Hi, Numbness in the thigh can be caused by various factors, including nerve compression or injury. In your case, the numbness may be related to your L5 spondylolisthesis, which is a condition where one vertebra slips forward onto the one below it. This can cause pressure on the nerves that exit the spinal column at that level, leading to numbness, pain, and weakness in the affected area. Sitting for long periods can also contribute to numbness in the thigh, especially if you have poor posture or the chair you are sitting in is not ergonomically designed. This can cause compression of the nerves in the hip and thigh area, leading to numbness or tingling. It is important to maintain good posture and take frequent breaks from sitting to avoid numbness and other symptoms. You may also benefit from physical therapy or exercises to help alleviate your symptoms and improve your mobility. As for lifting, bending, and twisting, it is important to avoid activities that worsen your symptoms. Your healthcare provider or physical therapist can provide guidance on how to perform these activities safely and without causing further harm to your back and nerves. If you require a personalized response, kindly use the Ask A Doctor service and post a follow-up. Take care. Hope I have answered your question. Regards, Dr. Priyanka, General & Family Physician