Introduction: MR images done for the evaluation Cervical Spondylosis (CS) depict only static factors causing cord compression. The dynamic factors can be assessed when MRI is done in Extension or Flexion along with routine Neutral images. This study was done to elucidate factors associated with increase in compression levels & degree of compression in dynamic MRI.
Methods: A prospective study of Thirty four patients, (20 –radiculopathy;14–myelopathy) who were subjected to dynamic MRI after ruling out instability. Mid sagital T2W-MR Images were presented to 4 board certified neurosurgeons, who analyzed the compression levels (thecal sac compression anterior or posterior or combined – based on our modification of Muhle et al grading for spinal stenosis) and the management plan based on Extension and Neutral images. Inter-rater correlation coefficient (ICC), intramedullary signal change, curvature of spine, spinal cord occupancy rate, Stage of degeneration was analyzed.
Results: Thirty four patients (M:F = 25:9,age 46.6±11.4) were analyzed. Patients with myelopathy had increased number of mean compression levels in extension (4.1 ± 0.6, P – 0.001) than in neutral. There was significant worsening in the grade of compression at C2-3, C3-4, C4-5 (P <0.05) in myelopathy group along with increase in the number of compression levels. Older patients had increase in the number of compression levels (P<0.001). The mean number of proposed decompression levels among two of the four investigators had significantly changed. (Investigator I – P =0.025, investigator II- P = 0.036). In extension, ICC also increased from 0 .39 in neutral to 0.66 in myelopathy group and from 0.83 in neutral to 0.86 in non myelopathy group).
Conclusions: Older age & myelopathy were factors that are associated with increase in the severity of compression as well as the number of compressed levels in extension MRI which necessitated a change in surgical approach in >40% of patients with myelopathy.
Patient Care: This study has come up with two factors, age and myelopathy which are associated with increase in degree as well as number of compression levels.When these factors are present, patients can be subjected to dynamic MR imaging.
The number of proposed decompression levels can be decided after addressing the dynamic factors.As both the static and dynamic factors are assessed in decision making, the pathological process can be better addressed surgically.
Learning Objectives: At the end of this session, delegates will be able to better understand:
1.The influence of static and dynamic factors in the pathogenesis of cervical spondylotic myelopathy
2.They would know which factors increase the number and severity of compression in different neck postures
3.Understand the potential for change in the management plan based on dynamic MRI studies.