Four months after the cervical spine surgery, the heavy back may be related to the local bruising and muscle tissue adhesion. 1. Local bruising: when cervical spine surgery results in a heavy back, the surgery is usually performed through the posterior cervical spine, which may result in abnormal back sensation due to chronic localized blood seepage and failure to absorb the blood in a timely manner after the surgery. 2. Tissue adhesion: Due to the slow recovery after surgery, adhesion of local muscles and tissues at the surgery site may affect the normal function of the nervous system, resulting in similar symptoms, which is also one of the common causes. If you experience back heaviness after cervical spine surgery, it is recommended that you seek medical attention in time, and under the guidance of your doctor, you can apply physical therapy methods such as hot compresses, ultrashort waves or infrared rays, to promote local blood circulation and the absorption of inflammatory exudation, and to alleviate the uncomfortable symptoms.