What is the likely diagnosis for a 70-year-old male experiencing leg pain worsened by back extension but improved with flexion?

The clinical presentation described aligns well with lumbar spinal stenosis. In this condition, narrowing of the spinal canal can lead to compression of the spinal nerves, particularly during certain movements. Patients often experience leg pain or claudication that is exacerbated by back extension, such as standing or walking, as these positions further narrow the canal and increase pressure on the nerves. Conversely, flexion of the spine, such as leaning forward or sitting, tends to relieve symptoms by creating more space in the canal and reducing nerve compression.

In older adults, lumbar spinal stenosis is a common diagnosis, particularly due to age-related degenerative changes in the spine. These changes can include hypertrophy of the ligamentum flavum, degenerative disc disease, and facet joint osteoarthritis, all contributing to the narrowing of the spinal canal.

Other potential diagnoses, such as a herniated disc, typically present with radicular symptoms like sharp pain along a dermatomal distribution, which may not necessarily improve with spinal flexion. Spinal fractures often present with acute pain and may be associated with a history of trauma or osteoporosis, but do not typically present with the specific pattern of pain relief seen in this scenario. Degenerative disc disease can cause lower back pain, but it does