Surgical Science, 2010, 1, 27-29
doi:10.4236/ss.2010.11006 Published Online July 2010 (http://www.SciRP.org/journal/ss)
Endoscopic Adenoidectomy Secondary to Drug-induced
Trismus
Mark Greenberg M. D.1, Daniela Carvalho M. D.2
1Department of Anesthesiology and Pediatrics University of California, San Diego, USA
2Department of Otolaryngology, Head and Neck Surgery University of California, San Diego, USA
Received June 15, 2010; accepted July 13, 2010
Abstract
We present the case of a 4 year old girl whose adenoidectomy had to be performed via an endoscopic-trans-
oral approach due to the unexpected inability to fully open the mouth during the procedure. The patient had
previously been taking Risperidone for behavioral symptoms associated with her autism. The jaw tone re-
turned to normal following the procedure and there were no complications. An interaction between the
Risperidone and the anesthetics were the likely cause of the trismus.
Keywords: Adenoidectomy, Endoscopic, Trismus, Risperidone, Masseter Spasm
1. Introduction
Adenoidectomy is one of the most common same-day
surgeries performed by otolaryngologists. One of its in-
dications is to reduce the size of hypertrophic adenoids
which can cause airway obstruction [1]. Normally, the
procedure is performed transorally using a laryngeal
mirror to indirectly visualize the anatomy of the naso-
pharynx. Some physicians perform the adenoidectomy
transnasally. We prese nt the case of a 4 year old girl
whose adenoidectomy had to be performed via an endo-
scopic-transoral approach due to the unexpected inability
to fully open the mouth during the procedure.
2. Case Report
A four year old, 17 kilogram female, with a history of
obstructive sleep apnea and chronic otitis media was
scheduled to undergo an a denoidectomy and bilateral
myringotomy with tube placement. She had a significant
history of environmental allergies. She also had a history
of autism, and was on Risperidone. Pre-operative ex-
amination revealed bilateral serous middle ear effusion
and was otherwise normal.
After inhalational induction of anesthesia with Se-
voflurane and nitrous oxide, the myringotomy and tube
placement was accomplished without incident. After
increasing the anesthetic depth with 40 mg of Propofol
and 25 micrograms of Fentanyl, the patient underwent
direct laryngoscopy and tr acheal intubation. Placement
of the endotracheal tube was extremely difficult secon-
dary to the inability to fully open the mouth. A grade 3
view was obtained and tracheal position of the tube was
confirmed by auscultation of the lungs and denoting
carbon dioxide on the capnograph. After positioning the
patient in the Rose position, a shoulder roll was placed.
A Crowe-Davis mouth gag was placed with some diffi-
culty. Only a small opening of the mouth was able to be
obtained with the mouth gag. Assessment of the tem-
poromandibular joint (TMJ) revealed no dislocation, but
movement of the mandible was unsuccessful. Due to
severely limited mouth opening, the mouth gag could not
be extended to allow visualization of the adenoids with
the laryngeal mirror. Anesth esia was deepened by in-
creasing the Sevoflurane, and 20 mg of succinylcholine
was administered to remove any possibility of increased
muscle tone as the cause of the trismus. Several further
attempts at visualizing the adenoids transorally were un-
successful, so a nasal endoscopy was performed. A 2.7
mm 0 degree nasal endoscope was inserted through the
left nostril to visualize the nasopharynx. This revealed
moderately enlarged adenoids. The nasal cavity was felt
to be small to be able to accommodate the instruments
for a transnasal adenoidectomy. At this point we opted to
proceed with the adenoidectomy through the mouth with
suction cautery while the adenoids were visualized tran-
sorally with a 70 degree 4 mm nasal endoscope. The
adenoids were removed with suction cautery without
incident. The estimated blood loss was less than 1 cc.
The patient was taken to the recovery room and the tra-
chea was extubated. After recovery from anesthesia the

28 M. D. M. GREENBERG ET AL.
patient was found to have normal movement of the TMJ.
The patient recovered well with complete resolution of
her sleep apnea. On follow-up, at 1 and 6 months after
the procedure, the patient continued to have no issues
with trismus or TMJ pain.
3. Discussion
Adenoidectomy is a routine procedure for otolaryngolo-
gists. It is most commonly performed transorally with the
help of a mouth gag [1]. Several instruments can be used
to remove the adenoids, including a curette, adenotome,
suction cautery, Coblator® and a microdebrider. Another
method is to remove the adenoids transnasally with the
use of nasal endoscopes for visualization and removal of
the adenoids with powered instruments [2,3]. There has
also been reported the use of the transnasal visualization
with transoral removal of the adenoid tissue [4]. All tech-
niques have different advantages and complications.
Most surgeons in the UK do not use direct visualization
of the adenoids during the surgery. They use direct pal-
pation instead [5]. Visualization of the adenoids provides
the ability to remove them with more control of the
bleeding and surrounding structures. For this reas on, in
our institution, adenoidectomy is routinely performed
using indirect visualization through a mirror. Some au-
thors report the use of endoscopes through the nose to
visualize the adenoids, while these are removed through
the mouth. As our patient had significant trismus, we
were not able to perform the surgery in the conventional
fashion for our institution. As mentioned above, we util-
ize indirect visualization of the adenoids through a mir-
ror in the oral cavity and the removal is performed
through the same route with a curette, suction cautery or
microdebrider. In this specific patient, after evaluating
the adenoids through the nasal cavity it was felt that her
nasal cavity would be small for a larger endoscope, suc-
tion cautery or a large m icrodebrider. We opted to visu-
alize the adenoids through the mouth with a 70-degree
endoscope and use the suction-cautery to promote the
most efficient hemostasis and prevent bleeding. Despite
the poor mouth opening, this was performed without
difficulties.
Our patient had an unexpected episode of trismus that
did not improve with the time, increasing the anesthetic
depth or the use of muscle relaxants. Trismus in awake
children is usually secondary to trauma to the mandible
or problems in the condyle. Our p atient’s trismus oc-
curred after induction and subsided once she recovered
from anesthesia. At the time of surgery she was taking
Risperidone. Risperidone is an atypical antipsychotic that
is used in children with autism to decrease agitation [6-8].
One of the side effects of this medication is m uscle
spasm. There is a report of an autistic patient who was
taking both Methyphenidate and Risperidone in whom
unilateral dystonia of the masseter muscle was reported
[9]. Risperidone has also been associated with the neu-
roleptic malignant syndrome, which can result in rigidity
[10]. Although this patient exhibited masseter rigidity,
she had none of the other symptoms associated with this
condition. One hypothesis is that the trismus was caused
by synergism of the Risperidone with the volatile anes-
thetic, Sevoflurane. We do not believe that the trismus
was the result of inadequate anesthetic depth. The patient
had no response to surgical stimulation and her vital
signs suggested she was in a deep plane of anesthesia.
Succinylcholine itself can cause trismus, but was not the
cause in this case, as the trismus occurred before the suc-
cinylcholine was given [11,12]. Nerve stimulation
showed complete ablation of neuromuscular function.
The fact that the trismus did not subside with the use of
muscle relaxants, but completely resolved after she woke
up from the anesthetic, suggests a mechanism unrelated
to the succinylcholine. There are no reports in the litera-
ture about volatile anesthetics, Risperidone and trismus,
but it is likely the muscle spam in the masseter muscle
was the result of the combination of Risperido ne and
Sevoflurane. One can hypot hesize that the patients’ au-
tism had an effect on the brain making the patient more
susceptible to trismus. Behaviors such as with chronic
teeth grinding, are common in autistic patients [13]. It is
possible that either the Propofol or Fentanyl also con-
tributed to th e trismus, but this is unlikely given the
small doses used.
In summary, this is the first reported case of trismus in
association with Risperidone in an autistic patient result-
ing in the inability to perform adenoidectomy in the
standard transoral fashion. When mouth opening is an
issue, transoral adenoidectomy using a rigid endoscope
in an acce ptable alternative. In addition, anesthesiolo-
gists should be aware about this potential side effect of
Risperidone.
4. References
[1] M. B. Ugur, S. M. Dogan, A. Sogut, L. Uzun, F. Cinar, R.
Altin and M. Aydin, “Effect of Adenoidectomy and/or
Tonsillectomy on Cardiac Functions in Children with
Obstructive Sleep Apnea,” Journal of Oto-Rhino-Laryn-
gology and its Related Specialties, Vol. 70, No. 3, 2008,
pp. 202-208.
[2] F. Pagella, E. Matti, A. Colombo, G. Giourgos and E.
Mira, “How We do it: A Combined Method of Tradi-
tional Curette and Power-Assisted Endoscopic Adenoi-
dectomy,” Acta Otolaryngol, Vol. 129, No. 5, 2009 May,
pp. 556-559.
[3] K. A. Al-Mazrou, A. Al-Qahtani and A. I . Al-Fayez,
“Effectiveness of transnasal endoscopic powered adenoi-
dectomy in patients with choanal adenoids,” International
Journal of Pediatric Otorhinolaryngology, Vol. 73, No.
12, December 2009, pp. 1650-1652.
[4] Y. H. Jong and B. S. Gendeh, “Transoral Endoscopic

M. D. M. GREENBERG ET AL.
29
Adenoidectomy: Initial Experience,” The Medical Jour-
nal of Malaysia, Vol. 63, No. 1, March 2008, pp. 81-83.
[5] G. Dhanasekar, A. Liapi and N. Turner, “Adenoidectomy
Techniques: UK Survey,” The Journal of Laryngology &
Otology, Vol. 30, 2009, pp. 1-5.
[6] R. P. Malone and A. Waheed, “The Role of Antipsychot-
ics in the Management of Behavioural Symptoms in
Children and Adolescents with Autism,” Drugs, Vol. 69,
No. 5, 2009, 535-548.
[7] R. Canitano and V. Scandurra, “Risperidone in the
Treatment of Behavioral Disorders Associated with Au-
tism in Children and Adolescents,” Journal of Neuropsy-
chiatric Disease and Treatment, Vol. 4, No. 4, August
2008, 723-730.
[8] L. J. Scott and S. Dhillon, “Risperidone: A Review of its
Use in the Treatment of Irritability Associated with Au-
tistic Disorder in Children and Adolescents,” Paediatr
Drugs, Vol. 9, No. 5, 2007, pp. 343-354.
[9] M. A. Willemsen and K. G. van der Wal, “Medica-
tion-Induced Mandibular Luxation in a Seven-Year-Old
Patient,” Tijdschr Psychiatr, Vol. 50, No. 1, 2008, pp.
61-64.
[10] R. Sharma, B. Trappler, Y. K. Ng and C. P. Leeman,
“Risperidone-Induced Neuroleptic Malignant Syndrome,”
The Annals of Pharmacotherapy, July-August 1996, Vol.
30, No. 7-8, pp. 775-778.
[11] J. A. Ramirez, E. D. Cheetham, A. S. Laurence and P. M.
Hopkins, “Suxamethonium, Ma sseter Spasm and Later
Malignant Hyperthermia,” Anaesthesia, November 1998;
Vol. 53, No. 11, pp. 1111-1116.
[12] J. R. Kosko, B. W. Brandom and K. H. Chan, “Masseter
Spasm and Malignant Hyperthermia: A Retrospective
Review of a Hospital-Based Pediatric Otolaryngology
Practice,” International Journal of Pediatric Otorhi-
nolaryngology, January 1992, Vol. 23, No. 1, pp. 45-50.
[13] P. G. Monroy and M. A. “Da Fonseca the Use of
Botulinum Toxin-A in the Treatment of Severe Bruxism
in a Patient with Autism: A C ase Report,” Spec Care
Dentist, Vol. 26, No. 1, 2006, pp. 37-39.