Morphometric analysis of neurocentral synchondrosis using magnetic resonance imaging in the normal skeletally immature spine

Digital anatomical features of morphological development in C2-C7 neurocentral synchondrosis in children aged 1-6 years: a retrospective study of CT images

BACKGROUND

With the continuous improvement of diagnosis and treatment technology for cervical spine-related diseases in children at home and abroad, the demand for exploring the developmental anatomy and function of children's cervical spine of different ages is increasing. So the aim of this study was to investigate the changes of anatomical indicators in neurocentral synchondrosis (NCS) of C2-C7 with age and the developmental characteristics of different vertebrae in children aged 1-6 years old.

METHOD

A retrospective collection of 160 cases of normal cervical spine CT images of children aged 1-6 years old in provincial tertiary hospitals, according to the age group of 1-year-old into 6 groups. The original data of continuously scanned cervical spine tomography images were imported into Mimics16.0 software, under the two-dimensional image window, selected the measurement tool under the Measurements toolbar to measure and statistically analyzed the anatomical indicators such as cross diameter, sagittal diameter, height, perimeter and area of NCS in the C2-C7 segment of the cervical spine on the coronal plane and cross-section.

RESULTS

There was no significant difference in the anatomical indexes of cervical spine NCS in children compared with the left and right sides of the same vertebrae (P > 0.05). The same cervical spine generally had differences between the age groups of 1-4 years old and 5-6 years old (P < 0.05).The transverse diameter and circumference gradually decreased with age; the sagittal diameter and height showed a slight increase trend; there was a maximum area at 2 years of age. In different cervical vertebrae of the same age group, the NCS values of C3, C4, and C5 varied greatly, which showed that the ossification process of cervical cartilage was faster than that at the upper and lower ends. There were obvious differences between C2 and the rest of the cervical vertebral segments' NCS ossification process. C7 was also very different from the rest of the cervical vertebrae segments, presumably more similar to the thoracic spine.

CONCLUSIONS

The anatomical indexes of C2-C7 NCS in children have obvious developmental regularities at different ages, and there are also regularities between cervical segments.

Meeting Report from 2nd ICCBH-ERN BOND Spinal Complications in Children and Adults with Achondroplasia Workshop, Dublin, Ireland, 2nd July 2022

A pre-meeting workshop on spinal complications in children and adults with achondroplasia was held in Dublin, Ireland at the 10th International Conference on Children's Bone Health (ICCBH) 2-5 July 2022. The pathophysiology, natural history and medical/surgical management of thoraco-lumbar kyphosis and spinal stenosis remains poorly described in the literature. The structure of the workshop consisted of lectures, a debate and an interactive round table discussion. In total over 100 delegates affiliated to over 70 institutions from 20 countries were in attendance.

The earliest Pleistocene record of a large-bodied hominin from the Levant supports two out-of-Africa dispersal events

The paucity of early Pleistocene hominin fossils in Eurasia hinders an in-depth discussion on their paleobiology and paleoecology. Here we report on the earliest large-bodied hominin remains from the Levantine corridor: a juvenile vertebra (UB 10749) from the early Pleistocene site of 'Ubeidiya, Israel, discovered during a reanalysis of the faunal remains. UB 10749 is a complete lower lumbar vertebral body, with morphological characteristics consistent with Homo sp. Our analysis indicates that UB-10749 was a 6- to 12-year-old child at death, displaying delayed ossification pattern compared with modern humans. Its predicted adult size is comparable to other early Pleistocene large-bodied hominins from Africa. Paleobiological differences between UB 10749 and other early Eurasian hominins supports at least two distinct out-of-Africa dispersal events. This observation corresponds with variants of lithic traditions (Oldowan; Acheulian) as well as various ecological niches across early Pleistocene sites in Eurasia.

Older fusion-surgery age in congenital scoliosis patients is a risk factor for extended length of stay, more estimated blood loss, longer fused segments and higher medical costs: a retrospective study

Background

Contradictory opinions about whether early correction and fusion surgeries should be performed for congenital scoliosis (CS) patients at a young age exist. The objectives of this study were to analyze the association between patient characteristics and fusion-surgery outcomes in CS patients treated with spinal correction and fusion surgeries and to report risk factors for extended length of stay (LOS), more estimated blood loss (EBL), longer fused segments and higher medical costs.

Methods

We analyzed data of 1,207 CS inpatients treated with fusion surgeries in our institute from January 2010 - December 2019. All patients underwent spinal X-ray, CT, MRI, echocardiogram and urogenital ultrasound. We analyzed demographic and clinical information and outcome measures, including LOS, EBL, fused segments and medical costs.

Results

Age at fusion (OR = 1.053; p < 0.001), musculoskeletal defects (OR = 1.670; p = 0.004) and thoracic deformity (OR = 1.519; p = 0.03) were risk factors for extended LOS. Age at fusion (OR = 1.117; p < 0.001), male sex (OR = 1.813; p < 0.001), mixed defects (OR = 1.662; p = 0.027) and failure of formation (OR = 1.718; p = 0.021) were risk factors for more EBL. Age at fusion (OR = 1.213; p < 0.001) was a risk factor for longer fused segments. Age at fusion (OR = 1.091; p < 0.001) and thoracic deformity (OR = 1.853; p = 0.004) were risk factors for higher medical costs.

Conclusions

We found that older age at fusion in CS patients is a risk factor for extended LOS, more EBL, longer fused segments and higher medical costs with the risk increasing by 5–21 % for each year of age. Other identified risk factors include thoracic deformity for extended LOS; longer fused segments, higher medical costs, and musculoskeletal defects for extended LOS; and CS type (FF and MD) and sex (male) for more EBL.

Structural spinal abnormalities on MRI and associations with weight status in a general pediatric population

BACKGROUND CONTEXT

Several spinal abnormalities have been studied using magnetic resonance imaging (MRI). However, in children these studies were sparsely performed in general populations. Examining young children's spines is important since the shape of the bone is largely determined during the growth spurt. Furthermore, it is so far unknown if associations between weight status and spinal abnormalities, which are known for adolescents and adults, are already present in young children.

PURPOSE

We aimed to present the prevalence of structural abnormalities in the prepubertal pediatric spine on MRI and their association with measures of the children's body weight and body composition.

STUDY DESIGN

Cross-sectional study embedded in a prospective population-based birth cohort study.

PATIENT SAMPLE

For this study, participants from the Generation R Study were selected based on the availability of MRI data of the lumbar spine and accelerometry data at the age of 9 years.

OUTCOME MEASURES

The presence of structural abnormalities of intervertebral discs and vertebrae was scored on MRI. The body mass index-standard deviation [BMI-SD] score was calculated from objectively measured weight and height, and body composition measurements were obtained by a dual-energy X-ray absorptiometry scan.

METHODS

A semiquantitative scoring tool to assess the intervertebral discs and vertebrae of the lumbar spine on conventional MRI was designed for this purpose. Proportions of children with spinal abnormalities on at least one lumbar vertebral level were presented. Logistic regression was used to analyze associations between abnormalities and weight and body composition. We declare not to have any financial conflicts of interests.

RESULTS

We included 559 children (median age of 9.88 years (interquartile range 6.74-10.02), 48.5% boys). Most frequently observed abnormalities of the intervertebral discs were abnormal signal intensity (24.9%), decreased or collapsed disc height (37.6%), disc bulging (73.3%), and abnormal nuclear shape (29.1%). Vertebral endplate irregularities and lumbosacral transitional vertebrae were seen in respectively 40% and 9.3% of the participants. Except for disc bulging, all abnormalities were predominantly present at the L5 level. Only the presence of endplate irregularities was associated with a higher body weight (BMI SD score (odds ratio [OR] 1.50 [95% confidence interval [CI] 1.21-1.86]) and BMI SD change (OR 1.48 [95% CI 1.07-2.03])) and increased body mass values in body composition measurements (% body fat (OR 1.05 [95% CI 1.02-1.09), fat mass index (OR 1.23 [95% CI 1.09-1.39]), and fat-free mass index (OR 1.30 [95% CI 1.06-1.59])) in adjusted analyses.

CONCLUSIONS

Structural spinal abnormalities, especially disc bulging, endplate irregularities, and an abnormal disc height, are already present in children aged 9 years from a Dutch population-based cohort. Of those abnormalities, endplate irregularities are associated with various weight and body composition measurements.

A pilot study of influence of pedicle screw instrumentation on immature vertebra: a minimal 5-year follow-up in children younger than 5 years

OBJECTIVE

Concerns remain over the influence of pedicle screw instrumentation on the growth potential of an immature spine. Previous studies have reported discrepancies between animal experiments and clinical studies. The authors' objective was to explore the influence of pedicle screw instrumentation on the growth of an immature spine at a very young age.

METHODS

Individuals who met the authors' criteria were included. Anteroposterior diameter of the vertebral body; pedicle length on both sides; and anteroposterior diameter, transverse diameter, and area of the spinal canal were measured on CT images before surgery and at the final follow-up. Parameters of instrumented vertebrae and adjacent noninstrumented vertebrae were compared. The growth value and growth percentage of each parameter were calculated. Subgroup comparisons were made in thoracic vertebrae and lumbar vertebrae. Statistical analyses were performed.

RESULTS

Thirteen patients with a congenital spinal deformity were included in the study. The average age at surgery was 3.4 (range 2-5) years, and the average follow-up was 7.2 (range 5-11) years. Osteotomy and short instrumentation with pedicle screws were performed in each case. A total of 69 segments were measured, including 43 instrumented vertebrae and 26 immediately adjacent noninstrumented vertebrae. Significant increases in all parameters were noted at the final follow-up. In instrumented vertebrae, growth of the pedicle length and the anteroposterior diameter and area of the spinal canal increased significantly, while growth of the anteroposterior diameter of the vertebral body decreased significantly compared with noninstrumented vertebrae. Similar results were noted in the lumbar region. The shape-change phenomenon was found in noninstrumented vertebrae but was not apparent in instrumented vertebrae.

CONCLUSIONS

Pedicle screw instrumentation may slow down growth of the vertebral body, indirectly speed up growth of the spinal canal, and hinder the shape-change phenomenon of the lumbar spinal canal. However, the influences were quite slight, and significant development did occur in instrumented vertebrae. Therefore, pedicle screw instrumentation may not have much effect on the growth of immature vertebrae in children younger than 5 years.

Maternal Diets Deficient in Vitamin D Increase the Risk of Kyphosis in Offspring: A Novel Kyphotic Porcine Model

BACKGROUND

The purpose of this study was to explore the role of perinatal vitamin-D intake on the development and characterization of hyperkyphosis in a porcine model.

METHODS

The spines of 16 pigs were assessed at 9, 13, and 17 weeks of age with radiography and at 17 weeks with computed tomography (CT), magnetic resonance imaging (MRI), histology, and bone-density testing. An additional 169 pigs exposed to 1 of 3 maternal dietary vitamin-D levels from conception through the entire lactation period were fed 1 of 4 nursery diets supplying different levels of vitamin D, calcium, and phosphorus. When the animals were 13 weeks of age, upright lateral spinal radiography was performed with use of a custom porcine lift and sagittal Cobb angles were measured in triplicate to determine the degree of kyphosis in each pig.

RESULTS

The experimental animals had significantly greater kyphotic sagittal Cobb angles at all time points when compared with the control animals. These hyperkyphotic deformities demonstrated no significant differences in Hounsfield units, contained a slightly lower ash content (46.7% ± 1.1% compared with 50.9% ± 1.6%; p < 0.001), and demonstrated more physeal irregularities. Linear mixed model analysis of the measured kyphosis demonstrated that maternal diet had a greater effect on sagittal Cobb angle than did nursery diet and that postnatal supplementation did not completely eliminate the risk of hyperkyphosis.

CONCLUSIONS

Maternal diets deficient in vitamin D increased the development of hyperkyphosis in offspring in this model.

CLINICAL RELEVANCE

This study demonstrates that decreased maternal dietary vitamin-D intake during pregnancy increases the risk of spinal deformity in offspring. In addition, these data show the feasibility of generating a large-animal spinal-deformity model through dietary manipulation alone.

The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)

Ontogenetic studies help us understand the processes of evolutionary change. Previous studies on Neandertals have focused mainly on dental development and inferred an accelerated pace of general growth. We report on a juvenile partial skeleton (El Sidrón J1) preserving cranio-dental and postcranial remains. We used dental histology to estimate the age at death to be 7.7 years. Maturation of most elements fell within the expected range of modern humans at this age. The exceptions were the atlas and mid-thoracic vertebrae, which remained at the 5- to 6-year stage of development. Furthermore, endocranial features suggest that brain growth was not yet completed. The vertebral maturation pattern and extended brain growth most likely reflect Neandertal physiology and ontogenetic energy constraints rather than any fundamental difference in the overall pace of growth in this extinct human.

Growth Patterns of the Neurocentral Synchondrosis (NCS) in Immature Cadaveric Vertebra

STUDY DESIGN

Gross anatomic study of osteological specimens.

OBJECTIVES

To evaluate the age of closure for the neurocentral synchondrosis (NCS) in all 3 regions of the spine in children aged 1 to 18 years old.

SUMMARY OF BACKGROUND DATA

The ossification of the human vertebra begins from a vertebral body ossification center and a pair of neural ossification centers located within the centrum called the NCS. These bipolar cartilaginous centers of growth contribute to the growth of the vertebral body, spinal canal, and posterior elements of the spine. The closure of the synchondroses is dependent upon location of the vertebra and previous studies range from 2 to 16 years of age. Although animal and cadaveric studies have been performed regarding NCS growth and early instrumentation's effect on its development, the effects of NCS growth disturbances are still not completely understood.

METHODS

The vertebrae of 32 children (1 to 18 y old) from the Hamann-Todd Osteological collection were analyzed (no 2 or 9 y old specimens available). Vertebrae studied ranged from C1 to L5. A total of 768 vertebral specimens were photographed on a background grid to allow for measurement calibration. Measurements of the right and left NCS, pedicle width at the NCS, and spinal canal area were taken using Scandium image-analysis software (Olympus Soft Imaging Solutions, Germany). The percentage of the growth plate still open was found by dividing the NCS by the pedicle width and multiplying by 100. Data were analyzed with JMP 11 software (SAS Institute Inc., Cary, NC).

RESULTS

The NCS was 100% open in all 3 regions of the spine in the 1- to 3-year age group. The cervical NCS closed first with completion around 5 years of age. The lumbar NCS was nearly fully closed by age 11. Only the thoracic region remained open through age 17 years. The left and right NCS closed simultaneously as there was no statistical difference between them. In all regions of the spine, the NCS appeared to close sooner in males than in females. Spinal canal area increased with age up to 12 years old in the cervical and thoracic spine but did not significantly change after age 3 in the lumbar spine.

CONCLUSIONS

In conclusion, closure of the NCS differed among the cervical, thoracic, and lumbar spine regions. The NCS reached closure in males before females even though females mature faster and reach skeletal maturity sooner than males. However, it is not determined whether the continued open NCS in females to a later age may be a factor in their increased rate of scoliosis.

Morphometric Analysis of Vertebral Growth Using Magnetic Resonance Imaging in the Normal Skeletally Immature Spine

STUDY DESIGN

Morphometic analysis of the thoracic and lumbar pedicle, vertebral body, and spinal canal in the normal infantile and juvenile patients using magnetic resonance imaging (MRI).

OBJECTIVE

To 3-dimensionally characterize the growth of the vertebral column in vivo and define the accurate dynamic growth rate of the normal immature spine.

SUMMARY OF BACKGROUND DATA

There is a relationship between growth of the spine and the development of spinal deformity. Currently available information regarding vertebral column growth is remarkably limited and poorly defined. The detailed morphologic research is needed to obtain accurate data with regard to growth of the vertebra, including coronal, sagittal, and axial growth information for normal states.

METHODS

A total of 34 pediatric patients with a normal straight spine who had MRI from thoracic vertebra 1 to lumbar vertebra 5 were assigned to 3 groups: infantile group (n = 11), 0 to 3 years of age; juvenile-young group (n = 16), 4 to 7 years of age; and juvenile-old group (n = 7), 8 to 10 years of age. True transverse and midsagittal MRI images were used for pedicle (width and length), vertebral body (height, depth and width), and spinal canal area measurements.

RESULTS

The mean increase of the pedicle width and length was 0.7 mm (16%) and 3.2 mm (18%) from the infantile to the juvenile-young, and was 0.9 mm (15%) and 2.2 mm (11%) through the juvenile-old group. The mean increase of the vertebra body width, depth, and height were 3.6 mm (15%), 4.5 mm (27%), and 3.1 mm (27%), respectively, from the infantile to the juvenile-young, and were 2.9 mm (10%), 1.9 mm (9%) and 2.1 mm (15%), respectively, through the juvenile-old group. The mean increase of the spinal canal area was 41 mm (19%) from the infantile to the juvenile-young and was only 1.8 mm (0.7%) through the juvenile-old group.

CONCLUSION

The current study established the growth of the pedicle, spinal canal, and vertebral body in vivo in a sample of normal pediatric subjects. The vertebral growth rate in the infantile and the juvenile-young period was significantly greater than that in the juvenile-old period. Spinal canal growth is associated with the growth of the pedicle width and has little growth after the juvenile-young period. Pedicle screw fixation would be unlikely to influence the size of the spinal canal after the early juvenile period, but may disturb the pedicle growth in length.

Surgical outcomes and complications of posterior hemivertebra resection in children younger than 5 years old

Background

There have been many reports on posterior hemivertebra resection. However, there were few articles in very young cases. This is a clinical retrospective study to evaluate the complications and efficacy of posterior hemivertebra resection in very young cases.

Methods

From January 2003 to January 2012, 39 consecutive cases of congenital scoliosis with hemivertebra were retrospectively investigated in our hospital, including 18 females and 21 males, aged from 21 to 65 months old (average 42.4 months). All the cases underwent posterior hemivertebra resection with transpedicular instrumentation. Clinical charts and radiographs of spine were retrospectively reviewed to record complications and outcomes postoperatively and at the latest follow-up.

Results

Mean operation time was 186.4 min (90–280 min) with average blood loss of 306.6 (100–700) ml. The total number of hemivertebrae resected was 43, including one hemivertebra in 35 cases and two hemivertebrae in 4 cases. The mean number of fused segments was 3.4, including 22 cases (56.4 %) with bisegmental fusion and 4 cases with mesh cage. Average follow-up period was 5.4 (3 to 11) years. There was a mean improvement rate of 83.6 % in the segmental scoliosis from 38.4° before surgery to 6.3° after operation and a mean improvement rate of 81.9 % in segmental kyphosis from 17.1° to 3.2° over the same time. The spontaneous correction rates of the compensatory cranial curve and compensatory caudal curve were 65.7 and 66.9 %, respectively. There were three complications (two cases),one pedicle fractures, one rod breakages, and one additional surgery for curve progression. Besides these, two additional surgeries (two cases) were performed to remove the instrumentation for pedicle elongation in the follow-up. There was no neurological complication.

Conclusions

Posterior hemivertebra resection with transpedicular instrumentation is a safe and effective procedure in very young congenital scoliosis cases. Earlier surgeries can achieve short fusion and save more mobile segments. However, complications associated with implants and spinal growth still remain major concerns.

Does pedicle screw fixation under age 5 cause spinal canal narrowing? A CT study with minimum 5 years follow-up

PURPOSE

The aim of this retrospective study was to evaluate the changes in the vertebral body and spinal canal area in a group of patients who had pedicle screw fixation under age 5 for the treatment of congenital spinal deformity at least 5 year follow-up.

METHODS

11 patients who had been operated due to spinal deformity under age 5 with who had a CT examination at least 5 years after the initial operation were included in the study. All patients underwent hemivertebrectomy and transpedicular fixation procedures at an average age of 3.18 years (range 2-5 years). All had preoperative CT to evaluate the congenital deformities. Measurements were done at the instrumented vertebrae as well as the un-instrumented ones above and below them to evaluate; vertebral body parameters, pedicle parameters and spinal canal area of upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), upper adjacent un-instrumented vertebra and lower adjacent un-instrumented vertebra.

RESULTS

The average follow-up was 7.2 (range 5-12) years. Six of the patients were over age 10 during the final CT examination while 5 were at age 7. Female-to male ratio was 8-3. Measurement of all the parameters in 22 instrumented and 22 non-instrumented segments showed a proportional increase rather than a decrease at each segment. The percentage of canal area growth at UIV and LIV was 21 and 17.5 %, respectively.

CONCLUSION

Pedicle screw instrumentation has no adverse effect on further spinal body, pedicle and canal growth and does not result in iatrogenic spinal canal stenosis.

Surgical outcomes by age at the time of surgery in the treatment of congenital scoliosis in children under age 10 years

BACKGROUND CONTEXT

There is little information regarding the surgical outcomes with regard to the timing of surgery in children under age 10 years for congenital scoliosis with a long-term follow-up.

PURPOSE

The purpose of this study was to compare the surgical outcomes for congenital scoliosis in children 6 years or older but less than 10 years of age.

STUDY DESIGN

This is a retrospective study.

PATIENT SAMPLE

Eighteen congenital scoliosis patients under age 10 years at the time of surgery were treated by posterior hemivertebra resection and bilateral pedicle screw fixation.

OUTCOME MEASURES

Outcome measures are radiological outcomes (plain radiographs and computed tomography) and complications.

METHODS

Eighteen congenital scoliosis patients (n=18) under age 10 years at the time of surgery were treated by posterior hemivertebra resection and bilateral pedicle screw fixation. These cases were retrospectively studied and had a minimum of 7-year follow-up. We assigned patients into two groups: Group 1 (n=9) patients who had surgery before 6 years of age and Group 2 (n=9) those who had surgery after 6 years of age.

RESULTS

The groups were not found to be statistically different in operative time, blood loss, and follow-up period. In the Group 1, the mean Cobb angle of the main curve was 32.4° before surgery, 6.4° after surgery, and 9.1° at last follow-up. In the Group 2, the mean Cobb angle of the main curve was 36.5° before surgery, 10.4° after surgery, and 14.5° at last follow-up. There was significantly better deformity correction of main curve immediate postoperatively and at last follow-up in Group 1. No significant difference was observed in growth rate of the vertebral body and spinal canal parameters comparing the two groups at the vertebra with or without screws. There was no crankshaft phenomena, no clinical or radiographic features suggestive of spinal stenosis during follow-up, and no major vascular or neurological complications related to the pedicle screws in either group.

CONCLUSIONS

In congenital scoliosis patients, posterior hemivertebra resection after pedicle screw fixation before the age of 6 years had significantly better deformity correction and did not cause a negative effect on the growth of vertebral body or spinal canal compared with the group treated after 6 years of age. Therefore, early surgical correction of a congenital hemivertebra in children under 6 years of age, before structural changes occur, effectively achieves a more satisfactory correction without causing iatrogenic spinal stenosis or neurologic complications compared with children older than 6 years but under 10 years of age.

Assessment of the treatment response of spinal meningiomas after radiosurgery focusing on serial MRI findings

PURPOSE

This study evaluated the response of spinal meningiomas to treatment, by monitoring changes in magnetic resonance imaging (MRI) findings after stereotactic radiosurgery (SRS).

MATERIALS AND METHODS

Serial follow-up MRIs of 11 patients with spinal meningiomas who underwent SRS were retrospectively reviewed. Changes in tumor volume, T2 signal intensity (T2SI), and contrast enhancement were evaluated.

RESULTS

The mean MRI follow-up period was 46.9 months (range 13-108 months). The local tumor control rate was 100 % in overall tumor volume, although boost SRS was performed for marginal recurrence in case 8 and rapid decompression in case 5. Seven tumors showed decreased T2SI. Each of the remaining four tumors showed variable T2SIs. In most tumors, the enhancement patterns did not change. Two of three patients with en plaque type meningiomas showed increased intramedullary T2SI, thought to be due to compressive myelopathy and peritumoral edema.

CONCLUSIONS

SRS resulted in successful local tumor control in all patients, although the follow-up period was not long. Changes in T2SI and contrast enhancement patterns of the tumors were evaluated on serial MRI. In addition, close follow-up with MRI is desirable to monitor intramedullary signal changes in cases of spinal meningiomas with a wider contact area with the spinal cord.

Role of magnetic resonance imaging in predicting surgical outcome in patients with cervical spondylotic myelopathy

STUDY DESIGN

Ambispective, retrospective cohort study from prospectively collected data.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic myelopathy is the commonest cause of spinal cord impairment in the elderly population worldwide. Although magnetic resonance imaging (MRI) is the primary imaging modality for confirming the diagnosis, its role in predicting surgical outcome remains unclear.

METHODS

Two hundred seventy-eight patients with 1 or more clinical signs of myelopathy were enrolled; and they underwent decompression surgery. Complete baseline clinical and MRI data were available for 102 patients. MRI parameters measured included presence/absence of signal change on T1 and T2, T2 signal quantitative factors, and anatomical measurements. A dichotomized postoperative modified Japanese Orthopedic Association (mJOA) score at 6 months was used to characterize patients with mild myelopathy (≥16) and those with substantial residual neurological impairment (<16). Univariate analysis assessed the relationship between baseline parameters and outcome. Multivariate logistic regression was conducted after a conceptual division of variables into 3 groups: T1 signal analysis, T2 signal analysis, and anatomical measurements.

RESULTS

Baseline mJOA (P<0.001; odds ratio [OR]=1.644, 95% confidence interval [95% CI]: 1.326-2.037), maximum canal compromise (MCC) (P=0.0322; OR=0.965, 95% CI: 0.934-0.997), T2 hyperintensity region of interest area (P=0.0422; OR=0.67; 95% CI: 0.456-0.986), and sagittal extent (P=0.026; OR=0.673; 95% CI: 0.475-0.954) were significantly associated with outcome univariately. The final model was comprised of T1 hypointensity (P=0.029; OR=0.242; CI: 0.068-0.866), MCC (P=0.005; OR=0.940; CI: 0.90-0.982) and baseline mJOA (P<0.001; OR=1.743; CI: 1.353-2.245), yielding an area under the receiver operating characteristic curve (AUC) of 0.845.

CONCLUSION

Baseline mJOA is a strong predictor of postsurgical outcome in cervical spondylotic myelopathy at 6 months. However, a model inclusive of MCC and T1 hypointensity assessment provides superior predictive capacity. This suggests that MRI analysis has a significant role in predicting surgical outcome.

LEVEL OF EVIDENCE

3.

Increased flow signal in compressed segments of the spinal cord in patients with cervical spondylotic myelopathy

STUDY DESIGN

Prospective controlled trial.

OBJECTIVE

To describe a newly found increased flow signal in phase-contrast magnetic resonance imaging observed in compressed segments of the spinal cord in patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Derangement of cerebrospinal fluid movement in the spine is a well-known cause of syringomyelia. However, its possible role in CSM has not been studied well, despite the fact that similar derangement takes place in CSM.

METHODS

In a consecutive series of 57 patients with CSM, cardiac-gated phase-contrast magnetic resonance imaging was analyzed. The amplitude of the flow signal obtained in the compressed segment of the spinal cord was compared with that obtained in the lesion-free C2 segment. It was also compared with controls obtained from 10 healthy volunteers. We also studied whether the amplitude was correlated with the severity of cervical canal stenosis, neurological symptoms, indication of surgery, and the presence of intramedullary high-intensity signal on T2-weighted images. In 33 patients who underwent decompression surgical procedures, we compared the amplitude of the flow signal between the preoperative and the postoperative study.

RESULTS

Increased flow signal on phase-contrast study was seen in compressed segments of the spinal cord in 36 (63%) patients. The mean amplitude of the signal in the compressed segment was 0.64 ± 0.06 cm/s, whereas that in the C2 segment was 0.27 ± 0.01 and that in the controls was 0.28 ± 0.01. The flow signal linearly increased as the severity of canal stenosis increased. It significantly correlated with the symptom of upper-extremity dysesthesia, and the indication of surgery in these patients. The mean amplitude of the signal tended to be higher in those with intramedullary high-intensity signal than in those without. After decompression surgery, the increased flow signal was markedly diminished, and returned to a level comparable with the controls.

CONCLUSION

Phase-contrast imaging demonstrated increased flow signal in compressed segments of the spinal cord in a majority of patients with CSM. This suggests a possible role played by derangement of cerebrospinal fluid movement in CSM. It also suggests potential usefulness of phase-contrast study in the management of patients with CSM.

LEVEL OF EVIDENCE

2.

Comparison of the safety and efficacy of anterior 'skip' corpectomy versus posterior decompression in the treatment of cervical spondylotic myelopathy

Background

The aim of this study was to compare the therapeutic effects of anterior ‘skip’ corpectomy with posterior decompression for treating four-level cervical spondylotic myelopathy.

Methods

Operation time and blood loss during the operation for the anterior and posterior approach groups were recorded. Patients were examined with cervical lateral radiography before and after the operation to measure Cobb's angle and postoperatively to monitor bony fusion. Surgery-, instrumentation-, and graft-related complications were assessed and recorded.

Results

The surgical aspects of both anterior ‘skip’ corpectomy and posterior decompression went smoothly, with mean durations of 2.5 and 2.1 h, respectively, and mean blood loss volumes of 250 and 380 mL, respectively. In the anterior approach group, the complications included axial pain in five cases and transient hoarseness in two. Radiography revealed titanium mesh subsidence in two cases and plate or screw dislodgement in one case. In the posterior approach group, C5 nerve root palsy was present in 2 patients, axial pain in 15, and cerebrospinal fluid leakage in 3. The mean Japanese Orthopaedic Association scores showed that the recovery rate was significantly higher in the anterior approach group than in the posterior approach group (p < 0.05).

Conclusions

‘Skip’ corpectomy has comparable safety and better efficacy than posterior decompression in the treatment of four-level cervical spondylotic myelopathy.

Effect of dual screws across the vertebral neurocentral synchondrosis on spinal canal development in an immature spine: a porcine model

BACKGROUND

Questions remain as to the effect of pedicle screws on spinal canal development in young children. The purpose of this study was to determine the effects of unilateral placement of dual screws across the neurocentral synchondrosis on spinal canal development as assessed with histological analysis and measurement of the canal dimensions in an immature pig model.

METHOD

Twenty-seven one-month-old pigs were assigned to two groups on the basis of the surgical approach used to place unilateral double screws that did or did not cross the neurocentral synchondrosis. In one group, sixteen pigs underwent a posterior approach from T7 to T14 and were divided into four subgroups: no screws (without screw fixation), short screws (dual pedicle screws that did not cross the neurocentral synchondrosis), long screws (dual pedicle screws that crossed the neurocentral synchondrosis), and screw removal (long dual pedicle screws that were removed at six weeks postoperatively). In the other group, eleven pigs underwent an anterior approach, with double vertebral body screws placed via thoracotomy. These animals were divided into two subgroups: short screws (dual vertebral body screws that did not cross the neurocentral synchondrosis) and long screws (dual vertebral screws that crossed the neurocentral synchondrosis). All animals were killed at seventeen weeks. The total area, width, and depth of the spinal canal were measured on axial computed tomography (CT) images. Quantitative histological analysis was performed to measure the rate of neurocentral synchondrosis closure.

RESULTS

Use of unilateral double pedicle screws across the neurocentral synchondrosis through a posterior approach resulted in 97% neurocentral synchondrosis closure with a 20% decrease in the canal area and a 15% decrease in the canal depth. Use of unilateral double vertebral body screws across the neurocentral synchondrosis through an anterior approach resulted in 71% neurocentral synchondrosis closure with a 15% decrease in the canal area and an 8% decrease in the canal width.

CONCLUSIONS

Unilateral double pedicle screws crossing the neurocentral synchondrosis adversely affected spinal canal growth in immature pigs.

CLINICAL RELEVANCE

Pedicle screws should be used with caution in very young children, and a delay in surgical treatment until they are older should be considered.

Preoperative spinal cord damage affects the characteristics and prognosis of segmental motor paralysis after cervical decompression surgery

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To test the hypothesis that preoperative spinal cord damage affects postoperative segmental motor paralysis (SMP).

SUMMARY OF BACKGROUND DATA

SMP is an enigmatic complication after cervical decompression surgery. The cause of this complication remains controversial. We particularly focused on preoperative T2-weighted high signal change (T2HSC) on magnetic resonance imaging in the spinal cord, and assessed the influence of preoperative T2HSC on SMP after cervical decompression surgery.

METHODS

A retrospective review of 181 consecutive patients (130 males and 51 females) who underwent cervical decompression surgery was conducted. SMP was defined as development of postoperative motor palsy of the upper extremities by at least 1 grade in manual muscle testing without impairment of the lower extremities. The relationship between the locations of T2HSC in preoperative magnetic resonance imaging and SMP and Japanese Orthopedic Association score was investigated.

RESULTS

Preoperative T2HSC was detected in 78% (142/181) of the patients. SMP occurred in 9% (17/181) of the patients. Preoperative T2HSC was not a significant risk factor for the occurrence of SMP (P = 0.682). However, T2HSC significantly influenced the severity of SMP: the number of paralyzed segments increased with an incidence rate ratio of 2.2 (P = 0.026), the manual muscle score deteriorated with an odds ratio of 8.4 (P = 0.032), and the recovery period was extended with a hazard ratio of 4.0 (P = 0.035). In patients with preoperative T2HSC, Japanese Orthopaedic Association scores remained lower than those in patients without T2HSC throughout the entire period including pre- and postoperative periods (P < 0.001).

CONCLUSION

Preoperative T2HSC was associated with worse severity of SMP in patients who underwent cervical decompression surgery, suggesting that preoperative spinal cord damage is one of the pathomechanisms of SMP after cervical decompression surgery.

LEVEL OF EVIDENCE

3.

Systematic review of magnetic resonance imaging characteristics that affect treatment decision making and predict clinical outcome in patients with cervical spondylotic myelopathy

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine whether there are magnetic resonance imaging (MRI) characteristics in patients with cervical spondylotic myelopathy that affect treatment decisions or predict postsurgical outcomes or adverse events.

SUMMARY OF BACKGROUND DATA

Although the role of MRI in confirming the clinical diagnosis of cervical spondylotic myelopathy and directing surgical management is well established, its potential value as a prognostic tool is largely unknown.

METHODS

A systematic search was conducted using PubMed and the Cochrane Collaboration Library for articles published between January 1, 1956, and November 20, 2012. The overall body of evidence with respect to each clinical question was determined on the basis of precepts outlined by the Grading of Recommendation Assessment, Development and Evaluation Working Group and recommendations made by the Agency for Healthcare Research and Quality.

RESULTS

The initial search yielded 268 citations. Twenty publications met all inclusion criteria and were included in the review. Three of these assessed MRI predictors of clinical deterioration in the case of conservative treatment and 17 evaluated MRI anatomic or cord characteristics that could predict surgical outcome or adverse events. There is low evidence suggesting that a high signal intensity (SI) grade on T2WI is not associated with patient deterioration during conservative treatment. High SI grade on T2WI, along with compression ratio and canal diameter, was not an important predictor of outcome. There is low evidence identifying number of high SI segments on T2WI, low SI segments on T1WI, combined T1/T2 SI, and SI ratio as important negative predictors of surgical outcome.

CONCLUSION

On the basis of this review and on low-quality evidence, we have identified 3 important negative predictors of surgical outcome: number of high SI segments on T2WI, combined T1/T2 signal change, and SI ratio.EVIDENCE-BASED CLINICAL RECOMMENDATIONS:

RECOMMENDATION 1

We suggest that when clinically feasible, surgeons rely on MRI to confirm the diagnosis of CSM and rely on clinical history and examination to determine progression and severity of disease.

OVERALL STRENGTH OF EVIDENCE

Low.

STRENGTH OF RECOMMENDATION

Weak.

RECOMMENDATION 2

T2 signal may be a useful prognostic indicator when used in combination with low SI change on T1WI, or as a ratio comparing compressed with noncompressed segments, or as a ratio of T2 compared with T1WI. We suggest that if surgeons use MRI signal intensity to estimate the risk of a poor outcome after surgery, they use high SI change on T2WI in combination with other signal intensity parameters, and not in isolation.

OVERALL STRENGTH OF EVIDENCE

Low. StrENGTH OF RECOMMENDATION: Weak.

X-Ray assessment of the effect of pedicle screw on vertebra and spinal canal growth in children before the age of 7 years

PURPOSE

To determine the reliability of pedicle screws placed in children younger than 7 years of age, and to evaluate the effect of pedicle screw insertion on further growth of the vertebra and spinal canal.

METHODS

A retrospective study of 35 consecutive patients through Jan 2003-Dec 2010 for congenital scoliosis in <7 years children was performed at one spine center. Patients undergoing pedicle screw instrumentation of at least two levels, which had been followed-up for at least 24 months were included. Measurements were performed in instrumented and adjacent non-instrumented levels. The effect of pedicle screw insertion on further growth was evaluated.

RESULTS

The average age at surgery was 4.4 year (53 months, range, 23-84 months). 190 segments in 35 patients met the inclusion criteria. 77 segments had no screws and 113 had at least one screw. There was a significant difference between the pre-operative and final follow-up values of the measurement of spinal canal and vertebral body parameters (P < 0.001). No significant difference existed between growth rates of vertebral bodies and the sagittal diameters of spinal canal with or without screws. The growth rates of vertebral bodies in lumbar spine were higher than in thoracic spine in both instrumented and adjacent groups.

CONCLUSION

Pedicle screw instrumentation does not cause a retardation effect on the development of vertebral bodies and the spinal canal in children at an early age. It is a safe and reliable procedure to achieve a stable fixation.

Desmoplastic fibroma of the spine causing severe mediastinal compression and brachial plexus encasement: report of 2 cases

Desmoplastic fibroma (DF) is a rare bone tumor that accounts for about 0.1%-0.3% of all bone tumors. It is typically characterized as slow growing, but in rare cases it can proliferate extensively and exhibit locally aggressive characteristics. It is found most commonly in the appendicular skeleton and rarely in the axial skeleton. The authors present the cases of 2 women in their 20s with DF originating from the cervicothoracic spine. Both tumors intimately involved the brachial plexus and caused significant impingement of the mediastinum resulting in cardiopulmonary compromise. Both patients underwent hemiclamshell thoracotomies for tumor resection, and in both cases subtotal resection was performed given the encasement of the brachial plexus. Although DF is a benign process, it can be locally aggressive and proliferate at extensive rates. The authors describe these 2 cases, review the literature, and discuss management.

Assessment of spinal cord compression by magnetic resonance imaging--can it predict surgical outcomes in degenerative compressive myelopathy? A systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

We sought to conduct a systematic review to examine the role of magnetic resonance imaging in predicting outcomes after surgery and to evaluate the evidence currently available critically.

SUMMARY OF BACKGROUND DATA

Degenerative compressive myelopathy is a common clinical problem associated with adverse health outcomes. Although a number of studies have investigated the association between preoperative magnetic resonance imaging characteristics and outcomes after surgery for degenerative compressive myelopathy, the conclusions of these studies have often yielded differing results.

METHODS

Articles examining the predictive value of magnetic resonance imaging were obtained from MEDLINE, EMBASE, and PubMed databases (1980-2011). Thirty publications that met the inclusion criteria were reviewed. Two reviewers independently assessed each study regarding the level of evidence (using the criteria proposed by Sackett) and methodological quality based on revised Cochrane quality assessment checklist.

RESULTS

Three excellent, 1 good, and 10 poor quality studies assessed cord compression--transverse area (4), compression ratio (5), and anteroposterior diameter (1). Relationship between signal intensity (SI) changes and surgical outcomes were reviewed by 28 studies--8 excellent, 9 good, and 13 poor quality studies. SI changes within the spinal cord included the presence of SI on T2-weighted image (WI) (17), area of SI on T2WI (8), degree of SI on T2WI (5), presence of SI on both T1-/T2WI (2), SI ratio on T2WI (2), and the position of SI on T2WI (1).

CONCLUSION

Based on a combination of excellent and good quality studies, transverse area correlates with recovery ratio but not with postoperative functional score assessed by Japanese Orthopaedic Association/modified Japanese Orthopaedic Association scores. SI changes defined by (1) its presence on T2WI, (2) its extent (focal or multisegmental), (3) its brightness, and (4) its presence on both T1-/T2WI can predict surgical outcomes in degenerative compressive myelopathy.

Quantitative analysis of the closure pattern of the neurocentral junction as related to preexistent rotation in the normal immature spine

BACKGROUND CONTEXT

The normal spine is not a symmetrical structure. In recent studies, we demonstrated the presence of an axial rotational pattern that is similar to what is seen in the most prevalent curve patterns in idiopathic scoliosis at different ages. This suggests that if the spine starts to decompensate into scoliosis, it follows this preexistent rotational pattern. In scoliosis, the neurocentral junctions (NCJs) close asymmetrically, which leads to a different pedicle morphology in the convexity and concavity of the curve. The present study aimed to establish at which age the NCJ closes in different regions of the spine, whether it closes asymmetrically in the nonscoliotic spine as well and whether the closure pattern is related to the earlier demonstrated preexistent rotation.

PURPOSE

To evaluate the closure pattern and surface area of the left and right NCJs throughout the normal immature spine in relation to the preexistent spinal rotation at different ages.

STUDY DESIGN

Retrospective cohort study using a systematic, semiautomatic analysis.

PATIENT SAMPLE

Computed tomography (CT) scans of the thorax and abdomen of 199 nonscoliotic children (0-16 years old) were systemically analyzed. CT scans had been obtained for several reasons unrelated to this study, for example, recurrent respiratory infections, malignant disease (not involving the spine), or work up before bone marrow transplantation. Scans were categorized according to the criteria of the Scoliosis Research Society into infantile (0-3 years old), juvenile (4-9 years old), and adolescent (10-16 years old) age cohorts.

OUTCOME MEASURES

Closure, absolute surface area, and the angle between the longitudinal axis of the left and right NCJ and preexistent vertebral rotation at each spinal level.

METHODS

Transverse CT slices were systemically analyzed for closure and asymmetry of the absolute area of 4,992 NCJs from spinal levels T2-L5. The outcome measures were analyzed semiautomatically using custom-made software developed at our institution (ImageXplorer; Image Sciences Institute). Inter- and intraobserver reliabilities were calculated.

RESULTS

For all subjects, the entire thoracic area was available. Complete scans down to L5 of the lumbar spine were available in 43 cases. Closure of the NCJs was first observed in the lumbar spine, then in the high thoracic spine, and finally in the mid- and low thoracic spine. Closure occurred asymmetrically, left-right predominance depended on the age. In the mid- and low thoracic spine, the surface areas of the right NCJs were larger at the infantile age, whereas at the juvenile age the areas of the left NCJs were larger. This corresponded to the spine's preexistent rotation. Rotation of the high thoracic vertebrae was to the left in all age cohorts. Rotation in the mid- and low thoracic spine was to the left in the infantile cohort but reversed to the right in the juveniles and even more so in the adolescents. The lumbar spine was rotated to the left at the infantile age and not significantly rotated at the juvenile and adolescent ages. Orientation of the NCJs in relation to the vertebraes' longitudinal axis was symmetrical, not dependent on age, and more transverse at the midthoracic levels than at other spinal levels.

CONCLUSIONS

This study focuses on the asymmetry and the regional pattern of closure of the NCJs at different ages. It suggests that preexistent rotation of the spine is related to the asymmetrical closure of the NCJs. Whether the asymmetry is the cause of or is caused by the preexistent rotation cannot be derived from this study.

Neurogenic bladder associated with pure cervical spondylotic myelopathy: clinical characteristics and recovery after surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

To examine the prevalence of lower urinary tract symptoms (LUTS) and neurogenic bladder (NB), and surgical outcomes in pure cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

The inclusion of various types of cervical diseases, NB, and no obvious definition of NB provided the wide range of NB prevalence frequency among previous reports.

METHODS

Of the 220 operated patients with cervical myelopathy, 54 were selected by excluding other cervical and/or concomitant diseases contributing to LUTS. All patients with LUTS were referred to urologists and recommended to undergo urodynamic study (UDS). The presence of NB was judged by abnormal findings of UDS according to the most recent criteria and a congruity between LUTS and the course of cervical myelopathy. Patients were divided into 4 groups: no symptoms, positive symptoms without UDS examination, positive symptoms with positive NB, and positive symptoms with negative NB. Evaluation scores were compared among the groups before and after surgery.

RESULTS

There were no particular LUTS in NB patients. Prevalence of LUTS was 53.7% and that of NB was at least 20.4% in the patients with pure cervical spondylotic myelopathy. The scores of all 4 groups improved after surgery (P < 0.05); however, the recovery rate of NB group (47.1%) was the worst among the groups (no-symptoms group, 69.3%; negative-NB group, 53.5%; and positive symptoms without UDS group, 57.1%). Preoperative part scores showed no difference among the groups, whereas NB group demonstrated lower scores in finger and lower extremity postoperatively. A post hoc analysis confirmed a significantly poorer recovery rate related to the NB group only in the lower extremities.

CONCLUSION

This study is the first to describe the prevalence of LUTS and NB according to the most recent criteria in patients with pure cervical spondylotic myelopathy, which demonstrated that neurological functions in NB patients may recover; however, the extent will be limited to two-thirds of those in patients with no-NB; moreover, the remaining symptoms derive from poor lower limb function.

Radiograph-based study of gender-specific vertebral area gain in healthy children and adolescents as a function of age, height, and weight

This study reports gender-specific vertebral area gain data from children and adolescents. Vertebral area was measured on lateral and anteroposterior thoracic and lumbar spine radiographs from 100 female and 100 male subjects aged 7-28 yr. T9, T11, T12, L1, and L2 X-ray area calculation was based on calculation of the area of the geometric figure of a trapezoid whose 2 nonparallel sides were equal in length, taking account of the waisted shape of the vertebrae. Both the boys and girls of our study population showed statistically significant dependence (p<0.001) of vertebral area gain on chronologic age, height, and weight right through the end of puberty, and especially so up to age 15 yr. However, height and weight were clearly better predictors of lateral and anteroposterior vertebral area gain than was chronologic age. Once vertebral growth is complete by age 18 yr or so, the lateral vertebral areas of the male subjects-regardless of body weight and height-are, on average, 25% larger, and the anteroposterior areas up to 30% larger than those of their female counterparts. After adjusting for chronologic age, height, and weight however we did not find significant differences, between gender, in vertebral area of male and female subjects, neither among children younger than 11 yr nor adolescents ages of 12-14 yr and young adults older than 18 yr.

The effect of pedicle screw insertion at a young age on pedicle and canal development

STUDY DESIGN

A longitudinal case study.

OBJECTIVE

To determine whether pedicle screws placed in an immature spine exert effect on the continued growth of the vertebral body.

SUMMARY OF BACKGROUND DATA

Pedicle screws have revolutionized surgical treatment of spinal deformities by allowing a mode of secure fixation that provides consistently better correction rates in adults and adolescents. In the young child, however, the trajectory of pedicle screws takes them through an open physis: the neurocentral cartilage. There exists little information regarding the possible effect of pedicle screws inserted at a young age on further development of the spine and the spinal canal.

METHODS

Patients undergoing pedicle screw instrumentation of at least 2 levels before the age of 5 years (60 mo) for the first time for any diagnosis and who had been followed for at least 24 months were included. Measurements were performed in instrumented and adjacent noninstrumented levels without visible deformity in pre- and postoperative cross-sectional images and compared using statistical methods.

RESULTS

Ninety segments in 15 patients met the inclusion criteria (average age at instrumentation 46.3 mo [range, 29-60 mo]). Forty segments had no screws and 50 had at least 1 screw. Pedicle length and vertebral body diameter had significantly increased in both groups, whereas spinal canal parameters did not change significantly. No significant difference was observed between the growth rates in levels with or without screws in pedicle length, vertebral body diameter, or spinal canal parameters (anterior-posterior and interpedicular diameters, and area).

CONCLUSION

Pedicle screw instrumentation performed before the age of 5 years does not cause a negative effect on the growth of pedicles, the transverse plane of the vertebral body, or the spinal canal. It can be safely performed in the treatment of deformity in this age group.

Clinical significance of MRI/(18)F-FDG PET fusion imaging of the spinal cord in patients with cervical compressive myelopathy

PURPOSE

(18)F-FDG PET is used to investigate the metabolic activity of neural tissue. MRI is used to visualize morphological changes, but the relationship between intramedullary signal changes and clinical outcome remains controversial. The present study was designed to evaluate the use of 3-D MRI/(18)F-FDG PET fusion imaging for defining intramedullary signal changes on MRI scans and local glucose metabolic rate measured on (18)F-FDG PET scans in relation to clinical outcome and prognosis.

METHODS

We studied 24 patients undergoing decompressive surgery for cervical compressive myelopathy. All patients underwent 3-D MRI and (18)F-FDG PET before surgery. Quantitative analysis of intramedullary signal changes on MRI scans included calculation of the signal intensity ratio (SIR) as the ratio between the increased lesional signal intensity and the signal intensity at the level of the C7/T1 disc. Using an Advantage workstation, the same slices of cervical 3-D MRI and (18)F-FDG PET images were fused. On the fused images, the maximal count of the lesion was adopted as the standardized uptake value (SUV(max)). In a similar manner to SIR, the SUV ratio (SUVR) was also calculated. Neurological assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy.

RESULTS

The SIR on T1-weighted (T1-W) images, but not SIR on T2-W images, was significantly correlated with preoperative JOA score and postoperative neurological improvement. Lesion SUV(max) was significantly correlated with SIR on T1-W images, but not with SIR on T2-W images, and also with postoperative neurological outcome. The SUVR correlated better than SIR on T1-W images and lesion SUV(max) with neurological improvement. Longer symptom duration was correlated negatively with SIR on T1-W images, positively with SIR on T2-W images, and negatively with SUV(max).

CONCLUSION

Our results suggest that low-intensity signal on T1-W images, but not on T2-W images, is correlated with a poor postoperative neurological outcome. SUV(max) of lesions showing increased signal intensity and SUVR measured on fusion MRI/PET scans are more sensitive parameters for predicting clinical outcome than signal intensity on the MRI scan.

Neurocentral synchondrosis screws to create and correct experimental deformity: a pilot study

BACKGROUND

Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis (NCS) can produce asymmetric growth of the synchondrosis to create scoliosis in an immature animal model.

QUESTIONS/PURPOSES

We asked whether a preexisting experimentally created scoliosis could be limited and corrected by modulating the growth of the faster-growing NCS by a similar method.

METHODS

Nine 1-month-old pigs were assigned to each of three groups: (1) a sham group in which three animals received a sham operation but without a pedicle screw fixation; (2) an experimental group with double right pedicle screws placed across the NCS from T7 to T14 (scoliosis-untreated); and (3) an experimental group treated in the same way except a second set of double pedicle screws was placed in the left pedicles 6 weeks after the screws were placed on the right (scoliosis-treated). All animals were euthanized at 17 weeks, and radiographs and axial CT images of the spine were obtained.

RESULTS

A scoliotic curve was not seen in any of the animals in the sham group, in three of three in the scoliosis-untreated group with an average of 34°, and in three of three in the scoliosis-treated group with an average of 20°. In comparison to the scoliosis-untreated group, the second set of pedicle screws produced a 41% correction of the scoliosis.

CONCLUSIONS

We found the pedicle screw inhibited the overgrowth of the NCS to prevent further curve progression and obtained some correction of the deformity. The NCS screw epiphysiodesis can create and reverse scoliosis in an immature pig model.