Potential of intraoperative ultrasonographic assessment of the spinal cord central echo complex in predicting postoperative neurological recovery of degenerative cervical myelopathy.

BACKGROUND AND PURPOSE: The spinal cord central echo complex (SCCEC) is a special ultrasonography-based intramedullary structure, but its clinical significance in degenerative cervical myelopathy (DCM) is undefined. This study aimed to explore the potential of the SCCEC in predicting postoperative neurological recovery in DCM. METHODS: Thirty-two DCM patients who underwent intraoperative ultrasonography-guided French-door laminoplasty were prospectively enrolled. The modified Japanese Orthopaedic Association (mJOA) score was evaluated preoperatively and 12 months postoperatively. SCCEC width (SCCEC-W), and anteroposterior diameter (APD) and transverse diameter (TD) of the spinal cord were measured on transverse ultrasonographic images, while the tissue widths from anterior and posterior borders of the spinal cord to the SCCEC were measured on sagittal ultrasonographic images. The APD of the spinal cord and occupying rate of the spinal canal were measured on preoperative magnetic resonance imaging (MRI). RESULTS: All patients achieved improvements in mJOA scores, with an average recovery rate (RR) of 68.69 ± 20.22%. Spearman correlation analysis revealed that SCCEC-W, and ratios between the SCCEC-W and APD/TD based on ultrasonography, correlated moderately with mJOA score RR, with coefficients of -0.527, -0.605 and -0.514, respectively. The ratio between SCCEC-W and ultrasonographic TD correlated moderately with preoperative APD of the spinal cord. The MRI measurements and ultrasonography-based tissue widths showed no significant correlation with mJOA score RR. CONCLUSIONS: The SCCEC may have predictive potential as an intraoperative indicator of neurological recovery in treating DCM. SCCEC-W may be related to spinal cord compression in DCM.

Assessment of degenerative cervical stenosis on T2-weighted MR imaging: sensitivity to change and reliability of mid-sagittal and axial plane metrics.

STUDY DESIGN: A retrospective cross-sectional study. OBJECTIVE: To assess the sensitivity to change and reliability of various mid-sagittal and axial plane metrics in the assessment of patients with single-level degenerative cervical stenosis on T2-weighted MR imaging. SETTING: A diagnostic MR imaging facility in Sydney (Australia). METHODS: We retrospectively reviewed T2-weighted MR images of 85 consecutive patients (48 M and 37 F) with single-level degenerative cervical stenosis. Canal compromise and cord compression were evaluated using three mid-sagittal plane metrics (M1, M2, and M3) and two axial plane metrics (M4 and M5), at the level of stenosis and nonstenotic cephalad and caudal levels (controls). Sensitivity to change (SC) for each metric was evaluated as the percentage deviation of the measured value from the estimated normal value based on cephalad and caudal controls. Reliability for each metric was evaluated using intraclass correlation coefficients. RESULTS: Degenerative cervical stenosis showed a bimodal distribution peaking at C5-6 (n = 32) and C3-4 (n = 29) levels. The changes in the canal and cord geometry along the rostrocaudal axis were inconsistent. Across all individual subjects (reflecting a range of stenosis severity), M3 (-32.87% ± 10.60%) was more sensitive to change compared with M1 (16.64% ± 16.48%) and M2 (-23.95% ± 11.12%). Similarly, M4 (-24.62% ± 12.17%) was more sensitive to change compared with M5 (-6.71% ± 11.08%). The level of reliability was "moderate" to "excellent" for mid-sagittal plane measurements, and "poor" to "excellent" for axial plane measurements. CONCLUSION: Changes in canal dimensions in the mid-sagittal plane and cord shape in the axial plane are sensitive indicators of degenerative cervical stenosis on T2-weighted MR images.

Assessment and Management of Patients With Metastatic Spinal Cord Compression: A Multidisciplinary Review.

PURPOSE: Metastatic spinal cord compression (MSCC) can be a catastrophic manifestation of advanced cancer that causes immobilizing pain and significant neurologic impairment. Oncologists can protect their patients by having a high index of suspicion for MSCC when patients present with new or worsening back pain before motor, sensory, bowel, or bladder deficits develop. We provide an updated, evidence-based narrative review of the presentation, diagnosis, and treatment of MSCC. METHODS: This narrative review was conducted by searching MEDLINE and Cochrane Database of Systematic Reviews for relevant literature on the presentation, diagnosis, and treatment of patients with MSCC. The article addresses the key elements of MSCC management germane to the medical oncologist, with special attention given to pain and symptom management, decision making with regard to surgery and radiation therapy, the importance of rehabilitative care, and the value of a multidisciplinary approach. RESULTS: Magnetic resonance imaging of the entire spine is recommended for the diagnosis of MSCC. Treatment includes glucocorticoid therapy, pain management, radiation therapy with or without surgery, and specialized rehabilitation. When formulating a treatment plan, clinicians should consider the patient's care goals and psychosocial needs. CONCLUSION: Prompt diagnosis and treatment of MSCC can reduce pain and prevent irreversible functional loss. Regular collaboration among multidisciplinary providers may streamline care and enhance achievement of treatment goals.

Assessment of Intrathecal Pressure in Chondrodystrophic Dogs With Acute Thoracolumbar Disk Disease.

OBJECTIVES: To assess intrathecal pressure (ITP) in chondrodystrophic dogs with thoracolumbar disk extrusion. STUDY DESIGN: Prospective cohort study. ANIMALS: Group 1: 11 chondrodystrophic dogs with thoracolumbar disk extrusion and present deep pain sensation. Group 2 (control): 3 healthy chondrodystrophic laboratory dogs without spinal disease. METHODS: Diagnosis was based on neurologic signs, magnetic resonance imaging (MRI) findings, and surgical confirmation. Blood pressure was maintained within physiologic range during anesthesia. A standardized surgical procedure was applied to minimize factors that could influence measurement readings. An extended hemilaminectomy was performed and ITP was measured with a fiber optic catheter. The catheter was inserted in the subarachnoid space 1 spinal segment caudal to the level of herniation and its tip was advanced to the site of compression. RESULTS: Significantly higher ITP occurred in chondrodystrophic dogs with acute thoracolumbar disk disease compared with controls. ITP was not associated with duration of clinical signs, neurologic status, outcome, degree of spinal cord compression, or signal intensity changes as assessed by MRI. CONCLUSION: Acute thoracolumbar disk disease leads to elevated ITP in chondrodystrophic dogs, which may contribute to increased compression of spinal cord parenchyma.

Quantitative assessment of column-specific degeneration in cervical spondylotic myelopathy based on diffusion tensor tractography.

PURPOSE: Cervical spondylotic myelopathy (CSM) is a common spinal cord disorder in the elderly. Diffusion tensor imaging (DTI) has been shown to be of great value for evaluating the microstructure of nerve tracts in the spinal cord. Currently, the quantitative assessment of the degeneration on the specific tracts in CSM is still rare. The aim of the present study was to use tractography-based quantification to investigate the column-specific degeneration in CSM. METHODS: A total of 43 volunteers were recruited with written informed consent, including 20 healthy subjects and 23 CSM patients. Diffusion MRI was taken by 3T MRI scanner. Fiber tractography was performed using TrackVis to reconstruct the white matter tracts of the anterior, lateral and posterior column on the bilateral sides. The DTI metrics acquired from tractography, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD), were compared between healthy subjects and CSM patients. RESULTS: Compared to healthy subjects, FA was found significantly lower in the lateral (Healthy 0.64 ± 0.07 vs. CSM 0.53 ± 0.08) and posterior column (Healthy 0.67 ± 0.08 vs. CSM 0.47 ± 0.08) (p < 0.001), while MD, AD and RD were significantly higher in the anterior, lateral and posterior column in CSM (p < 0.05). CONCLUSION: Loss of microstructural integrity was detected in the lateral and posterior column in CSM. Tractography-based quantification was capable of evaluating the subtle pathological insult within white matter on a column-specific basis, which exhibited potential clinical value for in vivo evaluation of the severity of CSM.

Acute spinal cord compression: CQI framework increases resource efficiency while promoting delivery of high-quality care.

PURPOSE: Literature reports indicate that advanced imaging is overutilized, especially in the emergency setting. At our institution, stat spinal MRI for suspected acute spinal cord compression (ASCC) was perceived to be excessively utilized. A continuous quality improvement process was employed to investigate this trend and improve the efficiency of this diagnosis. METHODS: Spine imaging in patients with suspected ASCC was retrospectively evaluated for appropriateness of indications and quality of imaging. Based on the results, a new institutional policy for ordering MR for suspected ASCC was implemented, concurrent with development of a new screening spine MRI protocol. Subsequently, indications, efficacy, and imaging utilization of the new strategy were analyzed for improved operational effectiveness. RESULTS: The initial retrospective study demonstrated only a 1.4% positive rate of ASCC as well as image-quality degradation due to patient motion resulting from prolonged scan times. Based on these results, a new institutional policy for ordering stat ASCC spine MRI was instituted with an updated screening MRI protocol. This policy resulted in a positive rate of ASCC of 4.4%, and decreased scan time by 50%-70%, while preserving diagnostic image quality and decreasing resource utilization. CONCLUSIONS: As suspected, stat spinal MRI for ASCC was excessively utilized at our institution. The study demonstrated that systemic improvements regarding this issue can be achieved by using a multidisciplinary approach and following a continuous quality improvement methodology. A new MRI protocol for identification of ASCC was found to preserve image quality and diagnostic confidence, while simultaneously decreasing scan time and use of valuable health care resources.

Usefulness of diffusion tensor MR imaging in the assessment of intramedullary changes of the cervical spinal cord in different stages of degenerative spine disease.

PURPOSE: The aim of this study was to evaluate the usefulness of diffusion tensor imaging (DTI) in the detection of cervical spinal cord integrity alterations in different stages of degenerative spine disease, as well as to compare DTI parameters with selected cervical spinal stenosis measurements. METHODS: One hundred and thirty-two symptomatic patients (mean age 53.58 years) with different stages of cervical spondylosis and twenty-five control subjects (mean age 45.78 years) were enrolled in the study. DTI was performed with a 1.5 T MR scanner. Three hundred and forty-nine spine segments from C2/C3 to C5/C6 were evaluated and divided into five groups according to the degree of spinal cord compression. The values of fractional anisotropy (FA) and apparent diffusion coefficient at each level were calculated and their correlations with the degree of stenosis were analyzed. RESULTS: FA values differed significantly (p < 0.0001) at all levels between the control group and patients with cervical degenerative disease, including subjects without spinal cord compression visible on plain MR images. A significant (p < 0.01) positive correlation between the mean FA values and anteroposterior diameter of the spinal canal as well as space available for the spinal cord index was demonstrated at all investigated levels. CONCLUSION: DTI is capable of revealing impairment of the cervical spinal cord microstructure at the very early stage of degenerative spine disease, even prior to spinal cord compression visible on plain MR. Anteroposterior spinal canal diameter as well as space available for the cord index is well related to spinal cord tissue integrity defined by DTI.

[Paradigm shift in the management of metastatic epidural spinal cord compression: the importance of preserving ambulation].

In 2005, a Landmark study showed that direct decompressive surgery, followed by postoperative external beam radiotherapy (EBRT) is superior to EBRT alone in patients with metastatic epidural spinal cord compression (MESCC). Patients undergoing both surgery and EBRT had similar median survival but experienced longer ambulation than with EBRT alone. Additional studies have shown improvements in quality-of-life, higher cost-effectiveness, improved pain control, and higher functional status with surgery plus EBRT. Improved neurological outcome also improved the patients' ability to undergo postoperative adjuvant therapy. According to our experience, even patients over 65 or patients with aggressive primary tumors and additional metastases have benefited from surgical intervention, living longer than expected with preservation of ambulation and sphincter control until death or shortly before. Preserving ambulation is critical. With current surgical devices and techniques, patients with MESCC who present with a single area of cord compression, back pain, neurological deficit, or progressive deformity, may benefit from surgery prior to adjuvant radiation-based treatment or chemotherapy.

Diffusion tensor imaging correlates with the clinical assessment of disease severity in cervical spondylotic myelopathy and predicts outcome following surgery.

BACKGROUND AND PURPOSE: CSM is a common neurologic disease that results in progressive disability and eventual paralysis without appropriate treatment. Imaging plays a significant role in the evaluation of CSM and has evolved with recent technical advances. We sought to systematically explore the relationship between clinical disease severity and DTI in CSM, and to investigate the potential use of DTI in surgical decision-making models. MATERIALS AND METHODS: MR imaging studies and clinical assessments were prospectively collected on 30 patients with CSM. Spearman correlations were used to investigate associations between clinical disease severity and FA at the time of diagnosis. Clinical assessment was performed using mJOA, Nurick, Short Form-36, and NDI scores. Fifteen patients with CSM subsequently underwent decompressive surgery; Spearman correlation and logistic regression were applied to this cohort to study the relationship between baseline DTI measurements and postoperative outcome. Conventional imaging (spinal cord T2 signal intensity and degree of stenosis) was evaluated for comparison with DTI. RESULTS: At diagnosis, FA demonstrated a strong correlation with baseline mJOA (r = 0.62, P < .01) and Nurick (r = -0.46, P = .01) scores. After surgery, recovery of function demonstrated by improvement in NDI score was associated with higher FA values on preoperative DTI (r = -0.61, P = .04). Severely affected patients with CSM with disproportionately high FA tended to achieve greater mJOA scores after surgery compared with subjects with lower FA (P = .08). T2 signal intensity was associated with functional status at baseline but did not predict postoperative outcome; degree of stenosis lacked any significant correlation with clinical parameters. CONCLUSIONS: DTI may be a useful diagnostic tool for assessing disease severity in CSM. The predictive value of DTI regarding postoperative outcome may improve surgical decision-making and facilitate health care outcomes research.

Assessment of cervical spondylotic myelopathy using diffusion tensor magnetic resonance imaging parameter at 3.0 tesla.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To assess spinal cord condition in patients with cervical spondylosis (CS), using diffusion tensor imaging parameter. SUMMARY OF BACKGROUND DATA: Although myelopathy is a common symptom after CS, clinically objective assessment for determination of surgical intervention is not straightforward. METHODS: Twenty-six patients with CS and 30 normal control subjects were enrolled. Diffusion tensor imaging was obtained using a single-shot fast spin-echo-based sequence at 3.0 T. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in the axial plane at 6 spinal levels. To evaluate MD and FA in patients with CS considering the normal variation at each spinal level and between spinal levels, MD and FA at the most compressed spinal level were transformed to normalized values with a z score. Presence of myelopathy was predicted with the MD and FA z scores. Diagnostic validity of MD and FA was compared with receiver operating characteristic analysis. More effective parameter and the optimal cutoff value for prediction were determined. RESULTS: In normal subjects, MD and FA were significantly different between spinal levels. In patients with myelopathy, an MD increase or an FA decrease was demonstrated in most cases. Although both an MD increase and an FA decrease had diagnostic validity for myelopathy, receiver operating characteristic analysis demonstrated a higher sensitivity and specificity for prediction of an MD increase than an FA decrease (areas under the curve for MD and FA were 0.903 and 0.760, respectively). An MD z score of 1.40 was considered to be the best diagnostic cutoff value with 100% sensitivity and 75% specificity. CONCLUSION: Myelopathy can be predicted with high accuracy with diffusion tensor imaging parameter, with the MD z score at the most compressed spinal level. LEVEL OF EVIDENCE: 3.

Surgical treatment and outcomes of metastatic breast cancer to the spine.

Metastatic vertebral body and spinal epidural lesions cause significant pain and neurological morbidity and negatively impact quality of life and survival. In instances of metastatic epidural spinal cord compression, treatment typically involves surgery and radiotherapy. The incidence of spinal metastases in breast cancer patients is high. In the light of recent improvements in survival among some patients with breast cancer, we reviewed the treatments and outcomes for patients with breast cancer who presented to our institution with metastatic epidural spinal cord compression. We identified all patients undergoing open surgery for the treatment of breast cancer metastases to the spine at our center from 1 January 2001 to 31 December 2009. We retrospectively reviewed records for the details of medical history, treatment, surgery, radiographic imaging, and follow-up. The Death Master File from the United States Social Security Administration was queried to identify the date of death where the medical record was incomplete. Outcomes were assessed by overall survival as well as preoperative and postoperative ambulatory status, bladder function, and the American Spinal Injury Association impairment classification system (ASIA). A total of 15 female patients were identified as having surgical intervention directly related to breast cancer metastasis to the spine. Most lesions (12/15) were located in the anterior vertebral column (vertebral body and/or pedicle). Two patients required re-operation, one for epidural fluid collection and one for infection. Roughly half of the patients (8/15) had well-controlled systemic disease at the time of surgery. Five patients had non-contiguous metastatic lesions elsewhere in the spine. Median survival following surgery was 1,025 days; control of systemic disease did not predict duration of postoperative survival. Seven patients had documented improvement in their ability to ambulate in the first 30 days following surgery. Bladder function was preserved in all. No patient deteriorated; and five patients had postoperative improvement of their ASIA impairment scale grade. We concluded that aggressive therapy, including surgery, is warranted for patients with symptomatic metastatic epidural spinal cord compression from breast cancer, including in the setting of advanced and progressive systemic disease.

[Updates on ossification of posterior longitudinal ligament. Ossification front of posterior longitudinal ligament and cellular biological assessment of chronic mechanical compressed spinal cord].

Mechanisms of ossification processes, pathological changes, and treatment/assessment of myelopathy symptoms because of ossification of the posterior longitudinal ligament (OPLL) remain obscure. Enchondral ossification process of OPLL was closely associated with degenerative changes of elastic fibers and cartilage formation, together with the appearance of metaplastic hypertrophic cartilage cells and neovascularization. There are differences in expression degrees of cytokines and transcription factors between mixed and localized OPLL. While the chronic compressed spinal cord may have plasticity ; the use of stem cell implants, supplementation of neurotrophic factors, in addition to surgical treatment, may bring a better clinical outcome,encouraging the development of these basic research studies. Assessment using new imaging techniques needs to determine the affected level and judge the severity of symptoms.

A re-assessment of erythropoietin as a neuroprotective agent following rat spinal cord compression or contusion injury.

This study was initiated due to an NIH "Facilities of Research--Spinal Cord Injury" contract to support independent replication of published studies that appear promising for eventual clinical testing. We repeated a study reporting the beneficial effects of recombinant human erythropoietin (rhEPO) treatment after spinal cord injury (SCI). Moderate thoracic SCI was produced by two methods: 1) compression due to placement of a modified aneurysm clip (20 g, 10 s) at the T3 spinal segment (n=45) [followed by administration of rhEPO 1000 IU/kg/IP in 1 or 3 doses (treatment groups)] and 2) contusion by means of the MASCIS impactor (n = 42) at spinal T9 (height 12.5 cm, weight 10 g) [followed by the administration of rhEPO 5000 IU/kg/IP for 7d or single dose (treatment groups)]. The use of rhEPO following moderate compressive or contusive injury of the thoracic spinal cord did not improve the locomotor behavior (BBB rating scale). Also, secondary changes (i.e. necrotic changes followed by cavitation) were not significantly improved with rhEPO therapy. With these results, although we cannot conclude that there will be no beneficial effect in different SCI models, we caution researchers that the use of rhEPO requires further investigation before implementing clinical trials.

Suspected spinal cord compression in cancer patients: a multidisciplinary risk assessment.

Investigators involved in this study sought to identify independent clinical predictors of spinal cord compression (SCC) in cancer patients by analyzing a comprehensive set of potential risk factors based on the results of spine magnetic resonance imaging (MRI). In all, the investigators analyzed 136 episodes of suspected SCC among 134 cancer patients evaluated with spine MRI. Each subject was interviewed within 7 days of the spine MRI to collect accurate self-reported symptom data. Neurologic examination data were detailed by the physician examining the subject prior to the spine MRI; uniform demographic and clinical information regarding the subject's cancer history was abstracted from the medical record. Multivariable logistic regression analysis was used to identify independent predictors of SCC. Clinically significant SCC was defined as thecal sac compression (TSC), which occurred in 50 episodes (37%). Four independent predictors of TSC were identified and included information from the neurologic examination (abnormal neurologic examination), subject-reported symptoms (middle or upper back pain), and the oncologic history (known vertebral metastases and metastatic disease at initial diagnosis). These four predictors stratified patients experiencing episodes into subgroups with varying risks of TSC, ranging from 8% (no risk factors) to 81% (three or four risk factors). These results confirmed earlier retrospective studies indicating that the evaluation of cancer patients with suspected SCC should be based upon clinical information that includes cancer-related history, symptom data,and the presence of pertinent neurologic signs. These predictors may help clinicians to assess risk in this patient population.

Development and characterization of a novel, graded model of clip compressive spinal cord injury in the mouse: Part 2. Quantitative neuroanatomical assessment and analysis of the relationships between axonal tracts, residual tissue, and locomotor recovery.

A detailed examination of the histopathological features of the clip compression injury in mice was performed to understand the relationships between neurological function and existing pathology of the spinal cord. Adult, female CD1 mice underwent three grades of extradural clip compression injury (3-g, 8-g, and 24-g FEJOTA mouse clips), transection, and sham injury at T3-4. Quantitative behavioural assessments were performed for 4 weeks following SCI. After 4 weeks, Fluoro-Gold was introduced caudal to the SCI site, at T9, and was retrogradely transported for 5 days to the origin of spared axons through the injury site. Counts of retrogradely labeled neurons in the brain-stem, midbrain, and sensory-motor cortex indicated that the number of intact descending axons that traversed the lesion decreased with increasing injury severity (F > 28; df = 4; p < 0.0001; one-way ANOVA). Independent linear correlation analyses were performed between indices of neurological recovery (BBB and IP test), counts of retrogradely labeled neurons and morphometric assessments of normal residual tissue at the injury epicenter. The BBB test correlated strongly with the amount of residual tissue at the injury epicenter (R = 0.945, df = 28, p < 0.0001). Counts of neurons retrogradely labeled with Fluoro-Gold were also strongly correlated with the BBB scores. The extrapyramidal (raphespinal, reticulospinal, vestibulospinal, and rubrospinal) tracts had Pearson correlation coefficients (R) of 0.814, 0.812, 0.813, and 0.747, respectively (df = 28, p < 0.0001). The pyramidal (corticospinal) tract had a correlation of R = 0.747, df = 28, p < 0.0001 with the BBB scores. The IP scores also correlated strongly with the persistence of extrapyramidal (raphespinal, reticulospinal, vestibulospinal and rubrospinal) tracts with correlation coefficients of 0.801, 0.782, 0.790, and 0.836, respectively (df = 28, p < 0.0001). These data indicate that the counts of retrogradely labeled neurons at the origin of distinct descending motor pathways are predictors of the variance of the functional recovery measured by the BBB and IP tests following spinal cord injury. In addition, we provide a detailed neuroanatomical study of clip compression injury in mice that can be used to study the molecular mechanisms of SCI in knockout and transgenic mice.

Dorsal root ganglia morphologic features in patients with herniation of the nucleus pulposus: assessment using magnetic resonance myelography and clinical correlation.

STUDY DESIGN: Morphologic features of the dorsal root ganglia were investigated in patients with herniation of the nucleus pulposus by means of magnetic resonance myelography. OBJECTIVES: This study was undertaken to assess morphologic changes of the dorsal root ganglia in patients with herniation of the nucleus pulposus and to determine the relations between the morphologic features of the dorsal root ganglia and clinical features. SUMMARY OF BACKGROUND DATA: It has recently been reported that application of the nucleus pulposus to a nerve root induces edema in the rat dorsal root ganglion. Edema in the human dorsal root ganglion resulting from lumbar disc herniation has not been discussed in the literature, to the authors' knowledge. METHODS: Eighty-three consecutive patients (average age 42.1 years; range 17 to 77 years) with monoradicular symptoms were examined. Dorsal root ganglion morphologic features, i.e., indentations and swelling, were evaluated by magnetic resonance myelography. The dorsal root ganglion swelling at each level was quantitatively expressed as a ratio of the dorsal root ganglion width on the involved side to that of the contralateral side and was termed dorsal root ganglion ratio. Eighty-three uninvolved levels were chosen as controls in a randomized manner. Factors possibly contributing to the morphologic changes in the dorsal root ganglion were investigated. Neurologic symptoms, evaluated by the Japan Orthopaedic Association scoring system, were correlated to the morphologic changes. The morphologic features were followed up for 1 year after treatment in a small group of patients. RESULTS: Dorsal root ganglion indentations were always found in the narrowed intervertebral foramens. The incidence of indentations was significantly higher at the involved nerve roots (10.8%) than at the uninvolved nerve roots (4.0%) (P = 0.026). Patients with dorsal root ganglion indentations were significantly older (P = 0.0008). Leg pain scores in patients with indentations were significantly poor (P = 0.007). The dorsal root ganglion ratios were significantly higher at the involved levels than at the uninvolved levels (P = 0.001); the means +/- SD were 1.19 +/- 0.25 and 1.08 +/- 0.13, respectively. Patients with lateral herniated nucleus pulposus had significantly higher dorsal root ganglion ratios than those with central herniated nucleus pulposus (P = 0.0001); the mean ratios +/- SD were 1.48 +/- 0.32 and 1.10 +/- 0.12, respectively. A moderate positive correlation was found between dorsal root ganglion ratio and age (Pearson's correlation coefficient = 0.313). There was moderate negative correlation between the dorsal root ganglion ratio and leg pain, gait, motor, and total Japan Orthopaedic Association score (correlation coefficients were = -0.385, -0.350, -0.422, and -0.358, respectively). The dorsal root ganglion ratios were significantly diminished at 1-year follow-up (P = 0.001); the means +/- SD were 1.22 +/- 0.22 and 1.09 +/- 0.07, respectively. Indentations observed before treatment disappeared after treatment. CONCLUSIONS: Swelling and impingement in the involved dorsal root ganglion were clearly visualized by magnetic resonance myelography. The swelling and indentations were well correlated with severity of leg pain. These findings have important value in understanding the pathophysiology of the nerve roots in herniated nucleus pulposus.

Spinal cord compression injury in the mouse: presentation of a model including assessment of motor dysfunction.

The purpose of this study was to develop a spinal cord injury model in the mouse. Various degrees of extradural compression were used to induce mild, moderate or severe compression injuries. Furthermore, a locomotor rating scale was developed by which the functional outcome of the spinal cord injury could be assessed. The introduction of such a model will be useful for further studies on the pathogenesis and treatment strategies of spinal cord injury. To assess hindlimb motor function, a 10-point scale was used. Initially, the animals were allowed to move freely in an open field and were rated 0-5, 0 being no movement and 5 being almost normal. Animals scoring a 5 were then assessed using steel bars with decreasing widths from 2 cm to 5 mm. For each bar successfully crossed over, they gained additional points. Before injury the hindlimb motor function score (MFS) in all the animals was 10. In mice with mild compression, MFS was decreased slightly on day 1 and recovered to 9 +/- 0.6 on day 14. For mice with moderate compression, the MFS decreased to 4.6 +/- 0.4 on day 1 after injury and gradually improved to 8.1 +/- 0.6 on day 14. Severe injury resulted in paraplegia of the hindlimbs day 1 after injury with a score of 0.6 +/- 0.2. By day 14 after injury, these animals gradually recovered to 3.9 +/- 0.1, could bear the weight on the hindlimbs and walk with a severe deficit. There was a 3%, 9% and 19% decrease in the total cross-sectional area of the spinal cord 14 days after mild, moderate and severe injury, respectively. Microtubule-associated protein immunostaining revealed that the gray matter decreased to 61 +/- 7% in moderately injured animals, while severe compression resulted in a complete loss of gray matter. White matter decreased to 86 +/- 6% in moderately injured animals and 29 +/- 11% in severely injured animals. This study shows that the mouse can be used to achieve reproducible spinal cord compression injuries of various degrees of severity. The force of the impact correlates well with the neurological and light microscopic outcome. The motor function test presented in this paper and the computerized quantification of tissue damage can be used to evaluate the efficacy of different treatment strategies.

Somatosensory evoked potential, neurological examination and magnetic resonance imaging for assessment of cervical spinal cord decompression.

The present study was designed to determine the relationship between neurological testing, anatomical imaging, and electrophysiological monitoring for assessing outcome of cervical spinal cord decompression. We prospectively studied 28 consecutive patients (age 39-76 yr) who were subjected to presurgical-(1-3 wk) and postsurgical (3-4 mo) neurological examination and recording of the median nerve somatosensory evoked potential (SEP). In 13 patients, magnetic resonance imaging (MRI) was also performed. Changes in neurological function, SEP and MRI were evaluated and graded as (1) improvement,(2) no change or (3) deterioration. Neurological outcome (NO) was based on changes in motor grade strength, sensory, reflexes and gait. The SEP outcome was based on changes in latency and disappearance of SEP waveform components whereas MRI evaluation was based on changes in spinal cord and canal diameters. Significance of association between NO, SEP and MRI was determined by Pearson's Chi-Square statistic (P<.05). The SEP improved in 71% (20/28) and deteriorated in 28% (8/28) of the subjects. An association between SEP changes and NO was found in 82% (23/28) of the subjects (P = .0038). Decompression increased the spinal canal diameter in 92% (12/13), and the spinal cord diameter in 38% (5/13) of the subjects. An association between NO, or SEP and MRI was not detected. Changes in median nerve SEP latency appear to be predictive of the neurological status of patients subjected to cervical spinal cord decompression. Postoperative increments in SEP latency or disappearance of the SEP waves were indicative of poor outcome after surgical decompression of the cervical spinal cord.

Microdecompression and uninstrumented single-level fusion for spinal canal stenosis with degenerative spondylolisthesis.

STUDY DESIGN: A retrospective review was completed on 21 patients who had a "least invasive" (one or two level) microdecompression and uninstrumented single-segment lumbar fusion for spinal canal stenosis with degenerative spondylolisthesis. OBJECTIVE: To determine whether a "least invasive" approach to lumbar spinal canal stenosis and degenerative spondylolisthesis would yield acceptable results. SUMMARY OF BACKGROUND DATA: The prevailing surgical technique for symptomatic spinal canal stenosis with degenerative spondylolisthesis is a wide midline decompression and instrumented fusion. METHODS: On an average of 38 months postoperatively, 21 patients were personally assessed on four scores: 1) their overall satisfaction with the outcome of surgery, 2) an analog back and leg pain scale, 3) a functional evaluation scale, and 4) Ferguson (upshot) anterior-posterior lumbosacral and lateral flexion-extension radiographs. RESULTS: The overall satisfactory outcome on all four scales was 16 (76%) of 21. Twenty of twenty-one patients had relief of their claudicant leg pain; the overall fusion rate was 18 (86%) of 21. Two of three patients with a pseudarthrosis had a successful outcome on the patient-oriented outcome (1, 2, and 3) scales (excluding the radiograph scale), and one was a failure. One patient with a solid fusion was a failure because of continuing back pain. One patient with a solid fusion was a failure because of continuing leg pain. The overall satisfactory outcome on the nonradiographic scales was 18 of 21, for an 86% patient satisfaction rate. CONCLUSIONS: In this retrospective study, a "least invasive" surgical approach to lumbar degenerative spondylolisthesis with spinal canal stenosis causing claudicant leg pain produced acceptable results.

Cervical cord neurapraxia: classification, pathomechanics, morbidity, and management guidelines.

One hundred ten cases of the transient neurological phenomenon, cervical cord neurapraxia (CCN), are presented. The authors established a classification system for CCN, developed a new computerized measurement technique for magnetic resonance (MR) imaging, investigated the relationship of the cervical cord to the canal, and analyzed clinical, x-ray, and MR data. One hundred nine males and one female were included in the study; the average age of the participants was 21 years (range 13-33 years). All episodes occurred during sports participation; 87% occurred while the patient was playing football. Follow-up review lasting an average of 3.3 years was available for 105 patients (95%). Narrowing of the sagittal diameter of the cervical canal in the adult spine was confirmed to be a causative factor. Cervical cord neurapraxia was not associated with permanent neurological injury and no permanent morbidity occurred in patients who returned to contact activities. Of the patients returning to contact activities, 35 (56%) experienced a recurrent episode. The risk of recurrence was increased with smaller spinal canal/vertebral body ratio (p < 0.05), smaller disc-level canal diameter (p < 0.05), and less space available for the cord (p < 0.05). There was no correlation between either the classification of the CCN episode or the disease noted on MR imaging and x-ray films and the risk of recurrence. The authors conclude that: 1) CCN is a transient neurological phenomenon and individuals with uncomplicated CCN may be permitted to return to their previous activity without an increased risk of permanent neurological injury; 2) congenital or degenerative narrowing of the sagittal diameter of the cervical canal is a causative factor; 3) the overall recurrence rate after return to play is 56%; and 4) the risk of recurrence is strongly and inversely correlated with sagittal canal diameter and it is useful in the prediction of future episodes of CCN (p < 0.001). These data will enable the physician to counsel individuals regarding a predicted risk of recurrence based on canal measurements.