Do abdominal cutouts in thoracolumbosacral orthoses increase pulmonary function?

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.

(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?

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).

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).

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.