Orthofix Cervical-Stim User Manual

Orthofix Inc.
U.S.A. Edition - Physician
P/N 571355-0001 Rev C 3/2009
Printed in U.S.A.
Date of Printing: 3/ 2009
CS-0903(A)-PL-US © Orthofix Inc.

Manufactured by:

Orthofix Inc.

1720 Bray Central Drive

McKinney, Texas 75069

Tel [phone]

800-535-4492

Cervical Fusion System

U.S.A. EDITION

PH Y S I CI A N MA N U A L

Table of Contents

Cervical-Stim

®

Physician Manual

Device Description ........ .................................... ................... ....................... 1

Prescription Information ................................................. ............................. 2

Clinical Data Summary .................. .................................... ................... ...... 3

Data Analysis & Results ............ ....................................................... ............ 5

Effectiveness Results .................................................... ................................. 6

Secondary Effectiveness Endpoints ............................................ .................... 7

Safety ................................. ....................................................... .................. 8

Device Life .. ....................................................... ......................................... 8

Treatment Time ........................................................................................... 8

Charging/Recharging the Battery ................................................................... 9

Device Operation ...... .................................... ................... .......................... 10

Wearing the Device ............. ....................................................... ................ 11

Care and Cleaning ............ .................................... ................... ................... 12

Travel ..................................................... .................................................... 12

Storage ... .................................... ................... .................................... ........ 12

Disposal ......................................................... ................... .......................... 12

Service .................. ......................... ................... .................................... ....... 12

Visual and Audio Indicators ..... ..................................................................... 13

Equipment Classification and Symbol Description ......................................... 14

Warranty Information ............................... ................... ............................... 16

To learn more about Orthofix, please visit our website at www.orthofix.com.

Package Contents:
1- Cervical-Stim Cervical Fusion System
1- Literature Pack
1- Charging Unit #270215

THIS DEVICE IS NONSTERILE.
IT DOES NOT REQUIRE STERILIZATION.

1

Device Description

The Cervical-Stim®Cervical Fusion System is an external, low-level, Pulsed
Electromagnetic Field (PEMF) device. It is a single-piece device that is
lightweight, flexible and portable, allowing freedom of movement during
treatment. A Liquid Crystal Display (LCD) and audible alarm provide
information during treatment (e.g. operational status, treatment time remaining,
battery capacity, etc.). See “Visual and Audio Indicators” for more information.

Cervical-Stim Cervical Fusion System - Model 2505

The Cervical-Stim is comprised of a control unit and a treatment transducer.
The control unit contains a micro-processor that generates the Cervical-Stim
electrical signal. That signal is converted to a highly uniform, low-energy
magnetic field by the treatment transducer. When the device is centered over
the treatment area, the therapeutic PEMF signal is delivered directly to the
fusion site.

The Cervical-Stim is powered by a rechargeable lithium-ion battery pack.
The LCD and audible alarm will alert the patient when the battery is low and
needs to be recharged. See “Charging/Recharging the Battery” for more
information.

2

To ensure that the device is functioning properly, the Cervical-Stim constantly
monitors battery voltage and the electrical signal. If at any time during
treatment the device stops functioning properly, the LCD will display an
appropriate symbol or error code. See “Visual and Audio Indicators” for
more information.

To stop treatment prior to the end of the daily treatment session, simply press
the On/Off button. To resume treatment, press the On/Off button again.
The LCD will display the remaining treatment time.

Prescription Information

Indication

The Cervical-Stim is a noninvasive, pulsed electromagnetic bone growth
stimulator indicated as an adjunct to cervical fusion surgery in patients at
high-risk for non-fusion.

Contraindications

There are no known contraindications for the Cervical-Stim as an adjunct to
cervical spine fusion surgery.

Warnings

• The Cervical-Stim may interfere with the operation of a cardiac pacemaker
or defibrillator. Consultation with the attending cardiologist is recommended.

• The Cervical-Stim should be removed prior to any imaging procedures
(e.g., CT scan, MRI, etc.).

Precautions

• The Cervical-Stim should not be used if there are mental or physical
conditions that may preclude compliance with physician or device
instructions.

• The Cervical-Stim has not been evaluated in treating patients with the
following conditions: osseous or ligamentous spinal trauma, spondylitis,
Paget’s disease, moderate to severe osteoporosis, metastatic cancer, renal
disease, rheumatoid arthritis, uncontrolled diabetes mellitus, patients prone
to vascular migraine headache, seizure, epilepsy, thyroid conditions or
neurological diseases.

• Animal teratological studies performed with this device did not show any
adverse effects in animals. However, the safety of this device for use on
patients who are pregnant or nursing has not been established.

Transducer

Control Unit

3 4

symptomatic radiculopathy. The purpose of the study was to evaluate the
safety and effectiveness of the PEMF Cervical-Stim device as an adjunct for
high-risk patients who undergo cervical fusion. All subjects underwent
anterior cervical discectomy and fusion using the Smith-Robinson technique
with the Atlantis Plate. Subjects were randomly assigned to either the control
group (standard treatment, n=160) or the treatment group (standard treatment
plus the Cervical-Stim, n=163). Standard treatment was at the physician's
discretion but typically included the standard hospital stay, use of a soft cervical
collar, appropriate medications and physical therapy.

Subjects who met the following inclusion and exclusion criteria were eligible
for participation in the study:

Inclusion Criteria

Adult male or female, 18-75 years old with radiographic evidence of
compressed cervical nerve root(s), symptomatic radiculopathy, pain of 5 or
greater on the Visual Analog Scale (VAS) and/or any muscle weakness and
primary cervical spinal fusion performed using the Smith-Robinson technique
with allograft bone and an anterior cervical plate. The fusion procedure must
have been either multi-level (>1 fusion level) or the subject was a smoker
(one pack/day or more) or both; and have a signed informed consent form.

Exclusion Criteria

Traumatic cervical injury, posterior approach or revision fusion, autograft
or bone substitute materials for graft source, history of vascular migraine
headache or prone to uncontrolled seizures or epilepsy (controlled or
uncontrolled) or any neurological diseases or injury; depressed immune
system, regional conditions (Spondylitis, Paget’s disease, rheumatoid arthritis),
infection (systemic or local) within 2 weeks prior to surgery, systemic
conditions (cancer, cardiac arrhythmia, thyroid disease, uncontrolled diabetes
mellitus, renal disease/dysfunction, chronic steroid use or other conditions that
may have affected bone metabolism), cardiac pacemakers, defibrillators, dorsal
column stimulators, hearing aids, cochlear prostheses and cranial stimulators,
subjects who were pregnant, nursing or had planned to become pregnant
within 12 months, subjects that had participated in other clinical studies within
the last 12 months, or had mental or physical conditions which may have
precluded compliance with physician instructions.

Evaluation and Follow-Up

Follow-up visits were to have been performed at months 1, 2, 3, 6 and 12
and annually thereafter until the last subject enrolled reached 12 months.

Device Usage

Subjects assigned to the treatment group (Cervical-Stim) were instructed
to wear the device for four hours per day for a minimum of three months
postoperative. Surgeons could, at their discretion, extend the Cervical-Stim
treatment up to six months postoperative.

Clinical Data Summary

Study Design

The Cervical-Stim clinical study was a controlled, randomized, parallel
group study of 323 high-risk (smokers, multi-level or both, and allograft) adult
subjects with radiographic evidence of compressed cervical nerve roots and

Adverse Events Reported at 6 Months by Treatment Group

Increased Neck Pain
S

houlder/Arm Pain
Re-Injury to Cervical Spine
Adjacent Level Pathology
Surgical Complications
LBP/Lumbar Pathology
Trauma/Injury(not cervical)
Numbness/Tingling
Headache/Migraine
Nonspecific/Unrelated Pain
Nausea
Dizziness/Vertigo
Rash/Discoloration
Rapid/Irregular Heartbeat
Shortness of Breath
Ringing in Ears
Neurologic Symptom/Stroke
Lump in Throat
Diagnosis of Diabetes
Diagnosis of Breast Cancer
Seizure
Death, Unrelated
Tenderness
Screw Broken
Graft Collapse
Carpal Tunnel Syndrome
Choking Sensation
Cardiac Symptoms
Nephrotic Syndrome
Suicide Attempt

TOTAL

Adverse Events

# (%) of

E

vents

1

0(14.9)
10(14.9)
10(14.9)

3

(4.5)

2(3.0)

8(11.9)

2(3.0)

6(8.9)

2(3.0)

2(3.0)

0

2(3.0)

0
0
0
0

1(1.5)

0
0
0
0

0
1(1.5)
1(1.5)
1(1.5)
2(3.0)
1(1.5)
1(1.5)
1(1.5)
1(1.5)

67

# (%)

1

of

P

atients

E

xperiencing
the Event

9

(5.6)
9(5.6)
8(5,0)
3

(1.9)
2(1.3)
8(5.0)
2(1.3)
6(3.8)
2(1.3)
2(1.3)

0

2(1.3)

0
0
0
0

1(0.6)

0
0
0
0

0
1(0.6)
1(0.6)
1(0.6)
2(1.3)
1(0.6)
1(0.6)
1(0.6)
1(0.6)

47

2

#*(%) of

E

vents

1

6(17.8)

16(17.8)

9(10.0)

8

(8.8)
7(7.7)
5(5.5)
5(5.5)
4(4.4)
4(4.4)
3(3.3)
2(2.2)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)
1(1.1)

0
0
0
0
0
0
0
0

90

# (%)

1

of

P

atients

E

xperiencing
the Event

1

5(9.2)

16(9.8)

9(5.5)
8

(4.9)
5(3.1)
5(3.1)
4(2.5)
4(2.5)
4(2.5)
3(1.8)
2(1.2)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)
1(0.6)

0
0
0
0
0
0
0
0

58

2

Control Group (n=160)

Cervical-Stim Group (n=163)

Adverse Events

1

% expressed as number of patients experiencing the event / total number of patients in the group

2

Some patients experienced multiple adverse events

*

There were several adverse events that were more frequently observed in the Cervical-Stim group than in the
control group. Given the types of events, it is unlikely that these adverse events are related to the treatment.

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).

6

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

1

. P-values of comparison tests between treatment groups using Student’s t-test for numerical

variables and Pearson x2test for categorical variables.

Data Analysis and Results

The primary effectiveness endpoint was the increase in frequency of cervical
fusion success by six months postoperatively as assessed by radiographic
evidence. Secondary endpoints were neurological function, VAS pain assessment
and Neck Disability Index. Safety was assessed by the frequency and severity
of adverse events.

Fusion was assessed by radiographs at each visit:
Radiographic fusion was defined as > 50% bony bridging on both the

superior and inferior graft interfaces between adjacent vertebral bodies
AND < 4° angulation (motion) between adjacent fused vertebrae on
flexion/extension lateral films AND absence of radiolucency.

Radiographic non-fusion was defined as < 50% bony bridging at either the

superior or inferior graft interface OR > 4° angulation (motion) between
adjacent fused vertebrae on flexion/extension lateral films OR presence
of radiolucency.

5

V

ariables

Age (years)

Mean
Range
SD

Gender

Female
Male

Race

Caucasian
African-American
Hispanic
Asian
Other

Smoking Status

Nonsmoking
Smoking

Number of

Subjects

(N = 323)

46.8

24 – 73

9.3

148(45.8%)
175 (54.2%)

301(93.2%)

17 ( 5.3%)

5 ( 1.6%)

0
0

159 (49.2%)
164 (50.8%)

Control

(n = 160)

46.7

26 – 72

9.2

75 (46.9%)
85 (53.1%)

150 (93.8%)

7 ( 4.4%)
3 ( 1.9%)

-

-

79 (49.4%)
81 (50.6%)

Cervical-Stim

(n = 163)

46.9

24-73

9.4

73 (44.8%)
90 (55.2%)

151 (92.6%)

10 ( 6.1%)

2 ( 1.2%)

-

-

80 (49.1%)
83 (50.9%)

P-value

1

0.846

0.706

0.703

0.958

Baseline Demographic Characteristics

Comparison of Radiographic Fusion Outcomes at Six Months

Demographic Data

The subjects in this study had a mean age of 46.8 years (range 24 to 73 years).
Of the 323 subjects, 148 (45.8%) were female and 175 (54.2%) were male.
Three hundred one (93.2%) were Caucasian, while 17 (5.3%) were African
American and 5 (1.6%) were Hispanic. One hundred fifty-nine (49.2%) were
nonsmokers and 164 (50.8%) were smokers.

8

Safety

The adverse events observed in this study are shown in the Adverse Events
Table presented in the Prescription Information section. At six months, the
numbers of subjects who experienced one or more adverse events is similar
in the two groups. A total of 14 severe events were reported in 13 subjects;
nine of the subjects were in the Cervical-Stim treatment group and five
subjects were in the control group. These events included experiences such
as increased pain, shortness of breath, dizziness, unrelated trauma and injury,
unrelated death, surgical complication and adjacent level pathology. For the
nine subjects in the Cervical-Stim treatment group, all severe adverse events
were, in the judgment of the investigators, definitely or probably unrelated to
the device.

Safety data obtained between the six month visit and the final contact with
each subject indicate that 57 adverse events were experienced by a total of
51 subjects between both groups. The number of subjects who experienced
one or more adverse events is similar in the two groups. None of the adverse
events reported between the six month visit and the final contact were severe
and are similar to those reported at six months.

Device Life

The Cervical-Stim can provide up to 270 consecutive (daily) treatments of four
hours each. The overall length of treatment will be determined by the physician
based on the patient and progress toward fusion.

Treatment Time

The Cervical-Stim should be worn for four hours per day. The device will
automatically turn off when four hours of treatment is reached in a 24-hour
day. The device may be turned off at any time by simply pressing the On/Off
button on the control panel.

The Cervical-Stim may be used at any time of day that is convenient for the
patient. It is lightweight and adjustable. And because the Cervical-Stim is
portable, treatment can be received while sitting, walking, reclining, sleeping,
etc. However, since each patient is unique, the overall activity level should be
based on your instructions.

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 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 (x2= 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).