Temporal dynamics of gait function in acute cervical spinal cord injury.

BACKGROUND: Following spinal cord injury (SCI), gait function reaches a post-recovery plateau that depends on the paralysis severity. However, the plateau dynamics during the recovery period are not known. This study aimed to examine the gait function temporal dynamics after traumatic cervical SCI (CSCI) based on paralysis severity. METHODS: This retrospective cohort study included 122 patients with traumatic CSCI admitted to a single specialized facility within 2 weeks after injury. The Walking Index for Spinal Cord Injury II (WISCI II) was estimated at 2 weeks and 2, 4, 6, and 8 months postinjury for each American Spinal Injury Association Impairment Scale (AIS) grade, as determined 2 weeks postinjury. Statistical analysis was performed at 2 weeks to 2 months, 2-4 months, 4-6 months, and 6-8 months, and the time at which no significant difference was observed was considered the time at which the gait function reached a plateau. RESULTS: In the AIS grade A and B groups, no significant differences were observed at any time point, while in the AIS grade C group, the mean WISCI II values continued to significantly increase up to 6 months. In the AIS grade D group, the improvement in gait function was significant during the entire observation period. CONCLUSIONS: The plateau in gait function recovery was reached at 2 weeks postinjury in the AIS grade A and B groups and at 6 months in the AIS grade C group.

Predicting motor function recovery in cervical spinal cord injury-induced complete paralysis with reflex response.

STUDY DESIGN: A retrospective clinical study. OBJECTIVE: To elucidate the usefulness of the patellar tendon reflex (PTR), bulbocavernosus reflex (BCR), and plantar response (PR) as factors in the prognostic prediction of motor function in complete paralysis due to cervical spinal cord injuries (CSCIs) at the acute phase. SETTING: Department of Orthopedic Surgery, Spinal Injuries Center, Japan. METHODS: 99 patients assessed as the American Spinal Injury Association Impairment Scale (AIS) grade A (AIS A) were included in this study. The PTR, BCR, and PR were evaluated respectively as positive or negative at the time of injury. We classified the patients into two groups based on their neurological recovery at 3 months after injury: "recovered" group was defined as AIS C, D, or E; "non-recovered" group was defined as AIS A or B. RESULTS: Eight patients demonstrated positive PTR, while 91 demonstrated negative. Three out of eight patients with positive PTR (37.5%) were R group, while 83 out of 91 patients with negative PTR (91.2%) were N group. A significant difference was observed (p = 0.043). For BCR, no significant difference was observed (p > 0.05). Twenty-six patients demonstrated positive PTR, while 73 demonstrated negative. Nine out of twenty-six patients with positive PR (34.6%) were R group, while 71 out of 73 patients with negative PR (97.3%) were N group. A significant difference was observed (p = 0.000068). CONCLUSION: The PTR and PR are useful for poor prognostic prediction of motor function in CSCI at the acute phase.

Traumatic cervical spinal cord injury after cervical laminoplasty for ossification of posterior longitudinal ligament: a case series.

STUDY DESIGN: A retrospective review of a case series of five participants. OBJECTIVE: To elucidate the effects of post-cervical laminoplasty on the clinical pathophysiology of traumatic CSCI. Cervical laminoplasty has been widely performed with good results in individuals for cervical myelopathy. However, no reports have thus far referred to the incidence of traumatic cervical spinal cord injury (CSCI) after previous history of cervical laminoplasty. SETTING: Spinal Injuries Center, Japan. METHODS: From 2008 to 2017, 999 cervical myelopathy individuals were treated by cervical laminoplasty in our institution. Of these, only five participants were subsequently emergency transported to our institution caused by traumatic CSCI. The pathology of five participants were cervical ossification of posterior longitudinal ligament (C-OPLL). The changes of cervical sagittal range of motion (ROM) and the morphology of OPLL were radiologically evaluated. Moreover, the mechanism of injury, the level of injury, and neurological evaluations were discussed. RESULTS: All of the participants demonstrated ankylosed cervical spine due to developing OPLL and spontaneous bony facet and laminar fusion on post-laminoplasty. A significant difference in cervical ROM was observed between pre-laminoplasty and 6 months post-laminoplasty (p = 0.0065). Three participants were extension injury and the other two were flexion injury. CONCLUSIONS: All of the five traumatic CSCI participants had a history of previous cervical laminoplasty for C-OPLL. Cervical laminoplasty for C-OPLL might lead to cervical spine with rigidity and ankylosing due to developing OPLL and bony facet and laminar fusion, and might have a risk for traumatic CSCI.

The time course of dysphagia following traumatic cervical spinal cord injury: a prospective cohort study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To elucidate serial changes in dysphagia and elucidate the critical period for dysphagia following acute traumatic cervical spinal cord injury (CSCI). SETTING: Spinal Injuries Center, Fukuoka, Japan. METHODS: We prospectively examined individuals with acute traumatic CSCI admitted within 2 weeks after injury. Severity of dysphagia was evaluated using both the dysphagia severity scale (DSS) and functional oral intake scale (FOIS) at 2 weeks, 1 month, 2 months, and 3 months after injury. Condition of oral intake before injury was assessed by history taking. American Spinal Injury Association (ASIA) impairment scale grade and motor scores were also assessed at the same timepoints, and the correlation between dysphagia and paresis was analyzed. RESULTS: Sixty-five individuals with CSCI were assessed consecutively for 3 months after injury. Swallowing function, evaluated using both the DSS and FOIS, was significantly decreased at 2 weeks after injury, but significantly improved thereafter. Significant correlations between severity of dysphagia (DSS and FOIS scores) and motor scores were found at 2 weeks after injury (rs = 0.66 and 0.61; p < 0.001 and p < 0.001, respectively), indicating that individuals with lower motor scores had more severe swallowing dysfunction. CONCLUSIONS: Dysphagia occurred immediately after injury, but gradually improved over time. Individuals with more severe paralysis had significantly more severe dysphagia. Special attention for dysphagia should be paid to individuals with severe paralysis in acute phase.

How much time is necessary to confirm the diagnosis of permanent complete cervical spinal cord injury?

STUDY DESIGN: Retrospective chart audits. OBJECTIVE: To investigate the optimal timing at which permanent complete cervical spinal cord injury (CSCI) can be confirmed when evaluating paralysis caused by traumatic CSCI. SETTING: Department of Orthopedic Surgery, Spinal Injuries Center, Japan. METHODS: Two-hundred and three patients with CSCI that was classified with an American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A (AIS A) within 72 h of the initial diagnosis of traumatic CSCI were included in the present study. Neurological data from the time of the initial diagnosis to 1 year after the injury were extracted. The number of those with recovery from AIS A and changes of AIS in the recovery were examined. RESULTS: Thirty-five of 203 (17%) patients whose injuries were initially classified with an AIS A showed recovery from AIS A. Thirty-four of 35 (97%) patients showed recovery from AIS A within 8 weeks after injury. CONCLUSION: If CSCI patients with AIS A have not recovered by 8 weeks, the likelihood that they will recover from AIS A is marginal. However, this conversely means that we must consider the possibility that a patient with a traumatic CSCI classified with an AIS A may still show recovery from AIS A within the first 8 weeks after injury.

Probing molecular bond-length using molecular-frame photoelectron angular distributions.

The molecular-frame photoelectron angular distributions (MFPADs) in O 1s photoemission from CO2 molecule were measured. Patterns due to photoelectron diffractions were observed in the MFPADs. The polarization-averaged MFPADs were compared with theoretical calculation and were found to be useful in determining the molecular bond-length, which is a component to determine molecular structures.

The dosage and administration of long-term intrathecal baclofen therapy for severe spasticity of spinal origin.

STUDY DESIGN: Retrospective chart audit. OBJECTIVE: To indicate the appropriate baclofen dosage to control severe spasticity of spinal origin and to develop the optimal administration protocol for long-term intrathecal baclofen (ITB) therapy. SETTING: Department of Orthopaedic Surgery, Spinal Injuries Center, Japan. METHODS: Thirty-four people with spasticity of various spinal origins who were consistently treated at our hospital were included. The median follow-up period was 6 years and 11 months. Measures of Ashworth score were taken before and after surgical implant of baclofen pump. We decided not to increase the baclofen dosage after the Ashworth score reached 1. We recorded the control of spasticity, changes in the baclofen dose, and the incidence of complications. RESULTS: The average Ashworth score was 3.31 (1.75-4.0) before implant surgery, 1.38 (1.0-2.25) after implant surgery, and 1.39 (1.0-2.25) at the final follow-up, while the average baclofen dose (therapeutic/optimal dose) was 230.6 µg/day (50-450). The incidence of each complication was as follows: 8.8% (n = 3) catheter-related, 2.9% (n = 1) pump-related and 5.9% (n = 2) drug tolerance. No patients experienced withdrawal syndrome. Dose fluctuation with changes in the pathology of the original disease was observed in three cases. CONCLUSIONS: The usage of the Ashworth score as a guide for dose adjustment was found to be a good objective indicator for ITB therapy. The administration based on this objective indicator made it possible to effectively manage patients with a relatively low dose of baclofen and a low rate of drug-related complications.

Conventional JOA score for cervical myelopathy has a rater's bias -In comparison with JOACMEQ.

BACKGROUND: The JOA (Japan Orthopaedic Association) score has been a standard outcome measure to evaluate cervical myelopathy in Japan. Despite its reliability and convenience, there can be a rating bias in the JOA score. The current study was conducted to delineate the rater's bias of the JOA score by comparing it with a new objective outcome measure. METHODS: Two hundred and thirty four operative candidates with cervical myelopathy were included in the study. The patients were divided into four groups according to the surgeon (92 patients in group A, 60 patients in group B, 38 patients in group C and 44 patients in group D). Each patient's preoperative JOA score was exclusively recorded by the surgeon himself, while JOACMEQ (Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire) was recorded by each patient. Disease severity, the most important prognostic factor, was equalized between patient groups by a special statistical method called inverse-probability weighting (IPW). To define similarity of the two groups, Cohen's d was used. RESULTS: After the adjustment, the differences of the JOA score were only 0.1 between groups A and D and 0 between groups B and C. The values of Cohen's d were also very small both between groups A and D (3%), and between groups B and C (0.3%). The averaged JOA scores of groups A and D were higher by 0.4-0.8 than those of groups B and C, while the averaged JOA scores were almost the same both between groups A and D, and between groups B and C. Surgeons A and D had the same tendency to give higher JOA scores than surgeons B and C did. CONCLUSIONS: The current study confirmed there is a definite rater's bias in the JOA score. JOACMEQ is to be applied as a more reliable outcome measure to evaluate myelopathy patients.

Verification of the Accuracy of Cervical Spinal Cord Injury Prognosis Prediction Using Clinical Data-Based Artificial Neural Networks.

BACKGROUND: In patients with cervical spinal cord injury (SCI), we need to make accurate prognostic predictions in the acute phase for more effective rehabilitation. We hypothesized that a multivariate prognosis would be useful for patients with cervical SCI. METHODS: We made two predictive models using Multiple Linear Regression (MLR) and Artificial Neural Networks (ANNs). We adopted MLR as a conventional predictive model. Both models were created using the same 20 clinical parameters of the acute phase data at the time of admission. The prediction results were classified by the ASIA Impairment Scale. The training data consisted of 60 cases, and prognosis prediction was performed for 20 future cases (test cohort). All patients were treated in the Spinal Injuries Center (SIC) in Fukuoka, Japan. RESULTS: A total of 16 out of 20 cases were predictable. The correct answer rate of MLR was 31.3%, while the rate of ANNs was 75.0% (number of correct answers: 12). CONCLUSION: We were able to predict the prognosis of patients with cervical SCI from acute clinical data using ANNs. Performing effective rehabilitation based on this prediction will improve the patient's quality of life after discharge. Although there is room for improvement, ANNs are useful as a prognostic tool for patients with cervical SCI.

Halo vest fixation effectively maintains cervical alignment through intraoperative repositioning in patients with cervical spine instability.

Introduction: The objective of this study was to examine if halo vest fixation provides sufficient stabilization of cervical spine alignment to endorse its use through intraoperative positional changes in patients with cervical spine instability. Methods: The subjects of this study were 14 patients with cervical spine instability who were immobilized in halo vests until they underwent subsequent internal fixation surgery. After induction of anesthesia, the patients in halo vests were repositioned from the supine position to the prone position. The halo ring was fixed to the surgical table and the dorsal struts and vest were removed for surgery. Radiographs obtained in the preoperative sitting position and intraoperative prone position were compared for the following measures of cervical alignment: O-C2 angle, C2-C6 angle, pharyngeal inlet angle (PIA), atlantodental interval (ADI), Redlund-Johnell (R-J) value as a measure of O-C2 length, O-C6 length, and O-C2 length/O-C6 length (%). Results: There were no significant differences in O-C2 angle, C2-C6 angle, PIA, ADI, or O-C2 length/O-C6 length (%). However, the R-J value and O-C6 length were significantly higher in the intraoperative prone position than in the preoperative sitting position. None of the patients presented with any complications, including dysphagia or neurological deterioration. Conclusions: Our results suggest that when patients are repositioned to the prone position while immobilized in halo vests, the cervical spine is distracted in the cephalocaudal direction across all cervical segments but the cervical alignment is sufficiently maintained. Halo vests are a highly effective external fixation method for patients with cervical spine instability, allowing for a safe repositioning to the prone position for surgery while preserving cervical alignment and preventing neurological deterioration.

Changing trends in traumatic spinal cord injury in an aging society: Epidemiology of 1152 cases over 15 years from a single center in Japan.

Traumatic spinal cord injury (TSCI) causes an insult to the central nervous system, often resulting in devastating temporary or permanent neurological impairment and disability, which places a substantial financial burden on the health-care system. This study aimed to clarify the up-to-date epidemiology and demographics of patients with TSCI treated at the largest SCI center in Japan. Data on all patients admitted to the Spinal Injuries Center with TSCI between May 2005 and December 2021 were prospectively collected using a customized, locally designed SCI database named the Japan Single Center Study for Spinal Cord Injury Database (JSSCI-DB). A total of 1152 patients were identified from the database. The study period was divided into the four- or five-year periods of 2005-2009, 2010-2013, 2014-2017, and 2018-2021 to facilitate the observation of general trends over time. Our results revealed a statistically significant increasing trend in age at injury. Since 2014, the average age of injury has increased to exceed 60 years. The most frequent spinal level affected by the injury was high cervical (C1-C4: 45.8%), followed by low cervical (C5-C8: 26.4%). Incomplete tetraplegia was the most common cause or etiology category of TSCI, accounting for 48.4% of cases. As the number of injuries among the elderly has increased, the injury mechanisms have shifted from high-fall trauma and traffic accidents to falls on level surfaces and downstairs. Incomplete tetraplegia in the elderly due to upper cervical TSCI has also increased over time. The percentage of injured patients with an etiology linked to alcohol use ranged from 13.2% (2005-2008) to 19% (2014-2017). Given that Japan has one of the highest aging populations in the world, epidemiological studies in this country will be very helpful in determining health insurance and medical costs and deciding strategies for the prevention and treatment of TSCI in future aging populations worldwide.

Clinical relationship between cervical spinal canal stenosis and traumatic cervical spinal cord injury without major fracture or dislocation.

PURPOSE: The purpose of the study was to evaluate the clinical relationship between cervical spinal canal stenosis (CSCS) and incidence of traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation, and to discuss the clinical management of traumatic CSCI. METHODS: Forty-seven patients with traumatic CSCI without major fracture or dislocation (30 out of 47 subjects; 63.83 %, had an injury at the C3-4 segment) and 607 healthy volunteers were measured the sagittal cerebrospinal fluid (CSF) column diameter at five pedicle and five intervertebral disc levels using T2-weighted midsagittal magnetic resonance imaging. We defined the sagittal CSF column diameter of less than 8 mm as CSCS based on the previous paper. We evaluated the relative and absolute risks for the incidence of traumatic CSCI related with CSCS. RESULTS: Using data from the Spinal Injury Network of Fukuoka, Japan, the relative risk for the incidence of traumatic CSCI at the C3-4 segment with CSCS was calculated as 124.5:1. Moreover, the absolute risk for the incidence of traumatic CSCI at the C3-4 segment with CSCS was calculated as 0.00017. CONCLUSIONS: In our results, the relative risk for the incidence of traumatic CSCI with CSCS was 124.5 times higher than that for the incidence without CSCS. However, only 0.017 % of subjects with CSCS may be able to avoid developing traumatic CSCI if they undergo decompression surgery before trauma. Our results suggest that prophylactic surgical management for CSCS might not significantly affect the incidence of traumatic CSCI.

Significance of the neurological level of injury as a prognostic predictor for motor complete cervical spinal cord injury patients.

Objective: To investigate the usefulness of the combination of neurological findings and magnetic resonance imaging (MRI) as a prognostic predictor in patients with motor complete cervical spinal cord injury (CSCI) in the acute phase.Design: A cross-sectional analysisSetting: Department of Orthopaedic Surgery, Spinal Injuries CenterParticipants/Methods: Forty-two patients with an initial diagnosis of motor complete CSCI (AIS A, n = 29; AIS B, n = 13) within 72 h after injury were classified into the recovery group (Group R) and the non-recovery group (Group N), based on the presence or absence of motor recovery (conversion from AIS A/B to C/D) at three months after injury, respectively. The Neurological Level of Injury (NLI) at the initial diagnosis was investigated and the presumptive primary injured segment of the spinal cord was inferred from MRI performed at the initial diagnosis. We investigated whether or not the difference between the presumptive primary injured segment and the NLI exceeded one segment. The presence of a difference between the presumptive primary injured segment and the NLI was compared between Groups R and N.Results: The number of cases with the differences between the presumptive primary injured segment and the NLI was significantly higher in Group N than in Group R.Conclusion: The presence of differences between the presumptive primary injured segment and the NLI might be a poor improving prognostic predictor for motor complete CSCI. The NLI may be useful for predicting the recovery potential of patients with motor complete CSCI when combined with the MRI findings.

Incidence and risk factors of pneumonia following acute traumatic cervical spinal cord Injury.

OBJECTIVES: To elucidate the incidence and risk factors for pneumonia after acute traumatic cervical spinal cord injury (CSCI). DESIGN: Retrospective cohort study.Setting: Spinal injuries center in Japan.Participants: Of 184 individuals who were admitted within 2 weeks after acute traumatic cervical spinal injuries, 167 individuals who met the criteria were included in this study.Interventions: The occurrence of pneumonia, degree of dysphagia using the Dysphagia Severity Scale, patient age, history of smoking, presence of tracheostomy, vital capacity, level of injury, and the American Spinal Injury Association Impairment Scale (AIS) 2 weeks after injury were assessed.Outcomes: Incidence of pneumonia were analyzed. Moreover, the risk factors of pneumonia were evaluated using logistic regression analysis. RESULTS: From the 167 individuals who met the criteria, 30 individuals (18%) had pneumonia; in 26 (87%) of these individuals, pneumonia was aspiration related, defined as Dysphagia Severity Scale ≤ 4. The median occurrence of aspiration pneumonia was 11.5 days after injury. A logistic regression analysis revealed that severe AIS and severe Dysphagia Severity Scale scores were significant risk factors of pneumonia after CSCI. CONCLUSIONS: It was highly likely that the pneumonias following CSCI were related to aspiration based on the Dysphagia Severity Scale. In addition, most of the patients developed aspiration pneumonia within 1 month after injury. Aspiration and severe paralysis were significant risk factors for pneumonia. The treatment of dysphagia in the acute phase should be considered an important indicator to prevent pneumonia.

Time Course and Characteristics of the Nutritional Conditions in Acute Traumatic Cervical Spinal Cord Injury.

Introduction: This retrospective cohort study aimed to examine the nutritional time course and elucidate the critical period of undernutrition following acute traumatic cervical spinal cord injury (CSCI). Methods: The study was performed at a single facility that treated spinal cord injuries. We examined individuals with acute traumatic CSCI admitted to our hospital within 3 days of injury. Both prognostic nutritional index (PNI) and controlling nutritional status (CONUT) scores, which objectively reflect nutritional and immunological conditions, were assessed at admission and 1, 2, and 3 months after the injury. The American Spinal Injury Association impairment scale (AIS) categorizations and severity of dysphagia were evaluated at these time points. Results: A total of 106 patients with CSCI were evaluated consecutively for 3 months after injury. Individuals with AIS categorizations of A, B, or C at 3 days after injury were significantly more undernourished than those with an AIS categorization of D at 3 months after injury, indicating that individuals with mild paresis better maintained their nutritional condition after injury. Nutritional conditions, as assessed by both PNI and CONUT scores, improved significantly between 1 and 2 months after injury, whereas no significant differences were found between admission and 1 month after injury. Nutritional status and dysphagia were significantly correlated at each time point (p<0.001), indicating that swallowing dysfunction is an important factor associated with malnutrition. Conclusions: Nutritional conditions showed significant gradual improvements from 1 month after the injury. We must pay attention to undernutrition, which is associated with dysphagia, especially in individuals with severe paralysis during the acute phase following injury.

Intraoperative Radiation Exposure from O-arm-based 3D Navigation in Spine Surgery.

Introduction: Intraoperative three-dimensional (3D) imaging guide technology, such as the O-arm surgical imaging system, is a beneficial tool in spinal surgery that provides real-time 3D images of a patient's spine. This study aims to determine the exposure dose from intraoperative O-arm imaging. Methods: A consecutive retrospective review of all patients undergoing spinal surgery was conducted between June 2019 and August 2022. Demographic and operative data were collected from electronic medical records. Results: Intraoperative O-arm imaging was conducted in 206 (12.9%) of 1599 patients, ranging from one to 4 scans per patient (1.17±0.43 scans). Single O-arm imaging enabled navigation of seven vertebrae in the cervical spine, seven in the thoracic spine, five in the thoracolumbar spine, and four in the lumbar spine on average. The number of O-arm shots per surgery was 1.15±0.36, 1.06±0.24, 1.61±0.7, and 1.07±0.25 for cervical, thoracic, thoracolumbar, and lumbar spinal cases, respectively. The exposure doses represented by dose length products in single O-arm imaging were 377±19 mGy-cm, 243±22 mGy-cm, 378±38 mGy-cm, and 258±11 mGy-cm for cervical, thoracic, thoracolumbar, and lumbar spine cases, respectively. We observed a weak positive correlation between the number of fused spinal levels and the exposure dose. Conclusions: Intraoperative radiation exposure from O-arm imaging was lower than the national diagnostic reference levels in Japan established based on the International Commission on Radiological Protection publication, demonstrating its safety from the standpoint of radiological protection in most cases. In surgeries with a large range of fixations, such as corrective deformity surgery, the number of imaging sessions and the amount of intraoperative radiation exposure would increase, leading surgeons to pay attention to the risk of radiation in spinal surgery.

Predicting the Progression of Spasticity in the Early Phase of Spinal Cord Injury: A Prospective Cohort Study.

Spasticity-defined as involuntary movements caused by insult to upper motor neurons after spinal cord injury (SCI)-interferes with patients' activities of daily living. Spasticity is generally identified and managed in the chronic phase of SCI, but few reports have examined the onset of spasticity after injury. The purpose of this study is to elucidate serial changes in spasticity after SCI and clarify the timing of severe spasticity. We prospectively examined individuals with acute traumatic SCI admitted within two weeks after injury. Severity of spasticity was evaluated using the Modified Ashworth Scale (MAS) at 2, 4, 6, and 8 weeks, followed by 3, 4, 5, and 6 months after injury. After completing evaluation of the cohort, the patients were divided into two groups: a spasticity group with MAS scores ≥3 (marked increase in muscle tone through most of the range of motion (ROM)) in at least one joint movement within 6 months of injury and a control group with MAS scores ≤2 in all joint movements throughout the 6 months after injury. Neurological findings such as the American Spinal Injury Association (ASIA) Impairment Scale grades and ASIA motor scores were also assessed at all time points, and the correlations between the onset of spasticity, severity of spasticity, and neurological findings were analyzed. There were 175 patients with traumatic SCI who were assessed consecutively for 6 months after injury. The MAS scores of the group significantly increased over time until 4 months after injury. The spasticity group had significantly higher MAS scores compared with the control group as early as 2 weeks post-injury. We found that the patients with earlier onset of spasticity had higher final MAS scores. No correlation was found between the ASIA Impairment Scale grade and the onset of spasticity. Our results reveal that the development of severe spasticity may be predictable from as early as 2 weeks after SCI, suggesting that early therapeutic intervention to mitigate problematic spasticity may enhance the benefits of post-injury rehabilitation.

The pathophysiology of cervical spinal cord injury: what are the differences between traumatic injury and degenerative disorder.

STUDY DESIGN: Retrospective comparative clinical study. OBJECTIVE: To establish eligible diagnostic criteria for traumatic cervical spinal cord injury (TCSCI) without major fracture or dislocation and create a definitive clinical protocol by comparing the pathophysiology of CSCI in both traumatic and degenerative disorders. SETTING: Fukuoka, Japan. METHODS: A total of 21 TCSCI patients and 16 rapid progressive clinical deterioration of cervical spondylotic myelopathy (rp-CSM: additional cervical spinal cord injury with an existing cervical myelopathy) patients with impairment graded as C or D on the American Spinal Injury Association (ASIA) Impairment Scale were included in the study. Magnetic resonance (MR) images and ASIA motor scores were evaluated for all of the patients at the time of admission and 12 months postoperatively. RESULTS: The T2-weighted MR images for all patients showed an abnormally high intramedullary signal in the area of the injured segment at the first examination. At 12 months post-surgery, 47.62% of patients with TCSCI and none with rp-CSM had an abnormally low intramedullary signal change on T1-weighted MR images. The neurological improvement with rp-CSM was significantly greater than that with TCSCI at 12 months postoperatively. CONCLUSIONS: Our results suggest that the pathophysiology of CSCI between traumatic injury and degenerative disorder are similar, but not identical. The most important factor in the early pathophysiological differential diagnosis between these two pathologies is the presence of an existing cervical myelopathy. We believe that early prognosis with eligible diagnosis for CSCI may lead to early preparations for social rehabilitation in each case.

Technical note: The impact of storage humidity on the response of reference-class ionization chambers.

PURPOSE: A number of Farmer-type ionization chambers were tested against storage humidity to confirm whether they satisfied the criteria for the long-term stability of reference-class ionization chambers. METHODS: The ionization chambers were stored for several months in an environment with relative humidity adjustable from 20% to 80%. The ionization chambers were removed from the storage environment at variable intervals ranging from 1 to 70 days and irradiated in a Co-60 radiation beam. The responses for each ionization chamber were evaluated from the measured currents corrected for the atmospheric air density, and were compared with those predicted by the Co-60 half-life. RESULTS: Certain ionization chambers gave a constant relative response regardless of the storage humidity, while the relative responses of two types of ionization chambers changed as a function of the storage humidity. The difference between the relative responses for the low (20-30%) and high (70-80%) storage relative humidity was ∼ $\sim$ 0.7%. The response was larger for the high relative humidity storage. Immediately after the storage humidity changed, the relative response started to change by the day, and it took approximately 2 weeks to 2 months for the relative response to converge. For one type of the ionization chamber, the plastic outer wall and the outer electrode were replaced with those made of solid graphite, and it was confirmed that the remodeled ionization chamber did not exhibit the response change. CONCLUSIONS: The present results and previous reports by other authors indicate that the magnitude of the change depends on the magnitude of the water absorption of the plastic used for the outer wall and/or the electrode of the ionization chamber. Thus, it is important in the selection of the reference-class ionization chamber to note the material and structure of the outer wall and electrode of the ionization chamber. If the ionization chamber has a hygroscopic wall and electrode and it is used as a reference ionization chamber, it is necessary to pay additional attention to the humidity difference for the storage, daily irradiation, and yearly calibration especially in regions with large seasonal humidity fluctuations.