Radiographic methods to estimate surgical outcomes based on spinal flexibility assessment in patients who have adolescent idiopathic scoliosis: A systematic review

Do Preoperative Supine Radiographs Predict Postoperative Residual Lumbar Curvatures in Adolescent Idiopathic Scoliosis? A Retrospective Cohort Study

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

This study compares supine vs bending flexibility radiographs and evaluates their ability to predict residual postoperative lumbar curvature after selective thoracic fusion for Lenke 1 and 2 curves across different lumbar modifiers (A, B, and C) in adolescent idiopathic scoliosis (AIS).

METHODS

This was a retrospective review of AIS Lenke 1 and 2 patients who underwent posterior fusion. All patients had preoperative flexibility radiographs including side-bending and supine posteroanterior (PA) films, in addition to pre- and post-operative standing PA and lateral radiographs. We used SurgiMap 2.0 software for all radiographic measurements. Pearson correlations and linear regression models were developed in SAS.

RESULTS

A total of 86 patients were included mean age 14.9 years and follow-up 72.3 months. Preoperative supine lumbar Cobb angle and preoperative side-bending Cobb angles had similar, positive correlations with postoperative lumbar Cobb angle, r = .55 (P < .001) and r = .54 (P < .001), respectively. Three regression models were built to predict postoperative lumbar Cobb angles from preoperative information: Model S (R2 = .39) uses preoperative supine lumbar curve; Model B (R2 = .44) uses preoperative side-bending lumbar curve; Model SB (R2 = .49) uses both preoperative supine and side-bending lumbar curves. Model S and B performed just as well as Model SB.

CONCLUSION

Either supine or side-bending radiographs alone may be used to estimate mean residual postoperative lumbar curvature after selective posterior thoracic fusion, but little is to be gained by taking both supine and side-bending radiographs.

Side bending radiographs and lowest instrumented vertebra in adolescent idiopathic scoliosis: A French quality-of-care study

BACKGROUND

Determining which spinal levels to instrument during surgical treatment of Lenke Type 1 adolescent idiopathic scoliosis (AIS) depends on the reducibility of the primary and secondary curve patterns. This reducibility can be evaluated in several ways, with the most popular being radiographs in bending for moderate thoracic and lumbar curvatures. Hypothesis Side-bending radiographs will alter the choice of the lowest instrumented vertebra (LIV) for the surgical treatment of AIS.

METHODS

Thirteen experienced French spine surgeons were invited to perform surgical planning on 23 patients based on stereoradiographs with and without (standing) side-bending views. The surgical planning was repeated a second time to assess the intra- and inter-rater reliability. Variations in the choice of LIV were analyzed for each evaluation.

RESULTS

The intra-rater reliability was moderate to substantial. The inter-rater reliability was low to moderate. The study compared 879 surgical plans. Selective fusion was chosen in 0.3% of the plans. The median LIV was L2. The availability of side bending views changed the plan in 39% of cases. However, 36% of the plans were changed in the control (test-retest) condition. No significant difference was found between the variations with side-bending radiographs and "control" variations (p>0.05).

CONCLUSION

The use of radiographs in bending has no significant effect on the LIV choice in this study. This result is derived from statistically robust analysis made possible by one of the largest datasets available on this topic. Large inter-rater variability was observed and will be explored further in a future study.

LEVEL OF EVIDENCE

II; non-randomized controlled comparative study.

Supine Traction Versus Prone Bending Radiographs for Assessing the Curve Flexibility in Spinal Deformity

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

No consensus exists among surgeons on which radiologic method to prefer for the assessment of curve flexibility in spinal deformity. The objective of this study was to evaluate the difference in curve correction on supine traction radiographs versus prone side bending radiographs.

METHODS

A retrospective analysis of idiopathic scoliosis (IS), degenerative idiopathic scoliosis (DIS) and de novo degenerative lumbar scoliosis (DNDLS) patients was performed on supine traction as well as prone bending films (when available). Age, weight, traction force, diagnosis and Cobb angles of the primary and secondary curves were extracted. Differences in curve correction (percentages) on traction versus prone bending radiographs were analyzed for the primary and secondary curve. Subgroup analyses were performed for the 3 different diagnoses.

RESULTS

In total, 170 patients were eligible for inclusion. 43 were diagnosed with IS, 58 with DIS and 69 with DNDLS. For the primary curve, greater curve correction was obtained with bending in the DNDLS group (P < 0.001). In the DIS group, there was a trend toward more correction on bending (P = 0.054). In de IS group no difference was found. For the secondary curve, bending showed more curve correction in the IS and DIS group (P = 0.002 and P <0.001). No difference was found in the DNDLS group.

CONCLUSION

Compared to traction radiographs, bending radiographs better serve the purpose of curve flexibility assessment of IS, DIS and DNDLS spinal deformity, despite the fact that patients are exposed to more radiation.

Evaluating flexibility and predicting curve correction using fulcrum-bending radiographs in Lenke type 2 adolescent idiopathic scoliosis

BACKGROUND

Fulcrum-bending (FB) correction is considered to provide the best estimation of main thoracic (MT) curve flexibility and postoperative correction in surgical treatment for adolescent idiopathic scoliosis (AIS). However, few studies evaluated the usefulness of FB radiographs for proximal thoracic (PT) curve. We aimed to perform flexibility assessments using both active side-bending (SB) and FB radiographs and evaluate surgical outcomes after posterior spinal fusion (PSF) for Lenke type 2 AIS.

METHODS

This study included 38 consecutive patients with Lenke type 2 AIS who underwent PSF using a pedicle screw construct with a minimum 2-year follow-up. Radiographic parameters, including correction rate, SB and FB flexibility, and FB correction index (FBCI: [correction rate/FB flexibility] × 100), were evaluated preoperatively, immediately after surgery, and at the 2-year follow-up. The clinical outcomes were preoperatively evaluated using the Scoliosis Research Outcomes Instrument-22 and at the follow-up.

RESULTS

All scoliosis curves significantly improved and shoulder balance shifted toward left shoulder elevation (all comparisons, p < 0.0001). There were significant differences between the SB and FB corrections in the PT and MT curves (p < 0.0001). The magnitudes of the discrepancies between the SB and FB corrections in the PT and MT curves were 11.2° ± 5.2° and 11.6° ± 7.2°, respectively. FB correction did not differ from postoperative Cobb angles correction immediately after surgery or at the 2-year follow-up; the mean FBCIs in the PT and MT curves were 98.8% and 105.5%, respectively. The self-image domain SRS-22 scores had significantly increased at the 2-year follow-up (p < 0.0001).

CONCLUSIONS

There were significant differences between the SB and FB corrections, and FB correction tended to approximate the postoperative curve correction (FBCI = 100%) for PT and MT curves in patients with Lenke type 2 AIS. FB flexibility is more reliable than SB flexibility in evaluating actual curve flexibility even for the PT curve.

Hanging radiograph in idiopathic scoliosis patients: significance as a preoperative stress X-ray

BACKGROUND

Before corrective surgery for idiopathic scoliosis, the stress X-rays are indispensable to collect information regarding the reducibility of deformity, deciding fusion levels, and categorizing curve types and so on. The hanging radiograph has not been conducted preoperatively so far as known. The objective of this study was to investigate retrospectively the significance of the hanging radiograph for prediction of the curve correction with surgical procedure by comparing with the side-bending and the traction radiographs.

METHODS

The subjects enrolled in current study were 22 cases of idiopathic scoliosis who performed posterior instrumentation and fusion by ISOLA method between 2008 and 2014. They included 2 males and 20 females, with a mean age of 16 years and 8 months. The type of curves by Lenke classification were type 1 in 20 cases, type 2 in 1 case, and type 3 in 1 case. We investigated the correction rates of main thoracic curves in side-bending, traction, and hanging positions and compared them with that after surgery. In addition, correction indices were also calculated and compared among these stress X-rays.

RESULTS

The correction rate after surgery was 65.9% that was statistically higher than those in side-bending (44.2%), traction (46.6%), and hanging (22.1%) positions. There were statistical correlations between the correction rates after surgery and in side-bending position (R=0.73) and those after surgery and in traction position (R=0.57). However, there was no statistical correlation between the correction rates after surgery and in hanging position (R=-0.01). With regard to the correction indices, that in hanging position (3.67) was statistically higher than those in side-bending (1.51) and traction (1.45) positions.

CONCLUSIONS

The correction rates in side-bending and traction positions seem to be useful to estimate the amount of curve correction before surgery. Whereas, that in hanging position did not have any significance as preoperative evaluation.

Postoperative Correction in Idiopathic Scoliosis: Which Preoperative Imaging Technique Is Most Predictive?

INTRODUCTION

Preoperative radiographic assessment of curve flexibility in patients with idiopathic scoliosis is important to determine Lenke classification, operative levels, and potential postoperative correction. However, no consensus exists regarding the optimal technique. We compared measurements from supine side bending (SB) and intraoperative traction radiographs under general anesthesia (TUGA) with actual postoperative correction followed for 1 year.

METHODS

We identified 235 patients with idiopathic scoliosis who underwent posterior spinal fusion with pedicle screw instrumentation between 2010 and 2018 who had preoperative and postoperative radiographs including standing posterior-anterior (PA) and lateral radiographs, preoperative SB radiographs, and TUGA radiographs. Curves were categorized into proximal thoracic, main thoracic/thoracolumbar (MT), and distal thoracolumbar/lumbar (TL/L) curves. Flexibility was calculated from SB and TUGA radiographs. Correction rates were calculated from 1 month and 1 year radiographs postoperatively. Bending radiographs that correlated significantly with postoperative correction with P<0.10 were eligible for inclusion. Preoperative demographics, etiology, deformity details, and surgical details were included in the multivariate models.

RESULTS

On univariate analysis, TUGA radiographs correlated with postoperative correction at 1 month and 1 year on MT curves (r=0.214, P=0.001; r=0.209, P=0.001) and TL/L curves (r=0.280, P<0.001; r=0.181, P=0.006). Supine SB radiographs did not correlate with postoperative correction on either MT or T/TL curves. On multivariate analysis, major curve TUGA radiographs were independently associated with postoperative MT curve correction at 1 month (beta: 0.158, 95% confidence interval: 0.035-0.280, P=0.012) and 1 year (beta: 0.195, 95% confidence interval: 0.049-0.340, P=0.009). MT curve SB radiographs were not associated with postoperative major curve correction at 1 month (P=0.088).

CONCLUSIONS

TUGA radiographs independently correlated with postoperative main thoracic and distal thoracolumbar/lumbar curve correction at 1 month and 1 year postoperatively. SB radiographs independently correlated only with TL/L curve correction at 1 year postoperatively. However, this correlation was not as strong as TUGA correction (beta of 0.280 vs. beta of 0.092). TUGA radiographs appear superior to SB radiographs at predicting curve correction after surgery.

LEVEL OF EVIDENCE

Level III.

Comparison of slot-scanning standing, supine, and fulcrum radiographs for assessment of curve flexibility in adolescent idiopathic scoliosis: a pilot study

PURPOSE

With the goal of reducing radiation dosing for patients, we sought to compare the results of slot-scanning (EOS) standing flexibility radiographs to supine bending and fulcrum radiographs for surgical planning in adolescent idiopathic scoliosis (AIS). We hypothesized that slot-scanning standing bending radiographs provide similar mean curve flexibility as supine bending and fulcrum radiographs.

METHODS

This is a retrospective review of 224 AIS patients with concomitant upright standing and flexibility images. Curve flexibility, defined the percent change in Cobb angle from standing upright to flexibility images, was used to compare the results of slot-scanning standing, supine and fulcrum radiographs. Statistical analysis utilized ANOVA one-way tests and two-sample t tests to detail differences as indicated.

RESULTS

A total of 256 imaging studies were included, 75 slot-scanning standing, 112 supine, and 69 fulcrum radiographs. Fulcrum images only investigated thoracic curves and were, therefore, excluded from proximal thoracic and lumbar flexibility comparisons. Relevant mean standing curve magnitudes were similar between the groups with some variance in thoracic curves between fulcrum and supine image series (p = 0.003). There was no statistical difference in curve flexibility for proximal thoracic curves (p = 0.389) and lumbar curves (p = 0.798). However, for thoracic curves, slot-scanning standing images result in less measured curve flexibility compared to supine (p = 1.00E-7) and fulcrum images (p = 2.84E-18). Furthermore, supine bending images resulted in less measured curve flexibility in comparison to fulcrum images (p = 2.85E-7).

CONCLUSION

Slot-scanning standing bending films show comparable results in curve flexibility as supine bending films for proximal thoracic and lumbar curves but may show reduced flexibility for thoracic curves when compared to supine or fulcrum bending films. Given lower radiation dosing, slot-scanning films could be substituted for traditional supine films for assessment of proximal thoracic and lumbar curve flexibility.

COMPARISON BETWEEN RADIOGRAPHIC METHODS OF MEASURING FLEXIBILITY IN SCOLIOSIS

ABSTRACT Objective: To determine the preoperative radiographic method for measuring the Cobb angle that is closest to the postoperative result in patients with scoliotic deformity. Methods: Retrospective cohort study of radiographic spinal evaluation (preoperative posteroanterior (PA), bending, traction, traction under anesthesia and immediate postoperative posteroanterior (PO)) of 26 patients treated surgically for scoliotic deformities during the period from January 2017 to September 2019. The final mean Cobb angle and its decrease in relation to the PA value were evaluated in the three curves in patients with idiopathic (IS) and non-idiopathic scoliosis. Results: All the mean curve values were statistically significant, except for bending in non-idiopathic scoliosis (non-IS). The mean traction under anesthesia values were closer to the PO values. Regarding the delta (decrease) of the maneuvers in relation to the PA, no statistical significance was observed in the non-IS group. The traction under anesthesia maneuver had a greater delta in all curves. Conclusions: The traction under anesthesia maneuver in patients with idiopathic scoliosis is the method with the greatest flexibility and which best predicts the postoperative result. Level of evidence III; Diagnostic study.

Reliability of measurements of a reflection coefficient index to indicate spinal bone strength on adolescents with idiopathic scoliosis (AIS): a pilot study

PURPOSE

To investigate the test-retest, intra- and inter-rater reliabilities of an ultrasound (US) reflection coefficient (RC) index measured in a lumbar vertebra to reflect bone strength on children with AIS.

METHODS

Fifty-eight participants (47F; 11M) were scanned by an US imager in standing position. Twenty-four were scanned twice for a test-retest study. The RC index measures the US signal reflected from L5 to indicate bone strength. Five measurements were obtained using three different methods: (i) the maximum RC (MRC) values on the left and right sides, (ii) the average RC (ARC) values on left and right sides, and (iii) the combined average RC (CARC) from both sides. Only rater 1 measured the 24 repeated US scans once. Raters 1 and 2 measured the RC index twice on all 58 images in 1 week apart. The intraclass correlation coefficient ICC [3, 1] for test-retest and ICC [2, 1] for intra- and inter-rater reliabilities as well as the standard error of measurements (SEM) were reported.

RESULTS

The means of scan 1 versus scan 2 were 0.16 ± 0.08 versus 0.16 ± 0.07 for left-MRC, 0.17 ± 0.11 versus 0.18 ± 0.11 for right-MRC, 0.08 ± 0.04 versus 0.09 ± 0.04 for left-ARC, 0.09 ± 0.04 versus 0.09 ± 0.05 for right-ARC and 0.08 ± 0.04 versus 0.09 ± 0.03 for CARC and all ICC[3, 1] ≥ 0.77. Among these 5 approaches, the CARC provided the best intra-rater and inter-rater reliabilities with ICC [2, 1] ≥ 0.84 and SEM ≤ 0.01.

CONCLUSIONS

The RC index could be measured repeatably and reliably. The high RC value may reduce the risk of progression of scoliosis.

Perioperative outcome of severe rigid idiopathic scoliosis: Single-staged posterior spinal fusion utilizing a dual attending surgeon strategy. A report of 41 patients

PURPOSE

Various surgical strategies including combined approach and spinal osteotomies in severe rigid scoliosis had been reported with significant perioperative complication rates. The use of single-staged posterior spinal fusion (PSF) utilizing a dual attending surgeon strategy for severe rigid scoliosis has not been widely reported.

METHODS

This was a retrospective study aimed to evaluate the perioperative outcome of single-staged PSF in severe rigid idiopathic scoliosis patients (Cobb angle ≥90° and ≤30% flexibility). Forty-one patients with severe rigid idiopathic scoliosis who underwent single-staged PSF were included. The perioperative outcome parameters were operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, transfusion rate, patient-controlled anesthesia morphine usage, length of postoperative hospital stay, and perioperative complications. Radiological parameters included preoperative and postoperative Cobb angle, correction rate, side-bending flexibility, and side-bending correction index.

RESULTS

The mean age was 16.9 ± 5.6 years. The mean preoperative Cobb angle was 110.8 ± 12.1° with mean flexibility of 23.1 ± 6.3%. The mean operation duration was 215.5 ± 45.2 min with mean blood loss of 1752.6 ± 830.5 mL. The allogeneic blood transfusion rate was 24.4%. The mean postoperative hospital stay was 76.9 ± 26.7 h. The mean postoperative Cobb angle and correction rate were 54.4 ± 12.8° and 50.9 ± 10.1%, respectively. The readmission rate in this cohort was 2.4%. Four perioperative complications were documented (9.8%), one somatosensory evoke potential signal loss, one superficial infection, one lung collapse, and one superior mesenteric artery syndrome.

CONCLUSIONS

Severe rigid idiopathic scoliosis treated with single-staged PSF utilizing a dual attending surgeon strategy demonstrated an average correction rate of 50.9%, operation duration of 215.5 min, and postoperative hospital stay of 76.9 h with a 9.8% perioperative complication rate.

Segmental Flexibility in Adolescent Idiopathic Scoliosis Assessed Using the Fulcrum-bending Radiography Method

INTRODUCTION

Assessment of segmental flexibility at each disk level of the scoliotic curve in patients with adolescent idiopathic scoliosis (AIS) has rarely been performed, despite its importance for surgical planning of fusion levels. The fulcrum-bending radiography method could be used to assess flexibility at specific spinal segments of the scoliotic curve for preoperative planning. Therefore, our aim was to use the fulcrum-bending method to evaluate the pattern of segmental flexibility in patients with AIS.

MATERIALS AND METHODS

Our retrospective analysis was based on preoperative fulcrum-bending radiographs in 21 patients presenting with main thoracic curve scoliosis. The apex vertebra was defined as the "0" level, with the sequential cranial disk levels defined as "+1 to +5" and the sequential caudal levels as "-1 to -5." The segmental Cobb angle was measured on both, standing and fulcrum-bending radiographs. The segmental flexibility index (FI) was calculated as: [(the segmental Cobb angle in standing position-the segmental Cobb angle in the fulcrum-bending position)/the segmental Cobb angle in standing position]×100. The FI was measured from the upper-most to the lower-most end vertebrae of the main curve.

RESULTS

There was a significant difference in the FI among segments, with the greatest flexibility detected at the level of the -5 disk (median FI, 50%) and least flexibility at the periapical segments (+1 and -1; FI, 50%-66.7%).

CONCLUSIONS

The curve around the apex and upper thoracic segments in thoracic AIS is relatively rigid. Understanding differences in FI between each disk level is important for optimal corrective surgery.

RADIOGRAPHICAL ANALYSIS OF FLEXIBILITY OF IDIOPATIC SCOLIOSIS IN PRONO AND SUPINO

ABSTRACT Objective To determine if there is a statistically significant difference in the flexibility of the curves in the adolescent idiopathic scoliosis (AIS) by using lateral inclination radiographs in supine or prone decubitus. Methods We evaluated 19 patients with AIS, waiting for surgery. Radiographs of the patients were performed in orthostatic anteroposterior incidences and right and left lateral inclinations in prone and supine decubitus. The comparison between prone and supine decubitus was performed through the flexibility rates of the curves measured in each position. Results The mean flexibility rates measured in lateral inclination radiographs with the patient in the supine position were 54.4% ± 38.8% in the proximal thoracic curve, 45.8% ± 15.6% in the main thoracic curve, and 80.5% ± 20.7% in the thoracolumbar / lumbar curve. When the lateral inclination radiographs were performed with the patient in the prone position, we observed mean flexibility rates of 66.4% ± 34.3% in the proximal thoracic curve, 50.1% ± 12.8% in the main thoracic curve, and 80.6% ± 19.0% in the thoracolumbar / lumbar curve. Conclusion This present study did not find a statistically significant difference between the flexibility rates of the curves in the prone and supine positions, suggesting that the two radiographic methods analyzed are similar in the evaluation of the flexibility of the curves in adolescent idiopathic scoliosis. Level of evidence II; Development of diagnostic criteria in consecutive patients (with “gold” reference standard applied).

Reliability of a radiation-free, noninvasive and computer-assisted assessment of the spine in children with cerebral palsy

PURPOSE

The radiation-free, noninvasive and computer-assisted Spinal Mouse^® (SM) is a reliable and valid measuring instrument for functional analysis of the pediatric spine. The aim of this study was to examine the intra-rater reliability of the SM measurements in children with cerebral palsy (CP) and to investigate differences after a 1 week of the rehabilitation program.

METHODS

A total of 168 SM investigations in the sagittal plane and frontal plane at three measurement times from a sample of 28 children (n = 10 girls, age 9.7 ± 3.1 years) with CP were eligible for evaluation. For the verification of reliability, the measurement results from the first and second measurement times (t1, t2) were used at intervals of 1 day. In addition, differences after the rehabilitation program the patients underwent (t3) were evaluated using the measurement results of the first and third measurements (5-day interval).

RESULTS

The results show good to excellent intra-rater reliability for the SM measurements, both in the sagittal and in the frontal plane (ICC values = 0.69-0.99). Furthermore, significant changes may occur after only 1 week of therapeutic intervention for total spinal inclination (t1: 12.82 ± 5.40, t3: 11.11 ± 5.60, p = 0.014, Cohen's d = 0.43) and spine length (t1: 401.75 ± 69.05, t3: 409.25 ± 63.58, p = 0.030, Cohen's d = 0.43).

CONCLUSIONS

SM can be used to generate reliable values for functional analysis of the spine in children with CP. Furthermore, significant posture differences can be demonstrated by therapeutic interventions, especially in the spine inclination (Inc) and spine length (SL). These slides can be retrieved under Electronic Supplementary Material.

The Effect of Bracing on Spinopelvic Rotation and Psychosocial Parameters in Adolescents with Idiopathic Scoliosis

STUDY DESIGN

Retrospective study.

PURPOSE

To evaluate the effect of bracing on spinopelvic rotation and psychosocial parameters in adolescents with idiopathic scoliosis (AIS).

OVERVIEW OF LITERATURE

Complex three-dimensional deformity in AIS is proposed to influence the spinopelvic parameters and psychosocial condition in adolescents; however, few studies have quantitatively evaluated these parameters.

METHODS

Thirty AIS who were prescribed a brace were included in the study. The patients' standing postero-anterior and total spine radiographs were used to measure the primary curve Cobb angle, vertebral rotation, and pelvic rotation. Apical vertebral rotation (AVR), upper AVR, and lower AVR were measured using the Nash-Moe method. Pelvic rotation was determined using the left-to-right hemipelvic width ratio. The curve pattern was classified as per the Lenke classification system. In all, 14 patients had a type I curve, five had type II, six had type III, one had type IV, and four had type V curves. Brace compliance was subjectively evaluated by interviewing the patients and their parents. The health-related quality of life (HRQOL) and stress level of the recruited patients were assessed using the Brace Questionnaire and Bad Sobernheim Stress Questionnaire, respectively.

RESULTS

The Cobb angle significantly decreased with at least 6 months of brace use. AVR correction changed significantly; however, no such results were observed for upper and lower AVR. Pelvic rotation and psychosocial parameters were not significantly affected by brace use. No statistically significant correlation was observed between brace compliance and curve correction.

CONCLUSIONS

The Cobb angle and AVR are crucial measurements that help evaluate the treatment efficacy in AIS with small curves who undergo brace treatment. HRQOL and pelvic axial rotation are not influenced by the brace treatment.