What Is Mimix Bone Cement Used For In Craniomaxillofacial Surgery?

Q: Dr. Eppley, I am interested in knowing more about Mimix bone cement. Here are my questions:

1) What type of surgery is Mimix mainly used for? 

2) What is the biggest features of Mimix? Could Mimix be placed in any area of the cranial bone?

3) In Genioplasty are there any special techniques in using it?

4) Can Mimix be placed in the gap between a cranial bone flap and the native bone with titanium plating?

5) Can Mimix be used for small defect cranioplasty (less than 25 square cm) for pediatric patients

6) Have you ever experienced Mimix breaking after surgery?

7) Do you have any experience using Mimix on maxillofacial and mandibular bone?

A: Based on my extensive experience with Mimix bone cement in craniomaxillofacial surgery, the answer to your questions are as follows:

1) Mimix is used for two main cranial (skull) purposes: 1) inlay defects of the skull such as burr holes or larger skull defects and 2) as an onlay material for skull augmentation such as aesthetic forehead augmentation or to build up deficient skull contours. There are a wide variety of other maxillofacial uses which ranges from filling in small bone defects and as a contouring material, but the skull makes up the vast majority of its uses particularly as judged by volume used.

2) If one is looking for a natural method of bone reconstruction (hydroxyapatite is similar to bone in chemical composition) of the skull as opposed to using completely synthetic metallic materials. Mimix can be placed in any area of the skull. Since the skull is non-mobile and non-load bearing, it can be used in any location from the temporal fossa to the frontal sinuses.

3) When placing the material in a genioplasty as an interpositional filler, it is important that the implantation site is not too wet with blood. A very wet field interferes with the setting/curing of any hydroxyapatite cement.

4) As a general rule, no. if you are referring to using Mimix in conjunction with titanium plating for cranial flap fixation it can be done but there is little reason to do so directly underneath a fixation plate. It may be used for other bone gaps along the cranial bone flap if they are significant enough in width.

5) Filling in pediatric skull defects would be a common use for Mimix due to its advantages in the growing skull.

6) It is important when using any hydroxyapatite cement to ensure that there is no mobility of the surrounding bone. Mimix is not a bone fixation method, it is a bone graft substitute that must have good stability of the surrounding bone otherwise it may fracture. In my experience I have never seen Mimix fracture or pose a problem in this way but you have to know how and when to use it to avoid this potential concern.

7) Mimix in the maxillofacial region is used as an inlay method only to fill in small bone defects that might otherwise require a graft and into which a dental implant is not intended.

Dr. Barry Eppley

Indianapolis, Indiana