Fracture
of mandible during yawning in a patient with
osteogenesis imperfecta
Ram H, Shadab M, Vardaan A, Aga P.
Department of Oral and
Maxillofacial Surgery, King George's Medical
University, Lucknow, Uttar Pradesh,
India
Abstract
Osteogenesis imperfecta is a genetic
disorder characterised by fragility and multiple
fractures of bones. Clinical signs and symptoms
vary depending on the type of disease. Fractures
of facial bones are rare compared with
load-bearing long bones. We report a case of
fracture of the mandible during yawning which
was managed by open reduction and internal
fixation.
BACKGROUND
Osteogenesis imperfecta (OI) is a rarely
seen syndrome characterised by fragility of
bone. It is also known as brittle bone disease.
OI is a genetic disorder of connective tissue
resulting from mutations in the gene COL1A1 on
chromosome 17 and gene COL1A2 on chromosome 7,
which encode the synthesis of two pro-1 chains
and pro-2 chains of type I collagen. Abnormal
matrix is produced by osteoblasts which does not
bear an adequate mechanical load. Bone, dentin,
sclera and ligaments have abundant type I
collagen, so these structures are most commonly
affected. The incidence of OI ranges from 1 : 10
000 to 1 : 20 000 births. On the basis of
clinical criteria, Sillence classified OI into
four types, and further types V, VI and VII were
added by Glorieux et al and Ward et al. The
Sillence classification remains the most
commonly used.
Patients with OI have multiple bone
fractures, most commonly of the extremities and
especially the lower extremity which is exposed
to the maximum body load. Facial fractures are
not frequently seen but may occur during
extraction of teeth. Facial bones may also
fracture during yawning or mastication of hard
objects due to high muscular forces. Extraction
of teeth in patients with OI is avoided because
there is an increased chance of developing
osteoradionecrosis.14 Bisphosphonates are used
for the treatment of OI. Fracture of facial
bones can be treated by either open or closed
reduction, depending on the indications.
CASE PRESENTATION
A 35-year-old man presented to the
Department of Oral and Maxillofacial Surgery
with pain during mastication and a sudden
increase in pain during a yawning episode. An
extraoral examination showed slight swelling on
the left side of the face. On palpation,
tenderness was noted at the angle and ramus
region of the mandible. Intraoral examination
revealed poor oral hygiene. There was a history
of spontaneous shedding of maxillary right
premolars and molars. The mandibular left
premolars and molars were also absent. The upper
first maxillary molar was deformed and bulbous
and other molar teeth were also deformed. A deep
fissure was present at the midline of the
palate. Occlusion was deranged and the patient
was unable to close his mouth properly General
examination of the patient revealed a short
stature of about 4 feet. There was deformity and
severe bowing of the legs due to spontaneous
Osteopenia was present with multiple fractures
in different healing phases in the clavicles,
ribs, scapula, bilateral radius and right ulna,
right and left tibia and fibula and right femur,
some showing exuberant callus and
pseudoarthrosis
The family history revealed that a younger
brother of the patient had OI and had died 14
years previously at the age of 22 years. One
brother and five sisters were normal. The
personal history revealed that the patient was a
chronic smoker and took 20 cigarettes per day
for the last 10 years.
DISCUSSION
Multiple fractures of extremities are common
in patients with OI. Deformity and bowing of the
long bones are most frequently seen in these
patients. Deafness, short stature, blue sclera,
joint laxity, kyphosis, scoliosis, pigeon-shaped
chest and Wormian bones of the skull may also be
seen. Associated dental symptoms may occur with
dentinogenesis imperfecta, grey-brown or yellow
brittle teeth and bulky crown and malocclusion.
This patient was of short stature with severe
bowing of the legs and he was unable to walk
without the help of an attendant or a stick.
Bulky first molars and a deep fissure at the
mid-palate were also noted. Wormian bones of the
skull with non-fusion of cranial sutures were
seen. The deep fissure would have been caused by
non-fusion of the mid-palatal suture.
Some cases of fractured jaw bones during
tooth extraction have been reported in the
literature. To the best of our knowledge, no
case of spontaneous fracture has been reported
in the English literature during yawning and our
patient is probably the first reported case of
spontaneous fracture in a patient with OI. The
patient had poor oral hygiene which would have
caused vertical bone loss and produced further
weakness of the bone. No treatment is available
for OI as it is a genetic disease. However,
bisphosphonates including pamidronate,
zoledronate, alendronate and risedronate have
been used by clinicians. Bisphosphonates
interfere with osteoclastic activity by
preventing, inhibiting and early apoptosis of
osteoclasts. They increase the bone density so
the frequency of fractures is decreased and
ultimately the quality of life is improved. High
doses of bisphosphonates may cause
osteoradionecrosis.
The limiting factor in OI is the fragility
of the bones which are frequently fractured.
Although fractures of facial bones are rarely
seen, they need special attention. Fracture of
dentate fragments and non-displaced fractures
can be treated by closed reduction but displaced
fractures and fractures beyond the angle of the
mandible pose difficulty in treatment and need
open reduction and fixation. Surgery in these
patients must be undertaken with particular care
as they are compromised, having a short neck,
kyphosis, scoliosis, pectus carinatum (pigeon
chest) or pectus excavatum, cardiac
abnormalities, bleeding due to platelet
dysfunction and hyperthermia.
