Beighton, Peter

Fieggen, Karen

Holmes, Haly

Roberts, Tina

Stephen, Lawrence

South African Medical Journal (SAMJ)

August 2005, Vol. 95, No. 8  SAMJSCIENTIFIC LETTERTo the Editor: Achondroplasia is a relatively common geneticskeletal dysplasia that manifests with stunted stature anddisproportionate limb shortening.  Characteristic craniofacialfeatures include a prominent forehead, depressed nasal bridgeand maxillary hypoplasia.It is probable that there are between 500 and 1 000 personswith achondroplasia in South Africa, and it is inevitable thatthey will seek consultation and care in general and specialiseddental practices.  In this context, it is relevant that dental andorthodontic management is constrained by practical problemsassociated with upper airway obstruction and other primaryand secondary syndromic components.In order to provide a perspective on the situation in SouthAfrica, we assessed the special oro-dental needs of 10 affectedchildren.  Our findings are presented here. Patients and methodsTen children with a firm diagnosis of achondroplasia weredocumented at the Genetic Clinic of Red Cross Children’sHospital, Cape Town, in 2003.  After preliminary appraisal,they were seen in the Faculty of Dentistry, University of theWestern Cape, for detailed oro-dental assessment and theimplementation of ongoing specialised dental management.Investigations included Panorex views of the jaws and lateralskull radiographs for anthropometric analysis.  General observationsApart from small stature and short limbs, the affected childrenhad good general health, normal intelligence and buoyantpersonalities.  There were no internal ramifications, nobleeding tendency and no morbid obesity.  Several had legmalalignment but retained their agility.  The majority had largeheads, with possible arrested hydrocephalus, and in 2, shuntshad been implanted.The ambulant children had a mild lumbar lordosis but nonehad any significant spinal malalignment other than a thoraco-lumbar gibbus in one child.  None had any evidence of spinalcord compression, although several had chronic or intermittentbackache.Oro-facial observationsThe affected children all breathed by mouth because of upper-airway obstruction.  The teeth were normal in shape, textureand mechanical properties, and there was no impaction ormalalignment.  The mouth was wide, and the upper dentitionprominent.  Wide spacing of the teeth, which is oftenprominent in adulthood, was not seen in the children.Problems in oro-facial managementShort limbs, stunted stature and occasional spinalmalalignment made it difficult for the children to sitcomfortably in a conventional dental chair.  Chronic backachemay compound this problem.Upper airway obstruction due to depression of the nasalbridge, variable choanal atresia and enlarged adenoids resultedin mouth breathing.  A small nasal pharynx and larynx posedadditional problems for anaesthesia.The possible presence of cranio-cervical instabilitynecessitated special precautions in head control during dentalintervention.A large heavy head, sometimes with arrested hydrocephalusand an implanted shunt, made head control difficult.DiscussionAccording to Dunbar et al.1 the main orthodontic problem inachondroplasia is class III malocclusion consequent uponinherent shortening of the base of the skull; this abnormalconfiguration leads to retraction and decrease in vertical heightof the maxilla.Although the clinical features and natural history ofachondroplasia have been documented extensively, there is apaucity of information on the dental manifestations.  Forinstance, in a multicentre review of 193 affected persons, onlybrief mention was made of potential dental problems.2However, it was recorded that only 3% of the children in thisseries were regarded as having significant orthodontic needs.In the light of our experience in the orthodontic managementof 10 affected children, the main problems were related to thepractical aspects of dental care, rather than any specificabnormalities of the teeth and jaws.  These difficultiesconcerned mouth breathing because of the reduced calibre ofthe upper airways.  In this context, 8 of the 10 children had588Faculty of Dentistry, University of the Western CapeLawrence Stephen, BChD, MSc, PhDHaly Holmes, BChD, MScTina Roberts, BChD, MChDDivision of Human Genetics, Faculty of Health Sciences, University of Cape TownKaren Fieggen, MB ChB, FCPSAPeter Beighton, MB BS, MRCS, LPCP, DRCOG, DCH, MRCHP (Lond),MRCHP (Edin), MD, PhD, FRCP (Edin), FRCP (Lond), FRCPLH, MPhilCorresponding author: L Stephen (lstephen@uwc.ac.za)Orthodontic management of achondroplasia in South AfricaLawrence Stephen, Haly Holmes, Tina Roberts, Karen Fieggen, Peter Beighton588-589 pgs  7/27/05  3:49 PM  Page 588589August 2005, Vol. 95, No. 8  SAMJSCIENTIFIC LETTERexperienced repeated upper respiratory tract infections, withrecurrent otitis media and enlargement of the adenoids.The large heavy head, the small foramen magnum and thepossible abnormality of the cranio-cervical junction pose apotential threat of spinal cord compression.3,4 It is likely thatthis special risk applies to dental procedures, with or withoutgeneral anaesthesia, and careful control of the patient’s head iswarranted.  In South Africa, the presence of a thoraco-lumbargibbus in black children represents an additional potentialthreat to the spinal cord.5Cephalometric analysis of the craniofacial skeleton wasundertaken in 5 of the affected children in order to identify anyspecific features that might reflect ethnic diversity and impacton dental management in the South African situation.  Ourfindings were essentially in accordance with those previouslydocumented in a thesis by Pedersen,6 and by Cohen et al.7 in anextensive series of affected persons.  In particular, maxillaryhypoplasia and relative mandibular prognathism wereconsistent features.1. Dunbar JP, Goldin B, Subtelny JD. Correction of class I crowding in an achondroplasticpatient. Am J Orthod Dentofacial Orthop 1980; 96: 255-263.2. Hunter AGW, Bankier A, Rogers JG, Sillence D, Scott CI jun. Medical complications ofachondroplasia: a multicentre patient review. J Med Genet 1998; 35: 705-712.3. Wassman ER jun., Rimoin DL. Cervicomedullary compression with achondroplasia. J Pediatr1988; 113: 411.4. Lachman RS, Neurologic abnormalities in the skeletal dysplasias: a clinical and radiologicalperspective. Am J Med Genet 1997; 69: 33-43.5. Beighton P, Bathfield CA. Gibbal achondroplasia. J Bone Joint Surg Br 1981; 63: 328-329.6. Pedersen P. Roentgenographic cephalometric survey of cranial and facial structures in thehuman achondroplastic dwarf. Master of Science Thesis, University of Washington, 1970.7. Cohen MM jun., Walker GF, Phillips C. A morphometric analysis of the craniofacialconfiguration in achondroplasia. J Craniofac Genet Dev Biol (Suppl) 1985; 1: 139-165.ICD-10International Statistical Classification of Diseases and RelatedHealth Problems Volume 1, 2 and 3ICD-10 code source books are available from the South African Medical Association s (SAMA) Healthand Medical Publishing Group (HMPG) at very reasonable rates. HMPG is a recognised distribution agent of the World Health Organisation who publishes this compre-hensive set of ICD-10 codes. We have obtained a special discounted rate on this set, only available toSouth African doctors.The three-volume set contains all the codes and a tutorial on how to use the codes correctly. This bookset is a user-friendly quick reference guide that will help you gain the most benefit from the codes. To take advantage of this offer, contact HMPG s Book Department at Tel: (021) 530 6520Fax: (021) 531 4126 •  Or e-mail:books@samedical.orgVolume 1: Members: R1110.00Non-members: R1233.00Volume 2: Members: R  363.00 Non-members: R  408.00Volume 3: Members: R1110.00 Non-members: R1233.00CD-Rom now available complete codes + search facility: Members: R2217.00Non-members: R2469.00588-589 pgs  7/27/05  3:49 PM  Page 589

Orthodontic management of achondroplasia in South Africa

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Orthodontic management of achondroplasia in South Africa

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