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conditions, dictate the longevity of the implant. Notches,
scratches or bending of the implant during the course
of surgery may also contribute to early failure. Patients
should be fully informed of the risks of implant failure.
3. MIXING METALS CAN CAUSE CORROSION. There are
many forms of corrosion damage and several of these
occur on metals surgically implanted in humans. General
or uniform corrosion is present on all implanted metals
and alloys. The rate of corrosive attack on metal implant
devices is usually very low due to the presence of passive
surface films. Dissimilar metals in contact, such as titanium
and stainless steel, accelerate the corrosion process of
stainless steel and more rapid attack occurs. The presence
of corrosion often accelerates fatigue fracture of implants.
The amount of metal compounds released into the body
system will also increase. Internal fixation devices, such as
rods, hooks, etc., which come into contact with other metal
objects, must be made from like or compatible metals.
4.
PATIENT SELECTION. In selecting patients for internal
fixation devices, the following factors can be of extreme
importance to the eventual success of the procedure:
A. The patient’s weight. An overweight or obese patient
can produce loads on the device that can lead to failure
of the appliance and the operation.
B. The patient’s occupation or activity. If the patient is
involved in an occupation or activity that includes heavy
lifting, muscle strain, twisting, repetitive bending, stoop-
ing, running, substantial walking, or manual labor, he/she
should not return to these activities until the bone is
fully healed. Even with full healing, the patient may not
be able to return to these activities successfully.
C. A condition of senility, mental illness, alcoholism,
or drug abuse. These conditions, among others, may
cause the patient to ignore certain necessary limitations
and precautions in the use of the appliance, leading to
implant failure or other complications.
D. Certain degenerative diseases. In some cases, the pro-
gression of degenerative disease may be so advanced
at the time of implantation that it may substantially
decrease the expected useful life of the appliance. For
such cases, orthopaedic devices can only be considered
a delaying technique or temporary remedy.
E. Foreign body sensitivity. The surgeon is advised
that no preoperative test can completely exclude the
possibility of sensitivity or allergic reaction. Patients can
develop sensitivity or allergy after implants have been in
the body for a period of time.
F.
Smoking. Patients who smoke have been observed to
experience higher rates of pseudarthrosis following sur-
gical procedures where bone graft is used. Additionally,
smoking has been shown to cause diffuse degeneration
of intervertebral discs. Progressive degeneration of
adjacent segments caused by smoking can lead to late
clinical failure (recurring pain) even after successful
fusion and initial clinical improvement.
PRECAUTIONS
1. SURGICAL IMPLANTS MUST NEVER BE REUSED.
An explanted metal implant should never be reimplanted.
Even though the device appears undamaged, it may have
small defects and internal stress patterns which may lead
to early breakage. Reuse can compromise device perfor-
mance and patient safety. Reuse of single use devices can
also cause cross-contamination leading to patient infection.
2.
CORRECT HANDLING OF THE IMPLANT IS EXTREMELY
IMPORTANT. Contouring of metal implants should only
be done with proper equipment. The operating surgeon
should avoid any notching, scratching or reverse bending
of the devices when contouring. Alterations will produce
defects in surface finish and internal stresses which
may become the focal point for eventual breakage of the
implant. Bending of screws will significantly decrease the
fatigue life and may cause failure.
3.
CONSIDERATIONS FOR REMOVAL OF THE IMPLANT
AFTER HEALING. If the device is not removed after the
completion of its intended use, any of the following com-
plications may occur: (1) Corrosion, with localized tissue
reaction or pain; (2) Migration of implant position resulting
in injury; (3) Risk of additional injury from postoperative
trauma; (4) Bending, loosening, and/or breakage, which
could make removal impractical or difficult; (5) Pain,
discomfort, or abnormal sensations due to the presence
of the device; (6) Possible increased risk of infection; and
(7) Bone loss due to stress shielding. The surgeon should
carefully weigh the risks versus benefits when deciding
whether to remove the implant. Implant removal should be
followed by adequate postoperative management to avoid
refracture. If the patient is older and has a low activity
level, the surgeon may choose not to remove the implant
thus eliminating the risks involved with a second surgery.
4. ADEQUATELY INSTRUCT THE PATIENT. Postoperative care
and the patient’s ability and willingness to follow instructions
are among the most important aspects of successful bone
healing. The patient must be made aware of the limitations
of the implant, and instructed to limit and restrict physical
activities, especially lifting and twisting motions and any type
of sports participation. The patient should understand that
a metallic implant is not as strong as normal healthy bone
and could loosen, bend and/or break if excessive demands
are placed on it, especially in the absence of complete bone
healing. Implants displaced or damaged by improper activities
may migrate and damage the nerves or blood vessels. An
active, debilitated, or demented patient who cannot properly
use weight-supporting devices may be particularly at risk
during postoperative rehabilitation.
5.
CORRECT PLACEMENT OF ANTERIOR SPINAL IMPLANT.
Due to the proximity of vascular and neurologic structures
to the implantation site, there are risks of serious or fatal
hemorrhage and risks of neurologic damage with the use of
this product. Serious or fatal hemorrhage may occur if the
great vessels are eroded or punctured during implantation
or are subsequently damaged due to breakage of implants,