Exploration of Contributory Factors to an Unpleasant Bracing Experience of Adolescent Idiopathic Scoliosis Patients a Quantitative and Qualitative Research

BACKGROUND

To obtain a better understanding of the wearing habits and preferences of Adolescent Idiopathic Scoliosis (AIS) patients undergoing rigid brace treatment, we examine what factors contribute to patients' perceived discomfort during the treatment.

METHODS

Seventeen AIS patients treated with a rigid brace were recruited. We asked them to complete a questionnaire and participate in an interview study. Finally, we measure the interface corrective force and perceived discomfort with the participants for different positions and assess the correlation.

RESULTS

Our survey reveals that participants scored the lowest in the domains of environmental factors, psycho-spiritual factors, satisfaction, and self-image. Appearance anxiety, physical and psychological discomfort and inconvenience were the three most frequently mentioned problems in the interviews on participants' daily bracing experiences. A significant, moderately positive relationship between corrective force and discomfort level was found only when participants were lying on their left side, but not in any of the other positions. No significant correlation between treatment length and perceived discomfort was found.

CONCLUSIONS

Future work should focus on reducing the psychological burden and the inconvenience of wearing a brace, rather than on reducing physical discomfort resulting from the corrective force.

A study of the sensitivity of biomechanical models of the spine for scoliosis brace design

BACKGROUND AND OBJECTIVE

The development of biomechanical models of the torso and the spine opens the door to computational solutions for the design of braces for adolescent idiopathic scoliosis. However, the design of such biomechanical models faces several unknowns, such as the correct identification of relevant mechanical elements, or the required accuracy of model parameters. The objective of this study was to design a methodology for the identification of the aforementioned elements, with the purpose of creating personalized models suited for patient-specific brace design and the definition of parameter estimation criteria.

METHODS

We have developed a comprehensive model of the torso, including spine, ribcage and soft tissue, and we have developed computational tools for the analysis of the model parameters. With these tools, we perform an analysis of the model under typical loading conditions of scoliosis braces.

RESULTS

We present a complete sensitivity analysis of the models mechanical parameters and a comparison between a reference healthy subject and a subject suffering from scoliosis. Furthermore, we make a direct connection between error bounds on the deformation and tolerances for parameter estimation, which can guide the personalization of the model.

CONCLUSIONS

Not surprisingly, the stiffness parameters that govern the lateral deformation of the spine in the frontal plane are some of the most relevant parameters, and require careful modeling. More surprisingly, their relevance is on par with the correct parameterization of the soft tissue of the torso. For scoliosis patients, but not for healthy subjects, we observe that the axial rotation of the spine also requires careful modeling.

Pressure Sensor System for Customized Scoliosis Braces

Hard-shell thoracolumbar sacral orthoses (TLSOs) are used for treating idiopathic scoliosis, a deformation of the spine with a sideways curvature. The pressure required inside the TLSO for ideal corrective results remains unclear. Retrofitting TLSOs with commercially available pressure measurement systems is expensive and can only be performed in a laboratory. The aim of this study was to develop a cost-effective but accurate pressure sensor system for TLSOs. The sensor was built from a piezoresistive polymer, placed between two closed-cell foam liners, and evaluated with a material testing machine. Because foams are energy absorbers, the pressure-conductance curve was affected by hysteresis. The sensor was calibrated on a force plate with the transitions from loading to unloading used to establish the calibration curve. The root mean square error was 12% on average within the required pressure range of 0.01–0.13 MPa. The sensor reacted to the changing pressure during breathing and different activities when tested underneath a chest belt at different tensions. The peak pressure reached 0.135 MPa. The sensor was further tested inside the scoliosis brace during different activities. The measured pressure was 0.014–0.124 MPa. The results from this study enable cheaper and mobile systems to be used for clinical studies on the comfort and pressure of braces during daily activities.