Safety and efficacy of lateral mass screws at C7 in the treatment of cervical degenerative disease

Abstract

Background:To evaluate the safety and efficacy of lateral mass screws at C7 in the treatment of cervical degenerative disease.Methods:Patients with cervical degenerative disease who underwent posterior cervical fusion and fixation from 2009 to 2015 were included in the study. All complications were captured. Postoperative X-ray and computed tomography (CT) confirmed fusion at 6 and 12 months after surgery. X-ray and CT confirmed screw loosening, misplacement, pull-out, breakage, or rod breakage.Results:Seventy-two patients underwent cervical laminectomy and fixation with lateral mass screws at C7 and had at least 1 year follow-up. One patient had C3 screw pull-out; revision was not required. There were no complications related to the C7 screws, and all were in the lateral mass.Conclusions:Lateral mass screws are as safe and effective as pedicle screws at C7 in long-segment posterior cervical fixation, have a lower rate of perioperative complications than pedicle screws, and are technically easier to place.

Lateral Mass Screws Versus Pedicle Screws at C7 - Reoperation Rates for Adjacent Segment Disease (Operative ASD) and Nonunions (Operative Nonunions) in Posterior Cervical Fusions

“…There are no similar studies to this in the literature. Several of the studies were comparative 11,27 with LMS and CPS at all cervical levels of the spine or noncomparative [21][22][23][24][25] with either all LMS screws or all CPS or a combination of both. 26…”

“…23,24 One with nonunion rates for LMS screws of 3%, 23 while another with all LMS found no evidence of screw pullout at C7 and no incidence of nonunions. 24 There are a few noncomparative studies using only CPS reporting symptomatic nonunions in PCF. 22,25 Kotil et al, in 2011, 22 found no nonunions using CPS between C3 and C7, while Nagashima et al, 25 in a more heterogenous study of LMS and CPS, found implant failures, such as screw breakage or loosening indicating pseudarthrosis, with pedicle screws at C7 occurred in 49.0% of the total number of patients, but all implant failures were asymptomatic and not associated with any clinical event by chance.…”

“…In our study, we found that an operative ASD incidence rate was 1.15% for LMS at C7 and 2.99% for CPS at C7. Again, although reoperations for nonunions with LMS or CPS at C7 in PCFs have been highlighted in a few studies, 11,[22][23][24][25][26][27] none have had a direct comparison. None of the studies have CPS only at C7, with LMS at other levels.…”

“…How these biomechanical studies translate to clinical outcomes to the superiority of one technique over another (LMS vs . CPS) is still unclear, with limited studies comparing both techniques 11,21–27…”

“…[18][19][20] How these biomechanical studies translate to clinical outcomes to the superiority of one technique over another (LMS vs. CPS) is still unclear, with limited studies comparing both techniques. 11,[21][22][23][24][25][26][27] Recent studies have shown no difference in reoperation rates for adjacent segment disease and for nonunions stopping posterior fusions at C7 versus crossing the cervical thoracic junction. [28][29][30] The corollary to this is: Does the type of screws used at C7 make a difference in outcomes?…”