Microsurgical Robot-assisted Corneal Transplant

Context Transfixing keratoplasty was developed in the early 20th century. The aim is to replace the entire central cornea with a corneal allograft. This microsurgical procedure is performed with the aid of an operating microscope, and under general anesthetic to ensure optimal control of the absence of movement and arteriovenous pressure throughout the procedure.

Suturing is therefore an essential part of transfixing keratoplasty. They determine the congruence of the tissue edges and the distribution of tension applied to the sutures, thus modulating the curvature (astigmatism) of the graft. This curvature will determine the optical properties of the eye, and hence its acuity and the patient's visual recovery. A topical immunomodulatory local treatment (corticosteroids and/or ciclosporin eye drops) is administered for several years; no systemic treatment is used. Sutures are usually removed 6 months to 1 year after surgery. Current indications are major declines in visual acuity - generally below 4/10 with the best possible correction - associated with i) severe keratoconus, the most frequent indication, ii) failed anterior grafts, iii) full-thickness central corneal scars, and iv) hereditary stromal dystrophies.

Robot-assisted surgery has developed considerably over the last twenty years, with procedures now routinely performed in macro- and endoscopic surgery (mainly urology, obstetrics and visceral surgery). Very recently, engineering advances in precision motion control and mechanical miniaturization have enabled the development of robots dedicated to microsurgery. The Symani® Surgical System (Medical MicroInstrument, Pisa, Italy) has been used and evaluated in animals and humans over the past two years for vessel and nerve microsurgery. The Symani® robot is equipped with forceps and a needle holder capable of handling fragile tissue, as well as microsurgical needles and wires (8/0 to 12/0). The Symani® robot has recently been CE-marked for microsurgery [appendix 1]. To date, there is only one study - ex vivo and in animals - on the feasibility of its use in ocular surgery. On the basis of the robot's capabilities and its CE mark, the investigators have carried out preliminary experiments, enabling us to envisage robot-assisted keratoplasty in humans.

On the basis of our preliminary results, the investigators hypothesize that it is possible to use the Symani® robot's assistance to perform the major surgical stage of transfixing keratoplasty, i.e. the sutures between the graft and the recipient cornea, in humans.

Objectives :

• Main:

  1. Evaluate the feasibility, and intraoperative intercurrent events of robotic assistance during transfixing keratoplasty,
  2. Identify possible early and late postoperative intercurrent events/adverse events related to robot use.

• Secondary :

  i) Evaluate the impact of robotic assistance during transfixing keratoplasty on postoperative corneal anatomical outcome (graft curvature).

ii) Assess the impact of robotic assistance on refraction and visual outcome in the medium term: 3 months iii) Evaluate the mean degree of astigmatism post robotic-assisted grafting, so as to be able to calculate the number of subjects required for a subsequent study of the superiority of robotic-assisted surgery over usual conventional surgery.

iiii) Evaluate the additional cost of robotic-assisted surgery. iv) Evaluate the quality of life before and 3 months after the intervention Type of study: pilot feasibility study, monocentric, interventional. Population: Ten consecutive adult patients requiring transfixing keratoplasty who agreed to participate by signing an informed consent form.

Investigation plan : The study will be offered to patients scheduled for penetrating keratoplasty. Clinical follow-up will be conducted at Day 1, Day 7, Day 30. Final clinical and paraclinical check-up at Day 90 and end of participation.