Pentacon Trial: Partial ENdothelial Trepanation in Addition to Anterior Lamellar Keratoplasty in keratoCONus. A Prospective Multicenter Randomized Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 终止
- 发起方
- UMC Utrecht
- 入组人数
- 14
- 试验地点
- 10
- 主要终点
- Peroperative corneal perforation
研究概览
简要总结
Rationale:
Keratoconus is a progressive, non-inflammatory corneal disease in which irregular refractive properties of the cornea result in loss of visual acuity. Treatment is aimed at improving vision, principally using (rigid) contact lenses. With progression of the disease non-correctable refractive abnormalities and/or corneal scars arise. For these advanced stages of keratoconus, a corneal transplant is the only treatment modality.
New surgical grafting modalities have been developed to create partial thickness grafts, according to the location of corneal pathology. For keratoconus, transplanting only the anterior corneal lamellae lowers long-term graft rejection rates. We utilize a method to enhance the safety of the grafting procedure while better visual outcomes are expected.
Objective:
To investigate the additional value of partial endothelial trepanation (PET) in an anterior lamellar keratoplasty (ALKP) procedure in terms of efficacy and safety in patients with keratoconus.
Study design:
A randomized controlled interventional trial
Study population:
Patients over 18 years old with keratoconus in whom contact lens correction is unsuccessful and who are not suitable for corneal crosslinking.
Intervention:
Patients will be randomly assigned to corneal grafting techniques; partial endothelial trepanation in addition to an anterior lamellar keratoplasty (i.e. the PET group) or a regular ALKP procedure.
Study outcomes:
Risk of per-operative perforation. Secondary, factors contributing to treatment safety and efficacy.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
There is no extra burden or risk associated with participation in this study. All measurements are part of normal clinical practice. Adequate experience is available with both surgical techniques. Study participation has no effect on donor selection. If partial endothelial trepanation (PET) is associated with lower complication rates and better visual outcomes, this might be beneficial in terms of morbidity.
详细描述
Background:
Keratoconus is a progressive, non-inflammatory corneal disease in which irregular refractive properties of the cornea result in loss of visual acuity. Keratoconus usually arise in adolescence, is bilateral and has an estimated incidence of 1:2000. The aetiology of keratoconus is largely unknown, genetic predispositions are currently under investigation. Treatment is aimed at improving vision, principally using (rigid) contact lenses. With progression of the disease non-correctable refractive abnormalities and/or corneal scars arise. For these advanced stages of keratoconus, a corneal transplant is the only treatment modality.
The first corneal transplant for keratoconus was conducted in 1936 by Ramon Castroviejo in New York's Columbia Presbyterian Medical Centre. Ever since, corneal grafting is subject to many technical developments. For over 70 years, a technique is used in which a circular donor disc is cut with a trephine and sutured in a concordantly prepared recipient, called a perforating keratoplasty (PKP).
With the advent of refractive surgery in the years 1990, equipment appeared to split a cornea in horizontal lamellae. This made partial thickness grafting possible, tailoring grafts according to the nature and location of corneal pathology. For keratoconus, only the anterior part of the cornea needs to be transplanted. The posterior (endothelial) part is particularly involved in graft rejections. The chance of graft rejection decreases significantly when the patient's endothelium is left in place.
For keratoconus, this new treatment modality is called a deep anterior lamellar keratoplasty (DALK). The transplanted anterior corneal thickness is maximized, and the patient retains its own endothelium and Descemet membrane, owing to lower graft rejection rates and less secondary cataract formation.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •age equal or above 18 years
- •keratoconus as defined and classified by
- •presence of corneal thinning and protrusion on slit-lamp examination
- •topographic criteria according to KISA% index (>100%)
- •mean corneal curvature map
- •decreased best corrected visual acuity due to corneal scarring or contact lens intolerance
排除标准
- •prior corneal surgery, cross linking, refractive surgery or other treatment modalities
- •(localized) corneal thickness < 200 µm
- •associated corneal endothelial disease on specular microscopy as defined by:
- •<1500 endothelial cells per mm2
- •polymegathism > 0.3
- •pleomorphism < 0.6 (all are measurements of endothelial dysfunction)
- •gross ophthalmic pathology surpassing keratoconus as cause of decreased visual acuity
- •keratoconus-like disease (keratoglobus, pellucid marginal degeneration)
- •associated corneal anomalies (microcornea, macrocornea, buphthalmos, Peters syndrome, ICE-syndrome etc.)
结局指标
主要结局
Peroperative corneal perforation
时间窗: During Surgery. From start to closure of surgical procedure approx. 2h
Peroperative corneal perforation is the biggest drawback of currently utilized grafting procedures (ALKP, 20-30%). Our new technique is believed to be safer, by reducing the number of corneal perforations during surgery. Corneal perforation necessitates converting the procedure to a full-thickness graft with a less favourable long term rejection profile.
次要结局
- Manifest refraction one year post op(One year post-op)
- Contact lens use (soft/rigid/scleral) or spectacle use(one year post-op)
- Self-rated improvement questionnaire(One year post-op)
- Corneal endothelial function one year post op(One year post-op)
- Graft rejection rate(During one-year follow up period)
- Best corrected visual acuity one year post op(One year post-op)