Physical therapist will be consulted one day before and after the operation (OP) day. On the day before the OP day, they focus on education, including how to get up from bed and stand up from a chair. Five rehabilitation exercises are also demonstrated: 1) ankle flexion and extension, 2) knee flexion and extension, 3) hip joint abduction and adduction, 4) hip joint flexion and extension, and 5) drawing-in maneuver. The participants will be required to repeat each component to confirm that they can do it correctly. Each exercise is suggested to be done 10 times per day following MI-TLIF, and the number will be recorded 3 days (pre-OP day, post-OP day, and post-OP day 2).

This scale evaluates subject's physical function. The range is 0 to 1. Higher values represent a better outcome.

This scale evaluates subject's pain intensity. "0" indicates no pain and "10" indicates the worst possible pain.

This scale evaluates subject's health-related quality of life. We will record the subscales: physical component summary (PCS) and mental component summary (MCS). Higher values represent a better outcome.

It is a dynamic measure of balance. A 100 cm yardstick will be horizontally set on the wall with the acromion height. The patient will be asked to make a fit and reach forward as far as possible without moving his/her feet. It will be measured twice and the better outcome will be recorded.

It is used to evaluate the lower limb function and strength relating to the daily activities. The patient starts with a sitting position, and need to repeat stand-to-sit movements. He/She will be encouraged to move safely as soon as possible in 30 minutes. Higher number indicates better function.