The role of routine magnetic resonance imaging in the preoperative evaluation of adolescent idiopathic scoliosis

The routine use of magnetic resonance imaging (MRI) in adolescent idiopathic scoliosis remains controversial, and current indications for MRI in idiopathic scoliosis vary from study to study. The purpose of this study was to demonstrate the prevalence of neural axis malformations and the clinical relevance of routine MRI studies in the evaluation of patients with adolescent idiopathic scoliosis undergoing surgical intervention without any neurological findings. A total of 249 patients with a diagnosis of idiopathic scoliosis were treated surgically between the years 2002 and 2007. A routine whole spine MRI analysis was performed in all patients. On the preoperative clinical examination, all patients were neurologically intact. There were 20 (8%) patients (3 males and 17 females) who had neural axis abnormalities on MRI. Three of those 20 patients needed additional neurosurgical procedures before corrective surgery; the remaining underwent corrective spinal surgery without any neurosurgical operations. Magnetic resonance imaging may be beneficial for patients with presumed idiopathic scoliosis even in the absence of neurological findings and it is ideally performed from the level of the brainstem to the sacrum.     

Clinical value of routine preoperative magnetic resonance imaging in adolescent idiopathic scoliosis. A prospective study of three hundred and twenty-seven patients

BACKGROUND: The prevalence of intraspinal pathology associated with scoliosis has been reported to be as high as 26% in some series, and, on the basis of this finding, preoperative magnetic resonance imaging is used in the screening of patients with adolescent idiopathic scoliosis. However, this practice continues to be highly controversial. In order to better resolve this issue, we performed what we believe to be the largest prospective study to evaluate the need for preoperative magnetic resonance imaging in patients with adolescent idiopathic scoliosis requiring arthrodesis of the spine. METHODS: A total of 327 consecutive patients with adolescent idiopathic scoliosis were evaluated between December 1991 and March 1999. All patients in the study presented with an adolescent idiopathic scoliosis curve pattern and had a complete physical and neurologic examination. Magnetic resonance imaging of the brain and the spinal cord were performed as part of their preoperative work-up. RESULTS: Seven patients had an abnormality noted on magnetic resonance imaging. These abnormalities included a spinal cord syrinx in two patients (0.6%) and an Arnold-Chiari type-I malformation in four (1.2%). One patient had an abnormal fatty infiltration of the tenth thoracic vertebral body. No patient required neurosurgical intervention or additional work-up. All patients who underwent spinal arthrodesis with segmental instrumentation tolerated the surgery without any immediate or delayed neurologic sequelae. CONCLUSIONS: The fact that magnetic resonance imaging did not detect any important pathology in the large number of patients in this study strongly suggests that magnetic resonance imaging is not indicated prior to arthrodesis of the spine in patients with an adolescent idiopathic scoliosis curve pattern and a normal physical and neurologic examination.     

Evaluating congenital spine deformities for intraspinal anomalies with magnetic resonance imaging.

SUMMARY: The incidence of intraspinal abnormalities associated with congenital spinal anomalies as detected by magnetic resonance imaging (MRI) is becoming better defined. In this study, 41 nonrandomized children with congenital spinal deformities (excluding myelomeningocele) who underwent complete MR evaluation were reviewed. Of the 41 congenital spinal deformities, 37 demonstrated congenital scoliosis, with failure of formation in 19, failure of segmentation in 4, and mixed defects in 14. The remaining four deformities were cases of congenital kyphosis. Thirteen patients with congenital spine anomalies were noted to have intraspinal abnormalities identified by MRI: tethered cord in 12 patients, syringomyelia in 3 patients, and diastematomyelia in 5 patients. Of the 12 patients with tethered cord, 2 patients had neurologic deficits. Urorectal anomaly was one of the most common associated findings (15%). Considering an incidence of intraspinal anomalies of 31% and as clinical manifestations may not be initially detectable, MRI is recommended in patients with congenital spinal deformity as part of the initial evaluation even in the absence of clinical findings.     

Analysis of vertebral morphology in idiopathic scoliosis with use of magnetic resonance imaging and multiplanar reconstruction

BACKGROUND: Several studies have provided data on the vertebral morphology of normal spines, but there is a paucity of data on the vertebral morphology in patients with idiopathic scoliosis. METHODS: The morphology of the pedicles and bodies of 307 vertebrae as well as the distance between the pedicles and the dural sac (the epidural space) in twenty-six patients with right-sided thoracic idiopathic scoliosis were analyzed with use of magnetic resonance imaging and multiplanar reconstruction. RESULTS: A distinct vertebral asymmetry was found at the apical region of the thoracic curves, with significantly thinner pedicles on the concave side than on the convex side (p < 0.05). The degree of intravertebral deformity diminished farther away from the apex, with vertebral symmetry restored at the neutral level. In the thoracic spine, the transverse endosteal width of the apical pedicles measured between 2.3 mm and 3.2 mm on the concave side and between 3.9 mm and 4.4 mm on the convex side (p < 0.05). In the lumbar spine, the pedicle width measured between 4.6 mm at the cephalad part of the curve and 7.9 mm at the caudad part of the curve. The chord length and the pedicle length gradually increased from 34 mm and 18 mm, respectively, at the fourth thoracic vertebra to 51 mm and 25 mm, respectively, at the third lumbar vertebra. The transverse pedicle angle measured 15 in the cephalad aspect of the thoracic spine, decreased to 7 at the twelfth thoracic vertebra, and increased again to 16 at the fourth lumbar vertebra. The width of the epidural space was <1 mm at the thoracic apical vertebral levels and averaged 1 mm at the lumbar apical vertebral levels on the concave side, whereas it was between 3 mm and 5 mm on the convex side (p < 0.05). CONCLUSION: Idiopathic scoliosis is associated with distinctive intravertebral deformity, with smaller pedicles on the concave side and a shift of the dural sac toward the concavity.     

A new approach to corpus callosum anomalies in idiopathic scoliosis using diffusion tensor magnetic resonance imaging

Purpose

Idiopathic scoliosis (IS) is a frequent 3D structural deformity of the spine with a multi-factorial aetiology which remains largely unclear. In the last decade, human magnetic resonance imaging (MRI) morphometry studies (e.g. cortical thickness, 2D shape of the corpus callosum) have aimed to investigate the potential contribution of the central nervous system in the etiopathogenesis of IS. Recent developments in diffusion tensor imaging (DTI) allow us to extend the previous work to the study of white matter microstructure. Here, we hypothesized that part of the corpus callosum could show a difference in white matter microstructure in IS patients as compared to healthy controls.

Methods

We acquired DTI in 10 girls with IS and in 49 gender-matched controls to quantify the fractional anisotropy (FA) along the corpus callosum.

Results

Despite a very similar pattern of FA along the corpus callosum (maxima in the splenium and the genu and minimum in the isthmus), we found a significantly lower FA in the body in patients with IS as compared to control subjects. This region is known to connect the motor and premotor cortices of the two hemispheres.

Conclusion

This first diffusion magnetic resonance imaging brain study in IS patients, suggests that differences in white matter development, such as synchronization of axonal myelination and pruning could be involved in the etiopathogenesis of IS.     

Indications for magnetic resonance imaging in presumed adolescent idiopathic scoliosis

BACKGROUND: The use of magnetic resonance imaging has led to the diagnosis of abnormalities of the central nervous system associated with apparent idiopathic scoliosis. The indications for magnetic resonance imaging for presumed adolescent idiopathic scoliosis have not been established. METHODS: One thousand, two hundred and eighty children with presumed adolescent idiopathic scoliosis were evaluated over a ten-year period. Magnetic resonance imaging of the central nervous system (brainstem and spinal cord) was performed for specific patients, on the basis of the presence of selected indicators determined from the clinical history, physical examination, and plain radiographic examination of the spine. The medical records were reviewed to determine the specific indicators, the results of the imaging studies, and the subsequent treatment. RESULTS: Magnetic resonance imaging was ordered for 274 (21%) of the 1280 children who were evaluated. Abnormal findings were seen in twenty-seven (10%) of the 274 patients who underwent imaging, or 2% of the entire cohort. The most valuable single indicator of an abnormal finding on magnetic resonance imaging was absence of thoracic apical segment lordosis: eight of thirty-nine patients with that indicator had an abnormal finding on magnetic resonance imaging. The optimal diagnostic yield for a single category of indicators occurred when an atypical curve pattern was the only indicator: six of fifty-eight patients in whom this was the case had an abnormal finding on magnetic resonance imaging. None of the twenty children in whom pain was the only indicator category had an abnormal imaging study. The optimal diagnostic yield occurred when both an atypical curve pattern and neurological indicators were present: thirteen (25%) of fifty-three patients in whom this was the case had an abnormal finding on magnetic resonance imaging. Thirteen of the twenty-seven patients received surgical treatment for the abnormality of the central nervous system revealed by the imaging. CONCLUSIONS: The correct use of diagnostic tests is an important component of effective medical practice. An abnormality of the central nervous system is present in approximately 10% of patients with presumed adolescent idiopathic scoliosis in whom only subtle abnormalities are identified on the basis of the clinical history, physical examination, or radiographic examination. Knowledge of the diagnostic value of the specific clinical indicators, considered individually and in combination, can help the clinician to determine more effectively when advanced imaging of the central nervous system should be performed.     

Utility of preoperative functional magnetic resonance imaging for identifying language cortices in patients with vascular malformations

OBJECT: The goal of this study was to evaluate the utility of preoperative functional magnetic resonance (fMR) imaging in the prediction of whether a given cortical area would be deemed essential for language processing by electrocortical stimulation mapping (ESM). METHODS: The authors studied patients with vascular malformations, specifically arteriovenous malformations (AVMs) and cavernous angiomas, in whom blood-flow patterns are not normal and in whom a perfusion-dependent mapping signal may be questionable. Ten patients were studied (seven harboring AVMs and three with cavernous angiomas). The authors used a battery of linguistic tasks, including visual object naming, word generation, auditory responsive naming, visual responsive naming, and sentence comprehension, to identify brain regions that were consistently activated across expression and comprehension linguistic tasks. In a comparison of ESM and fMR imaging activations, the authors varied the matching criteria (overlapping activations, adjacent activations, and deep activations) and the radii of influence of ESM (2.5, 5, and 10 mm) to determine the effects of these factors on the sensitivity and specificity of fMR imaging. The sensitivity and specificity of fMR imaging were dependent on the task, lobe, and matching criterion. For the population studied, the sensitivity and specificity of fMR imaging activations during expressive linguistic tasks were found to be up to 100 and 66.7%, respectively, in the frontal lobe, and during comprehension linguistic tasks up to 96.2 and 69.8%, respectively, in the temporal and parietal lobes. The sensitivity and specificity of each disease population (patients with AVMs and those with cavernous angiomas) and of individuals were consistent with those values reported for the entire population studied. CONCLUSIONS: The authors conclude that preoperative fMR imaging is a highly sensitive preoperative planning tool for the identification of which cortical areas are essential for language and that this imaging modality may play a future role in presurgical planning for patients with vascular malformations.     

Dural ectasia in adolescent idiopathic scoliosis: quantitative assessment on magnetic resonance imaging

To our knowledge, the assessment of dural sac diameters in patients with adolescent idiopathic scoliosis (AIS) is not reported in the literature. The aim of this study was to find out if, dural ectasia occurs more frequently among patients with AIS, to define cut-off values for dural sac ratio and test the validity of such values. A total of 126 spine MRIs (79 patients with AIS and 47 control subjects) were included in this retrospective analysis (age range 7–25 years, 62% were females). Dural sac diameter (DSD) and vertebral body diameter (VBD) were estimated and dural sac ratio (DSR = DSD/VBD) was calculated at T5 and L3. DSR at T5 and L3 were 0.69 ± 0.12, and 0.52 ± 0.10, respectively, in patients with AIS compared with 0.62 ± 0.11, and 0.44 ± 0.07, respectively, in controls (P = 0.001 at T5 and <0.001 at L3). Our estimated cut-off values for DSR were 0.84 and 0.58 at T5 and L3, respectively. This resulted in 100% sensitivity compared with 74% when using the cut-off values proposed by Oosterhof et al. No statistically significant association was found between the occurrence of dural sac enlargement in patients with AIS and the severity of scoliotic deformity, the apical vertebral rotation, epidural fat thickness, occurrence of pain, neurological deficit, atypical scoliosis or rapid curve progression. Females were affected more frequently than males. As dural sac enlargement means thinning of the pedicles, we believe that the findings of this study have important clinical implications on the preoperative workup of AIS.     

Intraspinal anomalies associated with isolated congenital hemivertebra: the role of routine magnetic resonance imaging

BACKGROUND: Previous studies have demonstrated high rates of intraspinal anomalies in patients with congenital scoliosis; however, various authors have not considered the presence of an isolated hemivertebra to be sufficient reason for further evaluation with magnetic resonance imaging. Consequently, the rate of magnetic resonance imaging-detected intraspinal anomalies and subsequent neurosurgical intervention in patients with a single hemivertebra is unknown. Therefore, we studied all patients with a hemivertebra, after eliminating patients with a myelomeningocele, to compare those who had a single hemivertebra with those who had a complex hemivertebral pattern. METHODS: A retrospective review of the history, physical examination findings, and magnetic resonance imaging findings for patients who had presented with at least one hemivertebra, excluding those who had a myelomeningocele, was conducted to identify the prevalence of intraspinal anomalies as seen on magnetic resonance imaging and the rate of subsequent neurosurgical intervention. Additionally, the diagnostic value of the history and the physical examination in predicting the presence of intraspinal anomalies was determined. RESULTS: One hundred and sixteen patients with congenital scoliosis and a curve that included at least one hemivertebra were identified. Seventy-six of these patients had had magnetic resonance imaging and were included in the present study. The mean age of these patients at the time of presentation was 4.9 years, and the mean duration of follow-up was 7.7 years. Twenty-nine patients had an isolated hemivertebra, and forty-seven patients had a complex hemivertebral pattern. Eight (28%) of the twenty-nine patients with an isolated hemivertebra and ten (21%) of the forty-seven patients with a complex hemivertebral pattern had an intraspinal anomaly that was detected with magnetic resonance imaging. Overall, an abnormal finding on the history or physical examination demonstrated an accuracy of 71%, a sensitivity of 56%, a specificity of 76%, a positive predictive value of 42%, and a negative predictive value of 85% for the diagnosis of an intraspinal anomaly. Three patients with an isolated hemivertebra and five patients with a complex hemivertebral pattern underwent neurosurgical intervention. All eight patients who underwent neurosurgical intervention had had detection of an intraspinal anomaly with magnetic resonance imaging, whereas only four of these patients (two of whom had an isolated hemivertebra and two of whom had a complex hemivertebral pattern) had had an abnormal finding on either the history or the physical examination. CONCLUSIONS: Patients who have an isolated hemivertebra and those who have a complex hemivertebral pattern have similar rates of intraspinal anomalies that are detected with magnetic resonance imaging and similar rates of subsequent neurosurgical intervention. The history and physical examination findings are not predictive of intraspinal anomalies. Therefore, a magnetic resonance imaging evaluation of the entire spine should be considered for all patients with congenital scoliosis, including those with an isolated hemivertebra.     

The Dwyer procedure in the treatment of idiopathic scoliosis. A 10-year follow-up review of 21 patients

Despite the well-known Dwyer procedure, developed in 1969, comprehensive reports on its use, with long-term follow-up, are relatively scarce. The purposes of this study were to detect eventual late complications and to compare late results with postoperative angular curve correction. This article reports on 21 children operated on between October 1972 and October 1975 and reviewed with a minimum follow-up of 10 years (10 other patients were lost to follow-up after 5 years). Patients had idiopathic lumbar or thoracolumbar curves (average curve, 56 degrees). Results are discussed with a special reference to longitudinal observation. There is a great correction of the instrumented curve (postoperative, 5 degrees), but a loss of correction of 10 degrees is generally observed, prevented by a complete immediate correction or even hypercorrection. The upper curve, noninstrumented, also shows improvement (mean preoperative, 38 degrees; postoperative, 22 degrees; 10 years, 22 degrees) but re-equilibration cannot be predicted. Pseudarthrosis of one intervertebral space occurs frequently, and may cause failure of the cable with a loss of correction of 10-20 degrees. Kyphosis (or simple loss of lumbar lordosis) is commonly observed but should be balanced with correction of rotation. The following conclusions were made: morbidity is not severe, despite the advanced surgical technique. The technique is difficult and has a direct consequence on the quality of results; pseudarthrosis is a frequent complication, followed by important loss of correction; indications should be discussed carefully in idiopathic lumbar and thoracolumbar curves. It is still too early to advocate either anterior instrumentation of Zielke (VDS) or segmental posterior instrumentation (C. D. Luque) because of short-term follow-up.     

Juvenile and adolescent idiopathic scoliosis: magnetic resonance imaging evaluation and clinical indications

The aims of this study were (1) to determine the rate of 'idiopathic' scoliosis associated with neuroanatomical abnormalities of the posterior cerebral fossa (PCF), spinal canal (SC) or central nervous system (CNS), and (2) to identify any clinical, neuro-orthopedic criteria, radiological curve pattern or other variable which could justify magnetic resonance imaging (MRI) as complementary study. Fifty-six patients with juvenile and adolescent scoliosis, were prospectively evaluated with MRI of the PCF and SC. All the patients were categorized into four different groups according to neuro-anatomical abnormalities on MRI (groups A, B, C and D). Eleven patients (19.6%) presented neuroanatomical abnormalities of the PCF and SC (group A), four patients (7.1%) presented pathological conditions of the CNS (group B) and three patients (5.4%) presented anomalies at the osseous spine and abdomen (group C). The remaining 38 patients (67.9%) presented with normal MRI results (group D). Of the patients in group A, 81.8% were neurologically normal. In this group, the right and left thoracic curve patterns were seen in the same number of patients (four of 11 each). Early diagnosis of neuroanatomical abnormalities of the PCF, SC and CNS could be achieved in 26.7% of cases (groups A and B). The most significant finding was the chronological age: 36.4% of patients in group A were under the age of 11 years. In addition, it would be recommended that in patients with scoliosis and a surgical indication, MRI results should be to take into consideration as a complementary preoperative evaluation because four of 15 patients (26.7%) with an indication for spinal fusion and who were neurologically normal, sustained some of the conditions included in groups A and B.     

Longitudinal magnetic resonance imaging study on whiplash injury patients: minimum 10-year follow-up

Background

We conducted a prospective long-term follow-up study to assess associations between magnetic resonance imaging (MRI) findings and changes in clinical symptoms, as well as factors relating to the prognosis of symptoms.

Methods

A total of 133 patients with acute whiplash injury between 1993 and 1996 participated in this follow-up study. They underwent neurological examinations by spine surgeons and second MRI scans of the cervical spine were obtained. They also filled out a questionnaire regarding cervical symptoms and the accident details. The items evaluated by MRI were (1) a decrease in the signal intensity of the intervertebral disc; (2) anterior compression of the dura and the spinal cord; (3) posterior disc protrusion; (4) disc space narrowing; and (5) foraminal stenosis. Relations between the presence/absence of degenerative changes on MRI, accident details, and patients’ symptoms were assessed by calculating the adjusted odds ratio (OR).

Results

Progression of some degenerative changes was recognized on MRI in 98.5% of the 133 whiplash injury patients, and clinical symptoms diminished in more than a half of the 133 patients. There were no statistically significant associations between MRI findings and changes in clinical symptoms. The prognosis for neck pain tended to be poor after accidents with double collisions (rear-end collision followed by frontend collision) [adjusted OR 5.83, 95% confidence interval (CI) 1.15-29.71] and accidents with serious car damage (2.87, 1.03–7.99). The prognosis for stiff shoulders tended to be poor in women (2.83, 1.23–6.51); and the prognosis for numbness in the upper extremities tended to be poor after accidents with serious car damage (3.39, 1.14–10.06).

Conclusions

This study demonstrated that progression of degenerative changes of the cervical spine on MRI was not associated with clinical symptoms during the 10-year period after whiplash injury.     

脊柱侧凸合并脊髓病变的手术治疗进展

<正>随着磁共振成像(magnetic resonance imaging,MRI)技术在脊柱外科中的广泛应用,包括拟诊为特发性脊柱侧凸(idiopathic scoliosis,IS)在内的许多脊柱侧凸畸形被发现合并有脊髓病变~([1、2])。目前,关于脊髓病变与脊柱侧凸之间的伴发关系仍不清楚。此外,对于此类合并脊髓病变的脊柱侧凸,在进行脊柱畸形矫正时是否需要处理伴发的脊髓病变、如何处理及何时处理等尚未达成共识。笔者就此     

特发性脊柱侧凸脊髓异常的MRI评价

脊柱侧凸是一种常见的脊柱畸形,其中特发性脊柱侧凸约占70%,其在儿童青少年中的发病率约为1%～3%.随着影像学检查的深入,尤其是MRI在特发性脊柱侧凸中的应用,越来越多的脊髓异常被发现,其意义尚待进一步探讨.     

The importance of sagittal alignment in patients with adolescent idiopathic scoliosis and early onset scoliosis: A review on preoperative versus postoperative changes

Scoliosis is a three-dimensional spine deformity that in pediatric patients can progressively worsen to cause esthetic issues in adolescent idiopathic scoliosis (AIS) and lung complications in early-onset scoliosis (EOS). Previous emphasis was placed on only correcting coronal plane deformity, but recent research has demonstrated the importance of correcting sagittal plane alignment as well. Failure to do so can lead to adjacent segment disease or abnormal global sagittal balance which negatively affects quality of life. This review article summarizes current concepts of sagittal spine alignment in terms of radiographic parameters, outcomes, and complications when surgically treating patients with AIS and EOS.     

青少年特发性脊柱侧凸胸椎形态学的MRI测量及临床意义

目的 通过磁共振成像(MRI)观察青少年特发性脊柱侧凸(AIS)和正常同年龄组青少年胸椎的形态学差异,探讨其临床意义.方法 胸椎轻度侧凸(MS)组患者10例(Cobb角15°～39°),胸椎中度侧凸(SS)组患者10例(Cobb角40°～75°).另选健康青少年10名作为对照(非侧凸组).所有研究对象均为女性,年龄13～14岁.用1.5 T磁共振扫描仪(Sonata,Siemens,Erlanger,德国)对所有研究对象进行全脊柱矢状面扫描,在图像工作站(Easy Vision,Philips Medical Systems,Best,荷兰)上重建脊柱矢状面图像,测量每个胸椎椎体前壁高度,后壁高度,棘突间高度,在横截面测量椎体横径长度,并进行对比分析.结果 椎体前后高度、宽度从T1到T12逐渐增加,并呈线性分布,脊柱侧凸组椎体高度普遍>正常同年龄非侧凸组患者.脊柱侧凸组患者椎体高度横径比值以及脊椎前后高度比值均>无侧凸组.胸椎侧凸顶椎区T6～T9椎体前方高度、椎体高度横径比值以及脊椎前后高度比值,脊柱侧凸组明显>非侧凸组,差异均有统计学意义(P<0.05).结论 AIS胸椎侧凸女性患者胸椎顶椎区存在显著的脊柱生长模式异常,与正常胸椎相比AIS的胸椎更高、并显得更为瘦长.     

Improving the safety of laparoscopic cholecystectomy: the routine use of preoperative magnetic resonance cholangiography

Background The aim of this study was to determine the value of routinely performed preoperative magnetic resonance cholangiography (MRC) in detecting common bile duct (CBD) stones in patients stated to undergo elective laparoscopic cholecystectomy. In addition, we used MRC to investigate possible variants of the cystic duct.Methods Magnetic resonance cholangiography was performed preoperatively in 773 patients (311 male and 462 female; median age 55 years, range 16–91) who had no clinical signs of cholestasis prior to undergoing elective laparoscopic cholecystectomy. In cases where the MRC was positive for CBD stones, endoscopic retrograde cholangiopancreatiography (ERCP) was then performed. A total of 532 patients were available for continuous postoperatively follow-up (median 54 months, range 36–85). In 462 patients (247 female, and 215 male), MR images were also reviewed for variants of the cystic duct.Results In 705 patients (91%), MRC was negative for CBD stones. In 64 patients (9%) MRC was positive. Of these patients, 47 (6%) had CBD stones on ERCP. In 12 patients (2%), MRC was false positive. In five cases (0.6%), ERCP had an inconclusive result postoperative follow-up (532 patients, or 69%) revealed evidence of CBD stones in three patients (10.4%) despite a preoperative negative MRC result. Anatomical variants in the course of the cystic duct and its confluence with the common bile duct were found in 27 of 462 patients (6%).Conclusions Magnetic resonance cholangiography proved to be a reliable screening technique in the preoperative evaluation of patients with silent CBD stones. Imaging of the course of the cystic duct is possible in a high percentage of cases. Therefore, MRC can be recommended as a screening technique before laparoscopic cholecystectomy.