Temporomandibular joint (TMJ) dislocation is a painful condition that occurs when
there is an undue forward movement of the condyle ahead of the articular eminence
with total separation of the articular surfaces and fixation in same position.
A 63-year-old female patient presented with diminished sensation over both lower limbs
and inability to walk for the last 2 months. Her magnetic resonance imaging (MRI)
study showed C6 to C7 vertebral body destruction with prolapsed D7 vertebral body.
She was posted for anterior cervical dissection and fusion at C6 to C7 level for which
auto graft bone was taken from iliac crest under general anesthesia. Her pre-anesthetic
check-up was unremarkable. Her mouth opening was more than three fingerbreadths, and
modified Mallampati score was 2. After attaching routine monitors, general anesthesia
was induced with fentanyl 100 µg, propofol 100 mg, and rocuronium 50 mg. Trachea was
intubated successfully with the help of video laryngoscope (KARL STORZ-ENDOSCOPE C-MAC
8401 ZX, Tuttlingen, Germany). After intubation, the jaw was in normal position. While
shifting the tube to fix on the left side using gloved fingers with video laryngoscope
in situ, we noticed that there was deviation of mouth toward the right side, and we
were not able to close her mouth. Left-sided TMJ dislocation was suspected, and manual
reduction of dislocation was tried before a consultation was sent to dental surgeon.
TMJ dislocation was corrected via intraoral route by dental surgeon after two attempts.
He put the thumb over the molar teeth of the patient and pushed the dislocated jaw
downward and backward. After jaw correction, surgery was resumed and was completed
with uneventful intraoperative course.
Factors commonly associated with TMJ dislocation are poor development of the articular
fossa, temporomandibular ligament or joint capsule laxity, excessive activity of the
lateral pterygoid and infrahyoid muscles, female gender, lesser inter-incisor distance,
previous TMJ pain, and increasing age.[1] TMJ loses some of the protection provided by tone of surrounding muscles due to
rotation and translation of the joint during direct laryngoscopy and jaw protrusion
during mask ventilation in anesthetized patient. This can lead to joint dysfunction
following uncomplicated direct laryngoscopy and endotracheal intubation in normal
individuals especially in old age and female patients. TMJ dislocation can be easily
missed in an anesthetized patient, and late reduction (over a period of months) of
the same can lead to joint fibrosis, adhesion, and difficult manual reduction necessitating
surgical reduction.[2] The American Society of Anesthesiologists recommends preoperative evaluation of
TMJ function especially with regard to limitations in the range of motion of the TMJ
and the ability to protrude the mandible voluntarily.[3] Further evaluation and treatment by dentist are needed in a patient with a history
or signs of TMJ disorder before any airway management.
Temporomandibular joint dislocations have been reported after laryngeal mask airway
insertion,[4] endotracheal intubation,[5] gastrointestinal endoscopy, transesophageal echography probe insertion, and after
tracheal extubation. In our case, dislocation occurred during shifting of tube from
the right to the left side of the mouth. The possible reason may be extra opening
of mouth, laxity of ligaments due to old age, and loss of protective reflex of muscles
surrounding TMJ due to administration of muscle relaxant.
If TMJ dislocation goes undetected, in postoperative period, the patient can have
pain in face and jaw, difficulty in closing mouth, problem in talking, drooling of
saliva, etc. We recommend gentle manipulation of airway and timely diagnosis of TMJ
dislocation in older female patients under general anesthesia. Anesthesiologist should
be trained in detecting and repositioning of TMJ dislocation. Our case is a reminder
of this painful complication following airway manipulation.
