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Introduction: To describe the technique, safety profile, and outcomes of performing pars plana vitrectomy (PPV) without intravenous (IV) anesthesia. Methods: This retrospective single-surgeon study comprised patients who had PPV without IV sedation between September 2018 and April 2022. Patients elected to undergo PPV without sedation or with oral sedation via sublingual triazolam administered 30 minutes preoperatively. Sub-Tenon bupivacaine and lidocaine were administered at the initiation of each case. A circulating nurse monitored patient vitals and electrocardiogram tracings without anesthesiologist support. Adverse events (AEs), visual acuity (VA), supplemental block administration, and reoperation rates were documented. Results: A total of 357 PPVs in 319 patients (mean age 68.75 ± 11.17 years [SD]; range, 36.82-98.57) were performed for surgical indications including vitreous floaters, intraocular lens or cataract surgery complications, retinal detachment, vitreous hemorrhage, and epiretinal membrane. Twenty-three cases were performed without sedation, and 334 were performed with oral sedation. For eyes with a follow-up longer than 1 month (n = 324), the preoperative VA of 0.68 ± 0.77 logMAR improved to 0.31 ± 0.46 logMAR postoperatively (P < .01). No intraoperative complications, systemic AEs, need to cease surgery prematurely, or conversion to IV sedation occurred. Five eyes (1.77%) required intraoperative supplemental sub-Tenon block administration, and 95% of patients who had a reoperation (n = 10) or fellow-eye surgery (n = 28) requested the same method of anesthesia without IV sedation. Conclusions: Vitreoretinal surgery with a sub-Tenon block and oral sedation can be safely performed without the support of an anesthesiologist. Additional trials are needed to further quantify patient comfort, surgeon experience, and complication rates.
RESUMO
Aberrant proteins can be deleterious to cells and are cleared by the ubiquitin-proteasome system. A group of C-end degrons that are recognized by specific cullin-RING ubiquitin E3 ligases (CRLs) has recently been identified in some of these abnormal polypeptides. Here, we report three crystal structures of a CRL2 substrate receptor, KLHDC2, in complex with the diglycine-ending C-end degrons of two early-terminated selenoproteins and the N-terminal proteolytic fragment of USP1. The E3 recognizes the degron peptides in a similarly coiled conformation and cradles their C-terminal diglycine with a deep surface pocket. By hydrogen bonding with multiple backbone carbonyls of the peptides, KLHDC2 further locks in the otherwise degenerate degrons with a compact interface and unexpected high affinities. Our results reveal the structural mechanism by which KLHDC2 recognizes the simplest C-end degron and suggest a functional necessity of the E3 to tightly maintain the low abundance of its select substrates.