Inclusion Criteria:  From 2006 to 2018, the patients admitted to the orthopedic department of our hospital for posterior cervical open-door expansive spinal canal laminoplasty with one side muscle-ligament complex reserved.Complete preoperative and postoperative diagnosis and treatment data of our hospital were available, and the follow-up time was ≥2 years.  Exclusion Criteria:  Patients with incomplete preoperative and postoperative diagnosis and treatment data or less than 2 years of follow-up