Measuring the Change in Soft Palate Length and Shape Following Maxillary Advancement: A Cohort Study in Patients with Orofacial Clefts.

Objective: To evaluate a method of measuring the change in palatal length and shape following maxillary advancement using synchronous lateral videofluoroscopy and voice recording in order to understand how movement of the maxilla may affect VPI risk in patients with cleft lip and/or palate (CL/P).

Design: Retrospective cohort study of children with cleft lip and/or palate.

Setting: Single center, tertiary children's hospital.

Participants: Patients with cleft lip and/or palate who underwent maxillary advancement between 2016-21 inclusive.

Interventions: Maxillary advancement surgery, including those who underwent concurrent mandibular procedures.

Main outcome measures: The length of the soft palate and the genu angle were measured throughout palatal dynamic range. Pre- and post-operative measurements were compared using a one sided T-test, with subgroup analysis for patients with clinical VPI.

Results: Ten patients were examined. The mean distance of maxillary advancement was 10.5 mm. The average increase in pre-genu soft palate length was 2.8 mm in the resting position and 2.9 mm in the closed position. The genu angle decreased in the closed position by 16.3 degrees.

Conclusions: The soft palate showed limited ability to lengthen following maxillary advancement and this may explain the risk of VPI. There was partial compensation by the muscle sling of the palate as demonstrated by a more acute post-operative genu angle and this suggests one reason for the variability of VPI reported. Future research is required to investigate how length and shape changes measured using this method can predict VPI risk.