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Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report
Sung-Tak Lee, In-Kyo Chung
Department of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, Yangsan, Korea
Abstract (J Korean Assoc Oral Maxillofac Surg 2012;38:249-54)
Bilateral coronoid process hyperplasia is a rare condition characterized by an enlarged mandibular coronoid process. The painless progressive reduction of a mouth opening is caused by coronoid process impingement on the posterior aspect of the zygomatic bone. Hyperplasia of the bilateral coronoid process leads to the restriction of a mandibular opening consequent to the impingement of the enlarged coronoid process on the temporal surface of the zygomatic bone or with the medial surface of the zygomatic arch. The process has been diagnosed as developmental hyperplasia. Otherwise, the development of the coronoid process may be associated with growth hormone. This paper describes a case of trismus caused by coronoid hyperplasia in an idiopathic short-stature patient who received growth hormone therapy by somatropin injections.
Key words: Coronoid process hyperplasia, Trismus[paper submitted 2011. 9. 28 / revised 2011. 11. 2 / accepted 2011. 11. 18]
upliftontheupperpartofthezygomaticarchandmandibular
displacementtowardtheaffectedsideduringmouthopening.
Unilateralandbilateralcoronoidprocesshyperplasiamay
occurinallagegroups(average25)butrarelyinpeopleaged
10orunder.Moreover,mostpatientsweremale,butfemale
patientswererare.
As a treatmentmethod, coronoidectomycanachieve
meaningfulenhancementofmouthopening,but thereisa
needtocheckforfibrosiscausedbysurgeryorregrowthof
coronoidprocessforalongtime2.
This case reportdealswith apatientdiagnosedwith
idiopathicshortstature (ISS) in2008by theDepartment
ofPediatricsandadministeredgrowthhormone therapy
andwhose trismus-causedbybilateralcoronoidprocess
hyperplasia-wastreatedwithcoronoidectomy.
II. Case Report
OnApril4,2006,a12-year-oldmalepatientvisitedthe
DepartmentofPediatricDentistryandOrthodontics,Pusan
NationalUniversityHospitalKoreadue to thedelayed
eruptionofpermanentteethandfacialasymmetry.Thepatient
weighed34kg,andhewas135cmtall;hewasrelatively
smallcomparedwithotherchildreninhisage,andmanyof
histeethhadbirthdefects.Thepatienthadreceivedtreatment
I. Introduction
BilateralCoronoidProcessHyperplasiaisararecondition
characterizedbyanenlargedmandibularcoronoidprocess.
Continuouslyproliferatingcoronoidprocesscausestrismus
duetoimpingementonthetemporalsurfaceofthezygomatic
boneorthemedialsurfaceofthezygomaticarch.According
toIsbergetal.1,coronoidprocesshyperplasiais thecause
ofapproximately5%oftrismuspatients.Manyhypotheses
suggeststimulatingendocrine,increasedactivityoftemporal
muscle, injury,andheredityasthepossiblefactorscontri-
butingtocoronoidprocesshyperplasia,butthecausehasyet
tobeidentifiedclearly2.
Themostcommonclinical featureofcoronoidprocess
hyperplasiaispainlessandprogressivetrismus.Unilateral
coronoidprocesshyperplasiaiscommonlycombinedwith
facialasymmetryandsometimescombinedwithmobile
In-Kyo ChungDepartment of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, 20, Geumo-ro, Mulgeum-eup, Yangsan 626-787, KoreaTEL: +82-55-360-5100 FAX: +82-55-360-5104E-mail: [email protected]
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
CC
CASE REPORThttp://dx.doi.org/10.5125/jkaoms.2012.38.4.249
pISSN 2234-7550·eISSN 2234-5930
J Korean Assoc Oral Maxillofac Surg 2012;38:249-54
250
2008.(Fig.1)Moreover,hehadahard-end-feelonbothsides
whenopeninghismouthtotheleftandright.Thepanoramic
radiographic inspectionanddentalcone-beamcomputed
tomography(CT)(Pax-Zenith3D;Vatech,Hwaseong,Korea)
imagesshowedhyperplasiaonbothsidesofthemandibular
coronoidprocess.(Fig.2)Inparticular,thethreedimensional
(3D)imagesobtainedbyreorganizingthedentalcone-beam
CTimageswith3Danalysisprogram(Simplant;Materialise,
Leuven,Belgium)revealed that the leftcoronoidprocess
wasclosetothemedialsurfaceoftheleftzygomaticbone,
and that the inner sideof the left zygomaticbonewas
transformed.(Fig.3)Thepatient’sheightincreasedfrom143
cminJanuary2008whenthegrowthhormonetherapywas
startedto153cmwhenthepatientvisitedusinAugust2008
duetotrismus.Andincomparingpanoramicradiographs,
thepanoramicimagestakeninAugust2008showedamore
noticeablehyperplasiaintheleftcoronoidprocess.(Fig.4)
Thepatientkept receivinggrowthhormone therapyuntil
October2009,andhisheight increased from153cm to
167cminJuly2011.Themaximummouthopeninglevel
decreasedfrom15mminAugust2008to10mminJuly
2011.(Table1)
Therefore,basedonthepatient’smedicalhistory,clinical
examinations,andradiographicinspection,wedetermined
at theDepartmentofPediatricDentistryandOrthodontics
without trismus; inAugust2008whenhewas14,hewas
referredtoDepartmentofOralandMaxillofacialSurgeryby
theDepartmentofOrthodonticsduetofacialasymmetryand
trismus.Clinicalexaminationsrevealedfacialasymmetry,
mouthopening levelof15mm,anddisplacement to the
leftofthemandibleduringmouthopening;thepanoramic
photographsshowedleftcoronoidprocesshyperplasia.The
patientdidnothaveanyparticular injuryor infectionor
familyhistoryofsimilarsymptoms,buthewasdiagnosed
withISSinJanuary2008bytheDepartmentofPediatrics
inourhospitalandadministeredgrowthhormonetherapy
usingEutropin (RecombinantHumanGrowthHormone
[somatropin],LGEutropinInj.;LGLifeSciences,Seoul,
Korea) injection.OurDepartmentplanned toencourage
activemouthopeningmovement,observehisstatusduring
thegrowthperiod,andperformsurgery,butthepatientdid
notvisitagain.Later,thepatientvisitedagaininJuly2011
whenhewas17duetorestrictionofmouthopening.Clinical
examinationsrevealedfacialasymmetry,displacementtothe
leftofthemandibleduringmouthopening,andmaximum
mouthopening levelof10mm,decreasingcompared to
Fig. 1. Preoperative clinical photograph. A. Lateral photo view. B. Frontal photoview. C. Preoperaive maximum mouth opening mesurement was 10 mm.Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
A
B C
Fig. 2. Preoperative radiologic view show both hyperplasic coronoid preocess. A. Panoramic view. B. Dental conbeam com-puted tomography (CT) view (mandible right). C. Dental conbeam CT view (mandible left).Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report
251
thatthegrowthhormonetherapycausedhyperplasiainthe
bilateralmandibularcoronoidprocessanddiagnosed the
transformationoftheleftcoronoidprocessandimpingement
on the innersideof thezygomaticboneas thecauseof
trismus.Assuch,weplannedtoperformcoronoidectomyon
bothsidesofthemandibleundergeneralanesthesiainAugust
2011.
General anesthesiawasperformedwithnasotracheal
intubationusingfiberopticscopebecause itwashard to
executenasotrachealintubationusingheadscopeduetothe
insufficientmouthopeninglevel.Consideringthediagnostic
process,leftcoronoidectomywascarriedoutfirstduetothe
hard-end-feelingand transformationofcoronoidprocess.
At first, leftcoronoidectomywasperformed through the
mouth;however,dueto insufficientmouthopeninglevel,
thesubmandibularapproachwastaken.After thesurgery,
themaximummouthopening level increasedby37mm.
Afterward, rightcoronoidectomywasdone through the
intraoralapproach.Afterthesurgery,themaximummouth
Fig. 3. Three dimensional simplant image. A. The image show morphological abnomality of left zygomatic bone. B. Left coronoid process extend above the zygomatic bone and impinge on the posterior surface of the zygomatic bone. C. Right coronoid pro-cess have just hyperplastic morphology.Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
Fig. 4. Serial panoramic view. A. April 2006. B. August 2007. C. August 2008 after growth hormone therapy (January 2008). D. July 2011.Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
A B C D
Table 1. Trismus according to growth hormone therapy
Date(yy/mm/dd)Growth
hormonetherapyHeight(cm) Mouthopening
2006/42008/1/12008/1/212008/2/182008/4/142008/7/22008/7/302008/8/262008/10/212009/7/312009/10/52011/8/8
××
Eutropin21vialEutropin42vialEutropin75vialEutropin80vialEutropin21vialEutropin42vialEutropin42vialEutropin45vialEutropin45vial
×
135143143144148151152154156160161167
W.N.LW.N.LW.N.LW.N.LW.N.LW.N.LW.N.L15mm
---
10mm
(W.N.L:withinnormallength)Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
J Korean Assoc Oral Maxillofac Surg 2012;38:249-54
252
opening level increasedby53mm.(Fig.5)Extracted left
coronoidprocesshadhyperplasiahorizontally;cartilage
proliferating2mmthickwasnotedat theend.Extracted
rightcoronoidprocesswasnottransformed,butithadoverall
hyperplasia.(Fig.6)
Onemonthafterthesurgerywhenthepatientvisitedagain,
themaximumvoluntarymouthopeninglevelwas40mm
withoutedema,pain,andneuraldamage.(Fig.7)
III. Discussion
Generally,trismusmeansallproblemsinmouthopening.
Thenormalmouthopening level is40-60mm,basedon
Fig. 5. A. Perioperative mouth opening was 10 mm. B. Mouth opening after left coronoidectomy was 40 mm. C. Mouth opening after both coronoidectomy was 53 mm.Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
Fig. 6. A. Resected Lt. coronoid pro-cess. B. Lt. coronoid cartiladge from coro noid process tip. C. Comparison re sected Lt. coronoid process with re-sected Rt. coronoid process. (Lt.: left, Rt.: right)Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
Fig. 7. A. One month mouth opening after surgery. B. Post ope-rative panoramic view. Sung-Tak Lee et al: Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report. J Korean Assoc Oral Maxillofac Surg 2012
Severe trismus due to bilateral coronoid process hyperplasia in growth hormone therapy patient: a case report
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growthhormone stimulatesoverall bones andmuscles
particularlythegrowthofcartilagethroughtheinsulin-like
growthfactorI(IGF-I).Pirinenetal.14alsostatedthat the
growthofbasiscraniumandmandibularcartilageisaffected
bybothexcessandinsufficiencyof thegrowthhormone.
Considering these researchstudies, insufficientvertical
growthinthemandibularcondyleandposteriorskullbase
inchargeofcartilagegrowthcausessmallmandibleand
shortposteriorfacialheight,eruptionofdentitionincrease,
lowerfacialheight,andmandiblerotatedclockwise;hence
theuniquecraniofacialshapeofshort-staturepatients.The
patientinthiscasealsohadthefacialshapeofshort-stature
patients.
Agrowthhormoneagent(Somatropin)meansasynthetic
humangrowthhormone.Since1958whenRaben15injected
ahumangrowthhormoneextractedfromthepituitarygland
ofacadaverintoapatientwithgrowthhormonedeficiency
for thefirst timeandreporteditseffects, ithasbeenused
for40years.Thegrowthhormonestimulates thegrowth
ofbonesandmusclesaswellasthecompositionofIGF-I
in liver.Therefore, the injectionofgrowthhormonecan
resolvetheproblemofinsufficienthormoneaswellaslow
sensitivitytogrowthhormone,therebyincreasingthefinal
heightbystimulatinggrowthduringchildhoodandtriggering
thegrowthofspheno-occipitalsynchondrosisinbasiscranii
andmandibularcondyle.Actually,Chungetal.16reported
that2yearsofgrowthhormonetherapyforchildrenwith
shortstatureledtotheincreaseofposteriorfacialheightand
growthofthemandible.
Thoughthereisnoothercasereportontherelationship
between thegrowthof themandibularcoronoidprocess
andgrowthhormoneaswellasconsequentcomplications
suchastrismus,thiscasereportconcludedthatthecoronoid
processoriginatingwithcartilagemayhavehyperplasiaof
themandibularcoronoidprocessduetothegrowthhormone
agentandcontractionof temporalmuscle.Nonetheless,
moreresearchontheevidentreasonisneededtoidentifythe
mechanismofcoronoidprocesshyperplasia.
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