Evaluation of Vertebral derotation in the correction of Adolescent Idiopathic Scoliosis

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Essam A Emara ◽  
Hossam S Taha ◽  
Walid A AbdelGhany ◽  
Ahmed H AbouZeid ◽  
Mohammad A Yusuf
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Skeletal Maturity ◽  
Operating Time ◽  
Sagittal Profile ◽  
Correction Rate ◽  
Curve Magnitude ◽  
The Mean ◽  
Flexibility Index

Abstract Background Adolescent idiopathic scoliosis (AIS) represents a complex three-dimensional deformity. The rotation of the apical vertebrae is primarily responsible for the rib hump that represents the main cosmetic problem for adolescent patients. Correcting rotational deformity and maintaining the normal sagittal profile of the spine is more important than onlycorrecting coronal deformity. Aim of the Work to evaluate the efficacy of vertebral derotation using Single Concave Rod Rotation (SCRR) maneuver in the treatment of patients with Adolescent Idiopathic Scoliosis (AIS) by clinical and radiological follow up for 1 year. Patients and Methods This prospective analysis was done on 30 patients with AIS, who underwent one stage posterior only corrective surgery with SCRR maneuver between 2016 and 2019 at Ain Shams University Hospitals in order to correct their deformities. All patients included in this study had idiopathic curve between 40 and 80 degrees, with flexibility index < 50%, and their ages were between 10 and skeletal maturity. Results Compared to the results obtained by other studies using the same technique, our study included patients with relatively large curve magnitude and the lowest flexibility index, had average coronal correction rate by about 65.5% and minimal correction loss during follow up (-1°). Furthermore, our study included the largest mean preoperative RA. The axial correction rate was average (32.7%) and has the lowest complication rate and better clinical outcome and patient satisfaction among other studies that used SCRR maneuver. However, the mean operating time in our series in the present study was longer than the mean operating time in the literature. The mean amount of blood loss in our study was more than the mean amount in other studies. Conclusion Simple concave rod rotation is a good option for correction of the deformed curve in AIS. We can state that simple concave rod rotation with pedicle screw instrumentation and without the use of DVD maneuver could successfully correct both coronal and axial deformity with minimal complication. Adding DVD technique offers a better correction of apical vertebra rotation.

scholarly journals Predictability of Coronal Curve Flexibility in Postoperative Curve Correction in Adolescent Idiopathic Scoliosis: The Effect of the Sagittal Profile

2019 ◽  
Vol 10 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Søren Ohrt-Nissen ◽  
Hideki Shigematsu ◽  
Jason Pui Yin Cheung ◽  
Keith D. K. Luk ◽  
Dino Samartzis
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Thoracic Kyphosis ◽  
Clinical Decision Making ◽  
Sagittal Profile ◽  
Curve Correction ◽  
Sagittal Vertical Axis ◽  
Flexibility Index

Study Design: Retrospective cohort study. Objectives: To assess how the thoracic kyphosis affects the ability of the fulcrum bending radiograph (FBR) to predict the coronal thoracic curve correction. Methods: A retrospective study of prospectively collected data was conducted of 107 consecutive patients with thoracic adolescent idiopathic scoliosis (AIS) treated with a standard screw-fixation protocol. Radiographic variables were assessed preoperatively and at 2-year follow-up. Curve flexibility was determined based on the FBR and the Fulcrum Bending Flexibility Index (FBCI). Radiographic variables included preoperative Cobb angle, T5-T12 kyphosis, T12-S1 lordosis, sagittal vertical axis, list, T1-T12 length, truncal shift, and radiographic shoulder height. Patients were also categorized as hypo-, normo-, or hyperkyphotic. Results: Based on multivariate modeling, an increase in FBR Cobb angle and thoracic kyphosis were significantly associated with an increase in FBCI (increased mismatch between the FBR and postoperative Cobb angles) at 2-year follow-up ( P < 0.001). In patients with hyperkyphosis, a longer instrumented length existed despite similar curve size and shorter curve length than the hypo- and normokyphotic groups. Based on these findings, we developed a new predictive postoperative curve correction index, known as the Multiprofile Flexibility Index (MFI). Conclusions: Our results show that an increase in preoperative thoracic kyphosis is associated with an increased difference between the preoperative coronal curve flexibility and the postoperative coronal curve correction. Our findings broaden the understanding of curve flexibility and indicate that selection of fusion levels may need to take into consideration the sagittal profile to improve clinical decision making and optimize outcome.

scholarly journals Surgical management of moderate adolescent idiopathic scoliosis with a fusionless posterior dynamic deformity correction device: interim results with bridging 5–6 disc levels at 2 or more years of follow-up

2020 ◽  
Vol 32 (5) ◽  
pp. 748-754 ◽  
Author(s):  
Yizhar Floman ◽  
Ron El-Hawary ◽  
Michael A. Millgram ◽  
Baron S. Lonner ◽  
Randal R. Betz
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Deformity Correction ◽  
Successful Outcome ◽  
Inclusion Criteria ◽  
Major Curve ◽  
Curve Magnitude ◽  
The Mean

OBJECTIVEA posterior dynamic deformity correction (PDDC) system was used to correct adolescent idiopathic scoliosis (AIS) without fusion. The preliminary outcomes of bridging only 3–4 discs in patients with variable curve severity have previously been reported. This paper examines a subgroup of patients with the authors’ proposed current indications for this device who were also treated with a longer construct.METHODSInclusion criteria included a single AIS structural curve between 40° and 60°, curve flexibility ≤ 30°, PDDC spanning 5–6 levels, and minimum 2-year follow-up. A retrospective review was conducted and demographic and radiographic data were recorded. A successful outcome was defined as a curve magnitude of ≤ 30° at final follow-up. Any serious adverse events and reoperations were recorded.RESULTSTwenty-two patients who met the inclusion criteria were operated on with the PDDC in 5 medical centers. There were 19 girls and 3 boys, aged 13–17 years, with Risser grades ≥ 2. Thirteen had Lenke type 1 curves and 9 had type 5 curves. The mean preoperative curve was 47° (range 40°–55°). At a minimum of 2 years’ follow-up, the mean major curve measured 25° (46% correction, p < 0.05). In 18 (82%) of 22 patients, the mean final Cobb angle measured ≤ 30° (range 15°–30°). Trunk shift was corrected by 1.5 cm (range 0.4–4.3 cm). The mean minor curve was reduced from 27° to 17° at final follow-up (35% correction, p < 0.05). For Lenke type 1 patterns, the mean 2D thoracic kyphosis was 24° preoperatively versus 27° at final follow-up (p < 0.05), and for Lenke type 5 curves, mean lumbar lordosis was 47° preoperatively versus 42° at final follow-up (p < 0.05). The mean preoperative Scoliosis Research Society-22 questionnaire score improved from 2.74 ± 0.3 at baseline to 4.31 ± 0.4 at 2 years after surgery (p < 0.0001). The mean preoperative self-image score and satisfaction scores improved from preoperative values, while other domain scores did not change significantly. Four patients (18%) underwent revision surgery because of nut loosening (n = 2), pedicle screw backup (n = 1), and ratchet malfunction (n = 1).CONCLUSIONSIn AIS patients with a single flexible major curve up to 60°, the fusionless PDDC device achieved a satisfactory result as 82% had residual curves ≤ 30°. These findings suggest that the PDDC device may serve as an alternative to spinal fusion in select patients.

Sanders stage 7b: Using the appearance of the ulnar physis improves decision-making for brace weaning in patients with adolescent idiopathic scoliosis

2021 ◽  
Vol 103-B (1) ◽  
pp. 141-147
Author(s):  
Prudence Wing Hang Cheung ◽  
Jason Pui Yin Cheung
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Skeletal Maturity ◽  
Skeletal Maturation ◽  
Complete Fusion ◽  
Accurate Assessment ◽  
Distal Ulna ◽  
Exact Test ◽  
Arm Span ◽  
The Mean

Aims The aim of this study was to investigate whether including the stages of ulnar physeal closure in Sanders stage 7 aids in a more accurate assessment for brace weaning in patients with adolescent idiopathic scoliosis (AIS). Methods This was a retrospective analysis of patients who were weaned from their brace and reviewed between June 2016 and December 2018. Patients who weaned from their brace at Risser stage ≥ 4, had static standing height and arm span for at least six months, and were ≥ two years post-menarche were included. Skeletal maturity at weaning was assessed using Sanders staging with stage 7 subclassified into 7a, in which all phalangeal physes are fused and only the distal radial physis is open, with narrowing of the medial physeal plate of the distal ulna, and 7b, in which fusion of > 50% of the medial growth plate of distal ulna exists, as well as the distal radius and ulna (DRU) classification, an established skeletal maturity index which assesses skeletal maturation using finer stages of the distal radial and ulnar physes, from open to complete fusion. The grade of maturity at the time of weaning and any progression of the curve were analyzed using Fisher’s exact test, with Cramer’s V, and Goodman and Kruskal’s tau. Results We studied a total of 179 patients with AIS, of whom 149 (83.2%) were female. Their mean age was 14.8 years (SD 1.1) and the mean Cobb angle was 34.6° (SD 7.7°) at the time of weaning. The mean follow-up was 3.4 years (SD 1.8). At six months after weaning, the rates of progression of the curve for patients weaning at Sanders stage 7a and 7b were 11.4% and 0%, respectively for those with curves of < 40°. Similarly, the rates of progression of the curve for those being weaned at ulnar grade 7 and 8 using the DRU classification were 13.5% and 0%, respectively. The use of Sanders stages 6, 7a, 7b, and 8 for the assessment of maturity at the time of weaning were strongly and significantly associated (Cramer’s V 0.326; p = 0.016) with whether the curve progressed at six months after weaning. Weaning at Sanders stage 7 with subclassification allowed 10.6% reduction of error in predicting the progression of the curve. Conclusion The use of Sanders stages 7a and 7b allows the accurate assessment of skeletal maturity for guiding brace weaning in patients with AIS. Weaning at Sanders stage 7b, or at ulnar grade 8 with the DRU classification, is more appropriate as the curve did not progress in any patient with a curve of < 40° immediately post-weaning. Thus, reaching full fusion in both distal radial and ulnar physes (as at Sanders stage 8) is not necessary and this allows weaning from a brace to be initiated about nine months earlier. Cite this article: Bone Joint J 2021;103-B(1):141–147.

scholarly journals Patterns of coronal and sagittal deformities in adolescent idiopathic scoliosis

2021 ◽  
Author(s):  
Trixie Mak ◽  
Prudence Wing Hang Cheung ◽  
Teng Zhang ◽  
Jason Pui Yin Cheung
Keyword(s):  
Quality Of Life ◽  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Sagittal Profile ◽  
Sacral Slope ◽  
Pelvic Parameters ◽  
Curve Magnitude ◽  
Sagittal Parameters

Abstract Background: Thoracic scoliosis has been shown to be associated with hypokyphosis in adolescent idiopathic scoliosis (AIS). However, the relationship of sagittal spino-pelvic parameters with different coronal curve patterns and their influence on patient-perceived quality of life is unknown. This study aims to determine the association between coronal and sagittal malalignment in patients with AIS and to determine their effects on SRS-22r scores. Methods: A cross-sectional study was conducted on 1054 consecutive patients with AIS. The coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) were measured on standing radiographs. The coronal Cobb angle (mild: 10-20°; moderate: >20-40°; severe: >40°) and PI (low: <35°; average: 35-50°; high: >50°) were divided into 3 sub-groups for comparison. Relationship between coronal curve magnitudes and sagittal parameters was studied as was their association with SRS-22r scores. Results: Low PI had smaller SS (30.1±8.3° vs 44.8±7.7°; p<0.001), PT (-0.3±8.1° vs 14.4±7.5°; p<0.001), and LL (42.0±13.2° vs 55.1±10.6°; p<0.001), negative PI-LL mismatch (-12.1±13.1° vs 4.1±10.5°; p<0.001) as compared to large PI. There were no significant relationships with PI and TK (p=0.905) or curve magnitude (p=0.431). No differences in sagittal parameters were observed for mild, moderate or severe coronal Cobb angles. SRS-22r scores only correlated with coronal Cobb angle and larger Cobb angles were negatively correlated with the function, appearance and pain domains. Conclusions: The sagittal profile for AIS is associated with the pelvic parameters especially PI but not with the coronal curve pattern. All patients have a similar TK regardless of coronal curve type. However, it appears that the coronal deformity is a greater influence on quality of life outcomes especially those >40°.

The impact of segmental and en bloc derotation maneuvers on scoliosis correction and rib prominence in adolescent idiopathic scoliosis

2012 ◽  
Vol 16 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Steven W. Hwang ◽  
Amer F. Samdani ◽  
Patrick J. Cahill
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Blood Loss ◽  
Idiopathic Scoliosis ◽  
Sagittal Profile ◽  
Apparent Difference ◽  
En Bloc ◽  
Operative Duration ◽  
Concurrent Use ◽  
The Mean ◽  
The Impact

Object Idiopathic scoliosis is a pathological process influencing the spinal column in 3 dimensions. Initial surgical treatment focused primarily on correction in the coronal plane, and with improved instrumentation, increasing attention has targeted balancing the sagittal profile. Newer surgical techniques now permit operative corrective forces to also directly address axial rotation. Although several technical variations of direct vertebral body derotation (DVBD) have been devised, no studies have compared outcomes from the differing techniques. The purpose of this study was to describe and compare the differences between segmental and en bloc DVBD. Methods A large prospectively collected database was queried for patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion and for whom there was a minimum of 2 years of follow-up. In all patients some type of DVBD maneuver was performed (segmental, en bloc, or both). Any patients with concurrent thoracoplasties were excluded. Results The authors identified 188 patients, of whom 120 underwent segmental derotation, 17 en bloc derotation, and 51 both. No significant radiographic or clinical differences existed among the groups preoperatively. The mean preoperative thoracic curve in the entire cohort was 53.1° ± 14.1° and the mean thoracic rib prominence was 14.0° ± 5.5°, whereas the respective postoperative values were 19.3° ± 8.3° and 7.2° ± 4.0°. No significant difference was identified between the various techniques postoperatively, either. However, when comparing intraoperative variables, significant differences were found for operative duration (p = 0.0001), estimated blood loss (p = 0.0081), and volume of blood transfusions (p = 0.041). Conclusions Although each surgical technique of DBVD may have theoretical benefits and risks, no apparent difference in outcomes was observed between techniques. The concurrent use of both techniques was associated with increased blood loss and operative duration without any appreciable benefit. The surgeon should adopt the derotation technique with which he or she is most comfortable, but concurrent use of both does not appear to improve results.

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

2021 ◽  
pp. 219256822110325
Author(s):  
Sachiko Kawasaki ◽  
Prudence Wing Hang Cheung ◽  
Hideki Shigematsu ◽  
Masato Tanaka ◽  
Yuma Suga ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Curve Progression ◽  
Brace Treatment ◽  
Correction Rate ◽  
Angle Correction ◽  
Clinically Significant ◽  
Deterioration Group

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.

scholarly journals Patterns of coronal and sagittal deformities in adolescent idiopathic scoliosis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Trixie Mak ◽  
Prudence Wing Hang Cheung ◽  
Teng Zhang ◽  
Jason Pui Yin Cheung
Keyword(s):  
Quality Of Life ◽  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Sagittal Profile ◽  
Sacral Slope ◽  
Pelvic Parameters ◽  
Curve Magnitude ◽  
Sagittal Parameters

Abstract Background Thoracic scoliosis has been shown to be associated with hypokyphosis in adolescent idiopathic scoliosis (AIS). However, the relationship of sagittal spino-pelvic parameters with different coronal curve patterns and their influence on patient-perceived quality of life is unknown. This study aims to determine the association between coronal and sagittal malalignment in patients with AIS and to determine their effects on SRS-22r scores. Methods A cross-sectional study was conducted on 1054 consecutive patients with AIS. The coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) were measured on standing radiographs. The coronal Cobb angle (mild: 10–20°; moderate: > 20–40°; severe: > 40°) and PI (low: < 35°; average: 35–50°; high: > 50°) were divided into 3 sub-groups for comparison. Relationship between coronal curve magnitudes and sagittal parameters was studied as was their association with SRS-22r scores. Results Low PI had smaller SS (30.1 ± 8.3° vs 44.8 ± 7.7°; p < 0.001), PT (− 0.3 ± 8.1° vs 14.4 ± 7.5°; p < 0.001), and LL (42.0 ± 13.2° vs 55.1 ± 10.6°; p < 0.001), negative PI-LL mismatch (− 12.1 ± 13.1° vs 4.1 ± 10.5°; p < 0.001) as compared to large PI. There were no significant relationships with PI and TK (p = 0.905) or curve magnitude (p = 0.431). No differences in sagittal parameters were observed for mild, moderate or severe coronal Cobb angles. SRS-22r scores only correlated with coronal Cobb angle and larger Cobb angles were negatively correlated with the function, appearance and pain domains. Conclusions The sagittal profile for AIS is associated with the pelvic parameters especially PI but not with the coronal curve pattern. All patients have a similar TK regardless of coronal curve type. However, it appears that the coronal deformity is a greater influence on quality of life outcomes especially those > 40°.

scholarly journals Higher pedicle screw density does not improve curve correction in Lenke 2 adolescent idiopathic scoliosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Timothy J. Skalak ◽  
Joel Gagnier ◽  
Michelle S. Caird ◽  
Frances A. Farley ◽  
Ying Li
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Curve Correction ◽  
Major Curve ◽  
Curve Magnitude ◽  
Screw Density ◽  
Implant Density ◽  
Lenke 2

Abstract Purpose Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS. Methods We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow-up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis. Results Thirty patients (21 females, 9 males) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11–17 years), and median follow-up was 2.8 years (IQR 2.1–4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis. Conclusions Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude. Level of evidence Level III, retrospective observational

scholarly journals Postoperative translation of the upper instrumented vertebra in thoracic adolescent idiopathic scoliosis

2018 ◽  
Vol 22 (6) ◽  
pp. 694-700 ◽  
Author(s):  
Katsuhisa Yamada ◽  
Hideki Sudo ◽  
Kiyoshi Kaneda ◽  
Yasuhiro Shono ◽  
Yuichiro Abe ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Pulmonary Function ◽  
Research Society ◽  
Forced Expiratory Volume ◽  
Postoperative Results ◽  
Scoliosis Research Society ◽  
Correction Rate ◽  
Upper Instrumented Vertebra

OBJECTIVEThe aim of this retrospective study was to analyze the influence of upper instrumented vertebra (UIV) translation from the C7 plumb line (C7PL) on the long-term postoperative results of patients with main thoracic (MT) adolescent idiopathic scoliosis (AIS).METHODSTwenty-five patients had been treated surgically for AIS with a Lenke type 1 curve and had been followed up for a mean period of 18.2 years. Radiographic parameters, pulmonary function measurements, and clinical outcomes were compared between the patients (n = 15) with UIV translation < 20 mm and those (n = 10) with UIV translation ≥ 20 mm at the final follow-up. Correlations between UIV translation and radiographic or pulmonary function parameters were analyzed.RESULTSPatients with ≥ 20 mm UIV translation at the final follow-up had a significantly larger preoperative UIV translation than that in the patients with < 20 mm UIV translation at follow-up. The former group also had a significantly lower correction rate of the MT curve, higher chest cage ratio, and lower radiographic shoulder height (p = 0.01, 0.005, and 0.025, respectively) at the final follow-up. The Scoliosis Research Society (SRS)–30 Questionnaire scores were equivalent between the two groups. Correlation analysis showed that the following parameters were significantly associated with UIV translation: MT curve correction rate (r = -0.481, p = 0.015), chest cage ratio (r = 0.673, p < 0.001), and percent-predicted forced expiratory volume in 1 second (r = -0.455, p = 0.033).CONCLUSIONSThe UIV translation should be considered an important factor that influences postoperative results. In MT AIS patients whose preoperative upper end vertebra (UEV) is distant from the C7PL, the UIV should be selected above the UEV to prevent large UIV translation at the postoperative follow-up.

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