body height ratio (PVBHr), were used. METHODS: All patients were examined using CTM in both supine and semi-sitting positions. According to fracture patterns of the posterior vertebral wall, we classified injured posterior walls with one fragment as the simple type and those with two or more fragments as the comminuted type. RESULTS: The simple type was found in 19 of 36 cases, whereas the comminuted type was found in 17 of 36 cases. A significant correlation was identified between changes in OBFr and PVBHr in both the simple and comminuted types. The mean change of PVBHr between the two positions in the comminuted type was significantly larger (9.2%) than that in the simple type (4.8%). Likewise, the mean change in OBFr in the comminuted type (14.0%) was significantly larger than that in the simple type (8.2%), indicating that the injured posterior vertebral wall with the comminuted type would be more likely to collapse and protrude into the spinal canal. CONCLUSIONS: Both simple and comminuted fracture types could cause protrusion of vertebral fragments into the spinal canal because of a collapsing non-united posterior vertebral wall; however, the comminuted type showed more severe spinal canal encroachment, with axial loading. The morphology of the injured posterior wall is thus important for estimating instability.

A comparison of commercially available demineralized bone matrices with and without human mesenchymal stem cells in a rodent spinal fusion model.

OBJECTIVE The efficacy of some demineralized bone matrix (DBM) substances has been demonstrated in the spinal fusion of rats; however, no previous comparative study has reported the efficacy of DBM with human mesenchymal stem cells (hMSCs). There is an added cost to the products with stem cells, which should be justified by improved osteogenic potential. The purpose of this study is to prospectively compare the fusion rates of 3 different commercially available DBM substances, both with and without hMSCs. METHODS Posterolateral fusion was performed in 32 mature athymic nude rats. Three groups of 8 rats were implanted with 1 of 3 DBMs: Trinity Evolution (DBM with stem cells), Grafton (DBM without stem cells), or DBX (DBM without stem cells). A fourth group with no implanted material was used as a control group. Radiographs were obtained at 2, 4, and 8 weeks. The rats were euthanized at 8 weeks. Overall fusion was determined by manual palpation and micro-CT. RESULTS The fusion rates at 8 weeks on the radiographs for Trinity Evolution, Grafton, and DBX were 8 of 8 rats, 3 of 8 rats, and 5 of 8 rats, respectively. A significant difference was found between Trinity Evolution and Grafton (p = 0.01). The overall fusion rates as determined by micro-CT and manual palpation for Trinity Evolution, Grafton, and DBX were 4 of 8 rats, 3 of 8 rats, and 3 of 8 rats, respectively. The Trinity Evolution substance had the highest overall fusion rate, however no significant difference was found between groups. CONCLUSIONS The efficacies of these DBM substances are demonstrated; however, the advantage of DBM with hMSCs could not be found in terms of posterolateral fusion. When evaluating spinal fusion using DBM substances, CT analysis is necessary in order to not overestimate fusion.

A Study of Risk Factors for Tracheostomy in Patients With a Cervical Spinal Cord Injury.

STUDY DESIGN: A retrospective, consecutive case series. OBJECTIVE: To determine the risk factors for a tracheostomy in patients with a cervical spinal cord injury. SUMMARY AND BACKGROUND DATE: Respiratory status cannot be stabilized in patients with a cervical spinal cord injury (CSCI) for various reasons, so a number of these patients require long-term respiratory care and a tracheostomy. Various studies have described risk factors for a tracheostomy, but none have indicated a relationship between imaging assessment and the need for a tracheostomy. The current study used imaging assessment and other approaches to assess and examine the risk factors for a tracheostomy in patients with a CSCI. METHODS: Subjects were 199 patients who were treated at the Spinal Injuries Center within 72 hours of a CSCI over 8-year period. Risk factors for a tracheostomy were retrospectively studied. Patients were assessed in terms of 10 items: age, sex, the presence of a vertebral fracture or dislocation, ASIA Impairment Scale, the neurological level of injury (NLI), PaO2, PaCO2, the level of injury on magnetic resonance imaging (MRI), the presence of hematoma-like changes (a hypointense core surrounded by a hyperintense rim in T2-weighted images) on MRI, and the Injury Severity Score.Items were analyzed multivariate logistic regression, and P < 0.05 was considered to indicate a significant difference. RESULTS: Twenty-three of the 199 patients required a tracheostomy, accounting for 11.6% of patients with a CSCI. Univariate analyses of the risk factors for tracheostomy revealed significant differences for six items: age, Injury Severity Score, presence of fracture or dislocation, ASIA Impairment Scale A, NLI C4 or above, and MRI scans revealing hematoma-like changes. Multivariate logistic regression analyses revealed significant differences in terms of two items: NLI C4 or above and MRI scans revealing hematoma-like changes. Thirty patients had both an NLI C4 or above and MRI scans revealing hematoma-like changes. Of these, 17 (56.7%) required a tracheostomy. CONCLUSION: Patients with an NLI C4 or above and MRI scans revealing hematoma-like changes were likely to require a tracheostomy. An early tracheostomy should be considered for patients with both of these characteristics. LEVEL OF EVIDENCE: 3.

Risk factors for adjacent segment pathology requiring additional surgery after single-level spinal fusion: impact of pre-existing spinal stenosis demonstrated by preoperative myelography.

PURPOSE: We determined the incidence of and risk factors for clinical adjacent segment pathology (C-ASP) requiring additional surgeries among patients previously treated with one-segment lumbar decompression and fusion surgery. METHODS: We retrospectively analysed 161 consecutive patients who underwent one-segment lumbar decompression and fusion surgery for L4 degenerative spondylolisthesis. Patient age, sex, body mass index (BMI), facet orientation and tropism, laminar inclination angle, spinal canal stenosis ratio [on myelography and magnetic resonance imaging (MRI)], preoperative adjacent segment instability, arthrodesis type, pseudarthrosis, segmental lordosis at L4-5, and the present L4 slip were evaluated by a log-rank test using the Kaplan-Meier method. A multivariate Cox proportional-hazards model was used to analyse all factors found significant by the log-rank test. RESULTS: Of 161 patients, 22 patients (13.7 %) had additional surgeries at cranial segments located adjacent to the index surgery's location. Pre-existing canal stenosis ≥47 % at the adjacent segment on myelography, greater facet tropism, and high BMI were significant risk factors for C-ASP. The estimated incidences at 10 years postoperatively for each of these factors were 51.3, 39.6, and 32.5 %, and the risks for C-ASP were 4.9, 3.7, and, 3.1 times higher than their counterparts, respectively. Notably, spinal canal stenosis on myelography, but not on MRI, was found to be a significant risk factor for C-ASP (log-rank test P < 0.0001 and 0.299, respectively). CONCLUSIONS: Pre-existing spinal stenosis, greater facet tropism, and higher BMI significantly increased C-ASP risk. Myelography is a more accurate method for detecting latent spinal canal stenosis as a risk factor for C-ASP.

The Compensatory Relationship of Upper and Subaxial Cervical Motion in the Presence of Cervical Spondylosis.

STUDY DESIGN: This study was an in vivo kinematic magnetic resonance imaging analysis of cervical spinal motion in human subjects. OBJECTIVE: The objective of the study was to identify associations between disk degeneration in the subaxial cervical spine and upper cervical spinal motion in patients with general age-related cervical spondylosis. SUMMARY OF BACKGROUND DATA: The kinematic relationship between the occipital-atlantoaxial complex and subaxial cervical spine in patients with cervical spondylosis and decreased cervical motion is not well understood. METHODS: A total of 446 symptomatic patients who had neck pain with and without neurogenic symptoms were included in this study. Kinematic magnetic resonance imaging was performed with dynamic motion of the cervical spine in upright, weight-bearing neutral, flexion, and extension positions. Intervertebral disk degeneration for each segment from C2-3 to C7-T1 and sagittal angular motion between flexion and extension for each segment from Oc-C1 to C7-T1 was evaluated. Depending on the amount of sagittal subaxial angular motion, the patients were classified into 3 groups by sagittal angular motion using cutoff points based on tertile (<36-degree group: 149 cases; 36-47-degree group: 148 cases; and >47-degree group: 149 cases). RESULTS: A significant correlation was found between subaxial angular motion and intervertebral disk degeneration, indicating that the subaxial motion decreases according to the degree of disk degeneration. Mean angular motion of the occipital-atlantoaxial complex, especially of Oc-C1, was significantly higher in the <36-degree and 36-47-degree group than in the >47-degree group, whereas no significant difference was found at C1-C2. CONCLUSIONS: Our study demonstrates that decreased subaxial cervical spinal motion is associated with intervertebral disk degeneration in a symptomatic population. This decrease in mobility at the subaxial cervical spine is compensated for by an increase in angular mobility of the upper cervical spine at the occipital-atlantoaxial complex, especially at Oc-C1.

D-dimer screening for deep venous thrombosis in traumatic cervical spinal injuries.

BACKGROUND CONTEXT: Deep venous thrombosis (DVT) in spinal cord injury (SCI) patients is a life-threatening comorbidity. Despite its seriousness, prophylaxis and screening for DVT in SCI patients are still not sophisticated. PURPOSE: This study aimed to define the epidemiology and incidence of DVT in acute traumatic cervical SCI in a Japanese population, determine the best timing for DVT screening, and determine the optimal D-dimer threshold level for use as an easy and minimally invasive screening tool. STUDY DESIGN: This is a prospective clinical study. PATIENT SAMPLE: The patient sample included acute traumatic cervical SCI patients who were admitted to our facility within 2 weeks after injury. OUTCOME MEASURE: Multivariate logistic regression was performed for outcome measure. METHODS: We enrolled 268 patients (223 men and 45 women), from April 2007 to December 2012. After excluding early drop-out patients, 211 patients remained. Assessment for neurological status and blood chemistry, especially blood coagulation levels (prothrombin time, prothrombin time-international normalized ratio, activated partial thromboplastin time, and serum D-dimer), was performed every week until 1 month after injury. Ultrasonography was performed for DVT detection every 2 weeks. RESULTS: Deep venous thromboses were detected in 22 patients (10.4% of patients studied). All DVT-positive patients demonstrated severe paralysis classified as C or greater on the American Spinal Injury Association (ASIA) Impairment Scale. Multivariate logistic regression of clinical and laboratory parameters revealed that only the D-dimer level at 2 weeks after injury was an accurate predictor of DVT formation. The optimal threshold of D-dimer for prediction was determined to be 16 µg/dL. The sensitivity and specificity for detecting DVT were 77.3% and 69.2%, respectively. CONCLUSIONS: D-dimer levels may be used to predict the likelihood of DVT development in patients with acute cervical SCI. Furthermore, the optimal timing for screening test by D-dimer is 2 weeks after injury, and optimal threshold level for D-dimer for diagnosing DVT is 16 µg/dL. Such a screening test would be cost-efficient and simple to administer and could then be followed with additional investigations, such as ultrasonography or venography.

Radiological Outcome of Short Segment Posterior Instrumentation and Fusion for Thoracolumbar Burst Fractures.

STUDY DESIGN: Retrospective study. PURPOSE: To evaluate the radiological outcome of the surgical treatment of thoracolumbar burst fractures by using short segment posterior instrumentation (SSPI) and fusion. OVERVIEW OF LITERATURE: The optimal surgical treatment of thoracolumbar burst fractures remains a matter of debate. SSPI is one of a number of possible choices, yet some studies have revealed high rates of poor radiological outcome for this SSPI. METHODS: Patients treated using the short segment instrumentation and fusion technique at the Spinal Injuries Center (Iizuka, Fukuoka, Japan) from January 1, 2006 to July 31, 2012 were selected for this study. Radiographic parameters such as local sagittal angle, regional sagittal angle, disc angle, anterior or posterior height of the vertebral body at admission, postoperation and final observation were collected for radiological outcome evaluation. RESULTS: There were 31 patients who met the inclusion criteria with a mean follow-up duration of 22.7 months (range, 12-48 months). The mean age of this group was 47.9 years (range, 15-77 years). The mean local sagittal angles at the time of admission, post-operation and final observation were 13.1°, 7.8° and 14.8°, respectively. There were 71% good cases and 29% poor cases based on our criteria for the radiological outcome evaluation. The correction loss has a strong correlation with the load sharing classification score (Spearman rho=0.64, p<0.001). CONCLUSIONS: The loss of kyphotic correction following the surgical treatment of thoracolumbar burst fracture by short segment instrumentation is common and has a close correlation with the degree of comminution of the vertebral body. Patients with high load sharing scores are more susceptible to correction loss and postoperative kyphotic deformity than those with low scores.

Motion characteristics and related factors of Modic changes in the lumbar spine.

OBJECT Most studies of Modic changes (MCs) have focused on investigating the relationship between MCs and lowback pain, whereas the kinematic characteristics and degenerative disc disease associated with MCs are not well understood. To the authors' knowledge, no previous study has reported on the kinematics of MCs. The purpose of this study was to elucidate the relationship of MCs to segmental motion and degenerative disc disease. METHODS Four hundred fifty symptomatic patients underwent weight-bearing lumbar kinematic MRI in the neutral, flexion, and extension positions. Segmental displacement and intervertebral angles were measured in 3 positions using computer analysis software. Modic changes, disc degeneration, disc bulging, spondylolisthesis, angular motion, and translational motion were recorded, and the relationship of MCs to these factors was analyzed using a logistic regression model. To control the influence of disc degeneration on segmental motion, angular and translational motion were analyzed according to mild and severe disc degeneration stages. The motion characteristics and disc degeneration among types of MCs were also evaluated. RESULTS Multivariate analysis revealed that age, disc degeneration, angular motion, and translational motion were factors significantly related to MCs. In the severe disc degeneration stage, a significant decrease of angular motion and significant increase of translational motion were found in segments with MCs, indicating that a disorder of the endplate had an additional effect on segmental motion. Disc degeneration increased and angular motion decreased significantly and gradually as the type of MC increased. Translational motion was significantly increased with Type 2 MCs. CONCLUSIONS Age, disc degeneration, angular motion, and translational motion were significantly linked to MCs in the lumbar spine. The translational motion of lumbar segments increased with Type 2 MCs, whereas angular motion decreased as the type of MC increased, indicating that Type 2 MCs may have translational instability likely due to degenerative changes. A disorder of the endplates could play an important role in spinal instability.

Diastematomyelia: a surgical case with long-term follow-up.

Few reports have described the involvement of syringomyelia associated with diastematomyelia in the etiology of neurological deficits. We reported a case with syringomyelia associated with diastematomyelia. A female patient with diastematomyelia was followed up clinically over 14 years. At the age of 8, she developed clubfoot deformity with neurological deterioration. Motor function of the right peroneus demonstrated grade 2 in manual muscle tests. Continuous intracanial bony septum and double cords with independent double dura were observed at upper thoracic spine. Magnetic resonance imaging revealed a tethering of the spinal cord and syringomyelia distal to the level of diastematomyelia. Extirpation of the osseum septum and duralplasty were performed surgically. She grew without neurological deterioration during 7 years postoperatively. A long-term followed up case with syringomyelia that was possibly secondary to the tethering of the spinal cord associated with diastematomyelia, and effective treatment with extirpation of the osseum septum and duralplasty was described.