# Facial soft tissue changes following isolated bilateral sagittal split osteotomy for mandibular advancement and setback, a review

## TL;DR

This review examines how facial soft tissues change after jaw surgery to move the lower jaw forward or backward.

## Contribution

The study systematically analyzes soft tissue outcomes following isolated BSSO procedures, highlighting variability and the need for standardized long-term studies.

## Key findings

- Soft-to-hard tissue ratios varied widely, with higher ratios observed for mandibular advancement.
- Long-term follow-up and 3D studies are needed to improve predictive models for soft tissue changes.
- Variability in outcomes is influenced by factors like skeletal relapse, age, and fixation type.

## Abstract

This review evaluated literature on soft tissue changes in patients following bilateral sagittal split osteotomy (BSSO) for mandibular advancement or setback. Twenty published articles were identified for further analysis. The included articles related to patient cohorts ranging between 12 and 109 participants, the age range of 14–68 years, with a majority of female patients, and follow-up periods in the range of 6–114 months. The primary outcomes were soft tissue changes in the cephalometric soft tissue points; pogonion (Pg'); menton (Me'); labrale inferius (Li); and mentolabial fold (B'). Soft-to-hard tissue ratios varied widely across both conventional and alternative mandibular procedures, with higher ratios observed for advancement in the conventional group. For example, at pogonion (Pg’) in advancement cases, ratios ranged from 80 – 133%. This study highlights the complexity of soft tissue changes following bilateral sagittal split osteotomy (BSSO). The variability seen in outcomes underscores the need for longer follow-up periods and surgery after skeletal growth has waned. Despite the valuable insights gained from the literature, considerable variability underscores the influence of skeletal relapse, age, and fixation type. Standardized long-term 3D studies are warranted to refine predictive models when isolated BSSO is performed.