A 60-year-old man is unable to walk more than 100 yards without experiencing severe pain in his left leg; the pain is relieved by resting for 5–10 minutes. He is told that the arteries of his leg are becoming occluded with fatty material and is advised to have the sympathetic nerves serving that body region severed. Explain how such surgery might help to relieve this man's problem.

Verified step by step guidance

1. Understand the patient's condition: The man is experiencing intermittent claudication, which is pain caused by insufficient blood flow to the leg muscles during walking due to arterial occlusion by fatty deposits (atherosclerosis).
2. Recognize the role of the sympathetic nervous system: Sympathetic nerves regulate vasoconstriction, which narrows blood vessels and reduces blood flow. In this case, sympathetic stimulation may worsen the reduced blood supply by causing further vasoconstriction in the already narrowed arteries.
3. Explain the effect of severing sympathetic nerves: Cutting these nerves (sympathectomy) reduces sympathetic-induced vasoconstriction, leading to vasodilation (widening of blood vessels). This can improve blood flow to the affected leg muscles despite the arterial occlusion.
4. Connect improved blood flow to symptom relief: Increased blood flow helps deliver more oxygen and nutrients to the leg muscles during activity, reducing ischemic pain and allowing the patient to walk longer distances without severe pain.
5. Summarize the therapeutic goal: The surgery aims to alleviate symptoms by enhancing blood supply through vasodilation, compensating partially for the arterial blockage and improving the patient's quality of life.

Key Concepts

Peripheral Arterial Disease and Claudication

Peripheral arterial disease (PAD) involves narrowing or blockage of leg arteries due to fatty deposits, reducing blood flow. Claudication is the pain caused by muscle ischemia during walking, relieved by rest. Understanding this condition explains the patient's symptoms of leg pain after walking short distances.

Role of Sympathetic Nervous System in Vascular Tone

The sympathetic nervous system controls blood vessel constriction by releasing neurotransmitters that cause vasoconstriction. In PAD, excessive sympathetic activity can worsen ischemia by further narrowing arteries. Severing sympathetic nerves reduces vasoconstriction, promoting vasodilation and improving blood flow.

Sympathectomy as a Therapeutic Intervention

Sympathectomy involves cutting sympathetic nerves to decrease vasoconstriction and increase blood supply to affected limbs. This can relieve ischemic pain by improving oxygen delivery to muscles. Although it does not remove arterial blockages, it helps manage symptoms in patients with PAD.