A 61-year-old man with back pain and numbness has pain that improves when bending forward. What is the most likely diagnosis?

The symptom of back pain that improves when bending forward is characteristic of spinal stenosis. This condition involves a narrowing of the spinal canal, which can put pressure on the spinal cord and nerve roots. When a person bends forward, it can create more space within the spinal canal, thereby alleviating the pressure and reducing pain.

In the case of spinal stenosis, patients often describe relief when leaning forward, such as when walking with a shopping cart or sitting, which is specifically due to the reduction in pressure on the affected nerves. This is a key distinguishing feature from other conditions.

Herniated discs typically cause pain that worsens with certain movements, usually related to activities that extend the spine, rather than bending it forward. Osteoarthritis can cause back pain but does not specifically correlate with symptoms improving in this manner. Sciatica refers to pain that follows the distribution of the sciatic nerve, often due to a herniated disc or other issues affecting the nerve, but again, it would not typically provide relief through forward bending.

Therefore, the clinical presentation makes spinal stenosis the most likely diagnosis for this patient.