The aim of this study is to compare patients undergoing one level anterior cervical discectomy without fusion versus anterior cervical discectomy with fusion. The study included forty-eight patients operated at either C5-C6 level or at the C6-C7 level: a group of anterior cervical microdiscectomy without fusion performed at one level on 24 consecutive patients was matched to a second group of 24 patients with single-level of anterior cervical discectomy with fusion, based on level, age and sex. The kinematic analysis included the range of motion, intervertebral angulations, anteroposterior translation and disc height assessed for the cervical functional spinal units at the operated level and adjacent levels. At the operated level the range of motion and the translation were minimal in the anterior cervical discectomy without fusion group, both for the C5-C6 and C6-C7 levels, and absent in the cervical discectomy with fusion group. The superior adjacent levels range of motion and the translation were greater in the ACDF group compared with the ACD group. The clinical results of anterior cervical microdiscectomy without fusion and anterior cervical discectomy with fusion were comparable. In cervical microdiscectomy without fusion the elastic fibrous intradiscal scar at the operated level allows a small degree of mobility and the adjacent cervical levels are not overstressed. No need for anterior cervical discectomy with fusion to trait a single level cervical disc herniation than in selected cases.