Inion CPS^® products FAQ

They are made of a blend of rigid and elastic polymers selected for their strength, malleability and degradation properties. These polymers blends make up Inion Optima^TM family of biomaterials. The individual polymers used at the Inion CPS^® system are:
- L-lactide
- D,L-lactide (not in CPS Baby)
- Glycolide (only in CPS Baby)
- Trimethylene carbonate


By tailoring the combinations and proportions of polymer selections, fabrication processes and product designs, each element of the Inion CPS^® system has optimal strength, malleability and degradation profiles to meet its specific clinical requirements.

There are many differences but the most notable are:

1) Inion CPS^® is currently the only comprehensive biodegradable system available, i.e. comprising plates and screws suitable for all areas of the facial skeleton with each element tailored for specific clinical applications.

2) The properties of Inion CPS^® uniquely enable four screw insertion methods including Tacker, plus hot &cold plate adaptation.

3) Inion Optima™ polymers are completely or substantially amorphous, even after moulding or processing, which ensures that Inion implants completely biodegrade over a short period of time. Other biodegradable implants are made from polymers with a higher order of crystallinity, which increases the degradation time, sometimes to many years.

Other than composition, structure & processing of the Inion Optima^TM blend used, degradation times depend on a number of factors including:
- implant mass
- implantation area

As a guide, the time for total degradation of Inion implants are:
1.5mm CPS Baby 2 to 3 years
1.5,2.0 & 2.5 mm CPS 2 to 4 years

The implants degrade by hydrolysis and over a period of time are metabolized through natural processes in the body into carbon dioxide and water which are then exhaled and excreted. Host tissue i.e. bone or soft tissue, grows into the space occupied by the implant as it degrades.

Inion Optima™ materials are substantially amorphous. Amorphous polymers have a random structure and are completely & more easily degraded leaving no crystalline debris,.

The Inion CPS^® System has been produced to the following equivalents:

+ 1.5 mm CPS suitable for use in areas where titanium 1.0-1.2 mm used, i.e. upper 3rd facial skeleton (periorbital, antral wall, cranium).

+ 2.0 mm CPS suitable for use in areas where titanium 1.5-1.7 mm used, i.e. mid-face (incl. our strengthened orthognathic plates for LeFort 1 maxillary osteotomies)

+ 2.5 mm CPS suitable for use in areas where titanium 2.0 mm is used, i.e. mandibl

No. All Inion implants are packed as single-use only. The increasingly stringent decontamination regulations as a result of HIV and vCJD mean that only all implants, even metal implants, will soon have to be single-use only.

To maintain the desired position of the bone fragments, it is essential that the plate is precisely adapted. For the sake of just two minutes, it is therefore recommended that the plate warmed prior to application.

There is no specified time limit for leaving the plates in the waterbath and it is important that the activated plate is instantly available to the surgeon when needed. It is therefore worthwhile ensuring that the plate is placed in the water bath in plenty of time.

Plates need to be immersed for two minutes to reach optimum malleability. They can be put back in the water bath at any time during the procedure for reheating . If dipped into the bath for a few seconds, the plates will just soften. If left in the bath for 30+ seconds, they will return to their original flat shape.

The plate can be adapted even after initial bending. Simply reactivate by replacing the plate in the Inion Thermo^TM water bath. If dipped in for a few seconds, the plate will just soften to allow fine adjustments. If left in the bath for 30+ seconds, it will return to its original shape.

No. The screw holes can usullay be seen on post-operative X-rays.

Yes. The plates need to be in direct contact with fluid which is 55 degrees Centigrade to become fully malleable. A drink which is not hot enogh to burn muscosal tissue will not affect the implants.

The screws can be used as self-tapping screws only in thin or soft bone. When self tapping the surgeon needs to take care to stop once the screw head engages in the plate countersink because it is harder to feel the moment of engagement.

It is necessary to tap in thick and dense bone. However, tapping is not required when using the Tacker.

No.

Once the surgeon is used to the feel of the system, emergency screws are rarely needed. However, there is an emergency screw in the 1.5mm CPS Baby, 1.5mm CPS and 2.0mm CPS screw rings.

If an emergency screw is needed when using the 2.5mm CPS system, a single packed 2.8mm screw can be used as an emergency screw and cut to the required length.

A new screw of the same size can be inserted following re-drilling and tapping directly into the original screw positions.

Providing the screw heads have not been deformed the screws can be unscrewed and removed. If it is not possible to remove them, the heads can be taken off and the plate removed for repositioning.

The drilling and tapping technique is critical for good screw engagement. Drilling must be mono-axial (one direction) with a single, smooth, in and out movement. If the drill is left running in the bone, the hole will be too large.

The tapping, which is done to cut threads in the bone for the engagement of the screw, must be done gently and slowly and without undue movement or force. After tapping to the required depth, the tap must be gently unscrewed and not pulled out.

Other reasons for the non-engagement of screws are:
- bone too soft (can be found close to fracture sites)
- "whipping" of the drill, which makes an eccentric hole (check drill handpiece before the start of the procedure).

It is important that the screws are NOT over-tightened, because this can cause the fine pitch to pulp the bone between the threads so the screws cannot grip.

When using titanium, some surgeons go back to a seated screw and retighten - this is not necessary even with titanium (as it can damage the bone), but was a technique introduced to ensure a passive fit when less flexible stainless steel plates were first popularized.

This is definitely not advisable with biodegradable implants - once the screws are seated in the plate, they can be left undisturbed with confidence.

Surgeons are used to feel of titanium which requires less delicate handling and where the screws are self-tapping. They soon learn to get the feel of Inion CPS^® screws and to recognize when the screw is "binding" in the bone and the amount of pressure they can apply.

The Inion Tacker^TM pushes the screws in so that they act more like rivets.

No. But if you need to reposition the screw, the head can be removed and a new hole drilled through the original screw, if needed.

The Inion Tacker^TM should be processed through a sterile service department with all other surgical instruments. It is dismantled for washing in a washer disinfector and then put back together again before sterilization.

A guide to disassembly and reassembly is provided but the procedure is easy, involving on 5 removable parts.

You can download Inion Tacker^TM dissambly and assembly instructions from below

Tacker cleaning.pdf (142.34 kilobytes)

No

The 2.0mm CPS Orthognathic Plates can be easily cut down with scissors if required. Two 2.0mm CPS Orthognathic L Plates Left & two 2.0mm CPS Orthognathic L- Plates Right are used most frequently for Le Fort I maxillary osteotomies. Commonly one superior hole is removed for the anterior plates & one superior hole & one distal hole for the posterior plates.

The 2.5mm CPS plates are suitable for the mandible for both fracture fixation and orthognathic surgery, i.e. sagittal split osteotomy. There are also 2.8mm BSSO screws for bicortical screw fixation, if preferred.

The techniques are the same as for titanium plates and screws i.e. two plates are required for mandibular symphyseal fractures to resist torsional forces. If there is not enough room both above and below the mental nerve in the parasymphysis to fit two 2.5mm CPS Plates, then one 2.0mm 6-Hole Orthognathic Plate (strengthened material) and one 2.5mm can be used.

The Inion CPS^® Baby plates are designed to be a little more flexible but should not present problems when holding the repositioned fragments. The 6mm screws would not improve the rigidity of the fixation. They would just increase the screw pull-out strength.

Other systems on the market may feel more rigid because they are not designed specifically for pediatric craniofacial surgery. As a consequence they are less malleable and slower absorbing than Inion’s CPS^TM Baby. The Inion adult systems are comparable to many competitors implants and give greater rigidity. However, they are slower to biodegrade which is not ideal for pediatric cases when it is very important not to restrict growth.

This choice must be based on clinical judgment. The 2.8mm BSSO screws have a shear strength of about 228N. According to Champy et al, the maximum biting force of a young man with good dentition is 600N but post-operatively this would be significantly less.

Some surgeons use only tow metal screws for BSSO because they prefer a more flexible fixation to allow for condylar repositioning. However elastics are essential.

The Inion Tacker^TM cannot be used transbuccally. The tip is too short and it is not really suitable for the mandible.

There is a transbuccal instrument (INS-9046) which is used with the long screwdriver blade (INS-9040) and long drill bits and taps. Manual tapping is recommended for the mandible, especially transbuccally, because the screws are usually being placed around the angle of the mandible where the bone is most dense.

The Inion Tacker^TM can be hard to use in some pediatric craniofacial cases because
a) the bone surface can be very curved
b) the bone fragments are hard to hold stable on the table
c) the bone fragments are not stable in situ (resting on the soft brain)
d) the bone is soft in some areas and extremely dense in others

The Inion Tacker^TM will not fire the screws accurately into the bone if it is held distant from the plate. The Inion Tacker^TM tip must be resting firmly on the plate. With practice (and patience) surgeons will find the Inion Tacker^TM a useful tool, but not for every screw. They will just choose when to use it, depending on the bone.

It can be difficult to see the X slot in the transparent screws, particularly for the small 1.5mm screws. The following guidelines will help:
- Place the screw ring on a firm, flat surface and secure with your finger
- The screw driver should be at 90 degrees to the screw for pick up. Align the screw driver gently with the screw head.
- Turn the screwdriver gently until you notice the screw is rotating with the screw driver and then push the screw driver firmly into the screw.
- Rotate the screw slightly as you withdraw it to loosen it from the screw ring.

The screw is now mounted on the tip of the screw driver and ready to be used.