Hemilaminectomy Approach Resection For Spinal Dumbbell-shaped Tumors

ObjectiveThe dumbbell-shaped tumors describes spinal tumors that acquire an hourglass shape in the course of growth as they encounter an anatomic barrier such as the dura mater,a nerve-root foramen,or other bony elements.Surgical resection is the optimal choice for treating spinal dumbbell-shaped tumors,but the reports of using hemilaminectomy for resecting tumors are rare,fewer has been seen using the anterior lateral hemilaminectomy approach.The goal of this study is to investigate the surgical technique of the hemilaminectomy for the resection of spinal dumbbell-shaped tumors and provide advices on clinical operations.MethodsRetrospective analysis the 26 adult patients' clinical data in Department of Neurosurgery,Cancer Hospital Chinese Academy of Medical Sciences from March 2013 to May 2018.All patients underwent CT and MRI inspections to assess the relationship between the tumor and surrounding tissues.The type of tumors and suitable surgical approach are determined by Eden and Toyama classification.All patients use the hemilaminectomy to resect the tumors.The patients' clinical and imaging data were collected to analysis surgical method,operation time,pathology and hospitalization days.All patients were told regular reexamination when discharged.On the last follow-up,patients' symptom and imaging data will be assessed to determine the surgical effectiveness.Spine instability will be called if the spine curvature changed more the 15 degrees.Results26 patients,including 12 males and 14 females,average age 37(11 to 65 years old).All have spine compression symptoms,including limb numbness in 13 patients and pain in 11 patients.2 patients felt chest distress because of thoracic occupation.Course of diseases range from 1 month to 10 years(average 17.5 month).11 patients with tumor occupying one vertebral body,13 in two vertebral bodies and 2 in three.15 patients with tumors located in the cervical spine,3 in the cervicothoracic spine,6 in the thoracic spine and 2 in the lumbar spine.The maximum diameter of tumors range from 3.2 to 11 cm.According to Eden classification,4 were classified as type 2,21 as type 3,1 as type 4.Hemilaminectomy was used in all patients to resect the tumor.Including posterior median hemilaminectomy approach in 13 patients,anterior lateral hemilaminectomy approach in 12 patients and combined anterior and posterior approach in 1 patient.Gross total resection was achieved in all but 1 patient in this group.Operation time range from 70-330 minutes(average 190 minutes),6 patients received blood transfusion during operations(range from 1200-2400ml).The pathological diagnoses included 16 schwannomas,3 neurofibromas,2 chordomas,2 sarcomas,2 never root cysts and 1 meningioma.All patients were followed up with a period of 4 to 60 months(average 37 months),the patients' symptoms were significantly relieved without obviously spine instability.ConclusionsHemilaminectomy can achieved satisfactory gross total resection rate in spinal dumbbell-shaped tumors,despite the locations and sizes.The giant tumor extended beyond cervical spinal canal could also be resected using anterior lateral hemilaminectomy approach.Compare to traditional laminectomy,hemilaminectomy has less trauma and little impact on the spine stability,thus avoiding laminoplasty or spine inner fixation.The vertebral artery protection is very important during the resection of cervical dumbbell tumors.The tumors' originated nerve root should also be carefully protected.When handling nerve root with tumor,the tumor should be resected as complete as possible to prevent recurrence.