A patient presents with worsening back pain that radiates to their legs while standing. What is the most likely diagnosis?

The symptoms described in the scenario align well with lumbar spinal stenosis. This condition is characterized by the narrowing of the spinal canal, which can put pressure on the spinal cord and the nerves that exit the spine. Patients often experience back pain that may radiate to the legs, particularly when they stand or walk. This symptom pattern occurs because standing and walking can increase the pressure on the affected nerves, leading to pain, numbness, or weakness in the legs—often described as claudication.

In patients with lumbar spinal stenosis, the discomfort usually improves with activities that relieve pressure on the spine, such as sitting or bending forward. In contrast, other conditions, such as a herniated disc, may present with more localized symptoms or pain that tends to worsen with certain positions rather than being relieved. Osteoarthritis generally leads to a more gradual onset of pain and stiffness, while a muscle strain is more associated with acute injuries and localized pain rather than the characteristic radicular symptoms seen with spinal stenosis. Thus, given the presentation of worsening back pain radiating to the legs while standing, lumbar spinal stenosis is the most fitting diagnosis.