I had spine surgery and woke up with a surprising new symptom: numbness along the front and sides of both thighs. The surgeon told me not to worry about it. She said it would be gone in less than a week and it was. What was it caused by?
You may have had a common post-operative condition called meralgia paresthetica. It's caused by pressure on the lateral femoral cutaneous nerve (LFCN). If you had surgery from the back you were likely face down during the operation. The surgeon may have used a special table or frame to support your body. Four posts support the chest and pelvis. The hips are bent slightly and the abdomen is unsupported. It's important to avoid pressure on the belly. Pressure on major blood vessels in the abdomen could cause bleeding. However, in this position pressure on the LFCN can cause temporary impairment. Numbness or altered sensation can last anywhere from one week to two months. Once the pressure is removed the nerve recovers completely.