Descemet's membrane endothelial keratoplasty for pseudoexfoliation syndrome: a case series.

BACKGROUND: To evaluate the clinical outcomes and features of Descemet's membrane endothelial keratoplasty (DMEK) for eyes with pseudoexfoliation syndrome (PEX). METHODS: In this retrospective study, 37 DMEK cases were reviewed from available medical records. Patients who exhibited endothelial dysfunction derived from PEX or Fuchs endothelial corneal dystrophy (FECD) and successfully underwent cataract surgery about four weeks before DMEK were enrolled. The best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), endothelial cell density (ECD), and incidence of intra-operative/post-operative complications of DMEK were analyzed. RESULTS: This study included 14 eyes of 14 patients (PEX: n = 6, FECD: n = 8). There was no primary graft failure. In the PEX group, BSCVA improved from 0.67 ± 0.28 at the preoperative point to 0.43 ± 0.14 at 1 month, 0.27 ± 0.10 at 3 months, and 0.19 ± 0.08 at 6 months after DMEK. The donor corneal ECD was 2704 ± 225 cells/mm2 at the preoperative point and decreased to 1691 ± 498 cells/mm2 at 1 month, 1425 ± 366 cells/mm2 at 3 months, and 1281 ± 340 cells/mm2 (52.7 ± 11.7% less than ECD of the donor graft) at 6 months after DMEK. None of the patients required rebubbling. When compared with the FECD group, no statistical difference was observed in CCT (p = 0.821); BSCVA (p = 0.001) and the reduction rate of ECD (p = 0.010) were relatively worse. CONCLUSIONS: DMEK is effective for the treatment of endothelial dysfunction due to PEX.

Glaucoma Implant Tube Lumen Obstruction Visualized Using Anterior Segment Optical Coherence Tomography.

We report a case of glaucoma implant tube lumen obstruction visualized with anterior segment optical coherence tomography (ASOCT) and present its surgical management. The patient was a 66-year-old man with refractory glaucoma associated with traumatic aphakia in the right eye after trabeculectomy, several bleb needling procedures, and scleral fixation of the intraocular lens with pars plana vitrectomy. Finally, we performed Baerveldt implantation at the pars plana of the temporal inferior quadrant with a several Sherwood slit. However, his intraocular pressure (IOP) was >30 mm Hg despite maximum medication for several weeks. We attempted second vitrectomy and completely removed vitreous around the tube tip; however, his IOP remained around 40 mm Hg for several days after the surgery. Therefore, we suspected tube obstruction at the extraocular point of the tube lumen and used ASOCT for assessment. ASOCT revealed material in the tube lumen. We pulled out the tube and then crushed and extruded the obstructing material from the tube tip. We then refixed the tube at the same place and achieved good IOP control after the surgery. Our findings indicate that ASOCT is useful for diagnosing glaucoma implant tube lumen obstruction and surgical decision-making.

Load evaluation of the da Vinci surgical system for transoral robotic surgery.

Transoral robotic surgery, performed with the da Vinci surgical system (da Vinci), is a surgical approach for benign and malignant lesions of the oral cavity and laryngopharynx. It provides several unique advantages, which include a 3-dimensional magnified view and ability to see and work around curves or angles. However, the current da Vinci surgical system does not provide haptic feedback. This is problematic because the potential risks specific to the transoral use of the da Vinci include tooth injury, mucosal laceration, ocular injury and mandibular fracture. To assess the potential for intraoperative injuries, we measured the load of the endoscope and the instrument of the da Vinci Si surgical system. We pressed the endoscope and instrument of the da Vinci Si against Load cell six times each and measured the dynamic load and the time-to-maximum load. We also struck the da Vinci Si endoscope and instrument against the Load cell six times each and measured the impact load. The maximum dynamic load was 7.27 ± 1.31 kg for the endoscope and 1.90 ± 0.72 for the instrument. The corresponding time-to-maximum loads were 1.72 ± 0.22 and 1.29 ± 0.34 s, but the impact loads were significantly lower than the dynamic load. It remains possible that a major load is exerted on adjacent structures by continuous contact with the endoscope and instrument of da Vinci Si. However, there is a minor delay in reaching the maximum load. Careful monitoring by an on-site assistant may, therefore, help prevent contiguous injury.

Mechanical evaluation of newly developed mouthpiece using polyethylene terephthalate glycol for transoral robotic surgery.

Transoral robotic surgery (TORS), performed with the da Vinci surgical system (da Vinci), has been classified as a surgical approach for benign and malignant lesions of the oral cavity and laryngopharynx. It provides several unique advantages, which include a three-dimensional magnified view, ability to see and work around curves or angles, and the availability of two or three robotic arms. At present, however, the da Vinci surgical system does not provide haptic feedback. The potential risks specific to the transoral use of the da Vinci include tooth injury, mucosal laceration, ocular injury, and mandibular fracture. To prevent such intra-operative tooth injuries, we created a mouthpiece made of polyethylene terephthalate glycol (PETG) individually shaped for the patient's teeth. We compared the safety and efficacy of the PETG mouthpiece with those of a conventional mouthpiece made of ethylene-vinyl acetate (EVA). To determine the difference in tooth injury resulting from the two types of mouthpiece, we constructed an experimental system to measure load and strain. We measured the dynamic load and the strain from the rod to the tooth using the PETG and EVA mouthpiece. The rod was pressed against the tooth model outfitted with two types of mouthpiece and the dynamic load was measured with a load cell and the strain with a strain gage. The maximum dynamic load was 1.29 ± 0.03 kgf for the PETG mouthpiece and 2.24 ± 0.05 kgf for the EVA mouthpiece. The load against the tooth was thus less for the EVA mouthpiece. The strain was -166.84 ± 3.94 and 48.24 ± 7.77 µÎµ, respectively, while the load direction was parallel to that of the tooth axis for the PETG mouthpiece and perpendicular to the tooth axis for the EVA mouthpiece. The PETG mouthpiece reduced the tooth load compared with the EVA mouthpiece and the load direction was in parallel to the tooth axis. The PETG mouthpiece thus enhances tooth safety for TORS.