Side-bending Radiographs Research Articles

Bracing in severe skeletally immature adolescent idiopathic scoliosis: does a holding strategy change the surgical plan?

PurposeThe purpose of the study was to assess the changes in flexibility during night-time bracing in skeletally immature adolescent idiopathic scoliosis (AIS) with curves in the surgical range.Materials and methodsWe included a consecutive cohort of 89 AIS patients with curves ≥ 45° and an estimated growth potential. All patients were eventually treated with fusion surgery, and all patients had side-bending radiographs prior to both bracing and surgery. Curves were classified as structural or non-structural curves according to Lenke at both timepoints.ResultsThe main curve progressed by a mean of 12 ± 10° and the secondary curve by 8 ± 8°. Flexibility of the main curve decreased from 50 ± 19% to 44 ± 19% (p = 0.001) and the underlying curve from 85 ± 21% to 77 ± 22% (p = 0.005). In 69 patients (79%), the Lenke category did not progress during bracing. In 14 patients (15%), the progression in Lenke type occurred in the thoracic region (i.e., Lenke type 1 to type 2), while six patients (7%) progressed in the lumbar region (i.e., type 1 to type 3).In the 69 patients that did not progress, we found that the last touched vertebra moved distally by one or two levels in 26 patients.ConclusionsThis is the first study to describe that curve flexibility decreases during bracing in severe AIS. However, this had only a modest impact on the surgical strategy. Bracing as a holding strategy can be applied, but the risk of losing flexibility in the lumbar spine should be outweighed against the risks of premature fusion surgery.

Prediction of postoperative curve correction based on the supine radiographs for adult idiopathic scoliosis patients

BACKGROUND CONTEXTPreoperative supine radiographs are mandatory in the new adult idiopathic scoliosis (AdIS) classification. Supine radiographs are easily reproducible and highly predictive of side bending radiographs. However, few studies evaluated the use of supine radiographs in predicting postoperative curve correction after posterior spinal fusion (PSF) in AdIS. PURPOSETo investigate the use of supine and side bending (SB) radiographs in predicting postoperative curve correction in AdIS patients who underwent PSF. STUDY DESIGNRetrospective study. PATIENT SAMPLEA total of 93 AdIS patients who underwent PSF between 2022 and 2023 were included. OUTCOME MEASURESDemographic data were age, gender, height, weight, body mass index (BMI), Risser grade, Lenke curve types and Cobb angles. Main outcome measures were preoperative and immediate postoperative Cobb angle (proximal thoracic [PT], main thoracic [MT] and thoracolumbar/lumbar [TL/L] curves), Supine Cobb angle and Flexibility rate (PT, MT and TL/L), and Correction rate (PT, MT and TL/L). METHODSCorrelation study was performed between Supine Cobb angle vs postoperative Cobb angle for PT, MT and TL/L curves. A predictive formula was derived from the correlation plots. RESULTSA total of 93 subjects were included in our study with a median age of 24.7 years and comprised of 80 females (86.0%). Preoperative Supine Cobb angle (r=0.835, r=0.881, r=0.767, p<.001) and preoperative SB Cobb angle (r=0.815, r=0.872, r=0.801, p<.001) showed similar strong positive correlation with postoperative PT, MT and TL/L Cobb angle, but preoperative Supine Cobb angle had slightly stronger correlation in PT and MT, whereas preoperative SB Cobb angle had stronger correlation in TL/L curve. Using the derived predictive formulae, there was a significant, strong, positive correlation between the predicted value and actual value of postoperative standing Cobb angle, (r=0.852, p<.001), with 71.0% of the patients had predicted postoperative Cobb angle from the supine radiographs within 5° of the actual value. CONCLUSIONBoth supine radiographs and side bending radiographs had strong predictability of the postoperative Cobb angle for PT, MT and TL/L curves. In 71.0% of patients, the actual postoperative Cobb angle was within 5° of the predicted postoperative Cobb angle using the predictive formulae.

Comparison of traction, side-bending and dead-hang radiographs in preoperative evaluation and postoperative correction prediction in adolescent idiopathic scoliosis: A retrospective analysis of a novel flexibility radiograph.

A retrospective study comparing traction, dead-hang, and side-bending radiographs in adolescent idiopathic scoliosis to compare the effectiveness of dead-hang radiography in structural and nonstructural curves and evaluate it in terms of postoperative correction prediction. In the surgical correction of adolescent idiopathic scoliosis, flexibility radiographs have an important role in determining fusion levels and in surgical decision-making. Supine bending radiographs are presently considered the gold standard, but their reliability, reproducibility, and standardization along with traction films, are a subject of debate. In our clinic, dead-hang radiographs are also used as an alternative flexibility film. The role of dead-hang radiography against other flexibility radiographs is unknown. A total of 33 patients with adolescent idiopathic scoliosis were evaluated with preoperative standing, lateral, supine traction, dead-hang, supine side-bending, and postoperative standing films. Flexibility and correction rates were assessed. In structural main thoracic (MT) and thoracolumbar/lumbar (TL/L) curves, dead-hang showed significantly higher flexibility compared with traction (P < .001). In MT curves > 60°, dead-hang was superior to side-bending and traction, whereas in MT curves < 50°, side-bending showed more improvement (P < .05). Side-bending showed higher flexibility in TL/L curves < 50° (P < .05). No predictive value was found in structural curves for all 3 radiographs. In nonstructural curves, side-bending films showed over-correction while traction radiographs remained below postoperative correction. Dead-hang radiographs showed very similar flexibility to postoperative correction. Dead-hang radiograph is superior to traction. In MT curves > 60°, dead hang shows greater flexibility than side-bending. Dead-hang technique, which shows equal results with side-bending except in TL/L curves < 50°, is a successful flexibility radiograph and provides predictive value for nonstructural curves in terms of postoperative correction.

Posterior spinal fusion with lowest instrumented vertebra at L4 in idiopathic scoliosis: optimizing radiographic outcomes using pre-operative flexibility radiographs.

In idiopathic scoliosis (IS), there is general agreement ending PSFs at L3 or more cranial is preferred to optimize spinal motion, and extending PSFs to L4 may be necessary; however, this may also cause coronal imbalance or caudal disc wedging post-operatively due to leveling of L4 tilt. The purpose of this study was to identify a pre-operative radiographic measurement, which can be used to quantify the optimal amount of L4 tilt for ideal post-operative radiographic alignment. The study was a retrospective analysis of IS patients who underwent PSF to L4, with minimum 2-year follow-up post-operatively. Optimal outcome was defined by coronal balance, and L4-5 and L5-S1 disc wedging. 44 patients (84% females, mean age 13.6years) were included. Analysis of pre-operative flexibility radiographs determined only the L5 tilt on the right side-bending (RSB) radiograph correlated with optimal outcome 2 (p = 0.03). To confirm the validity, the RSB value was subtracted from the post-operative C7-L4 tilt and the odds ratio analysis which was significantly correlated with optimal outcome 1 at final follow-up (OR 1.04, 95% CI 1-1.09). In PSF to L4 for IS, L5 tilt measured from the pre-operative supine RSB radiograph can be used to optimize radiographic outcomes. Matching the pre-operative L5 tilt on RSB radiograph by leaving L4 tilted at the end of the PSF construct during surgery, quantified by the C7-L4 acute angle tilt, appears to be a useful method to achieve the desired post-operative alignment.

Thoracoscopic Anterior Vertebral Body Tethering in Lenke Type-1 Right Adolescent Idiopathic Scoliosis.

Vertebral body tethering (VBT) is indicated for skeletally immature patients with progressive adolescent idiopathic scoliosis (AIS) who have failed or are intolerant of bracing and who have a major coronal curve of 40° to 65°. The vertebral body must be structurally and dimensionally adequate to accommodate screw fixation, as determined radiographically. The best indication for VBT is a flexible single major thoracic curve with nonstructural compensating lumbar and proximal thoracic curves (Lenke 1A or 1B). VBT allows for progressive correction of the deformity without spinal fusion by utilizing a minimally invasive fluoroscopic technique. The procedure for a right thoracic curve is performed with use of a right thoracoscopic approach with the patient in the left lateral decubitus position. The thoracoscope is introduced through a portal at the apex of the curvature in the posterior axillary line. Instrument portals are created lateral to each vertebral body in the mid-axillary line. Screws are inserted into each vertebral body under biplanar fluoroscopic control and with intraoperative neuromonitoring. An electroconductivity probing device, while not mandatory, is routinely utilized at our practice. The tether is attached to the most proximal screw of the construct, and then reduction is obtained sequentially by tensioning the tether from one vertebral screw to the next. Bracing is the gold-standard treatment for progressive AIS involving the immature spine. The most commonly utilized surgical treatment is posterior spinal fusion (PSF), which should be considered when the major coronal curve exceeds 45°. PSF has proven to be a dependable technique to correct scoliotic deformities. It has a low complication rate and good long-term outcomes. However, concerns exist regarding the stiffness conferred by PSF and the long-term effects of adjacent segment disease. Thus, interest had developed in non-fusion solutions for AIS correction. VBT utilizes the Hueter-Volkmann principle to guide growth and correct deformity. Compressive forces applied to the convexity of the deformity by a polyethylene tether allow the patient's growth to realign the spine. Intraoperative correction triggers growth modulation, and most of the modulation seems to occur during the first 12 months postoperatively. The best results have been seen with a short Lenke type-1A curve in a patient with closed triradiate cartilage, a Risser 3 or lower (ideally Risser 0) iliac apophysis, and a flexible curve characterized by a 50% reduction of the major coronal curve angle on side-bending radiographs. In 57 immature patients with a Lenke type-1A or 1B curve (i.e., a 30° to 65° preoperative Cobb angle), Samdani et al.3 found a main thoracic Cobb angle reduction from 40° ± 7° preoperatively to 19° ± 13° at 2 years after VBT. In the sagittal plane, the T5-T12 kyphosis measured 15° ± 10° preoperatively, 17° ± 10° postoperatively, and 20° ± 13° at 2 years. No major neurologic or pulmonary complications occurred. A total of 7 (12.3%) of the 57 patients underwent surgical revision, including 5 for overcorrection and 2 to span additional vertebrae. In a study of 21 skeletally mature patients, Pehlivanoglu et al.4 found that the Cobb angle was reduced from 48° preoperatively to 16° on the first-erect postoperative radiograph and finally to 10° at the latest follow-up (mean, 27.4 months). The 2 main complications of VBT reported in the literature are overcorrection and tether breakage. Both may require revision, which explains the higher rate of revision observed for VBT compared with PSF. Good patient selection is important. VBT is most appropriate in cases of a flexible Lenke type-1A or 1B curve in an immature child before Risser stage 3 and after triradiate cartilage closure.Always monitor and control screw positioning in both anteroposterior and lateral planes fluoroscopically.The screws should be placed parallel to the vertebral end plates or, even better, be angled inferiorly for the upper vertebrae and angled superiorly for the lower vertebrae to decrease the risk of pull-out when tensioning the device and during growth modulation. Less tension on the uppermost and lowermost instrumented vertebrae than at the apex, as controlled by the tensioning device, can also help to limit pull-out. VBT = vertebral body tetheringAIS = adolescent idiopathic scoliosisIONM = intraoperative neuromonitoringPSF = posterior spinal fusionUIV = upper instrumented vertebraLIV = lower instrumented vertebraAP = anteroposteriorK-wire = Kirschner wire.

Comparison of standing, side bending and awake supine manual traction dynamic radiographs for predicting spinal flexibility with postoperative correction rate in adolescent idiopathic scoliosis

Abstract Background: The aim of the study was to compare awake supine manual traction radiograph with standing side bending radiograph in adolescent idiopathic scoliosis (AIS) patients and to analyze, which one among them is the best predictor of spinal flexibility index in varying degrees of AIS curves with minimal to severe Cobb angle. Materials and Methods: AIS patients, who underwent surgery during the period from 2015 to 2018, were retrospectively analyzed. Supine manual traction anteroposterior radiograph were taken with the patient in the supine position, with traction applied by a person with the head halter at the chin and counter traction applied with pelvic belt, leg straps. Patients were divided into three groups A, B, and C based on Cobb angle of the major structural curve. Patients with Cobb angles between 40° to 65°, 65° to 90°, and more than 90° were included in Groups A, B, and C, respectively. Flexibility indices obtained from both traction and bending radiographs were correlated with percent change in Cobb angle correction post-surgery. Statistical analysis was done to find Pearson correlation coefficient (r) between variables and results were tabulated. Results: There were 36, 16, and 16 patients in Group A, B, and C, respectively. The mean age of the cohort was 13.38 years. Group A had a positive correlation to traction radiographs (r = + 0.188, P = 0.455). Group B had a statistically significant positive correlation to bending radiographs (r = + 0.729, P = 0.04). A statistically significant positive correlation with traction radiographs (r = + 0.769, P = 0.016) was seen in Group C. Conclusion: Awake supine manual traction radiographs reveal better flexibility index in severe stiff (Cobb more than 90°) curves. In moderately stiffer curves (Cobb 65°–90°) standing side bending radiographs provide a better flexibility index than traction radiographs. Supine manual traction radiographs should always accompany bending radiographs in evaluating AIS patients, especially with severe stiff curves.

Associated factors and effects of coronal vertebral wedging angle in thoracic adolescent idiopathic scoliosis

BackgroundAdolescent idiopathic scoliosis (AIS) causes vertebral wedging, but associated factors and the impact of vertebral wedging are still unknown. We investigated associated factors and effects of vertebral wedging in AIS using computed tomography (CT). MethodsPreoperative patients (n = 245) with Lenke types-1 and 2 were included. Vertebral wedging, lordosis, and rotation of the apical vertebra were measured by preoperative CT. Skeletal maturity and radiographic global alignment parameters were evaluated. Multiple regression analysis was performed on associated factors for vertebral wedging. Side-bending radiographs were evaluated using multiple regression analysis to calculate the percentage of reduction of Cobb angles to determine curve flexibility. ResultsThe mean vertebral wedging angle was 6.8 ± 3.1°. Vertebral wedging angle was positively correlated with proximal thoracic (r = 0.40), main thoracic (r = 0.54), and thoracolumbar/lumbar curves (r = 0.38). By multiple regression, the central sacral vertical line (p = 0.039), sagittal vertical axis (p = 0.049), main thoracic curve (p = 0.008), and thoracolumbar/lumbar curve (p = 0.001) were significant factors for vertebral wedging. In traction and side-bending radiographs there were positive correlations between curve rigidity and the vertebral wedging angle (r = 0.60, r = 0.59, respectively). By multiple regression, thoracic kyphosis (p < 0.001), lumbar lordosis (p = 0.013), sacral slope (p = 0.006), vertebral wedging angle (p = 0.003), and vertebral rotation (p = 0.002) were significant factors for curve flexibility. ConclusionsVertebral wedging angle was found to be highly correlated to coronal Cobb angle, with larger vertebral wedging indicating less flexibility.

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

Retrospective comparative study. 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). 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. A total of 86 patients were included mean age 14.9years 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. 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.

The clinical role of preoperative fulcrum-bending and supine side-bending radiographs on the prediction of curve correction in adolescent idiopathic scoliosis.

Preoperative curve assessment is important in adolescent idiopathic scoliosis (AIS). Our objective is to clarify the role of side-bending radiographs (SBR) and fulcrum-bending radiographs (FBR) in predicting postoperative Cobb angle in nonstructural and structural curves. Twenty-five consecutive patients with AIS who underwent correction surgery were included. The Cobb angles of structural and nonstructural curves were determined. Cobb angles were measured based on pre- and postoperative standing anteroposterior radiographs of the whole spine. The Cobb angles of SBR and FBR were measured preoperatively. The difference between the Cobb angle at each bending and the preoperative Cobb angle was defined as the predicted correction angle, whereas the difference between the preoperative Cobb angle and postoperative Cobb angle was defined as the surgical correction angle. The correction index was calculated by dividing the surgical correction angle by the predicted correction angle. The difference between the predicted correction angle and surgical correction angle was defined as the prediction error. We compared SBR and FBR for both structural and nonstructural curves in these terms. For both curves, the predicted correction angle of FBR was significantly higher than that of SBR, and the correction index of FBR was significantly lower than that of SBR. Patients with a correction index close to 1 and small prediction error had undergone FBR in the structural curve and SBR in the nonstructural curve. FBR is predictive of postoperative correction angle of the structural curve, whereas SBR is predictive of postoperative correction angle of the nonstructural curve.

Surgical Site Infection Following the Correction of Adolescent Idiopathic Scoliosis With ApiFix: A Retrospective Study Analyzing Its Incidence and Recurrence.

Background and objective ApiFix (OrthoPediatrics, Warsaw, IN) is an internal brace used for the correction of adolescent idiopathic scoliosis (AIS) classified as Lenke 1 or 5 with a Cobb angle of 35-60 degrees that decreases to ≤30 degrees on lateral side-bending radiographs. Since the indications are very specific, it is not a common procedure. Our study aimed to evaluate the incidence of surgical site infection (SSI) and its recurrence following treatment with ApiFix. Materials and methods A retrospective study of 44 cases of AIS treated at our center from 2016 to 2022 with ApifiX was conducted. Two patients who presented with SSI were initially treated with irrigation and debridement (I&D) following antibiotic therapy. Results A total of 44 patients with a mean age of 15.1 years were evaluated. Two of our patients presented with early-onset infection while one of them presented after the end of treatment with a skin ulcer due to septic screw loosening. The removal of the ApiFix implant revealed a pedicle abscess during the screw removal. Conclusions In this study of 44 patients, we observed two cases of infection and one case of reinfection. Given the limited muscle detachment and short operating time needed for Apifix, statistics suggest that the risk of SSIis always present. Further randomized trials are needed to gather more evidence on this subject.

Reliability of Preoperative Supine Versus Bending Radiographs in Estimating the Structural Nature of Curves in EOS.

The study sought to evaluate the utility of a single supine radiograph in determining curve flexibility in early-onset scoliosis (EOS) patients. EOS patients with upright (standing/seated), supine, and side-bending radiographs who underwent spinal deformity surgery were identified. Coronal parameters included: proximal thoracic (PT) curve, main thoracic (MT) curve, and thoracolumbar/lumbar (TL/L) curve. Each radiograph was measured twice by 2 different raters. Correlation coefficients were utilized to investigate associations between the different radiographs. Interrater Correlation Coefficient (ICC) assessed intrarater and interrater reliability. Thirty-seven EOS patients were identified (age at diagnosis: 7.0±2.9y, preoperative age: 13.0±2.9y; 73% female; etiologies: 54% idiopathic, 30% syndromic, and 16% neuromuscular). Supine PT and MT curve measurements were highly associated with corresponding side-bending measurements (PT: r=0.75, P<0.001; MT: r=0.80, P<0.001), and TL/L curves were very highly associated (TL/L: r=0.92, P<0.001). The mean absolute differences between supine and side-bending measurements were PT: 11.3±7.8 degrees, MT: 14.8±8.3 degrees, and TL/L: 16.2±7.6 degrees, where the side-bending was on average smaller than the supine measurement. The intrarater reliabilities were excellent, with an ICC ranging from 0.93 to 0.96 for side-bending films and 0.94 to 0.97 for supine films. The interrater reliability was excellent with ICC value of 0.88 for side-bending films and 0.93 for supine films. A single, preoperative supine radiograph was highly predictive of side-bending radiographs in patients with EOS. Supine curves measured an average of 15 degrees larger than bending curves in the MT and TL/L region. A single supine film may eliminate the need for effort-related, dual side-bending radiographs. Level II-retrospective study.

A comparative study of supine traction, supine side-bending radiographs, and supine MRI to determine coronal flexibility in degenerative lumbar scoliosis patients.

The purpose of this study was to compare curve correction in degenerative lumbar scoliosis using supine traction radiographs, supine side-bending radiographs, and supine MRI. A prospective analysis of Cobb angles from patients diagnosed with degenerative lumbar scoliosis who underwent supine traction radiography (TR), side-bending radiography (SB), and supine MRI. The Cobb angles at thoracic (T), thoracolumbar/lumbar (TL/L), and lumbosacral (LS) levels were measured, and the curvecorrection in percentages compared with standing AP radiography was calculated as corrective flexibility. Differences in curve correction were analyzed. In total, 33 patients with an age range of 50-80years were eligible for inclusion. Traction radiography provided the greatest accuracy in curve correction, with a significant difference from side-bending radiography and supine MRI in T, TL/L, and LS levels (P < 0.001). The difference between side-bending radiography and supine MRI in TL/L and LS levels wasnot significant (P = 0.721, P = 0.654, respectively). A moderate correlation was found between the corrective flexibility of TR and SB at the T level (0.563, P = 0.001), a strong correlation was observed between the corrective flexibility of TR and SB at the TL/L level (0.709, P < 0.001), and at the TL/L level, a moderate correlation was identified between TR and supine MRI corrective flexibility (0.425, P = 0.014). Traction radiographs significantly outperformed side-bending radiographs and supine MRI in terms of access curve flexibility in degenerative lumbar scoliosis.

Freehand power-assisted pedicle screw placement in scoliotic patients: results on 5522 consecutive pedicle screws

Pedicle screws is the current gold standard in spine surgery, achieving a solid tricolumnar fixation which is unreachable by wires and hooks. The freehand technique is the most widely adopted for pedicle screws placing. While freehand technique has been classically performed with manual tools, there has been a recent trend toward the use of power tools. However, placing a pedicle screw remains a technically demanding procedure with significant risk of complications. The aim of this article is to retrospectively evaluate safety and accuracy of free-hand power-assisted pedicle screw placement in a cohort of patients who underwent correction and fusion surgery for scoliosis (both idiopathic and non-idiopathic) in our department. A retrospective review of all patients with scoliosis who underwent surgery and received a postoperative CT scan in our department in a 9-year period was undertaken. Screw density, number and location of pedicle screws were measured using pre and postoperative full-length standing and lateral supine side-bending radiographs. Then, postoperative CT scan was used to assess the accuracy of screw placement according to Gertzbein-Robbins scale. Malpositioned screws were divided according to their displacement direction. Finally, intra and postoperative neurological complications and the need for revision of misplaced screws were recorded. A total of 205 patients were included, with a follow-up of 64.9 ± 38.67 months. All constructs were high density (average density 1.97 ± 0.04), and the average number of fusion levels was 13.72 ± 1.97. A total of 5522 screws were placed: 5308 (96.12%) were grade A, 141 (2.5%) grade B, 73 (1.32%) grade C. Neither grade D nor grade E trajectories were found. The absolute accuracy (grade A) rate was 96.12% (5308/5522) and the effective accuracy (within the safe zone, grade A + B) was 98.6% (5449/5522). Of the 73 misplaced screws (grade C), 59 were lateral (80.80%), 8 anterior (10.95%) and 6 medial (8.22%); 58 were in convexity, while 15 were in concavity (the difference was not statistically significant, p = 0.33). Intraoperatively, neither neurological nor vascular complications were recorded. Postoperatively, 4 screws needed revision (0.072% of the total): Power-assisted pedicle screw placing may be a safe an accurate technique in the scoliosis surgery, both of idiopathic and non-idiopathic etiology. Further, and higher quality, research is necessary in order to better assess the results of this relatively emerging technique.

Measurable Lumbar Motion Remains 1 Year After Vertebral Body Tethering.

Vertebral body tethering (VBT) is growing in popularity for skeletally immature patients with scoliosis because of presumed preservation of spinal motion. Although results have shown preserved thoracic motion, there is minimal data to support motion over the lumbar instrumented segments after VBT. The purpose of this study was to analyze the range of motion of the thoracolumbar and lumbar spine after lumbar VBT. Retrospective review of patients treated with lumbar VBT underwent low-dose biplanar flexion-extension and lateral bending radiographs at 1 year after surgery to assess motion. Coronal motion at 1 year was compared with preoperative side-bending radiographs. The angle subtended by the screws at the upper instrumented vertebra and lower instrumented vertebra was measured on left-bending and right-bending radiographs to evaluate the coronal arc of motion and was compared with preoperative values over the same levels measured from the end plates. At 1 year postoperatively, the sagittal angle was measured over the instrumented levels on flexion and extension radiographs. Of the 71 scoliosis patients who underwent VBT at our center eligible for 1-year follow-up, 20 had lumbar instrumentation, all of whom had lumbar bending films available at 1 year after surgery. Seven patients had both thoracic and lumbar VBT on the same day and 13 had lumbar or thoracolumbar tether only. Mean age was 13.5±1.9 years. Mean preoperative major coronal curve measured 52+8 degrees (range: 42 to 70) and mean 27 degrees (range: 13 to 40) at latest follow-up. Mean levels instrumented was 8 (range: 5 to 12), with the lowest instrumented level typically L3 (N=14). The mean preoperative coronal arc of motion over the instrumented segments was 38±13 degrees (range: 19 to 73 degrees) and decreased after surgery to a mean arc of 17±7 degrees (range: 7 to 31 degrees). However, 19 of the 20 (95%) had at least a 10-degree coronal arc of motion. Patients maintained on average 46% (range: 22% to 100%) of their preoperative coronal arc of lumbar motion over the instrumented lumbar segments. On flexion-extension lateral radiographs taken at 1 year postoperatively, there was a mean postoperative arc of motion of 30±13 degrees. Lumbar VBT resulted in preserved flexion and extension motion at 1 year postoperatively. We also noted some preserved coronal plane motion, but this was decreased compared with preoperative values by ~50%. These findings provide proof of concept that some spinal motion is preserved after lumbar VBT in contrast to lumbar fusion where no motion is retained over the instrumented segments.

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

BackgroundDetermining 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. MethodsThirteen 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. ResultsThe 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). ConclusionThe 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 evidenceII; non-randomized controlled comparative study.

Impact of the flexibility of the spinal deformity on low back pain and disc degeneration in adult patients nonoperatively treated for adolescent idiopathic scoliosis with thoracolumbar or lumbar curves.

To evaluate the impact of the flexibility of thoracolumbar or lumbar (TL/L) curves on low back pain (LBP) and disc degeneration in adult patients nonoperatively treated for adolescent idiopathic scoliosis (AIS). Forty-seven adult patients (46 women; mean age, 40.5years) nonoperatively treated for AIS with TL/L curves were included. The patients completed radiological examinations, magnetic resonance imaging, and a questionnaire survey for LBP evaluation. The flexibility of the spinal deformity was evaluated using supine side-bending radiographs. Radiographic measurements were correlated with scores for LBP and disc degeneration. The average magnitude and flexibility of the TL/L curve were 49.0° and 56%, respectively. The magnitudes of the TL/L curve and disc wedging were significantly correlated with LBP (|r|= 0.3-0.4). The flexibility of the TL/L curve and disc wedging, and the lumbar lateral range of motion (ROM) were significantly correlated with LBP and disc degeneration (|r|= 0.3-0.5). After controlling for the magnitudes of the TL/L curve and disc wedging, the flexibility of L4/5 disc wedging and the lumbar lateral ROM remained significantly correlated with the Scoliosis Research Society-22 pain score (partial correlation coefficient [r'] = 0.5 and 0.3), Oswestry Disability Index (-0.3 and -0.3), and disc degeneration (-0.4 and 0.3). In AIS patients with TL/L curves, the flexibility of L4/5 disc wedging and the lumbar lateral ROM were significantly correlated with LBP and disc degeneration, independent of the magnitudes of the coronal deformities. Our findings indicate that maintaining or improving lumbar flexibility may be beneficial for preventing or treating LBP.

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.

Impact of Supine Radiographs to Assess Curve Flexibility in the Treatment of Adolescent Idiopathic Scoliosis.

Study Design:Retrospective cohort study.Objectives:The purpose of the study is to evaluate the role of supine radiographs in determining flexibility of thoracic and thoracolumbar curves.Methods:Ninety operative AIS patients with 2-year follow-up from a single institution were queried and classified into MT structural and TL structural groups. Equations were derived using linear regression to compute cut-off values for MT and TL curves. Thresholds were externally validated in a separate database of 60 AIS patients, and positive and negative predictive values were determined for each curve.Results:MT supine values were highly predictive of MT side-bending values (TL group: 0.63, P < 0.001; MT group: 0.66, P = 0.006). Similarly, TL supine values were highly predictive of TL side-bending values (TL group: 0.56, P = 0.001 MT group: 0.68, P = 0.001). From our derived equations, MT and TL curves were considered structural on supine films if they were ≥ 30° and 35°, respectively. Contingency table analysis of external validity sample showed that supine films were highly predictive of structurality of MT curve (Sensitivity = 0.91, PPV = 0.95, NPV = 0.81) and TL curve (Sensitivity = 0.77, PPV = 0.81, NPV = 0.94). ROC analysis revealed that the area under curve for MT structurality from supine films was 0.931 (SEM: 0.03, CI: 0.86-0.99, P < 0.001) and TL structurality from supine films was 0.922 (SEM: 0.03, CI- 0.84-0.98, P < 0.001).Conclusions:A single preoperative supine radiograph is highly predictive of side-bending radiographs to assess curve flexibility in AIS. A cut-off of ≥ 30° for MT and ≥ 35° for TL curves in supine radiographs can determine curve structurality.

Preoperative supine traction radiographs often result in higher Lenke classifications than supine bending radiographs in adolescent idiopathic scoliosis.

Retrospective chart and radiographic review. The purpose of this study is to determine if both traction and side-bending radiographs yield the same Lenke classification. Supine side-bending radiographs are used to evaluate curve flexibility and assign Lenke classification in Adolescent Idiopathic Scoliosis (AIS). Supine traction radiographs are another tool used by treating surgeons to gauge flexibility and appropriate levels for spinal fusion in AIS. Retrospective chart and radiographic review were performed on AIS patients that underwent a posterior spinal fusion from 2008 to 2017. Cobb angles and Lenke classifications were determined on all upright posterioanterior (PA) spine radiographs, supine traction radiographs, and four supine bending radiographs. Statistical analysis using independent t tests and chi-square tests as appropriate were compared between patients with or without discordant Lenke classifications with p value set at < 0.05 for statistical significance. 184 patients met inclusion criteria, 36 males and 148 females. The average Cobb angle for the proximal thoracic (PT) curve was 27.2°, main thoracic (MT) curve was 60.5°, and thoracolumbar/lumbar (TL/L) curve was 48.0°. Significantly less curve correction was found with supine traction radiographs compared with bending radiographs: PT (23.1° vs 18.9°, p < 0.001), MT (38.9° vs 37.9°, p = 0.015), and TL/L (25.9° vs. 18.0°, p < 0.001). Lenke Classification was found concordant in 151/184 (82.1%). Traction views in the discordant Lenke classification group demonstrated less curve correction than those in the concordant group: PT (27.4° vs. 22.1°, p = 0.011), MT (45.3° vs. 37.5°, p < 0.001), and TL/L (29.3° vs 25.1°, p = 0.019). Supine traction and supine bending radiographs provided a concordant Lenke classification 82.1% of the time. However, supine traction radiographs demonstrate less curve correction, a higher Lenke classification, and underestimated the TL/L curve correction to a greater degree. A single supine traction film is not an adequate substitute to side-bending radiographs when determining Lenke classification in patients with Adolescent Idiopathic Scoliosis. III.

Factors related to postoperative coronal imbalance in adult lumbar scoliosis.

The object of this study was to analyze the prevalence of postoperative coronal imbalance (CIB) and related factors in patients with adult lumbar scoliosis. This was a retrospective single-center study of data from patients with adult spinal deformity (ASD) who had undergone corrective surgery performed by a single surgeon between 2009 and 2017. The inclusion criteria were as follows: 1) age at surgery > 40 years, 2) Cobb angles of the thoracolumbar/lumbar (TL/L) curve > 40°, 3) upper instrumented vertebra of T9 or T10, 4) lowest instrumented vertebra of L5 or the pelvis, and 5) minimum 2-year follow-up period. Radiographic parameters were measured before surgery, 2 weeks after surgery, and at the latest follow-up. Curve flexibility was also assessed using side bending radiographs. Clinical outcomes were evaluated using the 22-Item Scoliosis Research Society Outcomes Questionnaire (SRS-22) and the SF-36. CIB was considered to have occurred if the C7 plumbline was more than 2.5 cm lateral to the central sacral vertical line (i.e., coronal vertical axis [CVA] > 2.5 cm) at the final follow-up. Parameters between the patients with (CIB group) and without (coronal balance [CB] group) CIB were compared, and factors related to CIB were evaluated. From among 66 consecutively treated ASD patients, a total of 37 patients (mean age at surgery 66.3 years, average follow-up 63 months) met the study inclusion criteria. CIB was found in 6 patients at the final follow-up (16.2%), and the CVA of all patients in the CIB group shifted to the convex side of the TL/L curve. A comparative analysis between the CB and CIB groups, respectively, at the final follow-up indicated the following factors were related to CIB: lumbosacral (LS) curve, 11.0°/16.5° (p = 0.02); LS correction rate (CR), 61%/47% (p = 0.02); and CR ratio (LS vs TL/L), 0.93/0.67 (p = 0.0002). Regarding clinical outcomes, the satisfaction domain of the SRS-22 (CB 4.4 vs CIB 3.5) showed a significant difference between the CIB and CB groups (p = 0.02), and patients in the CB group tended to score better on the pain domain (CB 4.3 vs CIB 3.7), but the difference was not significant (p = 0.06). Postoperative CIB negatively impacted patients' HRQOL. An imbalanced correction ratio between the TL/L and LS curves may cause postoperative CIB. Therefore, adequate correction of the LS curve may prevent postoperative CIB.