Orthofix Cervical-Stim 2505CE, Instruction Manual

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For purposes of device evaluation, all films were scanned into a central database
and reviewed by two independent, blinded orthopedic surgeons and a blinded,
independent radiologist following completion of the entire study. Films were
viewed and scored using a common protocol. All films at each time point were
evaluated for amount of radiolucency, bony bridging and degree of motion as
evidenced on the flexion/extension cervical spine films. A software program
was used to calculate motion. Results obtained in this fashion were reviewed
and verified by the reviewing orthopedic surgeons. The radiologist’s diagnosis
was considered definitive in the case of a disagreement between the two
orthopedic surgeons.
Effectiveness Results
Of the 323 subjects who were randomized and received surgery, 240 were
evaluable for the effectiveness analysis (Cervical-Stim treatment group, n=122;
control group, n=118). Subjects were deemed unevaluable for the following
reasons: non-existent or non-readable x-rays, subject non-compliance,
protocol violations (inclusion criteria), graft collapse, broken internal hardware,
early study exits due to minor adverse experiences, and one suicide attempt.
The success or failure of these subjects is not known. These unavailable data
could positively or negatively affect the overall success of the study. In order
to assess the impact of the missing data, sensitivity analyses were performed.
These included last observation carried forward and all missing data imputed
as non-fusion. Both of these analyses showed that the results at six months
were still statistically significantly different in favor of the Cervical-Stim group.
In addition, the baseline demographic data from the evaluable population was
compared to the demographic data of the missing subjects. The results of this
analysis indicated there were no significant differences between the evaluable
subjects and the non-evaluable subjects in 14 study variables including key
demographics and clinical parameters.
Primary Effectiveness Endpoint
The primary effectiveness endpoint was evidence of radiographic fusion at the
six month time point postoperative. At the six month time point, 102 of the
122 evaluable subjects (84%) in the Cervical-Stim treatment group were
judged to be fused versus 81 of the 118 evaluable subjects (69%) in the control
group (p=0.0065).
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These data show that for patients undergoing cervical fusion surgery, patients
treated adjunctively with the Cervical-Stim experienced an increase in the
frequency of radiographic fusion at six months when compared to the control group.
Treatment Group
Control
Cervical-Stim
Number of Subjects
118
122
Number of Subjects
Fused
81
102
Fusion Rate (%)
68.64
83.61
Comparison of Radiographic Fusion Outcomes at Six Months
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