Spinal cord decompression via microsurgical anterior foraminotomy for spondylotic cervical myelopathy

A microsurgical anterior foraminotomy, as a direct decompressive and motion-segment preserving technique, has been developed by the author and used successfully in many patients with spondylotic cervical radiculopathy for the past several years. From the author's increasing experience with anterior foraminotomy for cervical radiculopathy, it was noted that the spinal cord canal could be effectively decompressed utilizing the holes of anterior foraminotomy. This new technique accomplishes widening of the spinal cord canal anteriorly to the spinal cord in the transverse and longitudinal axis by direct removal of the compressive lesions through the holes of unilateral anterior foraminotomies. This technique does not require bone fusion or postoperative immobilization. 14 patients with spondylotic cervical myelopathy have been treated by this technique. 9 were males and 5 were females, and all presented with cervical myelopathy with or without radiculopathy. Age ranged from 32 to 68 years (median 55 years). 6 patients had spinal cord compression at one level, six patients experienced it at two levels, and two patients had it at three levels. Postoperatively, all patients showed improvement in their myelopathic symptomatology as well as gaining relief of their radicular symptoms. Corresponding MR scans confirmed satisfactory anatomical decompression in all patients. Postoperative dynamic roentgenograms confirmed spinal stability in all patients as well. Patients stayed in the hospital overnight postoperatively, and cervical braces were not used. This new surgical technique has shown excellent clinical outcomes with fast recovery and adequate anatomical decompression in 14 patients with spondylotic cervical myelopathy.     

An autopsy case of an extensive epidural spinal abscess demonstrating necrotizing poliomyelopathy

A 59-year-old man with a history of diabetes mellitus (NIDDM) presented with fever, back pain and weakness in the left lower limb. Three weeks later he suddenly developed flaccid paraklegia, a sensory deficit below the abdomen and sphincter dysfunction. MR images of the spinal cord showed an extensive anterior spinal epidural abscess extending from the seventh cervical to the twelfth thoracic spine and osteomyelitis in the lower thoracic spines. He died of pulmonary infection one year after the disease onset. Postmortem examination revealed a large empyema in the lung. On neuropathological examination, small multiple hemorrhagic or ischemic lesions were found in the basal ganglia and the pons. The spinal cord was markedly atrophic in the lumbar cord. However, there was neither compression deformity in the cord nor occlusion in the anterior spinal artery. Throughout the thoracic cord, rarefaction and focal cavity formation was selectively present in the gray matter, particularly the posterior horns. In the white matter, vacuolar changes were seen peripherally as well as Wallerian degeneration in the lateral and anterior corticospiral tracts and in the fascicles gracilis bilaterally. The mechanisms inducing the cord damage in cases of epidural spinal abscess have been speculated to be either direct compression by the abscess or the secondary circulatory disturbance in the cord due to compression. In our case, the cord showed necrotizing poliomyelopathy, which was similar to that of ischemic myelopathy found in the cases of cardiac arrest or dissecting aneurysm of the aorta. Autopsy study of spinal cord lesion associated with epidural abscess has been limited in number and our case should contribute to the understanding of the pathomechanism of such myelopathy.     

Magnetic resonance imaging study on the results of surgery for cervical compression myelopathy

The morphologic changes and signal intensity of the spinal cord on preoperative magnetic resonance images were correlated with postoperative outcomes in 74 patients undergoing decompressive cervical surgery for compressive myelopathy. The transverse area of the spinal cord on T1-weighted images at the level of maximum compression was closely correlated with the severity of myelopathy, duration of disease, and recovery rate as determined by the Japanese Orthopaedic Association score. In patients with ossification of the posterior longitudinal ligament or cervical spondylotic myelopathy, the increased intramedullary T2-weighted magnetic resonance imaging signal at the site of maximal cord compression and duration of disease significantly influenced the rate of recovery. A multiple regression equation was then developed with these three variables to predict surgical outcomes.     

Cervical spondylotic myelopathy: surgical results and factors affecting prognosis

OBJECTIVE: A variety of factors may affect surgical outcome in patients with cervical spondylotic myelopathy. The aim of this study is to determine these factors on the basis of preoperative radiological and clinical data. METHODS: To assess the factors affecting postoperative outcome after surgery for cervical spondylotic myelopathy, the clinical and radiological data of 27 patients with cervical spondylotic myelopathy were reviewed. Functional and neurological statuses were assessed using the Japanese Orthopaedic Association (JOA) scale modified by Benzel. In all patients, the effect of age, symptom duration, cervical curvature, presence or absence of preoperative high signal intensity within the spinal cord as revealed by T2-weighted magnetic resonance imaging, and diameters of the spinal canal and vertebral body on pre- and postoperative neurological statuses were investigated. Plain radiographs were obtained for all patients, magnetic resonance images for 21 patients (77.8%), computed tomographic scans for 13 patients (48.1%), myelograms for 6 patients (22.2%), and computed tomographic myelograms for 4 patients (14.8%). There were five patients with a JOA score of 10, six patients with a JOA score of 11, six patients with a JOA score of 12, four patients with a JOA score of 13, four patients with a JOA score of 14, one patient with a JOA score of 15, and one patient with a JOA score of 16. All patients underwent cervical laminectomies. The mean follow-up period was 54.1 months. The final neurological examinations revealed improvement in the JOA scores of 85.1 % of the patients. RESULTS: Statistical analysis of all patients revealed mean JOA scores of 12.185 +/- 1.618 and 14.370 +/- 2.15 before surgery and at final examination, respectively. The difference between the preoperative JOA score and the final JOA score was determined to be statistically significant (P < 0.0001). Statistical analyses also showed better neurological improvement in patients younger than 60 years and in patients with normal preoperative cervical lordosis. Although patients without preoperative high signal intensity of the spinal cord showed a better improvement rate than did patients with preoperative high signal intensity, the determined difference was statistically insignificant. CONCLUSION: It can be concluded that age and abnormal cervical curvature predict less postoperative neurological improvement. The presence of preoperative high signal intensity within the spinal cord may also reflect less neurological improvement.     

Neuroimaging and pathology of the spinal cord in compressive cervical myelopathy

Magnetic resonance imaging (MRI) has enabled us to see the spinal intramedullary pathology as differences in signal intensity. Intramedullary high intensity lesions were observed on T2-weighted MRI in patients with cervical spondylotic myelopathy (20.0%) and ossification of the posterior longitudinal ligament (OPLL) of the cervical spine (25.7%). The frequency of this findings was proportional to the clinical severity of myelopathy and degree of spinal cord compression. The pathophysiological basis of such signal abnormality was presumed to vary from acute edema to chronic myelomalacia. The intramedullary lesion on MRI is considered to be the main site of lesion responsible for the neurological symptom because of a good correlation between the neurological level and high intensity level. We found from nine autopsy cases of OPLL that there are distinct differences in severity and extent of pathological changes between the spinal cord with a boomerang-shaped cross-section and that with a triangular-shaped cross-section. In the boomerang-shaped cases, major pathological changes were restricted to the gray matter and the white matter was relatively well preserved. Secondary wallerian degeneration was restricted to the fasciclus cuneatus the fibers of which were derived from the affected segments. In the cases of a triangular shape, pathological changes were more severe, both white and gray matter were involved. There were severe pathological changes over more than one segment, and both descending degeneration of the lateral pyramidal tracts and ascending degeneration of the posterior column, including the fasciclus gracilis, were observed. In conclusion, it is clinically very important to understand the pathological basis of the compressed spinal cord on neuroimages.     

Ki-67 and apoptosis in a embryologic model

A 67-year-old man developed slowly progressive muscular weakness in the bilateral upper extremities (C5- 7 regions) without signs of sensory deficit following the cervical radiation therapy (70.5Gy) for right laryngeal cancer 4 years before. These clinical signs resembled those of lower motor neuron disease. MRI with gadolinium-DTPA, however, showed enhancement in the bilateral C5 and C6 anterior roots, suggesting the cervical radiculopathy due to radiotherapy. It is known that radiation to the spinal cord can lead to "selective anterior horn cell injury". This is the first case report of the cervical radiation radiculopathy, which, if without MRI, might be classified into selective anterior horn cell injury. Suggestion is made for the hypothesis that the spinal motoneuron loss in radiation myelopathy would be caused by retrograde degeneration due to anterior root damages.     

Tetraparesis following dental extraction: case report and discussion of preventive measures for cervical spinal hyperextension injury

This concerns a patient with compression myelopathy following passive hyperextension of the cervical spine during a dental procedure. Although he had been asymptomatic prior to the procedure, subsequent cervical spinal imaging revealed advanced spondylosis and spinal stenosis. Spinal stenosis is often asymptomatic for a long time. However, when radiculomyelopathy occurs after minor trauma to the head or neck, the patient is often found to have spinal stenosis. Specifically, hyperextension of a cervical spine with spondylotic changes can lead to compression myelopathy. Acquired spinal stenosis correlates positively with aging. As the size of the elderly population continues to increase the prevalence of cervical spondylotic radiculo-myelopathy will likely increase as well. Since appropriate precautions against potential neurologic damage can be undertaken, we suggest radiographic screening for pre-existing spinal stenosis prior to a procedure requiring hyperextension of the neck. Preventive measures for individuals with asymptomatic spondylotic changes and education of all health-care professionals to avoid abrupt or prolonged hyperextension of the cervical spine is emphasized.     

Spontaneous thoracic spinal cord herniation. A case report

STUDY DESIGN: This is a case report. OBJECTIVE: To focus attention on spontaneous spinal cord herniation as a rare cause of myelopathy that can be diagnosed preoperatively and can be corrected surgically. SUMMARY OF BACKGROUND DATA: A 34-year-old woman presented with spastic paraparesis. Magnetic resonance imaging scan of the thoracic spine revealed anterior displacement and tethering of the cord at T6-T7 and a dorsal intradural arachnoid cyst. Excision of the cyst was performed without improvement in symptomatology. During reoperation the thoracic spinal cord hernia was discovered and was reduced intradurally. METHODS: The authors describe the clinical, radiographic, and surgical findings of this patient and review the findings from other reported cases. They discuss the proposed theories for the pathophysiology of the cord herniation and the surgical management. RESULTS: The patient had idiopathic thoracic spinal cord herniation as there was no history of previous spine surgery or injury. The authors believe that the cord herniated through a congenital dural defect, which resulted in the development of a pseudoarachnoid cyst dorsally to the hernia. The patient improved after intradural reduction of the hernia and closure of the dural defect. CONCLUSION: Idiopathic spinal cord herniation should be recognized as a cause of progressive myelopathy that can be managed successfully with microsurgical techniques.     

Clinical experience with early enteral feeding in very-low-birth-weight infants

We investigated dorsal shift and anteroposterior spinal cord diameter after expansive open-door laminoplasty, comparing pre- and postoperative computed tomographic myelographic images to clarify the relationships between surgical outcome and these changes. Dorsal shift occurred at the midcervical spine in cervical spondylotic myelopathy (CSM) but was less extensive in ossification of the posterior longitudinal ligament (OPLL). Spinal cord anteroposterior diameter expanded for OPLL but did not for CSM. Correlation of outcome and dorsal shift was not significant for OPLL or CSM. Correlation of outcome and expansion was significant for OPLL, but not for CSM.     

Cervical spine osteoarthritis

Cervical spine is particularly susceptible to anatomical osteoarthritis, but in a good half cases it remains asymptomatic. Painful cervical spine osteoarthritis results in neck pain, sometimes acute, more commonly chronic. But cervical osteoarthritis may induce compression of the neurovascular structures contained into the cervical spine: upper arm nerve root pain by nerve root compression; myelopathy by spinal cord compression; sometimes vertebro-basilar insufficiency by compression of vertebral arteries.     

Nucleotide sequence of alkyl-dihydroxyacetonephosphate synthase cDNA from Dictyostelium discoideum

OBJECTIVE AND IMPORTANCE: Congenital anomalies of the posterior arch of the atlas (C1) are uncommon. They range from partial clefts to total agenesis of the posterior arch. Developmental cervical canal stenosis is a congenital anomaly that may cause cervical myelopathy. Myelopathy caused by cervical stenosis at the level of the atlas has been reported in only three cases. We present two cases of nontraumatic cervical myelopathy caused by spinal stenosis at the level of the atlas associated with a hypoplastic but complete posterior arch of C1. CLINICAL PRESENTATION: Two elderly Chinese men developed cervical myelopathy gradually during months to years, without preceding trauma. Imaging revealed a hypoplastic but complete posterior C1 arch associated with changes of spondylosis in both patients, producing severe spinal stenosis and spinal cord compression. Posterior decompression was achieved in both by the removal of the posterior arch of C1 with its surrounding thickened posterior ligaments. Symptoms and clinical findings improved in the two patients during the follow-up period. CONCLUSION: The anomaly presented in our two cases differs from the established classification of congenital abnormalities of the posterior arch of the atlas, suggesting a different embryological defect. The hypoplastic posterior C1 arch created a congenitally narrowed spinal canal in our patients, rendering the spinal cord more susceptible to compression related to degenerative changes of the spine. Surgical removal of the shortened posterior C1 arch and surrounding degenerative ligaments is an effective treatment for symptomatic patients with this condition.     

Magnetic resonance imaging in cervical spinal cord compression

In patients with cervical spondylotic myelopathy MRI sometimes shows increased signal intensity zones on the T2-weighted images. It has been suggested that these findings carry prognostic significance. We studied 56 subjects with cervical spinal cord compression. Twelve patients showed an increased signal intensity (21.4%) and a prevalence of narrowing of the AP-diameter (62% vs 24%). Furthermore, in this group, there was evidence of a longer mean duration of the symptoms and, in most of the patients, of more serious clinical conditions. The importance of these predisposing factors remains, however, to be clarified since they are also present in some patients without the increased signal intensity.     

Anterior cervical corpectomy for cervical spondylotic myelopathy

OBJECTIVE: To evaluate the efficacy of anterior surgery for the treatment of cervical spondylotic myelopathy, we have reviewed our experience with anterior cervical corpectomy (ACC) at the University of Florida, specifically analyzing neurological outcomes and complications. These results have been compared with historical control subjects receiving laminectomy or "no treatment." METHODS: Between 1982 and 1992, 93 ACC operations were performed for the primary diagnosis of cervical spondylotic myelopathy. This consecutive series of patients was reviewed retrospectively. Age, gender, pre- and postoperative myelopathy severity, number of levels decompressed, and neurological complications were assessed. Myelopathy severity was graded using the Nurick myelopathy grading system. The average follow-up period was 39 months (range, 2-137 mo). RESULTS: Symptomatic improvement was achieved for 92% of patients (F = 28.9, df = 2172, P < 0.001). Nurick scores reflected improvement for 86% of patients, with the conditions of 13% remaining unchanged and only one patient showing worsening. Preoperative myelopathy severity was weakly correlated with age (P < 0.05) but was not correlated with gender or number of levels decompressed. Similarly, postoperative myelopathy severity was not significantly correlated with age, gender, preoperative myelopathy severity, or number of levels decompressed. ACC-treated patients showed an average improvement of 1.24 points on the Nurick scale, compared with an improvement of 0.07 points for patients treated with laminectomy (P < 0.001) and a deterioration of 0.23 points for patients undergoing conservative treatment (P < 0.001). Complications were slightly more likely to occur in older patients (P < 0.05). The number of levels decompressed was not significantly correlated with complications. Only one permanent neurological complication was seen in this series of patients. CONCLUSION: We conclude that ACC is a safe and effective treatment for cervical spondylotic myelopathy. In an average of 39 months, ACC showed improved results in terms of myelopathy scores, compared with historical control subjects receiving either no treatment or laminectomy. Age, gender, preoperative myelopathy severity, and extent of disease were not negative predictors of clinical outcomes.     

Ultrasonographic examination of the ovine thorax

STUDY DESIGN: An experimental immunohistochemical investigation using an antibody for proliferating cell nuclear antigen. Surgically-extirpated specimens of posterior longitudinal ligament tissues from patients with hypertrophy of the posterior longitudinal ligament and other disorders of the cervical spine were analyzed. OBJECTIVE: To analyze the developmental mechanism of hypertrophy of the posterior longitudinal ligament, the authors evaluated the growth activity of cells in the posterior longitudinal ligament tissues by examining the immunolocalization of the proliferating cell nuclear antigen. SUMMARY OF BACKGROUND DATA: Although a number of cases of hypertrophy of the posterior longitudinal ligament have been reported, the pathophysiology of ligament hypertrophy is still unclear. It is well established that the proliferating cell nuclear antigen is a cell proliferation marker, and immunohistochemical analysis using an anti-proliferating cell nuclear antigen antibody is of value in assessing the cell growth activity of several tissues. METHODS: During anterior decompression surgery in the cervical spine, the authors extirpated posterior longitudinal ligament tissues in one piece from patients with hypertrophy of the posterior longitudinal ligament, ossification of the posterior longitudinal ligament, cervical disc herniation, and cervical spondylotic myelopathy. Midsagittal sections of the specimens were stained with an antibody against the proliferating cell nuclear antigen. RESULTS: In cases of hypertrophy of the posterior longitudinal ligament, immunostaining with the proliferating cell nuclear antigen was detected in cells in the posterior longitudinal ligament, not only at the vertebral endplate level, but also at the midvertebral level. A similar distribution of proliferating cell nuclear antigen-positive cells was observed in cases of ossification of the posterior longitudinal ligament. In cases of cervical disc herniation, however, proliferating cell nuclear antigen-positive cells in posterior longitudinal ligament tissues were restricted to the vertebral endplate level. No immunostaining with the proliferating cell nuclear antigen was seen in posterior longitudinal ligament tissues in cases of cervical spondylotic myelopathy. CONCLUSIONS: Cell growth activity was accelerated in posterior longitudinal ligament tissues in cases of hypertrophy of the posterior longitudinal ligament; such an unusual phenotype of posterior longitudinal ligament cells was also expressed in cases of ossification of cervical disc herniation and cervical spondylotic myelopathy. Therefore, up-regulation of the growth of posterior longitudinal ligament cells may contribute to the development of hypertrophy of the posterior longitudinal ligament, and some common regulatory mechanism(s) on the proliferation of posterior longitudinal ligament cells seem to underlie the development of hypertrophy of the posterior longitudinal ligament and ossification of the posterior longitudinal ligament.     

Apoptosis as a mechanism of neuronal cell death following acute experimental spinal cord injury

The complex biochemical interactions following acute spinal cord injury have undergone considerable investigation recently. Progress has been made in discovering both primary and secondary injury cascades that combine to produce the ultimate neurologic insult. Traditionally, neuronal and supporting cell death following spinal cord injury have focused on necrotic death pathways resulting passively from the actual mechanical tissue damage and inflammatory processes which follow. However, the occurrence of programmed apoptotic cell death which is an actively mediated cellular process may occur following acute spinal cord injury and, if present, may play a role in the ultimate neurologic insult. In this study, we document a chronologically-specific course of apoptotic cell death by the TUNEL assay technique following an acute experimental spinal cord injury in the rat model. In this manner, apoptotic cell death following acute spinal cord injury may play a pivotal role in the secondary injury cascade which produces the ultimate neurologic insult and may allow potential for mediating neuronal survival via anti-apoptotic factors such as the protooncogene Bcl-2.     

Myelopathy after intrathecal chemotherapy. A case report with unique magnetic resonance imaging changes

BACKGROUND: Paraplegia caused by intrathecal chemotherapy has no known pathognomonic features and is a diagnosis of exclusion. METHODS: The authors reported the clinical and neuroimaging findings in one patient with this syndrome. RESULTS: The patient had severe paraplegia with urinary retention and impaired pain and touch sensation below T-10 with sparing of proprioception and vibration sense. Magnetic resonance imaging (MRI) scan showed diminished intensity throughout the central cervical spinal cord. Post-gadopentetate dimeglumine enhancement was scattered throughout the cervical spinal cord and in two areas of the dorsal spinal cord. Axial views of the cervical spinal cord showed that this enhancement was limited to the lateral columns. CONCLUSIONS: The MRI in myelopathy due to intrathecal chemotherapy may show a unique pattern of postgadopentetate dimeglumine enhancement limited to the lateral columns of the spinal cord. However, two recently encountered patients with the same syndrome did not show similar changes.     

Clinical and technical assessment of the cervical spine

In analysis of the cervical and cervicobrachial syndrome with or without signs of compression of the nerve root or spinal cord, functional assessment of the cervical spine is of great importance. Comparisons between actively performed and passively induced motion can be verified by using standardized computer-assisted assessment allowing precise documentation of the range of motion and coupled motion. The age-related normal values should be considered. The neurological assessment includes not only the cranial nerves and upper extremities but also lower extremities to avoid overlooking the signs of cervical myelopathy. In patients with compression of nerve roots or the spinal cord neurophysiology might be helpful in identifying or verifying compression. In patients with suspected myelopathy sensory evoked potentials will allow assessment of the function of the ascending spinal pathways and motor evoked potentials, assessment of the function of the descending cortical spinal pathways.     

The effect of intraspinal cytosine arabinoside on the re-irradiation tolerance of the cervical spinal cord of young and adult rats

Intrathecal treatment with cytosine arabinoside (ara-C) in combination with radiation has been used as prophylactic treatment in children with acute lymphatic leukaemia. Animal experiments have shown that ara-C enhances the effect of radiation on the spinal cord when administered shortly before irradiation, and that the long-term recovery after a combined treatment may be impaired. In the present experiments immature, 3-week-old rats, were treated with ara-C and radiation on the cervical spinal cord, and the long-term recovery was examined by reirradiation after different intervals. The endpoint of the study was paresis due to radiation myelopathy. The results showed a clear enhancement of the radiation effect with a dose-modifying factor of 1.2, when ara-C was administered before irradiation. However, no indications for impaired long-term recovery were observed. Additional experiments in adult rats with ara-C treatments during a 6-month interval between two radiation doses also did not suggest any interference between ara-C treatment and long-term recovery of radiation induced injury. It is concluded that for both the adult and immature nervous tissue, only when ara-C is administered intraspinally shortly before irradiation, interaction between ara-C and radiation results in a significant reduction of the isoeffective radiation dose by a factor of 1.2 (1.13-1.37, 95% confidence interval).     

Morphometric study of myelinated fibers in human cervical spinal cord white matter

STUDY DESIGN: Using human autopsy spinal cord specimens, morphologic measurements of myelinated nerve fibers were performed, focusing on the regions that include the main white matter conduction paths. The hemilateral spinal cord morphology was also measured, and its relation with the component myelinated nerve fibers determined. OBJECTIVES: To determine the relation between spinal cord transverse area in the normal lower cervical spine, the site most vulnerable to chronic compressive myelopathy, and myelinated nerve fibers. SUMMARY OF BACKGROUND DATA: Considerable interindividual variation normally is observed in the morphology of the spinal cord transverse area. The influence of this variation on the composition of the white matter myelinated nerve fibers is obscure. METHODS: The C7 segments from seven cadavers were resected, and from magnified photographs of paraffin-embedded specimens, the hemilateral spinal cord area and funicular area were measured. Nerve fiber morphology was measured using Epon-embedded specimens. Three regions that included the main conduction paths were sampled, and magnified photographs obtained. The nerve fiber transverse morphology was measured using the ellipse conversion method, and the myelinated nerve density and fiber area were determined. RESULTS: Marked interindividual variations were found in both the hemilateral spinal cord transverse area and funicular area. A positive correlation was noted between the two, with the spinal cord transverse area large in the cases with a large funicular area. For fiber density and area, histograms were constructed that showed characteristic distribution patterns in each region. By dividing each region into two components (i.e., small- and large-diameter fibers), it was found that the interindividual variation in large-diameter fiber density was small, clarifying that the absolute number of large-diameter fibers compared to fiber density is more strongly dependent on the funicular area. CONCLUSIONS: The absolute number of large-diameter myelinated fibers is smaller in cross-sections of thin as compared to those of thick spinal cord. When elucidating the pathophysiology of compressive myelopathy, it is necessary to study not only the circumstances surrounding the spinal cord, but this kind of factor intrinsic to the spinal cord itself.