SURGICAL SIMPLEX®P


PRESENTATION
PREPARATION AND ADMINISTRATION
CONTRA-INDICATIONS
WARNINGS, PRECAUTIONS AND INTERACTIONS
ADVERSE EFFECT
SIGNIFICANT MEDICAL INFORMATION
PHARMACEUTICAL PRECAUTIONS



 

PRESENTATION

The packing of surgical use radio-opaque Simplex®P cement includes two sterile components.
One of the composants is a flask containing 20 ml of a colourless monomer, a flammable liquid with a slightly sweetened bitter odour, composed of :
Methyl methacrylate (monomeric), 19.5ml N N-dimethyl para toluidine, 0. 5ml Hydroquinone, USP 1.5mg.
Hydroquinone is added to prevent  premature polymerization which can occur under certain conditions - ex : exposure to the light, high temperatures.
N N - dimethyl para toluidine is added to enhance the hardening of the therapeutic finished compound.
The liquid component is sterilized by membrane filtration.

The other composant is a sachet containing g of finely divided powder made up of the following:
Methyl methacrylate - styrene  Copolymer 30.0 g
Polymethylmethacrylate 6.0g
Sulphate Barium pH Eur. 4.0g

The powder is sterilized by  gamma irradiation. The Barium Sulphate incorporated in surgical use radio-opaque Simplex®P cement acts to provide a contrast during the radiological examination. 
However in my opinion, it is essential to add tantalum or tungsten powder because the Barium sulphate is not opaque enough. When it is used, the powder and the liquid are mixed together, producing an exothermic reaction which results in a paste-like soft, flexible polymer being produced. As the reaction progresses, a compound resembling hard cement is formed, within a few minutes.

DOSING

For  vertebroplasty 1 volume of solvent is used for 4 volumes  of powder.

PREPARATION AND ADMINISTRATION

The liquid monomer, the flask and its packing are pre- sterilized. The product must not be used if the packaging is damaged. To mix, completely empty the sachet containing the powder into a suitable, sterile inert mixer. Add all the liquid contained in the flask to the powder. The liquid must be added to the powder and not the powder to the liquid. Mix using a suitable inert device, stirring until the powder is completely saturated with the liquid. For use with a syringe, mix thoroughly for between 1 and 2.5 minutes. Introduce the  liquid cement into a suitable injection device, and inject into the bone.

CONTRA-INDICATIONS

The use of surgical use radio-opaque Simplex®P cement is contra-indicated in patients allergic to one or the other of its constituents. The use of the product is contra-indicated in the event of infectious arthritis.

WARNINGS AND PRECAUTIONS AND INTERACTIONS

The liquid monomer and the powder must be meticulously mixed. The data drawn from in- vitro studies showed that the widening out of the monomer is due mainly to the speed of the mixing and secondly to the length of time the mixing takes. The end of the polymerization process which occurs inside the patient's body is an exothermic reaction causing a noticeable amount of heat to be released.
Temperatures recorded during polymerization may rise to l10° Centigrade.
The extent of tissue damage caused by the long-term effects of the heat is not known.
Particular precautions must be taken in order to detect and to correct the transitory fall of the blood pressure which can occur when the product is injected into the bone.
As the monomeric liquid is highly volatile and flammable the operating theatre suite will have to be equipped with adequate ventilation in order to eliminate a maximum quantity  of monomeric vapour.
Precautions will have to be taken during the mixing of the two components  in order to avoid excessive exposure to the concentrated monomer vapour which can cause an irritation of the respiratory tracts and eyes, and even of the liver. The liquid component is an active lipidic solvent.
Predisposed subjects are likely to suffer dermitis on contact.  The wearing of a second pair of surgical gloves and a strict adherence to the mixing instructions can decrease the possibility of  over-sensitive reactions. The compound should not come into direct contact with  sensitive tissue or be absorbed by the body.
Because of the lack of appropriate information, use of the product is not recommended in young patients.
The case of pregnant woman : although the results of the study of animal teratology are negative, it is necessary to weigh the benefits of the treatment against the possible dangers to the mother and the foetus in the event of pregnancy or among women of child-bearing age.
 
 

ADVERSE EFFECT

The most significant undesirable reactions, some with a fatal outcome, connected with the use of acrylic cement are :
. heart failure,
. myocardial infarction,
. pulmonary embolism,
. cerebral vascular accidents.
The adverse effects which are the most frequently reported are :
. a transitory drop in blood pressure.
. thrombophlebitis,
. haemorrhaging and haematoma.
 

SIGNIFICANT MEDICAL INFORMATION

The adverse effects which affect the cardiovascular system have been attributed to the widening of the monomeric liquid loose in the circulatory system.  Moreover more recent data indicates that the monomer causes fast hydrolysis in methacrylic acid and that a significant quantity of the circulating methacrylate is in the form of free acid rather than the form of methyl ester.The correlation between the changes in the concentrations of methacrylic acid and methyl methacrylate circulating in the body and the variations in blood pressure was not established.
The deferred episodes of hypertension occur rather more among patients whose blood pressure is high or higher than the normal, in patients in hypovolemy, and the individuals with pre-existent cardiovascular anomalies.
If a hypotensive reaction occurs, this  can begin 10 to 165 seconds after the application of the cement and can last between 30 seconds and  5-6 minutes.
Although the etiology of the heart failure is uncertain, it can be due to the direct effects of an embolism or secondly to hypoxia produced by the phenomenon of pulmonary embolism.

PHARMACEUTICAL PRECAUTIONS

Store in the dark  and at temperatures lower than 25°C.
Do not use this product after its expiry date.
 

PRESENTATION

Unit box or box of 10 units - each unit contains :

1 sterile sachet  containing 40 G of sterile polymeric powder, 1 sterile flask containing 20 ml of sterile monomeric liquid.
References : box of 10 units individual box