Which assessment is specifically recommended before surgery for patients with severe spine deformities due to ankylosing spondylitis?

• A. EKG
• B. Liver function tests
• C. Bone density scan
• D. Pulmonary function testing

Answer: (D)

Severe spine deformities from ankylosing spondylitis create a restrictive ventilatory pattern because the chest wall becomes stiff and the kyphosis limits rib cage expansion. This reduces vital capacity and total lung capacity, raising the risk of postoperative respiratory complications and making anesthesia management more challenging. Preoperative pulmonary function testing provides objective data on how well the lungs can ventilate and gas exchange, helping clinicians predict anesthesia risks, plan airway and ventilation strategies, and arrange appropriate postoperative respiratory support. While other tests like EKG, liver function, or bone density can be useful in general preop assessment, they do not specifically quantify the respiratory limitations caused by the spinal deformity.