Anteroposterior Diameter Of Spinal Canal Research Articles

Do the cervical spinal canal dimensions predict pre-myelopathic changes of cervical spinal cord? - a magnetic resonance image study

Abstract Background and aims: The cervical region is the most mobile portion of the spinal column and it is here that the earliest disc degenerations are encountered. Hence it is of great interest to neurologists and neurosurgeons. Degenerative arthritic changes in the cervical spine secondary to ageing may result in bony and soft tissue overgrowth causing encroachment on the cervical spinal canal resulting in cervical canal stenosis. This may predispose to compressive myelopathy. The study aims to determine the predictability of myelopathy based on the dimensions of spinal canal at the cervical region. Materials and methods: The study included 600 patients who underwent MRI scan of cervical spine in the Department of Imaging Sciences and Interventional Radiology, Sree Chithra Thirunal Institute of Medical Sciences and Technology, Thiruvananthapuram, Kerala. It included patients of different age groups of both sexes who were classified into six groups. T1 weighted axial images were obtained using spin echo sequence. The axial slices were made at the mid vertebral levels from C2-C7 vertebrae. The anteroposterior diameters of spinal canal in axial images at mid cervical vertebral levels from C2-C7 were measured. Analysis of data was done by mean, standard deviation, independent sample t test, ANOVA and Chi­ square test. Results: The mean anteroposterior diameter of the canal at different cervical vertebral levels decreases as age advances. Tbe premyelopathic changes were more in males which may be attributed to change in canal shape. Conclusion: Cervical spinal canal dimensions are useful to predict premyelopathic changes of cervical spinal cord.

Incidence and Risk Factors for Late Neurologic Deterioration after C3-C6 Laminoplasty for Cervical Spondylotic Myelopathy.

Study Design Retrospective study. Objective We previously reported that the long-term neurologic outcomes of C3–C6 laminoplasty for cervical spondylotic myelopathy (CSM) are satisfactory, with reduced frequencies of postoperative axial neck pain and kyphotic deformity. However, only 20 patients were included, which is a limitation in that study. The present study investigated the incidence of late neurologic deterioration (LND) of myelopathic symptoms after C3–C6 laminoplasty for CSM and attempted to identify significant risk factors for LND in a larger patient population. Methods Subjects comprised 137 consecutive patients with CSM who underwent C3–C6 laminoplasty (bilateral open-door laminoplasty, n = 85; unilateral open-door laminoplasty, n = 52) and were followed for >24 months (mean follow-up, 70 months; range, 25 to 124 months). The patients' medical records were examined for evidence of LND due to cervical myelopathy. The age at time of surgery, sex, surgical procedures, anteroposterior spinal canal diameter at the C7 level, type of C6 spinous process, pre- and postoperative C2–C7 angle, C3–C6 range of motion (ROM), and disk height at the C6–C7 level were analyzed to identify risk factors for LND. Results Three patients (2.2%) developed LND of myelopathic symptoms due to caudal segment pathology adjacent to the C3–C6 laminoplasty (LND group). In these three patients, mean Japanese Orthopaedic Association (JOA) score improved from 10.2 before surgery to 12.2 at the time of maximum recovery, and declined to 9.7 just before additional surgery. On the other hand, in 134 patients without LND (non-LND group), the mean JOA score significantly improved from 10.2 before surgery to 13.4 at the time of maximum recovery and was maintained by the final follow-up (13.2). Compared with the non-LND group, the LND group showed significantly smaller anteroposterior spinal canal diameter at C7, more restricted postoperative C3–C6 ROM, and greater postoperative decrease in disk height at C6–C7, although a logistic regression analysis showed no significant differences. Conclusions In patients with CSM with more severe developmental spinal canal stenosis at C7, accelerated degeneration at the caudal segment resulting from restricted C3–C6 ROM after C3–C6 laminoplasty might lead to LND.

A diagnostic study of thoracic myelopathy due to ossification of ligamentum flavum.

We set out to establish a magnetic resonance imaging (MRI) and computed tomography (CT)-based diagnostic method for determining the responsible segments in thoracic myelopathy due to ossification of the ligamentum flavum (OLF). Forty-four patients who underwent surgery for treatment of myelopathy due to OLF between June 2005 and May 2013 were enrolled in this study as the myelopathy group. Forty-four patients who were identified through CT and MRI scans to have OLF but had no definite neurologic deficits prior to the examination were included as the control group. MRI and CT examination were reviewed, and the degree of spinal canal compromise was graded on axial T2-weighted MRI. Anteroposterior spinal canal diameter was measured at the maximally stenosed level on axial and sagittal CT. The canal grade and the cross-section area-occupying ratio were measured and calculated on the CT scans. The diagnostic coincidence rates for the indices were then compared. Cases of Grade IV were all in the myelopathy group while cases of Grade II were all in the control group. The canal grade (paramedian) was the most relevant continuous variable with the largest JOA score (r = 0.685, P < 0.005). A canal grade (paramedian) of <60% can be used as a critical value for determining OLF-induced myelopathy (sensitivity and specificity, 95.5%). Spinal canal compromise is relevant to spinal cord deficits in patients with OLF, and a canal grade (paramedian) can be used to quantify spinal cord deficits. Additionally, a canal grade (paramedian) of <60% on axial CT scan can serve as a critical value for diagnosing OLF-induced myelopathy, especially for Grade III compression on T2-weighted MRI.

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

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. 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. 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. 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.

Osteological study of lumbar vertebrae in Western Maharashtra population

Introduction: Anatomical studies have been conducted in different ethnic groups to measure the bony vertebral dimensions and to determine the normal limits which will serve as guidelines in assessing lumbar stenosis. Aim: To determine the normal range of measurements of lumbar vertebrae in Western Maharashtra population. Materials and methods: Various dimensions of lumbar vertebrae from L1 to L5 were measured in 420 lumbar vertebrae, collected from the Department of Anatomy, Government Medical College, Miraj, and other Medical colleges of Western Maharashtra. Results and discussion: Mean transverse diameter of vertebral body as well as of spinal canal and anteroposterior diameter of vertebral body were minimum at L1 and maximum at L5. The mean anteroposterior diameter of spinal canal showed a gradual decrease from L1 to L5 in both sexes. Making use of the above parameters, the canal body ratio and spinal index of Jones were calculated. These parameters were also compared with those of previous studies. Similarly, from the above parameters, the values suggestive of lumbar canal stenosis and intraspinal tumor were calculated. Conclusion: The present study shows regional and ethnic variation in the parameters of lumbar vertebrae, thus emphasizing the need to determine the normal range of values for different populations.

Long-term Results of Expansive Open-Door Laminoplasty for Cervical Myelopathy−Average 14-Year Follow-up Study

Retrospective case series on long-term follow-up results of original expansive open-door laminoplasty for cervical myelopathy due to cervical spondylosis (CSM) and ossification of posterior longitudinal ligament (OPLL). To elucidate efficacy and problems of original open-door laminoplasty to improve future surgical outcomes. Little information is available on long-term outcomes of original open-door laminoplasty without grafts, implants, or instruments. The study group included 80 patients who underwent original open-door laminoplasty and were followed for minimum 10 years. Clinical results, including Japanese Orthopedic Association scores, recovery rates, occurrences of complications, and long-term deterioration were investigated. Cervical alignments, type of OPLL, cervical range of motion, anteroposterior diameter of spinal canal, and progression of OPLL were assessed on plain radiographs. Spinal cord decompression was verified on magnetic resonance imaging. Average Japanese Orthopedic Association score and recovery rate improved significantly until 3 years after surgery and remained at an acceptable level in both cervical spondylosis and OPLL patients with slight deterioration after 5 years. Segmental motor palsy developed in 8 patients. Late deterioration, mainly lower extremity motor score decline, developed in 8 CSM and 16 OPLL patients. Overall cervical range of motion decreased by 36%. Patients with cervical lordosis decreased gradually in both patient groups. Such changes in alignments did not affect surgical results in CSM patients, while OPLL patients with preoperative kyphosis had lower recovery rates than those with straight and lordotic alignments. OPLL progression that was detected in 66% of patients did not affect clinical results. Although infrequent, magnetic resonance imaging revealed atrophy of spinal cord, spinal cord compression at adjacent segments due to degenerative changes and OPLL progression. Long-term results of open-door laminoplasty without bone graft, graft substitutes, or instruments were satisfactory. However, segmental motor paralysis, kyphosis, established before and after surgery, OPLL progression, and late deterioration due to age-related degeneration remain challenging problems.

A Cadaveric Examination of Pediatric Cervical Pedicle Morphology

A retrospective radiographic analysis of 47 intact cadaver pediatric cervical spines at the Hamann-Todd Osteology Collection in Cleveland, Ohio. Evaluate the morphology of the pediatric cervical spine pedicle, the feasibility of surgical pedicle screw instrumentation, and examine the contribution of growth to the pedicle axis. The adult cervical spine has been studied extensively and the morphology of the pedicles well documented. The morphology of the pediatric cervical, thoracic, and thoracolumbar spine has been studied radiographically, but, to our knowledge, no study has specifically examined the cervical spine pedicle, pedicle axis, and their changes with growth. A total of 47 pediatric human cadaver spines with a mean age of 13 years (range 3-18 years at death) from the Hamann-Todd Osteology Collection at the Cleveland Museum of Natural History were analyzed radiographically. There were 25 females and 22 males. The C3-C7 vertebrae were used in this study. The 228 vertebral specimens were evaluated in the axial and sagittal planes. The radiographs were subsequently digitized and measured for 5 parameters on the axial view: pedicle axis length, pedicle length, pedicle width, cervical spinal canal anteroposterior spinal canal diameter, and interpedicular distance. The pedicle axis length increased with advancing age. The pedicle length remained relatively constant throughout growth, and the pedicle diameter showed a statistically significant increase with growth. Mean pedicle diameter width was 3.0 mm at C3 and 4.2 mm at C7 in the 3-5 year-old group compared to 4.3 mm and 6.1 mm, respectively, at C3 and C7 at 18 years of age. The anteroposterior spinal canal diameter remained relatively constant with increasing age. The interpedicular distance achieved 80% of its adult size by 3-5 years of age. Regarding pedicle axis growth, the 3 components of the pedicle axis (i.e., vertebral body, pedicle, and lateral mass) were analyzed with regards to their contribution to growth. The vertebral body contributed an increasing percentage to overall pedicle axis growth with age, while the pedicle itself contributed a progressively smaller percentage. Our results showed an overall increase in the pedicle axis and pedicle width but no significant change in pedicle length. The data in this study indicate that pedicle screws may not be safe for use in the pediatric cervical spine, particularly younger children. The use of lateral mass screws was not specifically addressed in this study. As in the thoracolumbar spine, growth of the pedicles in relation to the spinal canal is lateral to the canal. The vertebral body itself appears to contribute most to overall pedicle axis growth, while the pedicle itself contributes a progressively smaller percentage over time.

Adjacent segment disease after anterior cervical interbody fusion

Background context There have been many follow-up studies on anterior interbody fusion for cervical nerve root and spinal cord compression, and excellent neurological outcomes have been reported. However, postoperative degenerative changes at adjacent discs may lead to the development of new radiculopathy or myelopathy. In the previous reports, the incidence of symptomatic adjacent segment disease has ranged from 7% to 15%. Purpose The present study was undertaken to investigate the incidence of symptomatic adjacent segment disease after anterior cervical interbody fusion (ACIF) and to identify the factors that are related to the development of this disease. Study design/setting This is a retrospective cohort study. Patient sample A total of 112 patients were followed up clinically and radiologically for more than 2 years. Outcome measures Follow-up evaluation was primarily by means of clinical visits. The postoperative course of any symptoms, the findings of neurological examination and serial follow-up radiographs were performed in all patients. Methods The diagnosis of symptomatic adjacent segment disease was based on the presence of new radiculopathy or myelopathy symptoms referable to an adjacent level, and the presence of a compressive lesion at an adjacent level by magnetic resonance imaging or myelography. We evaluated the correlation between the incidence of symptomatic adjacent segment disease and the following clinical parameters (age at operation, sex, number of the levels fused) and radiological parameters (preoperative cervical spine alignment, preoperative range of motion of C2–C7 cervical spine, anteroposterior spinal canal diameter, preoperative existence of an adjacent segment degeneration on plain radiograph, myelography and magnetic resonance imaging [MRI]). Results Symptomatic adjacent segment disease developed in 19 of 112 patients (19%) followed. A Kaplan-Meier survival analysis was performed in order to follow the disease-free survival of the entire series of patients. The disease-free survival rates were 89% at 5 years, 84% at 10 years and 67% at 17 years. The incidences of indentation of dura matter on preoperative myelography or disc protrusion on MRI at the adjacent level were significantly higher in disease cases (p=.0087, .0299, respectively; chi-squared test). However, the other parameters did not show a statistically significant difference. There were seven cases (37%) who had failure of nonoperative treatment and additional operations were performed. Conclusions The incidence of symptomatic adjacent segment disease after ACIF was higher when preoperative myelography or MRI revealed asymptomatic disc degeneration at that level regardless of the number of the levels fused, preoperative alignment, spinal canal diameter or fusion alignment.

頚部脊柱管狭窄症のＸ線学的評価 身長との関係について

This study evaluated the relationship beween spinal canal anteroposterior diameter, canal-body ratio and height. Subjects consisted of 50 patients with cervical spondvlotic myelopathy, and a control group of 50 healthy male volunteers. The anteroposterior dimensions of the vertebral bodies and spinal canal were assessed on lateral roentgenograms, using a target distance of 150cm. The width of the canal was measured between the midpoint of the posterior cortex of the vertebral body to the closest point on the spinolaminar line. The width of the vetebral body was measured at its center.Results revealed that the spinal canal anteroposterior diameter was narrower in the cervical spondylotic myelopathy group compared to the control group. In contrast there was no significant difference between the 2 groups in regard to vertebral body anteroposterior diameter. A correlation between anteroposterior dimensions of the vertebral bodies and spinal canal height was recognized in the control group. However, no correlation between canal-body ratio with body height was seen in either group. A significant difference in canal-body ratio was seen between the control group and cervicl spondylotic myelopathy group (p<0.01).We consider that the canal-body ratio is an effective determination method for cervical canal stenosis.

Does the anteroposterior diameter of the bony spinal canal reflect its size? An anatomical study

Nine anatomical parameters that may have a relation to the spinal canal size were directly measured in each of 594 cervical and lumbar vertebrae from young adult cadaver skeletons. The anteroposterior diameter of the spinal canal was the only parameter which could be statistically correlated with its cross-sectional area (P less than 0.05), and hence justifies the accepted practice of its use as an indicator of bony spinal canal size.