Is palato-premaxillary subduction a characteristic of Binder's syndrome?

Binder's syndrome is a rare malformative syndrome, defined clinically. CT study of a patient with this morphotype found palato-premaxillary joint subduction on a sagittal slice. The objective of the present study was to analyze this joint in a control population free of Binder's syndrome.

Fifty adult Caucasian patients who had undergone sinus CT scan between 2013 and 2016, showing normal nasolabial angle and with good visualization of the palato-premaxillary joint on a single sagittal slice, were selected. Joint analysis by 3 observers classified the patients in 2 groups: A, showing approximation between primary and secondary palate, and S, showing subduction. Alongside the observers' subjective analysis, the following parameters were compared: posterior palato-premaxillary angle (A₁), superior palato-premaxillary angle A₂, and the distance (d) of the premaxilla above the secondary palate.

Fifty patients were included: 43 in group A and 7 in group S. A₁ angle differed significantly between groups: 111.95±10.22° in group A, versus 130.53±10.0° in group S; P=0.0015. Values for A₂ and d did not differ according to group.

Two forms of palato-premaxillary joint, showing approximation or subduction, were found in the control population. Approximation was more frequent. Palato-premaxillary subduction does not in itself characterize Binder's syndrome.