DePuy Synthes Vacu-Mix Plus Folleto De Instrucciones página 5

The preparation of the bone marrow cavity results in
marrow contents entering the blood stream. Prior to
the application of bone cement to the bone, the cavity
should be thoroughly cleaned by brushing and washing
(lavage) to remove fat, marrow and other debris. The
cavity should be kept as dry as possible to prevent blood
and debris becoming mixed with the cement. Thorough
cleaning of the bone reduces the risk of marrow content
being forced into the vascular system during the insertion
of bone cement and subsequent pressurisation. The
expulsion of bone marrow has been associated with
the occurrence of pulmonary embolisms, and this risk
has been found to be increased in patients with highly
osteoporotic bone and patients diagnosed with femoral
neck fracture. Reaming of the marrow cavity can
have similar effects on mean arterial pressure as the
introduction of bone cement. Marrow cavities should be
vented when the cement is introduced digitally.
The premature insertion of bone cement may lead
to a drop in blood pressure, which has been linked to
the availability of methyl methacrylate at the surface
of the product, although this has not been proven.
This drop in blood pressure, on top of hypotension
induced either accidentally or intentionally, can lead
to cardiac arrhythmias or to an ischemic myocardium.
To reduce this risk the surgeon should avoid early
insertion of the cement and it is recommended that
the mixing and preparation instructions are followed
closely. As a general guide, prior to insertion the cement
surface should appear dull and should not stick to the
surgeon's gloves. The hypotensive effects of methyl
methacrylate are potentiated if the patient is suffering
from hypovolemia.
The surgeon should, by specific training and experience,
be thoroughly familiar with the use of the Vacu-Mix
Plus system together with the properties, handling
characteristics and application of the bone cements.
Because the handling and curing characteristics of bone
cements vary with temperature and mixing technique, they
are best determined by the surgeon's actual experience.
Strict adherence to good surgical principles and
techniques is essential. Deep wound infection is a serious
post-operative complication and may require total removal
of the embedded cement. Deep wound infection may
be latent and not manifest itself for several years post-
operatively.
Consideration should be given to the use of bone cement
in patients diagnosed with femoral neck fracture, as some
published literature has indicated there is a potential for
increased mortality compared with uncemented techniques.
As the liquid monomer is highly volatile and flammable,
the operating room should be adequately ventilated to
eliminate as much monomer vapour as possible. Ignition
of monomer fumes caused by use of electrocautery
devices at surgical sites near freshly implanted bone
cements has been reported.
Store the sealed outer pack below 77°F (25°C) and
protect it from light to prevent premature polymerisation
of the liquid monomer component. Always check the
condition of the liquid monomer before performing the
procedure. Do not use the liquid monomer if it shows any
sign of thickening or premature polymerisation. Do not
use the product after the expiration date.
Caution should be exercised during the mixing of the
two components to prevent excessive exposure to
the concentrated vapours of the monomer, which may
produce irritation of the respiratory tract, eyes, and
possibly the liver. If the liquid component comes into
contact with the eyes, wash with copious amounts of
water. Concentrated vapours of the liquid component
may have an adverse reaction with contact lenses.
Personnel wearing contact lenses should be informed
and limit their exposure. Guidance from contact lens
manufacturers regarding exposure to irritating and
noxious vapours should always be followed.
Methyl methacrylate has been demonstrated to cause
hypersensitivity in susceptible persons, which may result
in an anaphylactic response.
Inadequate fixation
events may affect the cement-bone interface and lead to
micromotion of the cement against bone surfaces, which the
cement is in contact with. A fibrous tissue layer may develop
between the cement and the bone. Long term follow-up is
advised for all patients on a regular scheduled basis.
The completion of cement polymerisation occurs in the
patient and is an exothermic reaction with considerable
liberation of heat. The long term effects of the heat
produced in situ have not yet been established.
The safety and effectiveness of the gentamicin bone
cements in pregnant women or in children has not yet
been established. Gentamicin bone cements should not
be used during the first third of pregnancy, and during
the rest of the pregnancy period should only be used
in life-threatening illnesses. Gentamicin bone cements
should only be used in children for limb preservation
where no other procedure is likely to give a good chance
of successful treatment.
PRECAUTIONS
The use of bone cement requires collaboration and
consultation between the surgeon and the anaesthetist.
The anaesthetist should be told during the operation
when the bone cement is implanted.
Contact of monomer with the skin or mucous membranes
should be avoided. The liquid component of bone
cements has caused contact dermatitis in those handling
and mixing them. Strict adherence to the instructions for
mixing the powder and liquid components may reduce
the incidence of this complication.
The liquid component of bone cement is a powerful lipid
solvent. This liquid component should not be allowed to
come into contact with rubber or latex gloves. Wearing
of a second pair of gloves and strict adherence to the
mixing instructions may diminish the possibility of
hypersensitivity reactions.
Upon application of the bone cement it is important to
maintain the positioning of the prosthetic component until
the completion of the polymerisation process. This must
be done in order to maintain proper fixation.
It is recognised that for some applications, for example
femoral head resurfacing, the early use of cement is
preferred in some cases. There is currently little or no
consensus, or long-term clinical data, as to the potential
risks to the patient associated with this method. This should
be borne in mind when choosing to adopt such practices.
Implantation of a foreign body in the tissues increases
the normal risk of infection associated with surgery
following operation. Evidence from clinical investigations
clearly indicates the necessity for strict compliance to
good aseptic surgical technique. Following the operation
the patient should be advised that in the event of an
intercurrent infection they must immediately seek medical
advice in order to reduce the risk of infection to the implant.
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or unanticipated post-operative