Orthofix Cervical-Stim 2505CE, Instruction Manual

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7
Treatment Group
Control
Cervical-Stim
Number of Subjects
120
125
Number of Subjects Fused
104
116
Fusion Rate (%)
86.67
92.80
Overall Radiographic Fusion Fusion Outcomes at 12 Months
Note: The differences in long-term success rates between treatment groups is not statistically
significant per Pearson
x
2 test with the available sample size (
x
2 = 2.5136, p = 0.1129).
An additional analysis was performed to allow for the differences between
the Cervical-Stim treatment group and the control group with respect to
demographic characteristics (gender, age, diagnosis) and risk status (smoking,
multilevel). The overall fusion rate in the Cervical-Stim group remained
statistically significant after adjustment for each of these variables.
Long-term follow-up (12 months) showed no statistical difference between the
two groups with respect to fusion. One hundred sixteen of the 125 evaluable
subjects (92.8%) in the Cervical-Stim treatment group were judged to be fused
at the long-term final endpoint, while 104 of the 120 evaluable subjects
(86.7%) in the control group were judged to be fused.
Secondary Effectiveness Endpoints
Secondary endpoints evaluated changes in clinical symptoms. A “clinical success”
with regard to symptoms was defined as no worsening in neurological function,
an improvement in VAS pain assessment and no worsening in Neck Disability
Index. A “clinical failure” with regard to symptoms was defined as failure for
any one of these criteria. There was no statistically significant difference
between the two groups with respect to the percent of subjects considered
a “clinical success” at six months (p= 0.8456) or at 12 months (p= 0.1129).