Osteo-odonto-keratoprosthetics is a complex surgical technique for restoring vision with severe damage to the surface of the eye . The tooth serves as a blank for osteo-odonto-keratoprosthesis. The operation is performed extremely rarely, significantly inferior in terms of the achieved quality of vision to the much more common donor corneal transplant .
At the first stage of the operation, a thin plate is cut out of a tooth removed from the patient or his relative. A hole is made in the plate into which an artificial lens or cylinder is inserted, then the structure is implanted under the patient’s skin for a period of 2 to 4 months, after which the complex is implanted in the patient’s eye.
The procedure was first developed by Italian professor Benedetto Strampelli in 1963, [1] then modified by his student Giancarlo Falcinelli.
Content
Indications and effectiveness
The operation is performed for severe chemical burns of the eye, for Steven-Johnson syndrome , trachoma , severe pemphigoid , Lyell's syndrome , multiple rejections of transplanted corneas and other disorders if vision cannot be maintained by less radical methods. [2]
In the long run, there is a noticeable risk of resorption of the plate, especially when the graft is taken from another person, as well as glaucoma . Statistics from various studies estimate the risk of mechanical dysfunction in 15% (out of 181 patients), [3] 19% (out of 36 patients), [4] and even 34% (out of 145 patients). [5] Visual acuity after surgery also decreases markedly over time: according to one study, after ten years, only 38% of patients retain visual acuity of more than 0.05. [5] A more rare form of prosthetics using an osteo-keratoprosthesis is associated with lower rates of engraftment and visual acuity. [five]
Operation Plan
The operation takes place in two stages:
At the first stage, a healthy tooth, canine or premolar is removed from the patient, sometimes after preliminary radiography . Then a superficial keratectomy is performed , in which the surface of the cornea is removed to the Bowman layer and a flap of the mucous membrane taken from the inner surface of the patient’s cheek is sewn on top. A thin plate is cut out of the tooth, a hole is drilled into it, into which a plastic cylinder is inserted, and the entire complex is sewn into the patient's cheek.
In the second stage, sometimes after a preliminary assessment of the plate using MRI , the transplant complex is excised from the cheek. An incision is made on a flap of the mucous membrane that has engrafted over the eye. To fix the eye for the duration of the operation, a Flieringa ring can be used. The graft is inserted into the eye after preliminary removal of some intraocular structures. The flap of the mucous membrane is sutured again, a small area is cut out above the transparent plastic cylinder.
After the final engraftment, the patient can use a scleral lens for cosmetic purposes, which looks like a normal eye with a pupil and iris surrounded by a white sclera.
Notes
- ↑ Strampelli B., Valvo A., Tusa E. [Osteo-odonto-keratoprosthesis in a case treated for anchylobepharon and total simbleraphon] (Italian) // Ann Ottalmol Clin Ocul . - 1965. - June ( t. 91 , No. 6 ). - S. 462-479 . - PMID 5839953 .
- ↑ Viitala R., Franklin V., Green D., Liu C., Lloyd A., Tighe B. Towards a synthetic osteo-odonto-keratoprosthesis (English) // Acta Biomater : journal. - 2009 .-- January ( vol. 5 , no. 1 ). - P. 438-452 . - DOI : 10.1016 / j.actbio.2008.07.008 . - PMID 18706878 .
- ↑ Falcinelli G., Falsini B., Taloni M., Colliardo P., Falcinelli G. Modified osteo-odonto-keratoprosthesis for treatment of corneal blindness: long-term anatomical and functional outcomes in 181 cases // Arch. Ophthalmol. : journal. - 2005 .-- October ( vol. 123 , no. 10 ). - P. 1319-1329 . - DOI : 10.1001 / archopht.123.10.131919 . - PMID 16219722 .
- ↑ Liu C., Okera S., Tandon R., Herold J., Hull C., Thorp S. Visual rehabilitation in end-stage inflammatory ocular surface disease with the osteo-odonto-keratoprosthesis: results from the UK // Br J Ophthalmol : journal. - 2008 .-- September ( vol. 92 , no. 9 ). - P. 1211-1217 . - DOI : 10.1136 / bjo.2007.130567 . - PMID 18511541 .
- ↑ 1 2 3 Michael R., Charoenrook V., de la Paz MF, Hitzl W., Temprano J., Barraquer RI Long-term functional and anatomical results of osteo- and osteoodonto-keratoprosthesis (Eng.) // Graefes Arch. Clin. Exp. Ophthalmol. : journal. - 2008 .-- August ( vol. 246 , no. 8 ). - P. 1133-1137 . - DOI : 10.1007 / s00417-008-0850-3 . - PMID 18491123 .
Links
- Modified Osteo-odonto Keratoprosthesis - "Modified Osteo-odonto-keratoprosthesis", a description of the operation with illustrations.
- Cross sectional diagram describing the anatomy and structure of an osteo-odonto-keratoprosthesis. - a cross section showing the structure of the eye with a prosthesis after surgery. Br J Ophthalmol. 2005 August; 89 (8): 956-959