Positional Hemodynamic Instability in a Patient With Pectus Excavatum Undergoing Lumbar Discectomy.

Pectus excavatum (PE) is the most common congenital chest wall deformity, accounting for 90% of cases, and may predispose patients to hemodynamic compromise due to cardiac compression. Such events during spinal surgery, however, are rarely reported. In the widely used genupectoral prone position for spine surgeries, the patient lies prone with the torso supported and the legs flexed, thereby reducing abdominal compression, improving venous drainage, and reducing bleeding. However, the support provided by the thorax in this position may cause significant mediastinal compression in the presence of pectus excavatum, potentially resulting in hemodynamic instability. In this case, a 65-year-old man experienced hemodynamic collapse more than ten minutes after positioning, following further optimization of thoracic support for lumbar discectomy. The procedure was halted, and the patient was repositioned supine, which promptly resolved the instability. Postoperative evaluation revealed a Type 2 myocardial infarction (NSTEMI) without significant coronary artery stenosis on delayed angiography, consistent with demand ischemia secondary to mechanically induced reduction in cardiac output. Given the risk of spinal epidural hematoma, the decision to delay anticoagulation is the most instructive point for spine surgeons and should remain central to this discussion. Although the clinical course was ultimately benign, neurosurgeons and anesthesiologists should remain aware of the potential complications associated with the knee-chest position in patients with significant pectus excavatum. A thorough physical examination is therefore essential before positioning a patient, even for standard procedures.