BSSO VRO COMPLICATIONS

1. Complications of Mandibular
Orthognathic surgery
Dr Jameel Kifayatullah
Oral and maxillofacial surgeon
Khyber College of dentistry Peshawar

2. complications
Intraoperative complications
Nerve Injuries
Hemorrhage
Dental and periodontal injuries
Bad Splits
Displacement of Proximal VRO segment

3. Complications
Postoperative
Avascular necrosis
Non Union Mandible
Proximal segment rotation
TMJ EFFECTS
Condylar resorption
Relapse
Freys syndrome

4. Causes of nerve injury in Orthognathic
surgery
• Unfavorable fractures
• Aggressive retraction
• Hemorrhage
• Hematoma formation
• Postoperative edema (Indirect trauma)
• Direct trauma with surgical instruments
• Stretching during manipulation of
osteotomised segments

5. Risks of nerve injury
• Patients age at time of surgery(older than 40
years increased risk esp in BSSO)
• Length of surgery
• Type of
procedures(LefortI,BSSO,BIVRO/genioplasty)
• Skill of surgeon
• Magnitude of segment advancement
• Patients anatomy
• Course of nerve

6. SSO(Sagittal split osteotomy)
• Most common sensory nerve injury with BSSO
occurs to Inferior alveolar nerve as it courses
through mandibular canal
• Incidence of transection: 2-3.5%

7. Factors predisposing a patient to IAN
injury
• AGE
• THE MAGNITUDE OF
MANDIBULAR
MOVEMENT
• POSITION OF INFERIOR
ALVEOLAR NERVE
• CONCOMITANT
GENIOPLASTY
• THE SURGEONS SKILLS
• DEGREE OF
MANIPULATION OF IAN

8. Event at which inferior alveolar nerve
injury occurs
• Injury to the Inferior alveolar nerve can occur
while performing a BSSO during the
dissection, retraction, osteotomy , segment
mobilization, or hardware application.

9. RISK
• Reported risk of long term IAN deficit after
BSSO=0-75%

10. Transection of inferior alveolar nerve
• 3.5% incidence of IAN transection anterior to
or in third molar region
• IAN is the most lateral and buccal cortex of
mandible is thinnest in this location so
vulnerable to injury

11. Transection Of Inferior alveolar nerve
• Intraoperative transection of nerve best
treated by immediate epineurial repair with
non absorbable 6-0 to 8-0 monofilament
nylon sutures

12. Transection of Inferior alveolar nerve
• Transection at vertical bony cut SSO:
Immediate repair difficult
• Expose more of the nerve in the distal
segment to allow a tension free repair

13. How to prevent Injuries to IAN
• Evaluate the position of
the nerve and plan
mandibular
osteotomies accordingly
• EVALUATION by CBCT
and OPG

14. How to prevent Injuries to IAN
TECHNIQUES SUGGESTED TO PREVENT IAN
INJURIES
• Varying the osteotomy design
• Cautious chisel placement
• Meticulous dissection technique
• Decompression of lateral fragments if
indicated
• Perioperative steroid use

15. How to prevent injuries to IAN
• Retraction on the medial aspect of mandible
done carefully to avoid compression nerve
injuries
• IDEAL LOCATION TO CREATE VERTICAL
(BUCCAL) CUT: First and Second molar region
where the cortex is thickest and nerve is
farthest from lateral cortex

16. How to prevent damage to IAN
• After subperiosteal dissection on medial side
of mandible tenting the lingual periosteum at
the mandibular foramen with seldin retractor
to protect IAN
• The anterior vertical osteotomy of SSO should
be stopped as soon as cut is through the
buccal cortex (indicated by bleeding from
cancellous bone)

17. How to prevent Injury to IAN
Splitting: if it is noted
that nerve is embedded
in the proximal
segment(buccal cortex)
during the split
unroofing of the medial
wall of the canal with
fine ostetomes
/periosteal elevator
done to deliver the
nerve away from buccal
cortex
neurovascular bundle remains attached to the
proximal segment of the mandible. b A freer or
a nerve hook-type instrument is used to free
nerve from bone. c An osteotome is used to
free nerve from bone

18. How to prevent nerve injury
Screws placement:
Non compressional
positional screws
should be placed at the
superior border of
osteotomy during rigid
internal fixation to
prevent IAN
compression injury
from placement of
compression screws.

19. Lingual nerve injury
• High injury rates of 9-
19% have been
reported

20. Prevention of lingual injury
• Careful application of local anaesthesia
• Appropriate placement of initial mucosa
incision
• Creful subperiosteal dissection of the lingual
tissue especially in third molars area.
• Avoid placement of excessively long bicortical
screws on the superior border of the mandible
for osteosynthesis.Use 15 mm screws or
monocortical screws or place plates.

21. prevention

22. Prevention and management of
lingual nerve injury
• Placement of long screws result in painful
dysesthesia when patient eats and speaks.
• Re-operation and removal of screws and
replacement with appropriate length screws
may be necessary

23. Prevention and management of lingual
nerve injury
• Hematoma after severe bleeding on the inner
side of the mandible exert pressure on lingual
nerve and cause temporary paresthesia of the
tongue
• Sensory defects and loss of taste
• Spontaneous resolution
• Extensive hematoma should be drained to
achieve rapid recovery
• Recovery within a few weeks

24. NERVE INJURY IN Vertical Ramus
Osteotomy(VRO)
• Risk of neurosensory
deficit significantly less
when compared to
BSSO
• 2.3-14% risk

25. Prevention of nerve injury in VRO
• Antilingula (bulge on
lateral surface of ramus
corresponding to lingula
position on medial side)
identified and creation
of osteotomy with saw
blade 5 mm posterior to
bulge of antilingula on
lateral surface of
mandible.

26. Prevention of nerve injury in VRO
• Release all the muscular and periosteal
attachments from the medial inferior surface
of proximal segment so that proximal segment
sit passsively lateral to distal segment.
• This avoids medial displacement of proximal
segment and impingement of Inferior alveolar
nerve and paresthesia.

27. Genioplasty
• Mental nerve is at risk
of injury
• Incidence of sensory
loss= 20%
• Genioplasty incision
should be made
through mucosa b/w
the mandibular canines
to prevent injury to the
branches of mental
nerve

28. Genioplasty and prevention of nerve
injury
• Genioplasty osteotomy
made 5 mm below the
mental foramen to
prevent injury to the
anterior loop of the
mental nerve

29. Hemorrhage
Vessels most commonly
injured in mandibular
orthognathic surgery
internal maxillary artery
facial artery
inferior alveolar artery
masseteric artery
retromandibular vein
pterygoid plexus

30. HEMORRHAGE
Cause
• Inexperience
• Excessive soft tissue stripping
• Dissection

31. Prevention of hemorrhage
• Intraoperative serious
hemorrhage : a rare
complication during a
BSSO.
• Maintaining the surgical
dissection subperiosteally
and adequate retraction
of soft tissue prevent
minor intraoperative
oozing and most cases of
major hemorrhage
(adequate placement of
retrctors)

32. Methods of controlling bleeding
Minor hemorrhage from tearing of the
periosteum can be controlled with:
• Gauze packing
• Electrocautery
• Clamping with hemostats or hemoclips if
severed vessel identified
• Injecting epinephrine (1;100,000 or 1;50,000)
into vessel walls

33. Methods of controlling bleeding

34. Bleeding from maxillary artery
• Carotid artery ligation
• Angiography and embolisation

35. Embolisation of internal maxillary
artery

36. Avascular Necrosis
Avascular necrosis of proximal segment rare
after BSSO
Cause: excessive stripping of the segments

37. AVASCULAR NECROSIS
Avascular necrosis minimised by
1) Modification of SSO technique in which
amount of lateral dissection of masseter
muscle and associated periosteum greatly
decreased
2) Rigid fixation of bony segments permits early
revascularisation and prevent segment
mobility minimising the incidence of
avascular necrosis in mandible

38. AVASCULAR NECROSIS
• Intraoral vertical subcondylar osteotomy
:proximal segment is at most risk of vascular
necrosis due to wide release of periosteal
attachments
• Technique modified in which soft tissue
pedicle of medial pterygoid muscle attached
to posterior and medial aspect of proximal
segment maintained : aseptic necrosis
minimised

39. Non Union Mandible
Causes
avascular necrosis
Insufficient bone contact
Instability of fixtion devices
Instability of bone fragments

40. Non union mandible
• Large BSSO advancements greater than 7 mm
require additional fixation inorder to maintain
stability and prevent non union
e.g rigid plates and skeletal suspension wires
Delayed union SSO mandible: tx with a short
period of IMF or A Second operation in which
additional plates and screws are applied for
stability

41. Non Union Mandible
• NON UNION VERTICAL
SUBCONDYLAR
OSTEOTOMY (VRO):
Second operation
needed ;extraoral
approach to access
proximal segment
,properly align and
apply rigid fixation.

42. Dental and periodontal injuries
• More common with segmental procedures
and interdental osteotomies.
• Problems encountered with segmental
porcedures: Injury to tooth roots,Tooth loss,
need for postoperative Root canal therapy,
development of significant periodontal defects

43. Dental and periodontal defects
• Sufficient space
between the teeth for
interdental osteotomies
must be ensured with
pre operative
orthodontic mechanics
with coils.
• A minimum of 3 mm is
advocted between
teeth for interdental
osteotomies

44. Dental and periodontal defects
• Interdental osteotomy should be made using
fine osteotomes to prevent damage to the
teeth

45. Dental and periodontal injuries
• a minimum of 5 mm
space is recommended
for subapical
osteotomies above root
apices to avoid injury to
dental branches of
nerves.

46. BAD SPLITS
• An unfavourable and unanticipated pattern of
the mandibular osteotomy fracture is
generally referred to as a ‘bad split’

47. Causes and risk factors of bad splits
• Lack of cancellous bone between the two cortical
bone layers in ascending ramus makes the split more
difficult and hinders exact separation of cortical and
cancellous bone.
• inadequate vertical osteotomy at the inferior border
• horizontal osteotomy performed too high above the lingula
• exertion of excess force when separating the proximal and
distal segments
• impacted third molars.
There is much controversy among scholars regarding
whether impacted teeth should be extracted 6-9 months
before SSRO or at the same time as SSRO.

48. CONSEQUENCES OF BAD SPLIT
Bad splits may cause
• mechanical instability,
• a disturbance in bony union
• lead to bone sequestration with subsequent
infection

49. BAD SPLITS
Fracture of buccal
cortex
Fracture of coronoid
process
Fracture of condylar
process

50. Prevention of bad splits
Prevention is focussed on
• adequate osteotomy design,
• eliminating sharp angle where abnormal
stress occurs on bony segments
• completion of adequate cuts into the
retrolingular depression and through the
inferior border
• careful separation of the segment.

51. Management of bad splits
If a fracture occurs,
• fractured segments should be reconsolidated if
possible.
• The segments should be rigidly fixated whenever
possible providing stable continuity between the
most proximal portion of the mandible and the
distal segment.
• Fractured segments should be incorporated into
the fixation scheme to avoid unfavorable post
surgical positional changes.
• In some cases grafting may be required.

52. Guiding oblique cut BSSO
• (a) Anterior half cut
running parallel to
occlusal plane (colored
line); (b) posterior half cut
(guiding oblique (GO) cut)
with an angulation of "θ"
running obliquely
downwards and ending in
lingual fossa; (c) favorable
lingual split directed
towards inferior body
osteotomy by GO cut

53. Displacement of Proximal VRO
Segment
• Excessive lateral
displacement of proximal
segment occur during
VRO
• Excessive flaring of
proximal segment by
premature contact at
sigmoid region
• Corrected by bone wedge
removal from distal
segment wider at the
sigmoid region than at
the inferior border

54. Proximal segment Rotation
• Lack of control of
proximal segment with
an SSO can have clinical
effects with both
aesthetic and functional
consequences.

55. Proximal segment Rotation
• Anterior and superior counter
clockwise rotation of the
proximal segment after SSO by
pull of temporalis and
masseter muscles.
• Clockwise rotation of distal
segment after SSO by pull of
mylohyoid
,geniohyoid,genioglossus
,suprahyoid muscles
EFFECT
The result is unaesthetic cosmetic
result with flattening of gonial
angle and notching in
anteogonial notch region

56. Proximal segment rotation
PREVENTION
Prevention by use of
positioning appliances
to control the proximal
segment during
mandibular
orthognathic surgery

57. Proximal segment rotation
• Excessive rotation of
proximal segment
causes the following
problems which needs
to be assessed:
• 1) FUNCTIONAL:
decreased bite force
generation or
hypomobility
• 2) AESTHETIC: loss of
gonial angle

58. Proximal segment rotation
• An aesthetic problem in a
patient with acceptable occlusal
result: use an alloplastic
implant(porous polyethylene)
• Occlusal problem + esthetic
concern=revise the SSO with
surgery
• Malocclusion and unaesthetic
result combined with decrease
in bite force/hypomobility of
mandible= REOPERATION with
application of rigid fixation
combined with aggressive
postoperative physiotherapy.

59. TMJ EFFECTS
• There is still controversy about whether
orthognathic surgery negatively or positively
affects temporomandibular disorders (TMDs)
• Orthognathic surgery caused a decrease in
TMD symptoms for many patients who had
symptoms before surgery, but it created
symptoms in a smaller group of patients who
were asymptomatic before surgery

60. CONDYLAR RESORPTION
Incidence ranges from 5-10% of the patients who
undergo orthognathic surgery
Skeletal predisposing factors for condylar resorption
High mandibular plane angle
Condyle with posterior inclination
low posterior to anterior face height ratio
Contributing skeletal factors
counterclockwise rotation of the proximal segment
preoperative TMJ dysfunction
Patients requiring a large magnitude advancement
of mandible
vascular necrosis of the condyle as a
consequence of traumatic stress during surgery

61. Condylar resorption
Prevention
Proper positioning of the proximal segment
into the fossa after splitting the mandible is of
utmost importance to avoid postoperative
TMJ problems including condylar resorption

62. Condylar resorption
Management
Splint therapy
antiinflammatory medications
open joint surgery with synovectomy to
aggressively address the synovial
inflammation and halt the progression of
condylar resorption (advocated by some
surgeons)

63. RELAPSE/INSTABILITY AFTER
ORTHOGNATHIC SURGERY
• Relapse is defined as return toward the
original position
• Instability is defined as a postoperative
movement either toward the preopertive
position or further away from it

64. Factors influencing relapse
• Soft tissue and muscle
tension
• orofacial habits
• the type of fixation
• the magnitude and type
of mandibular
movement
• the position of the
proximal segment
• disc displacement
• Low and high
mandibular plane angle
• Remaining growth and
remodeling
• Preoperative age of
patients
• Surgeon skills
• Condylar position
within glenoid fossa
• Condylar sag

65. Management of Relapse
Managed according to identified cause
• Condylar positional discrepencies
Result: Anterior or posterior open bite
Lateral shifts of the occusion
Severe occlusal discrepancies:revision of
orthognathic procedure
Minor occlusal discrepancies: early aggressive
orthodontics with orthopedic movement of the
bony segments and teeth.

66. Management of relapse
• Posterior open bite<3 mm : tx with vertical
elastics or other orthodontic mechanics
• Failure to properly place the condyle in the
glenoid fossa or instability at the osteotomy
site with loss of fixation :The result is anterior
open bite
• Instability at osteotomy site: use of IMF with
heavy elastic traction
• Condylar malpositioning: revision surgery

67. Management of Relapse
• Relapse of skeletal class III mandibular
setback:seen with larger degrees of posterior
mandibular movement
• Caused by pushing the proximal segment back
during surgery especially in IVRO .With the
release of IMF the mandible rotates forward
• Prevention : align the inferior borders of proximal
and distal segments and release the medial
pterygoid muscle to allow passive fit of segments

68. Management of relapse
Occlusal discrepancy after SSO
• Short term use of Class III elastics help to
correct the problem(1-2 mm discrepancy)
• Occlusal discrepancy greater than 3-4 mm
orthodontic mechanics/interproximal
reduction/second revision surgery

69. Management of relapse
• Anterior open bite after
intraoral VRO upon release of
IMF
Correction with removal of
coronoid process
and temporalis muscle
influence
use of skeletal suspension wires
for additional fixation
using modified osteotomy cuts
of the ramus to maximise bony
contacts
Extending postoperative IMF
period to atleast 8 weeks

71. Auriculotemporal syndrome
• Freys syndrome may occur
after extraoral vertical ramus
osteotomies and bilateral
sagittal split osteotomies
• MECHNISM: After an injury to
the auriculotemporal nerve,
the symptoms are believed to
be caused by a misdirected
regeneration of
parasympathetic fibers to
denervated sweat glands.
• Patients’ symptoms occurred 3
months to 3 years after
surgery.

72. Freys syndrome mechnism in
orthognathic surgery
• In this case, we can presume the possibility that surgical damage
occur in the region of the parotid gland during orthognathic
surgery.
• As one of the three salivary glands, the parotid gland wraps the
back side of mandible ramus and stretches from the anterior part of
the earhole through the cheek to the lower part of the mandible
angle.
• Glosspharyngeal nerves together with parasympathetic nerves
synapse in the otic ganglion and dominate the parotid gland
through glosspharyngeal nerves.
• That is, mandible might possibly have moved backward and pressed
the parotid gland or osteotome might possibly have been pushed
backward and damaged the parotid gland intra-procedurally.

74. FREYS SYNDROME
• Patients complain of
redness and sweating of
the skin in the surgical
field during meals
caused by misdirected
parasympathic fibers,
resulting in the
sympathetically
driven vasomotor effect
of sweating and flushing
of the skin.

75. FREYS SYNDROME
• Topical
application of scopolam
ine gel (1% to 3%)
or aluminium chloride
hexahydrate gel may be
helpful.
• There is clear evidence
for a successful the
treatment of Frey
syndrome
with botulinum toxin A

76. FREYS SYNDROME

77. RICHARD TRAUNER(1900-1980)

78. HUGO OBWEGESER 1920-2017