Biomechanical Effects of Thoracolumbosacral Orthosis Design Features on 3D Correction in Adolescent Idiopathic Scoliosis: A Comprehensive Multicenter Study

Finite element study on three osteotomy methods for treating thoracolumbar osteoporotic fracture vertebral collapse complicated with neurological dysfunction

BACKGROUND

Surgical methods for patients with osteoporotic fracture vertebral collapse complicated with neurological dysfunction are still a topic of debate. We designed an improved osteotomy for the treatment of osteoporotic compression fracture patients with neurological dysfunction. Compared with traditional osteotomy methods such as pedicle subtraction osteotomy (PSO) and bone-disc-bone osteotomy (BDBO), the osteotomy range is reduced. Therefore, we use a finite element method to analyze the biomechanical conditions of these three osteotomy methods and provide a mechanical theoretical basis for the surgical treatment of these three osteotomy methods.

METHODS

Based on the CT scan of a patient with L1 osteoporotic fracture vertebral collapse and neurological dysfunction, the finite element model was constructed by importing Mimics software, and three different osteotomy models were established. The forces and displacements of internal fixation device, T1-L5 whole segment, T10 vertebral body, and T10/11 intervertebral disc were recorded under different working conditions.

RESULTS

The displacement levels of internal fixation device, T1-L5 spine, T10 vertebral body, and T10/11 intervertebral disc in the modified osteotomy group were between BDBO group and PSO group. The stress in BDBO group was concentrated in titanium mesh and its maximum stress was much higher than that in PSO group and modified osteotomy group. The mechanical distribution of T10/11 intervertebral disc showed that the maximum stress distribution of the three osteotomy methods was similar.

CONCLUSION

The relatively simple modified osteotomy has certain advantages in stress and displacement. In contrast, the stability of BDBO group was poor, especially in the lumbar intervertebral disc and lumbar body. For this type of osteotomy patients, it is recommended to avoid postoperative flexion so as not to increase the load.

Automated design of nighttime braces for adolescent idiopathic scoliosis with global shape optimization using a patient-specific finite element model

Adolescent idiopathic scoliosis is a complex three-dimensional deformity of the spine, the moderate forms of which require treatment with an orthopedic brace. Existing brace design approaches rely mainly on empirical manual processes, vary considerably depending on the training and expertise of the orthotist, and do not always guarantee biomechanical effectiveness. To address these issues, we propose a new automated design method for creating bespoke nighttime braces requiring virtually no user input in the process. From standard biplanar radiographs and a surface topography torso scan, a personalized finite element model of the patient is created to simulate bracing and the resulting spine growth over the treatment period. Then, the topography of an automatically generated brace is modified and simulated over hundreds of iterations by a clinically driven optimization algorithm aiming to improve brace immediate and long-term effectiveness while respecting safety thresholds. This method was clinically tested on 17 patients prospectively recruited. The optimized braces showed a highly effective immediate correction of the thoracic and lumbar curves (70% and 90% respectively), with no modifications needed to fit the braces onto the patients. In addition, the simulated lumbar lordosis and thoracic apical rotation were improved by 5° ± 3° and 2° ± 3° respectively. Our approach distinguishes from traditional brace design as it relies solely on biomechanically validated models of the patient's digital twin and a design strategy that is entirely abstracted from empirical knowledge. It provides clinicians with an efficient way to create effective braces without relying on lengthy manual processes and variable orthotist expertise to ensure a proper correction of scoliosis.

Automated extraction of biplanar stereo-radiographic image measurements: Mizzou 3D SPinE

PURPOSE

Although several studies have reported on the application of biplanar stereo-radiographic technology in pediatric clinical practice, few have performed large-scale analyses. The manual extraction of these types of data is time-consuming, which often precludes physicians and scientists from effectively utilizing these valuable measurements. To fill the critical gap between clinical assessments and large-scale evidence-based research, we have addressed one of the primary hurdles in using data derived from these types of imaging modalities in pediatric clinical practice by developing an application to automatically transcribe and aggregate three-dimensional measurements in a manner that facilitates statistical analyses.

METHODS

Mizzou 3D SPinE was developed using R software; the application, instructions, and process were beta tested with four separate testers. We compared 1309 manually compiled three-dimensional deformity measurements derived from thirty-five biplanar three-dimensional reconstructions (image sets) from ten pediatric patients to those derived from Mizzou 3D SPinE. We assessed the difference between manually entered values and extracted values using a Fisher's exact test.

RESULTS

Mizzou 3D SPinE significantly reduced the duration of data entry (95.8%) while retaining 100% accuracy. Manually compiled data resulted in an error rate of 1.58%, however, the magnitude of errors ranged from 5.97 to 2681.82% significantly increased the transcription accuracy (p value < 0.0001) while also significantly reducing transcription time (0.33 vs. 8.08 min).

CONCLUSION

Mizzou 3D SPinE is an essential component in improving evidence-based patient care by allowing clinicians and scientists to quickly compile three-dimensional data at regular intervals in an automated, efficient manner without transcription errors.

The efficacy of 3D personalized insoles in moderate adolescent idiopathic scoliosis: a randomized controlled trial

Background

Bracing and exercise methods were used in scoliosis rehabilitation and proven effective. There was little evidence about the efficacy of insoles on scoliosis.

Objective

This study aimed to investigate the effects of 3D personalized insoles on curve magnitude, postural stability, and quality of life (QOL) in moderate adolescent idiopathic scoliosis (AIS) patients.

Methods

Thirty-six volunteers with adolescent idiopathic scoliosis, who had moderate curves (20°-45°), were randomly divided into the experimental and control groups. The control group received traditional rehabilitation with bracing and exercises, and the experimental group received the insole interventions in addition to traditional rehabilitation. The outcome measures were Cobb angle, angle of trunk rotation (ATR), postural stability, and quality of life (Scoliosis Research Society-22 questionnaire). Measurements were conducted at baseline examination, two months and six months.

Results

After two and six months of treatment, the Cobb angle and ATR in both groups were significantly decreased as compared with the baseline (p < 0.05), but no significant group difference in Cobb angle and ATR was found in the study (p > 0.05). There was a significant difference in the sagittal balance index at six months compared to the control group (p < 0.05), and a significant difference in the coronal balance index was observed at six months compared to baseline in the experimental group (p < 0.05). Quality of life did not change in either group (p > 0.05).

Conclusion

Combining bracing with exercise in patients with moderate AIS is effective. 3D personalized insoles cannot reduce the Cobb angle and angle of trunk rotation of patients with moderate AIS but might have the potential to improve postural stability.

Improvement of Adolescent Idiopathic Scoliosis Primary Correction by Brace Design Optimization

(1) Background: Primary in-brace correction has been shown to be related to conservative adolescent idiopathic scoliosis (AIS) treatment outcome. The purpose of the study was to evaluate TLSO brace design changes over eight years regarding primary Cobb correction and de-rotation of the (major) curve. (2) Methods: This retrospective analysis included AIS patients treated with a full-time TLSO-brace in a single Orthopedic University hospital in 2012–2014 and 2017–2019. Brace design changes resulted from an evolutionary process, from a 3-point bending to a 3D TLSO. The brace parameters (presence of an anterior shoulder pad, posterior high-thoracic pad, thoracic space, and angle of the lumbar and thoracic pressure points) were analyzed regarding the primary (major) Cobb angle and apex rotation correction with a multivariate analysis. (3) Results: A total of 74 (63 female) patients were included in the study. The Cobb angle primary correction was significantly improved over the timeframe. The primary correction was significantly influenced by all design parameters and partially by its interactions with (curve specific) different effects on the Cobb correction and apex de-rotation. (4) Conclusions: Knowledge about the effects of brace design parameters on the curve’s angle and rotation correction enables improvements in individualized brace design and the brace optimization process.