We analyzed postoperative hematoma in cervical expansive laminoplasty, and examined 15 cases by ultrasound. Eight cases showed hematoma in the sutured area of cervical posterior muscles. All cases showed absorption of hematoma in 3 to 4 weeks. Ultrasound confirmed the presence, size, and depth of the hematoma. These results indicated that the start time of exercise to cervical posterior muscles was 3 to 4 weeks postoperatively.
