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Post Info TOPIC: Mini Ark prior to Graft?
Would you consider Mini Ark if you knew that if unsuccessful Graft was still possible? [9 vote(s)]

No, Never
11.1%
Yes
55.6%
Maybe, following further research
11.1%
Yes, but only as a last step to preserve my original cornea
22.2%


Executive

Status: Offline
Posts: 397
Date: Sun May 15 9:23 PM, 2005
Mini Ark prior to Graft?
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This is an extract from a previously posted article. It suggests the possibilty of KC regression following Pk... I have included it under the Mini Ark topic because the so called long term success rate, and glowing peer recommendation that corneal graft enjoys  is often stated when denouncing Mini ark.


But here we see that even after 15 years regression can occur in PK ('...a slow long term drift in the axis and magnitude of astigmatism if patients are followed for 10–15 years following PK'), also it is stated that in some cases, the use of corneal incisions are used to (' maintain the strength and integrity of the host cornea'). Here again we see admitted that incisions strengthen rather than weaken corneal tissue.


Extract:


There are few data in the literature on the long term stability of the refraction following PK for keratoconus. The majority of studies reporting on refractive outcomes following PK give results at 18 months to 4 years of postoperative follow up. Long term data on outcomes of PK for keratoconus tend to concentrate on survival rather than recording refractive outcomes. In the absence of published studies, our clinical experience suggests that there continues to be a slow long term drift in the axis and magnitude of astigmatism if patients are followed for 10–15 years following PK. The work presented in this month’s issue of the BJO  by Lim et al on late onset post-keratoplasty astigmatism in patients with keratoconus identifies a subgroup of patients who developed excessive astigmatism years after successful surgery. They highlight an interesting mechanism for the induction of significant astigmatism; the continued progression of the pathological process of keratoconus in the host cornea leading to peripheral corneal thinning. This observation is important for two reasons. Firstly it allows the selection of an appropriate treatment to reduce the astigmatism. They employed compression sutures at the graft-host interface in the area of peripheral thinning, rather than use incision or ablation procedures in an ectatic cornea to flatten the steep meridian. In general, refractive treatments are confined to the donor button or interface since this maintains the strength and integrity of the host cornea, which may later require regrafting for unrelated reasons. However, in this situation thinning of the host cornea is the cause of the increased astigmatism and so a "strengthening" procedure in this area is a logical choice.

Secondly, it demonstrates one of the limitations of penetrating keratoplasty as a treatment for keratoconus where the entire cornea has a tendency to ectasia. The fact that the entire corneal stroma is not replaced allows the pathological process to continue in the remaining host cornea leading to late onset astigmatism. However, it has been shown that performing PKs larger than 8.5 mm increases the likelihood of graft rejection.


Hari



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Anonymous

Date: Mon May 16 11:54 AM, 2005
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Is this proceedure the same as mini-ark but is using a different name?

I have heard of this treatment a few times...

Here is a quote from the link below...

"Corneal wedge resection to treat progressive keratoconus in the host cornea after penetrating keratoplasty
Luca Ilari, MD, Sheraz M. Daya, FRCS (Ed), FACS

We present 3 cases of progressive keratoconus in the host after penetrating keratoplasty PKP that were treated with a wide crescentic excision of the diseased tissue in the host cornea guided by Orbscan II topography (Bausch & Lomb). In all cases, the procedure resulted in a more regular corneal shape with a marked reduction in astigmatism, preventing the need for repeat PKP"

J Cataract Refract Surg 2003; 29:395–401 © 2003 ASCRS and ESCRS



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Executive

Status: Offline
Posts: 397
Date: Sat May 28 2:08 PM, 2005
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Hi Sajeev,


I do remember reading about a woman in Michigan who had a corneal wedge resection to treat her KC. It would be interesting to hear of anyone else who has had the procedure... and their outcomes.


I know it is commonally used POST PK to correct high astigmatism... which again begs the question: Why not use it PRE graft? Oh right, then it would be called Mini ark... bad before - good after, you find the logic,


Hari



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