Contribution of dynamic cervical MRI to surgical planning for degenerative cervical myelopathy: Revision rate and clinical outcomes at 5 years’ postoperative

Abstract

IntroductionCervical MRI is the gold standard for surgical planning of degenerative cervical myelopathy; however, the symptomatic postoperative recurrence rate is high in the medium and long terms (9.1% to 10.7%) and may bring into question the quality of the preoperative surgical plan. The objective of this study was to evaluate cervical spinal stenosis and intramedullary hyperintensity with dynamic cervical MRI to determine the recurrence rate and clinical improvement in a cohort of patients who had dynamic cervical MRI incorporated into their surgical plan. MethodsThis was a prospective, single-center study. Upon enrolment and at each follow-up visit, patients completed the mJOA score, NDI, cervical pain on visual analog scale (VAS) and radicular pain on VAS. Every enrolled patient underwent dynamic cervical MRI (in neutral, flexion and extension positions). Five levels were measured in the three positions, resulting in 915 levels for analysis. ResultsSixty-one patients were included. Eighty-four levels had an intramedullary hyperintensity in neutral position, 93 in extension and 112 in flexion. The mean sagittal diameter varied the most at C4-C5, going from 7.13mm (SD 2.32) on average in neutral to 6.30mm (SD 2.22) in extension and 8.29mm (SD 2.10) in flexion, a variation of –12% and +16%, respectively. A Mühle grade≥2 was found in 134 levels in neutral position versus 189 in extension and 110 in flexion. None of the patients had worse neurological symptoms following the dynamic cervical MRI. The mean postoperative follow-up was 4.4 years (SD 0.88). Two patients (3.1%) required surgical revision because the implants had shifted. One patient developed symptomatic adjacent segment disease. ConclusionPreoperative surgical planning that incorporates dynamic cervical MRI before the surgical treatment of degenerative cervical myelopathy appears to be a safe and reliable method and one that helps reduce symptoms in the long term. Level of evidenceIV.