LASIK Surgical Smoke Analysis by MALDI Indicates Presence of Polypeptides

Abstract

Abstract: : Purpose: LASIK is the most widely performed refractive surgical procedure. Surgical smoke inhalation is a health concern to refractive surgeons and researchers. The present theory of laser photochemical ablation suggests that only small terminal degradation products would be present in the plume. Preliminary data from amino acid analysis and gel electrophoresis indicated the presence of proteinaceous material of up to 5 kDa molecular weight. (Glickman et al, Proc. SPIE v. 4951:124–32, 2003). Peptides of this size are sufficient to provoke allergenic reactions, and thus pose allergeneic risk to those exposed to those exposed to surgical smoke produced during LASIK. The purpose of this study was to refine the analysis of biomolecules in the excimer induced plume. Methods: A Mastel clean room smoke evacuation unit was used with a LADARVISION excimer laser. The Mastel filters were used to trap the plume particles produced during LASIK procedures. Unused filters were used as a control. The PTFE filter elements were removed from the plastic housings in a negative pressure fume hood and stored at –70C until analysis. Material trapped on the filter was eluted with successive washes of 50% and 90% acetonitrile (ACN) with 1% TFA. The extracted material was concentrated by evaporation of the ACN prior to analysis with MALDI mass spectroscopy. Results: Previous analysis indicated that amino acids were present as oligopeptides. This was consistent with MALDI analysis which indicated randomly fragmented polypeptides in the range of 600 to 2000 m/z were present only on the patient–exposed filters. The randomly fragmented nature of the peptides precluded identification of the parent protein(s). Conclusions: Results to date suggest that polypeptides are present in the LASIK plume with masses consistent with the range identified in our previous analysis. The presence of these large molecules is not predicted by the current theory of excimer laser photochemical ablation. We hypothesize that local thermal reactions may cause fragmentation and ejection of polypeptides. Regardless of the mechanism of fragmentation, the present findings underscore the biohazardous nature of the LASIK plume and the need for efficient smoke evacuation during these procedures.

Keywords: cornea: basic science