Rotation In Adolescent Idiopathic Scoliosis Research Articles

Response to Letter to the Editor Regarding "The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up".

Response to Letter to the Editor Regarding "The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up".

Letter to the Editor RE: The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up.

Letter to the Editor RE: The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up.

The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up.

A retrospective cohort study. To evaluate the mid-term effect of intervertebral disc degeneration (DD) in adolescent idiopathic scoliosis (AIS) patients who underwent pedicle screw instrumentation (PSI) and rod derotation (RD) with direct vertebral rotation (DVR). Posterior spinal fusion is a mainstay of surgical treatment in AIS, and DVR is considered a main corrective maneuver for vertebral rotation. However, the mid-term effect of intervertebral DD after DVR is still unknown in AIS. A total of 336 vertebrae for 48 AIS patients who underwent PSI and RD with DVR were retrospectively assessed for intervertebral DD. They were divided into two groups based upon intervertebral DD, defined as Pfirmann grade more than IV. The Pfirrmann grade and modic change were evaluated at the disc above the uppermost instrumented vertebra (UIV), the disc below the lowest instrumented vertebra (LIV), and the lumbar disc levels. With the 11.6 years of mean follow-up, 41.7% (20/48) of patients exhibited DD, while modic changes were observed in 4.2% (2/48) of included patients. The disc below the LIV, L4-5, and L5-S1 were significantly shown to have an increasing trend of Pfirmann grade. The preoperative thoracic kyphosis was significantly lower in the DD group (22.0°) than in the non-DD group (31.4°) (P = 0.025) and negatively correlated with DD (r = -0.482, P = 0.018). The Pfirrmann grade of L5-S1 showed a high level of correlation with DD (r = 0.604, P < 0.001). The degenerative change at the disc below the LIV, L4-5, and L5-S1 levels was observed following PSI and RD with DVR. Thoracic hypokyphosis may negatively influence intervertebral discs in AIS patients required for deformity correction. Therefore, restoration of thoracic kyphosis is important to prevent long-term DD in AIS.

The Immediate Effect of Hanging Exercise and Muscle Cylinder Exercise on the Angle of Trunk Rotation in Adolescent Idiopathic Scoliosis

(1) Background: Semi-hanging and muscle cylinder exercises have been defined as scoliosis-specific corrective exercises. The aim of this study was to evaluate the immediate effect of muscle cylinder and semi-hanging exercises on the angle of trunk rotation in patients with adolescent idiopathic scoliosis (AIS). (2) Methods: Twenty-seven patients with AIS with a mean age of 18.6 years were retrospectively analyzed. The angle of trunk rotation (ATR) values were measured before and after performing semi-hanging and standing muscle cylinder exercises. Both exercises were performed for three to five respiratory cycles. The semi-hanging exercise was performed first, followed by the muscle cylinder exercise, in this order, in all participants. For statistical analysis, the Wilcoxon signed-rank test was used to analyze ATR changes after the exercises, and the Kruskal–Wallis test was used to compare ATR changes according to the main curve location. (3) Results: The thoracic, thoracolumbar and lumbar maximum ATR values were significantly increased after the semi-hanging exercise (p &lt; 0.001) and decreased after the muscle cylinder exercise (p &lt; 0.001). The ATR change was greater in the lumbar region than in the thoracic and thoracolumbar regions. (4) Conclusion: The results of this study of a small group of patients emphasized that one of the scoliosis-specific corrective exercises, the standing muscle cylinder exercise, improved ATR, while the other, the semi-hanging exercise, worsened ATR in patients with AIS. It is recommended that each scoliosis-specific corrective exercise be evaluated and redesigned to maximize the three-dimensional corrective effect, considering the biomechanics of the spine and the pathomechanics of scoliosis.

Rotational Changes Following Use of Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: A Long-Term Radiographic and Computed Tomography Evaluation.

A retrospective cohort study. To evaluate long-term rotational changes in the vertebrae of patients with adolescent idiopathic scoliosis (AIS) who underwent direct vertebral rotation (DVR). DVR using thoracic pedicle screws, a rotational corrective maneuver used in the surgical treatment of AIS, was introduced in 2004. Although DVR is considered to be the main axial corrective maneuver, the long-term rotational changes of vertebrae following this treatment are not well understood. A total of 135 vertebrae that underwent DVR using thoracic pedicle screws with a minimum five-year follow-up were retrospectively assessed for the vertebral rotation angle. The vertebral rotation of the apical vertebra (AV) and distal end vertebra (EV) was evaluated using the Nash-Moe scale, the rotational angle to the sacrum (RAsac), and the Aaro and Dahlborn method. The Student t test (paired means) was used for continuous variables, and the χ 2 test was used for categorical variables, as appropriate. A comparison of two and three groups used a one-way repeated measures analysis of variance, and the post hoc analysis used the Bonferroni test. The mean Nash-Moe scale of distal EV showed statistically significant differences between preoperative and postoperative values ( P =0.034) and no statistically significant difference between postoperative and last follow-up values ( P =1.000). The last follow-up RAsac of AV did not differ significantly from the preoperative RAsac of AV ( P =0.515). The last follow-up RAsac of distal EV was significantly lower than the preoperative RAsac of distal EV ( P =0.001). The Pearson correlation analysis showed that the last follow-up RAsac of distal EV was correlated with the Cobb angle of the main curve ( r =0.459, P =0.004), loss of correction ( r =0.541, P =0.001), and lowest instrumented vertebra tilt angle ( r =0.504, P =0.001). The rotation regression phenomenon in AV and rotation maintenance in distal EV were observed after DVR over an average 10-year follow-up. These findings suggest that the DVR in the surgical treatment of AIS has a positive long-term effect on the stabilization of distal EV from the point of view of axial rotation. 4.

Assessment of reliability and validity of a handheld surface spine scanner for measuring trunk rotation in adolescent idiopathic scoliosis

PurposeTo assess the reliability and validity of a handheld scanner (SpineScan3D) for trunk rotation measurement in adolescent idiopathic scoliosis (AIS) subjects, as compared with Scoliometer.MethodsThis was a cross-sectional study with AIS subjects recruited. Biplanar spine radiographs were performed using an EOS imaging system with coronal Cobb angle (CCA) determined. The angle of trunk rotation (ATR) was measured using Scoliometer. SpineScan3D was employed to assess the axial rotation of subjects’ back at forward bending, recorded as surface tilt angle (STA). Intra- and inter-examiner repeats were conducted to evaluate the reliability of SpineScan3D.Results97 AIS patients were recruited. Intra- and inter-examiner reliability of STA measures were good to excellent in major thoracic and lumbar curves (p < 0.001). A strong correlation was found between STA and ATR measures in both curve types (p < 0.001) with a standard error of the ATR estimate of between 1 and 2 degrees from linear regression models (R squared: 0.8–0.9, p < 0.001). A similar correlation with CCA was found for STA and ATR measures (r: 0.5–0.6, p < 0.002), which also demonstrated a similar sensitivity (72%-74%) and specificity (62%-77%) for diagnosing moderate to severe curves.ConclusionSpineScan3D is a handheld surface scanner with a potential of wide applications in subjects with AIS. The current study indicated that SpineScan3D is reliable and valid for measuring trunk rotation in AIS subjects, comparable to Scoliometer. Further studies are planned to investigate its measurements in coronal and sagittal planes and the potential of this device as a screening and monitoring tool.Trial registration number (date of registration)HKUCTR-2288 (06 Dec 2017).Level of evidenceLevel III.

Where should Scoliometer and EOS Imaging be Applied when Evaluating Spinal Rotation in Adolescent Idiopathic Scoliosis -A Preliminary Study with Reference to CT Images.

Retrospective study. Our purpose was to evaluate spinal rotation measurement by scoliometer or EOS Imagings with reference to that by CT images, and to clarify their applicability in clinical practice. Patients with adolescent idiopathic scoliosis (AIS) who were indicated for surgery were enrolled and the informed consents were obtained. The angle of trunk rotation (ATR) was measured by the scoliometer. Apical vertebral rotation (AVR) was measured with EOS Imaging and CT images. Paired T tests were used to compare the measurements between ATR or AVR-EOS and AVR-CT. Pearson correlation analysis was performed to explore the relationship between ATR or AVR-EOS and AVR-CT. Then subgroup analysis was performed. Forty-seven consecutive AIS patients with 62 curves were identified. In the whole group, the ATR, as well as AVR-EOS, was significantly smaller than the AVR-CT. Both ATR and AVR-EOS correlated with AVR-CT, although AVR-EOS correlated better. In thoracic group, there was no significant difference between ATR and AVR-CT (P = .236). A significant correlation was found between ATR and AVR-CT(r = .574, P < .001). In TL/L group, no significant difference was noted between AVR-EOS and AVR-CT (P = .414), and a significant correlation was found between AVR-EOS and AVR-CT(r = .824, P < .001). ATR by scoliometer is numerically similar to AVR by CT and may evaluate the spinal rotation more appropriately in thoracic spine. AVR by EOS is numerically similar to AVR by CT and may be more applicable in TL/L spine. Appropriate methods could be selected according to the location of the curve.

The Correlation Between Cobb’s Angle and Pedicle Rotation in Adolescent Idiopathic Scoliosis After Surgical Treatment

Background: Adolescent Idiopathic Scoliosis (AIS) is a 3-dimensional deformity that involves not only curve in the coronal and sagittal planes but also rotation of vertebrae based on pedicle rotation. The Cobb’s angle is the gold standard for measuring the lateral curve that could show severity of the spine deformity. The Cobb’s method only evaluate the lateral curve,and the method to determine the pedicle rotation can be used the Nash and Moe’s method.The higher pedicle rotation grade had higher Cobb’s angle. Surgical treatment for scoliosis is indicated for the curve exceeding 40o. Posterior spinal fusion is the most commonly used technique in scoliosis surgery.Objective: To identify the correlation between the Cobb’s Angle and pedicle rotation in AIS after surgical treatment.Methods: The research design used in this study was Cross Sectional. The sample size of this study were 22 subjects using purposive sampling, the independent variable of this study was Cobb’s angle while the dependent variable was pedicle rotation. Spearman’s rank correlation was used to analyze the correlation between variable.Results: The spearman’s rank correlation revealed a significant correlation between the Cobb’s Angle and pedicle rotation in AIS after surgical treatment with the p 0,005 and r 0,462.Conclusion: This study demonstrates there is a significant correlation between Cobb’s angle and pedicle rotation in AIS after surgical treatment with medium strength.

Maximal Axial Vertebral Rotation in Adolescent Idiopathic Scoliosis: Is the Apical Vertebra the Most Rotated?

Study Design:Retrospective cross-sectional study.Objectives:It is generally believed that the apical vertebra has the largest axial rotation in adolescent idiopathic scoliosis. We investigated the relationship between apical axial vertebral rotation (apicalAVR) and maximal axial vertebral rotation (maxAVR) in both major and minor curves using biplanar stereo-imaging.Methods:EOS 2D/3D biplanar radiograph images were collected from 332 patients with adolescent idiopathic scoliosis (Cobb angle range 10°-122°, mean age 14.7 years). Based on the X-ray images, with the help of 3D full spine reconstructions Cobb angle, curvature level, apicalAVR and maxAVR were determined. These parameters were also determined for minor curves in Lenke 2, 3, 4, 6 type patients. Maximal thoracic rotation and maximal thoracolumbar/lumbar rotation were calculated. Statistical analysis was performed with descriptive statistics, Shapiro-Wilk test, and Wilcoxon signed-rank test.Results:The apical vertebrae were the most rotated vertebra in only 40.4% of the major curves, and 31.7% in minor curves. MaxAVR significantly exceeded apicalAVR values in the major curves (P < .001) as well as in minor curves (P < .001). The 2 parameters differed significantly in each severity group and Lenke type.Conclusions:The apical vertebrae were not the most rotated vertebra in more than half of cases investigated indicating that apicalAVR and maxAVR should be considered as 2 distinct parameters, of which maxAVR fully describes the axial dimension of scoliosis. Furthermore, the substitution of maxAVR for the apicalAVR should be especially avoided in double and triple curves, as the apical vertebra was even less commonly the most rotated in minor curves.

Accuracy and Precision of Seven Radiography-Based Measurement Methods of Vertebral Axial Rotation in Adolescent Idiopathic Scoliosis

Study DesignAssessment of vertebral axial rotation measurement methods. ObjectivesTo assess the accuracy and precision of seven radiography-based vertebral axial rotation measurement methods for typical scoliotic deformity before and after posterior instrumentation. Summary of Background DataVertebral axial rotation is an important component to evaluate transverse plane scoliotic deformities. Several measurement methods were developed based on coronal plane radiographs or computerized 3D reconstruction. Their ability to accurately and precisely measure axial rotation, either pre- or postoperatively, is not well known. MethodsTwo synthetic vertebrae, with and without instrumentation, were fixed in a jig allowing 3D rotation manipulations. Fifty-three configurations of 3D rotations were radiographed. Two observers evaluated seven measurement methods: one visual estimation, two ruler-based (Nash-Moe and Perdriolle), one analytical (Stokes), and three 3D-reconstruction techniques (based on pedicles, based on eight vertebra landmarks, and a surface-based reconstruction software SterEOS). Measurements were repeated one week later. ResultsIntraobserver precision ranged from 2.0° (Perdriolle/SterEOS) to 3.6° (visual estimation) for the noninstrumented vertebra, and from 2.2° (SterEOS) to 9.7° (Nash-Moe) for the instrumented vertebra. Interobserver precision ranged from 1.2° (SterEOS) to 9.3° (Nash-Moe) for the noninstrumented vertebra, and from 1.7° (SterEOS) to 6.2° (Visual Estimation) for the instrumented vertebra. Accuracy of the methods ranged from 2.1° with SterEOS to 9.1° with Nash-Moe ruler. The measurement error was significantly associated with the level of axial rotation for Nash-Moe and 3D reconstruction techniques with low to moderate correlation. ConclusionsThe majority of radiography-based methods measured vertebral axial rotation with an average error of 2° to 5°. The Nash-Moe method should be avoided, considering its inaccuracy greater than 9°. The instrumentation did not compromise the precision or the accuracy of measurement. The measurement accuracy of 3D reconstruction methods was impaired by the severity of the axial rotation. Level of EvidenceN/A.

Three-dimensional EOS Analysis of Apical Vertebral Rotation in Adolescent Idiopathic Scoliosis.

Apical vertebral rotation (AVR) is increasingly recognized as one of the important radiographic parameters in adolescent idiopathic scoliosis (AIS). EOS enables us to precisely measure AVR by 3-dimensional reconstruction. The objective of the present study was to describe the postoperative correction and the long-term follow-up of AVR in posterior spinal fusion with direct vertebral rotation and elucidate the factors that affected the correction. We retrospectively reviewed 153 consecutive posterior spinal fusion surgeries for AIS performed between 2009 and 2012. Among them, 55 patients who fulfilled the study inclusion criteria with complete preoperative, immediate postoperative, and last follow-up (>1 y) EOS images were included in the present study. EOS 3-dimentional reconstructions were undertaken for each patient. Postoperative AVR correction and the loss of correction were calculated. Preoperative AVR of the major curve averaged 19 degrees (SD=7 degrees), and AVR on immediate postoperative images averaged 9 degrees (SD=6 degrees, P<0.001). AVR at final follow-up averaged 11 degrees (SD=6 degrees, P=0.06). Postoperative correction was larger in all-screw construct than in hybrid construct (55% vs. 36%, P=0.03). The present study is the first study to measure AVR in a large population of AIS patients using EOS 3-dimensional reconstruction. We report the correction magnitude was significantly affected by the construct. Level IV-therapeutic study (case series).

A Novel Method for Estimating Three-Dimensional Apical Vertebral Rotation Using Two-Dimensional Coronal Cobb Angle and Thoracic Kyphosis

Study DesignRetrospective cohort analysis. ObjectivesTo use a large cohort of three-dimensional (3D) spinal reconstructions to create a simple mathematical formula capable of estimating 3D apical vertebral rotation (AVR) based on the correlation with routinely obtained two-dimensional (2D) measurements of scoliosis. Summary of Background DataQuantification of vertebral rotation in AIS using 2-dimensional (2D) imaging is inherently challenging as the axial plane cannot be directly visualized. MethodsA database of 279 3D spinal reconstructions was queried for patients with thoracic major adolescent idiopathic scoliosis (AIS). 2D thoracic Cobb angle, T5–T12 thoracic kyphosis, pelvic incidence, sacral slope, and pelvic tilt were recorded. 3D AVR was calculated for each patient from 3D reconstructions. Patients were divided into development (n = 186) and validation (n = 93) cohorts. Within the development cohort, univariate analysis was performed between 2D measurements and 3D AVR with significance set at p < .05 for inclusion in multivariate analysis. In multivariate analysis, significance was set at p < .01 for inclusion in the final model. Model performance was tested in development and validation cohorts. ResultsOnly 2D thoracic Cobb and T5–T12 thoracic kyphosis had significance in univariate (p < .05) and multivariate analyses (p < .01), meriting inclusion in the final model. 3D AVR (°) = 0.26*(T5–T12 kyphosis) + 0.34*(coronal Cobb) − 5.38. In the development cohort, the model performed well (R = 0.739, r2 = 0.54). In testing with the validation cohort, the model proved generalizability (R = 0.703) and had a mean absolute error <5°. ConclusionsThis model is capable of estimating 3D AVR given 2D thoracic Cobb and T5–T12 kyphosis. The accuracy of this method is comparable to previously reported methods of 2D axial rotation measurement. However, this model provides 3D axial rotation and requires no physical instruments, non-standard measurements, or software programs. Such a model is valuable for both routine evaluation of AIS and operative preparation. Level of EvidenceLevel II, diagnostic.

Commentary on development and assessment of a digital X-ray software tool to determine vertebral rotation in adolescent idiopathic scoliosis

Eijgenraam SM, Boselie TF, Sieben JM, Bastiaenen CH, Willems PC, Arts JJ, Lataster A. Spine J 2015;September 26. pii: S1529-9430(15)01449-7.

Development and assessment of a digital X-ray software tool to determine vertebral rotation in adolescent idiopathic scoliosis

Background ContextThe amount of vertebral rotation in the axial plane is of key importance in the prognosis and treatment of adolescent idiopathic scoliosis (AIS). Current methods to determine vertebral rotation are either designed for use in analogue plain radiographs and not useful in digital images, or lack measurement precision and are therefore less suitable for the follow-up of rotation in AIS patients. PurposeThis study aimed to develop a digital X-ray software tool with high measurement precision to determine vertebral rotation in AIS, and to assess its (concurrent) validity and reliability. Study Design/settingIn this study a combination of basic science and reliability methodology applied in both laboratory and clinical settings was used. MethodsSoftware was developed using the algorithm of the Perdriolle torsion meter for analogue AP plain radiographs of the spine. Software was then assessed for (1) concurrent validity and (2) intra- and interobserver reliability. Plain radiographs of both human cadaver vertebrae and outpatient AIS patients were used. Concurrent validity was measured by two independent observers, both experienced in the assessment of plain radiographs. Reliability-measurements were performed by three independent spine surgeons. ResultsPearson correlation of the software compared with the analogue Perdriolle torsion meter for mid-thoracic vertebrae was 0.98, for low-thoracic vertebrae 0.97 and for lumbar vertebrae 0.97. Measurement exactness of the software was within 5° in 62% of cases and within 10° in 97% of cases. Intraclass correlation coefficient (ICC) for inter-observer reliability was 0.92 (0.91–0.95), ICC for intra-observer reliability was 0.96 (0.94–0.97). ConclusionsWe developed a digital X-ray software tool to determine vertebral rotation in AIS with a substantial concurrent validity and reliability, which may be useful for the follow-up of vertebral rotation in AIS patients.

Characteristics of the pelvic axial rotation in adolescent idiopathic scoliosis: a comparison between major thoracic curve and major thoracolumbar/lumbar curve

Background contextAs the biomechanical foundation of the spine, the pelvis was found to display rotation in the transverse plane in adolescent idiopathic scoliosis (AIS). However, the possible factors influencing the pelvic axial rotation (PAR) and its mechanism in patients with AIS remain unclear. PurposeTo characterize the PAR in AIS patients with right major thoracic (MT) or major left thoracolumbar/lumbar (TL/L) curve and to explore the associated influencing factors and probable mechanism of compensation by analyzing the association between PAR and other spinal radiographic parameters. Study designRetrospective study. Patient sampleAll patients with the primary diagnosis of AIS from January 2008 to November 2009 were retrieved from our scoliosis database. Outcome measuresAge, Cobb angle, and apex rotation of the main curve and the compensatory curve, curve flexibility, and PAR. MethodsOne-hundred thirty-two patients with right MT (14.7±1.8 years, 48±6.9°) and 83 patients with left major TL/L (14.7±1.5 years, 46±6.6°) were retrospectively reviewed. On standing full-spine posteroanterior radiographs, the PAR was quantified by the left/right hemi-pelvis width ratio (L/R ratio); then the subjects in both MT and major TL/L groups were divided into two subgroups: L/R ratio ≤1 (pelvis rotated to the right, R-PAR group); and L/R ratio >1 (pelvis rotated to the left, L-PAR group). Comparisons of all variables were performed between the L- and R-PAR subgroups; correlation and regression analysis were carried out to identify the influencing factors of PAR. ResultsThe majority of the MT and major TL/L patients (75.8% vs. 60.2%) displayed right pelvic rotation, which was in the same direction as the thoracic curve. The incidence of R-PAR was greater in the MT patients than the major TL/L ones (p=.016). Lumbar flexibility in MT patients with R-PAR was greater than in MT patients with L-PAR (0.96±0.27 vs. 0.81±0.33, p=.038), which was contrary to the findings in the major TL/L patients (L-PAR>R-PAR, 0.79±0.15 vs. 0.70±0.22, p=.024). In the MT patients with R-PAR, the L/R ratio showed significant positive correlations with the lumbar Cobb angle (r=0.424) as well as with the apex rotation (r=0.488), which was further identified as an influencing factor (R=0.418) of the PAR. Significant positive correlations between L/R ratio and thoracic apex rotation (r=0.361) also were detected. ConclusionThe majority of AIS patients with right MT or left major TL/L curves were found to have PAR to the right, in the same direction as the thoracic curve. The lumbar flexibility and apex rotation significantly influenced the PAR direction and magnitude. Moreover, the pelvis might be involved in compensation for the MT deformity through its connection with the lumbar spine.

Answer to the Letter to the Editor of J. Padulo concerning: “Vertebral rotation in adolescent idiopathic scoliosis calculated by radiograph and back surface analysis-based methods: correlation between the Raimondi method and rasterstereography” by Mangone M, Raimondi P, Paoloni M, Pellanera S, Di Michele A, Di Renzo S, Vanadia M, Dimaggio M, Murgia M, Santilli V (2013) Eur Spine J 22:367–371

Answer to the Letter to the Editor of J. Padulo concerning: “Vertebral rotation in adolescent idiopathic scoliosis calculated by radiograph and back surface analysis-based methods: correlation between the Raimondi method and rasterstereography” by Mangone M, Raimondi P, Paoloni M, Pellanera S, Di Michele A, Di Renzo S, Vanadia M, Dimaggio M, Murgia M, Santilli V (2013) Eur Spine J 22:367–371

Vertebral rotation in adolescent idiopathic scoliosis calculated by radiograph and back surface analysis-based methods: correlation between the Raimondi method and rasterstereography

The aim of the present research is to evaluate the relationship between an X-ray-based method (i.e. the Raimondi method) and rasterstereography in the evaluation of vertebral rotation (VR) in a sample of adolescent idiopathic scoliosis (AIS) patients. A total of 25 patients (9 males; mean age 14 ± 3 years; mean height 160.7 ± 11.9 cm; mean weight 52.4 ± 10.7 kg) were considered for the present analysis. The mean Cobb angle was 30° ± 9°. The evaluation of VR on radiographs was made using the Raimondi method regolo (Marrapese Editore--Demi S.r.1., Rome). Rasterstereography was performed by means of Formetric 4D(®) (Diers International GmbH, Schlangenbad, Germany). Correlations between rasterstereographic and radiographic measurement of VR were calculated, both for the whole sample and for thoracic and lumbar spinal segments considered separately, as well as for subgroups of patients with a Cobb angle <30° and ≥ 30° using Spearman's correlation coefficient by rank (r (s)). When applied to the entire spine, measurement of VR by means of the two methods highlighted a significant correlation in the whole group (r = 0.52; p < 0.0001), as well as in the <30° Cobb (r = 0.47; p = 0.0001) and ≥ 30° Cobb (r = 0.42; p < 0.0001) subgroups. A significant correlation was found also when lumbar and thoracic VR were considered as separated groups (r = 0.30, p = 0.024 and r = 0.47, p = 0.002, respectively). Rasterstereographic evaluation of VR shows a good correlation with the Raimondi method, thereby confirming the possibility to use this non-invasive method for deformity assessment in AIS patients.

Impact of Direct Vertebral Body Derotation on Rib Prominence

Multicenter retrospective review of prospectively collected data. To determine the extent of rib deformity correction that can be expected with direct vertebral body derotation (DVBD) and investigate factors that may correlate with improved rib deformity correction. DVBD is a powerful tool in the surgical correction of axial rotation in adolescent idiopathic scoliosis. The application of DVBD has decreased the use of thoracoplasty for cosmetic rib deformity correction, but the outcomes of DVBD without adjuvant thoracoplasty have not been well defined. A multicenter database was retrospectively queried to identify patients with adolescent idiopathic scoliosis who underwent posterior spinal fusion with at least 2 years of follow-up and Lenke type 1 to 3 curves. All patients had undergone DVBD maneuvers during their surgery, and patients having undergone concurrent thoracoplasty were excluded from the study. The absolute change and percentage change from preoperative inclinometer readings were correlated with preoperative clinical and radiographic data. A total of 148 patients fulfilled the inclusion criteria. The mean age was 14.7 ± 2.1 years with a mean primary thoracic curve of 55.3° ± 9.3°. The mean preoperative inclinometer reading was 14.8° ± 4.5°, which reduced to 7.5° ± 4.0° postoperatively. Patients had a mean improvement of 54% ± 29% in rib prominence using DVBD. We attempted to correlate 23 of the most commonly used preoperative clinical, radiographic, and operative measures with postoperative inclinometer improvement. Interestingly, none correlated with rib deformity correction, including preoperative rib deformity (P = 0.16), thoracic curve flexibility (P = 0.71), presence of osteotomies (P = 0.60), and thoracic curve magnitude (P = 0.78). Utilizing DVBD, the surgeon can expect approximately 50% reduction in the rib deformity as assessed by inclinometer. This is irrespective of preoperative inclinometer measures, thoracic curve flexibility, and vertebral body rotation on standing and bending radiographs.

Measurement of vertebral rotation in adolescent idiopathic scoliosis with low-dose CT in prone position - method description and reliability analysis.

BackgroundTo our knowledge there is no report in the literature on measurements of vertebral rotation with low-dose computed tomography (CT) in prone position.AimsTo describe and test the reliability of this new method, compare it with other methods in use and evaluate the influence of body position on the degree of vertebral rotation measured by different radiological methods.Study designRetrospective study.Methods25 consecutive patients with adolescent idiopathic scoliosis scheduled for surgery (17 girls, 8 boys) aged 15 ± 2 years (mean ± SD) were included in the analysis of this study. The degree of the vertebral rotation was in all patients measured according to the method of Perdriolle on standing plain radiographs and on supine CT scanogram, and according to the method of Aaro and Dahlborn on axial CT images in prone position and on magnetic resonance imaging (MRI) in supine position. The measurements were done by one neuroradiologist at two different occasions. Bland and Altman statistical approach was used in the reliability assessment.ResultsThe reliability of measuring vertebral rotation by axial CT images in prone position was almost perfect with an intraclass correlation coefficient of 0.95, a random error of the intraobserver differences of 2.3°, a repeatability coefficient of 3.2° and a coefficient of variation of 18.4%. Corresponding values for measurements on CT scanogram were 0.83, 5.1°, 7.2°, and 32.8%, respectively, indicating lower reliability of the latter modality and method. The degree of vertebral rotation measured on standing plain radiographs, prone CT scanogram, axial images on CT in prone position and on MRI in supine position were 25.7 ± 9.8°, 21.9 ± 8.3°, 17.4 ± 7.1°, and 16.1 ± 6.5°, respectively. The vertebral rotation measured on axial CT images in prone position was in average 7.5% larger than that measured on axial MRI in supine position.ConclusionsThis study has shown that measurements of vertebral rotation in prone position were more reliable on axial CT images than on CT scanogram. The measurement of vertebral rotation on CT (corrected to the pelvic tilt) in prone position imposes lower impact of the recumbent position on the vertebral rotation than did MRI in supine position. However, the magnitude of differences is of doubtful clinical significance.

Comparison of Vertebral Rotation Corrected by Different Techniques and Anchors in Surgical Treatment of Adolescent Thoracic Idiopathic Scoliosis

Evaluation of radiographs and computed tomography in patients undergoing different surgical interventions for adolescent idiopathic scoliosis (AIS). To compare the correction of vertebral rotation by different surgical techniques and/or anchors in the treatment of AIS. The technique and the technology used in the surgical treatment of AIS continue to evolve; there is little information about the comparison of the vertebral rotation correction of thoracic scoliosis by different surgical techniques and/or anchors. A retrospective study was performed on 106 consecutive patients with AIS, who underwent selective thoracic fusion with different surgical techniques and/or anchors, including hooks, wires, and pedicle screws on the periapical concave side from a posterior approach and an anterior approach using screws. The selection criteria were as follows: younger than 20 years of age, thoracic scoliosis (Lenke type 1, 2, and 3), selected thoracic fusion, and a minimum 2-year follow-up period, whereas thoracic hyperkyphosis was excluded. The patients were classified into group A (anterior approach, n=27), group H (hooks, n=39), group S (screws, n=25), and group W (wires, n=15). The Cobb angle and apical vertebral rotation were evaluated by plain radiography and computed tomography, respectively, before and after surgery and after 2 years of follow-up. All 4 groups were matched for age, sex, preoperative major curve, and curve flexibility. In all groups, the coronal Cobb angle was significantly improved after surgery, without any significant differences between the 4 groups. The Rotation Angle midline values in group A, group H, and group S were significantly improved after 2 years of follow-up (P<0.01), but not for group W. Rotation Angle sagittal was significantly improved after 2 years only in group A. Classification of each group into 2 subgroups according to the flexibility index (>0.5 and <0.5) provided Rotation Angle sagittal values that demonstrated significant improvement postoperatively (P<0.01) for group A and group S subgroups with a flexibility index >0.5. Compared with the use of hooks and the wires, vertebral rotation in AIS is effectively corrected by either the anterior approach or posterior pedicle screw fixation, especially in patients with more flexible scoliosis (a flexibility index >0.5).