Thigh numbness after surgery for perianal abscess may be caused by nerve damage during surgery or thrombosis of the lower limbs after lying in bed, which can be improved by drugs or surgery. 1. Nerve damage: During perianal abscess surgery, the nerve may be damaged due to improper operation, resulting in numbness of the thigh, you can take nerve-nourishing drugs such as vitamin B12 or methylcobalamin to promote the recovery of damaged nerves. 2. Thrombosis: After surgery, prolonged bed rest may cause the formation of thrombus in the lower limbs, and the impaired blood circulation will affect the nutritional supply of the nerves and numbness. The thrombus can be removed through surgical intervention under the guidance of the doctor to promote the improvement of symptoms. Therefore, when there is numbness in the thighs after perianal abscess surgery, it is recommended to go to the hospital in time for examination, to clarify the cause of the disease, and to receive standardized treatment under the guidance of the doctor. Drugs need to be used under the guidance of a doctor, drug allergy is prohibited.