British Journal of Oral Surgery (1976),
PYCNODYSOSTOSIS-A
13, 254-263
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COMPLICATING
A. E. GREEN,M.B., B.S., F.D.S., R.C.S.(Eng.)l N. L. ROWE, F.R.C.S., F.D.S., R.C.S.
and
Westminster Hospital, Teaching Group, London SWI
Summary. A case of pycnodysostosis is presented and the differential diagnosis discussed. The complications arising from tooth extraction are described along with the complications which beset subsequent surgery. The authors postulate reasons for the difficulties encountered. The literature is reviewed.
INTRODUCTION VARIATIONS of cleidocranial dysostosis and osteopetrosis have been recognised for many years (Ehnore, 1967). Maroteaux and Lamy (1962) reported consistent variations of these disorders which were felt to be sufficiently characteristic to constitute a new syndrome which they termed pycnodysostosis. Elmore (1967) reviewed 33 atypical cases of cleidocranial dysostosis and osteopetrosis which he considered fulfilled the criteria of pycnodysostosis as described by Maroteaux and Lamy, the earliest case having been described initially by Montanari (1923), as an unusual case of achondroplasia. Sedan0 et al. (1968) claim to have found 73 cases of pycnodysostosis in the world literature; of these, 33 had already appeared in Elmore’s series. Collado-Otero (1956) accurately described the syndrome but did not assign to it a specific name. Maroteaux and Lamy (1965) produced evidence indicating that Toulouse-Lautrec suffered from this condition.
Clinical Features. The physical findings characteristic of the syndrome consist of dwarfism, with relatively reduced arm span compared with the crown to heel height, the majority of reported cases being under 5 feet tall (Fig. I). The head is relatively large comRacial distribution appears to be non-specific. pared with the rest of the body, and there is frequently frontal and parietal bossing with palpable sutures sometimes associated with patency of the fontanelles. The face is generally small, due to hypoplasia of the facial bones, giving an appearance of proptosis, and the mandibular angle is obtuse. Intra-oral findings consist of a high arched palate with, in some cases, a failure of the deciduous teeth to resorb and exfoliate. The teeth appear to erupt at the correct time, but failure of exfoliation produces crowding, often with a persistent deciduous dentition, leading to a double row of teeth. Received 8.8.75.
Accepted 12.8.75
l Present address: Department of Oral Surgery, University School, Mortimer Street, London, WI.
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I
Two
A, A case published by Dr Stanley Elmore patients suffering from pycnodysostosis. (Fig. IA by courtesy of Dr Stanley with, B, a case presented in this paper for comparison. Elmore and the Journal of Bone and Joint Surgery.)
The clavicles are generally present, but frequently aplastic at the acromial ends. There is often a kyphosis or scoliosis. The hands and feet have shortened phalanges and, on occasions, the distal phalanges are absent. Long bones are bowed; this is seen particularly in the legs and is probably the result of repeated fractures. Radiographic Findings. The most important radiographic feature is increased radio-density of the entire skeleton, which has been reported in all of Elmore’s cases. The skull is large and brachycephalic and, as previously mentioned, open fontanelles may be visible. Cranial sutures are frequently separated, even in the adult; facial bones are hypoplastic with small orbits set close together, and the paranasal sinuses are underdeveloped. Spinal abnormalities are common, particularly vertebral fusion. In the long bones, the medullary cavities are poorly defined but still visible, and there may In the forearm, curvature of the radius and ulna be evidence of old fractures. may be observed together with tapering of the phalanges and absence of ungual tufts. Laboratory Investigations. These are reported as being within normal limits by Elmore in his review of the literature. Microscopic Features. The histological appearance of bone supports the
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radiographic findings in that there is dense cortical bone of normal architecture, with a small medullary cavity, but there is evidence of active haemopoiesis. Hereditary Factors. In seven of Elmore’s cases, there is a clear history of consanguineous marriage, which supports the views of Maroteaux and Lamy that the syndrome is transmitted by an autosomal recessive trait, and they report two cases of pycnodysostosis in children of normal parents, again tending to support the recessive nature of the condition. Apley (1969) is in agreement with this suggestion, and Emami-Ahari et al. (1969) report a case arising from normal parents who were first cousins. Chromosome investigations carried out on two reported cases showed no significant abnormality. In a case reported by Giaccai et al. (Ig54), the patient was also mentally retarded but this was thought to be a familial trait rather than one specifically related to the syndrome. CASE REPORT A 42-year-old Libyan male was referred in 1974 following exfoliation into the The history was that, in 1967, following mouth of a chrome-cobalt mandibular prosthesis. the extraction of a right lower first molar tooth, the jaw had been fractured and osteomyelitis became established. This eventually necessitated resection of the mandible from anterior to the lower right second molar tooth to the opposite angle, and the insertion of a prosthesis. This was performed in Rome in the same year. When first examined at the Westminster Hospital, it was noted that the prosthesis was exfoliating into the mouth in its entirety and that pus was draining from bilateral submandibular sinuses. Initial radiography revealed the extent and morphology of the chrome-cobalt prosthesis, and indicated infection surrounding the bone ends of the mandible. An unusual increased bone density was also noted on the skull films and with this feature in mind, further radiological examinations were carried out. Chest X-ray revealed normal soft tissue outlines, but a number of healed rib fractures were apparent, and it was observed that the ends of the clavicles were underdeveloped. The tibiae The lumbar spine showed increased density of the vertebral end plates. were abnormally dense, showed a failure of normal trabeculation and healed fractures were noted bilaterally. The bones of the hands and feet were short and showed a marked increase in bone density with evidence of acrolysis (Figs. 2 and 3). A diagnosis of pycnodysostosis was made purely on radiological grounds. Routine chemical pathology, liver function and haematology investigations were all within normal limits. Treatment. Initial treatment consisted of antibiotics to control the infection followed by removal of the exfoliating prosthesis, which was performed intra-orally but only with considerable difficulty, due to the dense fibrosis which had taken place around it. Mucosal coverage of bone ends was obtained, and a tracheostomy was performed to ensure patency of the airway. Following removal of the prosthesis, the sepsis slowly settled but 6 weeks elapsed before the patient was fit for reconstruction. Using an extra-oral incision extending forward from both submandibular regions to meet in the midline, a plane was opened with difficulty into which it was intended to insert a silastic edged perforated titanium tray-the dimensions of which had been planned from the radiographs. Th is was secured to the bone ends with titanium screws and the body of the tray was filled with caucellous bone obtained from the iliac crest. With the tray positioned, three-layer closure was employed and at the end of the procedure, In the post-operative phase, massive oedema the oral mucous membrane was intact. of the tongue, lips and submandibular tissues developed which proved to be very slow
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FIG. 2 Radiological appearances of the tibiae and hands of the case presented. Note the uniform increase of bone density although medullary cavities are still visible. Deformity due to fractures is also obvious. In the hands~~l~~;tof the terminal tufts of the phalanges is
FIG. 3 Skull radiographs of the case presented. Note the increased bone density and the absence of frontal and maxillary sinuses. The nasal cavities are underdeveloped giving a narrow face with close set orbits.
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FIG.
4
A, The patient after the first reconstructive
attempt showing massive oedema of the tongue.‘@ i
B, A plaster model of the patient’s upper ridge alongside an average size edentulous upper model indicating the gross underdevelopment of the maxilla. j
in subsiding (Fig. 4, A). Apart from the oedema, the initial progress was satisfactory but, by the 12th post-operative day, the originally intact oral mucosa had broken down from anterior to the standing lower right first molar to the midline. Bone chips were exfoliating into the mouth. At this stage, it was apparent that the body of the titanium tray was too wide to be accommodated by the tissues and that the head of one of the screws on the right side was prominent. Two weeks following the insertion of the tray, it was decided that the remaining two lower teeth-namely lower right first and second molars-should be extracted, the offending screw replaced in a more suitable position and the tray refilled with bone. This was performed through an intra-oral approach and, prior to being refilled with diced rib graft, the body of the tray was narrowed by bending of the flanges. The intra-oral wound was closed in two layers. This procedure resulted in a further increase of the oedema and, by the fifth postoperative day, a frank left submandibular abscess had developed, which required extraoral drainage. The pus contained necrotic bone chips. Following drainage of the day, oral abscess, the patient’s condition improved, but by the 12th post-operative breakdown had occurred once more in the right buccal sulcus. Initially, this was limited and it was felt that spontaneous healing may occur, but at 7 and IO weeks post-operatively, small intra-oral procedures were carried out in an attempt to re-establish mucosal cover. On both occasions, local modifications were made to the tray by bending in an attempt to reduce its bulk. Even after this period of time, the oedema was still gross, but showing signs of resolution. The second attempt at closure appeared to have given good results but, once more, intra-oral breakdown occurred within 4 weeks. By now, it had become apparent that this approach to reconstruction was a failure and a decision was made to remove the titanium tray and insert a Bowerman-Conroy titanium bar prosthesis. It was only at this time-4 months following the first major reconstructive attempt-that the oedema had settled sufficiently to allow this second approach to be made. Through bilateral submandibular incisions, the titanium tray was removed and the Bowerman-Conroy bar was tunnelled through the intervening tissue in the midline. The bar was secured by two titanium screws to each bone fragment.
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The patient’s final appearance at
the
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5
completion of surgery, after resolution of the oedema.
Great difficulty was encountered in creating a plane for insertion of the bar with neutral soft tissue tension due to the extreme degree of fibrosis present, and the total absence of normal soft tissue planes. Careful closure in layers was carried out. Initial post-operative progress was encouraging but, as on the previous occasion, surgery produced considerable oedema which fortunately was less severe and showed signs of settling more rapidly. Mucosal breakdown within the mouth was first noticed on the 10th post-operative day, when one of the carefully repaired areas of intra-oral dehiscence broke down once more. This occurred in the right premolar region and after only a few days, it was obvious that purulent saliva was forming in a sump around Fashioning of the titanium bar the prosthesis and further breakdown was occurring. had been a considerable problem in the first instance due to the lack of any normal jaw to act as a guide to contour. As the oedema subsided, it became apparent that the bar inserted was too tight around the base of the tongue and this was felt to be a contributory factor to dehiscence. Eighteen days after the insertion of the first Bowerman-Conroy bar, it was removed This procedure was carried out through and a bar of more generous proportions inserted. bilateral submandibular incisions, the longer bar being placed at a much deeper level in the mass of fibrous tissue that had replaced the submandibular and sublingual tissues. Intra-oral areas of breakdown were repaired. Oedema once again was a post-operative problem, but showed signs of earlier resolution. Following this operation, initial encouraging post-operative progress was maintained for the first time, and breakdown Six weeks after insertion, radiographs did not occur either intra-orally or extra-orally. indicated that the two retaining screws on the left side had pulled loose and they were accordingly replaced by bolts through an extra-oral incision. Nine weeks after insertion of the second titanium bar, the mucosa was still intact
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and it was felt that the tracheostomy should be allowed to close-8 months after its creation. As the oedema continued to subside, it was apparent that the facial musculature was still capable of functioning and, although the facial nerve branches had never been identified amongst the dense scar tissue, innervation was intact and lip seal returned. Fluid intake was maintained intravenously in the post-operative periods, but oral fluids and fluid diet were encouraged as early as possible. Nasogastric feeding was resorted to whilst the oedema was gross, but once recovery was underway, tolerance of the nasogastric tubes was poor and they were frequently removed by the patient. All major surgery was covered by antibiotics-ampicillin and flucloxacillin being used. Only on one occasion was acute infection a problem and this resolved following drainage of a submandibular abscess. Infection was otherwise not a problem; the frequent, although inconsistent, positive cultures being probably the result of tissue breakdown associated with the exposure of a foreign body rather than the primary cause. As, the patient continued to improve, it became possible to construct a full upper denture which was well retained, despite the diminutive ridge (Fig. 4, B). He was advised against the construction of a lower denture at any time, in view of the ever present possibility of pressure necrosis of the poor quality tissues overlying the mandibular prosthesis. The patient’s final appearance is shown in Figure 5. DISCUSSION The diagnosis of pycnodysostosis was made radiologically and, as in Elmore’s cases, the most striking features are seen in the radiographs; the generalised increased radiodensity of the skeleton being a prime diagnostic feature. The patient had brachycephaly but, unlike many of the reported cases, the cranial sutures and fontanelles were closed. The maxillae were extremely hypoplastic, as can be seen in the radiographs and from the upper dental model. Antra were small and the frontal sinuses virtually absent. Mandibular development was impossible to assess in view of the gross nature of the disease process. Increased radiodensity of the vertebral end plates was apparent, but vertebral fusion was not noted. Medullary cavities in the limbs were ill-defined and multiple healed fractures of the tibiae were visible. Phalanges were tapered with lysis of the terminal tufts. Hypoplasia of the clavicles was noted along with evidence of healed rib fractures. The physical findings bore a striking resemblance to those described by Ehnore, particularly with regard to the physique and facial appearance. The normality of laboratory investigations is another feature worth noting. Bone biopsies taken at the time of operation showed dense bone of otherwise normal architecture (Fig. 6). Chromosome studies were not undertaken. There was no evidence of mental retardation. Fractures of the mandible during tooth extraction have been reported in three cases of pycnodysostosis by Blasi (Ig37), Krabbe (1950) and Lievre et al. (Ig64), but no comment is made regarding their progress. In a fourth case reported by Emami-Ahari et al. (1969) the fracture is recorded as having been treated by sequestrectomy and curettage but the outcome is not stated. The abnormal density of the bone, would seem, however, to make osteomyelitis a very real danger in such circumstances. Fractures of the mandible and osteomyelitis are reported to be common sequelae of tooth extraction in patients suffering from osteopetrosis, because of the increased bone density and the reduction of the medullary spaces
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FIG. 6 Hiistological appearance of bone specimens taken during surgery. A, x40. B, x (H. & E.) Note the dense Haversian systems of otherwise normal architecture.
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(Shafer et al.,
BRITISH 1974).
Inpycnodysostosis,
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with cleidocranial dysostosis, there is no such association. uncomplicated fractures are reported to heal normally (Elmore,
1967). Important features that differentiate pycnodysostosis from osteopetrosis are the presence of a demonstrable medullary cavity in the long bones in pycnodysostosis and the presence of active medullary haemopoiesis. There is no anaemia or hepatosplenomegaly that would suggest extra-medullary haemopoiesis. Anaemia may be progressive in osteopetrosis, thus reducing life expectancy, but this is not a feature of pycnodysostosis. The stature of sufferers from osteopetrosis is generally normal and tapering phalanges and ungual tuft lysis are not consistent findings. Cleidocranial dysostosis and pycnodysostosis are both associated with patent fontanelles, separated sutures, deficient clavicles and abnormalities of dental eruption and resorption. Dense, fragile bones, however, are not a feature of cleidocranial dysostosis, neither are tapering phalanges and the absence of ungual tufts. Cleidocranial dysostosis is inherited as an autosomal dominant characteristic, whereas the inheritance of pycnodysostosis appears to be an autosomal recessive trait. Englemann’s disease or progressive diaphyseal dysplasia is a condition associated with increased bone density, but patients with this disorder are tall with abnormally long limbs. They are normal in infancy and the characteristic changes do not The skull is not involved and shows become apparent until well into childhood. none of the characteristic changes of pycnodysostosis. Idiopathic non-familial acre-osteolysis is a rare condition combining lysis of the terminal phalanges, separation of the cranial sutures and frequent fractures. However, skeletal radiodensity is not a feature of this condition. Skeletal fluorosis is another cause of generalised skeletal radiodensity, but bone fragility is not a feature of this condition (Hunter, 1964). Calcification of ligaments and tendons occurs in fluorosis and this is radiologically demonstrable. This is a feature not present in pycnodysostosis. Osteopoikilosis (Duthie & Ferguson, 1973) is a rare condition producing patchy skeletal sclerosis, whereas, in pycnodysostosis, the sclerosis is diffuse. This case presented some unusual problems that warrant further consideration. The dense nature of the bone obviously makes dental extraction a hazard from the point of view of jaw fracture and subsequent infection, as already The reconstructive difficulties were compounded by the gross nature mentioned. of the jaw defect and the dense fibrosis that had resulted from chronic infection and previous surgery, thus preventing an accurate estimate of the original jaw The resultant lack of tissue planes made dissection difficult and gave contour. no assistance in determining a suitable plane or contour for the prostheses inserted. The original titanium tray prosthesis is a case in point and in retrospect it was apparent that the tray was too wide to be accommodated within the tissues. The oral mucosa became tented or stretched across the width of the tray, and this factor, together with some degree of unavoidable dead space, made breakdown almost inevitable even with the metal edges protected with silastic. Attempts to narrow the tray by bending the flanges in situ were fruitless because, although the width was reduced, the dead space was increased. Bone used in the reconstructive attempts was probably abnormal, as it was autogenous. This may well have predisposed to failure of the grafts and the
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of post-operative infection in one instance. Another possible cause of frequent wound breakdown was thought to be the abnormal bone turnover, and it is postulated by the authors that normal osteoclastic action is probably necessary to ‘etch’ the bone surface to allow the attachment of fibrous tissue associated with healing and repair. Post-operative oedema was a notable problem during the reconstructive Following insertion of the titanium tray prosthesis, gross oedema of surgery. the lips and tongue persisted for 8 weeks. It is considered that this was due to obstruction of the lymphatic and venous drainage arising from a combination of bilateral extra- and intra-oral incisions, gross fibrosis from previous surgery, and mechanical constriction of the base of the tongue by the titanium tray. This was a problem that persisted during his stay of 9 months, but there was a gradual improvement as time passed. The gross oedema underlined once more the value of the initial tracheostomy.
onset
ACKNOWLEDGEMENTS 8ur thanks are extended
to Dr F. Starer, Consultant Radiologist, at the Westminster Hospital, who originally made the radiological diagnosis and to Professor A. D. Morgan, who performed the histological examinations. We are also indebted to the stafl of the Photographic Department of the Westminster Hospital, for their excellent illustrations, and to Miss Jill We wish to acknowledge our appreciation Mountain for her services in the typing of this paper. of the assistance of Mr John Williams, Senior Registrar, at the commencement of this patient’s treatment. Especial thanks are extended to Dr Stanley Elmore for permitting the use of one of his illustrations in this paper.
REFERENCES APLEY, A. G. (1969). Recent Advances in Orthopaedics. London: Churchill. BLASI, R. (1937). Radiologica Medica, 24, 741. COLLADO-QTERO, F. (1956). Acta Pediatrica Espanola, 14, I. DUTHIE, B. D. & FERGUSON, A. B. (1973). Mercers Orthopaedic Surgery. London: Arnold. ELMORE,S. M. (1967). Journal of Bone and Joint Surgery, 49-A, 153. EMAMI-AHARI, Z., ZARABI, M. & JAVID, B. (1969). Journal of Bone and Joint Surgery, 51B,
307. GIACCAI,L., SALAAM,M. & ZELLWEGER, H. (1954). Acta Radiologica, 41, 417. The Diseases of Occupations, London: English Universities Press. HUNTER, D. (1964). KRABBE,K. H. (1950). Folia Psychiatrica, Neurologica, Neurochirurgica Neerlandica, 53, 328. Revue Rhumatisme, 31, 282. LIEVRE, J-A., CHADUT, A. & CAMUS, J. P. (1964). _MAROTEAUX, P. & LAMY, M. (1962). Archives FranGaises de Pediatrie, 19, 267. J ournal of the American MAROTEAUX, F. & LAMY, M. (1965). Medical Association,
191,
715. Chirurgia Organi Movimento, 7, 379. MONTANARI, U. (1923). SEDANO, H. D., GORLIN, R. J. & ANDERSON, V. E. (19%). American Journal of Diseases of Children, 116, 70. SHAFER, W. G., HINE, M. K. & LEVY, B. M. (1974). A Textbook of Oral Pathology.
Philadelphia and London: Saunders.
1313-D
PYCNODYSOSTOSIS-A
13, 254-263
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COMPLICATING
A. E. GREEN,M.B., B.S., F.D.S., R.C.S.(Eng.)l N. L. ROWE, F.R.C.S., F.D.S., R.C.S.
and
Westminster Hospital, Teaching Group, London SWI
Summary. A case of pycnodysostosis is presented and the differential diagnosis discussed. The complications arising from tooth extraction are described along with the complications which beset subsequent surgery. The authors postulate reasons for the difficulties encountered. The literature is reviewed.
INTRODUCTION VARIATIONS of cleidocranial dysostosis and osteopetrosis have been recognised for many years (Ehnore, 1967). Maroteaux and Lamy (1962) reported consistent variations of these disorders which were felt to be sufficiently characteristic to constitute a new syndrome which they termed pycnodysostosis. Elmore (1967) reviewed 33 atypical cases of cleidocranial dysostosis and osteopetrosis which he considered fulfilled the criteria of pycnodysostosis as described by Maroteaux and Lamy, the earliest case having been described initially by Montanari (1923), as an unusual case of achondroplasia. Sedan0 et al. (1968) claim to have found 73 cases of pycnodysostosis in the world literature; of these, 33 had already appeared in Elmore’s series. Collado-Otero (1956) accurately described the syndrome but did not assign to it a specific name. Maroteaux and Lamy (1965) produced evidence indicating that Toulouse-Lautrec suffered from this condition.
Clinical Features. The physical findings characteristic of the syndrome consist of dwarfism, with relatively reduced arm span compared with the crown to heel height, the majority of reported cases being under 5 feet tall (Fig. I). The head is relatively large comRacial distribution appears to be non-specific. pared with the rest of the body, and there is frequently frontal and parietal bossing with palpable sutures sometimes associated with patency of the fontanelles. The face is generally small, due to hypoplasia of the facial bones, giving an appearance of proptosis, and the mandibular angle is obtuse. Intra-oral findings consist of a high arched palate with, in some cases, a failure of the deciduous teeth to resorb and exfoliate. The teeth appear to erupt at the correct time, but failure of exfoliation produces crowding, often with a persistent deciduous dentition, leading to a double row of teeth. Received 8.8.75.
Accepted 12.8.75
l Present address: Department of Oral Surgery, University School, Mortimer Street, London, WI.
254
College Hospital, Dental
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I
Two
A, A case published by Dr Stanley Elmore patients suffering from pycnodysostosis. (Fig. IA by courtesy of Dr Stanley with, B, a case presented in this paper for comparison. Elmore and the Journal of Bone and Joint Surgery.)
The clavicles are generally present, but frequently aplastic at the acromial ends. There is often a kyphosis or scoliosis. The hands and feet have shortened phalanges and, on occasions, the distal phalanges are absent. Long bones are bowed; this is seen particularly in the legs and is probably the result of repeated fractures. Radiographic Findings. The most important radiographic feature is increased radio-density of the entire skeleton, which has been reported in all of Elmore’s cases. The skull is large and brachycephalic and, as previously mentioned, open fontanelles may be visible. Cranial sutures are frequently separated, even in the adult; facial bones are hypoplastic with small orbits set close together, and the paranasal sinuses are underdeveloped. Spinal abnormalities are common, particularly vertebral fusion. In the long bones, the medullary cavities are poorly defined but still visible, and there may In the forearm, curvature of the radius and ulna be evidence of old fractures. may be observed together with tapering of the phalanges and absence of ungual tufts. Laboratory Investigations. These are reported as being within normal limits by Elmore in his review of the literature. Microscopic Features. The histological appearance of bone supports the
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radiographic findings in that there is dense cortical bone of normal architecture, with a small medullary cavity, but there is evidence of active haemopoiesis. Hereditary Factors. In seven of Elmore’s cases, there is a clear history of consanguineous marriage, which supports the views of Maroteaux and Lamy that the syndrome is transmitted by an autosomal recessive trait, and they report two cases of pycnodysostosis in children of normal parents, again tending to support the recessive nature of the condition. Apley (1969) is in agreement with this suggestion, and Emami-Ahari et al. (1969) report a case arising from normal parents who were first cousins. Chromosome investigations carried out on two reported cases showed no significant abnormality. In a case reported by Giaccai et al. (Ig54), the patient was also mentally retarded but this was thought to be a familial trait rather than one specifically related to the syndrome. CASE REPORT A 42-year-old Libyan male was referred in 1974 following exfoliation into the The history was that, in 1967, following mouth of a chrome-cobalt mandibular prosthesis. the extraction of a right lower first molar tooth, the jaw had been fractured and osteomyelitis became established. This eventually necessitated resection of the mandible from anterior to the lower right second molar tooth to the opposite angle, and the insertion of a prosthesis. This was performed in Rome in the same year. When first examined at the Westminster Hospital, it was noted that the prosthesis was exfoliating into the mouth in its entirety and that pus was draining from bilateral submandibular sinuses. Initial radiography revealed the extent and morphology of the chrome-cobalt prosthesis, and indicated infection surrounding the bone ends of the mandible. An unusual increased bone density was also noted on the skull films and with this feature in mind, further radiological examinations were carried out. Chest X-ray revealed normal soft tissue outlines, but a number of healed rib fractures were apparent, and it was observed that the ends of the clavicles were underdeveloped. The tibiae The lumbar spine showed increased density of the vertebral end plates. were abnormally dense, showed a failure of normal trabeculation and healed fractures were noted bilaterally. The bones of the hands and feet were short and showed a marked increase in bone density with evidence of acrolysis (Figs. 2 and 3). A diagnosis of pycnodysostosis was made purely on radiological grounds. Routine chemical pathology, liver function and haematology investigations were all within normal limits. Treatment. Initial treatment consisted of antibiotics to control the infection followed by removal of the exfoliating prosthesis, which was performed intra-orally but only with considerable difficulty, due to the dense fibrosis which had taken place around it. Mucosal coverage of bone ends was obtained, and a tracheostomy was performed to ensure patency of the airway. Following removal of the prosthesis, the sepsis slowly settled but 6 weeks elapsed before the patient was fit for reconstruction. Using an extra-oral incision extending forward from both submandibular regions to meet in the midline, a plane was opened with difficulty into which it was intended to insert a silastic edged perforated titanium tray-the dimensions of which had been planned from the radiographs. Th is was secured to the bone ends with titanium screws and the body of the tray was filled with caucellous bone obtained from the iliac crest. With the tray positioned, three-layer closure was employed and at the end of the procedure, In the post-operative phase, massive oedema the oral mucous membrane was intact. of the tongue, lips and submandibular tissues developed which proved to be very slow
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FIG. 2 Radiological appearances of the tibiae and hands of the case presented. Note the uniform increase of bone density although medullary cavities are still visible. Deformity due to fractures is also obvious. In the hands~~l~~;tof the terminal tufts of the phalanges is
FIG. 3 Skull radiographs of the case presented. Note the increased bone density and the absence of frontal and maxillary sinuses. The nasal cavities are underdeveloped giving a narrow face with close set orbits.
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FIG.
4
A, The patient after the first reconstructive
attempt showing massive oedema of the tongue.‘@ i
B, A plaster model of the patient’s upper ridge alongside an average size edentulous upper model indicating the gross underdevelopment of the maxilla. j
in subsiding (Fig. 4, A). Apart from the oedema, the initial progress was satisfactory but, by the 12th post-operative day, the originally intact oral mucosa had broken down from anterior to the standing lower right first molar to the midline. Bone chips were exfoliating into the mouth. At this stage, it was apparent that the body of the titanium tray was too wide to be accommodated by the tissues and that the head of one of the screws on the right side was prominent. Two weeks following the insertion of the tray, it was decided that the remaining two lower teeth-namely lower right first and second molars-should be extracted, the offending screw replaced in a more suitable position and the tray refilled with bone. This was performed through an intra-oral approach and, prior to being refilled with diced rib graft, the body of the tray was narrowed by bending of the flanges. The intra-oral wound was closed in two layers. This procedure resulted in a further increase of the oedema and, by the fifth postoperative day, a frank left submandibular abscess had developed, which required extraoral drainage. The pus contained necrotic bone chips. Following drainage of the day, oral abscess, the patient’s condition improved, but by the 12th post-operative breakdown had occurred once more in the right buccal sulcus. Initially, this was limited and it was felt that spontaneous healing may occur, but at 7 and IO weeks post-operatively, small intra-oral procedures were carried out in an attempt to re-establish mucosal cover. On both occasions, local modifications were made to the tray by bending in an attempt to reduce its bulk. Even after this period of time, the oedema was still gross, but showing signs of resolution. The second attempt at closure appeared to have given good results but, once more, intra-oral breakdown occurred within 4 weeks. By now, it had become apparent that this approach to reconstruction was a failure and a decision was made to remove the titanium tray and insert a Bowerman-Conroy titanium bar prosthesis. It was only at this time-4 months following the first major reconstructive attempt-that the oedema had settled sufficiently to allow this second approach to be made. Through bilateral submandibular incisions, the titanium tray was removed and the Bowerman-Conroy bar was tunnelled through the intervening tissue in the midline. The bar was secured by two titanium screws to each bone fragment.
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FIG.
The patient’s final appearance at
the
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259
5
completion of surgery, after resolution of the oedema.
Great difficulty was encountered in creating a plane for insertion of the bar with neutral soft tissue tension due to the extreme degree of fibrosis present, and the total absence of normal soft tissue planes. Careful closure in layers was carried out. Initial post-operative progress was encouraging but, as on the previous occasion, surgery produced considerable oedema which fortunately was less severe and showed signs of settling more rapidly. Mucosal breakdown within the mouth was first noticed on the 10th post-operative day, when one of the carefully repaired areas of intra-oral dehiscence broke down once more. This occurred in the right premolar region and after only a few days, it was obvious that purulent saliva was forming in a sump around Fashioning of the titanium bar the prosthesis and further breakdown was occurring. had been a considerable problem in the first instance due to the lack of any normal jaw to act as a guide to contour. As the oedema subsided, it became apparent that the bar inserted was too tight around the base of the tongue and this was felt to be a contributory factor to dehiscence. Eighteen days after the insertion of the first Bowerman-Conroy bar, it was removed This procedure was carried out through and a bar of more generous proportions inserted. bilateral submandibular incisions, the longer bar being placed at a much deeper level in the mass of fibrous tissue that had replaced the submandibular and sublingual tissues. Intra-oral areas of breakdown were repaired. Oedema once again was a post-operative problem, but showed signs of earlier resolution. Following this operation, initial encouraging post-operative progress was maintained for the first time, and breakdown Six weeks after insertion, radiographs did not occur either intra-orally or extra-orally. indicated that the two retaining screws on the left side had pulled loose and they were accordingly replaced by bolts through an extra-oral incision. Nine weeks after insertion of the second titanium bar, the mucosa was still intact
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and it was felt that the tracheostomy should be allowed to close-8 months after its creation. As the oedema continued to subside, it was apparent that the facial musculature was still capable of functioning and, although the facial nerve branches had never been identified amongst the dense scar tissue, innervation was intact and lip seal returned. Fluid intake was maintained intravenously in the post-operative periods, but oral fluids and fluid diet were encouraged as early as possible. Nasogastric feeding was resorted to whilst the oedema was gross, but once recovery was underway, tolerance of the nasogastric tubes was poor and they were frequently removed by the patient. All major surgery was covered by antibiotics-ampicillin and flucloxacillin being used. Only on one occasion was acute infection a problem and this resolved following drainage of a submandibular abscess. Infection was otherwise not a problem; the frequent, although inconsistent, positive cultures being probably the result of tissue breakdown associated with the exposure of a foreign body rather than the primary cause. As, the patient continued to improve, it became possible to construct a full upper denture which was well retained, despite the diminutive ridge (Fig. 4, B). He was advised against the construction of a lower denture at any time, in view of the ever present possibility of pressure necrosis of the poor quality tissues overlying the mandibular prosthesis. The patient’s final appearance is shown in Figure 5. DISCUSSION The diagnosis of pycnodysostosis was made radiologically and, as in Elmore’s cases, the most striking features are seen in the radiographs; the generalised increased radiodensity of the skeleton being a prime diagnostic feature. The patient had brachycephaly but, unlike many of the reported cases, the cranial sutures and fontanelles were closed. The maxillae were extremely hypoplastic, as can be seen in the radiographs and from the upper dental model. Antra were small and the frontal sinuses virtually absent. Mandibular development was impossible to assess in view of the gross nature of the disease process. Increased radiodensity of the vertebral end plates was apparent, but vertebral fusion was not noted. Medullary cavities in the limbs were ill-defined and multiple healed fractures of the tibiae were visible. Phalanges were tapered with lysis of the terminal tufts. Hypoplasia of the clavicles was noted along with evidence of healed rib fractures. The physical findings bore a striking resemblance to those described by Ehnore, particularly with regard to the physique and facial appearance. The normality of laboratory investigations is another feature worth noting. Bone biopsies taken at the time of operation showed dense bone of otherwise normal architecture (Fig. 6). Chromosome studies were not undertaken. There was no evidence of mental retardation. Fractures of the mandible during tooth extraction have been reported in three cases of pycnodysostosis by Blasi (Ig37), Krabbe (1950) and Lievre et al. (Ig64), but no comment is made regarding their progress. In a fourth case reported by Emami-Ahari et al. (1969) the fracture is recorded as having been treated by sequestrectomy and curettage but the outcome is not stated. The abnormal density of the bone, would seem, however, to make osteomyelitis a very real danger in such circumstances. Fractures of the mandible and osteomyelitis are reported to be common sequelae of tooth extraction in patients suffering from osteopetrosis, because of the increased bone density and the reduction of the medullary spaces
PYCNQDYSOSTOSI:
S-A
RARE
DISORDERCOMPLICATING
EXTRAC :TION
FIG. 6 Hiistological appearance of bone specimens taken during surgery. A, x40. B, x (H. & E.) Note the dense Haversian systems of otherwise normal architecture.
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(Shafer et al.,
BRITISH 1974).
Inpycnodysostosis,
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with cleidocranial dysostosis, there is no such association. uncomplicated fractures are reported to heal normally (Elmore,
1967). Important features that differentiate pycnodysostosis from osteopetrosis are the presence of a demonstrable medullary cavity in the long bones in pycnodysostosis and the presence of active medullary haemopoiesis. There is no anaemia or hepatosplenomegaly that would suggest extra-medullary haemopoiesis. Anaemia may be progressive in osteopetrosis, thus reducing life expectancy, but this is not a feature of pycnodysostosis. The stature of sufferers from osteopetrosis is generally normal and tapering phalanges and ungual tuft lysis are not consistent findings. Cleidocranial dysostosis and pycnodysostosis are both associated with patent fontanelles, separated sutures, deficient clavicles and abnormalities of dental eruption and resorption. Dense, fragile bones, however, are not a feature of cleidocranial dysostosis, neither are tapering phalanges and the absence of ungual tufts. Cleidocranial dysostosis is inherited as an autosomal dominant characteristic, whereas the inheritance of pycnodysostosis appears to be an autosomal recessive trait. Englemann’s disease or progressive diaphyseal dysplasia is a condition associated with increased bone density, but patients with this disorder are tall with abnormally long limbs. They are normal in infancy and the characteristic changes do not The skull is not involved and shows become apparent until well into childhood. none of the characteristic changes of pycnodysostosis. Idiopathic non-familial acre-osteolysis is a rare condition combining lysis of the terminal phalanges, separation of the cranial sutures and frequent fractures. However, skeletal radiodensity is not a feature of this condition. Skeletal fluorosis is another cause of generalised skeletal radiodensity, but bone fragility is not a feature of this condition (Hunter, 1964). Calcification of ligaments and tendons occurs in fluorosis and this is radiologically demonstrable. This is a feature not present in pycnodysostosis. Osteopoikilosis (Duthie & Ferguson, 1973) is a rare condition producing patchy skeletal sclerosis, whereas, in pycnodysostosis, the sclerosis is diffuse. This case presented some unusual problems that warrant further consideration. The dense nature of the bone obviously makes dental extraction a hazard from the point of view of jaw fracture and subsequent infection, as already The reconstructive difficulties were compounded by the gross nature mentioned. of the jaw defect and the dense fibrosis that had resulted from chronic infection and previous surgery, thus preventing an accurate estimate of the original jaw The resultant lack of tissue planes made dissection difficult and gave contour. no assistance in determining a suitable plane or contour for the prostheses inserted. The original titanium tray prosthesis is a case in point and in retrospect it was apparent that the tray was too wide to be accommodated within the tissues. The oral mucosa became tented or stretched across the width of the tray, and this factor, together with some degree of unavoidable dead space, made breakdown almost inevitable even with the metal edges protected with silastic. Attempts to narrow the tray by bending the flanges in situ were fruitless because, although the width was reduced, the dead space was increased. Bone used in the reconstructive attempts was probably abnormal, as it was autogenous. This may well have predisposed to failure of the grafts and the
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of post-operative infection in one instance. Another possible cause of frequent wound breakdown was thought to be the abnormal bone turnover, and it is postulated by the authors that normal osteoclastic action is probably necessary to ‘etch’ the bone surface to allow the attachment of fibrous tissue associated with healing and repair. Post-operative oedema was a notable problem during the reconstructive Following insertion of the titanium tray prosthesis, gross oedema of surgery. the lips and tongue persisted for 8 weeks. It is considered that this was due to obstruction of the lymphatic and venous drainage arising from a combination of bilateral extra- and intra-oral incisions, gross fibrosis from previous surgery, and mechanical constriction of the base of the tongue by the titanium tray. This was a problem that persisted during his stay of 9 months, but there was a gradual improvement as time passed. The gross oedema underlined once more the value of the initial tracheostomy.
onset
ACKNOWLEDGEMENTS 8ur thanks are extended
to Dr F. Starer, Consultant Radiologist, at the Westminster Hospital, who originally made the radiological diagnosis and to Professor A. D. Morgan, who performed the histological examinations. We are also indebted to the stafl of the Photographic Department of the Westminster Hospital, for their excellent illustrations, and to Miss Jill We wish to acknowledge our appreciation Mountain for her services in the typing of this paper. of the assistance of Mr John Williams, Senior Registrar, at the commencement of this patient’s treatment. Especial thanks are extended to Dr Stanley Elmore for permitting the use of one of his illustrations in this paper.
REFERENCES APLEY, A. G. (1969). Recent Advances in Orthopaedics. London: Churchill. BLASI, R. (1937). Radiologica Medica, 24, 741. COLLADO-QTERO, F. (1956). Acta Pediatrica Espanola, 14, I. DUTHIE, B. D. & FERGUSON, A. B. (1973). Mercers Orthopaedic Surgery. London: Arnold. ELMORE,S. M. (1967). Journal of Bone and Joint Surgery, 49-A, 153. EMAMI-AHARI, Z., ZARABI, M. & JAVID, B. (1969). Journal of Bone and Joint Surgery, 51B,
307. GIACCAI,L., SALAAM,M. & ZELLWEGER, H. (1954). Acta Radiologica, 41, 417. The Diseases of Occupations, London: English Universities Press. HUNTER, D. (1964). KRABBE,K. H. (1950). Folia Psychiatrica, Neurologica, Neurochirurgica Neerlandica, 53, 328. Revue Rhumatisme, 31, 282. LIEVRE, J-A., CHADUT, A. & CAMUS, J. P. (1964). _MAROTEAUX, P. & LAMY, M. (1962). Archives FranGaises de Pediatrie, 19, 267. J ournal of the American MAROTEAUX, F. & LAMY, M. (1965). Medical Association,
191,
715. Chirurgia Organi Movimento, 7, 379. MONTANARI, U. (1923). SEDANO, H. D., GORLIN, R. J. & ANDERSON, V. E. (19%). American Journal of Diseases of Children, 116, 70. SHAFER, W. G., HINE, M. K. & LEVY, B. M. (1974). A Textbook of Oral Pathology.
Philadelphia and London: Saunders.
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