Intraoperative Complications of Penetrating Keratoplasty

Complications Related to Anesthesia

Adequate anesthesia and akinesia are absolutely necessary during penetrating keratoplasty. Under most circumstances, this can be achieved with regional retrobulbar or peribulbar anesthesia. Although rare, the risks of regional blocks include globe penetration or perforation, retrobulbar hemorrhage, expulsive hemorrhage, optic nerve damage, retinal vascular occlusion, prolonged extraocular muscle palsy, seizures, brainstem anesthesia, and cardiac and pulmonary depression. ^, Peribulbar anesthesia has gained favor over retrobulbar anesthesia as it has been shown to achieve similar anesthetic results but with less morbidity. ^{, ,}

General anesthesia carries the advantage of avoiding periocular pressure and may be preferable in patients who are young, anxious, noncooperative, obese, or have discomfort in the supine position. However, general anesthesia may pose significant morbidity and mortality risks to the patient with systemic medical conditions.

Scleral Perforation with Fixation Sutures

Fixation of the globe with devices such as the Flieringa ring ( Fig. 112.1A ) or McNeill–Goldman blepharostat (see Fig. 112.1B ) may be necessary to prevent scleral collapse and facilitate in the suturing of the donor cornea in children, who have elastic sclera, in postvitrectomized eyes, and in aphakic or pseudophakic eyes with anterior chamber intraocular lenses (IOLs) that will be removed. ^, Scleral perforation with the suture needle is a potential complication during the placement of such a device. If perforation occurs posterior to the pars plana, this may result in a retinal tear and possible retinal detachment. When a perforation is recognized, cryotherapy should be applied and the patient should be closely observed postoperatively. To minimize the chance of retinal complications in the event of a perforation, the fixation ring should be sized appropriately and the needle should be passed at or anterior to the pars plana.

To minimize the possibility of scleral perforation, the use of a spatulated needle is preferred over a cutting needle. Since the most significant challenge to safe suture placement is the inability to visualize the sclera directly while passing the suture needle, a modified technique has been described of first performing four small radial conjunctival cuts at the intended sites of suture placement.

Complications Related to Trephination