Third window approach assisted middle meatal antrostomy: prospective cohort study of the two ports technique in management of hard to reach maxillary sinus pathology.

OBJECTIVE: This study aimed to assess the outcomes of a prelacrimal recess approach assisted middle meatal antrostomy in the management of hard to reach maxillary sinus pathologies. METHOD: Twenty-five patients with maxillary sinus pathology underwent prelacrimal recess approach assisted middle meatal antrostomy (with a prelacrimal recess width of more than 3 mm). Patients were prospectively evaluated using both the Arabic version of the Sino-Nasal Outcome Test-22 and nasal endoscopy at least 6 months post-operatively. RESULTS: Our study included 25 maxillary sinuses (13 with antrochoanal polyps, 10 with maxillary fungal ball and 2 with a migrated part of a tooth). At a mean follow-up period of 10.9 months, all patients showed significant improvement in total mean Sino-Nasal Outcome Test-22 score. There was recurrence of one case with antrochoanal polyp and two cases with asymptomatic synechia. Injury to the nasolacrimal duct was not reported. CONCLUSION: A prelacrimal recess approach assisted middle meatal antrostomy is a reliable and safe technique to manage pathologies in hard to reach regions within the maxillary sinus.

Scanning tunneling microscopy and surface simulation of zinc-blende GaN(001) intrinsic 4x reconstruction: linear gallium tetramers?

Scanning tunneling microscopy images confirm electron diffraction studies that the zinc-blende GaN(001)-4x reconstruction consists of rows aligned along [110] with a spacing along [110] of 4a. Dual-bias imaging shows a 180 degree shift of the corrugation maximum position between the profiles of empty and occupied states, in agreement with surface simulations based on the 4 x 1 linear tetramer model of Neugebauer et al. [Phys. Rev. Lett. 80, 3097 (1998)]. Electronic structure calculations predict a surface band gap of 1.1 eV, close to the measured value of 1.14 eV and the previously predicted value (1.2 eV). Despite the successes of this model, high-resolution images reveal an unexpected 3x periodicity (not seen in diffraction) along the [110] row direction, indicating the need for a 4 x 3 model, and putting into question the existence of linear Ga tetramers.