Which of the following conditions is NOT considered a strong risk factor for DVT?

Prolonged bed rest is indeed recognized as a risk factor for deep vein thrombosis (DVT), especially since immobility leads to stasis of blood flow in the veins, particularly in the lower extremities. DVT occurs when a blood clot forms in the deep veins, often as a result of conditions that lead to either stasis (like long periods of inactivity) or injury to the vascular endothelium.

In the context of the other options, surgery is a significant risk factor for DVT due to various factors, including the degree of immobility during recovery and the potential for vascular injury during the procedure. Trauma can also elevate the risk, as it may directly injure veins or lead to a hypercoagulable state. Spinal cord injury is associated with increased risk of DVT due to the lack of mobility and altered physiology as a result of the injury.

Therefore, prolonged bed rest, contrary to the assertion that it is not a strong risk factor, is a well-established contributor to the development of DVT.