Orthognathic Surgery in Pycnodysostosis: a Case Report

110 Herna´ndez-Alfaro et al. Case Report Congenital Craniofacial Deformities

F. Hernańdez-Alfaro1, J. Arenaz Bu´ a2, M. Serra Serrat3, Orthognathic surgery in J. Mareque Bueno1 1Department Oral and Maxillofacial Surgery Teknon Medical Center, Barcelona, Spain; pycnodysostosis: a case report 2Department of Oral and Maxillofacial Surgery, Complejo Hospitalario Universitario de A Corunã, Spain; 3Orthodontist, Barcelona, Spain F. Hernańdez-Alfaro, J. Arenaz Buá, M. Serra Serrat, J. Mareque Bueno: Orthognathic surgery in pycnodysostosis: a case report. Int. J. Oral Maxillofac. Surg. 2011; 40: 106–123. # 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Abstract. Pycnodysostosis is an extremely rare genetic osteosclerosis caused by cathepsin K deficiency. It is a human autosomal recessive genetic disorder characterized mainly by osteosclerosis of the skeleton due to decreased bone turnover. It is characterized by short stature, brachycephaly, short and stubby fingers, open cranial sutures and fontanelle, and diffuse osteosclerosis. Multiple fractures of the long bones and osteomyelitis of the jaw are frequent complications. The authors describe an 18-year-old girl with a clinical and radiological diagnosis of pycnodysostosis and the ortho-surgical treatment undertaken. Bimaxillary orthognathic surgery was carried out using rigid fixation and bone grafts. The authors recommend bimaxillary orthognathic surgery as a choice for treating the dentofacial deformities of pycnodysostosis, emphasizing the good and stable results Accepted for publication 19 July 2010 obtained in terms of facial aesthetics and occlusion. Available online 21 August 2010

Pycnodysostosis is a rare osteopetrotic nodysostosis are abnormally dense and narrowing of the airway1–3,5–7,10. Dental clinical entity. It belongs to the group of brittle as a result of this insufficient re- crowding, dental abnormalities and craniotubular bone dysplasias, first absorption process5,9. Pycnodysostosis is impaction are observed, as well as altera- described in 1962 by Maroteaux and Lamy usually diagnosed at an early age due to tions in eruption1–3,6. as a form of dwarfism with craniofacial the typical phenotype with proportionate The diagnosis of pycnodysostosis is pri- malformation similar to cleidocranial dys- dwarfism and peculiar facies1,3,5,6.The marily based on clinical features and radio- plasia1,5–7,10. The disease has also been diagnosis is sometimes made late, as a graphs, but the confirmatory test is a called Toulouse-Lautrec syndrome, after result of high susceptibility to long bone cathepsin K gene mutation analysis. Other the French artist Henri de Toulouse- fractures and infections, because of the uncommon clinical disorders of reduced Lautrec who suffered from the disease1. severe bone fragility resulting from bone resorption include osteopetrosis, osto- Pycnodysostosis has an autosomal reces- increased bone density and impaired genesis imperfecta, cleidocranial dysplasia sive inheritance1–10 and is characterized bone vascularity1–10. and idiopathic acroosteolysis1,5. In osteo- by systemic high bone density due to Extragnathic skeletal involvement petrosis, the bone marrow may be absent so decreased bone turnover1–7,9. In the includes short stature, clavicular and cra- hematopoietic alterations are common. 1990s, the defective gene responsible for niofacial dysplasia, total or nearly total Signs of compression of the cranial nerves pycnodysostosis was located in chromo- phalangeal dysplasia and generally radio- include facial paralysis, deafness or pain. some Iq21, offering accurate diagnosis, graphic osteosclerosis. The acromial ends Cleidocranial dysplasia may seem like pyc- carrier testing and a more thorough under- of the clavicles may be aplastic1,2,5. This nodysostosis because it presents with agen- standing of this disorder1,3,5–7,10. Pycno- syndrome usually presents with typical esis or clavicular aplasia, and alterations of dysostosis represents a lysosomal storage craniomaxillofacial deformities, such as the skeletal bone membranes, however, disease of the bone caused by a mutation a dolicocephalic or brachiocephalic skull bone density is not increased. In idiopathic in the gene that codes the enzyme with prominent forehead, hypoplastic acroosteolysis, the appearance of the cathepsin K. This protease plays a major maxilla and mandible with micrognathia, patients is typical, with hypotelorism, role in osteoclast-driven bone resorp- and hypoplastic midface with exophthal- exophthalmos, and an upturned nose but tion6,7,9,10 and is responsible for degrad- mus, hypopneumatization of the maxillary increased bone density is not present1,9. ing collagen type 1, which constitutes sinuses, beaked nose, open and anterior The choice of surgical technique was 95% of the organic bone matrix1,9.The cross-bite, obtuse mandibular angle, difficult because the high risk of infection, bones in individuals afflicted with pyc- grooved palate, longer soft palate and secondary fractures and nonunion render Orthognathic surgery in pycnodysostosis 111 the classical choices of distraction and tomies, xenografts and rigid fixation with Postoperative recovery was uneventful iliac bone graft hazardous10. There have osteosynthesis material, because of the high and the patient was discharged 48 h after been few reports of rigid fixation of such risk of infection and nonunion as a result of surgery. A post-surgical cone beam CT dysplasic bone in the craniomaxillofacial the poor bone quality. For that purpose, a scan revealed adequate repositioning of area4,7,8,10. The purpose of this paper is to vertical and sagittal augmentation genio- the bony segments. The patient followed report bimaxillary orthognathic surgery plasty was carried out under general a liquid diet for 10 days and then a soft diet and bone grafting for treating the dento- anaesthesia with 8 mm advancement for 2 months.The postoperative orthodon- facial deformities of pycnodysostosis, and 7 mm downgrafting with interposi- tics lasted for 12 months and yielded a emphasizing the good and stable results tion of a bovine hydroxyapatite block functional class I occlusion with stable obtained in terms of facial aesthetics and (Bioss). Postoperative recovery and heal- periodontal parameters. A cone beam occlusion. ing was uneventful. scan, 24 months post-surgery, revealed After 14 months of presurgical ortho- stability of skeletal movements and ade- dontics the patient was considered ready quate consolidation at the osteotomies. Case report for bimaxillary surgery. The orthodontist Patient satisfaction with facial and occlu- The authors present the case of an 18- used skeletal anchorage to aid levelling. sal results was very high. As a result of her year-old girl who had been clinically and The preoperative work up included a cone high satisfaction level, orthodontics is still radiographically diagnosed with pycno- beam CT and conventional model surgery in progress due to low cooperation from dysostosis and referred to them for treat- with the generation of two surgical splints. the patient after surgery. She was able to ment. The cathepsin K gene mutation Surgery was performed under hypoten- resume her social life, which had been test was performed and confirmed the sive general anaesthesia. The chin plate was severely compromised (Fig. 2). presence of the disease. removed at the time of orthognathic surgery The patient’s main complaints were her and excellent bone healing was observed. A facial appearance, occlusal alterations and mandibular advancement of 13 mm with Discussion snoring. Physical examination revealed a bilateral sagittal split osteotomies was per- severely distorted face as a result of ante- formed. A Le Fort I osteotomy followed Pycnodysostosis is a rare autosomal reces- roposterior and vertical maxillary and with maxillar advancement of 10 mm and sive disease. The incidence is estimated to mandibular hypoplasia. A severe short downgrafting of 8 mm. Rigid fixation was be 1.7 per 1 million births1,2,5,10. Multiple face was accompanied by a relative rhi- achieved with four miniplates in the max- fractures of long bones and osteomyelitis, nomegaly. A class II occlusion was pre- illa and four more in the mandible. Two stridorous breathing and snoring due to a sent (Fig. 1). Other findings included short plates on each mandibular osteotomy were narrow chest and airway are frequent com- 5,6,10 6 stature and clavicular and phalangeal dys- used to hold the advancement and to pro- plications .MUTO et al. reported pyc- plasia. A cone beam CT scan revealed vide enough stability. Interpositional nodysostosis presenting as severe snoring, severely distorted facial architecture with blocks of Bioss were placed in the gaps caused by pharyngeal narrowing in two abnormally small facial bones. both at the Le Fort I and the sagittal split. An siblings. Cephalograms3,6 showed pharyn- Treatment began with fixed orthodon- open reduction rhinoplasty with dorsal, alar geal narrowing at the level of the soft tics to achieve enough alignment to allow and septal reduction was performed. No palate and the base of the tongue caused for further orthognathic surgery. postoperative intermaxillary fixation was by the long soft palate and mandibular Test surgery was carried out to evaluate applied apart from two light box elastics hypoplasia. They suggested that respira- the patient’s bone response to facial osteo- to guide mandibular movements. tory insufficiency, such as snoring or

Fig. 1. Clinical examination. (A) Frontal view and (B) lateral view, revealed a severely distorted face because of anteroposterior and vertical maxillary and mandibular hypoplasia. A severe short face was accompanied by a relative rhinomegaly. A class II occlusion was present. 112 Herna´ndez-Alfaro et al.

verified by a cone beam CT scan. Neither the authors nor the patient encountered any problems during treatment. The long-term stability of the achieved occlusion and facial appearance confirm that adequate healing in such sclerotic bone is to be expected using standard fixation. From the literature3,6 and their results, the authors suggest that respiratory insufficiency, such as snoring or obstructed sleep apnoea, are common and under-appreciated symptoms of pycnodysostosis, and bimaxillary advancement may be beneficial. In conclusion, patients affected with pycnodysostosis with severe malocclu- sions and upper airway and aesthetic com- promise may be treated with bimaxillary orthognathic surgery successfully. This patient remained stable for at least 2 years after surgery. The surgical technique is hazardous because of the high risk of Fig. 2. Views 24 months after surgery. (A) Clinical frontal and (B) lateral views. The aesthetic facial results were very high and allowed the patient to resume her social life, which had been infection and nonunion healing, but severely compromised. bimaxillary orthognathic surgery may be a better choice for achieving successful and stable aesthetic and functional results. obstructed sleep apnoea, are common and orthopaedic problem for surgical correction under-appreciated symptoms of pycnody- in this condition is the recurrent pathologi- Competing interests sostosis3,6. The maxillary hypoplasia often cal fracture of bones and the high infection results in a class III occlusal relationship rates, due to the limited quality and vascu- None declared. with characteristic retrusion, and vertical larity of the sclerotic bone1,2,5–8,10.These 3,7 reduction of the midface . The body of facts represent a challenge for the maxillo- Funding the mandible also presented a generalized facial surgeon. A case report of a successful reduction in size, which could be appre- conventional Le Fort I osteotomy was pre- None. 8 ciated more by Go-Me measurements, sented by POLLEY and FIGUEROA . The size leading to the belief that the maxilla would of surgical movement was smaller, they be more involved in the development of performed only monomaxillar surgery Ethical approval the significantly unfavourable skeletal and there was no need for bone grafting8. Not required. 3 7 sagittal pattern of these patients . NØRHOLT et al. performed maxillary dis- Bone fragility and a history of frequent traction for a 15-year-old girl with pycno- fractures may suggest a diagnosis of dysostosis who presented with severe References abnormalities in the material composition dentofacial deformity. They reported stable Alves Pereira Berini Ayte´s Gay 5,9 1. D, L, and structure of bone . Tooth extraction, consolidation was only obtained 13 months Escoda C. Pycnodysostosis. A report of 3 in patients who suffer from pycnodysos- after Le Fort I osteotomy followed by 6 clinical cases. Med Oral Pathol Oral Cir tosis, requires special care, such as carry- weeks of external distraction. Buccal 2008: 13: E633–E635. 10 ing out the surgery as atraumatically as TEISSIER et al. , reported the case of a 3- 2. Bathi RJ, Masur VN. Pycnodysosto- possible and with proper asepsis, due to year-old boy with pycnodysostosis who sis—a report of two cases with a brief the risk of fracture, especially in the mand- presented with severe snoring as a result review of the literature. Int J Oral Max- ible. The impaired bone vascularity, of pharyngeal narrowing due to a hypoplas- illofac Surg 2000: 29: 439–442. Fonteles Chaves Da increases the probability of developing tic mandible. They performed a bilateral rib 3. CS, Jr CM, Silveira A, Soares EC, Couto JL, post-extraction osteomyelitis1. Treatment graft to correct the micrognathia and to De Azevedo Mde F. Cephalometric of osteomyelitis of the jaws in pycnody- allow enlargement of the pharynx by acting characteristics and dentofacial abnormal- sostosis is difficult and may lead to large on an anterior projection of the chin and a ities of pycnodysostosis: report of four 2,7 resections . decrease of the glossoptosis. A significant cases from Brazil. Oral Surg Oral Med No information is available in the litera- reduction in snoring and an excellent mouth Oral Pathol Oral Radiol Endod 2007: 104: ture regarding the efficacy and safety of aperture were obtained. They stated that E83–E90. orthodontics in children or young adults this risk-limited (compared with free fibu- 4. Kato H, Matsuoka K, Kato N, with pycnodysostosis3. Orthodontic and lar or iliac flap) surgical technique is ideal Ohkubo T. Mandibular osteomyelitis orthopaedic movements are dependent on for patients presenting a high risk of infec- and fracture successfully treated with osteoclastic activity and bone resorption tion, nonunion and secondary fracture (par- vascularised iliac bone graft in a patient with pycnodysostosis. Br J Plast Surg and remodeling capacities. Few cases of ticularly if a fibular free flap was obtained) 10 2005: 58: 263–266. elective skeletal facial surgery in pycnody- after such a surgical procedure . In the Mujawar Naganoor Patil 7,8,10 5. Q, R, H, sostosis have been reported and there reported case, plates and screws achieved Thobbi AN, Ukkali S, Malagi N. are few reports of rigid fixation in dysplasic enough stability and allowed uneventful Pycnodysostosis with unusual findings: facial bones4,7,8,10. The most important bone healing. The osseous healing was a case report. Cases J 2009: 23: 6544. Orthognathic surgery in pycnodysostosis 113

6. Muto T, Yamazaki A, Takeda S, Tsuji nal distraction. Atlas Oral Maxillofac ted with a bilateral rib graft. Cleft Palate Y, Shibata T. Pharyngeal narrowing as a Surg Clin North Am 1999: 7: 15. Craniofac J 2009: 46: 93–96. common feature in pycnodysostosis—a 9. Soliman AT, Ramadan MA, Sherif A, cephalometric study. Int J Oral Maxillo- Aziz Bedair ES, Rizk MM. Pycnody- Address: fac Surg 2005: 34: 680–685. sostosis: clinical, radiologic, and endo- Jorge Arenaz Bu´a 7. Nørholt SE, Bjerregaard J, Mose- crine evaluation and linear growth after As Xubias s/n kilde L. Maxillary distraction osteogen- growth hormone therapy. Metabolism 15008 La Corun˜a esis in a patient with pycnodysostosis: a 2001: 50: 905–911. Spain case report. J Oral Maxillofac Surg 2004: 10. Teissier N, Jacquemont ML, Blancal Tel.: +34 676200787 62: 1037–1040. JP, Elmaleh-Berge`s M, Van Den E-mail: [email protected] 8. Polley JW, Figueroa AA. Maxillary Abbeele T, Bennaceur S. Severe snor- distraction osteogenesis with rigid exter- ing in a child with pycnodysostosis trea- doi:10.1016/j.ijom.2010.07.006

Case Report Dental Implants

T. Shirota1, O. Shimodaira2, Y. Matsui3, M. Hatori1, S. Shintani1 Zygoma implant-supported 1 Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan; 2Department of prosthetic rehabilitation of a Geriatric Dentistry, School of Dentistry, Showa University, Tokyo, Japan; 3Department of Oral and Maxillofacial Surgery, Yokohama City patient with a maxillary defect University Graduate School of Medicine, Yokohama, Japan

T. Shirota, O. Shimodaira, Y. Matsui, M. Hatori, S. Shintani: Zygoma implant- supported prosthetic rehabilitation of a patient with a maxillary defect. Int. J. Oral Maxillofac. Surg. 2011; 40: 106–123. # 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Abstract. This clinical report describes the successful management of a patient who underwent extensive resection of a maxillary cancer, by introduction of a maxillary obturator prosthesis using zygoma implants. The patient was a 57-year-old man with cancer of the upper anterior gingiva. The maxillary bone in the affected region had been extensively excised by radical surgery. Owing to loss of teeth retaining the denture, the existing prosthesis was unstable, and the patient experienced severe speech and mastication disorders. Four zygoma implants (two on each side), and two conventional dental implants (one each at both maxillary tuberosities) were used as denture retainers. The obturator prosthesis was stabilized by the implants, and the patient’s oral function improved. High-level compatibility between the implant and surrounding tissue was obtained by mucosal regeneration around the implant. The results suggest that the combination of zygoma and conventional dental implants improves postoperative oral function by facilitating retention of the Accepted for publication 19 July 2010 obturator prostheses. Available online 21 August 2010

Severe maxillary defects resulting from improve the stability and retention of max- tional dental implants can be placed, and surgical resection of oral neoplasms are illofacial prosthetic obturators and to extensive loss of soft tissues including the associated with major difficulties in restor- restore oral function1,3. Implant placement gingiva, mucosa and muscle. ing oral function, such as mastication, and the subsequent prosthetic treatment The zygoma implant was developed for speaking and swallowing, and impaired often become difficult following resection edentulous patients with insufficient bone facial esthetics. In such cases, conven- of maxillary cancer because of a lack of mass for dental implants5. This implant is tional dental implants have been used to bone tissue in the areas where conven- fixed in the zygoma so it is considered