3. Contraindications of BSSO
• Severe decreased posterior mandibular body
height
• Extremely thin medial lateral width of the
ramus
• Severe ramus hypoplasia
• Severe asymmetries
4. Advantages of BSSO
1) Quick healing because of good bony interface
therefore predictible bony union
2) Surgery can advance or set back the
mandible ,correct most asymmetries and
alter the occlusal plane
3) Rigid Fixation can be used eliminating the
need for MMF allowing early mobilisation of
mandible and easier management of the
airway
5. Advantages of BSSO
4) Modifications can maintain the angle of
mandible in the original spatial position even
in large advancement
5) Major muscles of mastication remain in
original position
6) It has good stability
6. DISADVANTAGES
• Incidence of nerve damage increased i.e
Inferior alveolar nerve damagealtered
sensation of lower lip
• Unfavorable splits may occur
• Surgery must create a fracture on the lingual
aspect of the ramus
• Significant asymmetries are difficult to
corrrect
8. procedure
• 1) G.A AND L.A
• 2) Incision
• 3) Subperiosteal dissection and flap elevation
• 4) Bone cutting
• 5) Bone spliting
• 6) Mandibular repositioning
• 7) Excess bone removal
• 8) Rigid Fixation
• 9) Wound closure
9. Corticotomies
• The procedure starts with three corticotomies.
• The first cut is made through the lingual cortex
just above the mandibular foramen parallel to
the occlusion. The corticotomy is extended
from the anterior border of the ramus to just
behind the entrance of the inferior alveolar
canal (lingula).
11. Second cut
• The second corticotomy is made through the
buccal cortex in a vertical direction at the level
of the first or second molar.
12. Third corticotomy
• The third corticotomy connects the first two
osteotomy lines along the anterior border of
the ascending ramus.
13. The sagittal split
• The final split is completed with a thin
osteotome, splitting the entire ascending
ramus from the anterior to the posterior
border of the ramus.
14.
15. Steps of BSSO
• The surgical technique of the sagittal split
mandibular ramus osteotomy can be
performed in 32 steps
• Step 1:infiltrate the soft tissue with
vasoconstrictor
• Step 2: the soft tissue incision
• Step 3:buccal subperiosteal dissection
• Step 4: superior subperiosteal dissection
16. BSSO STEPS
• Step 5:exposure of the lingula
• Step 6:medial ramus osteotomy
• Step 7:sagittal osteotomy
• Step 8: buccal osteotomy of the mandibular
body
• Step 9: drill holes for a holding wire
• Step 10:drill a hole for the condylar positioner
17. BSSO STEPS
• Step 11: place reference marks
• Step 12: lavage
• Step 13: define the osteotomy
• Step 14:splitting the mandible
• Step 15:stripping the pterygomasseteric sling
• Step 16:stripping the medial pterygoid muscle
and stylomandibular ligament
• Step 17: third molars removal
18. BSSO STEPS
• Step 18:smooth the contact areas of the
segments
• Step 19: place the holding wire
• Step 20
Note the position of the inferior alveolar
neurovascular bundle and the socket of the
third molar (if a tooth was present and
removed)
• Step 21:mobilize the bone segments
19. BSSO STEPS
• Step 22:place the teeth into the planned
occlusion
• Step 23:remove bone from the proximal
segment in class III mandibular setback cases
• Step 24: positioning the condyle
• Step 25: tightening the holding wires
• Step 26:placement of the trocar
• Step 27: drill the holes and for the place of rigid
fixation
20. BSSO Steps
• Step 28:remove the intermaxillary fixation and
check the occlusion
• Step 29: intraoperative diagnosis of a
malocclusion
• Step 30: place intra and extraoral sutures
• Step 31: place intermaxillary elastics
• Step 32: Apply a pressure bandage
22. A large pear-shaped vulcanite drill is used to reduce the
bone and increase the visibility of the lingula.
23. A) The completed sagittal osteotomy is demonstrated (arrow 1). Start the buccal osteotomy at the inferior
border and connect it to the vertical osteotomy (arrow 2). (B) The buccal osteotomy is completed in a slight
posterior medial direction to facilitate the introduction of the Reyneke splitting osteotome and to initiate
and direct the split in the proper direction.
25. A Reyneke splitter is placed into the buccal osteotomy on the lower border of the mandible (1).
The splitter and an osteotome, placed into the superior aspect of the vertical osteotomy, are
gently rotated (1 & 2). The lower border should separate from the distal segment including the
lower border of the mandible (3)
26. The 4 typical fracture lines of bad splits are demonstrated: buccal plate fracture (1),
buccal plate fracture including the coronoid process (2), a fracture short of the lingula
(3), and a retromolar fracture (4).
buccal plate
fracture
buccal plate fracture
including the coronoid
process
a fracture short o
the lingula
retromolar
fracture
27. The pterygoid muscle and stylomandibular ligament is stripped off the medial aspect
of the mandibular angle
28. Positioning of the
condyle
. Posterior pressure on
the positioning instrument
(1) and extraoral digital
pressure on the angle of
the mandible pushing
superiorly and slightly
anteriorly (2) will give the
surgeon control of the
proximal segment (3).
Once the surgeon is
confident that the
condyle is positioned
correctly in the fossa, the
assistant can tighten the
positioning wire (4).
29. REMOVAL OF POSITIONING
WIRE
The positioning wire may
be removed at this stage;
however, it is optional, and
it may serve as additional
fixation (1). The reference
lines allow for adequate
alignment of the segments
(2). Three bicortical screws
are demonstrated as
internal rigid fixation (3).
