Five patients with fixed upper airway obstruction were evaluated with maximum expiratory and inspiratory flow-volume curves before and after surgical repair of the obstruction. Flow-volume curves improved notably in two patients, improved moderately in two, and deteriorated in one. Symptoms and direct visualization of the obstruction before and after surgery correlated well with the changes seen in the flow-volume curves. None of the peak expiratory flow rates returned to predicted values after surgery, indicating at least some residual obstruction in all patients. It is concluded that flow-volume curves are an accurate, noninvasive technique for the diagnosis and subsequent assessment of therapy in patients with fixed upper airway obstruction.
(Arch Intern Med 137:309-312, 1977)