Not being able to walk normally twelve days after minimally invasive surgery for lumbar synostosis at the age of eighty is generally not normal. Generally speaking, after the lumbar surgery 2~3 days will be able to walk normally, can not walk normally may be the surgical wound healing is not good, surgical complications such as muscle injury, double lower limb sensory disorders and so on. 1. Poor healing of surgical wounds: 80 years old patients belong to the elderly, the metabolism may slow down, resulting in the healing of surgical wounds slower than young people, surgical wounds do not heal completely may lead to the inability to walk normally. 2. Muscle damage: the improper operation of the surgeon during the surgery may cause muscle damage, which will prolong the healing time and cause muscle pain, and also lead to the inability to walk on the ground normally. 3. Sensory impairment of both lower limbs: If the nerves are damaged during the surgery, there may be symptoms of sensory impairment of both lower limbs, and weakness and numbness of both lower limbs may occur, which may also lead to the inability to walk normally even after twelve days of the surgery. It is recommended to go to the hospital in time to find out the cause of the inability to walk normally, and carry out treatment under the guidance of the doctor.