Time-dependent response of scoliotic curvature to orthotic intervention: when should a radiograph be obtained after putting on or taking off a spinal orthosis?

A feasibility study of application of purpose-design frame and 3-D clinical ultrasound in assessment and design of spinal orthoses for adolescent idiopathic scoliosis

BACKGROUND

The immediate in-orthosis correction of adolescent idiopathic scoliosis (AIS) is a useful prognostic parameter for the long-term orthotic treatment outcome. The 3-D clinical ultrasound technique is considered a noninvasive alternative to assess scoliotic deformities that could be applied in the orthotic treatment of AIS.

OBJECTIVE

This study aimed to investigate the feasibility of a purpose-design assessment frame in estimating biomechanical effects of the controlling pads of a spinal orthosis under the guidance of the ultrasound system.

METHODS

Twenty-six subjects with AIS were recruited and arranged to position inside the assessment frame, and controlling pads were applied strategically while the scoliotic deformities were assessed by clinical ultrasound to obtain at least 30% curvature correction, and the body shape was then captured using a computer-aided design and computer-aided manufacture system, and spinal orthoses were subsequently fabricated. The preorthosis and immediate in-orthosis coronal and sagittal X-rays were used for comparison.

RESULTS

X-ray assessments showed that the mean coronal Cobb angle and lumbar lordosis of the subjects from the preorthosis to immediate in-orthosis visits decreased significantly ( p < 0.05) from 29.6° to 16.6°, and from 47.2° to 35.3°, respectively.

CONCLUSIONS

This feasibility study showed that the proposed method would have a good potential to improve orthotic treatment outcome in a documented approach that should be considered for implementation into routine clinical practice aiming to reduce the chance of deformity deterioration leading to surgical intervention. However, a controlled group study is required to compare the results.

Alternate In-Brace and Out-of-Brace Radiographs Are Recommended to Assess Brace Fitting and Curve Progression With Adolescent Idiopathic Scoliosis Follow-Up

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine the prevalence of missed curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment with only in-brace follow-up radiographs, and to provide recommendations on when in-brace and out-of-brace should be obtained during follow-up.

METHODS

133 patients who had documented clinically significant curve progression during brace treatment or only when an out-of-brace radiograph were studied. Of these, 95 patients (71.4%) had curve progression noted on in-brace radiographs while 38 patients (28.6%) showed curve progression only after brace removal. We analyzed differences in age, sex, curve types, Risser stage, months after menarche, standing out-of-brace Cobb angle, correction rate, and flexibility rate between the groups. Multivariate logistic regression was performed to determine factors contributing to curve progression missed during brace treatment.

RESULTS

There were no differences in initial Cobb angle between out-of-brace and in-brace deterioration groups. However, the correction rate was higher (32.7% vs 25.0%; P = .004) in the in-brace deterioration group as compared to the out-of-brace deterioration group. A lower correction rate was more likely to result in out-of-brace deterioration (OR 0.970; P = .019). For thoracic curves, higher flexibility in the curves was more likely to result in out-of-brace deterioration (OR 1.055; P = .045). For double/triple curves, patients with in-brace deterioration had higher correction rate (OR 0.944; P = .034).

CONCLUSIONS

Patients may develop curve progression despite good correction on in-brace radiographs. Those with higher flexibility and suboptimal brace fitting are at-risk. In-brace and out-of-brace radiographs should be taken alternately for brace treatment follow-up.

Predictive Factors on Initial in-brace Correction in Idiopathic Scoliosis: A Systematic Review

STUDY DESIGN

Systematic literature review.

OBJECTIVE

The aim of this study was to systematically review the literature and provide an overview of reported predictive factors on initial in-brace correction in patients with idiopathic scoliosis (IS).

SUMMARY OF BACKGROUND DATA

Brace therapy is the best proven non-surgical treatment for IS. There is strong evidence that lack of initial in-brace correction is associated with brace treatment failure. To improve initial in-brace corrections and subsequently long-term brace treatment success, knowledge about factors influencing initial in-brace correction is a prerequisite.

METHODS

A systematic literature search was performed in Pubmed, Embase, Web-of-Science, Scopus, Cinahl, and Cochrane in November 2020. Studies which reported factors influencing initial in-brace correction in IS patients treated with brace therapy were considered eligible for inclusion.

RESULTS

Of the 4562 potentially eligible articles identified, 28 studies fulfilled the inclusion criteria and were included in this systematic review. Nine studies (32%) were classified as high quality studies and the remaining 19 studies (68%) as low quality. Thirty-four different reported factors were collected from the included studies. Strong evidence was found for increased curve flexibility as favorable predictive factor for initial in-brace correction. Moderate evidence was found for thoracolumbar or lumbar curve pattern as favourable predictive factor, and double major curve pattern as unfavourable predictive factor for initial in-brace correction. Also moderate evidence was found that there is no significant difference on initial in-brace correction between computer-aided design and manufacturing systems (CAD/CAM) braces with or without finite element models (FEM) simulation, and braces fabricated using the conventional plaster-cast.

CONCLUSION

The results of this systematic review indicate that increased curve flexibility is strongly associated with increased initial in-brace correction.Level of Evidence: 1.

A Randomized Controlled Trial to Evaluate the Clinical Effectiveness of 3D-Printed Orthosis in the Management of Adolescent Idiopathic Scoliosis

STUDY DESIGN

Prospective randomized controlled trial.

OBJECTIVE

To compare clinical effectiveness and quality of life (QoL) of the 3D-printed orthosis (3O) and conventional orthosis (CO) for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Using 3D printing technology to design and fabricate orthoses to manage AIS aiming to improve in-orthosis correction and patients' compliance that are considered essential factors of effective treatment. Clinical evaluation was conducted to study the effectiveness of this innovative method.

METHODS

Thirty females with AIS who met the criteria (age 10-14, Cobb 20-40°, Risser sign 0-2, ≤12 months after menarche) were recruited. Subjects were randomly allocated to the 3O group (n = 15, age 12.4, Cobb 31.8°) and CO group (n = 15, age 12.0, Cobb 29.3°). All patients were prescribed for full-time wearing (23 hours/d) and follow-up every 4 to 6 months until bone maturity. Compliance was monitored by thermosensors, while QoL was assessed using three validated questionnaires.

RESULTS

Comparable immediate in-orthosis correction was observed between 3O (-11.6°, P < 0.001) and CO groups (-12.9°, P < 0.001). In the QoL study via SRS-22r, the 3O group got worse results after 3 months in aspects of function, self-image, and mental health (-0.5, -0.6, -0.7, P < 0.05) while the CO group had worse results in aspects of self-image and mental health (-0.3, -0.3, P < 0.05). No significant difference was found in QoL assessments between groups. After 2 years of follow-up, 22 patients were analyzed with 4 dropouts in each group. Comparable angle reduction was observed in both groups (3O: -2.2°, P = 0.364; CO: -3.5°, P = 0.193). There was one subject (9.1%) in the 3O group while two subjects (18.2%) in the CO group had curve progression >5°. Daily wearing hours were 1.9 hours longer in the 3O group than the CO group (17.1 vs. 15.2 hours, P = 0.934).

CONCLUSION

The 3O group could provide comparable clinical effects as compared with the CO group while patients with 3O showed similar compliance and QoL compared to those with CO.Level of Evidence: 1.

Does curve pattern impact on the effects of physiotherapeutic scoliosis specific exercises on Cobb angles of participants with adolescent idiopathic scoliosis: A prospective clinical trial with two years follow-up

Background

Current clinical evidence suggests that a well-planned physiotherapeutic scoliosis specific exercise (PSSE) program is effective for scoliosis regression.

Objectives

We investigated the effect of curve patterns on Cobb angles with PSSE.

Methods

This was a non-randomized prospective clinical trial that recruited participants with adolescent idiopathic scoliosis between January and June 2017. Participants were grouped by curve pattern into major thoracic and major lumbar groups. An outpatient-based PSSE program was conducted with the following schedule of intensive exercise: ≥ 1 session of supervised PSSE per month and > 30min of home exercise 5 days/week in the first 6 months, after which exercise frequency was reduced to 1 session of supervised PSSE every three months and > 30min of home exercise 5 days/week until 2 years after study initiation. Radiographic Cobb angle progressions were identified at the 1, 1.5 and 2-year follow-ups. A mixed model analysis of variance (ANOVA) was performed to examine the differences in Cobb angles between groups at four testing time points. The two-tailed significance level was set to 0.05.

Results

In total, 40 participants were recruited, including 22 with major thoracic curves (5 males and 17 females; mean age 13.5±1.8 years; Cobb angle 18–45 degrees) and 18 with major lumbar curves (7 males and 11 females; mean age 12.7±1.7 years; Cobb angle 15–48 degrees). Curve regressions, namely the reduction of Cobb angles between 7 to 10 degrees were noted in 9.1% of participants in the major thoracic group; reductions of 6 to 13 degrees were noted in 33.3% of participants in the major lumbar group at the 2-year follow-up. Repeated measurements revealed a significant time effect (F_2.2,79.8 = 4.1, p = 0.02), but no group (F_2.2,79.8 = 2.3, p = 0.1) or time × group (F_1,37 = 0.97, p = 0.3) effects in reducing Cobb angles after 2 years of PSSE. A logistic regression analysis revealed that no correlation was observed between curve pattern and curve regression or stabilization (OR: 0.2, 95% CI: 0.31–1.1, p = 0.068) at the 2-year follow-up.

Conclusion

This was the first study to investigate the long-term effects of PSSE in reducing Cobb angles on the basis of major curve location. No significant differences in correction were observed between major thoracic and major lumbar curves. A regression effect and no curve deterioration were noted in both groups at the 2-year follow-up.

Trial registration

ChiCTR1900028073.

Does Curve Regression Occur During Underarm Bracing in Patients with Adolescent Idiopathic Scoliosis?

BACKGROUND

Successful brace treatment entails good control of scoliosis with avoidance of surgery. However, achieving curve regression may be an even better radiological result than prevention of curve progression for patients with adolescent idiopathic scoliosis. Vertebral remodeling may occur with well-fitted braces. Better in-brace curve correction may influence the likelihood of vertebral remodeling and the chance of curve regression. Only a few reports have evaluated curve regression with brace treatment, and the factors associated with these events are unknown.

QUESTIONS/PURPOSES

(1) What changes in curvature are observed with brace treatment for adolescent idiopathic scoliosis? (2) What factors are associated with curve improvement? (3) What factors are associated with curve deterioration? (4) Is curve regression associated with improvements in patient-reported objective outcome scores?

METHODS

Between September 2008 and December 2013, 666 patients with adolescent idiopathic scoliosis underwent underarm brace treatment and were followed until skeletal maturity at 18 years old. Among these patients, 80 were excluded because of early discontinuation of brace treatment (n = 66) and loss to follow-up (n = 14). Hence, 586 patients were included in this study, with a mean brace-wear duration of 3.8 ± 1.5 years and post-weaning follow-up duration of 2.0 ± 1.1 years. The mean age at baseline was 12.6 ± 1.2 years. Most patients were female (87%, 507 of 586) and up to 53% (267 of 507) of females were post-menarche. Bracing outcomes were based on changes in the Cobb angle measured out of brace. These included curve regression, as indicated by at least a 5° reduction in the Cobb angle, curve progression, as indicated by at least a 5° increase in the Cobb angle, and unchanged, as indicated by a change in the Cobb angle of less than 5°. We studied the pre-brace and supine Cobb angles, curve flexibility (pre-brace Cobb angle - supine Cobb angle / pre-brace Cobb angle x 100%), correction rate (pre-brace Cobb angle - in-brace Cobb angle / pre-brace Cobb angle x 100%), location of apical vertebrae, apical ratio (convex vertebral height/concave vertebral height), change in the major curve Cobb angle, and apical ratio post-bracing. The refined 22-item Scoliosis Research Society questionnaire was used for patient-reported outcomes and is composed of five domains (function, pain, appearance, mental health and satisfaction with treatment). Its minimum clinically important difference, based on a scale from 0 to 5, has been quoted as 0.2 for pain, 0.08 for activity and 0.98 for appearance domains. Mental health has no quoted minimum clinically important difference for the adolescent idiopathic scoliosis population. Satisfaction with treatment is described based on improvement or deterioration in domain scores. Intergroup differences between bracing outcomes were evaluated with the Kruskal Wallis test. Univariate analyses of bracing outcomes were performed with a point-biserial correlation coefficient for continuous variables and Pearson's chi-square test for categorical variables. Multivariate logistic regression models were created for improved and deteriorated outcomes. P values < 0.05 were considered significant.

RESULTS

In all, 17% of patients (98 of 586) had an improved angle and 40% of patients (234 of 586) had curve deterioration. In patients who improved, the mean reduction in the Cobb angle was 9 ± 4°, while in patients who deteriorated, the mean increase in the Cobb angle was 15 ± 9°, and this was maintained at the latest post-brace weaning follow-up. Despite a trend for patients with curve regression to have higher baseline flexibility and correction rate, after controlling for age, Risser staging, radius and ulnar grading, and Sanders staging, we found no clinically important differences with increased correction rate or flexibility. We did find that improvement in the Cobb angle after bracing was associated with reduced apical ratio (odds ratio [OR] 0.84 [95% CI 0.80 to 0.87]; p < 0.001). Curve progression was associated with younger age (OR 0.71 [95% CI 0.55 to 0.91]; p = 0.008), pre-menarche status (OR 2.46 [95% CI 1.31 to 4.62]; p = 0.005), and increased apical ratio (OR 1.24 [95% CI 1.19 to 1.30]; p < 0.001) but no clinically important differences were observed with less flexible curves and reduced correction rate. Improvements in scores of the refined 22-item Scoliosis Research Society domains of function (mean difference on a scale from 0 to 5: 0.2; p = 0.001 versus 0.1; p < 0.001) and pain (mean difference on a scale from 0 to 5: 0.2; p = 0.020 versus 0.0; p = 0.853) were greater in the post-brace improvement group than in the deterioration group and fulfilled the minimum clinically important difference threshold. The appearance domain did not fulfill the minimum clinically important difference. Satisfaction with treatment domain score minimally improved with the curve regression group (mean difference on a scale from 0 to 5: 0.2) but deteriorated in the curve progression group (mean difference on a scale from 0 to 5: -0.4).

CONCLUSIONS

Curve regression occurs after underarm bracing and is associated with superior patient-reported outcome scores. This possible change in Cobb angle should be explained to patients before and during bracing. Whether this may help improve patients' duration of brace-wear should be addressed in future studies. Patients with well-fitting braces may experience curve improvement and possible vertebral remodeling. Those braced at a younger age and with increased vertebral wedging are more likely to have curve progression.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Coronal deformity angular ratio may serve as a valuable parameter to predict in-brace correction in patients with adolescent idiopathic scoliosis

BACKGROUND CONTEXT

In-brace correction (IBC) plays an important role in curve progression of patients with adolescent idiopathic scoliosis (AIS) under brace treatment. We evaluated the coronal deformity angular ratio (C-DAR) as a potential predictor of IBC. Based on our experience, we postulated that a high C-DAR may result in low IBC. This relationship had not been previously studied.

PURPOSE

To evaluate the relationship of C-DAR and IBC in patients with AIS.

STUDY DESIGN/SETTING

A retrospective study.

PATIENT SAMPLE

A total of 119 patients with AIS treated with a Gensingen brace in our scoliosis center from July 2015 to October 2017 were included.

OUTCOME MEASURES

In-brace correction.

METHODS

Data were collected before and upon brace placement. Correlation analyses between study variables and IBC were performed. A linear regression model was established on the basis of C-DAR.

RESULTS

At brace fitting, the average age was 12.62±1.16 (range, 10-15) years and mean major curve Cobb angle was 32.14±4.66° (range, 25-40°). Mean IBC was 59.62%±22.03% (range, 16.2-100%). IBC had significant correlation with C-DAR (r=-0.69; 95% confidence interval, -0.77 to -0.61; p<.001). IBC was not significantly correlated with age, sex, height, weight, BMI, menstrual status, or Risser sign. A simple linear regression model established that in-brace correction=115.4-10.7×C-DAR.

CONCLUSIONS

C-DAR has strong negative correlation with IBC and may estimate the expected IBC. The usage of C-DAR may obviate the need for flexibility radiographs, such as supine or supine lateral bending radiographs.

Predictability of Supine Radiographs for Determining In-Brace Correction for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective radiographic study.

OBJECTIVE

To assess whether flexibility as revealed by the supine radiograph, predicts in-brace curve correction.

SUMMARY OF BACKGROUND DATA

Currently there is no consensus regarding a standard method to assess curve flexibility and immediate brace effectiveness in treating adolescent idiopathic scoliosis (AIS). Brace fabrication methods may be variable but ideally it should achieve maximal curve correction. Curve flexibility governs the degree of curve correction in-brace and hence dynamic radiographs are commonly performed prior to brace fitting.

METHODS

This was a radiographic analysis of AIS patients treated with underarm bracing. Correlation of pre-brace, supine, and immediate in-brace Cobb angles was performed. Relationship with possible contributing factors including age, sex, body height, weight, age at menarche and Risser staging was studied. Major and minor curves were compared independently for correlation but the regression model was constructed based on the major curve only.

RESULTS

From 105 patients with mean age of 12.2 ± 1.2 years at brace fitting, supine Cobb angle measurement has significant correlation with immediate in-brace Cobb angle (r = 0.740). Univariate analyses showed no significant relationship with age, weight, height, date of menarche, Risser stage or pre-brace Cobb angle. Our regression model (in-brace Cobb angle = 0.809 × supine Cobb angle) had good fit of the data.

CONCLUSION

Supine radiograph predictably determines the flexibility of the scoliotic curve to brace treatment. It can be used as a guideline to determine the amount of correction achievable with brace-wear. The effectiveness of the brace is dependent on the inherent flexibility of the curve rather than its size or type.

LEVEL OF EVIDENCE

3.

Mechanical and Clinical Evaluation of a Shape Memory Alloy and Conventional Struts in a Flexible Scoliotic Brace

Smart materials have attracted considerable attention in the medical field. In particular, shape memory alloys (SMAs) are most commonly utilized for their superelasticity (SE) in orthopaedic treatment. In this study, the resin struts of a flexible brace for adolescent idiopathic scoliosis (AIS) are replaced with different conventional materials and an SMA. The corrective mechanism mainly depends on the compressive force applied by the brace at the desired location. Therefore, the mechanical properties of the materials used and the interface pressure are both critical factors that influence the treatment effectiveness. The results indicate that titanium is the most rigid among the five types of materials, whereas the brace with SMA struts presents the best recovery properties and the most stable interface pressure. A radiographic examination of two patients with AIS is then conducted to validate the results, which shows that the SMA struts can provide better correction of thoracic curvature. These findings suggest that SMAs can be applied in orthoses because their SE allows for continuous and controllable corrective forces.

An effective assessment method of spinal flexibility to predict the initial in-orthosis correction on the patients with adolescent idiopathic scoliosis (AIS)

BACKGROUND

Spinal flexibility is an essential parameter for clinical decision making on the patients with adolescent idiopathic scoliosis (AIS). Various methods are proposed to assess spinal flexibility, but which assessment method is more effective to predict the effect of orthotic treatment is unclear.

OBJECTIVE

To investigate an effective assessment method of spinal flexibility to predict the initial in-orthosis correction, among the supine, prone, sitting with lateral bending and prone with lateral bending positions.

METHODS

Thirty-five patients with AIS (mean Cobb angle: 28° ± 7°; mean age: 12 ± 2 years; Risser sign: 0-2) were recruited. Before orthosis fitting, spinal flexibility was assessed by an ultrasound system in 4 positions (apart from standing) including supine, prone, sitting with lateral bending and prone with lateral bending. After orthosis fitting, the initial in-orthosis correction was routinely assessed by whole spine standing radiograph. Comparisons and correlation analyses were performed between the spinal flexibility in the 4 positions and the initial in-orthosis correction.

RESULTS

The mean in-orthosis correction was 41% while the mean curve correction (spinal flexibility) in the 4 studied positions were 40% (supine), 42% (prone), 127% (prone with lateral bending) and 143% (sitting with lateral bending). The correlation coefficients between initial in-orthosis correction and curve correction (spinal flexibility) in the 4 studied positions were r = 0.66 (supine), r = 0.75 (prone), r = 0.03 (prone with lateral bending) and r = 0.04 (sitting with lateral bending).

CONCLUSIONS

The spinal flexibility in the prone position is the closest to and most correlated with the initial in-orthosis correction among the 4 studied positions. Thus, the prone position could be an effective method to predict the initial effect of orthotic treatment on the patients with AIS.

Results of ultrasound-assisted brace casting for adolescent idiopathic scoliosis

Background

Four factors have been reported to affect brace treatment outcome: (1) growth or curve based risk, (2) the in-brace correction, (3) the brace wear quantity, and (4) the brace wear quality. The quality of brace design affects the in-brace correction and comfort which indirectly affects the brace wear quantity and quality. This paper reported the immediate benefits and results on using ultrasound (US) to aid orthotists to design braces for the treatment of scoliosis.

Methods

Thirty-four AIS subjects participated in this study with 17 (2 males, 15 females) in the control group and 17 (2 males, 15 females) in the intervention (US) group. All participants were prescribed full time TLSO, constructed by either of the 2 orthotists in fabrication of spinal braces. For the control group, the Providence brace design system was adopted to design full time braces. For the intervention group, the custom standing Providence brace design system, plus a medical ultrasound system, a custom pressure measurement system and an in-house software were used to assist brace casting.

Results

In the control group, 8 of 17 (47%) subjects needed a total of 11 brace adjustments after initial fabrication requiring a total of 28 in-brace radiographs. Three subjects (18%) required a second adjustment. For the US group, only 1 subject (6%) required adjustment. The total number of in-brace radiographs was 18. The p value of the chi-square for requiring brace adjustment was 0.006 which was a statistically significant difference between the two groups. In the intervention group, the immediate in-brace correction as measured from radiographs was 48 ± 17%, and in the control group the first and second in-brace correction was 33 ± 19% and 40 ± 20%, respectively. The unpaired 2 sided Student’s t test of the in-brace correction was significantly different between the US and the first follow-up of the control group (p = 0.02), but was not significant after the second brace adjustment (p = 0.22).

Conclusions

The use of the 3D ultrasound system provided a radiation-free method to determine the optimum pressure level and location to assist brace design, resulting in decreased radiation exposure during follow-up brace evaluation, increased the in-brace correction, reduced the patients’ visits to both brace adjustment and scoliosis clinics. However, the final outcomes could not be reported yet as some of patients are still under brace treatment.

Trial registration

NCT02996643, retrospectively registered in 16 December 2016

An alternative to a randomised control design for assessing the efficacy and effectiveness of bracing in adolescent idiopathic scoliosis

Randomised controlled trials (RCTs) that assessed the efficacy of bracing for adolescent idiopathic scoliosis have suffered from small sample sizes, low compliance and lack of willingness to participate. The aim of this study was to assess the feasibility of a comprehensive cohort study for evaluating both the efficacy and the effectiveness of bracing in patients with adolescent idiopathic scoliosis. Patients with curves at greater risk of progression were invited to join a randomised controlled trial. Those who declined were given the option to remain in the study and to choose whether they wished to be braced or observed. Of 87 eligible patients (5 boys and 63 girls) identified over one year, 68 (78%) with mean age of 12.5 years (10 to 15) consented to participate, with a mean follow-up of 168 weeks (0 to 290). Of these, 19 (28%) accepted randomisation. Of those who declined randomisation, 18 (37%) chose a brace. Patients who were more satisfied with their image were more likely to choose bracing (Odds Ratio 4.1; 95% confidence interval 1.1 to 15.0; p = 0.035). This comprehensive cohort study design facilitates the assessment of both efficacy and effectiveness of bracing in patients with adolescent idiopathic scoliosis, which is not feasible in a conventional randomised controlled trial.

Reliability and Validity Study of Clinical Ultrasound Imaging on Lateral Curvature of Adolescent Idiopathic Scoliosis

Background

Non-ionizing radiation imaging assessment has been advocated for the patients with adolescent idiopathic scoliosis (AIS). As one of the radiation-free methods, ultrasound imaging has gained growing attention in scoliosis assessment over the past decade. The center of laminae (COL) method has been proposed to measure the spinal curvature in the coronal plane of ultrasound image. However, the reliability and validity of this ultrasound method have not been validated in the clinical setting.

Objectives

To evaluate the reliability and validity of clinical ultrasound imaging on lateral curvature measurements of AIS with their corresponding magnetic resonance imaging (MRI) measurements.

Methods

Thirty curves (ranged 10.2°–68.2°) from sixteen patients with AIS were eligible for this study. The ultrasound scan was performed using a 3-D ultrasound unit within the same morning of MRI examination. Two researchers were involved in data collection of these two examinations. The COL method was used to measure the coronal curvature in ultrasound image, compared with the Cobb method in MRI. The intra- and inter-rater reliability of the COL method was evaluated by intra-class correlation coefficient (ICC). The validity of this method was analyzed by paired Student’s t-test, Bland–Altman statistics and Pearson correlation coefficient. The level of significance was set as 0.05.

Results

The COL method showed high intra- and inter-rater reliabilities (both with ICC (2, K) >0.9, p<0.05) to measure the coronal curvature. Compared with Cobb method, COL method showed no significant difference (p<0.05) when measuring coronal curvature. Furthermore, Bland-Altman method demonstrated an agreement between these two methods, and Pearson’s correlation coefficient (r) was high (r>0.9, p<0.05).

Conclusion

The ultrasound imaging could provide a reliable and valid measurement of spinal curvature in the coronal plane using the COL method. Further research is needed to validate the proposed ultrasound measurement in larger clinical trial and to optimize the ultrasound scanning and measuring procedure.