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Paediatric PK precautions

Dermot McGrath

Posted: Monday, November 2, 2020

Penetrating keratoplasty is extremely challenging in a paediatric patient population, but favourable outcomes may still be obtained with careful case selection, rigorous surgical technique and meticulous postoperative care, according to Nikolas Ziakas MD, PhD.
Speaking at the World Ophthalmology Congress 2020 Virtual, Dr Ziakas, Professor of Ophthalmology at the Aristotle University of Thessaloniki Medical School, Greece, said that a number of factors needed to be considered before embarking on penetrating keratoplasty (PK) surgery in children,
“We need to bear in mind the technical difficulty of the procedure, problems with postoperative care and the likelihood that amblyopia will limit visual rehabilitation. Even if the operation is successful and we have a clear graft and meticulous follow-up care, the reality is that the final visual outcomes are often disappointing in infants,” he said.
Nevertheless, the positive news is that there is often a noticeable postoperative improvement in children’s behaviour, communication and quality of life after PK surgery, even in the presence of cloudy grafts or a measured visual acuity of 20/200 or less, Dr Ziakas added.
The majority of indications for paediatric keratoplasty are congenital, such as Peter’s anomaly, sclerocornea, endothelial dystrophy and congenital glaucoma, with trauma the second single biggest indication.
PK in children requires a different approach than when performed in adult patients, said Dr Ziakas.
“Unique to children is the crucial need for timely optical correction and amblyopia therapy after PK. That is why we need a team approach that includes physicians, parents and optometrists to obtain the best possible outcome,” he said.
Preoperative challenges include dealing with an uncooperative patient, poor visual acuity evaluation and imprecise examination, as well as deciding on the optimal timing for the surgery.
“This is often a balancing act between earlier intervention with the risk of graft failure or rejection and a later intervention with the increased risk of amblyopia,” he said.
Among the multiple intraoperative challenges facing the surgeon in paediatric PK, Dr Ziakas highlighted low scleral rigidity, thinner and more pliable corneas, smaller donor size, smaller anterior segment dimensions, higher posterior vitreous pressure, increased fibrin release and difficult wound closure with the risk of extrusion and suprachoroidal haemorrhage.
Postoperative challenges include the difficulty of conducting routine follow-up examinations, eye rubbing, broken sutures and the risk of infection and wound dehiscence.
“We need constant vigilance and frequent examinations to prevent graft failure,” he said.
Dr Ziakas recommended oversizing the graft by 0.5-to-1.0mm because of the increased elasticity of the infant cornea and sclera, and also using the Price graft-over-host technique to manage positive pressure. This involves suturing the graft across the trephinated host cornea, maintaining a formed anterior chamber.