Personal tools
You are here: Home → Products → M-Sphere Orbital Implants → M-Sphere Overview
 

M-Sphere Overview

The M-Sphere® orbital implant is manufactured from MoaBone®, the natural hydroxyapatite mineral matrix of cancellous bone. The bone, of New Zealand origin, is treated to remove the organic components leaving only the hydroxyapatite mineral framework.

M-Sphere® orbital implants are designed to support and impart movement to an artificial eye (prosthesis) after enucleation. Like the mineral portion of human bone, the bony trabeculae within the M-Sphere® provide a completely porous structure which is easily and rapidly incorporated into the tissues. With careful surgical technique it is possible to insert a relatively large M-Sphere® into Tenon’s space and eliminate dead space in the socket. Cosmetically this is highly desirable as it produces a visible bulge behind closed lids giving an impression of a normal closed eye when a artificial eye is not being worn. Furthermore, the movement of the conjunctiva covered orbital implant against the tarsal conjunctiva prevents the accumulation of secretions and maintains a healthy socket. Where customised artificial eyes are not available, a smaller M-Sphere® orbital implant can be used with a stock artificial eye.

In most patients where the tissue is healthy it is not necessary to cover the M-Sphere® with a cap of sclera. However if the tissues are deficient, unduly thin or scarred, donor sclera can be placed over the front of the M-Sphere®.

Advantages of the M-Sphere® orbital implant:

  • The M-Sphere® is a matrix of white, very light, natural hydroxyapatite.
  • The M-Sphere® is completely porous. When buried in the patients tissues it is rapidly organised by host fibrovascular tissue.
  • The M-Sphere® can be easily shaped to suit the individual case. this is done by soaking in antibiotic or saline solution which allows it to be shaped with a pair of scissors.
  • All M-Sphere® products are pre-sterilised for added convenience and safety.
  • Once incorporated into the patients tissue the M-Sphere® resists migration and extrusion. It provides a robust, permanent and mobile support for an artifical eye.
  • When fitted with an artificial eye the M-Sphere® gives an excellent cosmetic appearance without the need for drilling and pegging. However, it may be drilled and pegged in the standard manner if required.

Independent quantitative analysis indicates the M-Sphere® is lighter and more porous than comparative devices derived from bone substitutes.
M-Sphere
Coralline HA
Synthetic HA
Weight
0.31gm
0.79gm
0.62gm
Void Space
90%
65%
50%
Crystal Structure
Solid sheet
of tissue
Sea Urchin
shaped
Cobblestone
like

All MoaBone® and M-Sphere® orbital implants are manufactured and sterilised in strict accordance with international standards and guidelines

Selecting the correct size M-Sphere®

The correct size M-Sphere® is usually between 3/4ths and 7/8ths of the diameter of the eye that has been removed. For example; a 24mm diameter eye has been enucleated. Normally an 18mm to 20mm M-Sphere® would be used. However, if there are complicating factors such as poor blood supply, badly damaged tissues or other factors limiting the vitality of the tissues, a smaller M-Sphere® would be selected.

Available in the following sizes.

Because the M-Sphere® come in a range of sizes, this allows the correct size M-Sphere® to be selected to suit the individual case.

In addition, M-Sphere® orbital packing segments are available for cosmetic reconstructive surgery.

MS 16 M-Sphere 16mm
MS 18 M-Sphere 18mm
MS 20 M-Sphere 20mm
MS 22 M-Sphere 22mm
MS08 Reconstruction pack (8 assorted segments)

Reconstruction Pack

The reconstruction pack consists of a selection of 8 MoaBone® segments (quarter spheres). These are designed to correct cosmetic defects due to post traumatic atrophy of the orbital fat. When packed posteriorly, between the periosteum and the adjacent bone of the lateral and inferior portions of the orbit, they reduce the volume of the bony orbit and displace the remaining orbital fat forward. This corrects the sunken appearance and fills the hollow beneath the brow.

M-Sphere Document Downloads

References:

1) Allen, T. D., Guist’s bone spheres. AM J. Ophthalmol Vol 13, pp226, 1930.
2) McCoy, L. L., Guist’s bone spheres. AM J. Ophthalmol Vol 15, pp960, 1932.
3) Molteno, A.C.B., Van Rensberg, B., Van Rooyen, B., Ancker, E., “Physiological” orbital implant. Brit. J. Ophthal. Vol 57, pp615-621, 1973.
4) Molteno, A.C.B., Antigen-free Cancellous Bone Implants After Removal of an Eye. Trans Ophthal. Soc. N.Z. Vol 32, pp36-39, 1983.
5) Molteno, A.C.B., Elder, M.J., Bone Implants After Enucleation. Australian and New Zealand Journal of Ophthalmology Vol 19(2), pp129-136, 1991.
6) Jordan DR, Huang I, Browstein S, McEachren T, Gilberg S, Gravhovac S, Mawn L, The Molteno M-Sphere, Ophthalmic Plastic and Reconstructive
Surgery, Vol 16(5), pp356-62, 2000.

Document Actions