Original Article
Congenital Trismus Secondary to Masseteric
Fibrous Bands: A 7-Year Follow-Up Report
as an Approach to Management
Adrian M. Skinner, MBChB Martin J. W. Rees, FRACS
Auckland, New Zealand
A 7-year prospective follow-up report, which was
previously presented in this journal as an initial
pediatric case report, is presented as an approach to
management of congenital trismus secondary to
masseteric fibrous bands. Adams and Rees discussed management, including endoscopic exploration at 18 months of age with early recurrence of
trismus. Under the care of the same plastic surgeon
and his team, the progress of this patient over 7
years has given us an insight into management. The
cause of trismus is not fully elucidated, but the
condition can result in compromised caloric intake,
speech development, facial appearance, dental care,
and oral hygiene. The decreased oral opening may
be secondary to shortening of the muscles of mastication, which may cause tension moulding and
distortion of the coronoid process; yet, there is no
consensus on the optimal management of temporomandibular joint trismus and all its causes. The
patient presented in this report, now aged 7 years,
has proceeded through to open surgery on two occasions yet, regrettably, has persistently tight masseter muscles and only 8 mm of jaw opening.
Key Words: Congenital trismus, pseudocamptodactyly syndrome, masseteric fibrous bands
T
rismus, derived from the Greek trimos
meaning “grating” or “grinding,” is an inability to open the mouth.1 It involves tonic
contraction of jaw-closing muscles and is a
symptom either of general disease affecting nerves or
joints or of local disease leading to reduced mouth
From the Plastic and Reconstructive Surgery Department, Middlemore Hospital, Counties Manukau District Health Board,
Otahuhu, Auckland, New Zealand.
Address correspondence to Mr Rees, Plastic and Reconstructive
Surgery Department, Middlemore Hospital, Counties Manukau
District Health Board, Otahuhu, Auckland, New Zealand; e-mail:
MRees@middlemore.co.nz.
opening.2 The normal range of maximal mouth
opening in adults, measured as the interincisal distance, varies within a range of 40 to 60 mm,1 although a lower limit of 23 mm and an upper limit of
68 mm are reported.3 Variations reflect age and sex.4
In general, males display greater mouth opening.5
The etiology of trismus includes infection,
trauma, dental treatment, temporomandibular joint
(TMJ) disorders, and congenital problems.1 The differential diagnosis of congenital trismus includes interalveolar synechiae most commonly,6 TMJ bony ankylosis,2 distal arthrogryposes,7,8 Hecht syndrome,9,10
and abnormalities of the muscles of mastication.11
Clinical Management
The patient we discuss presented with profound congenital trismus with associated impaired feeding and
sucking. 11 In addition, she had evidence of a
“floppy” neck, a tendency to arch her back on crying,
minor outpouching of the upper esophagus, increased tone in the anterior left leg compartment
muscles, shortened leg muscles, and ocular motor
dyspraxia. The pterygomandibular raphe was noted
to be tight on both sides, with associated masseteric
spasticity. Computed tomography showed no evidence of bony fusion, and magnetic resonance imaging was reported as normal. When she presented for
endoscopic-assisted exploration at 18 months of age,
the interincisal distance was measured at 4 mm actively and 12 mm passively. Under general anesthesia, mouth opening was measured at 20 mm. During
this procedure, tight fibrous bands on the anterior
surface of the masseter muscles were identified and
released, resulting in 30 mm of opening. Histological
findings confirmed the presence of fibrous tissue
along with muscle atrophy. Unfortunately, trismus
recurred 3 months after surgery, with early relapse
noted at 6 weeks.
At 29 months after this early procedure, or at 3
years of age, jaw opening was measured at 8 mm.
This was preventing dental impressions for creating
spring-loaded plates for jaw physiotherapy. Food
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THE JOURNAL OF CRANIOFACIAL SURGERY / VOLUME 15, NUMBER 5 September 2004
chewing was also a problem. In addition, although
the patient was developing language and speech
ability, she was noted to be not fully intelligible.
Neurodevelopmentally, she was reported as making
good progress at about 6 months behind her peers.
At 43 months after her initial endoscopic procedure, shortly after turning 5 years of age, the patient’s jaw opening was measured at 5 to 6 mm. Five
months later, she proceeded to surgery under general anesthesia in an attempt to free up this limited
opening. An incision was made in the upper buccal
sulcus on both sides of the mouth taken laterally just
outside the pterygomandibular raphe. Access was
then gained to the lateral border of the coronoid process; from there, the deep surface of the masseter
muscle on each side was dissected, including the
outer surface. There were some small fibrous bands
in each muscle that were divided, but this made no
difference to jaw opening. The stiffness of the jaw
was quite profound, and it appeared to be ankylosed
because of fibrosis around the TMJs, which were free
at the previous procedure. Unexpectedly, apart from
some minor masseteric bands, these bands had not
reformed. Ten units Clostridium botulinum type A
toxin (Botox) and 0.4 ml saline were injected in four
positions into each masseter muscle through the intraoral incision. Incisions were closed with interrupted 5/0 absorbable sutures.
Fig 1 Muscles involved in congenital trismus. M (masseter): T (temporalis): MPt (Medial Pterygoid). The endoscope was introduced in two places (a) deep to the upper
pole of the ear, thence deep to the deep temporal fascia,
and (b) through the buccal mucosa lateral to the pterygomandibular raphe anterior to the coronoid process of the
mandible. Fibrous bands were seen in the anterior border
of the masseter, medial pterygoid and the temporalis. The
latter looked normal but there were bands to the underside
of the maxillary buttress and zygomatic arch which were
divided ‘blind’ after dividing the masseteric and pterygoid
bands under direct vision. Release of all three bands on
each side permitted the jaw to be fully opened.
710
After a further 5 months, the patient proceeded
to further surgery, again under general anesthesia, to
open release of fibrosis scarring subsequent to previous findings. An incision was made in front of the
coronoid process and vertical ramus of the mandible,
taking it down to the lateral aspect of the angle of the
mandible. The masseter muscles were freed up from
the lateral surface of the mandible right down to
their insertion on the angle of the mandible on both
sides, allowing an additional 10 mm of jaw opening.
A further dissection of fibrous scarring around the
pterygomandibular raphe gave a little extra movement. The coronoid processes were then traced up
into the infratemporal fossa, and further fibrosis in
this area was released. Then, by exerting pressure on
the mandible, it suddenly came free as some of the
residual fibrosis tissue gave way, resulting in a 40mm opening. Botox was then used to paralyze the
masseter, medial pterygoid, and temporalis muscles,
with 10 U being injected into both masseters and
both medial pterygoids and 5 U into each temporalis
muscle in its anterior part, leaving the posterior part
for some weak closure. Finally, dental impressions
were taken to make dental models and splints to
protect the patient’s teeth when using a Therabyte to
help maintain jaw opening.
The patient’s family moved, and she was seen
by a pediatrician at 61⁄2 years of age. At this stage,
baseline jaw opening was noted to have decreased to
15 mm, with an increase to 18 mm achieved via Therabyte. Although still allowing for an electric toothbrush, it was noted that the patient was choking on
food of a “more lumpy consistency.” Language was
reported to be good and even above average for the
patient’s age in spite of some intermittent staccato
delivery of speech. At this stage, daily Therabyte was
still being applied to maintain or improve jaw opening. Nevertheless, it should be noted that although
jaw opening was being sustained after surgery with
the use of the Therabyte initially, this first Therabyte
broke, with a resulting delay of at least 3 weeks before replacement. During this stage, the amount of
jaw movement was reported by the patient’s parents
to decrease significantly, and they were subsequently unable to recover this movement.
At 7 years of age, the patient was referred back
to her original plastic surgical consultant for followup. Jaw opening was now reported to be disappointing at only 8 mm. Her parents were no longer able to
use a normal-sized toothbrush for teeth cleaning and
were using a “cut-down” modified toothbrush. In
addition, the patient was now unable to chew her
food adequately. This may also have been caused by
a muscular coordination problem with her tongue
CONGENITAL TRISMUS / Skinner and Rees
and cheeks, probably attributable to her syndrome.
On examination, the masseter muscles were noted to
be tight again, despite use of Botox at the previous
surgery. The patient was again noted to be slightly
delayed for her age developmentally.
At this stage, further Botox treatment is under
consideration. In addition, the patient is undergoing
tongue exercises with a speech therapist to improve
chewing. She will continue to be followed up.
DISCUSSION
his is an interesting case of trismus in a patient
with presumed sporadic trismus-pseudocamptodactyly syndrome. Lefaivre and Aitchison12 note that
only two cases of pediatric patients with this syndrome who have proceeded to surgery are reported
in the literature.
Trismus-pseudocamptodactyly, or Hecht,
Hecht-Beals, or Hecht-Beals-Wilson syndrome, a rare
autosomal dominant condition with variable penetrance, is a disorder of muscle development and
function involving short muscle and tendon units
that limit range of motion.12 The most consistent feature of this syndrome is trismus, but upper and
lower extremities are affected also.13 Not all deformities are present in each affected person, with limited mouth opening and pseudocamptodactyly occurring most frequently.14
Trismus presents the most serious threat to these
individuals, with resulting compromise to caloric intake, speech development, facial appearance, and
dental care and oral hygiene.1,13 In addition, intubation can be difficult and hazardous.15,16 Affected individuals have been reported to take twice the usual
time to consume a meal.9 Some infants are unable to
accept a conventional rubber nipple between their
gums,17 and tonsillectomy is difficult.17 Furthermore,
general anesthesia does not relieve the trismus.17,18 It
is noted, however, that in old age, affected individuals have a larger mouth opening, thereby allowing
dentures to be worn, perhaps because of resorption
and remodeling of the mandible.17
The cause of trismus is not fully elucidated. No
radiographic evidence of abnormality of the TMJs
has been found.9,17,19,20 De Jong21 suggested the presence of an abnormal maxillomandibular ligament.
Ter Haar and Van Hoof20,22 described enlargement
of the coronoid process confirmed radiologically.
This same abnormality was noted by Mabry et al,17
but unlike Ter Haar and Van Hoof,20,22 they found
no correlation between extent of coronoid enlargement and degree of limited movement. They suggested that decreased opening may be secondary to
T
shortening of the muscles of mastication, particularly
of the temporalis, which could cause tension moulding and distortion of the coronoid process. They note
that in pronounced cases of trismus, the coronoid
process is enlarged by extensive pull of the temporalis muscle tendon unit, which decreases mandibular excursion.20 In turn, the enlarged coronoid process impinges on the body of the zygomatic bone and
inner margin of the arch, explaining limited mandibular excursion.23
The most frequently reported upper extremity
abnormality involves pseudocamptodactyly, which
presents as a bending of the fingers on dorsiflexion at
the wrist because of shortening of the flexor tendonmuscle unit.14 Unlike camptodactyly, this deformity
is neither fixed nor progressive.13 Children may
crawl on clenched fists with their weight resting on
the knuckles.17
About 5% of affected individuals have foot and
leg problems.17 Lower extremity anomalies may include short hamstring muscles, short gastrocnemius
and hamstring muscles with associated pelvic tilt,
talipes equinovarus, “clubfeet,” “hammer toes,”
metatarsus varus, and calcaneovalgus deformity.13,17
Other deformities have also been noted. Stature
is reduced in some individuals, although they are
normally proportioned.4 Others have reported prognathism,10 blepharochalasis,21,24 a quilted appearance of the cheeks,21 ptosis,17 and micrognathia.14
Our patient, although displaying no clear evidence of the typical autosomal dominant inheritance
pattern or of pseudocamptodactyly, does have evidence of trismus with normal radiological findings
with shortened leg muscles. There is some similarity
to this case with the presentation of a 53-year-old
female patient with this syndrome described by Mercuri,24 as noted previously by Adams and Rees.11
Several features of the syndrome, including trismus
and pseudocamptodactyly, were noted at the time of
this woman’s dental surgery, and she proceeded to
open surgery, during which fibrous bands found bilaterally anterior to the masseter muscles were cut
and reported as consistent with tendon. Her family
history is unavailable, however. Adams and Rees11
also note some lesser similarities to a patient presenting with arthrogryposis congenita multiplex type II
subtype E (a syndrome of sporadic inheritance characterized by a distinctive hand abnormality, trismus,
other contractures, short stature, micrognathia,
webbed duck scoliosis, and mental retardation).8
There is no consensus on the optimal management of TMJ ankylosis in this patient population.
Lefaivre and Aitchison12 recently presented the case
of a 28-month-old boy with trismus-pseudocampto711
THE JOURNAL OF CRANIOFACIAL SURGERY / VOLUME 15, NUMBER 5 September 2004
dactyly syndrome and a limited mouth opening of 6
mm whose initial treatment involved an open surgical approach after no improvement with jaw physiotherapy. This patient underwent extensive subperiosteal dissection of the mandible, bilateral
coronoidectomy (because of bilateral impingement
on the zygomatic arch), and TMJ exploration. An initial intraoperative opening of 18 mm was achieved,
although mouth opening decreased to 12 mm in the
weeks immediately after surgery. This was corrected
with physical therapy, and 1 year after surgery, the
authors report a successful outcome with active
mouth opening at 25 mm. They also note that the
patient’s father, who was diagnosed with the same
syndrome, displayed a similar range of motion without surgery.
Follow-up of our patient and of the patient presented by Lefaivre and Aitchison12 will be interesting. In addition to the relapse after the endoscopic
procedure in our patient, other authors have described progressive relapse after correction.14,15 It is
interesting to note that Lefaivre and Aitchison12 have
attributed the absence of relapse in their patient to
continuous jaw physiotherapy independent of surgical technique. They note that long-term therapy may
be the most important variable affecting long-term
outcome and advise waiting until cooperation is optimal to avoid otherwise necessary intervention.
Hirano et al6 also note the importance of postoperative manipulation after initial surgery in achieving
normal mouth opening, especially because the TMJ
may have been restricted in its movement during the
fetal period.25–27 Markus4 operated on a 23-year-old
man with a mouth opening of 11 mm, which increased to 30 mm after bilateral coronoidectomy and
was measured at 27 mm at 2 years of follow-up. He
also attributed sustaining mouth opening to compliance with postoperative therapy. This is interesting,
because the patient we present here was initially unable to comply at a young age with physiotherapy
and splinting initiated after the endoscopic procedure. In addition, her jaw opening decreased after
subsequent open surgery while waiting 3 weeks for a
replacement Therabyte.
CONCLUSION
t is interesting to note the different approaches to
management of trismus in the pediatric population. We present a patient who initially underwent
an endoscopic procedure at 18 months of age but,
subsequently, has required two open surgical procedures. Lefaivre and Aitchison12 present the case of a
patient, also in the pediatric population, who under-
I
712
went initial open surgical procedure at 28 months of
age. There are advantages associated with both procedures. From reviewing these two cases, it is clear
that although the early endoscopic approach may allow minimally invasive access,28 decreased scarring,
less postoperative pain, shortened hospital stay, and
earlier rehabilitation,11 the early open approach may
allow for avoidance of the early relapse described in
our patient and also for stability of correction.12 Subsequent open surgery at 5 years of age in the patient
presented has also, unfortunately, resulted in relapse. The management of future additional cases
and follow-up of the two pediatric cases reported to
date will hopefully provide some answers to the
complex and interesting issue of care for patients
with trismus. In any case, compliance with therapy
and optimal age for surgery seem to be important
considerations.
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