Histopathology of an explanted PTFE-lacrimal prosthesis

Abstract

In a 29-year-old man with complete posttraumatic obstruction of the lacrimal system a F'TFE-vascular graft was implanted, bypassing the completely scarred lacrimal pathway. Because any lacrimal mucosa was lacking, an interposition between conjunctiva and nasal mucosa was necessary. As GoreTex had been successfully used before in eyelid surgery and orbital surgery, the proven excellent biocompatibility of this material and the good results in vascular surgery were reason enough to use it in this very indication, where an epithelialization of the lumen was expected. The bypass was patent and well tolerated for 21/2 years before it had to be removed because of a therapy-refractive naso-cutaneous fistula.

The explanted material was examined by light and electron microscopy. Light microscopy showed an accumulation of inflammatory cells and fibrovascular tissue along the outside surface of the graft and there was an ingrowth of fibroblasts into the internodal spaces from both the outer and luminal surface. The intermediary zone was relatively acellular compared with the outer zones, this area being filled with a proteinaceous transudate. The tissue lining of the lumen revealed signs of both exudative and proliferative chronic inflammation. The smooth inner surface proved not to be covered by epithelial cells.

Electronmicroscopy showed numerous activated macrophages, the phagosomes containing amorphous material of different, partly fibrillary shape. The incorporated material is presumed to be degraded PTFE. As the expected epithelialization could not be achieved, the smooth inner fibrovascular tissue cover can obliterate after any inflammation. In view of the authors' findings, it is not further reasonable to utilize F'TFE-vascular grafts as lacrimal bypass.

Key Words:

• polytetrafluoroethylene vascular graft
• lacrimal prosthesis
• explantation
• histopathology
• lack of epithelialization