Comments regarding “In-brace alteration of pulmonary functions in adolescents wearing a brace for idiopathic scoliosis” by Yagci et al. (2019)

I would like to thank the authors for elaborating on such an important topic and introducing it into Prosthetics and Orthotics International. However, I have spotted a number of methodological issues as well as literature-based evidence that challenge the findings by Yagci et al. (2019).

Scoliosis is a three-dimensional deformity that leads to alteration in spinal alignment in transverse and frontal planes as well as the sagittal plane, which results in a loss of the normal kyphosis and/or lordosis curves. ¹ Subsequently, the thoracic cage twists and compresses causing a restrictive lung disease as well as a decrease in lung volume and function. As such, hypoxemia, pulmonary hypertension, and heart failure may occur. Thus, morbidity and mortality rates are high in scoliotic patients with pulmonary problems. ¹

It is our opinion that conclusions drawn by Yagci et al. (2019), suggesting that bracing may compromise pulmonary function, are questionable. This is particularly the case because, taking into account that pulmonary function is expected to decrease in scoliotic patients regardless of brace wearing, the study should have considered recruiting a control group of participants to whom an intervention was not introduced as well as increasing the follow-up period.

In addition, the relation between each of the three dimensional deformities associated with scoliosis and pulmonary function was assessed using a computer tomography scan and it was found that the kyphosis (sagittal diameter) was the only variable correlated positively with lung function. ² However, the sagittal plane deformity was not mentioned in the Yagci et al. (2019) article, which may have been a major contributor to the results found by Yagci et al. (2019).

More importantly, the authors failed to choose a suitable brace design (which was shown in a figure) for the management of a scoliosis deformity. In particular, the chosen design has a posterior trim-line (at the inferior angle of the scapula) that is lower than the anterior trim-line (just below the clavicle), thus creating a posterior fulcrum around which the spine will be shifted in a hypokyphotic posture (lordotic). Such posture may increase the deformity and cause more restrictions on the pulmonary functions. ²

In addition, the use of bilateral pads under the clavicles (sub-clavicular pads) has been proven to restrict trunk elongation and thorax de-rotation and thus deterioration of scoliosis. ³ Finally, Refsum et al. concluded that a total contact and tightly fitted spinal orthosis (like the one used by Yagci et al. (2019)) could compress the abdominal viscera and subsequently restrict normal movement of the diaphragm, which in turn negatively affects pulmonary function. In turn, a non-total contact spinal orthosis (such as the Cheneau brace) has been proven to enhance pulmonary function and to allow for specialized respiratory physiotherapy program. ³