Anatomic study for the horizontal cut of the sagittal split ramus osteotomy
Atson Carlos de Souza Fernandes1, Pauline Magalhães Cardoso, Itana Santos Fernandes
1Departamento de Ciências da Vida, Universidade do Estado da Bahia, Bahia, Brazil. atson@uneb.br
Summary
Point X on the mandibular ramus is a reliable reference for sagittal split ramus osteotomy (SSRO) cuts. The wider the ramus, the closer the cut should be to the mandibular foramen, not exceeding 4 mm above line X.
Area of Science:
- Anatomy
- Oral and Maxillofacial Surgery
- Surgical Anatomy
Background:
- Understanding the anatomy of the mandibular ramus is crucial for surgical procedures like sagittal split ramus osteotomy (SSRO).
- Accurate landmark identification is essential for safe and effective osteotomies.
Purpose of the Study:
- To determine the posterior extension of trabecular bone.
- To identify the merging point of lateral and medial cortical bone layers of the mandibular ramus using a reference point on the anterior margin.
Main Methods:
- Studied 80 adult human mandibles.
- Marked a line from anterior to posterior margin of the ramus on the medial aspect, starting at reference point X.
- Determined the merging levels of medial (H1) and lateral (H2) cortical bone layers on vertical sections and posterior trabecular bone extension on horizontal sections.
Main Results:
- Median values for H1 and H2 were 10.45 mm and 4.52 mm, respectively.
- H2 showed an inverse relationship with ramus width.
- Mean posterior extension of trabecular bone posterior to point Z was 17.17 mm, with no correlation to ramus width.
Conclusions:
- Reference point X is a safe and easily identifiable landmark for SSRO horizontal cuts.
- SSRO horizontal cuts should be positioned closer to the mandibular foramen in wider rami.
- SSRO horizontal cuts should not exceed 4 mm superior to line X; a definitive safe posterior limit could not be established.
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