C7 distal fixation anchor and its influence on sagittal profile in posterior cervical fusion; a retrospective analysis of 44 cases

Abstract

Study designRetrospective. PurposeIn multilevel posterior cervical fusion, whether to stop distal fixation at C7 or T1, remains a matter of debate. We aimed to assess clinical feasibility of C7 as distal fixation point and sought to compare complication rates and radiological outcome between lateral mass screws and pedicle screws at C7. Overview of literatureCurrent literature remains inconclusive regarding need for thoracic extension of instrumentation in multilevel posterior cervical fusion. MethodsWe did a retrospective review of 44 consecutive patients who underwent posterior instrumented cervical decompression and fusion for degenerative cervical myelopathy with C7 as distal fixation point, and a minimum follow-up period of two years. We had two groups of patients based on C7 instrumentation. Group 1Lateral mass screw fixation. Group 2Pedicle screw fixation. Primary outcomePost-operative clinico-radiological evaluation of whole study population Secondary outcome: Comparison of complication rates and radiological outcome between groups 1 and 2. ResultsMean age was 58.06 ± 14.4 years with average follow-up duration of 35.4 ± 4.5 months. There were 18 patients in Group 1 and 26 patients in Group 2. Mean pre-operative mJOA score was 10.51 and post-operative mJOA score was 15.74 with mean recovery rate (RR) 69.82%, of which 30 patients (70.23%) had good recovery and 14 patients (29.77%) had fair recovery at final follow up. The two groups didn't show any significant difference in complication rates and outcome. ConclusionC7 as distal fixation anchor is safe and effective in maintaining cervical sagittal balance following multilevel posterior cervical fusion. C7 lateral mass screws are found to be equally efficacious as pedicle screws in preventing worsening of sagittal profile.