Eiji Mori

Analysis of the risk factors for tracheostomy in traumatic cervical spinal cord injury.

Study Design. A retrospective, consecutive case series. Objective. To determine the risk factors that have a statistically significant association with the need of tracheostomy in patients with cervical spinal cord injury (CSCI) at the acute stage. Summary of Background Data. Respiratory complications remain a major cause of further morbidity and mortality in patients with CSCI. Although several risk factors for tracheostomy have been postulated in these patients, no definitive factors have yet been established according to a multivariate analysis. The use of vital capacity was considered as a single global measure of respiratory function in patients with spinal cord injury, but there are very few studies in which the forced vital capacity was investigated as a risk factor for tracheostomy. Methods. This study that reviewed the clinical data of 319 patients with CSCI, who were evaluated for their neurological impairment within 2 days after injury, was performed. We analyzed the factors postulated to increase the risk for tracheostomy, including patients age, neurological impairment scale grade and level, smoking history, pre-existing medical comorbidities, respiratory diseases, Injury Severity Score, forced vital capacity, and percentage of vital capacity to the predicted value (%VC), using a multiple logistic regression model and classification and regression tree analysis. Results. Of 319 patients, 32 patients received tracheostomy (10.03%). The factors identified using a multiple logistic regression model were high age (69 years of age or older), severe neurological impairment scale, low forced vital capacity (⩽500 mL), and low percentage of vital capacity to the predicted value (<16.3%). The decision tree analysis demonstrated that forced vital capacity, the severe neurological impairment scale, and high patient age were predictive of need for tracheostomy on 94.4% occasions. Conclusion. The measurement of forced vital capacity is indispensable to predict the need for tracheostomy in patients with CSCI at the acute stage.

The potential for functional recovery of upper extremity function following cervical spinal cord injury without major bone injury

Study Design:This was a retrospective observational study.Objectives:The objectives were to describe the prognosis of upper extremity function following cervical spinal cord injury (CSCI), and to identify prognostic factors for functional recovery.Setting:Spinal Injuries Center, Japan.Methods:Sixty patients with C3–4 CSCI without major bone injury participated in the study. Patients were treated nonsurgically and evaluated using the American Spinal Injury Association (ASIA) scales for the upper and lower extremities, their residual cervical motor functions, the modified Frankel grade and an upper extremity function scale. We compared the findings for the upper extremity function scale at 6 months with those for the residual cervical motor functions and modified Frankel grade obtained 3 days after injury.Results:Most patients with CSCI who could flex their hip and knee from a supine position (95%) or who showed some active elbow extension (86%) 3 days after their injury could use a spoon at 6 months. We compared patients who used their fingers at 6 months to those who could not, and observed significant differences in age and ASIA scores for the upper and lower extremities obtained 3 days after injury. A strong correlation was observed between the initial motor scores and the extent of functional recovery at 6 months.Conclusion:Hip and knee flexion from the supine position and elbow extension 3 days after injury significantly predicted a positive prognosis for upper extremity function. Younger age and higher ASIA motor scores obtained 3 days after injury were factors associated with neurological recovery.

Analysis of the risk factors for severity of neurologic status in 216 patients with thoracolumbar and lumbar burst fractures.

Study Design. A retrospective, consecutive case series. Objective. To determine the risk factors that have a significant correlation with the severity of neurologic impairment in thoracolumbar and lumbar burst fractures. Summary of Background Data. The correlation between spinal canal stenosis due to bony fragments and the severity of neurologic deficits in thoracolumbar and lumbar burst fractures remains controversial. Moreover, there have so far been no reports in the literature in which the risk factors (spinal canal stenosis and the disruption of posterior ligamentous complex) causing a severe neurologic deficit were analyzed using a multiple logistic regression model. Methods. A review of the clinical data (neurologic impairments on admission and a finding of posterior ligamentous complex disruption at the time of operation), axial computed tomography, and plain lateral radiography of 216 patients in thoracolumbar (T11–L1) and lumbar (L2–L5) burst fractures was performed. The factors related to neurologic impairments were analyzed using a multiple logistic regression model. Results. In all cases, both the spinal canal stenosis (P < 0.01) and disruption of posterior ligamentous complex (P < 0.01) were significant risk factors. Interestingly, these two risk factors varied according to the injury levels: at thoracic level, the spinal canal stenosis (P < 0.01); at the first lumbar spine, the disruption of the posterior ligamentous complex (P < 0.01); and at the lumbar spine below L2, both of the spinal canal stenosis (P < 0.01) and the disruption of posterior ligamentous complex (P < 0.05) were significant risk factors, respectively. Conclusion. In the patients with thoracolumbar and lumbar burst fractures, the significance of the two important risk factors related to clinical results, namely, the stenosis ratio of spinal canal and the disruption of posterior ligamentous complex, were found to vary depending on the level of injury.

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.

Effect of preservation of the C-6 spinous process and its paraspinal muscular attachment on the prevention of postoperative axial neck pain in C3–6 laminoplasty

OBJECT Axial neck pain after C3-6 laminoplasty has been reported to be significantly lesser than that after C3-7 laminoplasty because of the preservation of the C-7 spinous process and the attachment of nuchal muscles such as the trapezius and rhomboideus minor, which are connected to the scapula. The C-6 spinous process is the second longest spinous process after that of C-7, and it serves as an attachment point for these muscles. The effect of preserving the C-6 spinous process and its muscular attachment, in addition to preservation of the C-7 spinous process, on the prevention of axial neck pain is not well understood. The purpose of the current study was to clarify whether preservation of the paraspinal muscles of the C-6 spinous process reduces postoperative axial neck pain compared to that after using nonpreservation techniques. METHODS The authors studied 60 patients who underwent C3-6 double-door laminoplasty for the treatment of cervical spondylotic myelopathy or cervical ossification of the posterior longitudinal ligament; the minimum follow-up period was 1 year. Twenty-five patients underwent a C-6 paraspinal muscle preservation technique, and 35 underwent a C-6 nonpreservation technique. A visual analog scale (VAS) and VAS grading (Grades I-IV) were used to assess axial neck pain 1-3 months after surgery and at the final follow-up examination. Axial neck pain was classified as being 1 of 5 types, and its location was divided into 5 areas. The potential correlation between the C-6/C-7 spinous process length ratio and axial neck pain was examined. RESULTS The mean VAS scores (± SD) for axial neck pain were comparable between the C6-preservation group and the C6-nonpreservation group in both the early and late postoperative stages (4.1 ± 3.1 vs 4.0 ± 3.2 and 3.8 ± 2.9 vs 3.6 ± 3.0, respectively). The distribution of VAS grades was comparable in the 2 groups in both postoperative stages. Stiffness was the most prevalent complaint in both groups (64.0% and 54.5%, respectively), and the suprascapular region was the most common site in both groups (60.0% and 57.1%, respectively). The types and locations of axial neck pain were also similar between the groups. The C-6/C-7 spinous process length ratios were similar in the groups, and they did not correlate with axial neck pain. The reductions of range of motion and changes in sagittal alignment after surgery were also similar. CONCLUSIONS The C-6 paraspinal muscle preservation technique was not superior to the C6-nonpreservation technique for preventing postoperative axial neck pain.

Influence of spinal cord compression and traumatic force on the severity of cervical spinal cord injury associated with ossification of the posterior longitudinal ligament.

Study Design. Retrospective review. Objective. To evaluate the influence of static compression factors and dynamic factors based on the various degrees of traumatic force on the cervical spinal cord injury (SCI) in patients with ossification of the posterior longitudinal ligament. Summary of Background Data. Spinal cord disorder occurs as a result of various factors, including static factors and traumatic force. Discussions about the severity of paralysis resulting from SCI must therefore focus on dynamic factors based on the traumatic force as well as on static compression factors. However, the past reports did not describe the influence of traumatic force in detail. Methods. Fifty patients presenting with cervical SCI associated with ossification of the posterior longitudinal ligament were included in this study. The American Spinal Injury Association motor score 3 days after injury, the degree of the traumatic force, and the spinal cord compression rate were investigated, and the relationships among these factors were investigated. Results. Paralysis at the time of injury was not determined by static factors alone or by traumatic force alone. The severity of paralysis at the time of injury was determined on the basis of a combination of both the static factors and the degree of traumatic force. Conclusion. Both the degree of spinal cord compression and the degree of traumatic force were found to be important factors associated with the severity of cervical SCI in patients with ossification of the posterior longitudinal ligament. Level of Evidence: 4

Subacute T1-low intensity area reflects neurological prognosis for patients with cervical spinal cord injury without major bone injury

Study design:A retrospective imaging and clinical study.Objectives:To evaluate the relationship between magnetic resonance imaging (MRI) features and neurological prognosis in patients with traumatic cervical spinal cord injury (CSCI) without major bone injury.Methods:A total of 72 patients with CSCI without major bone injury were treated conservatively in our hospital. MRI was performed for all patients at admission and 1 month following injury. We measured the antero-posterior and cranio-caudal diameter of intramedullary intensity changed area with T1-weighted images at the injured segment. Neurological evaluations were performed using the American Spinal Injury Association (ASIA) motor score and the modified Frankel grade at the time of admission and discharge.Results:There was a significant relationship between the antero-posterior diameter ratio of the T1-weighted low-intensity area on MRI at the subacute stage and the ASIA motor score. The optimal threshold of the T1-weighted low-intensity diameter ratio for predicting the patient’s ability to walk with or without assistance at discharge was determined to be 46%. Moreover, 96.8% of the patients with <50% T1-weighted low-intensity area recovered to walk with or without a cane at discharge.Conclusion:The T1-low intensity area may be an important predictive factor for the neurological recovery of CSCI without major bone injury.

A radiographic evaluation of facet sagittal angle in cervical spinal cord injury without major fracture or dislocation

Study Design:A retrospective radiographic study with a minimum 2-year follow-up.Objective:To evaluate the relationships between the cervical articular facets’ morphology and the incidence of traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation.Setting:Spinal Injuries Center, Japan.Methods:This study included 113 patients with traumatic CSCI without major fracture or dislocation. Eighty-four healthy volunteers without neurological deficits or cervical cord pathology on magnetic resonance imaging (MRI) were defined as control subjects. We used a plain sagittal radiograph to measure the facet sagittal angles (FSA) at four cervical segments in all the CSCI patients and controls. We defined the FSA as the angle between the inferior margin of the superior cervical spinal body and the inferior articular process of the superior vertebra.Results:Most frequent incidence of CSCI was seen at C3–4 segment (54%). With respect to CSCI at C3–4 segment, 55.7% of the subjects showed smallest FSA at C3–4 segment.Conclusion:Most of the traumatic CSCI at C3–4 segment showed raised cervical articular facets at C3–4 segment. On the basis of our results, we hypothesized that the raised cervical articular facets might have an important role in the etiology of traumatic CSCI. The cervical spinal cord at the C3–4 segment might receive the highest load during acute hyperextension of the cervical spine because of the C3–4 articular facets’ morphology.