A 65-year-old male presents with a 6-month history of bilateral leg pain, numbness, and weakness that worsens with prolonged standing and walking. He reports that his symptoms are relieved by sitting down or leaning forward, such as when pushing a shopping cart. Peripheral pulses are palpable and symmetrical. Which of the following is the most likely diagnosis?

Explanation

The patient's symptoms of bilateral leg pain, numbness, and weakness that worsen with standing/walking and are relieved by sitting or leaning forward (flexion) are classic for neurogenic claudication, which is characteristic of lumbar spinal stenosis. The 'shopping cart sign' (relief with leaning forward) is a hallmark. Peripheral arterial disease (vascular claudication) would typically present with calf pain on exertion, relieved by rest, but not specifically by spinal flexion, and often associated with diminished peripheral pulses. Diabetic neuropathy causes sensory and motor deficits, but typically has a 'stocking-glove' distribution and is not primarily exacerbated by standing/walking and relieved by flexion in this manner. Trochanteric bursitis causes lateral hip pain, often worse with lying on the affected side or direct palpation, not bilateral leg symptoms relieved by spinal flexion.