Glial cells of the human fovea.

Purpose: The exact cellular types that form the human fovea remain a subject of debate, and few studies have been conducted on human macula to solve this question. The purpose of this study was to perform immunohistochemistry on fresh human samples to characterize the glial cells that form the human fovea. Methods: Immunohistochemistry was performed using antibodies against proteins expressed in astrocytes or in retinal Müller glial cells or both types of cells on six human macula obtained from eyes enucleated for peripheral intraocular tumors and on two postmortem eyes from healthy donors. The posterior poles of the enucleated eyes were cryosectioned and stained with antibodies against the glial proteins GFAP, vimentin, CRALBP, glutamine synthetase, and connexin 43. Results: A population of cells positive for GFAP and negative for glutamine synthetase and CRALBP that express connexin 43 were identified at the roof of the foveal pit. These cells are distinct from the Müller cone cells described by Yamada and Gass, suggesting that another type of foveal glial cells, most likely astrocytes, are present in the human fovea. Conclusions: This study showed that in humans, astrocytic glial cells cover the foveal pit. Their roles in macula homeostasis and mechanisms of macular diseases disease remain to be determined.

Loss of neuromonitoring signal during bilateral thyroidectomy: no systematic change in operative strategy according to a survey of the French Association of Endocrine Surgeons (AFCE).

BACKGROUND: Total thyroidectomy presents a risk of bilateral vocal cord paralysis, which can lead to compromised airway. Visual Recurrent Laryngeal Nerve (RLN) identification significantly decreases this risk of RLN lesion. Yet, an anatomically intact nerve is not always functional. Intraoperative neuromonitoring (IONM) allows to test in real time the function of the RLN. In case of loss of signal (LOS) on the first operated side, some authors recommend to stop the intervention. The purpose of this study was to characterize the operative strategy of the French-speaking surgeons in case of LOS on the first side in planned bilateral thyroidectomies. METHODS: An online questionnaire was sent to the surgeons of the French Association of Endocrine Surgeons (AFCE). RESULTS: We collected 69 responses (response rate: 42%). Forty-six surgeons (66%) used IONM. After a signal loss, 22% (N = 10) stopped the operation in all cases, 24% (N = 11) continued the operation in case of malignant disease and stopped in cases of benign disease, and 54% (N = 25) continued the operation contralaterally. CONCLUSIONS: The majority of surgeons continued the operation contralaterally as originally planned despite a loss of IONM signal at the end of the first side.