Device Description
The Mobi-C® Cervical Disc Prosthesis (Mobi-C®)
is a single use device for cervical intervertebral disc replacement at
one level or two contiguous levels from C3 to C7 designed to
maintain/restore segmental motion and disc height. The components of
the Mobi-C® include a cobalt, chromium, molybdenum (CoCrMo
per ISO 5832-12) alloy superior spinal plate, an inferior CoCrMo
spinal plate, and an ultra-high molecular weight polyethylene (UHMWPE
per ISO 5834-2) mobile insert. The inner contact surfaces of the
superior and inferior spinal plates are spherical and flat,
respectively. This allows for fully congruent contact surfaces between
the spinal plates and mobile insert. The two lateral stops of the
inferior plate are designed to control and limit the mobility of the
mobile insert. The spinal plates, both superior and inferior, feature
two rows of teeth which are designed to aid in initial and long term
fixation and stability. The teeth are designed to sink into the bone
to facilitate endplate fixation and do not require any bone removal or
chiseling prior to insertion. A titanium (per ASTM F1580) and
hydroxyapatite (per ISO 13779) plasma spray coating is applied to the
bony interface surfaces of the superior and inferior spinal plates.
Indications for Use
The Mobi-C® Cervical Disc Prosthesis is indicated in
skeletally mature patients for reconstruction of the disc from C3-C7
following discectomy at one level or two contiguous levels for
intractable radiculopathy (arm pain and/or a neurological deficit)
with or without neck pain, or myelopathy due to abnormality localized
to the level of the disc space and at least one of the following
conditions confirmed by radiographic imaging (CT, MRI, X-rays):
herniated nucleus pulposus, spondylosis (defined by the presence of
osteophytes), and/or visible loss of disc height compared to adjacent
levels. The Mobi-C® Cervical Disc Prosthesis is implanted
using an anterior approach. Patients should have failed at least 6
weeks of conservative treatment or demonstrated progressive signs or
symptoms despite nonoperative treatment prior to implantation of the
Mobi-C® Cervical Disc Prosthesis.
Contraindications
The Mobi-C® Cervical Disc Prosthesis should not be
implanted in patients with the following conditions:
- Acute or chronic infection, systemic or at the operative
site;
- Known allergy or sensitivity to the implant materials
(cobalt, chromium, molybdenum, titanium, hydroxyapatite, or
polyethylene);
- Compromised vertebral bodies at the index
level due to previous trauma to the cervical spine or to significant
cervical anatomical deformity or disease (e.g., ankylosing
spondylitis, rheumatoid arthritis);
- Marked cervical
instability on resting lateral or flexion/extension radiographs
demonstrated by translation greater than 3.5mm, and/or > 11°
angular difference to that of either adjacent level;
- Osteoporosis or osteopenia defined as DEXA bone mineral density
T-score < -1.5;
- Severe facet joint disease or
degeneration.
Warnings
- Mobi-C® should only be used by surgeons who are
experienced with anterior cervical spinal procedures and have
undergone hands-on training in the use of this device. Only surgeons
who are familiar with the implant components, instruments,
procedure, clinical applications, biomechanics, adverse events, and
risks associated with the Mobi-C® should use this device.
A lack of adequate experience and/or training may lead to a higher
incidence of adverse events, including neurological
complications.
- Correct selection of the appropriate implant
size is extremely important to assure the placement and function of
the device. Information regarding proper implant size selection,
implant site preparation, and the use of the instrumentation before,
during, and after Mobi-C® surgery is provided in the
Mobi-C® Surgical Technique Manual and the
Mobi-C® Instrument System Instructions for Use. Users are
advised to read and understand the surgical technique manual and
instructions for use prior to surgery.
- Due to the proximity
of vascular and neurological structures to the implantation site,
there are risks of serious or fatal hemorrhage and risks of
neurological damage with the use of the device. Care must be taken
to identify and protect these structures.
- Heterotopic
Ossification (HO) is a potential complication associated with
artificial cervical discs and could lead to reduced cervical motion.
However, the presence of HO has not been correlated with adverse
clinical outcomes involving the Mobi-C® Cervical Disc
Prosthesis in the G050212 clinical trial.
Precautions
The safety and effectiveness of this device has not been established
in patients with the following conditions:
- Skeletally immature patients, pediatric or adolescent children
(<21 years old), or those over the age of 67;
- Prior
cervical spine surgery, including prior surgery at the index
level;
- More than two diseased or immobile cervical spine
levels requiring surgical intervention;
- Disc height less
than 3mm measured from the center of the disc in a neutral position
and disc height less than 20% of the anterior-posterior width of the
inferior vertebral body;
- Significant kyphotic deformity or
significant reversal of lordosis;
- Active malignancy;
- Paget’s disease, osteomalacia, or other metabolic bone
disease;
- Taking medications known to potentially interfere
with bone/soft tissue healing (e.g. steroids);
- Pregnancy;
- Diabetes mellitus requiring daily insulin
management;
- Clinically extreme obesity (class III) as defined
by the NIH Clinical Guidelines Body Mass Index (i.e. BMI
>40);
- Neck or arm pain of unknown etiology;
- Systemic disease including AIDS, HIV, and Hepatitis;
- Intractable radiculopathy or myelopathy due to pathology at more
than two levels and/or pathology not localized to the level of the
disc space;
- Prior fusion at an adjacent vertebral
level;
- Neck pain alone;
- Rheumatoid arthritis or
other autoimmune disease;
- Neuromuscular disorders such as
muscular dystrophy, spinal muscular atrophy, or amyotrophic lateral
sclerosis;
- Acute mental illness or substance abuse.
Pre-operative
- Patient selection is extremely important. In selecting
patients for total disc replacement, the following factors can be of
importance to the success of the procedure: the patient’s occupation
or activity level, prior injury or other ongoing illness,
alcoholism, or drug abuse; and certain degenerative diseases (e.g.,
degenerative scoliosis or ankylosing spondylitis) that may be so
advanced at the time of implantation that the expected useful life
of the device is substantially decreased.
- In order to
minimize the risk of periprosthetic vertebral fractures, surgeons
must consider all co-morbidities, past and present medications,
previous treatments, etc. A screening questionnaire for osteopenia
or osteoporosis, SCORE (Simple Calculated Osteoporosis Risk
Estimation), may be used to screen patients to determine if a DEXA
bone mineral density measurement is necessary. If DEXA is performed,
the patient should be excluded from receiving the device if the DEXA
bone density measured T score is < -1.5, as the patient may be
osteoporotic or osteopenic.
- The patient should be informed
of the potential adverse effects (risks/complications) contained in
the insert (see ADVERSE EVENTS).
- Preoperative planning may
be used to estimate the required implant size and to assure that the
appropriate range of sizes is available for surgery. The procedure
should not take place if the appropriate range of sizes will not be
available.
- Examine all instruments prior to surgery for wear
or damage. Instruments which have been used excessively may be more
likely to break. Replace any worn or damaged instruments.
Intra-operative
- Use aseptic technique when removing the Mobi-C® from the
innermost packaging. Carefully inspect each component and its
packaging for any signs of damage, including damage to the sterile
barrier. Do not use Mobi-C® implants if the packaging is
damaged or the implant shows signs of damage.
- Use care when
handling the Mobi-C® to ensure that it does not come in
contact with objects that could damage the implant. Damaged implants
are no longer functionally reliable. Visual inspection of the
prosthesis assembly is recommended prior to implanting the device.
If any part of the assembly appears damaged or not fully assembled,
do not use.
- To prevent unnecessary damage to the bearing
surfaces, ensure that tissue or other debris is not trapped within
the device.
- The Mobi-C® should not be used with
components or instruments of spinal systems from other
manufacturers. See the surgical technique for step by step
instructions.
- Surgical implants must never be re-used or
reimplanted. Even though the device appears undamaged, it may have
small defects and internal stress patterns that may lead to early
breakage.
- Perform a complete discectomy of the disc space
between the unci and up to the posterior ligament. Take care to
release the foramen bilaterally. It is important to remove all
anterior and posterior osteophytes on the superior and inferior
vertebral endplates. Liberally cover bleeding with bone wax. To
prevent weakening of the endplates, use of a burr is discouraged
during endplate preparation. Use the Caspar Retractor as needed to
maintain or modify distraction. Ensure proper alignment and
placement of device components as misalignment may cause excessive
wear and/or early failure of the device.
Post-operative
- Patients should be instructed in postoperative care procedures
and should be advised of the importance of adhering to these
procedures for successful treatment with the device including the
avoidance of heavy lifting, repetitive bending, and prolonged or
strenuous activity initially and for a period of weeks to months
depending on the individual patient’s progress and the stability and
functioning of the implant.
- Note to Physician: Although the
physician is the learned intermediary between the company and the
patient, the important medical information given in this document
should be conveyed to the patient.