Study of the pressures applied by a Chêneau brace for correction of adolescent idiopathic scoliosis

Predictive Parameters for Chêneau Brace Efficacy in Patients with Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective consecutive cohort study.

OBJECTIVE

For patients with mild to moderate adolescent idiopathic scoliosis (AIS), bracing is the standard therapy to prevent progression of deformity. Still, not all patients benefit from treatment in the same way. Therefore, predictive parameters are needed to determine if patients are likely to benefit from brace therapy.

METHODS

Fourty-five AIS patients treated with a Chêneau brace were evaluated retrospectively. Inclusion criteria were based on SRS-criteria. Whole spine X-rays were performed pre-brace, in-brace, and at least 6 months after termination of brace treatment. Gender, age, Risser's sign, vertebral rotation determined by Nash and Moe grading system, in-brace correction and in-brace time per day were parameters evaluated. Treatment success and failure groups were compared to determine possible predictive parameters for successful brace treatment.

RESULTS

Chêneau brace treatment was successful preventing curve progression in 69%. We found significant differences between success and failure group concerning age (14 ± .22 vs 12.4 ± .4; P < .001) and Risser's sign (1.71 ± .16 vs .5 ± .17; P < .001) at beginning of brace treatment. Most significantly, initial in-brace curve correction was correlated with successful outcome after brace treatment (r = .64 (P < .001)).

CONCLUSIONS

As one of few studies adhering to the criteria defined by the Scoliosis Research Society our study shows reliable predictive parameters for Chêneau brace treatment success in patients with AIS. Data shown in this paper will help to differentiate AIS patients who are likely to benefit from adequate bracing therapy from those who could rather benefit from early surgical treatment.

Infrared Thermography for Real-Time Assessment of the Effectiveness of Scoliosis Braces

This work proposes an innovative method, based on the use of low-cost infrared thermography (IRT) instrumentation, to assess in real time the effectiveness of scoliosis braces. Establishing the effectiveness of scoliosis braces means deciding whether the pressure exerted by the brace on the patient's back is adequate for the intended therapeutic purpose. Traditionally, the evaluation of brace effectiveness relies on empirical, qualitative assessments carried out by orthopedists during routine follow-up examinations. Hence, it heavily depends on the expertise of the orthopedists involved. In the state of the art, the only objective methods used to confirm orthopedists' opinions are based on the evaluation of how scoliosis progresses over time, often exposing people to ionizing radiation. To address these limitations, the method proposed in this work aims to provide a real-time, objective assessment of the effectiveness of scoliosis braces in a non-harmful way. This is achieved by exploiting the thermoelastic effect and correlating temperature changes on the patient's back with the mechanical pressure exerted by the braces. A system based on this method is implemented and then validated through an experimental study on 21 patients conducted at an accredited orthopedic center. The experimental results demonstrate a classification accuracy slightly below 70% in discriminating between adequate and inadequate pressure, which is an encouraging result for further advancement in view of the clinical use of such systems in orthopedic centers.

Are torso asymmetry and torso displacements in a computer brace model associated with initial in-brace correction in adolescent idiopathic scoliosis?

BACKGROUND

Lack of initial in-brace correction is strongly predictive for brace treatment failure in adolescent idiopathic scoliosis (AIS) patients. Computer-aided design (CAD) technology could be useful in quantifying the trunk in 3D and brace characteristics in order to further investigate the effect of brace modifications on initial in-brace correction and subsequently long-term brace treatment success. The purpose of this pilot study was to identify parameters obtained from 3D surface scans which influence the initial in-brace correction (IBC) in a Boston brace in patients with AIS.

METHODS

Twenty-five AIS patients receiving a CAD-based Boston brace were included in this pilot study consisting of 11 patients with Lenke classification type 1 and 14 with type 5 curves. The degree of torso asymmetry and segmental peak positive and negative torso displacements were analyzed with the use of patients' 3D surface scans and brace models for potential correlations with IBC.

RESULTS

The mean IBC of the major curve on AP view was 15.9% (SD = 9.1%) for the Lenke type 1 curves, and 20.1% (SD = 13.9%) for the type 5 curves. The degree of torso asymmetry was weakly correlated with patient's pre-brace major curve Cobb angle and negligible correlated with major curve IBC. Mostly weak or negligible correlations were observed between IBC and the twelve segmental peak displacements for both Lenke type 1 and 5 curves.

CONCLUSION

Based on the results of this pilot study, the degree of torso asymmetry and segmental peak torso displacements in the brace model alone are not clearly associated with IBC.

Actuator and Contact Force Modeling of an Active Soft Brace for Scoliosis

Scoliosis is an abnormality of the spinal curvature that severely affects the musculoskeletal, respiratory, and nervous systems. Conventionally, it is treated using rigid spinal braces. These braces are static, rigid, and passive in nature, and they (largely) limit the mobility of the spine, resulting in other spinal complexities. Moreover, these braces do not have precise control over how much force is being applied by them. Over-exertion of force may deteriorate the spinal condition. This article presents a novel active soft brace that allows mobility to the spine while applying controlled corrective forces that are regulated by varying the tensions in elastic bands using low-power light weight twisted string actuators (TSAs). This article focuses on the actuator and contact force modeling of the active soft brace (ASB). The actuator modeling is required to translate the twisting of string in terms of contraction of the string’s length, whereas the contact force modeling helps in estimating the net resultant force exerted by the band on the body using single point pressure/force sensors. The actuators (TSAs) are modeled as helix geometry and validated using a laser position sensor. The results showed that the model effectively tracked the position (contraction in length) with root mean square error (RMSE) of 1.7386 mm. The contact force is modeled using the belt and pulley contact model and validated by building a custom testbed. The actuator module is able to regulate the pressure in the range 0–6 Kpa, which is comparable to 0–8 Kpa pressure regulated in rigid braces. This makes it possible to verify and demonstrate the working principle of the proposed active soft brace.

TLSO with Graphene Sensors-An Application to Measurements of Corrective Forces in the Prototype of Intelligent Brace

This study presents a prototype of Intelligent Brace-the gold medal winner in the 68th edition of the International EUREKA 2019 Competition, in Valencia, Spain. It shows how to improve the effectiveness of a static orthopedic brace, with modern technology based on advanced electronic solutions. The research uses in-house-made thin-film graphene sensors, an electronic system with a microcontroller and derotating pads, a mobile application for Android system, and a remote database. The article presents a description of the real project, the system principle of operation, and the layout of the system elements in the orthosis. A prototype device was designed and built that was tested not only in laboratory conditions, but also during trials with the first patient. Approximately two months of data were collected and interpreted. The collected research results provided basic knowledge about the range of forces exerted by the brace on the patient's body, as well as the regularity of wearing the orthosis by the patient and compliance with the doctor's recommendations.

Active Soft Brace for Scoliotic Spine: A Finite Element Study to Evaluate in-Brace Correction

Scoliosis is a spinal disorder that is conventionally treated using rigid or soft braces. Computational methods such as finite element-based models are used to investigate the mechanics of the spine and the effect of braces. Most spinal braces are either passive, static, or rigid and do not allow mobility to the spine, resulting in muscle atrophy, skin deterioration and other spine complexities. Lack of control over the amount of force being exerted by braces on the human spine could have adverse effects. Therefore, developing an active soft brace which allows mobility to the spine while applying controlled corrective forces could be a promising solution. This study presents finite element analysis (FEA) of an active soft brace that applies corrective forces using elastic bands. The pressure exerted by the brace on the spine can be controlled by varying the tensions in the elastic bands. The elastic band tensions are controlled using low-power, lightweight, and twisted string actuators (TSAs). This study aims to demonstrate the immediate corrections induced by the soft active brace using a scoliotic spine finite element (FE) model. A FE model of the patient’s trunk was created and validated with in vitro study. The brace model was installed on the simulated trunk to evaluate in-brace correction in both sagittal and coronal planes. The brace was evaluated under various load cases by simulating the actuator action.

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.

The intra- and inter-observer reliability of interface pressure measurements of the Milwaukee brace in adolescents with hyperkyphosis

BACKGROUND

There is a lack of evidence in reliability of the modified sphygmomanometer to measure the brace-interface pad pressure in adolescents with Scheuermann's kyphosis (SK).

OBJECTIVES

To evaluate the intra- and inter-observer reliability of modified sphygmomanometer for measuring interface pad pressure in the Milwaukee brace.

METHODS

Two observers measured the pressure of the shoulder and kyphosis pads in Milwaukee brace on 33 adolescents with SK with an average age of 14.67 ± 1.72 years and Cobb angle 64.48∘± 7.53∘. All measurements were obtained in one day. The measurements were done in the inhalation and exhalation of tidal breathing during standing and sitting positions. The intraclass correlation coefficient (ICC), 95% confidence interval (CI), and linear mixed model ANOVA effects were calculated.

RESULTS

The intra-observer reliability varied from a good ICC of 0.81 (0.66-0.90) to an excellent of 0.97 (0.95-0.98). The inter-observer reliability also varied from a good ICC of 0.82 (0.67-0.91) to an excellent of 0.96 (0.93-0.98). The linear mixed model ANOVA analysis showed that the rater, position, and breathing had a significant effect on the pad pressure measurements.

CONCLUSIONS

The modified sphygmomanometer is a reliable tool to measure the pad pressure of the Milwaukee brace for adolescents with SK.

Analysis of the interface pressure exerted by the Chêneau brace in patients with double-curve adolescent idiopathic scoliosis

The Chêneau brace has proven its effectiveness in treating the adolescent idiopathic scoliosis patients. However, no studies reported on the analysis of interface pressure in double-curve adolescent idiopathic scoliosis patients. In this study, we evaluated the interface pressure of the Chêneau brace action in double-curve adolescent idiopathic scoliosis patient treatment. A total of 72 (60 girls and 12 boys) patients aged 10 years and above participated in the study. The F-Socket transducers (9811E) were used to evaluate the pressure on the right thoracic and left thoracolumbar curves between normal and maximum strap tension and variation in these interface pressures with other tasks. Each patient was asked to do nine different tasks corresponding to daily activities, and the interface pressures for each activity were recorded for both normal and maximum tension. The resultant mean peak pressure in double-curve adolescent idiopathic scoliosis was higher for right thoracic curves than left thoracolumbar curves in all tasks. The pressure significantly increased at the task of maximal inspiration ( p < 0.0001) for both types of curves for normal and maximum tension. The degrees of correction for the thoracic and thoracolumbar curves were 23.2% and 34.5%, respectively, after 6 months of brace use (23 h per day). Hence, we could not find any substantial correlation between mean peak pressure in the standing position and degree of scoliosis correction for two curves having r = 0.158, p = 0.356 and r =  –0.024, p = 0.889 values.

Optimizing the vertical position of the brace thoracic pad: Apical rib or apical vertebra?

INTRODUCTION

The vertical position of the thoracic pad is a subject of controversy in brace design. Traditional recommendations dictate a maximal force applied at the level of the apical rib, about 2 levels below the apical vertebra. We sought to evaluate the optimal vertical position of the brace thoracic pad using fulcrum bending radiographs.

HYPOTHESIS

A lateral force applied at the apical vertebra of a thoracic curve is more efficient at correcting coronal deformity than a force placed the apical rib.

PATIENTS AND METHODS

In this prospective study, we recruited patients presenting with adolescent idiopathic scoliosis (AIS) and Risser stage 0-2 over a period of 12 months. Patients with a history of spine or thoracic surgery were excluded. Two fulcrum bending radiographs were performed for each patient: one with the center of the fulcrum placed under the most lateral part of the apical rib and another with the fulcrum centered below the apical vertebra. Cobb angles were measured on each fulcrum radiograph and compared using a paired t test.

RESULTS

Fifty-two patients were included, with a mean age of 12.4 years and mean thoracic Cobb angle of 39.4˚. Placing a fulcrum under the apical vertebra reduced the Cobb angle to a mean of 11.5˚, which was significantly lower than a fulcrum placed under the apical rib (14.3˚, p=0.001). This corresponded to a 20% relative loss in the absolute correction angle when placing the fulcrum under the apical rib. The difference between the 2 Cobb angles was not significantly correlated to patient age (p=0.896) or curve apex (p=0.813).

DISCUSSION

This is the first clinical study addressing the vertical position of the thoracic pad in braces for AIS. A lateral force applied at the level of the apical vertebra was significantly more efficient at reducing thoracic curve deformities than one applied at the apical rib. Our results provide clinical support to finite element studies that refute traditional recommendations of brace design, advocating for a revision of these guidelines to optimize non-operative treatment of AIS.

LEVEL OF EVIDENCE

II, prospective comparative study.

Mechanical Testing of a Novel Fastening Device to Improve Scoliosis Bracing Biomechanics for Treating Adolescent Idiopathic Scoliosis

Velcro fastening straps are commonly used to secure a scoliosis brace around the upper body and apply corrective forces to the spine. However, strap loosening and tension loss have been reported that reduce spinal correction and treatment efficacy. A novel fastening device, or controlled tension unit (CTU), was designed to overcome these limitations. A scoliosis analog model (SAM) was used to biomechanically compare the CTU fasteners and posterior Velcro straps on a conventional brace (CB) as well as on a modified brace (MB) that included a dynamic cantilever apical pad section. Brace configurations tested were (1) CB with posterior Velcro straps, (2) CB with posterior CTU fasteners, (3) MB with posterior Velcro straps, and (4) MB with posterior CTU fasteners. MB configurations were tested with 0 N, 35.6 N, and 71.2 N CTU fasteners applied across the apical pad flap. Three-dimensional forces and moments were measured at both ends of the SAM. The CTU fasteners provided the same corrective spinal loads as Velcro straps when tensioned to the same level on the CB configuration and can be used as an alternative fastening system. Dynamically loading the apical flap increased the distractive forces applied to the spine without affecting tension in the fastening straps.

Global postural re-education in pediatric idiopathic scoliosis: a biomechanical modeling and analysis of curve reduction during active and assisted self-correction

Background

Global postural re-education (GPR) is a physiotherapy treatment approach for pediatric idiopathic scoliosis (IS), where the physiotherapist qualitatively assesses scoliotic curvature reduction potential (with a manual correction) and patient’s ability to self-correct (self-correction). To the author’s knowledge, there are no studies regarding GPR applied to IS, hence there is a need to better understand the biomechanics of GPR curve reduction postures. The objective was to biomechanically and quantitatively evaluate those two re-education corrections using a computer model combined with experimental testing.

Methods

Finite elements models of 16 patients with IS (10.5–15.4 years old, average Cobb angle of 33°) where built from surface scans and 3D radiographic reconstructions taken in normal standing and self-corrected postures. The forces applied with the therapist’s hands over the trunk during manual correction were recorded and used in the FEM to simulate this posture. Self-correction was simulated by moving the thoracic and lumbar apical vertebrae from their presenting position to their self-corrected position as seen on radiographs. A stiffness index was defined for each posture as the global force required to stay in the posture divided by the thoracic curve reduction (force/Cobb angle reduction).

Results

The average force applied by the therapist during manual correction was 31 N and resulted in a simulated average reduction of 26% (p < 0.05), while kyphosis slightly increased and lordosis remained unchanged. The actual self-correction reduced the thoracic curve by an average of 33% (p < 0.05), while the lumbar curve remained unchanged. The thoracic kyphosis and lumbar lordosis were reduced on average by 6° and 5° (p < 0.05). Self-correction simulations correlated with actual self-correction (r = 0.9).

Conclusions

This study allowed quantification of thoracic curve reducibility obtained by external forces applications as well as patient’s capacity to self-correct their posture, two corrections commonly used in the GPR approach.

Evaluation of the efficiency of the Chêneau brace on scoliosis deformity : A systematic review of the literature

BACKGROUND

Scoliosis is a three-dimensional deformity of the spine and rib cage. Depending on the severity of this disease, various kinds of treatment methods have been used and bracing is among the most common. One of the braces which has been used for subjects with scoliosis is the Chêneau brace. The aim of this review was to evaluate the efficiency of the Chêneau brace on the scoliosis curve progression and control based on the available literature.

METHOD

We conducted a Medline search via PubMed, Google Scholar, ISI Web of Sciences, Ebsco and Scopus. Keywords such as Chêneau brace, Chêneau light and CAD/CAM spinal brace were used in combination with scoliosis. The quality of the studies was evaluated by the Down and Black tool.

RESULTS

Based on the aforementioned keywords, 55 papers were found. Finally based on the mentioned criteria 14 papers were selected for final analysis. The quality of the studies varied between scores of 13 and 25 using the Down and Black tool. The results of the selected studies confirmed that a good scoliotic curve correction can be achieved with the Chêneau brace.

CONCLUSION

The Chêneau brace provides a 3-dimensional correction of the spinal deformity which not only influences the progression of scoliotic curve but also influences its natural history. It cannot be concluded that the Chêneau brace is superior to other available braces; however, it has been shown that this brace is effective to control the scoliotic curve progression especially in the lumbar and thoracolumbar regions.

Measurement of Milwaukee Brace Pad Pressure in Adolescent Round Back Deformity Treatment

Study Design

In this prospective study, we measured the pad pressures of the Milwaukee brace in adolescent hyperkyphosis treatment.

Purpose

We evaluated the skin-brace interface forces exerted by the main pads of the Milwaukee brace.

Overview of Literature

A fundamental factor associated with brace effectiveness in spinal deformity is pad force adjustment. However, few studies have evaluated the in-brace force magnitude and its effect on curve correction.

Methods

Interface forces at four pads of the Milwaukee brace were measured in 73 patients withround back deformity (mean age, 14.04±1.97 years [range, 10–18]; mean initial Cobb angle,67.70°±9.23° [range, 50°–86°]). We used a modified aneroid sphygmomanometer to measure the shoulder and kyphosis pad pressures. Each patient underwent measurement in the standing and sitting positions during inhalation/exhalation.

Results

The mean pad pressures were significantly higher in the standing than in thesitting position, and significantly higher pressures were observed during inhalation compared toexhalation (p=0.001).There were no statistically significant differences between right and left shoulder pad pressures (p>0.05); however, the pressure differences between the right and left kyphosis pads were statistically significant (p<0.05). In a comparison of corrective forces with bracing for less or more than 6 months, corrective force was larger with bracing for less than 6 months (p=0.02). In the standing position, there were no statistically significant correlations between pad pressures and kyphosis curve correction.

Conclusions

In the sitting position, there was a trend toward lower forces at the skin-brace interface; therefore, brace adjustment in the standing position may be useful and more effective. There was no significant correlation between the magnitude of the pad pressures and the degree of in-brace curve correction.

Do abdominal cutouts in thoracolumbosacral orthoses increase pulmonary function?

BACKGROUND

Thoracolumbosacral orthoses (TLSOs) are effective in their intended purpose of limiting spinal movement but tend to restrict rib cage and abdominal motion. Incorporating an abdominal cutout, allowing abdominal excursion, may reduce the restraint on abdominal expansion associated with inhalation and thereby reduce pulmonary compromise.

QUESTIONS/PURPOSES

(1) For healthy adults, does a TLSO restrict pulmonary function at rest and after exercise compared with no TLSO (control)? (2) At rest, is pulmonary function increased by adding an abdominal cutout to the TLSO (open) compared with a traditional closed TLSO (no abdominal cutout)? (3) Are those results similar after exercise?

METHODS

Twenty healthy adults wore a custom-molded TLSO with a reattachable abdominal cutout. Forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were recorded at rest and after exercise in three conditions: (1) no TLSO (control); (2) TLSO (closed); and (3) TLSO (open).

RESULTS

Wearing a TLSO (closed or open) reduced FVC and FEV1 similarly at rest (p < 0.001) and after exercise (p < 0.001) compared with controls. Adding an abdominal cutout (open) to the TLSO increased FVC at rest (95% confidence interval [CI], 3.79-4.76; p = 0.007) and postexercise (95% CI, 3.80-4.73; p = 0.025) compared with the closed TLSO, and FEV1 increased postexercise (95% CI, 3.01-3.76; p = 0.02) but not at rest (95% CI, 2.96-3.73; p = 0.053).

CONCLUSIONS

TLSOs restrict pulmonary function in healthy adults. An abdominal cutout in the TLSO increased pulmonary function, especially with activity, suggesting that cutouts should be considered when fabricating TLSOs for individuals with compromised breathing such as with neuromuscular disorders, scoliosis, or spine surgery.

Review of current technologies and methods supplementing brace treatment in adolescent idiopathic scoliosis

PURPOSE

To report on the current technologies and methods supplementing brace treatment in adolescent idiopathic scoliosis.

METHODS

A comprehensive literature review was performed to determine the effectiveness of bracing, to report on imaging techniques that can assist in the assessment of bracing, to understand the roles of the biomechanical treatment concepts on bracing and to address the importance of the quality of life of the brace wearers.

RESULTS

The effectiveness of bracing still remains controversial. Many technologies are still in development to improve the bracing process and quantify the effects of bracing. Imaging techniques with decreased or no radiation are promising in providing more frequent data on curve progression for patients. Computer-assisted design models have been used for both fitting and manufacturing the brace to patient contours. Ultrasound has been developed as a new means of diagnosing scoliosis and determining the effects of a brace on a patient's spine in real time. The brace treatment outcomes are correlated to the quantity and the quality of brace usage. Compliance monitors and force sensors have been developed to track the quality of brace usage. Improvements to brace wear also require consideration of patient quality of life. Surveys have been developed to describe the effects of family influence and self-image on bracing effectiveness of patient quality of life.

CONCLUSIONS

Bracing remains a highly qualitative process, relying on the empirical judgment of the physicians and orthotists, along with buy-in with the patient. The suggested improvements will help to push bracing into a more evidence-based practice.

Factors associated with the success of the Rigo System Chêneau brace in treating mild to moderate adolescent idiopathic scoliosis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is the most prevalent spine deformity within the pediatric population. Orthosis is the mainstay of conservative treatment for mild to moderate AIS. The Rigo System Chêneau (RSC) brace is a custom-made thoracolumbar sacral orthosis (TLSO) based on a three-dimensional correction concept. The purpose of this study was to identify factors that could predict the therapeutic success/failure of the RSC brace.

MATERIALS AND METHODS

A retrospective cohort study was performed on all consecutive patients according to the Scoliosis Research Society (SRS) criteria for the success of conservative treatment. Participants had a 2-year follow-up beyond the termination of brace treatment. All patients were treated with the RSC orthotic device.

RESULTS

Ninety-three patients met the inclusion criteria. At treatment onset, their average age was 12.9 years, average Cobb angle 31.97°, Risser score 1.07, and the mean angle of thoracic rotation (ATR) was 10.2°. The mean brace treatment period was 36 months. Treatment was successful in 83.8 % of these patients (n = 79). The average final Cobb angle was 28.97°, Risser score 4.88, and ATR 8.09°. The pre-treatment factors associated with the success of applying the RSC brace were a high Risser score [odds ratio (OR) = 2.97, 95 % confidence interval [CI] 1.18-7.44; p = 0.02), a low Cobb angle (OR = 0.92, 95 % CI 0.85-0.99; p = 0.02), and low ATR (OR = 0.86, 95 % CI 0.75-0.99; p = 0.04).

CONCLUSIONS

The treatment of mild to moderate AIS with the RSC brace provides excellent clinical results. Its added benefit is enabling a three-dimensional correction of a three-dimensional deformity. Pre-treatment high Risser score, low Cobb angles, and low ATRs are associated with treatment success.

LEVEL OF EVIDENCE

Retrospective analysis, Level III.

Analysis of the corrective forces exerted by a dynamic derotation brace (DDB)

BACKGROUND

Discrepancies exist in the current literature for bracing of spinal curvature conditions. This can be explained by the diversity of brace types, the different curve patterns and the various measurement methods and instruments.

OBJECTIVES

The aim of this study was the analysis of the corrective forces exerted by a dynamic derotation brace (DDB), at the skin-brace interface, altering the strap tension and body posture.

STUDY DESIGN

We analysed the direct forces exerted by a DDB's main pad, on 44 (38 girls, 6 boys) idiopathic scoliotic patients. Twenty-seven patients had a single right thoracic and 17 a single left or right thoracolumbar curve.

METHODS

We used the F-Socket 9801 pressure sensor and the MatScan Research BETA STAM 6.30 software, while patients adopted nine different postures. The patients were divided into three different groups: those who wore the brace for the first time, those who were changing their brace for a new one, and those who were having adjustments made to their existing brace.

RESULTS

These patients who were having adjustments made to their existing brace caused the highest mean exerted force. Changes in strap tension and body posture resulted in statistically significant alterations of the interface pressure and the forces exerted on the patient's body.

CONCLUSIONS

Tightening the brace's straps always produces a significant force increase, independent of the body posture and the curve type. Also there are some body postures which significantly modify the exerted force. The body posture of maximum inspiration for thoracolumbar curves and, additionally, prone and lying left for thoracic curves.