Preoperative assessment of idiopathic scoliosis in adolescent and young adult with three-dimensional T2-weighted spin-echo MRI

The significance of cerebrospinal fluid dynamics in adolescent idiopathic scoliosis using time-SLIP MRI

Adolescent idiopathic scoliosis (AIS) affects approximately 3% of the global population. Recent studies have drawn attention to abnormalities in the dynamics of the CSF as potential contributors. This research aims to employ the Time-Spatial Labeling Inversion Pulse (Time-SLIP) MRI to assess and analyze cerebrospinal fluid (CSF) dynamics in AIS patients. 101 AIS patients underwent Time-SLIP MRI. Images were taken at the mid-cervical and craniocervical junction regions. The sum of the maximum movement distances of CSF on the ventral and dorsal sides of the spinal canal within a single timeframe was defined and measured as Travel Distance (TD). Correlations between TD, age, Cobb angle, and Risser grade were analyzed. TD comparisons were made across Lenke classifications. TD for all patients was a weak correlation with the Cobb angle (r = - 0.16). Comparing TD between Lenke type 1 and 5, type 5 patients display significantly shorter TD (p < 0.05). In Risser5 patients with Lenke type 5 showed a significant negative correlation between Cobb angle and TD (r = - 0.44). Lenke type 5 patients had significantly shorter CSF TD compared to type1, correlating with worsening Cobb angles. Further analysis and exploration are required to understand the mechanism of onset and progression.

Correlation Analysis Between Computed Tomography and Magnetic Resonance Imaging for Assessing Thoracic Pedicle Morphology

OBJECTIVE

This study aimed to determine the accuracy and reliability of using magnetic resonance imaging (MRI) to characterize thoracic pedicle morphology in the normal population.

METHODS

Computed tomography (CT) and MRI datasets of 63 surgically treated patients were included in the study. Bilateral T3, T6, T9, and T12 vertebral levels were evaluated for the type of pedicle, pedicle chord length, and pedicle isthmic diameter on both MRI and CT scans. Pedicles were classified according to Sarwahi et al. into type A (normal pedicle), >4 mm cancellous channel; type B, 2-4 mm channel; type C, completely cortical channels >2 mm; and type D, <2 mm cortical bone channel.

RESULTS

Of 504 pedicles, 294 were classified as type A, 173 as type B, 24 as type C, and 13 as type D based on a CT scan. MRI had an overall accuracy rate of 92.86% for detecting type A, 96.53% for type B, and 100% for type C and type D compared with CT scans. Regarding the thoracic levels, MRI had an overall concordance of 97.98% at T3 level, 94.43% at T6 level, 98.11% at T9 level, and 99.3% at T12 level with CT readings. Comparing measurements between MRI and CT studies for pedicle isthmic diameter and pedicle chord length showed moderate to good reliability at all measured levels.

CONCLUSIONS

Pedicle measurements obtained by MRI may be used to estimate pedicle dimensions, allowing surgeons to preoperatively determine pedicle screw sizes based on MRI scans alone.

Influences of Increasing Pedicle Screw Diameter on Widening Vertebral Pedicle Size during Surgery in Spinal Deformities in Children and Adolescents without Higher Risk of Pedicle and Vertebral Breaches

BACKGROUND

A very common technique for treating spinal deformities in children and adolescents is the use of segmental screws. In order to obtain proper stability and the best possible correction, the screws must first be precisely inserted. Additional factors influencing the quality and success of the operation are the size and quality of the bone, the skills of the surgeon, and biomechanical factors, i.e., the width and length of the screws used during surgery. Our study was focused on evaluating the effect of increasing the diameter of the instrumented pedicles by pedicle screws and assessing the safety of expanding these pedicles with screws of various sizes in children with spinal deformities during the growth period, using preoperative magnetic resonance imaging and postoperative computed tomography (CT) to assess and compare preoperative size measurements from MRI to postoperative CT measurements.

METHODS

We obtained data for evaluation from the available medical records and treatment histories of patients aged 2 to 18 who underwent surgical treatment of spinal deformities in the years 2016-2023. In 230 patients (28 male and 202 female), 7954 vertebral bodies were scanned by preoperative MRI, and 5080 pedicle screws were inserted during surgery, which were then assessed by postoperative CT scan. For the most accurate assessment, patients were classified into three age groups: 2-5 years (Group 1), 6-10 years (Group 2), and 11-18 years (Group 3). In addition, we studied implant subgroups: vertebral bodies with inserted pedicles of screw sizes 5.0 mm and 5.5 mm (Group S), and pedicles of screw sizes 6.0 mm, 6.5 mm, and 7.0 mm (Group L).

RESULTS

The morphology of pedicles (Lenke classification) analyzed before surgery using MRI was 55.2% type A, 33.8% type B, 4.7% type C, and 6.3% type D. The postoperative lateral and medial breaches were noted, and these did not cause any complications requiring revision surgery. The mean pedicle diameter before surgery for T1-L5 vertebral pedicles was between 3.79 (1.44) mm and 5.68 (1.64) mm. The mean expanding diameter of pedicles after surgery for T1-L5 vertebral pedicles ranged from 1.90 (0.39) mm to 2.92 (0.28) mm, which corresponds to the extension of the pedicle diameter in the mean range of 47% (4.1)-71% (3.0). We noted that the mean vertebral pedicle expansion was 49% in Group 1, 52% in Group 2, and 62% in Group 3 (N.S.), and the mean expansion for 7.0 mm screw pedicles was 78%.

CONCLUSIONS

Our study confirms that there is a wide range of expansion of the vertebral pedicle during screw insertion (up to 78%) with a low risk of lateral or medial breaches and without an increased risk of complications. The larger the diameter of the screw inserted into the pedicle, the more the pedicle expands. Pedicle measurements by preoperative MRI may be helpful for sufficient reliability in preoperative planning.

The use of MRI in the study of patients with idiopathic scoliosis: a systematic review of the literature

Objective. To analyze the frequency of hidden neuraxial pathology in idiopathic scoliosis (IS), to substantiate the need for MRI in IS and to identify promising areas for the use of MRI in the examination of patients with IS.Material and Methods. The literature review was carried out using the PubMed and Google Scholar databases. Of the 780 papers on the research topic, 65 were selected after removing duplicates and checking for inclusion/exclusion criteria. As a result, 49 original studies were included in the analysis. Level of evidence – II.Results. According to modern literature, the main direction of using MRI in idiopathic scoliosis is the search for predictors of latent pathology of the spinal cord and craniovertebral junction. The frequency of neuraxial pathology in idiopathic scoliosis is 8 % for adolescent IS and 16 % for early IS. The main predictors of neuraxial pathology are male sex, early age of deformity onset, left-sided thoracic curve and thoracic hyperkyphosis. MRI in IS may be a useful addition to radiological diagnostic methods to identify risk factors and to study degenerative changes in the spine.Conclusion. MRI of the spine should be performed in the early stages of IS to detect latent spinal cord tethering. In type I Chiari anomalies, there is a possibility that early neurosurgery can prevent the development of scoliosis. The main signs of latent neuraxial pathology in IS are early progression of spinal deformity, left-sided thoracic curve, male gender and thoracic kyphosis over 40° according to Cobb.MRI can be used as an effective non-invasive tool in research aimed at identifying risk factors for IS, including helping to track early degeneration of intervertebral discs.

Preoperative MRI Reliably Predicts Pedicle Dimensions on Intraoperative CT Images in Structural Main Thoracic Curves in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN

A retrospective comparative study.

OBJECTIVE

The aim of this study was to compare the length and diameter of thoracic pedicles in patients with adolescent idiopathic scoliosis (AIS) as measured on preoperative magnetic resonance imaging (pMRI) to intraoperative computed tomography (iCT) scan.

SUMMARY OF BACKGROUND DATA

Optimally sized pedicle screw placement during instrumented posterior spinal fusion for AIS can maximize correction and minimize screw pullout. While iCT-guided navigation can quickly estimate screw position and size, this technology is not universally available. Many surgeons utilize pMRI, when obtained, to estimate screw sizes. Data comparing these measurements on pMRI and iCT is limited. We hypothesized that in patients with surgical magnitude AIS, pedicle length, and diameter measured on pMRI would have at least moderate reliability compared to those made on iCT images.

MATERIALS AND METHODS

The pMRI and iCT for 60 patients with structural thoracic curves who underwent posterior spinal fusion for AIS at a single center between 2009 and 2017 were analyzed. Bilateral T5-T12 vertebral levels were evaluated for pedicle chord length and pedicle isthmic diameter on both pMRI and iCT. Between-study reliability and interrater reliability was evaluated for each level of the thoracic spine.

RESULTS

There is good reliability for pedicle length [intraclass correlation coefficient (ICC)=0.8, 95% confidence interval (CI): 0.78-0.83] and diameter (ICC=0.86, 95% CI: 0.84-0.88) between pMRI and iCT. When assessed by level, T6 has the lowest reliability for length (ICC=0.52, 95% CI: 0.33-0.67) and diameter (ICC=0.55, 95% CI: 0.35-0.69). Interrater reliability ranged from moderate-to-good reliability for all pedicle measurements for both length and diameter on pMRI and iCT.

CONCLUSION

Pedicle measurements made on pMRI may be used with reasonable reliability to predict pedicle dimensions visualized on iCT, allowing surgeons to preoperatively plan pedicle screw sizes based off magnetic resonance imaging.

Cerebrospinal fluid velocity changes of idiopathic scoliosis: a preliminary study on 3-T PC-MRI and 3D-SPACE-VFAM data

OBJECTIVES

To the best of our knowledge, there is no study on 3-Tesla (3-T) phase-contrast MRI (PC-MRI) and three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE-VFAM) in the evaluation of idiopathic scoliosis. This study aimed to investigate CSF abnormalities in the scoliotic spine using 3-T PC-MRI and 3D-SPACE-VFAM techniques.

METHODS

Thirty-four patients and 14 controls were examined with spinal PC-MRI and T2-weighted 3D-SPACE-VFAM techniques. Inter- and intra-reader agreements of flow-void phenomenon on 3D-SPACE-VFAM images, and velocity values on PC-MRI data were also evaluated.

RESULTS

There are statistically significant differences between scoliosis and control groups based on the highest and mean peak velocity values on PC-MRI images (p = 0.005 and p = 0.023, respectively). The main thoracic (MT) group's highest peak CSF velocity values were higher than the control group (p = 0.022). There is a significant difference between the patient and control groups regarding flow-void phenomenon scores on 3D-SPACE-VFAM images (p = 0.036). Inter- and intra-reader agreement values related to PC-MRI velocity measurements were perfect for all PC-MRI readings. Inter- and intra-reader agreement values of the flow-void phenomenon scores were moderate.

CONCLUSIONS

Our study has led us to conclude that idiopathic scoliosis is associated with CSF flow disturbances in parallel with the literature. MRI can demonstrate these abnormalities in a non-invasive and radiation-free way.