Osteo-odonto-keratoprosthesis (OOKP), or ‘tooth in eye surgery’, is a medical procedure involving removing a patient’s tooth to replace the cornea and inserting a tiny lens before being implanted into the eye.
As of the moment, the intersection between dentistry and medicine hasn’t been explored too much, however using teeth, a body part that most people have an excess of, is useful in being able to maximise the potential of the body’s own properties.
First described by Italian Professor Benedetto Strampelli in the early 1960s and modified by Falcinelli [1], creating the modified osteo-odonto-keratoprosthesis (MOOKP), the procedure is used in patients with bilateral end-stage ocular surface disease.
The procedure is still rarely practiced and as of the moment, only one surgeon, Professor Christopher Liu, can do the operations in the UK.
OOKP is usually reserved as a last resort for patients with severely rare types of corneal blindness and cases of bilateral end-stage ocular surface diseases whereby other methods of treatment and surgery have been ineffective.
Some severe autoimmune diseases can also be approached with OOKP:
- Cicatricial trachoma
- End-stage autoimmune dry eye disease; Sjögren’s and graft-versus-host disease
- Severe exposure keratopathy
- Stevens-Johnson syndrome (SJS)
- Toxic epidermal necrolysis (TEN)
The MOOKP is carried out in two stages done 4–5 months apart, each lasting 6 to 8 hours.
Stage one:
Firstly the patient’s tooth with some jawbone is removed and cut into a block.
Half the root is removed, pulp is removed and the dentine of the tooth is polished to the desired thickness.
Through the root of the tooth remaining, a hole is drilled and a plastic lens or optic cylinder is placed and set with acrylic bone cement, or universal resin cement.
Then the tooth and lens are sutured in place, into a pocket of skin underneath the opposite eye to the one it will be implanted into.
A piece of skin from inside the patient’s cheek is cut and stitched over the eyeball being operated on, covering the cornea and sclera with the conjunctiva or with lid suturing; for the time being, this forms the front of the new eye.
For 4 to 5 months, the patient will have lived without being able to see anything due to the skin covering the eye. By then, the tooth will have grown its own soft tissue and the cheek skin over the patient’s eye will have developed circulation.
Stage two:
In the second stage of MOOKP procedure, the tooth is retrieved from the pocket of skin and excess tissue removed, ensuring that some is left for stitching.
The cheek skin that had been covering the eye is carefully peeled back, and then the entire front of the eyeball is removed; this part of the procedure can’t be reversed.
The tooth and lens are then implanted into the eye and the cheek skin stitched back leaving a small hole for the lens. The skin now forms the front of the patient’s eye.
If the procedure is successful, the patient will recover their sight as their eye would have developed circulation and the brain begins to recognise and process the images now reaching the retina.
If unsuccessful, any remaining sight they had before surgery would be lost.
MOOKP has produced good long-term functional success rates. The largest study so far, included 181 patients and showed a 93.9% success rate, and at 18 years of follow up, there was an 85% probability of retention of vision.
But as with any surgery, especially with one so high risk, and specialised as MOOKP is, there are several complications including:
- Lamina-resorption } potentially leading to anatomical failure.
- Glaucoma
- Choroidal/retinal detachment
- Vitreous hemorrhage
- Endophthalmitis
How feasible is making OOKP a more widespread procedure in medicine?
I find it unlikely that OOKP will become a more widely utilized procedure.
According to NHS England, only 5 patients annually are expected to undergo the procedure, with 60 patients being followed up on each year. Due to the high number of professionals required for each section of the surgery, and due to the lack of professionals specialized in this specific procedure and due to the costs, estimated to be around $55,150, as proposed in a paper by Dong et al, I can’t see OOKP becoming a popularized option for those wanting to regain vision. However, as a procedure that can highly improve the quality of life for some, and treat blindness and visual impairments highly effectively, it has much potential to grow [7].
Conclusion:
Modified OOKP surgery for corneal blindness can provide longterm, anatomically stable vision retention as well as an effective, rehabilitating recovery of the cornea. I think that OOKP is an interesting intersection between medicine and dentistry, and as there’s not too much research, and cases of OOKP being carried out, due to its highly fragile nature, and lack of professionals that are trained to carry it out, it would be an exciting surgical process to see further developed. Despite the complications that OOKP can carry along with it, considering its long term benefits, and its ability to restore vision in patients, it can impact many more patients in future.
Nara Ito, Youth Medical Journal 2022
References:
[1] Falcinelli, G., Falsini, B., Taloni, M., Colliardo, P., & Falcinelli, G. (2005). Modified osteo-odonto-keratoprosthesis for treatment of corneal blindness: long-term anatomical and functional outcomes in 181 cases. Archives of Ophthalmology, 123(10), 1319-1329.
[2] Basu, S., Pillai, V. S., & Sangwan, V. S. (2013). Mucosal complications of modified osteo-odonto keratoprosthesis in chronic Stevens-Johnson syndrome. American journal of ophthalmology, 156(5), 867-873.
[3] Zarei-Ghanavati, M., Avadhanam, V., Perez, A. V., & Liu, C. (2017). The osteo-odonto-keratoprosthesis. Current opinion in ophthalmology, 28(4), 397-402.
[4] Tan, A., Tan, D. T., Tan, X. W., & Mehta, J. S. (2012). Osteo-odonto keratoprosthesis: systematic review of surgical outcomes and complication rates. The ocular surface, 10(1), 15-25.
[5] Sawatari, Y., Perez, V. L., Parel, J. M., Alfonso, E., Falcinelli, G., Falcinelli, J., & Marx, R. E. (2011). Oral and maxillofacial surgeons’ role in the first successful modified osteo-odonto-keratoprosthesis performed in the United States. Journal of oral and maxillofacial surgery, 69(6), 1750-1756.
[6] Hille, K., Landau, H., & Ruprecht, K. W. (1999). Improvement of the osteo-odonto-keratoprosthesis according to Strampelli: influence of diameter of PMMA cylinder on visual field. Graefe’s archive for clinical and experimental ophthalmology, 237(4), 308-312.[7] Dong, D., Tan, A., Mehta, J. S., Tan, D., & Finkelstein, E. A. (2014). Cost-effectiveness of osteo-odonto keratoprosthesis in Singapore. American journal of ophthalmology, 157(1), 78–84.e2. https://doi.org/10.1016/j.ajo.2013.08.004
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