Vertical Changes Associated with 3D-Guided Midpalatal Piezocorticotomy - Assisted MARPE in Adults: A Retrospective Cohort Study

Introduction. The success rate of 3D- Guided Midpalatal Piezocorticotomy -Assisted MARPE (3D-GMP MARPE) has significantly improved outcomes for adults seeking skeletal midfacial expansion. Besides providing a predictable outcome of midpalatal suture separation, this method has eliminated age and sex as two factors that were reportedly considered limiting in the past. Nevertheless, there is a residual concern regarding potential maxillary downward rotation linked to increase in anterior and posterior facial height. The hypothesis of the study was that two groups with different pre-existing maxillary base rotation would demonstrate varying post-treatment changes. Methods. The current study evaluated 80 adult patients aged 35.23 ± 8.76 years who underwent 3D-GMP MARPE. The study sample was divided into two groups which were compared based on the pre-existing downward maxillary plane rotation. Group 1 consisted of 65 subjects without pre-existing downward maxillary rotation while Group 2 included 15 subjects with pre-existing downward maxillary rotation. Results. Group 1 and Group 2 showed significant differences in SNMP angle, U1MP angle, and LAFH change with the procedure. SNMP (mean = 1.8 degrees, 95% CI [0.78, 2.82]) and U1MP (mean 3.95 degrees, 95% CI [1.83,6.06] ) angles significantly increased with the procedure in Group 2. LAFH (mean -2.13 mm, 95% CI [-3.81, -.95]) significantly decreased with intervention in Group 2. The crude analysis demonstrated a 395% risk (95% CI [2.13, 11.53]) of developing downward maxillary rotation in the group with pre-existing downward maxillary rotation. The odds of developing downward rotation in the exposed group is 9.47 (95% CI [2.63,34.13]) times higher than in the group without downward rotation. Conclusions. The odds of developing post-procedure downward maxillary rotation is 9.47 times higher in patients with pre-existing downward rotation. Lower anterior facial height was shown to decrease with intervention in the group with pre-existing downward maxillary rotation, while the upper incisor inclination and SNMP angle increase in this group.