An Endoscopic Approach for Frontal Sinus Cutaneous Fistula With Completely Ossified Frontal Recess.

A frontal sinus cutaneous fistula (FSCF) is a rare and challenging condition. Remarkable advancements in endonasal endoscopic surgery (EES) have enabled the treatment paradigm for a FSCF to gradually shift from open procedures to ESS. Nevertheless, the experience of EES for a post-trephination-related FSCF is rare, especially in patients with a pronounced frontal recess (FR) ossification. Here, we report an endoscopic strategy for successfully treating a post-trephination-related FSCF with complete ipsilateral FR neo-osteogenesis. Through two surgical corridors created by the modified mini-Lothrop procedure and an ipsilateral frontal osteotomy window, we established a patent drainage pathway from the affected side to the opposite side. This strategy may prevent potential orbital and cranial base injuries from affecting the ossified region of the ipsilateral FR. Moreover, in addition to the advantage of aesthetic outcomes, the procedure allows a single-stage surgery and facilitates the debridement and surveillance of the wound through the drainage pathway postoperatively. In conclusion, this technique could be a feasible endoscopic strategy for a FSCF, regardless of the severity of the FR ossification.

Fluorescence depletion properties of insulin-gold nanoclusters.

Insulin-gold nanoclusters exhibit outstanding biocompatibility, photostability, and fluorescence quantum efficiency. However, they have never been used in superresolution microscopy, which requires nonlinear switching or saturation of fluorescence. Here we examine the fluorescence and stimulated emission depletion properties of gold nanoclusters. Their bleaching rate is very slow, demonstrating superior photostability. Surprisingly, however, the best depletion efficiency is less than 70%, whereas the depletion intensity requirement is much higher than the expectation from a simple two-level model. Fluorescence lifetime measurement revealed two distinct lifetime components, which indicate intersystem and reverse intersystem crossing during excitation. Based on population dynamic calculation, excellent agreement of the maximal depletion efficiency is found. Our work not only features the first examination of STED with metallic clusters, but also reveals the significance of molecular transition dynamics when considering a STED labeling.