Implant Density at the Apex Is More Important Than Overall Implant Density for 3D Correction in Thoracic Adolescent Idiopathic Scoliosis Using Rod Derotation and En Bloc Vertebral Derotation Technique

Spine ◽  
2018 ◽  
Vol 43 (11) ◽  
pp. E639-E647 ◽  
Author(s):  
Alexandre Delikaris ◽  
Xiaoyu Wang ◽  
Laure Boyer ◽  
A. Noelle Larson ◽  
Charles G.T. Ledonio ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
En Bloc ◽  
Implant Density

scholarly journals Correction objectives have higher impact than screw pattern and density on the optimal 3D correction of thoracic AIS: a biomechanical study

2021 ◽  
Author(s):  
Luigi La Barbera ◽  
A. Noelle Larson ◽  
Carl-Eric Aubin
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Biomechanical Study ◽  
Patient Specific ◽  
Low Density ◽  
En Bloc ◽  
Level Of Evidence ◽  
Biomechanical Models ◽  
Computer Based ◽  
Implant Density

Abstract Study design Assessment of screw pattern, implant density (ID), and optimization of 3D correction through computer-based biomechanical models. Objective To investigate how screw pattern and ID affect intraoperative 3D correction of thoracic curves in adolescent idiopathic scoliosis, and how different correction objectives impact the optimal screw pattern. Summary of background data Screw pattern, ID, correction objectives and surgical strategies for posterior fusion of AIS are highly variable among experienced surgeons. The “optimal” instrumentation remains not well defined. Methods 10 patient-specific multibody models of representative adolescent idiopathic scoliosis Lenke 1A cases were built and used to compare alternative virtual correction surgeries. Five screw patterns and IDs (average: 1.6 screws/instrumented level, range: 1.2–2) were simulated, considering concave rod rotation, en bloc derotation, and compression/distraction as primary correction maneuvers. 3D correction descriptors were quantified in the coronal, sagittal and transverse planes. An objective function weighting the contribution of intraoperative 3D correction and mobility allowed rating of the outcomes of the virtual surgeries. Based on surgeon-dependent correction objectives, the optimal result among the simulated constructs was identified. Results Low-density (ID ≤ 1.4) constructs provided equivalent 3D correction compared to higher (ID ≥ 1.8) densities (average differences ranging between 2° and 3°). The optimal screw pattern varied from case to case, falling within the low-density screw category in 14% of considered scenarios, 73% in the mid-density (1.4 < ID < 1.8) and 13% in the high-density. The optimal screw pattern was unique in five cases; multiple optima were found in other cases depending on the considered correction objectives. Conclusions Low-density screw patterns provided equivalent intraoperative 3D correction to higher-density patterns. Simulated surgeon’s choice of correction objectives had the greatest impact on the selection of the optimal construct for 3D correction, while screw density and ID had a limited impact. Level of evidence N/A.

scholarly journals ADOLESCENT IDIOPATHIC SCOLIOSIS: EVALUATION ON THE EFFECT OF SCREW DENSITY IN THE CORRECTION

2016 ◽  
Vol 15 (1) ◽  
pp. 17-21
Author(s):  
Enguer Beraldo Garcia ◽  
Liliane Faria Garcia ◽  
Enguer Beraldo Garcia Jr ◽  
Roberto Garcia Gonçalves ◽  
Saulo Terror Giesbrecht ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Medical Records ◽  
Transpedicular Fixation ◽  
Correction Rate ◽  
Screw Density ◽  
The Difference ◽  
Implant Density ◽  
Biostatistical Analysis ◽  
Main Curve

ABSTRACT Objective: The objective was to investigate implant density or the number of screws correlated with the correction of the main curve in patients undergoing surgery for adolescent idiopathic scoliosis (AIS). Methods: We evaluated 112 medical records: 33 patients with screw density of up to 50%, and 79 patients with a density of 100%; all patients underwent surgical correction by posterior approach with transpedicular fixation. Results: In the group of patients with screw density of up to 50% the residual Cobb median was 10°; in the group with 100% density, the median was 7°. Conclusion: Biostatistical analysis showed that the group with up to 50% of screw density presented correction rate of 82.1% and the group with 100% density had correction of about 86.8%. It is therefore concluded that the difference is statistically significant in favor of the fixation with 100% density (p =0.010).

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 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 Radiological outcomes of the selective spinal fusion for lenke type 5C adolescent idiopathic scoliosis

2021 ◽  
Vol 13 (1) ◽  
pp. 6-9
Author(s):  
Ghanshyam Kakadiya ◽  
Kalpesh Saindane ◽  
Viraj Gandbhir ◽  
Yogesh Soni, ◽  
Kushal Gohil ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Spinal Instrumentation ◽  
Pedicle Screws ◽  
P Value ◽  
Coronal Balance ◽  
Angle Correction ◽  
The Mean ◽  
Implant Density

Objective: To determine the short term radiological outcomes of Lenke type 5C adolescent idiopathic scoliosis in terms of Cobb angle correction and coronal balance after selective posterior segmental spinal instrumentation with pedicle screws. Methods: This retrospective cohort study was conducted in the department of Orthopaedic at tertiary care public hospital of Mumbai, India. The medical records of patients from 17th April 2015 to 29th October 2019 who underwent a selective spinal fusion with pedicle screws for Lenke type-5C adolescent idiopathic scoliosis were reviewed. Preoperative radiographs were evaluated for Cobb angle of the lumbar or thoracolumbar curve as well as a sagittal and lumbar modifier on anteroposterior and lateral standing films. The curve correction, implant density, number of segment fused and coronal balance was assessed on postoperative radiographs. The pre and postoperative comparison of important study variables was done and P-value was calculated with the help of the chi-square test. P-value <0.05 was considered statistically significant. Results: The total number of patients was 34. Majority (94.1%, n=32) were females while only 2(5.9%) were males. The mean age at the time of operation was 14.35±2.19 years (range 8 to 19 years). Mean pre-operative and post-operative Cobb angles were 61.790±13.120 (range 400 to 850) and 10.550±8.710 (range 00 to 300) respectively (P-value 0.00). The mean percentage of curve correction and percentage of fulcrum flexibility was 83.35±13.07 % (range 55% to 100%) and 59.56%±15.07 (range 28.57% to 84.60%) respectively (P value 0.469). Mean implant density and fusion mass was 66.03±7.94% (range 53 to 79%) and 10.32±2.8 (range 7 to 15%) segments respectively. The coronal balance was achieved in all patients. No major complication was noted. Conclusion: Near normal Cobb angle correction and coronal balance was achieved in all patients of Lenke type 5C adolescent idiopathic scoliosis treated with posterior segmental spinal instrumentation utilizing pedicle screws.

scholarly journals “Higher Pedicle Screw Density Does Not Result in Improved Curve Correction in Lenke 2 Adolescent Idiopathic Scoliosis”

2021 ◽  
Author(s):  
Timothy 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 Female, 9 male) 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

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