Midsagittal Diameter Research Articles

Length of Lumbar Interbody Cage Using Radiological Measurements of Chinese Endplates and the Apophyseal Ring

To radiologically measure the parameters of endplates and the apophyseal ring and to suggest an applicable length for a lumbar interbody cage for Chinese patients. Twenty-four volunteers were enrolled to undergo lumbar computed tomography (CT). On the endplate plane, the diameters of the endplates (L1-S1) were measured along the axis of the cage with different lumbar interbody fusion procedures. Whereas the mid-oblique diameter (mid-OD) and maximum oblique diameter (max-OD) were defined as the minimal and maximal diameters of the endplates in transforaminal lumbar interbody fusion (TLIF), side-sagittal diameter (side-SD), mid-sagittal diameter (mid-SD), and transverse diameter (TD) represented the diameters of endplates in posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion (ALIF); and oblique lateral interbody fusion (OLIF)/extreme lateral interbody fusion (XLIF), /direct lateral interbody fusion (DLIF), respectively. R1-R10 were the widths of the apophyseal ring covered by diameters at both ends. We used the proposed formula to calculate the cage length: 1) minimal length of TLIF cage= mid-OD- ½ (R1+ R2), 2) maximal length of TLIF cage= max-OD- ½ (R3+ R4), 3) length of PLIF cage= side-SD- ½ (R5+ R6), 4) length of OLIF/XLIF/DLIF cage= TD- ½ (R7+ R8), and 5) length of ALIF cage= mid-SD- ½ (R9+ R10). The lengths of the TLIF cage were more than 30 mm for men and 26 mm for women in L1/2-L4/5, with a large range in L5-S1. For PLIF, the lengths were 28 to 30 mm for men and 24 to 26 mm for women in L1/2-L4/5, with 26 mm and 22 mm, respectively, in L5-S1. For the OLIF/XLIF/DLIF cage, the lengths were 38 mm in L1/2 and 41 to 43 mm in L2/3-L4/5 for men and 35 mm in L1/2-L2/3 and 38 mm in L3/4-L4/5 for women. The ALIF cage lengths were 27 mm in L1/2 and L5-S1 and 29 mm in L2/3-L4/5 for men and 23 mm in L1/2 and L5-S1 and 25 mm in L2/3-L4/5 for women. The choice of an appropriate length for a lumbar interbody cage should be based on the procedure and fusion level, which can match the endplates anatomically. The size of the lumbar interbody cage is affected by many factors, and a simple calculation may not be clinically relevant.

Torg’s ratio in normal adult nepalese population

Introduction: Acute cervical trauma occasionally leads to cervical canal stenosis in some individuals in spite of minor trauma. The spinal canal-to-vertebral body ratio (Torg-Pavlov ratio) has been proposed for assessing developmental spinal canal stenosis. It is not affected by magnification, and is measured on lateral plain films of cervical vertebrae. The result of this study may help in better understanding of the Torg’s ratio, which is more reliable than direct measuring of the mid-sagittal diameter of the cervical spinal canal in the diagnosis of cervical spinal stenosis or predicting the prognosis of cervical spinal cord injury. If Torg’s ratio is below normal there is risk of cervical cord injury whereas relatively safe in large Torg’s ratio. Torg’s ratio can be accessed even in rural areas where x-rays are easily available and more economical than MRI and CT scan. It can assess the risk of cord injury during sports and outdoor activities and help individuals’ choose safe carrier in sports or others activities.Methods: In order to ascertain the normal values of the Torg’s ratio in adults Nepalese, hundred sets of cervical vertebral columns of hundred adult Nepalese population of age group 20-40 years were examined. Consecutive patients presenting with history of neck pain with normal x-ray findings or history of trauma without cervical spine injury from Orthopaedic OPD (out patients department) and emergency department of Tribhuvan University Teaching Hospital, Maharajgunj, Kathmandu from March 2011 to August 2012 were included in the study.Results: There were 48 males and 52 females with age ranging from 20 yrs to 40 yrs with the mean of 30.34±5.36 years. The normal average canal/body ratio of the cervical spine is 0.99 +/- 0.09 in male and 1.01 +/- 0.07 in female. It was observed that the ratio of the antero-posterior diameters of cervical spinal canal and vertebral bodies showed sexual dimorphism.Conclusion: The Torg’s ratio is the same irrespective of gender and height. The result of this study will help in better understanding of the Torg’s ratio, which is more reliable than direct measuring of the mid-sagittal diameter of the cervical spinal canal in the diagnosis of cervical spinal stenosis or predicting the prognosis of cervical spinal cord injury.JSSN 2015; 18 (1), Page: 5-9

Defects of the vertebral end plate: implications for disc degeneration depend on size

Background ContextBony vertebral end plates must be porous to allow metabolite transport into the disc, and yet strong to resist high intradiscal pressure (IDP). End plate defects may therefore have nutritional and mechanical consequences for the disc, depending on their size and type. We hypothesize that broad, diffuse defects are more closely associated with disc decompression and degeneration than are focal Schmorl's node–type defects. PurposeThis study aimed to determine how the size and type of end plate defects are related to decompression and degeneration in the adjacent intervertebral disc. Study DesignMechanical, histologic, and micro-computed tomographic investigations were carried out in cadaver spines. MethodsThe study involved 40 motion segments (T8–T9 to L4–L5) dissected from 23 cadavers aged 48–98 years. Intradiscal stresses were measured, under 1 kN compression, by pulling a pressure transducer along the disc's midsagittal diameter. The resulting “stress profiles” revealed nucleus pressure (IDP) and maximum stresses in the anterior and posterior annulus. Micro-computed tomography was then used to examine all 40 discs, with 5 mm of adjacent bone on either side, so that end plate defects could be characterized at a resolution of 35 µm. Cross-sectional area (in the transverse plane), volume, location, and morphologic type were determined for all bony defects in the 80 end plates. Finally, discs from each motion segment (with hyaline cartilage and bone attached) were sectioned (undecalcified) at 7 µm for histology to allow degeneration to be assessed. ResultsSubstantial defects were identified in 24 of 40 specimens (35 of 80 end plates). Of these, 83% was centrally located, and 17% was laterally located. Defects occurred more frequently in male than female specimens (p=.043), and were more common in thoracic than lumbar end plates (p=.002), although lumbar defects were greater in volume (p=.05). Defect area and volume increased with decreasing IDP, with decreasing peak stress in the annulus, and with increasing tissue degeneration. Stepwise multiple regression showed that average defect area depended most strongly on IDP, whereas maximum defect area and volume depended most strongly on peak stress in the anterior annulus. Multiple end plate defects were associated with lower values of IDP and higher degeneration scores when compared with erosions and Schmorl's nodes. ConclusionsDisc degeneration has a stronger association with large or multiple end plate defects than with small or single defects (of any type). Large end plate defects probably allow greater volume changes within the disc, leading to greater nucleus decompression.

MRI Study on Spinal Canal Morphometry: An Indian Study.

A large proportion of adults suffer from neck pain at some points of their life and show altered ranges of spinal canal morphometry in various studies. The differences in values are also seen due to genetic, hormonal and other factors too. Torg's ratio is a widely accepted measurement to eliminate such discrepancies. The measurement of Space Available for Cord (SAC) is also gaining importance as spinal stenosis is a contributor to neck pain. (1) To examine the cervical spinal canal and spinal cord morphometric determinants in symptomatic sub-Himalayan North Bengal population and to compare the obtained data with other populations; (2) To determine whether Torg's ratio vary with gender or not; (3) To determine SAC values in symptomatic individuals. Magnetic Resonance Imaging (MRI) based on midsagittal diameter of vertebral body, spinal canal, spinal cord and its Torg's ratio and SAC value of the lower cervical spine (C3-C7) from 71 symptomatic adults were recorded at the Radiology Department of North Bengal Medical College and Hospital, Bengal, India. Individuals with any evidence of trauma, infection, neoplasia or any congenital anomalies related to spinal canal and below 18 years of age were excluded from the study. The average diameter for vertebral body was significantly larger in males. The average diameter for spinal canal, spinal cord and values of Torg's ratio and SAC has no significant gender difference. But the mean value of Torg's ratio is greater in females is due to smaller vertebral body size in females. It is interpreted from our study that sagittal spinal canal diameter, Torg's ratio and SAC value did not show any significant gender difference. But sagittal vertebral body's diameter showed sexual dimorphism which influenced the mean value of Torg's ratio.

EVALUATION OF THE DIAMETER OF THE LUMBAR VERTEBRAL CANAL USING COMPUTED TOMOGRAPHY IN MEXICAN POPULATION

ABSTRACT Objective: To conduct a descriptive study to find measures of central tendency in the vertebral bodies L3, L4, and L5 in the Mexican population. Methods: Fifty patients were considered, 33 male and 17 female, aged between 30 and 55 years. Measurements were performed at the levels L3, L4 and L5 taking the interpedicular distance (A), mid-sagittal diameter (B), anteroposterior distance (AP) and the depth of lateral recess (R) in axial 2-mm sections of CT scans (Somaton Emotion, SIEMENS, 2 sections) in a Mexican population with healthy vertebral bodies, with no history of lumbar pathology. Results: Overall, the measures obtained were mean interpedicular distance of 22.80 in L3, range of 16.34/28.72. In L4, mean of 23.83, range of 17.62/27.92. In L5, mean of 25.28, range of 21.88/31.29. Conclusions: This study managed to make a database that did not exist in Mexico, using measures of central tendency. Therefore, it opens the way for it to be possible, in future studies, to identify predictive factors or even developing implants.

A STUDY OF LUMBAR SPINAL CANAL BY MRI TO EVALUATE THE RISK OF SPINAL CANAL STENOSIS IN CLINICALLY SYMPTOMATIC PATIENTS

Background
 The study of lumbar spinal canal becomes important in persons with low backache and other related complaints particularly for the diagnosis of spinal canal stenosis.
 Objectives
 This study aims to measure the mid sagittal diameter of the lumbar spinal canal at the level of L3 and thus evaluating the risk of spinal canal stenosis.
 Methods
 The study was conducted on 106 kurdish patients complaining of lower backache using a 1.5 Tesla MRI scan in the imaging center of Sulaimani teaching hospital.
 Results
 The mean midsagittal diameter of bony spinal canal at the level of L3 was 12.32 ± 1.44 mm. About 52% of the patients had normal spinal canal diameter, while about 48% of the patients had a stenosed canal.
 Conclusion
 Midsagittal diameter of the spinal canal was smaller than what it was found in other populations and thus having a greater risk of spinal canal stenosis.

Porosity and Thickness of the Vertebral Endplate Depend on Local Mechanical Loading.

Mechanical and microcomputed tomography (micro-CT) study of cadaver spines. To compare porosity and thickness of vertebral endplates with (1) compressive stresses measured in adjacent intervertebral discs and (2) grade of disc degeneration. Endplate porosity is important for disc metabolite transport, and yet porosity increases with age and disc degeneration. We hypothesize that porosity is largely determined by mechanical loading from adjacent discs. Forty motion segments (T8-9 to L4-5) were dissected from 23 cadavers aged 48 to 98 years. Each was subjected to 1 kN compression during which time intradiscal stresses were measured by pulling a pressure transducer along the disc's midsagittal diameter. "Stress profiles" revealed the average pressure in the nucleus, and the maximum stress in the anterior and posterior annulus. Specimens were further dissected to obtain discs with endplates (and 5 mm of bone) on either side. Microcomputed tomography scans (resolution 35 μm) were analyzed to calculate thickness and porosity in the midsagittal regions of all 80 endplates. Average values for the anterior, central, and posterior regions of each endplate were obtained. Disc degeneration was assessed macroscopically and microscopically. Endplate porosity was inversely related to its thickness, being greatest in the central region opposite the nucleus, and least near the periphery. Superior endplates (relative to the disc) were 14% thicker (P < 0.001) and 4% less porous (P = 0.008) than inferior. In each of the 3 endplate regions (anterior, central, and posterior), porosity was inversely and significantly related to mechanical loading (pressure or maximum stress) in the adjacent disc region (P < 0.01 in all cases). Disc degeneration was best predicted by (reduced) nucleus pressure (R = 0.46, P < 0.001) and (reduced) maximum stress in the anterior annulus (R = 0.31, P < 0.001). Mechanical loading is a major determinant of endplate thickness and porosity. Disc degeneration is more closely related to reduced disc stresses than to endplate thickness or porosity. N/A.

Correlations between posterior longitudinal injury and parameters of vertebral body damage

BackgroundThe posterior longitudinal ligament (PLL) is an important structure of spinal stability. The loss of vertebral body height, local kyphosis (LK), and canal compromise may lead to spinal instability. This study determined the correlations between injury of the PLL and the loss of vertebrae height, kyphosis, and canal compromise. Materials and methodsA retrospective review of a thoracolumbar burst fracture database was conducted from January 2009 to December 2011. Patients were divided into an intact group and a disrupted group according to the status of the PLL. The loss of vertebral height, mid-sagittal canal diameter, and LK was measured. The anterior, middle, and posterior vertebral compression ratios (AVBCR, MVBCR, and PVBCR) and mid-sagittal diameter compression ratio (MSDCR) were calculated. ResultsForty-seven patients were included in the study, including 25 patients in the intact group and 22 patients in the disrupted group. There were significant differences in the AVBCR (t = −3.048, P = 0.004), MVBCR (t = −2.301, P = 0.048), PVBCR (t = −2.116, P = 0.040), and MSDCR (t = −4.095, P = 0.000) but no difference in the LK (t = 0.408, P = 0.686) between the two groups. There was a positive correlation between the injury of the PLL and the MSDCR (r = 0.428, P < 0.01), AVBCR (r = 0.372, P < 0.01), and PVBCR (r = 0.271, P < 0.05). There was no correlation between the injury of the PLL and the LK and MVBCR. ConclusionsThe MVBCR and LK are not predictive of a PLL injury. The MSDCR, AVBCR, and PVBCR were associated with a PLL injury.

Measurement and comparison of postoperative anterior cord space between C2-7 and C3-7 laminoplasty on MRI

To investigate the effect of C(2-7) laminoplasty on postoperative anterior cord space (ACS) compared with C(3-7) laminoplasty, and to provide evidence for reasonable enlargement of decompression range cephalad. Fifty-seven Patients underwent cervical laminoplasty from February 2008 to October 2011 were studied retrospectively, which were divided into two groups by decompression range: Group C(3-7) and Group C(2-7). The pre-and post operative JOA scores,VAS scores of neek and shoulder pain, and cervical alignment were compared in each group. The postoperative ACS at each level from C(2-3) to C(7)-T(1) measured on MRI were compared between the two groups. The postoperative JOA scores increased significantly in both groups. VAS scores and cervical alignment showed no significant difference. ACS at C(2-3) and C(3-4) was 6.13 mm (95%CI: 5.71-6.55) and 6.60 mm (95%CI: 6.10-7.11) respectively in Group C(3-7), which increased 2.5 mm and 2.1 mm respectively in Group C2-7 at the same segment, there was significant difference (P < 0.01). However, there was no significant difference of ACS at C(4-5) and any other caudal levels between the two groups. Compared with conventional C(3-7) laminoplasty, the extensive decompression cephalad to C(2) leads to larger ACS at C(2-3) and C(3-4). When the mid-sagittal diameter of anterior compression is more than 6.10 mm at C(3-4), C(3-7) laminoplasty may cause insufficient decompression, and enlargement of decompression range cephalad should be considered.

ISSLS Prize winner: Mechanical influences in progressive intervertebral disc degeneration.

Mechanical study on cadaver motion segments. To determine whether high gradients of compressive stress within the intervertebral disc are associated with progressive disc degeneration. Mechanical loading can initiate disc degeneration but may be unimportant in disease progression, because degenerative changes cause the disc to be increasingly "stress-shielded" by the neural arch. However, the most typical feature of advanced disc degeneration (delamination and collapse of the annulus) may not depend on absolute values of compressive stress but on gradients of compressive stress that act to shear annulus lamellae. A total of 191 motion segments (T7-T8 to L5-S1) were dissected from 42 cadavers aged 19 to 92 years. Each was subjected to approximately 1 kN compression, while intradiscal stresses were measured by pulling a pressure transducer along the disc's midsagittal diameter. "Stress gradients" in the annulus were quantified as the average rate of increase in compressive stress (MPa/mm) between the nucleus and the region of maximum stress in the anterior or posterior annulus. Measurements were repeated before and after creep loading and in simulated flexed and erect postures. Disc degeneration was assessed macroscopically on a scale of 1 to 4. As grade of disc degeneration increased from 2 to 4, nucleus pressure decreased by an average 68%, and maximum compressive stress in the annulus decreased by 48% to 64%, depending on location and posture. In contrast, stress gradients in the annulus increased by an average 75% in the anterior annulus (in flexed posture) and by 108% in the posterior annulus (in erect posture). Spearman rank correlation showed that these increases were statistically significant. Despite stress-shielding by the neural arch, gradients of compressive stress increase with increasing grade of disc degeneration. Stress gradients act to shear adjacent lamellae and can explain progressive annulus delamination and collapse. N/A.

Magnetic resonance imaging in the diagnosis of lumbar canal stenosis in Indian patients

Introduction: Magnetic resonance imaging (MRI) has become the choice of imaging modality for lumbar canal stenosis (LCS) due to limitations and radiation risks of computed tomography (CT) and spinal radiography. The radiological criteria for diagnosis of LCS are still ambiguous. Aim of this study is to find out the radiological dimensions on MRI of lumbar spinal canal in Indian patients and the critical dimensions at which the symptoms occur. Materials and Methods: A cross-sectional study was conducted in ESI Hospital, New Delhi from July 2011 to 2013. Two study groups were studied, the symptomatic LCS group, consisted of 30 individuals of either sex in age group of 45-65 years. The control group consisted of 30 asymptomatic age matched individuals. MRI scans were performed on 1.5 Tesla scanner. Dimensions of lumbar canal at all the levels (L1-L5) of lumbar vertebra of 60 patients were measured. Results: In our study, in symptomatic group, narrowest mid-sagittal diameter antero-posterior (mean 10.61) was at L5-S1 level. The interligamentous diameter (ILD) showed no significant difference between the two groups. Lateral recess depths showed a significant difference between the two groups at all levels except L1 on right side and L1 and L2 on left side. Critical canal dimension was found to be 11.13 mm. Conclusion: MRI can effectively evaluate the lumbar canal stenosis. The critical canal dimensions at which symptoms of stenosis appear were 11.13.

Normative MR Cervical Spinal Canal Dimensions

To provide normal values of the cervical spinal canal and spinal cord dimensions in several planes with respect to spinal level, age, sex, and body height. This study was approved by the institutional review board; all individuals provided signed informed consent. In a prospective multicenter study, two blinded raters independently examined cervical spine magnetic resonance (MR) images of 140 healthy volunteers who were white. The midsagittal diameters and areas of spinal canal and spinal cord, respectively, were measured at the midvertebral levels of C1, C3, and C6. A multivariate general linear model described the influence of sex, body height, age, and spinal level on the measured values. There were differences for sex, spinal level, interaction between sex and level, and body height, while age had significant yet limited influence. Normative ranges for the sagittal diameters and areas of spinal canal and spinal cord were defined at C1, C3, and C6 levels for men and women. In addition to a calculation of normative ranges for a specific sex, spinal level, age, and body height data, data for three different height subgroups at 45 years of age were extracted. These results show a range of the spinal canal dimensions at C1 (from 10.7 to 19.7 mm), C3 (from 9.4 to 17.2 mm), and C6 (from 9.2 to 16.8 mm) levels. The dimensions of the cervical spinal canal and cord in healthy individuals are associated with spinal level, sex, age, and height. Online supplemental material is available for this article.

Lumbar vertebral canal size in adults and children: Observations from a skeletal sample from London, England

The morphometry of the lumbar vertebral canal is of importance to clinical and bioarchaeological researchers, yet there are no growth standards for its diameters and there is a disagreement over the age at which its development is complete. Direct measurements of the midsagittal and interpedicular diameters of the lumbar vertebral canal (L1–L5) were taken from 65 children (3–17 years) and 120 adults (>17 years) from the East Smithfield Black Death cemetery, London (1348–1350 CE) to discover the age at which these diameters reached their final adult size in an historical population from later mediaeval London. Children were grouped into age categories: 3–5 years; 6–10 years; 11–14 years; 15–17 years, and the group means of each diameter were compared with the mean adult diameters using one-way ANOVAs. The child midsagittal diameters were not significantly different from adults in any age category, indicating that this diameter reached adult size by 3–5 years of age. However, interpedicular diameters increased with age until 15–17 years when they reached full adult size. Mean diameters and percentiles (10th and 90th) are provided for each age category.

Geometrical Dimensions and Morphological Study of the Lumbar Spinal Canal in the Normal Egyptian Population

Information regarding the precise dimensions of the lumbar vertebrae is essential for spinal surgery and instrumentation. When stenosis of the vertebral canal or the intervertebral foramen exists, the neural structures in them can be affected and cause symptoms such as low back or radicular pain. Accurate and comprehensive spinal canal measurements in the lumbar vertebrae are incomplete. The purpose of this study was to collect data on the dimensions of the lumbar spinal canal from computed tomography scans. Three hundred patients (162 men and 138 women) were studied. Computed tomography scans were obtained to determine the normal values of the midsagittal diameter, interpedicular distance, and lateral recess depth in the normal Egyptian population. The narrowest level was L3. The range of the midsagittal diameter was 11.07 to 26.07 mm at all levels. The range of the interpedicular distance was 17.00 to 43.41 mm at all levels. In all patients at all levels, mean lateral recess depth was 6.7 mm (range, 4-14 mm). The narrowest lateral recess depth was at L5. Few patients (3.3%) had a statistically stenotic midsagittal diameter measurement. The canal shape was not uniform along the 5 lumbar vertebrae; it ranged from being circular or rounded in the upper lumbar vertebrae to triangular in the midlumbar vertebrae to trefoil in the lower lumbar vertebrae, especially at L5. Trefoil canals existed mainly in the lower lumbar vertebrae at L5, followed by L4. Data from computed tomography scans combined with accurate measurements are the basis for anatomical studies, clinical research, and the development of implants suitable for a group of patients with measurements different from the population standard.

Radiological and Clinical Results of Laminectomy and Posterior Stabilization for Severe Thoracolumbar Burst Fracture : Surgical Technique for One-Stage Operation

This study aimed to show the possibility of neural canal enlargement and restoration of bony fragments through laminectomy and minimal facetectomy without pediculectomy or an anterior approach, and also to prove the adequacy of posterior stabilization of vertebral deformities after thoracolumbar bursting fracture. From January 2003 to June 2009, we experienced 45 patients with thoracolumbar burst fractures. All patients enrolled were presented with either a neural canal compromise of more than 40% with a Benzel-Larson Grade of VI, or more than 30% compromise with less than a Benzel-Larson Grade of V. Most important characteristic of our surgical procedure was repositioning retropulsed bone fragments using custom-designed instruments via laminectomy and minimal facetectomy without removing the fractured bone fragments. Beneath the dural sac, these custom-designed instruments could push the retropulsed bone fragments within the neural canal after the decompression and bone fragment repositioning. The mean kyphotic deformities measured preoperatively and at follow-up within 12 months were 17.7 degrees (±6.4 degrees) and 9.6 degrees (±5.2 degrees), respectively. The mean midsagittal diameter improved from 8.8 mm (±2.8 mm) before surgery to 14.2 mm (±1.6 mm) at follow-up. The mean traumatic vertebral body height before surgery was 41.3% (±12.6%). At follow-up assessment within 12 months, this score showed a statistically significant increase to 68.3% (±12.8%). Neurological improvement occurred in all patients. Though controversy exists in the treatment of severe thoracolumbar burst fracture, we achieved effective radiological and clinical results in the cases of burst fractures causing severe canal compromise and spinal deformity by using this novel custom-designed instruments, via posterior approach alone.

Predictors of outcome in acute traumatic central cord syndrome due to spinal stenosis

the objective of this study was to elucidate the relationship between admission demographic data, validated injury severity measures on imaging studies, and clinical indicators on the American Spinal Injury Association (ASIA) motor score, Functional Independence Measure (FIM), manual dexterity, and dysesthetic pain at least 12 months after surgery for acute traumatic central cord syndrome (ATCCS) due to spinal stenosis. over a 100-month period (January 2000 to April 2008), of 211 patients treated for ATCCS, 59 cases were due to spinal stenosis, and these patients underwent surgical decompression. Five of these patients died, 2 were lost to follow-up, 10 were not eligible for the study, and the remaining 42 were followed for at least 12 months. in the cohort of 42 patients, mean age was 58.3 years, 83% of the patients were men, and 52.4% of the accidents were due to falls. Mean admission ASIA motor score was 63.8 (upper extremities score, 25.8 and lower extremities score, 39.8), the spinal cord was most frequently compressed at skeletal segments C3-4 and C4-5 (71%), mean midsagittal diameter at the point of maximum compression was 5.6 mm, maximum canal compromise (MCC) was 50.5%, maximum spinal cord compression was 16.5%, and length of parenchymal damage on T2-weighted MR imaging was 29.4 mm. Time after injury until surgery was within 24 hours in 9 patients, 24-48 hours in 10 patients, and more than 48 hours in 23 patients. At the 1-year follow-up, the mean ASIA motor score was 94.1 (upper extremities score, 45.7 and lower extremities score, 47.6), FIM was 111.1, manual dexterity was 64.4% of baseline, and pain level was 3.5. Stepwise regression analysis of 10 independent variables indicated significant relationships between ASIA motor score at follow-up and admission ASIA motor score (p = 0.003), MCC (p = 0.02), and midsagittal diameter (p = 0.02); FIM and admission ASIA motor score (p = 0.03), MCC (p = 0.02), and age (p = 0.02); manual dexterity and admission ASIA motor score (p = 0.0002) and length of parenchymal damage on T2-weighted MR imaging (p = 0.002); and pain level and age (p = 0.02) and length of parenchymal lesion on T2-weighted MR imaging (p = 0.04). the main indicators of long-term ASIA motor score, FIM, manual dexterity, and dysesthetic pain were admission ASIA motor score, midsagittal diameter, MCC, length of parenchymal damage on T2-weighted MR imaging, and age, but different domains of outcome were determined by different predictors.

Is there a difference between narrowing of the spinal canal and neurological deficits comparing Denis and Magerl classifications?

Retrospective chart review. The objective of the current study was to evaluate the correlation between neurological deficits and the severity of narrowing of the spinal canal in patients with thoracic, thoracolumbar and lumbar burst-type fractures by comparing the classifications of Denis and Magerl. From 1989 to 2005, a total of 227 patients with burst fractures following Denis' criteria were studied. Tertiary teaching institution. Computed tomographic scans of the fractured spine were analyzed to assess the narrowing of the spinal canal. Following Magerl's criteria, patients were later subdivided into two groups according to the presence of associated ligament injuries, out of which 185 patients had no such injuries and the remaining 42 patients were classified as Megerl group B. Results were evaluated based on the initial neurological status of patients according to Frankel and based on the midsagittal diameter of the fractured vertebra. A significant correlation was found between the narrowing of the spinal canal and neurological deficits in both classifications, with no significant differences between either. The percentage of narrowing of the spinal canal proved to be a pre-disposing factor for the severity of the neurological status in thoracolumbar and lumbar burst-type fractures according to the classifications of Denis and Magerl. The greater the bone fragment in the spinal canal, the greater will be the probability of neurological deficits in both fracture classifications, equally.

Comparison of Radiography and Computed Tomography in Evaluating Posterior Indirect Reduction of Spinal Canal Bone Fragment

This article describes a retrospective study of patients who underwent posterior indirect reduction procedures for thoracolumbar burst fractures. The goal of this study was to explore a simple and effective method for evaluating the reduction of spinal canal fragments during posterior indirect reduction procedures.Sixty-four burst fractures with retropulsed bone fragments encroaching the spinal canal at the thoracolumbar junction were performed. C-arm fluoroscopy was used to evaluate the spinal canal fragments' reduction. A standard lateral view of the thoracolumbar spine was set up. When a continuous and smooth posterior vertebral body line of the injured vertebrae appeared, similar to below and above the vertebrae, the spinal canal bone fragment was considered to be satisfactorily reduced. The midsagittal diameter of the injured segment was measured on preoperative and postoperative computed tomography (CT) scans. Narrowing of the midsagittal diameter of the injured segment was improved from 41.4%+/-15.9% to 13.7%+/-9.7%. The correction value was 27.6%+/-15.6%. All pre- and postoperative outcome variables had statistical significance (P<.01). Forty-two patients experienced a restored posterior vertebral body line with a continuous and smooth vertical line, indicating that the fragment reduction was satisfactory. Post-operative CT showed that the spinal canal compromise was <10% (range, 0%-9.8%; mean, 6.1%+/-2.9%).Continuous and smooth posterior vertebral body line imaging is a simple and effective method to judge the reduction of a bone fragment retropulsed into the spinal canal. It can provide evidence as to whether a laminotomy and pushing the bone fragment are necessary during posterior surgery.

Lumbar Vertebral Canal Diameters in Adult Ugandan Skeletons

Background: Normal values of lumbar vertebral canal diameters are useful in facilitating diagnosis of lumbar vertebral canal stenosis. Various studies have established variation on values between different populations, gender, age, and ethnic groups. Objectives: To determine the lumbar vertebral canal diameters in adult skeletons according to gender, ethnicity, and vertebral levels at Galloway osteological collection of Makerere university. Methods: A descriptive cross-section study was carried out on 216 complete sets of male and female human lumbar vertebral bones. The midsagittal, transverse diameters of the lumbar vertebral canal and the anteroposterior diameter of the inferior vertebral notch were measured using an electronic digital caliper. Collected data was analyzed using SPSS 12.0 computer program. Results and discussion: In both sexes, the midsagittal diameter of the canal was wider at the cephalic than at the caudal end; reflecting the size of the contents at this level and also an adaptation to ensure protection of these contents during complex movements of this transition region . A steady widening of the transverse diameter of the canal from L1 to L5 was also observed in both genders. The anteroposterior diameter of inferior vertebral notch was subject to gender and ethnic variation. Conclusion: The narrowest midsagittal diameter is found at L3 in both genders, the widest transverse diameter on the other hand was at L5. Various diameters of the lumbar vertebral canal varied according to gender and ethnicity. Tanzania Medical Journal Vol. 23 (2) 2008: pp. 28-30

OC262: Quantification of the pelvic floor contraction using 3D/4D translabial ultrasound

Objectives: Magnetic resonance imaging (MRI) is the gold standard for the investigation of pelvic floor anatomy and function. The objective of this study was to compare biometric measures obtained by 3D ultrasound and MRI. Methods: In this prospective study, translabial 3D ultrasound and multiplanar MRI were used to assess pelvic floor anatomy in 27 nulliparous female volunteers. 3D ultrasound was performed using a GE Kretz Voluson 730/730 Expert system; MR images were obtained using a Siemens MAGNETOM Avanto 1.5-T scanner. All subjects were imaged supine and after voiding for both modalities. Data were acquired at rest, on pelvic floor muscle contraction and on maximal Valsalva. Results: All subjects were asymptomatic for pelvic floor dysfunction. Mean age was 29.3 (21–41) years, mean body mass index was 22.4 (18–29). Measures of hiatal diameters and areas obtained on MRI and 3D ultrasound were distributed normally. Sagittal hiatal diameters correlated at r = 0.533, P = 0.005 at rest, with ranges of 3.8–6.0 cm for MRI and 3.9–5.7 cm for ultrasound. On Valsalva, these figures were r = 0.658, P < 0.001, with ranges of 2.9–8.0 cm on MRI and 3.7–7.3 cm on ultrasound. On pelvic floor muscle contraction, the correlation was r = 0.503, P = 0.01 with ranges of 3.0–5.9 cm on MRI and 3.1–4.7 cm on ultrasound. As regards area measurements, correlations were r = 0.648 at rest and r = 0.542 on Valsalva (P < 0.01). Ranges were 9.1–18.1 on MRI vs. 9.2–17.8 on ultrasound at rest and 6.53–36.5 cm2 on MRI vs. 10.7–27.9 cm2 on ultrasound on Valsalva. There was a tendency for larger MRI measurements on Valsalva (P < 0.01 for area and midsagittal diameter). Repeatability measures were good to excellent for both methods. Conclusions: In this study of 3D ultrasound and MRI of the levator hiatus, correlations between methods were moderate but highly significant. MRI seemed to yield higher measurements on Valsalva, suggesting difficulties in identifying the plane of minimal dimensions during maneuvers that led to displacement of this plane.